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Fishery Assessment Report

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									      Fishery Assessment Report


 The South East Fishery

               1999

             DRAFT




             Compiled by

the South East Fishery Assessment Group




              Edited by

        Anthony D. M. Smith
       CSIRO Marine Research
    Commonwealth of Australia 1999


ISSN 1326 - 9802


This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be
reproduced by any process without prior written permission from the Australian Fisheries Management
Authority. Requests and inquiries concerning reproduction and rights should be addressed to: AFMA, PO
Box 7051, Canberra Mail Centre, ACT 2610.




Copies available from:
Australian Fisheries Management Authority
John Curtin House
22 Brisbane Avenue
Barton ACT 2610
Ph: (02) 6272 5029


Preferred way to cite this publication:
Smith, A.D.M. (ed) (1999) The South East Fishery 1999, Fishery Assessment Report compiled by the
South East Fishery Assessment Group. Australian Fisheries Management Authority, Canberra.




This series of Fishery Assessment Reports documents general fishery assessment issues dealt with by the
Fishery Assessment Working Groups established by Commonwealth Fishery Management Advisory
Committees. It addresses the issues of the day in the current legislative context and in the timeframes
required. The documents are not intended as definitive statements on the subjects addressed but rather as
progress reports on ongoing investigations.




ii                                                             SEF Fishery Assessment Report 1999
CONTENTS
EXECUTIVE SUMMARY.............................................................................................. IV
ACKNOWLEDGMENTS ......................................................................................... XXVII
INTRODUCTION ............................................................................................................ 1
SOUTH EAST FISHERY ASSESSMENT ..................................................................... 2
1.      THE FISHERY ....................................................................................................... 2
2.      MAJOR STAKEHOLDERS ................................................................................ 20
3.      AUSTRALIAN FISHERIES MANAGEMENT AUTHORITY (AFMA)
        MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE
        INDICATORS ...................................................................................................... 21
4.      SOURCES AND STATUS OF DATA ................................................................ 23
5.      PREVIOUS STOCK ASSESSMENTS ............................................................... 25
6.      1999 STOCK ASSESSMENT PROCESS .......................................................... 27
7.       ECONOMIC STATUS ........................................................................................ 28
8.      ENVIRONMENTAL FACTORS ........................................................................ 37
9.      MANAGEMENT IMPLICATIONS ................................................................... 39
10.      RESEARCH NEEDS ........................................................................................... 42
11.     CONSISTENCY WITH FISHERIES ECOSYSTEM MANAGEMENT ....... 44
12.      FISHERY ASSESSMENT GROUP WORK PLAN, 1998-99 .......................... 46
13       SPECIES SUMMARIES
         BLUE EYE TREVALLA..................................................................................... xx
         BLUE GRENADIER............................................................................................ xx
         BLUE WAREHOU .............................................................................................. xx
         FLATHEAD .......................................................................................................... xx
         GEMFISH EASTERN ......................................................................................... xx
         GEMFISH WESTERN ........................................................................................ xx
         JACKASS MORWONG ...................................................................................... xx
         JOHN DORY ........................................................................................................ xx
         LING ...................................................................................................................... xx
         MIRROR DORY .................................................................................................. xx
         OCEAN PERCH................................................................................................... xx
         ORANGE ROUGHY ........................................................................................... xx
         REDFISH .............................................................................................................. xx
         ROYAL RED PRAWN ........................................................................................ xx
         SCHOOL WHITING ........................................................................................... xx
         SILVER TREVALLY .......................................................................................... xx
         SPOTTED WAREHOU ....................................................................................... xx




SEF Fishery Assessment Report 1999                                                                                                  iii
EXECUTIVE SUMMARY
GENERIC ISSUES
    Industry information on fishing practices and their effects on catch rate analysis: The results of a
     FRDC funded survey of the SEF conducted by Drs Baelde and Prince were discussed. It was stressed
     that fishing practices are now very much driven by fishers‘ quota holdings. Catch value is now
     considered more important than catch volume and there has been a pronounced shift to ―mixed-bag‖
     fishing by the ―inshore‖ fleet since quota introduction. Market demand/price is as important a factor as
     fish availability. The need to maximise the value of quota holdings by using them throughout the year
     is probably driving catch rates down. Since economic factors are one of the main forces behind fishing
     practices they should be included in any analysis of catch rates. During discussions of the various
     factors influencing catch rates, the Group agreed that aggregating trawl data across the fishery was of
     little use and more sophisticated spatial/temporal analysis was needed. Also, catch data from ―high-lift‖
     and ―scratch‖ nets should be separated. Whereas the Group agreed that technological advances have
     resulted in a unidirectional increase in fishing power/efficiency, the magnitude of such increase was
     unclear.
    The Group agreed that ongoing, improved consultation with industry is vital to gaining a better
     understanding of the SEF.
    The above survey and port surveys revealed a widespread industry perception that ―if a TAC is
     significantly under-caught, it will inevitably be reduced in the future‖. The Group wishes to place on
     record that the level of catch against a TAC in a given year has little influence on the SEFAG stock
     assessment process.
    The Group flagged the need to evaluate the cost of continuing attempts to standardise catch rates
     against the cost of initiating and maintaining fishery-independent abundance indices.
    Fishing effort: The Group expressed concern at the continuing rise in trawl fishing effort. The 1997
     SEF1 total of 101 243 hours bottom-time is the highest annual total since SEF1 records began in 1985
     and is 7.6 per cent higher than 1996, continuing a trend that began in 1993.
    The Group noted that three ABARE studies of the SEF are currently under way and flagged the need
     for better communication between SEFAG and ABARE. It is anticipated that the outputs from these
     studies can be incorporated into the 1999 FAR.
    The Group strongly supported the recently commenced study by Dr Punt (CSIRO), ―Defining Robust
     Harvest Strategies and Performance Indicators and Monitoring for the SEF‖, and discussed the most
     suitable SEF species for inclusion.
    The Group flagged the need to allow more time to discuss generic and strategic issues at future SEFAG
     meetings.
    The Group confirmed that assessment workshops would be held for blue-eye trevalla and ling during
     1998/99. One aspect of these workshops would be to assess if information availability justified the
     creation of Assessment Groups for these species.
AFMA PERFORMANCE CRITERIA
The Group discussed the usefulness of the ―CPUE strategy‖:
 ―where estimates of biomass are not yet available, but may be at some point in the future, to ensure that
catch per unit effort (CPUE) is maintained above its lowest annual average level from 1986 to 1994.‖
This is the default strategy for a large number of the SEF quota species, and in 1997 five quota species
―triggered‖ this performance criterion. A number of problems with this strategy were discussed and the
continued use of this approach needs to be rigorously evaluated.
A strategy is a set of performance indicators and associated actions. The ―CPUE strategy‖ is not a strategy,
but a restatement of the performance criterion. There is no specification of how the criterion would be
achieved (how TACs should be set), nor of what response would be made if the criterion is triggered.




iv                                                              SEF Fishery Assessment Report 1999
The (implied) objective itself does not seem to make sense. For example, it would imply that it would be
acceptable to maintain a depleted stock in a depleted state. It would also imply that a lightly exploited
resource could not be developed as this could result in a decline in CPUE.
There was considerable discussion and concern about the use of catch rates as a measure of stock status,
given the influence on CPUE of: environmental factors; fishing practices; market factors; technological
trends; and management regimes. One result of this is that even when the performance criterion is triggered,
no action may be taken because of the uncertainty in interpretation of the result.
The meeting agreed that redevelopment of strategies for these species would be based on: development of
appropriate strategies and performance criteria through the Assessment Groups and SEFAG; outcomes of
the new FRDC project on evaluation of robust harvest strategies; and even broader evaluation of
management strategies for the SEF generally.

SPECIES SUMMARIES AND MANAGEMENT IMPLICATIONS
Quantitative assessments were conducted for blue grenadier, blue warehou and redfish by their Assessment
Groups. Whereas a quantitative assessment was also conducted for orange roughy, this was not agreed to by
ORAG industry members. A quantitative assessment will also be conducted for eastern gemfish by EGAG
after the 1998 survey of the winter spawning run is completed. No quantitative assessments were conducted
for the other quota species.
There were five species/species groups which triggered AFMA‘s catch rate performance criterion in 1997;
namely, John dory, mirror dory, ocean perch, school whiting and spotted warehou. SEFAG resources were
mainly directed towards updating the stock assessment reports for these five species and those for blue eye
trevalla and ling. Comparatively little attention was paid to the remaining five quota species; flathead,
jackass morwong, royal red prawn, silver trevally and western gemfish. The main data sources used were
the SEF2 and SEF1 databases, the SMP/ISMP and, where appropriate, the results from a recent fishery
independent trawl survey by the FRV Kapala between Sydney and Gabo Island.
In the following species summaries, the Commonwealth trawl catch totals are derived from the SEF2
landings database and the Commonwealth non-trawl totals are derived from the GNO1 database and are
split into Commonwealth and State catches for dual-endorsed SEF vessels. Distinction is made between
agreed TACs (as determined by the AFMA Board) and actual TACs (the agreed TAC plus or minus: carry-
over/under).




SEF Fishery Assessment Report 1999                                                                            v
Blue eye trevalla Hyperoglyphe antarctica
Assessment or working group:        None

Recent workshops: 19-20 April, 1999, Hobart

Previous quantitative assessment: None

1998 fishery:

Since 1998, blue eye trevalla trawl and non-trawl catches have been managed under a global agreed TAC of
630 t (530 t non-trawl, 100 t trawl sector), with an actual TAC of 646 t. The 1998 SEF2 trawl total was 96
t (all Commonwealth waters), being 82% of the actual TAC of 116 t and 96% of the agreed TAC of 100 t.
Total non-trawl landings were 381 t (Commonwealth waters only), being 70% of the actual TAC of 542 t
and 72% of the agreed TAC of 530 t. Non-trawl operators report that the drop in the non-trawl catch in
1998 was due to the introduction of quota and unfavourable environmental conditions. Non-
Commonwealth catches off NSW were estimated at around 105t for the 1997/98 financial year. Trawl
operators in some areas report an increased by-catch of blue eye, and problems in leasing quota to cover it.

1999 assessment: There is no quantitative assessment for this species.

The April 1999 workshop reviewed the biology of the species and trends in catches, catch rates and size
and age composition. Assessment of the fishery is complicated by complex spatial and seasonal variability
in size-structure and availability of the fish, multiple gear types, gear selectivity, and jurisdictional factors.
An increase in non-trawl catch rates from the mid-1980s most likely reflects changes in fishing patterns and
fishing gear. Catches from both sectors mainly comprise young, immature fish, while larger, mature fish are
caught on deeper grounds or from seasonal spawning aggregations. The size-dependent vulnerability to
various fishing gear types would need to be taken into account when assessing any impact of transferability
of quota between fishing sectors in the fishery. The spatial stock structure remains unknown, particularly
with regard to the relationship between the fish on the continental slope and on offshore sea-mounts.

Management implications:

Stock indicators such as trends in catch rates and size composition do not suggest major concerns with
current catch levels in the short term. Obtaining quota to cover trawl by-catch is of concern in some areas.
There could be implications for the proposed extension of the trawl fishery into the EDWT area, depending
on possible trawl exclusion areas.

Research priorities:

The 1999 workshop recommended the formation of a Blue Eye Working Group to compile existing data
before undertaking a quantitative assessment. SEFAG stressed the need for improved monitoring of non-
trawl catches.




vi                                                                SEF Fishery Assessment Report 1999
Blue warehou Seriolella Brama

Assessment or working group:        BWAG

Recent workshops: 3 meetings of BWAG in the past year.

Previous quantitative assessment: 1998 BWAG assessment

1998 fishery:

The 1998 landed weight of blue warehou caught by trawl was (SEF2) 932 t (921t Commonwealth waters
and 11 t State waters). The 1998 trawl catch in Commonwealth water represents about 86% of the actual
(and leased from non-trawl) TAC of 1,074t and 112% of the agreed TAC of 820t. It represents an increase
in landings compared to 1997 (794t). The trawl component of the 1999 agreed global TAC was 718t, with
the actual trawl TAC being 837t.

The 1998 landings from the non-trawl sector were 78t, representing only about 8% of the actual TAC of
984t and 7% of the agreed TAC of 1,180t. The 1998 landings were considerably lower than in 1997 (273t).
The agreed global TAC for 1999 was set at 1,750t (718t trawl and 1,032t non-trawl). Landings recorded
for Tasmanian endorsed vessels showed an increase from 127 t in 1997 to an estimated 213t in 1998. The
estimated recreational catch in Tasmania is between 100 and 150t.

1999 assessment:

There were continued improvements in the assessment of blue warehou during 1999. The assessment was
based on an ‗integrated analysis‘ approach which included information on catches, discard rates, catch
rates, and the length/age of discards and landed catch. This approach is more flexible that the fleet-
disaggregated Virtual Population Analysis used in the 1998 assessment. The current assessment uses length
and age data separately, accounts for errors in ageing, and datasets with low sample sizes need not be
included, unlike the VPA. The analysis is based on four fleets (―western trawl‖, ―eastern trawl‖, ―non-
trawl‖ and the Tasmanian meshnet fishery).

For the eastern trawl fleet, standardised CPUE initially increases to a peak in 1990 dropping to a lower
level by 1992 and remaining relatively stable from 1994. The trend in CPUE for the western fishery is one
of continuous decline from 1991 to 1996 with an upturn in 1997 and 1998. The age-composition data
suggest that this is due to a strong year class entering the fishery and growing into its second and third year.
The trawl sector argues that the decline in catch rates can, in part, be attributed to changes in trawl sector
fishing practices and is not solely due to changed abundance. Standardised CPUE for the non-trawl fleet
was variable up to 1990 but has subsequently declined. There was a slight upturn in 1997, followed by a
decline in 1998. Because the non-trawl effort data do not include searching time, the results represent the
minimum decline. The non-trawl sector was very pessimistic about the status of the resource. Catch and
effort data were not available for the Tasmanian fishery. Current catches in this fishery, which are not
included in the TAC, contribute a significant component of total landings and impact projections. In
addition, the recreational catches (not included in the assessment) may be in excess of 150t per year.

Size- and age-composition data are consistent with variable recruitment with a relatively ―strong‖ year class
particularly evident off the east coast during 1997.

The current assessment uses data up to, and including, 1998. The results suggest that the spawner biomass
peaked between 1987 and 1989, dropped markedly to 1994 and has remained relatively stable since. The
spawner biomass in 1998 was about 30% of peak levels. The 1996 cohort (fish aged 2 in 1998) is the
strongest detected to date (but the least certain). The other key uncertainty is whether the (standardized)
catch rates reflect changes in abundance.

A risk analysis based on 5 and 10-year projections was undertaken (see main report). Three performance
indicators were used in the projections:
   P(B > B97) – the probability that the projected biomass is greater than the biomass in 1997


SEF Fishery Assessment Report 1999                                                                           vii
      P(B > min [B91 > B97]) – the probability that the projected biomass is greater than the minimum
       biomass between 1991-97
      P(F < M) – the probability that the projected fishing mortality is less than natural mortality

The results were insensitive to the 1999 catch and the split of this catch between fleets but were very
sensitive to the projection period and the performance indicator chosen. For example, a Commonwealth
TAC of 2000t leads to greater than 50% probability of the biomass being above the minimum biomass
between 1991-1997 for a 5-year projection but a less than 30% probability for a 10-year projection. For the
fishing mortality indicator, the 5-year projection for a 2000t TAC gives a less than 20% probability of
fishing mortality being less than natural mortality for a 2000t TAC, but a less than 10% probability for the
10-year projection. The differences between projections reflect the influence of the 1996 cohort as it passes
through the fishery. The results were consistent for a range of sensitivity analyses.

Management implications:

The (Commonwealth) TAC required to achieve a 50% probability or better of satisfying each performance
indicator over 5 years is: 2000t (P(B > B 97)); 2000t (P(B > min [B91 > B97])); and 1300t (P(F < M)). The
TAC predicted to meet all of the criteria is 1300t.

Research priorities:

The assessment suggests that the blue warehou population is influenced strongly by variation in
recruitment. One implication of this is that higher yields can be achieved by conducting annual assessments
and modifying TACs in response to changes in year-class strengths. However, future assessments will need
to consider the implications of shifts in effort between sectors.

SEFAG recommends that BWAG continue for at least one more year. Next year‘s assessment should
examine a range of refinements including further analyses of non-trawl catch rates.




viii                                                               SEF Fishery Assessment Report 1999
Blue grenadier Macruronus novaezelandiae

Assessment or working group:       BGAG

Recent workshops: Three meetings of BGAG in the past year.

Previous quantitative assessment: 1998 BGAG assessment

1998 fishery:

The 1998 SEF2 landed weight of blue grenadier was 5,734 t, which was about 46% of the allocated TAC of
12409t. It represents an increase in landings compared to 1997 (4534t). The 1999 TAC is 10000t, with the
allocated TAC being 11,921t.

There are two distinct components to the blue grenadier fishery within the SEF. The non-spawning fishery
concentrates principally on 4-5 age classes of juveniles and sub-adults. There is considerable variation in
recruitment and because of the relatively few age classes in this fishery, there is considerable variability in
annual catch rates. The winter spawning fishery targets mature fish and, typically, catches contain over 10
age classes. Catches in this fishery contain a far greater proportion of large and old blue grenadier than is
seen in the non-spawning fishery. Industry reports that it anticipates the 10,000t TAC will be taken during
1999 due to the continuing development of the spawning fishery.

1999 assessment:

The 1999 assessment of blue grenadier uses the age-structured ‗synthesis‘ model developed during 1998
with the inclusion of 1998 data. The assessment considers fishing during the spawning season off Western
Tasmania and that at other times/places separately. The model uses catch (including discards), standardised
catch rates and catch-at-age data as well as estimates of absolute abundance based on the egg production
method. A risk analysis evaluates the consequences of different future levels of harvest by the
spawning/non-spawning fisheries

The catch rate data were standardized to remove some of the impact of changes in fishing practices/fleet
composition. Standardised catch rates in the non-spawning fishery declined from 1991 due to a series of
weak year-classes entering the fishery. Two strong year classes are currently entering the fishery and catch
rates consequently rose in 1998. Discarding in the non-spawning fishery was extremely high during 1997
and 1998, estimated at over 2,500t and 1,300t, respectively. This discarding is a cause of concern because
of the waste of future yield, the potential impact on future egg production (particularly for poor year
classes) and increased uncertainty of stock assessments. The Group highlighted the importance of the
discard data provided by ISMP to the blue grenadier assessment, particularly as it relates to recruitment.
Standardised catch rates in the spawning fishery were variable but were relatively low, although stable,
during 1995-98. As the strong year classes are anticipated to enter the spawning fishery during 1999 and
2000, it is expected that catch rates will rise.

The spawner biomass is estimated to have declined continuously from 1979 to 1998 although the levels of
fishing mortality have generally been less than 10%. One of the main reasons for the reductions in recent
years was that 1989 to 1993 year classes were well below average. The spawner biomass is predicted to
recover once the strong 1994 and 1995 year-classes reach age 5 and enter the spawner biomass. The 1999
assessment is more optimistic than that conducted in 1998 because the strength of the 1993 year class was
not as weak as previously estimated, following the inclusion of 1998 data. Key uncertainties include
whether the egg surveys provide absolute measures of abundance, and the (absolute) strength of recent year
classes.

Management implications:

The 1999 base case assessment indicates that a TAC of 10,000t, for 20 years, has a low risk of reducing the
spawning biomass to below 40% of virgin biomass. However, the assessment is extremely sensitive to
whether the egg survey estimate is regarded as a measure of absolute or relative abundance. For example,


SEF Fishery Assessment Report 1999                                                                          ix
if the true abundance is half the egg estimate then the risks will be substantially higher than for the base
case. If the egg estimates underestimate the true biomass by 50%, catches of 15,000t will be sustainable
whereas with the half egg estimate a 15000t TAC for 20 years leads to a high probability of the biomass
dropping below 40% of virgin biomass.

Research priorities:

BGAG will move to more formally evaluate harvest strategies in the next year, and in particular how to
manage in the face of large year to year variations in recruitment. The maturity ogive for the species needs
to be determined as does the percent non-spawning.




x                                                              SEF Fishery Assessment Report 1999
Flathead Platycephalus sp., Neoplatycephalus sp.

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: Estimates of sustainable yields from late 1980s

1998 fishery:

The 1998 SEF2 total was 2664t (2543t Commonwealth, 121 t State). The catch from Commonwealth
waters represented 63% of the actual TAC of 4009t and 73% of the agreed TAC of 3500t. The 1999 agreed
TAC is 3500t, with an actual TAC of 3966t.

1999 assessment:

There was no formal quantitative assessment of flathead in 1999.

Catch rates (unstandardized) for both trawl and Danish seine declined from 1989 to 1994, particularly in
Eastern Sector B. There was also a decrease in the proportion of larger, older tiger flathead (7 years or
more) in eastern Bass Strait and southern NSW catches. Length and age structure of catches has been
reasonably stable in recent years.

Previous estimates of fishing mortality obtained from the age composition of catches were relatively high.
These results indicated that tiger flathead abundance in the eastern Bass Strait area had been declining, both
in number and biomass, from the late 1980s. However, catch rates of both fleets have improved since 1995.
Industry expressed no concerns about the resource in recent port meetings and stressed that landings are
largely driven by market demand.

Discarding rates of tiger flathead remain a concern. This problem is highest in NSW where a 13 inch
minimum size limit is enforced and the discrepancy between size limits in NSW and Victoria (11 inch)
needs to be addressed.

Management implications:

Estimates of fishing mortality are high. The current allocated TAC is above previous estimates of long-term
sustainable yield (2500t), and above levels that have previously led to overfishing..

Research priorities:

SEFAG recommended that a high priority be given to an updated assessment for tiger flathead, and
recommended this be done via a workshop (rather than a new assessment group). A study to assess the
effects of either raising the Victorian size limit or lowering the NSW limit is required.




SEF Fishery Assessment Report 1999                                                                          xi
Eastern gemfish Rexea solandri

Assessment or working group:     EGAG

Recent workshops: 3 meetings of EGAG in the past year

Previous quantitative assessment: 1998 EGAG assessment

1998 fishery:

The 1998 agreed TAC was zero (no targeted fishery). A 300t TAC was allocated to trawl quota holders to
manage by-catch. A further 100t was allocated for research. Trip limits in NSW were as follows in 1998:
zero south of Barrenjoey inside 3nm; 150kg south of Barrenjoey outside 3nm; 200kg north of Barrenjoey.

The 1998 trawl catch was 222t (summer + winter) with a further estimated discard of 47t. The
Commonwealth non-trawl catch was 5t. The NSW state catch was 109t (dropline) and 3t north of
Barrenjoey. The total estimated catch for 1998 (including discards) was 386t.

A zero targeted trawl TAC was set for 1999, with 250t provision for by-catch. NSW trip limits north of
Barrenjoey were reduced in 1999 to 150kg.

1999 assessment:

The results of the 1999 assessment will be made available after the EGAG meeting on 16-17 August. This
meeting will examine assessment results incorporating data from the 1999 summer and winter spawning
fisheries.

Management implications:

To be advised.

Research priorities:

Work should continue on the design of a future monitoring program, including relative abundance surveys
and catch composition.




xii                                                         SEF Fishery Assessment Report 1999
Western gemfish Rexea solandri

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 185t (all Commonwealth waters), 55% of the actual TAC of 334t and 62% of the
agreed TAC of 300t. The 1999 agreed TAC is 300t, with an actual TAC of 346t.

1999 assessment:

There was no formal quantitative assessment of western gemfish in 1999.

Unlike eastern gemfish, most of the western gemfish catch is taken in multi-species catches,
usually with blue grenadier and ling. Although the AFMA catch rate performance criterion
was triggered in 1995, this has not occurred in recent years. Landings of western gemfish by
the GAB trawl fishery in 1998 were 85t and if this fishery continues to develop, priority
should be given to developing complementary management measures. As western gemfish in
the SEF appear to be at the eastern end of their distribution, it is unclear if changes in catch
rates are in any way related to overall stock abundance. Stock status remains unknown.

Management implications:

Consideration should be given to complementary management arrangements in the GAB fishery.

Research priorities:




SEF Fishery Assessment Report 1999                                                                 xiii
Jackass morwong Nemadactylus macropterus
Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: 1997 stock assessment report (based on late 1980s assessment by KR
Allen)

1998 fishery:

The 1998 SEF2 total was 883t (878t Commonwealth, 5t State). The catch from Commonwealth waters
represented 49% of the actual TAC of 1779t and 58% of the agreed TAC of 1500t. The 1999 agreed TAC
is 1500t, with an actual TAC of 1811t.

1999 assessment:

There was no formal quantitative assessment of jackass morwong in 1999.

Catches have been stable and (unstandardized) catch rates have been declining. There is evidence from
length frequency data of a strong year class coming into the eastern sector. Recruitment for this species has
been historically variable.

Stock structure has still not been resolved, but an otolith microchemistry study suggesting two SEF stocks
now seems much more unlikely. The jackass morwong TAC has remained at 1500t since 1992, but has
never been reached. However, this TAC was partly based on yield estimates derived from parameters
calculated from whole-otolith ageing. Recent sectioned-otolith ageing data show morwong to have greater
longevity (35 yrs) and lower mortality rates than were previously reported, implying a less productive
resource. Mean unstandardised catch rates triggered AFMA‘s catch rate performance criterion in 1995,
1996 and again in 1998. Current stock status is unknown.

Management implications:

New interpretation of ageing suggests that the current TAC may exceed the sustainable yield. However
catches are presently well below the TAC. This species continues to trigger the catch rate indicator.

Research priorities:

A high priority should be given to re-ageing old otoliths and ageing recent otoliths, so that a new
assessment can be made. This is the third highest priority species for a (new) quantitative assessment (after
spotted warehou and tiger flathead).




xiv                                                            SEF Fishery Assessment Report 1999
John dory Zeus faber

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 127t (115t Commonwealth, 12t State). The catch from Commonwealth waters
represented 39% of the actual TAC of 296t and 48% of the agreed TAC of 240t. The 1999 agreed TAC is
240t, with an actual TAC of 287t.

1999 assessment:

There is no quantitative assessment for this species.

John dory is largely taken as a by-catch of fishing for other shelf species. Thus, the size of the John dory is
largely dependent upon the total amount of fishing effort directed towards the depth strata occupied by John
dory. Because of the bycatch nature of the fishery, it is very unlikely that changing the TAC for this species
will alter fishing mortality. There are small catches (<10t) of John dory from the trawl fishery north of
Barrenjoey, and recreational catches are uncertain but thought to be small. Stock status remains unknown.

Since 1995 mean unstandardised catch rates have triggered AFMA‘s catch rate performance criterion. It
was again triggered during 1998. Part of the overall decline in SEF catch rates may be attributable to the
ongoing increase in effort in Eastern Sector B. However, catch rates in Eastern Sector A (which usually
supplies 80% of the total landed weight) have fallen since 1994, particularly from 1996 to 1997, despite a
decrease in fishing effort. Trawl effort in Eastern Sector A waters of <200m depth has exhibited a steady
decline since 1994 and increased fishing pressure cannot be held primarily responsible for the decline. The
declining catch rate is thus probably associated with declining abundance. This apparent decline in
abundance is possibly environmentally driven. There is evidence to suggest a strong cohort recruited to the
fishery during 1998. It is unclear what effects this may have on future catches and catch rates. There are no
long term trends in size structure.

Management implications:

Because of the bycatch nature of the fishery, it is very unlikely that changing the TAC for this species will
alter fishing mortality.

Research priorities:

SETMAC has given a low research priority to this species because it constitutes a low volume fishery.
However, if catch rates continue to decline consideration should be given to raising the priority for this
species.




SEF Fishery Assessment Report 1999                                                                          xv
Ling Genypterus blacodes

Assessment or working group:       None

Recent workshops: December 1998, Canberra

Previous quantitative assessment: None

1998 fishery:

1998 SEF2 landings were 1692t (1679 t Commonwealth, 13t State). The Commonwealth catch was 86% of
the actual TAC of 1963t (including 51t leased from non-trawl) and 88% of the agreed TAC of 1921t.
Commonwealth non-trawl landings were 202t, 89% of the actual TAC of 228t (excluding the 51t leased)
and 72% of the agreed TAC of 279t. The 1999 agreed ‗global‘ TAC of 2400t (2095t trawl, 305t non-trawl)
was 200t higher than 1998, with an actual TAC of 2583t (2278t trawl, 305t non-trawl). Annual SEF trawl
landings have risen as a result of higher TACs and consequent increased fishing for ling, particularly west
of Bass Strait. Non-trawl catches have largely stabilized after increasing sharply during 1992/93 and are
now limited by the global TAC. The 1998 landed catch from all sectors (including state) was 1913t, the
second highest on record. Ling is now the third most valuable species in the SEF.

1999 assessment:

There was no formal quantitative assessment of ling in 1999.

The workshop held in December 1998 brought together biological and fishery data for this species.

Whereas present catches are much greater than historical levels, unstandardized and standardized trawl
catch rates across the fishery have remained comparatively stable from 1986 to 1998, suggesting that ling
biomass has not decreased. A recent survey by FRV Kapala also indicated that ling abundance did not
decrease between 1976/77 and 1996/97 off southern NSW. However, there have been significant downward
changes in the size/age structure of both trawl and non-trawl catches from Eastern Sectors A and B, where
about 80% of the trawl catch is now (97 and 98) comprised of comparatively small fish aged 2 years or less.
Catches from west of Bass Strait and the hook sector catches contain a greater proportion of older and
larger fish. Stock status remains unknown, but preliminary results from a current study of ling stock
structure suggest that SEF fish may not be a single stock. Also, industry has reported separate spawning
localities.

Although ling catch rates appear to be relatively stable, the downward shift in the size/age of Eastern Sector
fish indicates that the fishery is having a significant impact. Also, preliminary mortality estimates derived
from Eastern Sector catch curves were high (although these may be biased by possibly declining selectivity
at higher ages).

Management implications:

There should be preliminary quantitative assessment later this year. Consideration may have to be given to
altered management arrangements depending on the outcome of the stock structure study currently in
progress. There are suggestions from size structure data that ling east of Bass Strait are more heavily fished
than those west of Bass Strait.

Research priorities:

A quantitative assessment will be undertaken in 1999/2000. Some aspects of harvest strategies will be
evaluated in the eastern sector (robust harvest strategies project). There are plans for a follow-up workshop
later this year. As quota transferability between the trawl and non-trawl sectors is occurring and gear
selectivity differs, the biological implications of a possible shift in catch between sectors should be
considered in harvest strategies. The implications of the stock structure research should be evaluated.




xvi                                                             SEF Fishery Assessment Report 1999
Mirror dory Zenopsis nebulosus

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total catch was 426t (413t Commonwealth, 13t State). The catch from Commonwealth
waters represented 43% of the actual TAC of 962t and 52% of the agreed TAC of 800t. The 1999 agreed
TAC is 800t, with an actual TAC of 960t.

1999 assessment:

There is no quantitative assessment for this species.

Unstandardized catch rates have generally declined for this species. There is a long time series of length
frequency data for mirror dory, but it is very variable and shows no long term trend.

The co-occurrence of mirror dory with eastern gemfish has caused difficulty in filling mirror dory quota
without exceeding trip limits on gemfish. The TAC for mirror dory has been set at the highest historical
catch level, which was taken as a by-catch of unrestricted fishing for gemfish. The eastern gemfish TAC
was set to zero during 1993 to 1996, and the resulting shift in targeting practices influenced mirror dory
catch rates. In 1997, when there was a 1000t TAC for eastern gemfish, catch and catch-rate of mirror dory
improved. In 1998, catches of mirror dory decreased along with the reduction of the eastern gemfish TAC
to 300t. Total landings were again well below (43%) the actual TAC, and it appears this situation will
continue while the eastern gemfish TAC remains low, despite increased landings west of Bass Strait in
recent years. Discarding of small mirror dory continues to be significant to the east of Bass Strait. Stock
status remains unknown.

Management implications:

Catches are likely to remain low under restrictive TACs for eastern gemfish.

Research priorities:

Standardize catch rates taking into account gemfish catches.




SEF Fishery Assessment Report 1999                                                                    xvii
Ocean perch Helicolensus sp.

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 363t (351t Commonwealth, 12t State). The catch from Commonwealth waters
represented 60% of the actual TAC of 587t and 70% of the agreed TAC of 500t. The 1999 agreed TAC is
500t, with an actual TAC of 593t.

1999 assessment:

There was no formal quantitative assessment of ocean perch in 1999.

The TAC includes two distinct species, an inshore species Helicolenus percoides (also known as coral cod)
and an offshore species H. barathri. The FRV Kapala survey indicated a significant decline in offshore
ocean perch abundance on the trawl grounds off NSW occurred between 1976/77 and 1979/81. However,
such a reduction in the early years of a virgin fishery often occurs. The survey results suggest that a further
decline in abundance occurred between 1979/81 and 1996/97. The reasons for this are uncertain. There is
little evidence of a decrease in the size of the offshore form in commercial catches, but the FRV Kapala
survey data showed a significant decline in length composition since 1976/77. Since 1995 mean
unstandardized catch rates have triggered AFMA‘s catch rate performance criterion. This was again the
case in 1998. It is unknown if the decline in catch rates is associated with declining ocean perch abundance.
Because most of the ocean perch catch is discarded, particularly the inshore species (57%), the actual catch,
compared to landings, has reached or exceeded recent TACs. The status of ocean perch stocks is uncertain
but the high level of discarding remains of concern.

Management implications:

High rates of discarding are a concern.

Research priorities:

Catch rates and length frequencies should be examined by depth.




xviii                                                           SEF Fishery Assessment Report 1999
Orange roughy Hoplostethus atlanticus

Assessment or working group:      ORAG

Recent workshops: Two meetings of ORAG in the past year

Previous quantitative assessment: 1997 assessment (not accepted by industry)

1998 fishery:

The 1998 SEF2 total for the Eastern Management Zone was 1968t, which represented 103% of the actual
TAC of 1909t and 98% of the agreed TAC of 2000t. The 1998 SEF2 total for the Southern Management
Zone was 250t, which represented 25 % of the actual and agreed TACs of 1000t. The 1998 SEF2 total for
the Western Management Zone was 360t, which represented 19% of the actual TAC of 1933t and 24% of
the agreed TAC of 1500t. The 1998 SEF2 total for the Cascade Plateau was 1560t, which represented 98 %
of the agreed TAC of 1000t. All orange roughy is caught in Commonwealth waters.


Fishing on the South Tasman Rise (which straddles the Australian EEZ and International waters) developed
strongly in 1997. Total Australian catch in 1997 (January 1 to December 17) was 1668t, while the New
Zealand catch was 430 t. From January 1 to March 1998 the Australian catch was 2052t. An annual TAC of
1669 t for Australian operators and 431t for New Zealand operators was introduced for the year starting
March 1998. Total Australian catch for the year was as 3,054t; combined catch was 3508t. In 1999, the
Australian catch in April was 1723t, and the fishery closed. New Zealand vessels continued fishing until
June 2, catching at least 1620t, greatly exceeding their quota.



1999 assessment:

No new quantitative assessment was undertaken in 1998 or 1999.

Assessment efforts during 1998/99 were spent on:
 reanalysis of acoustic data to reduce dependence on assumptions of species composition;
 addressing questions raised by the apparent (and unexpected) 20 year decline in modal age between
    1992 and 1995, including ageing of earlier otolith samples;
 rewriting the assessment model as a full Bayesian analysis to account for alternative data and
    functional hypotheses;
 updating and improving analyses of catch rates in the various management zones and sub-areas; and
 undertaking a new acoustic survey for St Helens, including the evaluation of industry acoustic survey
    techniques.

Indicators by management zone:

Eastern Zone: standardized catch rates and acoustic surveys have shown a decline over the course of the
fishery but TACs have been caught in all years. Catch rates at St Helens have increased slightly since 1996.

Southern Zone: standardized catch rates have fallen to very low levels and recent catches are well below
TAC levels.

Western Zone: standardized catch rates have fallen to low levels and recent catches are well below TAC
levels.

Cascade Plateau: there are no trends in catch rates (too short a history). Preliminary acoustic surveys may
be undertaken in 1999. A spawning aggregation has been found, and the suggestion has been put forward to
close the spawning aggregation to fishing in the future.

South Tasman Rise: there are no trends in catch rates (too short a history). Preliminary acoustic surveys
may be undertaken in 1999. Research on stock structure is nearing completion.


SEF Fishery Assessment Report 1999                                                                      xix
Key uncertainties in the E/S/W management zones include stock structure issues, changes in age and length
structure over time in the East and South, and questions about the within-season dynamics of the St Helens
spawning aggregation.

Management implications:

There are clear concerns about catch rates in the Southern and Western management zones. The need for
changes to catch levels in the eastern zone should be clearer following the 1999 survey and the 2000
assessment. The Cascade and South Tasman Rise fisheries should continue to be closely monitored.

Research priorities:

Quantitative assessments will be undertaken during 1999/2000 for the eastern, southern and western
management zones. Development of an industry deepwater acoustic capability will, if successful, provide
initial biomass estimates for the Cascade Plateau. Preliminary quantitative assessments may be undertaken
for the Cascade and South Tasman Rise fisheries, depending on availability of data. ORAG also needs to
consider whether an assessment can be undertaken for the Eastern A/B and Lord Howe Rise management
area. A strategic research and assessment plan has been developed by ORAG for Australia‘s orange roughy
fisheries and is currently being circulated among fishers for comment. Ageing of recent otolith collections
should be undertaken.




xx                                                            SEF Fishery Assessment Report 1999
Redfish Centroberyx affinis
Assessment or working group:       RAG

Recent workshops: Three meetings of the RAG in the past year.

Previous quantitative assessment: 1998 RAG assessment

1998 fishery:
The 1998 SEF2 total was 1770 t (1752 t Commonwealth; 18 t State). The catch from Commonwealth
waters represented 86% of the actual TAC of 2042 t, and 100% of the agreed TAC of 1750 t. The 1999
agreed TAC is 1750 t, with the actual TAC being 1941 t. Landings reported in 1997-98 by NSW trawlers
north of 33°S were 13t.

1999 assessment:

Recent redfish assessments commenced with a workshop in 1993, which identified deficiencies in data
quality concerning the quantities and size composition of discards, and the growth of redfish. This was
followed by a period of improved data collection by onboard observers (1993 to present) and an increase in
the number of redfish aged by the CAF (total aged > 5000). A further workshop (April, 1997) reviewed the
new data, and was followed by the formation of the Redfish Assessment Group (RAG).

The RAG incorporated industry advice on historical discard practices in an estimation of the total catch of
redfish from 1960 to 1992, after which data from onboard observers were used to describe the total catch.
The RAG produced an initial quantitative assessment of the status of the redfish stock (based on a cohort
analysis) in 1998. This entailed constructing a history of catch at age data from historical length frequency
data and a pooled age-length key. Comments made on this initial assessment at the 1998 SEFAG plenary
meeting were incorporated in the updated assessment completed by the RAG in 1999.

The 'standard' catch rate index adopted by the RAG increased in the early 1990s after being low in the late
1980s, then declined again until 1996 and increased in 1997 and 1998. It is uncertain how well this catch
rate indexes abundance.

Cohort analyses using two historical catch scenarios produced estimates of 'unexploited' biomass of 38 - 54
thousand tonnes, and indicated steady declines in recruited biomass until the early 1990s when improved
recruitment slowed the decline. Estimates of recent/current biomass are highly sensitive to the 'tuning
period' used in the cohort analysis, and range from 3 to 10 thousand tonnes.

The mean length of redfish in the landed catch continues a long term decline, and is now less than 20 cm
LCF.

Key uncertainties in the assessment include the levels of historical discarding, the back projections of catch
at age, and sensitivities to the tuning indices and to estimates of natural mortality.

Management implications:

There is evidence of ―growth overfishing‖ for this species. This means that fish are being caught at a
smaller size and younger age than the size or age that would maximize the harvest from the resource. This
issue will be addressed in part in the ―bycatch‖ project currently underway.

Estimates of current depletion range from 7 to 25% of unfished biomass. However there are still major
uncertainties to resolve in the assessment. There is evidence from previous experience that reducing the
TAC will not necessarily lead to reductions in catch, but more likely to increases in discarding.

Research priorities:

The RAG should continue. An acoustic survey feasibility study will be undertaken in 1999. A pre-proposal
has been submitted to apply alternative modelling methods for the redfish assessment using a ―synthesis‖
model.


SEF Fishery Assessment Report 1999                                                                        xxi
Royal red prawn Haliporoides sibogae

Assessment or working group:      None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 282t (214t Commonwealth, 68t State). The catch from Commonwealth waters
represented 34% of the actual TAC of 625t and 43% of the agreed TAC of 500t. The 1999 agreed TAC is
500t, with an actual TAC of 611t.

1999 assessment:

There was no formal quantitative assessment of royal red prawn in 1999.

Royal red prawn comprise a common stock off NSW that straddles the Barrenjoey line. A significant
amount of the SEF2 catch is reported as coming from State waters north of the Barrenjoey line.
Complementary management controls are not yet in place for this species. Targeting of royal red prawn is
market driven. Mean undstandardised catch rates have exhibited a general decline since 1980, and in 1998
they triggered AFMA‘s catch rate performance criterion for the first time. Stock status remains unknown.

Management implications:

The use of sweeps on RRP nets is currently under review by SETMAC. NSW is introducing mandatory
BRDs into the fishery north of Barrenjoey.

Research priorities:

Data on discards has started to be collected by the ISMP.




xxii                                                         SEF Fishery Assessment Report 1999
Silver trevally Pseudocaranx dentex

Assessment or working group:       None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 233t (100t Commonwealth, 133t State). The catch from
Commonwealth waters represented 16% of the actual TAC of 601t. However
Commonwealth SEF catches are less than 20% of the total catch for this species.

1999 assessment:

Preliminary research suggests that the silver trevally off southeast Australia represent a single stock that is
distinct from the North Island of New Zealand fishery. Whereas silver trevally growth rates are slower than
those reported for New Zealand, the Australian stock matures comparatively early at about two years of
age. The oldest Australian fish aged so far is less than half the age of the oldest New Zealand fish (47
years), but large fish (>60cm) have yet to be sampled. No assessment has been undertaken since 1994 and
there is no previous quantitative assessment. Despite declining catches since 1995, mean unstandardised
catch rates have remained relatively stable since 1991. Because much of the SEF catch is genuinely taken
from State waters and no State trip-limit applies to this species, the TAC does little to constrain the overall
SEF catch. Significant catches are also taken north of the SEF boundary and by recreational fishers. Stock
status remains unknown.

Management implications:

Commonwealth catches are a small fraction of total catches for this species.

Research priorities:

A research program is currently underway in NSW to provide information for assessment of the silver
trevally stock and an initial assessment is due in early 2000.




SEF Fishery Assessment Report 1999                                                                       xxiii
Spotted warehou Seriolella punctata

Assessment or working group:        None

Recent workshops: None

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 total was 2411t (2410t Commonwealth, 1t State). The catch from
Commonwealth waters represented 71% of the actual TAC of 3383t and 69% of the agreed
TAC of 3500t. The 1999 agreed TAC is 4000t, with an actual TAC of 4537t. The non-trawl
mesh sector also caught 169t in 1997, while catches in 1998 were 66t.

1999 assessment:

There is no quantitative assessment for this species.

Catches have been at historically high but stable levels since 1994. There are no clear trends
in (unstandardized) catch rates, but any signals may be masked by changes in targeting,
increases in by-catch as a result of increased catches of blue grenadier, changes in depth of
fishing etc. There are very high discard rates for this species in Western Tasmania and the
Western Zone of the fishery. It is not clear if this may be market or quota driven.

There is evidence from catch composition data to suggest that a strong cohort entered the
population probably in 1994. It is currently impossible to assess the size of this cohort
quantitatively due to the lack of a detailed stock assessment. However, it is reasonable to
conclude that the fishable biomass may have increased in the short-term (1-2 years)
following it first appearing in catches in 1996. A subsequent decline might be expected as
the increase in stock biomass due to growth of the cohort is outweighed by decline in
biomass due to natural and fishing mortality. One of the implications of a strong cohort
entering the population is that there is potential scope for increased catches in the short-term.
This may indeed account for recent strong catches of this species. However, the lack of a
quantitative stock assessment precludes an evaluation of the risks associated with different
levels of possible catches. Increased catches of spotted warehou have implications for blue
warehou by-catch as the two species commonly occur together. The priority for research on
this species should be increased given the high current catch, the increase in targeting by the
non-trawl (mesh) sector and the fact that a market for this species appears to be developing.
A substantial proportion of the catch of juveniles is discarded.

Management implications:

There appears to be at least one strong year class passing through the fishery at the moment. Stock
assessment is a very high priority for this species.

Research priorities:

There is a suggestion that spotted warehou could be the third species selected under the ―three species‖
stock assessment project currently run by CSIRO (the first two species are blue grenadier and ling). There
is a research pre-proposal to hold a workshop on this species. This workshop should examine, among other
issues, targeting and depth effects on catch rates.




xxiv                                                             SEF Fishery Assessment Report 1999
School whiting Sillago flindersi

Assessment or working group:        None

Recent workshops: June 1999

Previous quantitative assessment: None

1998 fishery:

The 1998 SEF2 landed weight of school whiting was 639 t (419 t in Commonwealth waters and 220 t in
State waters), which was 26% of the allocated TAC of 2,423 t. It represents a decrease in landings
compared to 1997 (754 t). The 1999 TAC was reduced to 1500 t, with the allocated TAC being 1,929 t.

1999 assessment:

The 1999 assessment is based on the first formal stock assessment of school whiting in the SEF. The
assessment uses catch-at-age and fishing effort data. The SEF stock that has been assessed extends from
Jervis Bay to Portland.

About 95% of the school whiting catch is taken by Danish seiners with Lakes Entrance the
major port. Mean unstandardised catch rates by Danish seiners are extremely variable but
were lower in 1996-98 than for the period 1986-94 upon which AFMA‘s catch rate
performance criterion is based. Standardised CPUE showed a similar pattern. However, the
implications of these data alone should be treated cautiously. Annual catches of whiting are
influenced by several factors including market demand and the effort directed by the fleet at
flathead. Catch statistics show that annual catches of whiting and flathead are inversely
related and in recent years the effort in flathead depths has increased.

Industry stressed that the decline seen in catches and catch rates did not reflect declining abundance but was
due to market and environmental factors. In addition, they argued that the widespread prevalence of algae
in the region reduced their ability to fish for whiting and effected the quality of fish and their suitability for
export. Fishermen noted that catches and catch rates in 1999 were higher than in recent years. It was further
pointed out by Lakes Entrance fishermen that the size of the Danish seine fleet has reduced considerably
since 1992 from over 20 to 15.

Between 1991 and 1998 the size and age compositions of school whiting landings were relatively stable
with no trends indicating decreasing abundance or increased fishing mortality. The estimates of and
uncertainty regarding spawner biomass are sensitive to the method used for incorporating the catch-at-age
data in the analysis. However, the qualitative results of the assessment suggest relative (though uncertain)
stability for the spawner biomass.

Despite the advance made in assessing school whiting this year, no attempt was made to conduct stock
projections. The reasons for this were the uncertainty with which biomass could be estimated and the lack
of a process for defining appropriate performance indicators. Extension of the assessment to include data
from earlier years and a risk assessment based on projections of alternate TACs is recommended.

Management implications:

Results from the first quantitative assessment suggest that the biomass has been relatively stable in recent
years. The reason for the apparent decline in catch rates is unclear but could be due to several factors
mentioned above. The implications of the assessment are considerably less pessimistic than in recent years.

Research priorities:

Finalize the stock assessment using more of the historical size structure data and historical survey data.
Examine the implications of future catch levels.



SEF Fishery Assessment Report 1999                                                                           xxv
ECONOMIC SUMMARY
The gross value of production of catches taken by Commonwealth trawlers in 1998 is estimated to be $56.4
million, 6 per cent lower than in 1997. This decrease is mainly due to the decrease in landings of orange
roughy. In the Commonwealth non-trawl sector of the fishery, the value of blue eye trevalla, ling and blue
warehou was around $3.5 million in 1998. Landings of other fish species (excluding shark) by this sector
for 1998 were valued at $x million.
The financial performance of the trawl component of the fishery was assessed in 1997, covering the period
1994-95, 1995-96 and 1996-97. Prior to 1996-97 there were substantial declines in average boat profit
across the fleet. However, average boat profit is estimated to have risen 79 per cent to $45 400 in 1996-97.
This recovery is estimated to have occurred across all sectors of the fleet.
While there has been a short term improvement in the profitability of the fishery, the longer term trends are
not so promising. Although permanent quota trading has been permitted since 1994, this does not appear to
have resulted in full fleet adjustment in this multi-species fishery. Long run rates of return would be
expected to have improved under an effective ITQ management with rationalisation of boat capital and
fishing effort. The introduction of ITQs has had different impacts on the profitability of the various fleet
sectors.
While a number of problems in the ITQ scheme have been or are being addressed, such as those pertaining
to jurisdictional arrangements and the non inclusion of the non trawl sector, there are substantial concerns
about the effectiveness of the ITQ scheme. These include the observed systematic short fall in the fish catch
relative to the total allowable catch for many quota species, the continuing increase in fishing effort, the
estimated high levels of discarding for some species and the limited trade in quota.




xxvi                                                            SEF Fishery Assessment Report 1999
ACKNOWLEDGMENTS
This report was prepared by South East Fishery Assessment Group (SEFAG). The report is a compilation
of the contributions by several members of the SEFAG and reflects their input at the time of production
(July 1998). The resources of a wide range of agencies have been used in this process and their support,
especially from State fishery agencies and CSIRO, is gratefully acknowledged, as is the contribution of
industry members. The Australian Fisheries Management Authority (AFMA), through the AFMA Research
Fund (ARF), funded the coordination activities of the group. John Garvey (BRS) revised the figures in this
report and supplied much aggregated SEF1 data to SEFAG. The report is based on Stock Assessment
Reports (SARs) of the quota species listed below and revision of the other quota species using 1998
fisheries data. The full Stock Assessment Reports have been, or will be, published as separate documents.
The work of the following authors and Assessment Groups on the 1998 SARs is greatly appreciated.
     Blue grenadier          David Smith (MAFRI Victoria) (Chair BGAG)
     Blue warehou            David Smith (MAFRI Victoria) (Chair BWAG)
     Gemfish eastern         Tony Smith (CSIRO) (Chair EGAG)
     Orange roughy           Nic Bax (CSIRO) (Chair ORAG)
     Redfish                 Jean Chesson (BRS) & Kevin Rowling (FRI) (Chair RAG)
     Economic Report         Deborah Brown (ABARE)

Revision of existing Stock Assessment Reports and provision of summaries was undertaken by the
following authors, or the Group;
     Blue eye trevalla       Pascale Baelde (Consultant)
     Flathead                Ian Knuckey (MAFRI)
     Gemfish western         Richard Tilzey (BRS)
     Jackass morwong         Ian Knuckey (MAFRI)
     John dory               Richard Tilzey (BRS)
     Ling                    Richard Tilzey (BRS)
     Mirror dory             Ian Knuckey (MAFRI)
     Ocean Perch             Richard Tilzey (BRS)
     Royal Red Prawn         Richard Tilzey (BRS)
     School Whiting          Ian Knuckey (MAFRI)
     Silver Trevally         Richard Tilzey (BRS)
     Spotted warehou         Ian Knuckey (MAFRI)

A review of the Stock Assessment Reports and species summaries was provided at the annual SEFAG
Plenary meeting held at the AFMA, Canberra, on July 6-10 1998. This Fishery Assessment Report was also
developed at this meeting and builds upon earlier reports (Chesson 1996, 1997, Tilzey 1998). Participants,
many whom were only present for part of the meeting, are listed below. Core members of the 1998 SEFAG
are in bold type.
     Dr David Alden (AFMA)
     Dr Nic Bax (CSIRO) (not at plenary)
     Dr Pascale Baelde (Consultant)
     Ms Deborah Brown (ABARE)
     Mr Peter Bell (Industry)
     Mr Steve Dixon (AFMA)
     Mr Horst Fischer (Industry)
     Mr Jon Harford (AFMA)
     Mr Anthony Jubb (Industry)
     Mr Neil Kelly (Industry)
     Dr Ian Knuckey (MAFRI, Victoria) (not at plenary)
     Mr Rocky Lagana (Industry)
     Mr Joe Lavelle (Industry)
     Dr Jeremy Lyle (Tasmanian DPIF)
     Ms Katrina Maguire (AFMA)
     Mr Michael Mariklis (Industry)
     Mr Ryan Murphy (AFMA) (Secretary)
     Dr Jeremy Prince (Industry Consultant)


SEF Fishery Assessment Report 1999                                                                   xxvii
    Dr Andre Punt (CSIRO)
    Mr Kevin Rowling (NSW FRI)
    Mr John Sealey (Industry)
    Mr Les Scott (Industry)
    Mr Tony Shelton (Industry)
    Dr David Smith (MAFRI Victoria)
    Dr Tony Smith (CSIRO)
    Ms Miriana Sporcic (MAFRI Victoria)
    Dr Derek Staples (BRS)
    Mr Richard Tilzey (BRS) Chair




xxviii                                    SEF Fishery Assessment Report 1999
LIST OF ABBREVIATIONS
    ABARE         Australian Bureau of Agriculture and Resource Economics
    AEP           annual egg production
    AFMA          Australian Fisheries Management Authority
    AFZ           Australian Fishing Zone
    AFZIS         Australian Fishing Zone Information System
    ANCA          Australian Nature Conservation Agency
    ARF           AFMA Research Fund
    BGAG          Blue Grenadier Assessment Group
    BWAG          Blue Warehou Assessment Group
    BRS           Bureau of Resource Sciences
    CAF           Central Ageing Facility (Vic)
    CPUE          catch per unit effort
    CSIRO         Commonwealth Scientific and Industrial Research Organisation
    CV            coefficient of variation
    DPFRG         Demersal and Pelagic Fish Research Group (sub-committee of
                  Standing Committee on Fisheries and Aquaculture, disbanded
                  1995)
    DPIF / TDPIF  Tasmanian Department of Primary Industry and Fisheries
    EA            Environment Australia
    EGAG          Eastern Gemfish Assessment Group
    ESD           Ecologically Sustainable Development
    FAGs          Fisheries Assessment Groups
    FEM           Fisheries Ecosystem Management
    FRDC          Fisheries Research and Development Corporation
    FRI           Fisheries Research Institute (Cronulla, NSW)
    FRRF          Fisheries Resources Research Fund
    GAB           Great Australian Bight
    GABTF         GAB Trawl Fishery
    GLM           generalised linear model
    GNO1          South East Non-trawl and Southern Shark general logbook
    GPS           global positioning system
    GVP           Gross Value of Production
    ISMP          Integrated Scientific Monitoring Program (established in 1996 as
                  the successor to the Scientific Monitoring Program)
    ITQ           individual transferable quota
    LCF           (fish) length at caudal fork
    LRP           limit reference point
    MAF           Ministry of Agriculture and Fisheries (NZ)
    MAFRI         Marine and Freshwater Research Institute (Victoria)
    MARPOL        International Convention for the Prevention of Pollution from
                  Ships (MARine POLution convention)
    MSY           Maximum sustainable yield
    NSW           New South Wales
    NTCC          Non Trawl Consultative Committee
    OC            Organochlorine
    OCS           Offshore Constitutional Settlement
    ORAG          Orange Roughy Assessment Group
    OTC           Oxytetracycline
    QMS           Quota Monitoring System (AFMA)
    RAG           Redfish Assessment Group
    SA            South Australia
    SAR           Stock Assessment Report
    SEF           South East Fishery
    SEF1          South East Trawl Fishery logbook records
    SEF2          South East Trawl Fishery landed catch records
    SEFAG         South East Fishery Assessment Group
    SEFNTCC       South East Fishery Non-Trawl Consultative Committee


SEF Fishery Assessment Report 1999                                                   xxix
      SENT             South East Non-trawl (Fishery)
      SENTA            South East Non-trawl Association
      SENTMAC          South East Non-Trawl Management Advisory Committee
      SET              South East Trawl (Fishery)
      SETFIA           South East Trawl Fishing Industry Association
      SETMAC           South East Trawl Management Advisory Committee
      SFM              Sydney Fish Market
      SMP              Scientific Monitoring Program
      TAC              total allowable catch
      TL               total (fish) length
      TPWS             Tasmanian Parks and Wildlife Service
      VFRI / Vic FRI   Victorian Fisheries Research Institute (became part of MAFRI in
                       July 1996)
      VPA              virtual population analysis




xxx                                                       SEF Fishery Assessment Report 1999
INTRODUCTION
This report is produced by the South East Fishery Assessment Group (SEFAG) under the fishery
assessment process initiated by the Australian Fisheries Management Authority (AFMA).
Each year SEFAG produces a Fishery Assessment Report summarising information for the entire SEF.
More detailed individual Stock Assessment Reports (SARs) for selected species within the fishery are also
periodically produced. The production of SARs is increasingly the responsibility of individual Fishery
Assessment Groups (FAGs) operating under the SEFAG ―umbrella‖. In 1997/98, FAGs were active for 5
quota species; blue grenadier (BGAG), blue warehou (BWAG), eastern gemfish (EGAG), orange roughy
(ORAG) and redfish (RAG). The content and format of the reports produced are standardised across
fisheries and this report conforms to those standards. All headings are retained, even if no data exist for a
given category.
The report begins with the Fishery Assessment and is followed by summaries of individual species based on
the most recent SARs. More detailed information on each species can be obtained by referring to the
individual SARs, which are not produced for all quota species every year, but according to species priority
and the amount of new information. A list of SARs is given below.
The Fishery Assessment Report includes tables of catch history (Appendix A) and tables of biological and
fishery parameters (Appendix B) with each species summary. Since a Stock Assessment Report is not
produced every year for all species, the tables have been included in the Fishery Assessment Report to
record the most recent data.
Statements of AFMA's objectives, strategy and performance criteria for each species were provided by
AFMA and are repeated verbatim.
Record of individual SEFAG Stock Assessment Reports

 Species                      Scientific name                                 Years in which a Stock
                                                                              Assessment Report has been
                                                                              produced
 Blue eye trevalla            Hyperoglyphe antarctica                         1994, 1995, 1997
 Blue grenadier               Macruronus novaezelandiae                       1994, 1995, 1997, 1998
 Blue warehou                 Seriolella brama                                1994, 1995, 1996, 1997, 1998
 Flathead                     Neoplatycephalus richardsoni,                   1994, 1996
                              Platycephalus bassensis, Neoplatycephalus sp.
 Gemfish, eastern             Rexea solandri (eastern stock)                  1994, 1995, 1996, 1997, 1998
 Gemfish, western             Rexea solandri (western stock)                  1994, 1997
 Jackass morwong              Nemadactylus macropterus                        1994, 1995, 1997
 John dory                    Zeus faber                                      1994, 1996
 King dory                    Cyttus traversi                                 1995
 Ling                         Genypterus blacodes                             1994, 1995
 Mirror dory                  Zenopsis nebulosus                              1994, 1996, 1997
 Ocean perch                  Helicolenus sp.                                 1994, 1996
 Orange roughy                Hoplostethus atlanticus                         1994, 1995, 1996, 1997 1998
 Redfish                      Centroberyx affinis                             1993, 1994, 1995, 1997, 1998
 Royal red prawn              Haliporoides sibogae                            1994
 School whiting               Sillago flindersi                               1994
 Silver trevally              Pseudocaranx dentex                             1994
 Spotted warehou              Seriolella punctata                             1994




SEF Fishery Assessment Report 1999                                                                              1
SOUTH EAST FISHERY ASSESSMENT
1.     THE FISHERY
The ―South East Fishery‖ is a multi-species fishery situated off the south east coast of Australia.
The trawl sector of the fishery extends southward from Barrenjoey Point in NSW around Victoria and
Tasmania and west to Cape Jervis in South Australia. The main harvesting method is otter trawling,
although a Danish seine fleet operating primarily out of Lakes Entrance, Victoria, also forms an important
part of the fishery.
The non-trawl sector of the fishery extends southwards from Fraser Island, off Queensland, around NSW,
Victoria, Tasmania and South Australia. Off New South Wales and Queensland, waters out to about 80
nautical miles (nm) are under State jurisdiction except Purse Seine, which is Commonwealth managed
outside 3 nm from New South Wales. The main harvesting methods are drop-lining and demersal long-
lining and gillnetting.
The SEF is managed by the Commonwealth (AFMA) using output controls in the form of Total Allowable
Catches (TACs) apportioned as Individual Transferable Quotas (ITQs). These management controls were
introduced for the 16 major species or species-groups in the trawl fishery in 1992. Periodic stock
assessment is an integral part of the annual TAC-setting process. Therefore, there is an inevitable emphasis
on those species subject to quota in this report. Until 1998, ITQ management only applied to
Commonwealth endorsed trawlers and Danish seiners within the SEF boundaries (Figure 1). Because
significant catches of blue-eye trevalla, blue warehou and ling are also made by commercial fishers using
methods other than trawl or Danish seine, ITQ management of these species was expanded to the non-trawl
sector at the start of 1998. The assessments in this report consider mortality from all types of fishing,
including catches outside the SEF boundaries, where information is available. However, the values below
are only for Commonwealth endorsed vessels.
MAIN FEATURES
Trawl sector
     Catch composition:      see principal species
     Value:                  $46.8 million quota and $9.6 million non-quota (1998);
                             including catches from the Remote Zone
     Fleet:                  inshore trawlers; deepwater trawlers; Danish seiners
     Fishing permits (1997): 150 (42 inactive) (December 1996a)
     Quota holders (1997): 108 seasonal quota holders (December 1996)
     Bait source:            not applicable
     By-catch:               many fish species of varying commercial value
     Discards:               major issue for several quota species, especially
                             bluegrenadier, redfish, ocean perch, flathead and eastern
                             gemfish
Non-Trawl sector
     Catch composition:             blue eye trevalla, blue warehou and ling are the principal
                                    species
     Value:                         $3.5 million (1998) quota and $xx million non-quota.
     Fleet:                         primarily dropline, demersal longline/setline and gillnet
                                    operators
     Fishing permits:               155 eligible operators
     Bait source:                   mainly SEF where applicable
     By-catch:                      dependent on targeting practices: usually low levels for line
                                    methods; a range of species of varying commercial value
                                    taken by gill nets
     Discards:                      unknown
                                    a
                                        27 permits were removed via an adjustment scheme in 1997



2                                                                 SEF Fishery Assessment Report 1999
      NOTE To Printer - this page will be printed by AFMA - full page colour map.

Figure 1. Geographical boundaries of the South East Fishery.




SEF Fishery Assessment Report 1999                                                  3
PRINCIPAL SPECIES
Trawl Sector
Over one hundred species of finfish and invertebrates are routinely landed in the South East Fishery (SEF).
However, some ten species constitute more than 80 per cent of the landed trawl tonnage and one species,
orange roughy, constituted 18 per cent of the landed weight in 1998. The contribution of orange roughy has
fallen markedly from 77 per cent by weight in 1990 and will continue to do so as this fishery declines.
In the trawl sector, 16 species (or species groups) are currently managed by using TACs and ITQs and this
report covers those species. Eastern and western gemfish are known to be distinct stocks and are reported
separately.
The 16 quota species (or species groups) are extremely diverse, ranging from mid-water predators to
inshore, mid-shelf and upper slope demersal species. Some SEF species are caught in a few metres depth
(e.g. flathead, school whiting); others (e.g. orange roughy, oreo dories) comprise some of the world's
deepest commercial trawl fisheries extending down to 1300 metres.
Non-trawl Sector
As in the trawl sector, a wide range of species is landed by non-trawl methods in the SEF. However, the key
non-trawl species of blue-eye trevalla, ling and blue warehou comprise the major part of the catch, with the
latter two also being important trawl species. These three key species are currently managed by using TACs
and ITQs, and are, to a large extent, the only species commonly targeted by Commonwealth endorsed non-
trawl fishers within the SEF. (However, many of these fishers also operate in other fisheries such as the
Southern Shark Fishery). Hapuku (Polyprion oxygeneios), bass grouper (P. moeone), dogsharks, gemfish,
ling, redfish, ocean perch, blue grenadier and Ray‘s bream (Brama brama) are a common bycatch of drop-
liners targeting blue-eye trevalla. Other species commonly taken by demersal gillnetters include spotted
warehou, boarfish (various species) and silver trevally. By the year 2000 ITQ management of the 16 quota
species will also apply to the the non-trawl sector.

BOUNDARIES
Ecological
The fishery encompasses different ecosystems and many habitats from the shallow waters of the continental
shelf to slope waters down to 1500 metres depth, including deepwater seamounts. Many species taken
routinely in the SEF have distributions that extend well beyond the SEF management boundaries.
Reconciliation of the biological and management boundaries for the SEF is considered a high priority by
researchers and managers.
Management
Management boundaries for the trawl sector (Figure 2) extend in a line east from Barrenjoey Point, NSW to
a line south from Cape Jervis, SA and include waters around Tasmania. SEF waters extend from a distance
3 nm offshore (the limit of State managed waters) to the 200 nm limit of the Australian Fishing Zone
(AFZ), except where this is varied by an Offshore Constitutional Settlement (OCS) agreement.
Before ITQ management, the trawl fishery was originally divided into three Sectors (Eastern A, Eastern B
and Southwest) with different limited entry requirements. More recently, the orange roughy and gemfish
fisheries have been given distinct management zones (Figure 2). Orange roughy caught outside these zones
are not subject to ITQ management, although TACs are in place for the Cascade Plateau and South Tasman
Rise. The western zone is also the management zone for western gemfish, with gemfish caught outside this
zone being deemed eastern gemfish.
The area of the non-trawl fishery takes in all waters of the Australian Fishing Zone (AFZ) off South
Australia, Victoria and Tasmania up to the low water mark, and Commonwealth managed waters of the
AFZ off southern Queensland (to Sandy Cape) and New South Wales which lie outside a line drawn
approximately 80 nm from the coast (except for SENTF purse seining for scale fish off New South Wales,
which is Commonwealth managed outside 3 nm).
Statistical
To examine and monitor of spatial aspects of the trawl sector fishery, it has been divided into six statistical
regions which approximate the distributions of the six regional demersal shelf/upper slope fisheries within
the SEF (Klaer and Tilzey 1994), as shown in Figure 3.


4                                                                SEF Fishery Assessment Report 1999
Figure 2. Management boundaries of the South East Fishery as currently defined for the trawl sector, including
orange roughy management zones (adapted from Tilzey 1994)




Figure 3   South East Fishery statistical zones for the trawl sector (Klaer & Tilzey 1994)




SEF Fishery Assessment Report 1999                                                                               5
STOCKS AND AREAS
All quota species in the SEF, except orange roughy and gemfish, are currently managed as single stocks.
That is, management decisions for a given species are applied across the entire SEF, rather than having
requirements tailored specifically for different fish populations or geographic regions.
Information from targeted stock structure studies is available only for gemfish, blue grenadier, whiting, blue
eye trevalla and orange roughy. Eastern and western gemfish are considered to be distinct stocks within the
SEF, although the taxonomic status of the latter in the western limit of its distribution off Western Australia
is unclear. Blue grenadier distribution extends from NSW to Western Australia and genetic studies indicate
a single stock in these waters. Three stocks of school whiting are known for the SEF, with virtually all
quota catches coming from the central ―Jervis Bay to Portland‖ stock. Recent genetic studies indicate a
single Australian stock of blue eye trevalla. Considerable research has been directed at orange roughy
stock structure. Although there may be one genetic population of orange roughy in the SEF, there is
suggestion of some stock structuring based on parasite loadings, otolith chemistry and other biological
information. These data are consistent in suggesting a difference between stocks off NSW and eastern
Tasmania. Recent analyses of otolith morphometrics support the possibility of a common migratory stock in
the Eastern and Southern Management Zones, from which the mature adults seasonally aggregate at the St
Helens spawning site.
Tagging studies of redfish off NSW indicated a single stock, but recent growth analyses suggest significant
difference between fish off Ulladulla and Eden that may be indicative of stock structuring. Although recent
otolith microchemistry studies indicate that there may be three separate stocks of jackass morwong off
southern Australia (in the Great Australian Bight, off Tasmania south of Bass Strait and in waters off
Victoria and NSW including Bass Strait), genetic studies suggest a common stock within the SEF. A pilot
study on silver trevally suggests a single stock for south-eastern Australia, although some regional
structuring is evident. Preliminary results from an ongoing CSIRO morphometric/genetic study of ling
suggest some stock structuring within the SEF
 For most other species in the SEF, targeted studies of stock structure have not been undertaken. The
CSIRO has recently reviewed the taxonomy of all quota species. At the species level, at least two species
of ocean perch are grouped under a common TAC. Similarly, the flathead TAC includes four flathead
species other than tiger flathead (Daley et al 1997).
A 1993 analysis of catch (shot-by-shot) compositions and distributions recorded in the SEF logbook
indicated that there are 16 main species assemblages, or trawl sub-fisheries, within the SEF (Klaer &
Tilzey, 1994). These sub-fisheries are often seasonal. The catch within each sub-fishery is usually
composed of no more than three major species. This suggests that the SEF is composed of a comparatively
small number of (commercial) species assemblages.
Each trawl sub-fishery can be classified by its dominant species as listed below:
     Group 1:        eastern gemfish (76 per cent by weight of total group catch)
     Group 2:        blue grenadier (78 per cent)
     Group 3:        jackass morwong (49 per cent); tiger flathead (17 per cent)
     Group 4:        school whiting (77 per cent); tiger flathead (13 per cent)
     Group 5:        tiger flathead (60 per cent); jackass morwong (10 per cent); other species (11per cent)
     Group 6:        mirror dory (28 per cent); eastern gemfish (21 per cent); other species (17 per cent)
     Group 7:        ling (45 per cent); ocean perch (13 per cent); blue grenadier (11 per cent)
     Group 8:        other species (55 per cent); silver trevally (15 per cent)
     Group 9:        royal red prawn (74 per cent)
     Group 10:       redfish (59 per cent); other species (12 per cent)
     Group 11:       orange roughy (96 per cent)
     Group 12:       warehou (64 per cent)
     Group 13:       squid (45 per cent); other species (14 per cent)
     Group 14:       tiger flathead (28 per cent), other species (19 per cent) redfish(12 per cent)
     Group 15:       oreo dory (50 per cent); orange roughy (49 per cent)
     Group 16:       blue grenadier (34 per cent); ling (14 per cent); gemfish (14 per cent); other species
                     (10per cent)




6                                                               SEF Fishery Assessment Report 1999
This analysis further showed that the SEF trawl sector contains seven regional fisheries: the inner shelf
(Danish seine) fishery in northern Bass Strait; three major shelf and shelf-break fisheries off eastern New
South Wales, eastern Victoria-Bass Strait and western Victoria-Bass Strait; two minor shelf and shelf break
fisheries off eastern and western Tasmania; and an extensive upper-slope deepwater fishery.

FISHING METHODS

In the trawl sector, demersal trawling and Danish seining (including some vessels licensed to fish in State
waters only) are the dominant catching methods. Increasing interest is being shown in midwater trawling,
but the use of this method has so far been limited. The non-trawl sector includes methods such as gill-
netting, drop-lining, demersal long-lining and trapping and purse seine. Whereas the number of
Commonwealth endorsed non-trawl vessels exceeds the number of trawlers and Danish seiners, the overall
tonnage of the non-trawl fleet is much less. Many non-trawl fishers also hold licences for other fisheries and
only target SEF quota species on a seasonal basis. Recreational catches are unknown but are thought to be
significant for some SEF quota species, such as silver trevally.

BRIEF HISTORY
Trawl sector
The trawl sector of the SEF has undergone considerable change since it started in the early 1900s. The first
TACs were introduced for gemfish in 1988 and orange roughy in 1990. TACs and ITQs for the remaining
16 main commercial species (or species groups) taken by the fishery were introduced at the start of 1992.
This report concentrates on the 16 species for which quotas have been introduced.
Early fishing activities were confined to the continental shelf in depths of less than 200 m. Before 1930, tiger
flathead was the main species targeted by trawlers, but declining catches led to increasing exploitation of
jackass morwong and redfish from the late 1940s onwards. Steam trawlers dominated the fishery from 1915 to
1950, Danish seiners dominated from the early 1950s to the early 1970s, and modern otter trawlers have been
predominant since then. During the 1970s, the fishery off NSW expanded southward and out to waters deeper
than 200 m. By the early 1980s, the NSW fleet had grown to 130 vessels; almost double that of 1970.
Landings from NSW and eastern Bass Strait waters dominated the total SEF catch until the mid-1980s. Then
the discovery of commercial quantities of orange roughy in waters around Tasmania caused a marked shift of
effort to that area resulting in increases in Tasmanian and Victorian landings. Effort in the roughy fishery
peaked in 1991. More recently, there has been a marked decline in fishing in waters south of Tasmania and a
significant shift of effort to the western waters of the fishery (Figure 4). In terms of annual landed tonnage of
―market‖ species, Eden is now the major port in the fishery. However, increased landings in Hobart, of blue
grenadier from the winter fishery off western Tasmania and orange roughy from the Cascade Plateau and South
Tasman Rise, saw this port record the highest 1997 landings (Table 1).


                          50
                          45
                                                                                      Otter trawl only
   Effort ( '000 hours)




                          40
                          35
                          30
                          25
                          20
                          15
                          10
                          5
                          0
                               86
                               88
                               90
                               92
                               94
                               96
                               98
                               86
                               88
                               90
                               92
                               94
                               96
                               98
                               86
                               88
                               90
                               92
                               94
                               96
                               98
                               86
                               88
                               90
                               92
                               94
                               96
                               98
                               86
                               88
                               90
                               92
                               94
                               96
                               98
                               86
                               88
                               90
                               92
                               94
                               96
                               98




                               Eastern A   Eastern B   East'n Tas   West'n Tas   Western        Bass Strait

                                                                Year
Figure 4 Trawl fishing effort by zone, 1986 to 1998 (Data source : SEF1 logbook data)

SEF Fishery Assessment Report 1999                                                                             7
                   25000
                                                                                                                                                              1986

                                                                                                                                                              1991
                   20000
                                                                                                                                                              1996

                   15000
    Effort (hrs)




                   10000



                    5000


                                0
                                    0           100         200         300         400         500         600         700     800     900     100     110      >12
                                                                                                                                                0       0        00

                                                                                                 Depth (m)

                                                             Trawlers only. Hours not always recorded for Danish seine

Figure 5 Trawl fishing effort by depth, 1986, 1991 and 1996 (Data source: SEF1 logbook data)



The impact of orange roughy during 1986 to 1996 is reflected in the changes in effort distribution by depth
and, to a greater extent, the changes in catch with depth. Nevertheless, even when orange roughy catches
were at their peak, most effort in the fishery remained in waters of less than 500 m depth with a constant
peak in shelf waters of between 100 and 150 m. Figure 6 clearly shows the decline in orange roughy catches
over this period. The 1996 effort plot (Figure 5) also shows the shift to blue grenadier and ling fishing, with
the secondary effort peak in depths from 400 to 550 m stemming from increased targeting of these species.




                                7000                                                                                                                             1986
                                                                                                                                                                 1991
                                6000
                                                                                                                                                                 1996
                                5000

                                4000
                    Catch (t)




                                3000

                                2000

                                1000

                                        0
                                            0         100         200         300         400         500         600         700     800     900     100      110      120
                                                                                                                                                      0        0        0+


                                            Note: Trawlers only                                             Depth (m)


Figure 6 Total retained catch by depth recorded in trawl sector logbooks, 1986, 1991 and 1996 (Data
source: SEF1 Logbook data)




8                                                                                                                             SEF Fishery Assessment Report 1999
Table 1 Annual landings of quota species by major ports from 1994 to 1998 (Data source : AFMA Quota Monitoring System)
                                                                                                                      Annual landed catch (tonnes) of quota species




                                                                                                                                                                                                                      Warehou -



                                                                                                                                                                                                                                  Warehou -
                                                                                                                           John dory




                                                                                                                                                                                    Royal red
                                                                                    Gemfish -



                                                                                                Gemfish -
                                      combined




                                                             grenadier




                                                                                                            morwong
                                      All quota



                                                  Blue-eye




                                                                         whitting




                                                                                                                                                                                                           flathead
                                                                                                            Jackass
                                                  trevalla




                                                                                                 western




                                                                                                                                                                                                trevally
                                                                                                                                                                          Redfish
                                                                                                                                                                Orange
                                                                                     eastern




                                                                                                                                                                                                                                   spotted
                                                                                                                                                                roughy
                                                                                                                                               Mirror
                                                                          School




                                                                                                                                                                                     prawn
                                                                                                                                                        Ocean




                                                                                                                                                                                                 Silver
                                                                                                                                                        perch




                                                                                                                                                                                                             Tiger
                               Year




                                                                                                                                        Ling



                                                                                                                                                dory
                                                               Blue
                      Port




                                                                                                                                                                                                                        blue
     Wollongong              1995        398            0           0          0           6           0         0         15           18        22      14        1    160           123            0        38            0           0
                             1996        427            0           0          0       112             0         0         16           12        39       9        0    102             90           1        46            0           0
                             1997        364            0           4          2         41            0         0             3        21        41      21        0    116             85           0        29            0           0
                             1998        320            0           3          2         46            0         0             4        18        26      19        0    116             58           0        27            0           0
     Ulladulla               1995     1,180             1         10           0           9           0       15          44          103        43      40        0    678             26         78       115           15            2
                             1996     1,215             1           7          1         51            0       17          50          110        63      50        0    575             52         66       153           16            4
                             1997     1,258             1           9        12        127             0       10          19          124        68      44        0    700               8        66         70            1           1
                             1998     1,402             1         41           0         65            0       12          23          125        74      63       16    822               7        58         90            1           3
     Bermagui                1995        829            1           6          0         12            0       27          28          135        26      36        0    167               1        82       137         100           68
                             1996        880            2         11           1         16            0       30          21          113        32      46        0    244               0        84       117         117           46
                             1997        748            1         13           0         37            0       17          14          127        39      43        0    196               0      147          95          16            5
                             1998        721            1         18           0         17            0       13          20          135        42      36        0    251               5        68         83          16          16
     Eden                    1995     3,922             9       117          11          40            0      391          72          461        62      82       43    257               0      196        624         341      1,216
                             1996     3,818           11        134            5         40            0      423          57          470        54     113      101    358               0      138        543         380         991
                             1997     4,187           12        231            0       138             0      651          34          547        95     133       12    333               0        57       669         374         901
                             1998     3,874           13        397            2         55            0      447          56          535        62      95       23    391               0        30       668         451         650
     Lakes Entrance          1995     2,646             4         88       901             9           0      193          15          100        22      17      130        5             0          6      960           53        141
                             1996     2,488             4         78       597           13            0      242          15          116        22      21      129     15               0          9      997           53        178
                             1997     2,682             4         58       355           21            0      265          20          110        22      16       54     27               0          6    1,527           63        133
                             1998     2,535             4       132        287           10            0      235          14          105        14      17        7     10               1          4    1,522           52        121
     Portland                1995     3,076           13        931            2           1         52        12              0       298        23      32      919        0             0          0          3       310         480
                             1996     3,377           21        717            0           0       119         30              0       268        94      32    1,356        0             0          0          4       169         568
                             1997     2,770           45        630            0           0       131         36              0       392       109      56      410        0             0          0          9       293         658
                             1998     3,129           26     1,142             0           0       119         15              0       337        85      37      349        0             0          0          2       342         675
     Hobart                  1995     4,258           23        261            0         10            0      184              0        36        28       8    3,469        1             0          0        48          69        122
                             1996     3,343           25        272            0         14            4      132              0        65        34      10    2,396        0             0          1        38          73        278
                             1997     6,864             8    2,074             0         24            0      117              0        64        30       9    4,193        0             0          1        46          25        272
                             1998     3,544             9         91           1         29            0      111              0        25        11       4    3,034        0             0          0        62          11        157
     Other                   1995     4,061           17     1,358         387           11          72        40          35          263        55      88      725     98           214        106        119           72        403
                             1996     5,421           18     1,821         393           13          85        23          28          301        81      79    1,174    266           260        118        217           46        498
                             1997     5,330           43     1,514         383           43          95        40          13          370       142     101    1,007    223           202          94       232           22        804
SEF Fishery Assessment Report 1999
                   1998  7,382   42                          3,909         346           27          66        49          11          416
                                                                                                                                               9 115      95      777    183           214          74       210           60        788
                   60,000
                                                                              Orange Roughy

                                                                              Other quota species
  Catch (tonnes)



                   50,000

                   40,000

                   30,000

                   20,000

                   10,000

                       0
                            19   19   19   19   19   19   19   19   19   19     19   19   19
                            86   87   88   89   90   91   92   93   94   95     96   97   97
                                                                                     a    b
                                                      Year

Figure 7. Annual retained catch of orange roughy and other quota species recorded in trawl sector logbooks, 1986 to
1997 (Data source:1986 to 1991 - SEF1 logbook data; 1992 to 1997 AFMA Quota Monitoring System (SEF2) plus
State declared catches. 1997a is without Cascade and South Tasman Rise catches and 1997 b is with them.



Annual recorded trawl landings of quota species have ranged from 12126 t to 59069 t since 1984, with the
peak being at the height of the orange roughy ―boom‖ in 1990. This species formed the bulk of landings
from 1989 to 1992. Total catches of quota species other than orange roughy range from about 12500 t in
1992 to over 20000 t in 1986 (Figure 7). The 1992 value is thought to be significantly lower than the true
value because of under reporting due to surveillance problems in the first year of ITQ management.
Comparison with the proportion of non-quota species in recorded landings (excluding orange roughy)
support this assumption. This proportion was highest in 1992 (Figure 8), indicating that quota species were
under reported. In 1997, SEF2 trawl landings (including those from State waters) totalled 22560 t, with the
catch of quota species other than orange roughy being 18513 t, 6.3 per cent lower than 1996. The 1997
orange roughy landings total of 4047 t was 21.5 per cent less than 1996 (5155 t), but a further 1532 t were
landed from the South Tasman Rise outside the AFZ. Excluding orange roughy tonnage, SEF non-quota
species landings have comprised just over 20 per cent of the total recorded landed weight for the period
1986 to 1996 and constituted 22.4 per cent of the 1997 total. Figure 8 indicates that there has not been a
significant increase in landings of non-quota species since ITQ management was introduced.
It should be stressed that the above figures are for landed (SEF1 and SEF2) catches only. An onboard
scientific monitoring program has shown that a significant proportion of the catch of some quota species is
discarded at sea. Therefore the actual catch is considerably greater for some species.
Over the period 1984 to 1996, dramatic changes in the species composition of the catch have occurred.
These were initially due to the collapse of the eastern gemfish fishery and the discovery of orange roughy
resources. In 1984, 21 per cent of the catch was eastern gemfish, with tiger flathead and redfish being the
next two important species (Figure 9).
By 1990, the orange roughy ―boom‖ was well under way, with 74 per cent of the recorded catch being this
species and landings of the more traditional species being reduced to only a few percent of the total tonnage
(Figure 9). Following the decline of the orange roughy fishery, the proportion of this species in the catch
(excluding catches from outside the quota zones) dropped to 25 per cent in 1996 and was much lower (13.4
per cent) in 1997. However, it should be noted that 1178 t and 1532 t were landed from the Cascade
Plateau and South Tasman Rise, respectively, in 1997. Increased targeting on ling and spotted warehou has
improved their representation in the catch (Figure 9).




10                                                                            SEF Fishery Assessment Report 1999
                                       Non-quota species
                                       Quota species - excluding orange roughy
                         100%
  Precentage of annual


                         80%
       landings



                         60%

                         40%

                         20%

                          0%
                                1986

                                        1987

                                               1988

                                                      1989

                                                             1990

                                                                    1991

                                                                           1992

                                                                                  1993

                                                                                         1994

                                                                                                1995

                                                                                                       1996

                                                                                                              1997
                                                                      Year

Figure 8. Proportion of annual retained catch of quota species ( excluding orange
roughy) and non-quota species recorded in trawl sector logbooks, 1986 to 1997 (Data
source: SEF1 logbook data)

About 140 vessels were operating in the trawl sector in 1991. The number of active vessels has declined by
about 23 per cent since the introduction of quotas. In 1997 there were 108 active vessels, although a further
42 fishing permits were held by inactive (i.e. did not register SEF2 landings) fishers at the start of the year.
In 1997 a Commonwealth funded adjustment scheme removed 27 of the 150 permits available for the
fishery (a further 5 have subsequently been removed, bringing the total number of permits to 118). Total
effort recorded in the SEF logbook fluctuated between 1986 and 1993, both in terms of number of shots
and number of hours trawled (Figure 10). The low figure in 1992 was again almost certainly a result of
under-reporting. More recently, there has been a significant increase and the 1997 trawl effort figures
(101243 hrs bottom time) are the highest on record (Figure 10). On average, about 35000 shots have been
made each year, representing 75000 to 80000 hours bottom time.
Effective (i.e. actual) effort has risen even more than suggested by the number of shots and number of
hours, because of advances in fishing technology and increases in vessel horsepower. This increase in the
efficiency of vessels is difficult to quantify but must be taken into account when considering trends in catch
and effort data. The expansion of trawl grounds has also occurred. With the advent of increasingly
sophisticated acoustic and navigation aids, such as global positioning systems and plotters, some areas
previously thought to be inaccessible because of the incidence of rough, hard bottom and the likelihood of
―hook-ups‖ and gear loss occurring are now able to be trawled.
Few management measures were in place for the SEF before 1985. Although there was a limit on the
number of trawlers greater than 32 m in length permitted to enter the fishery there were no regulations
controlling the number of vessels less than this size. The only restrictions were minimum cod-end mesh
sizes for trawlers and Danish seiners, and minimum legal sizes for several species. In 1985, management
arrangements based on limited entry into the fishery were introduced. The fishery was divided into three
Sectors with different entry criteria for each. In an attempt to limit fleet capacity, a boat replacement policy
(based on units of capacity) was formally introduced in 1986 (and subsequently removed with the onset of
ITQ management) to prevent the expansion of effort through upgrading or replacing boats. Other input
controls have included a freeze on transfers of licences between Danish seining and trawling.




SEF Fishery Assessment Report 1999                                                                                   11
Figure 9 Species composition of retained catches recorded by the trawl sector, 1984, 1990, 1996 and 1997. (Data
sources: 1984, Verified catch data; 1990, AFZIS, SEF1 logbook data; 1996/97 AFMA Quota Monitoring System)




                                                                                          hours

                120,000                                                                   shots
                100,000
                 80,000
       Effort




                 60,000

                 40,000
                 20,000

                     0
                          1986

                                 1987

                                        1988

                                               1989

                                                      1990

                                                             1991

                                                                     1992

                                                                            1993

                                                                                   1994

                                                                                           1995

                                                                                                  1996

                                                                                                         1997




                                                               Year

Figure 10 Total trawl and Danish seine effort in the SEF as recorded in logbooks, 1986-1997 (Data source: SEF1
logbook data)




12                                                                  SEF Fishery Assessment Report 1999
Despite these management measures, fishing capacity and effort continued to increase, particularly with the
development of the orange roughy fishery. Excepting this deepwater fishery, the SEF was seen to be in a
worsening economic situation, with management based entirely on input controls that theoretically resulted
in the progressive reduction of economic efficiency of operators. The decline of the eastern gemfish and
redfish stocks exacerbated this situation. TACs were introduced for gemfish in 1988 and orange roughy in
1990. ITQ management was introduced for all 16 quota species or species-groups on 1 January 1992.
The total agreed SEF trawl TAC for 1997 was 32 965 t (Table 2), of which blue grenadier accounted for
10000 t and orange roughy 5500 t (including 1000 t for the Cascade Plateau). The ―carry-over‖ rule, which
allows up to 20 per cent of uncaught tonnage per quota species to be carried over to the following year,
continues to have a marked effect in this fishery. Thus, a further 6220 t (18.9 per cent) was allocated across
all species later in the year after adjustment for this rule. The gap between the ―agreed‖ and ―actual‖ TAC
totals appears to be narrowing as the difference between the respective totals for 1997 was less than that in
1996 (21.6 per cent). This gap fell further in 1998, when the actual TAC total of 39 120 t was only 13.9
per cent (4789 t) higher than the agreed total of 34 331 t. However, for species such as blue grenadier the
actual TAC remains excessively high, with it being 24 per cent greater than the agreed TAC in 1998,
despite 4534 t of quota being landed in 1997.
In 1997, catches of 3 species (ling, orange roughy-eastern management zone and Cascade Plateau, and
spotted warehou) slightly exceeded their respective actual TACs. Whereas blue-eye trevalla (76 per cent),
blue warehou (89 per cent), flathead (61 per cent), jackass morwong (62 per cent), ocean perch (65 per
cent), redfish (77 per cent), and western gemfish (65 per cent) landings were all greater than 60 per cent of
their actual TACs, catches for the remaining species were well below their TAC levels (Figure 11).
However, if discarding is taken into account, the total (i.e. as against landed) catch of a few species with
high discard rates (e.g. ocean perch) probably exceeded the TAC.
The 1998 total actual TAC is 39 120 t. This is higher than the actual TAC of 38 186 t in 1997, principally
because of a 1000 t increase in the spotted warehou TAC. The recent decline in the total orange roughy
TAC has been more than matched by increases in TACs for other species, with blue grenadier, ling, redfish
and spotted warehou having the largest increases over this five year period.
NSW Fisheries has imposed trip limits on certain quota species taken in waters under its jurisdiction (Table
3). These limits reduce the opportunity for claiming that catches taken in Commonwealth waters were
actually taken in State waters and therefore do not count against quota.




                                                       Catch reported from State waters
            120
                                                       Catch reported from Commonwealth waters
                                                       TAC

            100



            80
 % of TAC




            60



            40




            20



             0
                                                                                                                                                                                                                                                                                                                           Silver trevally
                  Blue eye trevalla




                                                                                                                                                    Ling
                                      Blue grenadier




                                                                                                                                                                                                                                                                                        Royal red prawn
                                                                                                                                                           Mirror dory
                                                        Blue warehou




                                                                                                                                                                                                                                                                                                          School whiting
                                                                       Eastern gemfish




                                                                                                                                                                         Ocean Perch




                                                                                                                                                                                                                                                                              Redfish
                                                                                                           Flathead


                                                                                                                      Jackass morwong




                                                                                                                                                                                                                                                       Orange roughy remote
                                                                                                                                        John dory
                                                                                         Western gemfish




                                                                                                                                                                                                                                                                                                                                             Spotted warehou
                                                                                                                                                                                                                                  Orange roughy west
                                                                                                                                                                                       Orange roughy east


                                                                                                                                                                                                            Orange roughy south




                                                                                                                                                                Species

Figure 11 Proportion of allocated TAC caught during 1997 by the SEF trawl sector (Data source: AFMA
Quota Monitoring System)


SEF Fishery Assessment Report 1999                                                                                                                                                                                                                                                                                                                             13
Table 2 Total allowable catches for SEF quota species 1992 to 1997 (AFMA)

                              Agreed       Actual      Agreed        Actual      Agreed    Actual   Agreed   Actual   Agreed   Actual   Agreed   Actual   Agreed   Actual
                               1992         1992        1993          1993        1994      1994     1995     1995     1996     1996     1997     1997     1998     1998
Blue eye trevalla                125        125            125          147         125       135      125      139      125      147      125      149      100      116
Blue grenadier                 5,000      5,000          5,000        5,495      10,000    12,351   10,000   12,281   10,000   12,634   10,000   12,496   10,000   12,409
Blue warehou                    2000       2090          1,000        1,010       1,000     1,070    1,000    1,087    1,000    1,174      700      883      820      880
                          (combined) (combined)
Flathead                       3,000      3,027          3,000       3,129        3,500     3,823    3,500    4,195    3,500    4,300    3,500    4,134    3,500    4,009
Gemfish eastern                  200        208              0           0            0         0        0        0        0        0    1,000    1,000      300      300
Gemfish western                  300        325            300         334          300       330      300      355      300      369      300      347      300      334
Jackass morwong                1,500      1,551          1,500       1,593        1,500     1,626    1,500    1,764    1,500    1,787    1,500    1,800    1,500    1,779
John dory                        240        243            240         251          240       263      240      275      240      292      240      294      240      296
Ling                             700        780            800         809        1,000       995    1,500    1,524    1,500    1,604    1,600    1,734    1,921    1,912
Mirror dory                      600        700            800         803          800       879      800      953      800      978      800      978      800      962
Ocean Perch                      200        300            300         302          500       509      500      574      500      601      500      603      500      587
Orange roughy east             7,500      8,128          1,500       2,039        1,500     1,571    2,000    1,920    2,000    1,940    2,000    1,972    2,000    1,909
Orange roughy south            8,500      8,500         10,000      10,582        5,000     7,735    4,000   5, 424    3,000    4,208    1,000    1,813    1,000    1,000
Orange roughy west             1,500      1,626          1,500       1,677        1,500     2,221    1,500    1,912    1,500    1,804    1,500    1,717    1,500    1,933
Orange roughy cascade              -          -              -           -            -         -        -        -        -        -    1,000    1,000    1,600    1,600
Redfish                          600        617            600         601        1,000     1,030    1,700    1,842    1,700    1,951    1,750    1,993    1,750    2,042
Royal red prawn                  400        500            500         553          500       537      500      590      500      617      500      624      500      625
School whiting                 2,000      2,000          2,000       2,057        2,000     2,203    2,000    2,423    2,000    2,416    2,000    2,359    2,000    2,423
Silver trevally                  400        500            500         500          500       548      500      590      500      612      500      614      500      621
Spotted warehou                 2000       2090          2,000       2,020        2,500     2,604    2,500    2,823    2,500    2,881    2,500    2,675    3,500    3,383
                          (combined) (combined)
Total                         34,890       36,345       31,665      33,902       33,465    40,430   34,165   35,247   33,165   40,315   32,965   39,185   34,331   39,120



Actual = Agreed TAC plus carry overs and unders from previous year.
    In 1992 the two warehou species were combined.
    The TAC for the Cascade Plateau is a ―competitive‖ TAC and is not allocated as ITQs




14                                                                        SEF Fishery Assessment Report 1999
Table 3    NSW trip limits for 1997 (NSW Fisheries)

   Quota Species                       Area                         Period             Gear          Daily Trip
                                                                                                       Limit
Gemfish                all waters                            1/5 to 30/9              all gears           100kg
                       all waters                            all other months         all gears           200kg
Redfish                all water south of BJ                 all year                fish trawl           100kg
                       all water north of BJ                 1/7 to 31/10            fish trawl          1000kg
                       all water north of BJ                 all other months        fish trawl           250kg
Orange roughy          all waters                            all year                 all gears              0kg
Pink ling              within 3 nm of coastal baseline       all year                 all gears              0kg
Blue eye trevalla
Blue grenadier
Royal red prawn
Blue warehou           all waters                            all year                all gears              100kg
Spotted warehou        all waters                            all year                all gears               50kg
Jackass morwong
Ocean Perch
Tiger flathead         all water south of BJ                 all year                all gears              200kg


The SEF trawl fishery continues to be an important component of the Australian fishing industry, taking the
largest tonnage and supplying most of the fresh fish for Sydney and Melbourne. The 1997 value of the
fishery was approximately $60 million, $16.5 million of this being for orange roughy (Table 4). The
orange roughy total includes landings from the Cascade Plateau and South Tasman Rise. Average monthly
prices were calculated from the Melbourne and Sydney fish market‘s prices. For each species, annual
values were calculated by weighting monthly prices according to monthly catches. The market prices were
multiplied by a factor of 0.79 to estimate prices received by fishers (i.e. marketing costs of 21 per cent
have been deducted from the market price). Thus, the values represent the returns to the catching sector.
The relative values of the major species are shown in Figure 12 which again illustrates the decline in the
SEF orange roughy fishery.
Information on the discarded portion of the SEF catch was gathered from two complementary on-board
observer programs for the period 1993-1996 and is being continued with an Integrated Scientific
Monitoring Program (ISMP). The data show that the proportion of catch discarded has varied considerably
between different parts of the SEF. Discarding of quota species off NSW (Eastern Zone A and Eastern
Zone B) is of particular concern, with about 30 per cent by weight of the total catch of quota species
between 1993 and 1996 being discarded. This amounted to about 15 per cent by weight of the overall
catch. From 1993-96, annual discard rates were greatest for redfish (47-56 per cent by weight), blue
warehou (6-23 per cent), gemfish (8-82 per cent), mirror dory (15-56 per cent), tiger flathead (12-15 per
cent) and ocean perch (offshore species 25-56 per cent, inshore species 83-86 per cent). Discard rates were

                    1992                                                1997       Orange roughy
                              Other       Orange roughy
               Jackass        10%                                                      25%
                                              67%
             morwong 2%
                                                                Other
               Blue warehou
                                                                22%
                    2%
           Spotted                                                                                 Blue grenadier
          warehou 1%                                                                                    20%

                 Ling 3%                                    Jackass
                Flathead 5%                               morwong 2%

                                                          Blue warehou                        Flathead 5%
                     Blue grenadier
                          10%                                  2%      Spotted
                                                                                   Ling 3%
                                                                      warehou 1%

Figure 12. Comparative value of species in 1992 and 1997. 1997a shows percentages without orange roughy
landings from the Cascade Plateau and South Tasman Rise and 1997b shows percentages with them. (Data source:
ABARE)



SEF Fishery Assessment Report 1999                                                                                  15
Table 4 Estimated gross value of recorded catches by the trawl sector (ABARE)
     Quota Species                     1996                                  1997                      1998
                          Catcha       Value                 Catcha          Value           Catcha    Value
                            t          $000        $/kg        t             $000     $/kg     t       $000     $/kg
Quota Species
Blue eye trevalla            81          427       5.27        113             496    4.40        96      594   6.19
Blue grenadier             3,040        7,600      2.50       4,538           9,892   2.18      5734     8830   1.54
Blue warehou                854         1,657      1.94        794            1,493   1.88       932     1640   1.76
Flathead                   2,114        3,869      1.83       2,677           4,390   1.64      2664     5115   1.92
Gemfish                     324         1,134      3.50        624            1,653   2.65       399     1213   3.04
Jackass morwong             896         1,658      1.85       1,136           1,715   1.51       883     1422   1.61
John dory                   186         1,053      5.66        103             626    6.07       127      690   5.43
Ling                       1,449        4,724      3.26       1,756           5,075   2.89     1 692     5634   3.33
Mirror dory                 403          697       1.73        547             951    1.74       426      826   1.94
Ocean perch                 356          972       2.73        423            1,126   2.66       363      937   2.58
Orange roughy b            4,983       12,458      2.50       5,715          16,516   2.89      4174   12 689   3.04
Redfish                    1,548        1,594      1.03       1,597           1,773   1.11      1770    1 894   1.07
Royal red prawn             404         1,159      2.87        296             815    2.75       282    1 041   3.69
School whiting              996         1,295      1.30        754            1,184   1.57       638    1 072   1.68
Silver trevally             417          592       1.42        372             558    1.50       233      366   1.57
Spotted warehou            2,563        2,922      1.14       2,785           3,899   1.40      2411    2 797   1.16
 Quota spp. Total         20,614       43,810                 24,229         52,160           22 824   46 759
Non-quota Species
King Dory                   154         501        3.25        147            421     2.86     1 226    4 365   3.56
Smooth oreo                 327         278        0.85        962           1,606    1.67     1 297    2 114   1.63
Spiky oreo                  428         561        1.31       1,073          1,503    1.40       711    1 102   1.55
Other                      3,223       4,835       1.50       3,160          4,413    1.40     1 945    2 050   1.05
Non-quota spp              4,132       6,174                  5,342          7,943             5 179    9 631
total
Total                     24,746       49,983                 29,570         60,104           28 003   56 390
a
  Catches recorded by Commonwealth boats in Commonwealth and State waters.
b
  Includes catches taken outside quota zones.
Data sources: Average monthly prices from the Melbourne and Sydney fish markets. For orange roughy, processor
prices were also used from July 1992. Catch information derived from SEF1 and SEF2 forms.

much lower off west Tasmania, where 80 per cent of the catch consisted of retained quota species. The
Western Zone and the eastern Victorian Danish seiners had low discard rates for quota species, but still
discarded close to half their total catch (e.g. Figure 13).
In 1997, there was a significant reduction in the discarding of quota species to 9 per cent of the total catch
weight in Eastern Sector A and 6 per cent in Eastern Sector B (Figure 14). Much of this reduction was due
to redfish discards only being 6 per cent by weight compared with 24 per cent in 1996. Conversely,
discards of blue grenadier off NSW were again high, but catches of this species were low in comparison to
redfish. 1997 discard rates for other NSW species were similar to those in 1993-96. In the Western Zone,
the total discards of quota species rose sharply from 10 per cent by weight of the overall catch in 1996 to
32 per cent in 1997, largely because of a marked increase in juvenile blue grenadier catches and a
consequent 15 per cent by weight discarding rate for this species.




16                                                                     SEF Fishery Assessment Report 1999
                      E astern Z one A
                            1996                                             Q uo ta
                                                                              12%

                                                                                         No n-q uo ta
                                           Q uo ta                                       c o mmerc ial
                                            40%                                             16%
                         Retain ed                                                                  Discard ed
                           57%                                                                         43%
                                                                                       No n-c o mmerc ial
                                                                                             15%
                                                            No n-q uo ta
                                                            c o mmerc ial
                                                               17%



                      E astern Z one B
                                                                       Q uo ta
                            1996                                           7%


                                                                                          No n-q uo ta
                                          Q uo ta
                                                                                         c o mmerc ial
                                           39%
                                                                                             27%
                        Retain ed                                                                        Discard ed
                          53%                                                                               47%


                                                                                 No n-c o mmerc ial
                                                     No n-q uo ta                         13%
                                                     c o mmerc ial
                                                        14%




                       E astern Tas.
                           1996                                       Q uo ta
                                                                                    No n-q uo ta
                                                                        7%
                                                                                  c o mmerc ial
                                                                                         12%
                                                                                                            Discard ed
                                                                                                               30%
                        Retain ed                                                        No n-c o mmerc ial

                          70%                                                                   11%


                                          Q uo ta                                        No n-q uo ta

                                          66%                                            c o mmerc ial
                                                                                               4%




                      W estern Z one
                           1996                                               Q uo ta
                                                                                10%


                                             Q uo ta                                                     Discard ed
                                              35%
                                                                                                            50%
                        Retain ed
                                                                                            No n-q uo ta
                          50%                                                               c o mmerc ial
                                                                                                35%


                                            No n-q uo ta
                                            c o mmerc ial                   No n-c o mmerc ial
                                                15%                                5%




Figure 13 Composition of the total catch, retained and discarded by weight during 1996 for four areas of the trawl
sector (Source: ISMP)




SEF Fishery Assessment Report 1999                                                                                       17
                      Eastern Zone A                                 Q uota
                                                                       9%
                           1997

                                       Q uota
                                                                                          N on-quota
                                        38%
                                                                                         com m ercial
                                                                                             26%
                         Retain ed                                                                        Discard ed
                           52%                                                                               48%



                                                                              N on-com m ercial
                                                N on-quota
                                                                                    13%
                                                com m ercial
                                                   14%



                                                                   Q uota
                      Eastern Zone B
                                                                    6%
                           1997

                                                                                         N on-quota

                                       Q uota                                           com m ercial

                                        40%                                                 27%

                         Retain ed                                                                        Discard ed
                           50%                                                                               50%



                                                                              N on-com m ercial
                                                   N on-quota
                                                                                     17%
                                                  com m ercial
                                                      10%



                       E astern Tas.
                                                                              Q uo ta
                           1997                                                20%




                                      Q uo ta
                         Retain ed                                                        No n-q uo ta    Discard ed
                                       50%
                           61%                                                           c o mmerc ial       39%
                                                                                             15%


                                                                                  No n-c o mmerc ial
                                                                                           4%
                                                                  No n-q uo ta
                                                                 c o mmerc ial
                                                                     11%



                      W estern Zone
                           1997
                                                                                          Q uota
                                                                                          32%
                                      Q uota
                                       34%
                         Retain ed                                                                       Discard ed
                           49%                                                                              51%

                                                                                        N on-quota
                                                                                        com m ercial
                                             N on-quota                                    17%
                                           com m ercial
                                                                 N on-com m ercial
                                                15%
                                                                         2%




Figure 14 Composition of the total catch, retained and discarded by weight during 1997 for four areas of the trawl
sector (Source:ISMP)




18                                                                                 SEF Fishery Assessment Report 1999
Non-trawl sector
On 1 January 1998 ITQs were introduced to the South East Non-trawl Fishery for its three key species, blue
eye trevalla, ling and blue warehou. A suite of gear and area based input controls are also placed as
constraints on South East Non-Trawl Fishing Permits, but these are under review following the introduction
of ITQ management. There are now 155 Fishing Permits granted for the South East Non-Trawl Fishery.
The South East Fishery Non-trawl Consultative Committee (SEFNTCC) was established in 1994 to provide
a forum for stakeholders to develop long term management arrangements for the sector. Criteria for future
access to the non-trawl sector were developed during 1994/95. Commonwealth fishing permits were
assessed against these criteria from 1 October 1996, with State licences being subjected to the access
criteria from the implementation of revised OCS agreements (except off NSW). About 200 operators met
the access criteria. The sector was initially managed through limited entry and gear and area restrictions.
In November 1995, interim additional gear restrictions were introduced on line methods in waters south of
40o S in response to concerns of some members of Tasmanian industry regarding increasing catches of blue
eye trevalla in that area. As a further interim measure, a competitive TAC of 250t was introduced for blue
warehou in 1997.
SEF non-trawl fishers are generally diversified, often operating in State rock lobster fisheries and the East
Coast Tuna and Billfish Fishery. Fishers in the SEF non-trawl sector using demersal gillnet methods are
also involved in the Southern Shark Fishery. These fishers are subject to the restrictions on the use of
gillnets currently in place in the Southern Shark Fishery. Many of these gillnet operators have traditionally
targeted scalefish, particularly blue and spotted warehou.
Prior to 1997, no Commonwealth logbook was in place for the SEF non-trawl sector, although permit
holders had been required to complete relevant state logbooks. A specific Commonwealth non-trawl
logbook was introduced on 1 January 1997 and catch landing (monitoring) record logbooks were
introduced to the entire fishery on 1 January 1998. Hence, the logbook data time-series is too short to
provide the equivalent of the comparative tables and figures used above in describing the trawl sector.
The agreed TACs for the three key species in the non-trawl sector for 1998 were 530t for blue eye trevalla,
1180t for blue warehou and 279t for ling.
In July 1998, the membership on SEFNTCC expired and the South East Non Trawl Management Advisory
Committee (SENTMAC) was established by the AFMA Board to provide ongoing management advice.




SEF Fishery Assessment Report 1999                                                                         19
2.     MAJOR STAKEHOLDERS

EXTRACTIVE
commercial fishing:                   trawl, Danish seine, hook, gill-net, trap
recreational fishing:                 anglers (substantial for some species), gill-net (Tas)
traditional fishing:                  unknown
aquaculture (broodstock/juveniles):   zero for quota species
aquarium:                             very limited, potential in State waters

NON EXTRACTIVE
tourism:                              varied, substantial
diving:                               expanding
conservation:                         protected areas
aboriginal heritage:                  native title claims - currently for coastal lands, but
                                      could extend to fishing rights

OTHER
post harvest interests:               processors, cooperatives, wholesalers and retailers, consumers
infrastructural interests:            recreational and commercial marina development
other industries:                     various industries associated with fishing and
                                      tourism including charter boat operators.

The stakeholders listed above relate directly to the main resource of the SEF, namely the fish. The scope
can be expanded to cover stakeholders with interests in the marine environment overall and the associated
terrestrial environment. A more comprehensive assessment of stakeholders is being carried out for the
―South Eastern Large Marine Ecosystem,‖ a region that overlaps the SEF. This work is part of the Fishery
Ecosystem Management initiative of the Standing Committee on Fisheries, Forestry and Aquaculture.
Currently, the Commonwealth‘s Environment Australia is coordinating a plan to develop a national
representative system of marine and estuarine protected areas under the Ocean Rescue 2000 program. This
and other initiatives under the ―Oceans Policy‖ umbrella are expected to become increasingly important for
the SEF.




20                                                             SEF Fishery Assessment Report 1999
3.     AUSTRALIAN FISHERIES MANAGEMENT AUTHORITY (AFMA)
       MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE
       INDICATORS

OVERALL OBJECTIVES
 To ensure that SEF resources are utilised in a manner consistent with the principles of ecologically
  sustainable development and to maximise economic efficiency in the utilisation of fish resources.
 To promote the rebuilding of depleted fish stocks and to promote the identification and development of
  additional or under-utilised fish resources of the fishery.
 To implement effective and efficient fisheries management on behalf of the Commonwealth.

IMMEDIATE OBJECTIVES
The most heavily utilised species comprise the bulk of the fishery and are managed under the trawl and
non-trawl sector‘s individual transferable quota (ITQ) system. Depending upon the status and nature of
each species, immediate objectives for the management of quota species are:

 to ensure the spawning or recruited biomass of specified species does not significantly decline below
  recent levels; or
 to maintain the long-term productivity of stocks of specified species; or
 to rebuild the stocks of specified species to levels at which targeted commercial fishing may
  recommence; or
 to develop or increase the utilisation of specified species; or
 to develop mechanisms to forecast future catches of specified species.

STRATEGIES
The use of appropriate management measures to ensure that fish resources in the SEF are utilised in a
manner consistent with the principles of ecologically sustainable development (ESD) through the setting of
TACs and ITQs for the Commonwealth managed portions of the fishery:

 where estimates of biomass are available and subject to specific biological advice to adopt an
  alternative figure, to ensure that the spawning biomass of particular species do not decline below 30 per
  cent of their level at the onset of significant commercial fishing;
 where estimates of biomass are not yet available, but may be at some point in the future, to ensure that
  catch per unit effort (CPUE) is maintained above its lowest annual average level from 1986 to 1994.

Obtain estimates of total catch, catch rates and monitor shifts in effort and changes in fishing practice.
Determine length distributions in commercial catches and gather age distribution data. Refine estimates of
spawning biomass at the onset of significant commercial fishing and the current spawning biomass of each
specified species. Where appropriate, develop recruitment indices.
Monitor economic data regarding market demand, GVP and market prices for each species and analyse
data to provide an indication of the economic health of the fishery. Examine necessary management
alternatives to encourage more efficient utilisation of resources.
Give each quota species in the SEF a priority ranking in relation to each other and define research needs.

PERFORMANCE INDICATORS
The status of each quota species resource relative to their objectives:

 estimation of current spawning biomass, where possible, compared to spawning biomass at the onset of
  significant commercial fishing;
 the current annual CPUE for specified species is above its lowest annual average from 1986 to 1994.
· The actual catch relative to the TAC.
The economic and financial performance of the fishery.
The effectiveness of research programs contributing to the objectives set for each species, including:



SEF Fishery Assessment Report 1999                                                                           21
 reduction in uncertainty regarding biomass estimates;
 total catch figures for each species;
 catch and effort data extracted and analysed for specified species;
 length and size/age distribution have been collected and analysed for specified species;
 for specified species, risk analyses are completed and are used to evaluate alternative management
  strategies;
 where appropriate, recruitment indices have been developed.

DISCUSSION
The development of management objectives, strategies and performance indicators for inclusion in the
SEFAG Fishery Assessment Report has been an evolving process since the first report in 1993, with
amendments and refinements made each year. One intention of the objectives, strategies and performance
indicators is that they link directly back to the upcoming SEF Management Plan and ultimately back to the
objectives stated in the AFMA Corporate Plan, 1997-2002 and thus to the Fisheries Management Act 1991.
Objectives, strategies and performance indicators should provide clear identification of the reasons for
managing a particular species; the thresholds or boundaries for the management of each species, which if
reached will require specific, pre-agreed management action; and finally, the yardstick against which
management arrangements are measured.
Using the principles of ESD as a guide, general objectives for managing fisheries resources are to balance
the reducing, maintaining or rebuilding of a spawning fish stock, with maximising the net profit from the
fishery (i.e. maximising the difference between landed value and harvesting costs).
In order to focus on what is happening to fish stocks which are left in the water, the question managers are
now asking is “How many fish should be left in the water to meet our ESD obligations?” This relates
then to the concept of ―limit reference points‖, which would set a minimum biological limit (eg. of
spawning biomass) and once reached, a pre-agreed plan of action would be implemented. A ―target
reference point‖ can also be set in place and refers to the ―optimal‖ state of a stock based primarily on
economic objectives (with the biology of the resource as an underlying basis).
The data available for a particular species will link to the appropriate limit or target reference points based
on biomass, yield or fishing mortality. At this stage, there are a number of species for which biomass
estimates will not be available for some time. Indeed, a more appropriate reference point may be a target
fishing mortality rate, although this could be just as difficult to estimate as biomass. In the short-term,
strategies for these species will relate to maintaining catch per unit effort within or above historical levels.
AFMA is yet to decide on the most appropriate reference points for some species as the process for
determining them is still evolving. It is not intended that available data dictate these reference points, but
rather, once reference points are agreed to (derived from biological characteristics and the value and
priority of the species) they will determine the research needs. AFMA's Corporate Plan, 1997-2002 sets out
corporate strategies relating to the setting of biological reference points for Commonwealth fisheries.
Within the next five years, appropriate reference points will be determined for all major species.
A key advantage of specifying ESD or biological objectives (limit reference points) is that they should lead
to a more flexible TAC setting environment, rather than setting specific TACs based on the notion of
maximum yields. The key issues driving TAC setting will become economic, marketing and other
considerations, provided the recommended catch level would not lead to a violation of the ESD objectives
for a species. This will enable AFMA, SETMAC and SENTMAC to embark on a more strategic approach
to TAC setting, which should lead to more stability in future catch levels.
Further development of strategies to reduce bycatch, the environmental impact of gear, high levels of
discarding and strategies to address input controls to prevent growth overfishing (eg. mesh size control)
will be undertaken by AFMA, SETMAC and SENTMAC in the future. In the long-term, it is envisaged that
other environmental objectives relating to ESD, such as protecting critical habitats, will be developed.
During 1997 and early 1998 AFMA, SETMAC and its Research Sub-committee revised the SEF Strategic
Research Plan (SEF Strategic Research Plan 1997-2002, April 1998). This plan has set the strategic
direction for SEF related research, including the type of stock assessment to be carried out for each of the
quota species each year, as determined by the Assessment Groups in the SEF. To support these stock
assessments, the timing of required data collection to conduct the assessments and the special research
projects needed to support the assessments, are also included in the Plan.

22                                                               SEF Fishery Assessment Report 1999
AFMA management sought and received endorsement by the AFMA Board and SETMAC of the
objectives, strategies and performance indicators for the management of orange roughy during 1994-95.
SETMAC also endorsed the objectives, strategies and performance indicators for the management of the
remaining quota species.
The CPUE strategy is useful if, and only if, CPUE is an effective indicator of stock status or abundance.
Obviously, the usefulness of a CPUE index will depend on the degree to which factors other than fish
abundance influence changes in catch rates. For example, environmental influences, fishing practice
influences, market influences, changes in management regulations and trends in technological change can
each and together result in CPUE being an unreliable indicator of stock status / abundance. It should be
noted that for some species generalised linear models have been employed to produce standardised indices
of CPUE. However, it is certainly not clear-cut as to when the CPUE strategy is useful and when it is not.
More broadly, the CPUE strategy was criticised for not being explicit about how the performance indicator
could be achieved, nor what response would be made if the indicator is triggered. This is critical to the
management process, in that stakeholders will know the ―rules‖ up front, rather than attempting to get
agreement to management contingencies at the time crucial action is required to protect a fish stock
The use of the CPUE strategy was also questioned where a stock was either already depleted, or lightly
exploited. In the former scenario the strategy implies that it would be acceptable to maintain the stock in a
depleted state. In the latter scenario the resource could not be developed as this could result in a decline in
CPUE.
In 1998 SEFAG and a number of the species-specific Assessment Groups in the SEF began to develop
alternative strategies and performance indicators for specific SEF quota species, and blue grenadier and
blue warehou in particular. This development will continue for a number of SEF quota species. In parallel
to this process, and as part of research project by CSIRO beginning in 1998, robust harvest strategies and
performance indicators will be developed for a group of SEF species for which relatively little data exists.
At a broader level, it would be appropriate that strategies and performance indicators for SEF quota
species, the environment and economic efficiency within the SEF be developed as part of a Management
Strategy Evaluation approach.
Thus, an important task to be undertaken by AFMA, SETMAC and SENTMAC, in consultation with
SEFAG and the species-specific Assessment Groups, is the formal revision of strategies and performance
criteria / indicators for the SEF.


4.     SOURCES AND STATUS OF DATA
The SEF operates in Commonwealth waters adjoining five States: Queensland, NSW, Victoria, Tasmania
and South Australia. Historically, the cooperation between fisheries agencies from the States and the
Commonwealth was limited for both management and research. Virtually all data collection and research
on SEF species during the 1960s and 1970s was carried out by State fisheries authorities, with little overall
coordination. The Demersal and Pelagic Fish Research Group (DPFRG), which was formed in 1975 and
disbanded in 1994, played an increasingly prominent role in SEF research issues. Prior to the formation of
the Fishery Assessment Group (SEFAG) in 1993, DPFRG conducted and reviewed the 1991 and 1992
stock assessments at the request of the (then) Australian Fisheries Service.
It has been compulsory for SETF (trawl and Danish seine) fishers to complete a shot-by-shot logbook since
October 1985. However, collection of catch and effort data from other sectors still remains a major
problem, with no formal structure in place to collate and check data from the different fisheries from which
SEF quota species are taken. The timeliness of data collection varies between States. A Commonwealth
non-trawl logbook system was implemented on 1 January 1997.
Before the introduction of the trawl ITQ system in 1992 and the consequent involvement of the SEF
logbook with the quota monitoring process, data analyses and targeted validation studies indicated most
(>80 per cent) logbook data to be of good quality. Since ITQ management commenced, logbook data
quality has declined. Two main types of error have occurred:

1. Under-reporting by not stating catches of quota species on either the logbook (SEF1) or landing (SEF2)
   forms. This occurred mainly during 1992 when initial surveillance measures were lacking, but still
   continues on a lesser scale.



SEF Fishery Assessment Report 1999                                                                            23
Table 6. Mean percentage by weight of total landings for each species reported from waters less than 100 m (Data
source: AFZIS, SEF1 Logbook data 1986-97)

                      SPECIES                1986-1991        1992-1995         1996-1997
                      Blue eye trevalla         4.6              2.9               0.1
                      Blue grenadier            0.4              0.3               0
                      Blue warehou             42.6             47.1              10.6
                      Gemfish                   1.3              2.7               0
                      Jackass morwong          73.3             79.6               6.1
                      John dory                82.0             94.5              30.7
                      Ling                      3.4             12.5               0.4
                      Mirror dory               1.5              3.4               0.4
                      Ocean perch               4.2              8.0               0.2
                      Orange roughy             0.1              0.1               0
                      Redfish                  56.9             71.3               4.0
                      Royal red prawn           0.2              0.1               0
                      School whiting           97.5             99.9              97.4
                      Silver trevally          89.6             96.8              70.0
                      Spotted warehou          19.0             33.0               1.3
                      Tiger flathead           76.5             88.0              40.3


2. Misreporting of where quota species were caught. This was particularly prevalent off NSW, because of
   split jurisdictional arrangements under OCS agreements with this State, until State trip-limits were
   introduced. Although catch tonnage and effort may be recorded correctly, incorrect positional data will
   confound spatial analysis. Off Tasmania and Victoria the misreporting of orange roughy caught in one
   management zone as coming from another management zone was a common practice before the
   compulsory introduction of satellite transponders to the orange roughy fleet in 1994.

Table 6 compares the mean percentage of landed weight of each quota species reported as coming from
waters less than 100m (it is assumed that the 100m isobath approximates the 3 nm State boundary) before
and after the introduction of ITQ management and after the introduction of State trip limits. In 1992/95,
significant ―shifts‖ into State waters occurred for ling, redfish and spotted warehou, and to a lesser extent
for several shelf species. The introduction of State waters trip limits for many quota species then reduced
the incidence of misreporting Commonwealth catches from these waters after 1995. The marked reduction
in blue warehou, jackass morwong, John dory, redfish and flathead in 1996/97 (Table 6) also suggests that
genuine effort also shifted out of State waters after 1995. Analysis of fishing effort distribution by depth off
NSW (using the SEF logbook database) shows a marked ―shift‖ in the recorded effort peak from the 50-99
m depth stratum to the 100-149 m stratum (i.e. from State to Commonwealth waters) from 1995 onwards.
Prior to 1992, the 100-149 m stratum was always the most heavily fished depth zone (Tilzey 1994).


Although data from the landing forms (SEF2 (trawl) and SAN2 (non-trawl)) are usually taken as the most
accurate record of landed catch for the quota species, the logbook (SEF1 (trawl) and GNO1 (non-trawl))
data remain one of the main sources of information for stock assessment. A shot-by-shot record is essential
in a complex multi-species fishery in which targeting of different species does occur. Catch and biological
data collected by State agencies throughout the history of the fishery are also being collated and used by
SEFAG. This information underpins all stock assessments and modelling of the SEF fishery and forms the
basis for the biological input into the setting of TACs for the fishery.
In the absence of fisheries independent data for most species, future stock assessments and risk assessment
of management options will be heavily reliant on the accuracy of Commonwealth and State logbook data.
Whereas (pre-ITQ) targeted validation studies that compared landed catches with logbook records found, in
most instances, good correlation between catch weights by species, only onboard monitoring can validate
logbook effort data. The CPUE analyses used thus far for SEF stock assessments assume that logbook
effort data are accurate as no means currently exists, other than direct onboard observation, of verifying
these data.




24                                                                 SEF Fishery Assessment Report 1999
A study compared aggregated data collected by logbooks and the quota monitoring system. In general, the
trends seen in these data agreed reasonably well, except for a few species where reasons for the
discrepancies were obvious (e.g. reporting catches from Commonwealth waters as taken in State waters).
However, any misreporting that is consistent across the two sets of data would not be detected by this
comparison.
Between 1993 and 1997 the Scientific Monitoring Program (SMP) collected valuable data from the trawl
sector of the SEF. Information on fishing practices (e.g. targeted species and quantitative composition of
retained and discarded catches) was collected through a combination of on-board and port based sampling.
The program was managed by the BRS and coordinated by a steering committee comprising members from
BRS, CSIRO, AFMA, the Victorian, NSW and Tasmanian fisheries agencies and the SEF trawl industry.
The SMP complemented a NSW bycatch monitoring study funded by the Fisheries Research and
Development Corporation (FRDC).
Acknowledging a continuing need to collect these important data and a need to integrate activities, an
Integrated Scientific Monitoring Program (ISMP) under contract to the Victorian Marine and Freshwater
Research Institute is now in place. Routine sampling by the ISMP is conducted across the fishery. Data
collected by the ISMP includes total catch (retained and discarded) of quota species, species and size
composition of retained and discarded catches and information on fishing practices. The ISMP also
facilitates the collection of otoliths for the Central Ageing Facility.
The Central Ageing Facility (CAF), a national fish ageing laboratory established at the then Victorian
Fisheries Research Institute in 1991, is the primary source of age and growth data for input to the SEFAG
annual stock assessment process for SEF species. CAF routinely produces reports for each species that
include mean length-at-age, growth parameters and age-length keys. These data can then be used in
conjunction with length frequency data to provide estimates of the age composition of SEF catches.
Various research projects conducted by CSIRO, BRS and State agencies provide crucial input in specific
areas identified through the stock assessment process. For example, results from recent trawl surveys
conducted by the NSW FRV Kapala were used in some 1998 assessments. SEF-based projects are
prioritised by SETMAC and its Research Sub-Committee. The non-trawl sector is also involved in
assessing these projects and has representatives on this Sub-Committee and SEFAG. Fisheries agencies
such as CSIRO and those of the States also apply their own priorities and these do not necessarily align
with those of SETMAC. The funding for SEF research projects is mainly provided through agency core
funding, the FR&DC, the AFMA Research Fund (ARF) and DPIE‘s (now AFFA‘s) Fisheries Resources
Research Fund (FRRF).
Industry opinion and fisher‘s knowledge have been recorded either by industry‘s direct involvement with
Assessment Groups, or during the annual port visits conducted by SEFAG. In 1997/98 a FRDC funded
study also collected details of gear and fishing practices across the trawl fleet.
Economic data are collected on fish prices, costs and returns from fishing, and the economic structure of
the SEF. Time series information on the costs and returns of the fishery is obtained through annual fishery
economic surveys conducted by ABARE. This information is available for the years 1989-90 to 1996-97,
and is published in ABARE‘s series of fishery survey reports. ABARE also obtains price information from
various State agencies, fishing cooperatives, processors and marketing authorities. Monthly price and
throughput information from both Sydney and Melbourne markets has been collected since 1990. Although
economic data for the SEF fishery are relatively comprehensive, data for non-SEF fisheries impacting on
quota stocks are limited.


5.     PREVIOUS STOCK ASSESSMENTS
In 1993, the newly formed SEF Assessment Group began preparing stock assessments for each quota
species based on all available information. The information was derived from a variety of sources including
specific workshops (redfish and blue grenadier) and assessments provided by State agencies. A Fishery
Assessment Report was produced, but only one Stock Assessment Report (redfish). For the remaining
species, both a lack of adequate data and the limited time available prevented any detailed stock assessment
in 1993.
In 1994, the status of all the quota species was assessed through a series of working groups and meetings of
the SEFAG. In addition to the 1994 Fishery Assessment Report, a Stock Assessment Report was produced



SEF Fishery Assessment Report 1999                                                                         25
for each species documenting the available information. However, for most species there was very little
formal modelling or analysis.
Having established a baseline with the publication of the 1994 Stock Assessment Reports, SEFAG was able
to take a more strategic approach in 1995 and concentrate on species previously determined to be high
priority by SETMAC. Stock Assessment Reports were prepared for blue grenadier, ling, eastern gemfish,
blue warehou, redfish, orange roughy, blue eye trevalla, jackass morwong and king dory (a non-quota
species). For the remaining quota species, the Stock Assessment Summary in the Fishery Assessment
Report was updated with the latest available catch information (1994), but there was no new assessment. A
five-year plan was established for scheduling future assessments. The plan, which is subject to revision
each year, is intended to guide the timing of particular research and modelling activities and enable future
assessments to be based on significant new analyses. A set of criteria was developed in 1995 for
determining the broad types of assessment techniques that should be applied to each species. The criteria,
which are listed in Appendix 3, consider biological characteristics, fishing practices and economic and
social significance and were used to identify data collection needs for each species.
The 1996 assessment was developed through a workshop on flathead, a planning meeting, port meetings
with industry and the SEFAG annual plenary meeting. Stock Assessment Reports were prepared for blue
warehou, flathead, eastern gemfish, john dory, mirror dory, ocean perch, orange roughy and oreo dories.
SEFAG developed 5-year research plans for each species identifying what research is needed and when to
ensure that there is appropriate information on which to base a stock assessment. SEFAG attempted to
respond to a request from SETMAC to suggest why TACs were not reached for many species. This proved
to be a major undertaking and SEFAG decided to defer this assessment until results from a proposed
ABARE study on quota holdings and quota trading are available. Possible reasons for not reaching a TAC
include low stock abundance, environmental influences on fish availability/catchability, market factors,
quota availability and interactions with other species (for example, when a species is caught mainly as a
bycatch of other species). Distinguishing between these possibilities for a given species may require
substantial research.
In the 1996 assessment, SEFAG noted that five species had failed to satisfy AFMA‘s catch rate
performance criteria in 1995. They were blue warehou, western gemfish, jackass morwong, mirror dory and
redfish. Based on logbook data and using only shots containing the species in question, the 1995 catch rates
for these species were at their lowest since 1986. SEFAG, where appropriate, brought forward planned
stock assessments for these five species. Available evidence suggested that the eastern gemfish stock was
still below AFMA‘s target of 40 per cent of the 1979 spawning biomass, but improving. Experimental
fishing of the 1996 gemfish spawning run to obtain a clearer picture of stock status was recommended. The
1996 assessment of orange roughy was less optimistic than the 1995 assessment, regarding the rate at which
the stock was rebuilding under the strategic TAC scenario. An alternative TAC scenario was proposed to
meet AFMA‘s performance criterion. SEFAG also noted with concern the high discard rates for several
quota species, especially blue warehou, flathead, ocean perch and redfish. As well as complicating
assessments, discarding places additional fishing pressure on the stock and probably reduces future benefits
to fishers. The need to identify practical means of reducing discard rates was stressed. SEFAG also
expressed concern at the rising trawl effort in the fishery.
The 1997 assessment was developed through workshops on western gemfish, redfish, blue grenadier,
orange roughy (twice) and blue warehou. An Eastern Gemfish Assessment Group (EGAG) was established
in 1996 and this met on five occasions during the 1996/97 financial year. A SEFAG planning meeting was
held on 13 February 1997 and the SEFAG Plenary meeting on 23-27 June 1997, both at BRS, Canberra. Dr
Pascale Baelde was commissioned to re-examine the Tasmanian blue eye trevalla fishery and undertook
field work for this purpose during April 1997. Port meetings were held over the period 7-16 April 1997.
Full stock assessments were not conducted for the other quota species, but their status was updated using
1996 catch data, SMP data, input from the port visits and any new information available. All stock
assessment summaries were reviewed at the SEFAG plenary.
The western gemfish workshop centred on examining catch rates, both for the whole fishery and individual
vessels, and found that this fishery had improved in 1996, rising above AFMA‘s catch rate performance
criterion. The redfish workshop did not produce a formal assessment, centering on arriving at an agreed
catch history with industry and developing a strategic approach to future assessments. It was generally
agreed that redfish undergo cyclic fluctuations in abundance and that, since 1993, the fishery is on a
downward cycle. Differences in growth rates between redfish sampled at Ulladulla and Eden suggested
some structuring within what is thought to be a common stock. The blue grenadier workshop centered on
the reanalysis of data from the 1995 egg production survey which yielded a best estimate of a spawning

26                                                             SEF Fishery Assessment Report 1999
biomass of about 102 000 t. This is of the same order as a 1994 acoustic estimate, but significantly lower
than the estimate from an earlier analysis of the survey data (about 250 000 t). The initial orange roughy
workshop examined catch data from the three management zones and the Cascade Plateau and the results of
a 1996 acoustic survey of St Helens Hill. In general, catch rates had significantly declined in the southern
and eastern management zones, but remained comparatively steady in the western zone. Little could be
deduced from limited Cascade Plateau data. The results of the acoustic survey, which showed a significant
decline in biomass, were disputed by industry which claimed that a large proportion of the ―St Helens‖ fish
were on the Paddy‘s Head grounds at the time of the survey. The second workshop noted that it now
appears probable that a significant proportion of fish in the Eastern and Southern comprise a common
migratory stock and the combined zone assessment should be given more weight. It further noted that even
if the 1996 acoustic data are omitted, reanalysis of earlier data indicates that annual catches in the
combined zones should be reduced to 2000 t from 1998 onwards under the risk adverse strategy endorsed
in 1996. Industry did not accept this assessment, claiming that no significant new survey data had been
collected since the 1994 assessment. The blue warehou workshop confirmed that this fishery is in decline,
with downturns in both the trawl and non-trawl sectors and a significant reduction in the representation of
adult fish in the trawl catch. For blue eye trevalla, Tasmanian catches were significantly higher (45 per cent
by weight) in 1996 compared with 1995, but it was unclear if this increase was caused by an upsurge in
effort before ITQ management is introduced in 1998, improvements in gear technology, an increase in fish
abundance, or a combination of these factors.
Five of the quota species triggered AFMA‘s catch rate performance criterion in 1996; blue warehou,
jackass morwong, mirror dory (all for the second year in a row), John dory and school whiting. SEFAG
noted that catches of the latter species are largely market driven. SEFAG again expressed concern at the
continued rise in trawl effort in the fishery (up a further 7.5 per cent from 1995 to 1996) and noted that this
would probably trigger the catch rate criterion for other species in the future if the rise continues. In 1996,
discard rates continued to be high for flathead, mirror dory and ocean perch, increased significantly for blue
grenadier, but decreased significantly for blue warehou and redfish (in the latter case, probably because of
the introduction of a NSW State trip limit). SEFAG again stressed the need for gear selectivity studies to
reduce bycatch and discarding rates.


6.     1998 STOCK ASSESSMENT PROCESS
The 1998 assessment was developed principally through workshops and meetings held by the individual
Fisheries Assessment Groups. Four new FAGs were established at the start of the 1997/98 financial year to
assess blue grenadier (BGAG), blue warehou (BWAG) orange roughy (ORAG) and redfish (RAG). The
eastern gemfish group (EGAG) continued as before. A SEFAG planning meeting was held on 11-12
November 1997 at the BRS, Canberra and the SEFAG Plenary meeting on 6-10 July 1998 at the AFMA,
Canberra. SEFAG also held an Economic Workshop on 6 February 1998 at AFMA. FAG meetings were
held on the following dates during the 97/98 financial year;
BGAG           20-21/1/98     15-16/4/98      1-1/6/98
BWAG           25/11/97       19-20/1/98      14-15/4/98     30-31/5/98
EGAG           10-12/9/97     13-14/11/97     19-20/3/98
ORAG           11/8/97        16-17/3/98      28-29/5/98
RAG            20/11/97       30/1/98         12/5/98        25/6/98
Drs Pascale Baelde and Jeremy Prince were commissioned to conduct port visits. It had previously been
decided that attempting to cover the entire fishery did not allow sufficient time for dialogue in each port.
Consequently, the eastern and western (including Tasmania) halves of the fishery would be visited in
alternate years, commencing with the eastern half in 1998. Port meetings were held at Sydney,
Wollongong, Ulladulla, Bermagui, Eden and Lakes Entrance during April 1998. A summary of the
discussions at these meetings was prepared for the SEFAG Plenary. Dr Baelde also presented a summary
of a recent FRDC funded survey of fishing practices in the SEF trawl sector.
Quantitative assessments were conducted for blue grenadier, blue warehou and redfish by their Assessment
Groups. Whereas a quantitative assessment was also conducted for orange roughy, this was not agreed to by
ORAG industry members. A quantitative assessment will also be conducted for eastern gemfish by EGAG
after the 1998 survey of the winter spawning run is completed. Consequently, the eastern gemfish summary
is not included in this report. No quantitative assessments were conducted for the other quota species. The


SEF Fishery Assessment Report 1999                                                                          27
authors of the stock assessment reports and update reports are listed in the Acknowledgments Section. All
stock assessment summaries were reviewed at the SEFAG plenary. Data from the CAF (Sandy Morison et
al.) the SMP (John Garvey and Geoff Liggins) and the ISMP (Ian Knuckey) were central to the assessment
process.
There were five species/species groups which triggered AFMA‘s catch rate performance criterion in 1997;
namely, John dory, mirror dory, ocean perch, school whiting and spotted warehou. SEFAG resources were
mainly directed towards updating the stock assessment reports for these five species and those for blue eye
trevalla and ling. Comparatively little attention was paid to the remaining five quota species; flathead,
jackass morwong, royal red prawn, silver trevally and western gemfish. The main data sources used were
the SEF2 and SEF1 databases, the SMP/ISMP and, where appropriate, the results from a recent fishery
independent trawl survey by the FRV Kapala between Sydney and Gabo Island.
Following the SEFAG planning meeting, a submission to AFMA was prepared seeking funding to hold blue
eye trevalla and ling workshops in 1998/99. One aspect of these workshops would be to assess if
information availability justified the creation of Assessment Groups for these species. The submission was
successful and funding was made available for 1998/99.



7.     ECONOMIC STATUS

The south east fishery is Australia‘s major scale fishery supplying the bulk of New South Wales, Victorian,
Tasmanian and South Australian fresh fish requirments. A large number of commercial and non
commercial species are caught in this complex multispecies fishery. The catch is concentrated in the
sixteen major species that have been under individual transferable quota since 1992. Seven species
constitute about two-thirds of the trawl catch. Orange roughy is still the major species landed but its share
of the trawl catch continues to decline. In the non trawl sector of the fishery, blue eye trevalla is the major
fish species taken.

Landings by Commonwealth trawlers operating in Commonwealth and state waters totalled 28 003 tonnes
in 1998, compared to 29 570 tonnes in 1997. Catches by the non trawl sector of blueeye trevalla, blue
warehou and ling totalled 855 tonnes in 1998, similar to 1997 landings.

The gross value of production of quota species taken by Commonwealth endorsed boats trawling in the
Commonwealth and state waters of the south east fishery in 1998 is estimated to be about $46.8 million, a
fall of 10 per cent from the previous year. The total value of other species taken by trawling in
Commonwealth and state waters is around $9.6 million, 21 per cent higher than in the estimated value in
1997. This increase is due to rises in returns to fishermen (table 4).

While TACs and ITQs have been in place for the trawl component of the fishery since 1992, in the non
trawl sector three species only — blue eye trevalla, ling and blue warehou are subject to TACs. In 1998
the value of these species taken by the non trawl sector was $3.5 million ($2.7 million in 1997). Landings
of other fish species (excluding shark) by this sector for 1998 were valued at $XX million.

The south east fishery continues to be an important component of the Australian fishing industry, taking
the largest tonnage and supplying most of the fresh fish for the Sydney and Melbourne markets. It
currently supplies around 20 per cent of domestic fish catches (Smith 1997). While most of the catch taken
in the south east fishery is consumed domestically, and forms the base of the Sydney and Melbourne fish
markets, both orange roughy and whiting are exported.

In 1998 the US imported 10 248 tonnes of frozen orange fillets of which Australia supplied 1426 tonnes.
Exports to Japan of whiting (frozen whole from Victoria) fell in 1998 to 57 tonnes, compared to 112
tonnes in 1997. Average export returns remained relatively unchanged in 1998 at $2.32/kg, compared to
$2.39/kg in the previous year.

Australia does import a substantial quantity of fish and fish products. In 1998 total imports of fresh and
frozen fish (excluding tuna and salmon) were around 48 200 tonnes (product weight) valued at around


28                                                               SEF Fishery Assessment Report 1999
$195 million. Major suppliers to Australia are Chile and Cayman Islands for hake products and New
Zealand for other chilled and frozen fish. In 1998, imports of south east fishery quota species from New
Zealand were at least 9900 tonnes (product weight). The major species imported from New Zealand is blue
grenadier (hoki) 6075 tonnes (product weight) in 1998, up 2000 tonnes from 1997.


Recent economic developments

TOTAL ALLOWABLE CATCH LEVELS
Total allowable catch levels agreed and allocated by AFMA are given in table X. Notably, the agreed total
allowable catch for targeted fishing of eastern gemfish was zero between 1993 and 1996, while the agreed
total allowable catch for orange roughy was reduced from 17 500 tonnes in 1992 to 4500 tonnes in 1997
and 1998. Between 1992 and 1998, the agreed total allowable catch for all species excluding orange
roughy increased by 62 per cent. For all quota species, excluding orange roughy, the agreed total allowable
catch increased most significantly in the first two years of the new arrangement from 17 390 tonnes in
1992 to 25 465 tonnes in 1994 and then increased more slowly to 28 231 tonnes in 1998. In 1998, the
agreed total allowable catch for only three species — blue warehou, eastern gemfish and orange roughy —
was below the landings recorded in 1991.

The allocated total allowable catch is the agreed total allowable catch after adjusting for carryover/under
arrangements and some adjustments to initial allocations. The allocated total allowable catch for all
species excluding orange roughy rose by 81 per cent from 18 091 tonnes in 1992 to 32 676 tonnes in 1998.
In 1998, the allocated total allowable catch exceeded the agreed total allowable catch for all species except
eastern gemfish, ling, orange roughy and spotted warehou.

LANDINGS OF QUOTA SPECIES (IN THE TRAWL SECTOR)
Landings of quota species from Commonwealth and state waters of the south east trawl fishery are
presented in table 2. Fluctuations in landings of orange roughy have had a major impact on total landings
of quota species from the south east fishery. Reflecting changes in both species abundance and the total
allowable catch, orange roughy landings declined from a peak of 41 239 tonnes in 1990 to 16 488 tonnes
in 1992 to 2580 tonnes (an additional 1594 tonnes was caught off Cascade Plateau and Remote zone). As a
share of total landings of quota species, orange roughy landings have declined from a peak of 75 per cent
in 1990 to 18 per cent in 1998.

Excluding orange roughy landings from all zones, total landings of quota species in the trawl sector have
increased by 36 per cent from 13 709 tonnes in 1992 to 18 650 tonnes in 1998. Annual landings of several
species have increased markedly between 1992 and 1998, including ling (158 per cent), mirror dory (102
per cent), blue grenadier (74 per cent) and spotted warehou (229 per cent). By contrast, annual landings
have declined significantly for orange roughy, school whiting, john dory and blue warehou




SEF Fishery Assessment Report 1999                                                                         29
 Table 2 Landings of quota species by south east fishery trawl operators (Commonwealth and state waters



Species                       1992        1993       1994        1995        1996       1997         1998

                                   t          t           t          t           t           t            t
Catch
Blue eye trevalla               61          78          91         68          81        113            96
Blue grenadier               3 289        3359       3 155      2 761       3 039      4 538         5 734
Blue warehou                   934         979       1 073        951         854        794           932
Flathead                     2 751        2160       1 952      2 033       2 114      2 677         2 543
Gemfish                        705         402         281        221         325        624           399
  Gemfish eastern              579         267         143         97         117        397           214
  Gemfish western              126         135         138        124         208        227           185
Jackass morwong                818        1080         890        853         896       1136           883
John dory                      155         264         292        208         187        103           127
Ling                           655       1 036       1 047      1 410       1 449      1 756         1 692
Mirror dory                    211         331         322        280         403        546           426
Ocean perch                    202         332         303        315         356        423           363
Orange roughy a             16 488      10 672       6 962      5 172       4 983      5 715         4 174
                 East        7 423       1 957       1 682      1 958       1 998      2 063         1 968
                South        7 911       7 683       4 353      2 159         802        454           251
                West          1154       1 032         927      1 055       1 319        352           361
   Remote and Cascade                                                                                1 594
Redfish                       1 784      2 071       1 620      1 333       1 548      1 597         1 770
Royal red prawn                 180        295         386        357         404        295           282
School whiting                  871      1 784       1 012      1 271         997        754           638
Silver trevally                 360        454         461        467         418        372           233
Spotted warehou                 733      2 145       2 644      2 427       2 563      2 785         2 411

Total                        30197      27 442     22 491      20 127      20 614     24 229       22 824

 Less orange roughy          13709      16 770     15 529      14 955      15 634     18 513       18 650


 PRICES OF QUOTA SPECIES
 Marketing and pricing of fish supplied by the south east fishery is described in Smith, Griffiths and Ruello
 (1998). In this study it was found that prices formed at the Sydney fish market for the major high volume
 species from the inshore sector of the fishery are relatively responsive to changes in the volume sold. This
 response was found to be similar for redfish, school whiting, silver trevally and tiger flathead, with the
 expected price rising by around 6 per cent with each 10 per cent fall in the volume sold.

 Prices for other quota species from the south east fishery were found to be less responsive to volume
 changes. The likely response to a 10 per cent fall in volume ranged from a price increase of 4 per cent for
 silver warehou and 3 per cent for morwong, down to a 1 per cent increase in prices for ling. That is, for
 these species, less of the volume effects of a reduction in catch would be offset by price increased.
 Conversely, any increased in production and marketing of the species would result in small falls in
 wholesale prices than for the high volume species.

 Prices of quota species, in 1998 dollars, based on quantity weighted average monthly prices from the
 Sydney and Melbourne fresh fish markets are given in table 3. The total unit price (quota species) declined
 by 23 per cent from $2.65 a kilogram in 1992 to $2.05 a kilogram in 1998. Between 1992 and 1998, the
 total unit price across all species fluctuated but has declined 16 per cent overall to $2.01 a kilogram in1998
 (table 3).



 30                                                              SEF Fishery Assessment Report 1999
Table 3 Prices by species (in 1998 dollars)
Species                                1992          1993          1994      1995        1996   1997    1998

                                       $/kg          $/kg          $/kg          $/kg    $/kg   $/kg    $/kg

Blue eye trevalla                      4.82          4.20          5.00          5.46    5.33   4.44    6.19
Blue grenadier                         2.35          2.27          2.44          2.45    2.53   2.20    1.54
Blue warehou                           1.86          2.00          1.90          2.27    1.96   1.90    1.76
Flathead                               1.75          1.86          1.99          1.65    1.85   1.65    1.92
Gemfish                                3.02          3.04          3.19          3.92    3.54   2.67    3.04
Jackass morwong                        1.86          2.02          2.04          1.95    1.87   1.52    1.61
John dory                              5.65          4.08          4.39          5.97    5.72   6.12    5.43
Ling                                   3.28          3.02          3.30          3.11    3.30   2.91    3.33
Mirror dory                            1.33          2.01          1.90          1.87    1.75   1.75    1.94
Ocean perch                            2.43          2.52          2.63          2.56    2.76   2.68    2.58
Orange roughy                          3.03          3.38          3.47          2.95    2.53   2.91    3.04
Redfish                                1.11          0.92          1.11          1.13    1.04   1.12    1.07
Royal red prawn                        2.82          2.74          2.82          3.49    2.90   2.77    3.69
School whiting                         1.25          1.24          1.37          1.50    1.31   1.58    1.68
Silver trevally                        1.26          1.25          1.30          1.38    1.44   1.51    1.57
Spotted warehou                        1.55          1.34          1.24          1.23    1.15   1.41    1.16

Quota species unit value               2.65          2.50          2.50          2.27    2.15   2.17    2.05

Unit value across all species          2.39          2.37          2.48          2.15    2.04   2.05    2.01

a Beach or landed prices
Source: Average monthly prices from the Melbourne and Sydney fish markets.



GROSS VALUE OF LANDINGS
Reflecting lower earnings from orange roughy, the gross value of landings of all species by south east
trawl operators in Commonwealth and state waters, in 1998 dollars, has declined from $84.5 million in
1992 to $56.3 million in 1998 (table 4).

Table 4 Value of landings in the south east trawl fishery (in 1998 dollars)


Species                         1992          1993          1994          1995          1996    1997       1998

                                 $m            $m            $m            $m            $m       $m            $m

Blue eye trevalla                0.3           0.3           0.5           0.4           0.4      0.5           0.6
Blue grenadier                   7.7           7.6           7.7           6.8           7.7     10.0           8.8
Blue warehou                     1.7           2.0           2.0           2.2           1.7      1.5           1.6
Flathead                         4.8           4.0           3.9           3.4           3.9      4.4           5.1
Gemfish                          2.1           1.2           0.9           0.9           1.2      1.7           1.2
Jackass morwong                  1.5           2.2           1.8           1.7           1.7      1.7           1.4
John dory                        0.9           1.1           1.3           1.2           1.1      0.6           0.7
Ling                             2.1           3.1           3.5           4.4           4.8      5.1           5.6
Mirror dory                      0.3           0.7           0.6           0.5           0.7      1.0           0.8
Ocean perch                      0.5           0.8           0.8           0.8           1.0      1.1           0.9
Orange roughy                   50.0          36.1          24.2          15.2          12.6     16.7          12.7
Redfish                          2.0           1.9           1.8           1.5           1.6      1.8           1.9
Royal red prawn                  0.2           0.2           0.4           0.4           0.4      0.3           1.0


SEF Fishery Assessment Report 1999                                                                             31
School whiting                 1.1              2.2      1.4           1.9         1.3          1.2          1.1
Silver trevally                0.5              0.6      0.6           0.6         0.6          0.6          0.4
Spotted warehou                1.1              2.9      3.3           3.0         3.0          3.9          2.8

Total quota species          76.8              67.0    54.6           44.8       43.5         52.1         46.8
less orange roughy           26.9              30.8    30.4           29.6       31.0         35.5         34.1

Total all species            84.5              78.2    67.6           52.5       50.5         60.5         56.3




FLEET PROFITABILITY
Based on ABARE survey data in Brown (1997), the real rate of return to capital assets (excluding licences
and quota) tends to be highest for offshore trawlers with an average of 34 per cent between 1992-93 and
1996-97. The average real rate of return during the same period was 14 per cent for inshore trawlers and 3
per cent for Danish seiners. Average boat profitability has declined in all sectors of the fishery in recent
years — from 38 per cent in 199192 to 23 per cent in1996-97 for offshore trawlers, 12 to 10 per cent for
inshore otter trawlers and 26 to 5 per cent for Danish seiners (table5). In 1999 ABARE is undertaking an
economic survey of both trawl and non trawl sectors of the south east fishery. The results of the survey will
be available by the end of 1999.

The profitability of the offshore fleet has declined as a consequence of the large reduction in the orange
roughy catch, but remains high relative to the inshore fleet mainly due to a substantial fall in the number of
boats and increased revenue from harvesting blue grenadier. By contrast, the number of boats in the
inshore fleets, particularly inshore trawlers, has increased since the introduction of individual transferable
quotas. Relatively slow adjustment in the inshore fleet may partly be due to the prolonged litigation over
quota allocations and limited opportunities to move to other fisheries since the number of fisheries subject
to limited entry has increased.

Following a review of the fishery in 1996 the Commonwealth government announced the introduction of a
$6.9 million adjustment plan in September 1997 to facilitate structural adjustment in the south east fishery
(Parer 1997). In 1998, $2.3 million was disbursed to sixteen operators whose asset holdings were assessed
to be unfairly reduced by the transition from boat units, and $1.7 million was disbursed to 27 operators
who elected sell their permits. The impact of this adjustment package on the fishery is currently being
assessed.

Table 5 Rates of return and number os boats in the south east fishery (trawlers only)
                                     Danish               Inshore            Offshore           Fleet
                                     seiners             trawlers            trawlers         average

                                          %                      %                 %                  %

1989-90                                16.0                    20.5             27.3              21.0
1990-91                                20.5                     9.8             10.1              10.5
1991-92                                26.3                    11.9             38.3              30.0
1992-93                                 3.7                    30.1             44.7              37.4
1993-94                                 5.8                    19.0             48.3              35.6
1994-95                                -0.8                     5.0             41.1              18.1
1995-96                                -0.1                     6.2             14.7               9.1
1996-97                                 5.0                     9.7             23.0              14.6

Average:
1992-93 to 1996-97                       2.7                   14.0             34.3              22.9
Source: Hogan, Thorpe and Timcke 1999; Brown 1997 and previous issues.




32                                                                SEF Fishery Assessment Report 1999
SOUTH EAST FISHERY QUOTA MARKET
While single species are traded, it is more common for transfers to involve the negotiation of a package of
quota covering a number of different species. Permanent quota trading was restricted from March 1992 to
January 1994 such that only full quota buyout were permitted. This may have reduced the efficiency of the
system during this period by not allowing operators to adjust the scale of their operations through the partial
transfer of quota. The main adjustments to permanent quota holding occurred in 1994, Overall, the volume
of permanent quota transactions increased from 1346 tonnes in1992 to a peak of 6119 tonnes in 1994 and
has since declined to 628 tonnes in 1997 (Hogan, Thorpe and Timcke 19990 (table 6).


Table 6 Volume of permanent quota transfers in the south east fishery

Species                       1992      1993      1994       1995        1996       1997      Average

                                   t         t        t           t          t           t            t

Blue eye trevalla                 3       12        28          6           4           0            9
Blue grenadier                  181      465      1459        266         173          13          426
Blue warehou a                    0      145       234        189           5          46          103
Flathead                        162      280       503        292         224          39          250
Gemfish eastern                  14       17        35          7           1           9           14
Gemfish western                   1       47         5         20           1          50           21
Jackass morwong                 142      172       349        121          47          30          143
John dory                         9       31        55          7           1          36           23
Ling                             48       59       193         52          49          91           82
Mirror Dory                      23       87       107         46          15          24           50
Ocean perch                      16       11       102         35           2          34           33
Orange roughy east              117      136       353        179          78           –          172
Orange roughy south             304      904      1069        100          48           1          404
Orange roughy west               79      137       311         29          38           0           99
Redfish                          40       78       178         99          17           5           70
Royal red prawn                  10       38        13          6           1          10           13
School whiting                   13      160       516        210          92          63          176
Silver trevally                  25       49       132         28           1          10           41
Spotted warehou a               161      291       477        231          73         166          233

Total a                       1346      3119      6119       1923         869         628         2334
Average b                       46       284        57         44          30          39           59
Share of total quota c%          4         9        15          5           2           2            6
a Blue and spotted warehou treated as a single species in 1992. b Total volume of permanent quota transfers divided
by the total number of quota lease transactions in the corresponding period. Transfers of packages of quota have been
treated as single transfers. c Share of total allocated quota holdings.
Sources: Hogan, Thorpe and Timcke 1999; AMFA quota monitoring system.


Most quota trade in the south east fishery has been through lease transactions. In aggregate the volume of
lease trade has fallen by 2 per cent from 1992 to 17 016 tonnes in 1997. However, there has been a large
reduction in leasing of orange roughy in line with declining allocated quota for this species. Excluding
orange roughy, the annual volume of lease trade has more than doubled from6021 tonnes in 1992 to 14 205
tonnes in 1997. On average, 10214 tonnes of quota has been leased out each year between 1992 and 1997,
equivalent to 31 per cent of total allocated quota during this period. (Hogan, Thorpe and Timcke 1999)
(table 7).




SEF Fishery Assessment Report 1999                                                                                33
Table 7 Volume of leased quota in the south east fishery

Species                         1992          1993       1994          1995       1996        1997 Average

                                     t            t           t            t           t          t           t
Total volume
Blue eye trevalla                 65            87         81            85         96         116         88
Blue grenadier                  2352          3005       2214          1534       2396        4829       2722
Blue warehou a                     –           564        577           583        753         702        636
Flathead                         515          1811       1988          2226       1926        2204       1778
Gemfish                          190           175         70            80        127         171        135
  Gemfish eastern                 85            31         23            19         12          85         42
  Gemfish western                104           144         47            61        115          86         93
Jackass morwong                  479           642        508           478        578         902        598
John dory                         54            61         75            70         69          52         63
Ling                             262           467        537           781        901         780        621
Mirror dory                      155           205        171           201        290         364        231
Ocean perch                       65           108        186           132        162         199        142
Orange roughy                  12380          9523       6522          4522       3959        3908       6802
  Orange roughy east            5379          1313       1153          1513       1410        1533       2050
  Orange roughy south           5432          7163       4638          2025       1085        1824       3694
  Orange roughy west            1568          1048        730           985       1464         551       1058
Redfish                          221           255        379           619        534         927        489
Royal red prawn                   51            59        107           137        112          79         91
School whiting                   708          1387       1246          1699       1217        1286       1257
Silver trevally                   57            92        169           212        161         160        142
Spotted warehou a                849          1360       1310          1397       1603        1434       1325

Total                          18401        19803       16142        14757       14884      18113       17016
Average b                         21           14          11           11          10         11          13
Share of total quota c %          51           58          40           36          37         47          45

Less orange roughy              6021        10279        9620        10234       10925      14205       10214
Average b                         11           99           8            9           8         10           9
Share of quota d %                33           52          33           33          34         43          31



a Blue and spotted warehou treated as a single species in 1992. b Total volume of leased quota divided by the total
number of quota lease transactions in the corresponding period. c Share of total allocated quota holdings. d Share of
total allocated quota holdings excluding orange roughy.
Source: Hogan, Thorpe and Timcke 1999; AFMA quota monitoring system.


While a number of problems in the ITQ scheme have been or are being addressed, such as those pertaining
to jurisdictional arrangements and the non inclusion of the non trawl sector, there are substantial concerns
about the effectiveness of the ITQ scheme. These include the observed systematic short fall in the fish catch
relative to the total allowable catch for most quota species and the estimated high levels of discarding for
some species in the fishery.

In each of the years in which the ITQ scheme has been operating, the actual catch has been well below the
total allowable catch for nearly all quota species. Shortfalls would be expected for some quota species in a
multispecies fishery because the catch mix is likely to vary from relative total allowable catches and
because individual operators pursue profit opportunities by highgrading and dumping certain species.



34                                                                  SEF Fishery Assessment Report 1999
However, the magnitude and number of catch shortfalls, indicate that total allowable catches may be equal
to or above open access harvest rate for at least some of the quota species.

By definition, the imposition of a total allowable catch as part of an effective ITQ arrangement in a single
species fishery represents a binding constraint on the fishery, at least in terms of landed catch. Otherwise,
fishing effort would be unconstrained and the problems associated with open access fisheries (in terms of
over capitalisation and excessive fishing) would prevail. In the case of the south east fishery, in addition to
the ITQ arrangements, a number of restrictions may represent binding constraints on fishing effort (AFMA
1996).

Over the period 1992 to 1997, there have been relatively large changes in the actual total allowable catch
for several quota species. To the extent that they vary for individual quota species, there may be increased
uncertainty about future developments in the fishery that may result in reduced investment (including
purchasing of capital equipment and quota).

Given the complex multispecies nature of the south east fishery, it is likely that a significant level of
discarding occurred prior to the introduction of ITQs, although it is not known whether the level of
discarding has increased in recent years.

Highgrading and discarding of quota fish occur because it is not feasible to monitor catches at sea. This
enforcement failure means that there are economic incentives for operators to maximise marginal ‗quota
unit‘ returns by dumping low value fish in favour of high value fish. Apart from the obvious waste, the
discarding of fish may lead to errors in total allowable catch settings.


ECONOMIC PERFORMANCE INDICATORS
Fisheries management involves a degree of separation between ownership of the fish and associated
natural resources, ownership and operation of fishing enterprises and management of the fishery as a
whole. As a result public reporting of a range of economic and biological performance measures is
necessary. Rose 1999 discusses the role of performance indicators.

For Commonwealth managed fisheries economic efficiency and cost effective management are two of the
three legislated objectives. Use of resources in a fishery is economically efficient if the net return is
maximised over time, accounting for all the value derived from the fishery and all the resources used.

The primary measure of economic performance of a commercial fishery is resource rent. Resource rent is
the long run excess of income from the fishery over fishing and management costs. A starting point for
measuring economic rent is an estimate of the apparent net return to the fisheries resources —revenue from
fishing less the full operating and capital costs of fishing (including management costs).

For a fishery in which the fish stock, fishing capital and prices are stable, the current net return to the
fisheries resource will be a good estimate of resource rent. If the fish stock or industry capital is changing
over time, a measure of the net return in one year will not be sufficient indicator of rent over the long term.
For example, if the fish stock is being fish down, current net returns include revenue from selling off part
of the fish stock that will not be available over the longer term. Similarly, if industry capital is declining
because of earlier overcapitalisation, including the full cost of capital in a calculation of net returns to the
resource will underestimate the long term returns.

Given these observations, indicators of the state of the fish stock and of industry capital, or at least
capacity, are necessary adjuncts to a measure of the net return to the fishery resource.

Rose 1999 uses information collected in ABARE‘s economic surveys to estimate net returns for the
northern prawn fishery and the offshore component of the south east fishery over the period 1990-91 to
1995-96. The measure of net return is revenue less operating costs less the full annualised cost of capital.
The results obtained by Rose for the offshore component of the south east fishery indicate the importance
of examining economic and biological indicators over an extended time. The net income measures are
unlikely to reflect the level of resource rent attainable over the long term. The period for which the


SEF Fishery Assessment Report 1999                                                                            35
measures are reported is one of fishing down the orange roughy stocks. The level of net return sustainable
over the longer term is likely to be closer to levels for the final two years than those for earlier years.

The impact the decline in the orange roughy resource had on the fishery is reflected in the estimated capital
series. Estimates of the market value of vessels bought and fitted for a high volume orange roughy fishery
have declined as the main species, and hence the prospects for the sector of the fishery have diminished.

The offshore sector of the south east fishery has been built largely on ta partial run down of the orange
roughy stock. Despite the sell off of stock, apparent net returns in the sector have not been large. Rose
(1999) concluded it was not clear that from available evidence that maintenance of a significant positive
net return from the sector is possible over the longer term.



Table 8 Net returns to the offshore component of the south east fishery (in 1998-99 dollars)
                  Net     Operating      Wages       Revenue      Replacem      Estimated         Vessel
              returns         costs                               ent capital      capital      numbers

                     $m         $M          $M             $m            $m            $m            No.

1990-91         0.98          29.47       19.45         58.60            ne         82.47             39
1991-92        11.57          20.86       11.47         51.48            ne         50.81             33
1992-93         9.76          17.38        9.84         41.40            ne         33.49             29
1993-94        17.76          19.42       10.26         49.89         12.90         43.73             29
1994-95         6.37          13.95        7.41         31.05         16.38         22.92             27
1995-96         1.11          16.21        6.72         26.72         13.85         24.09             23

Ne. Not estimated.
Source: Rose 1999.



References

ABARE 1997, Fisheries Surveys Report 1997, Canberra.

AFMA (Australian Fisheries Management Authority) 1996, Annual Report 1995-96: Protecting Our Fishing
    Future, Canberra.

Hogan, L., Thorpe, S. and Timcke, D. 1998, ‗Issues in individual transferable quotas in Commonwealth
     fisheries‘, in Outlook 98, Proceedings of the National Agricultural and Resources Outlook Conference,
     Canberra, 3—5 February 19988, vol. 1, Commodity Markets and Resource Management, ABARE,
     Canberra.

Rose 1999, ‗Australian fisheries indicators of economic performance‘, in, in Outlook 99, Proceedings of the
      National Agricultural and Resources Outlook Conference, Canberra, 17—18 March 1999, vol. 1,
      Commodity Markets and Resource Management, ABARE, Canberra.

Smith, P. B 1997, ‗Outlook for the Australian seafood industry‘, in Outlook 97, Proceedings of the National
      Agricultural and Resources Outlook Conference, Canberra, 4—6 February, vol. 1, Commodity Markets
      and Resource Management, ABARE, Canberra.




36                                                              SEF Fishery Assessment Report 1999
8.     ENVIRONMENTAL FACTORS

EFFECTS OF FISHING
Bycatch
The level of bycatch in demersal trawl fisheries is receiving increasing attention in Australia and
internationally. The term bycatch refers to the part of the catch that is caught incidentally; i.e. not targeted.
The Commonwealth has established a Bycatch Taskforce (convened by AFMA) to address this issue across
all Australian fisheries. In their draft policy statement this Taskforce adopted the bycatch definition used by
the ESD Working Group Report on Fisheries; ―The part of the catch which has no commercial value and is
returned to the sea, usually dead or dying‖. AFMA has since produced a draft ―The Commonwealth Policy
on Fisheries Bycatch‖ in March 1998.
This definition only refers to that portion of the catch that is discarded, whereas some bycatch is often
retained. In the SEF, bycatch can be categorised as that portion of the catch that is not targeted. This can be
grouped into one of the following categories:
I.    catches of quota species which are discarded for various reasons; e.g. under-sized juveniles, individual
      quota limits being reached or no quota being held, market forces (poor prices/low demand) and high
      grading (only a select portion of the catch is retained);
II.   catches of non-quota (and non-commercial) fish species which are discarded;
III. catches of species other than fish (marine wildlife) such as marine mammals, or benthos such as corals
     and sponges, which have no commercial value or are protected;
IV. catches of quota species which were not targeted but are retained (some quota species, such as John
    dory and ocean perch, are largely taken as bycatch);
V.    catches of non-quota species which were not targeted, but have commercial value and are retained.
In a multi-species fishery such as the SEF, making a distinction between targeted and non-targeted catch is
probably of questionable value, as a fisher‘s targeting practices may change within a single trip. Many non-
quota species are regularly targeted. In assessing the impact of fishing on a species, total fishing mortality
whether retained or discarded, targeted or not targeted, is the important factor. Obviously, to improve the
efficiency of fishing operations and reduce unnecessary impacts on all species, it is desirable to reduce
discarding. Gear selectivity studies are urgently needed for the SEF, particularly to reduce the catch of
juveniles of some quota species. Nevertheless, as markets develop, more species are being retained. FRDC
funded a Workshop in July 1998, to examine ways of reducing discards in the SEF.
Data on retained bycatch from commercial trawl vessels are available from the SEF1 logbook database,
although the nominated target species is often not recorded. The current Integrated Scientific Monitoring
Program (ISMP) continues to employ onboard observers who record both retained and discarded catch of
quota and non-quota species. NSW also used the same methodology to conduct a separate (but linked to
the SMP) bycatch study over the period 1993 to 1995 (Liggins 1996). SMP/ISMP data collection continued
in 1996 and 1997. These programs are the source of the discard information for the trawl sector provided in
Chapter 1. Annual discard rates for NSW (Eastern Zones A and B), the Western Zone and East Victorian
Danish Seine are between 40 and 50 per cent by weight of the total catch. Off NSW, about 30 per cent by
weight of the catch of quota species is also discarded. Annual discarding rates off western Tasmania are
lower, with discards ranging from 10 to 30 per cent of the total catch weight. SMP/ISMP data from 1993 to
1997 recorded over (some species were ―lumped‖) 264 fish species as being caught by SEF trawlers, with
138 species being retained on a regular or irregular basis. The trophic implications of bycatch and
discarding practices within the SEF are poorly understood.
The ISMP has not yet been extended to the non-trawl sector of the SEF. However, catch data suggest that
most of the non-target species caught are retained. Hook and line and mesh-net fishing practices are
generally much more selective than trawling.
Habitat changes
The trawl fishery originally began on the relatively flat, soft bottom substrates of the continental shelf off
NSW. Trawl grounds were developed by trial and error, with rocky, unfishable areas being gradually
outlined and avoided. However, developments in fishing gear technology over the past 10-15 years,
particularly echo-sounders and navigational aids such as GPS and plotters, have made trawling increasingly
possible in previously unfishable areas, usually abutting established grounds. The substrates of these areas


SEF Fishery Assessment Report 1999                                                                            37
largely consist of rocky, but relatively flat, reefs or boulders. The impact of trawling on these and other
SEF habitats is poorly understood. Concerns about habitat damage and consequent loss of species diversity
and productivity have been expressed by non-trawl fishers, as well as scientific groups and the general
public. There are currently no management regulations governing the size of bottom gear such as chains
and bobbins used by SEF trawlers, nor are there any restrictions on engine horsepower since the withdrawal
of the ―unitisation‖ input control when ITQ management commenced. The practice of establishing ―no-
fishing‖ exclusion areas, or refugia, within a fishery has been shown to be a useful management tool for
some overseas demersal fisheries. Such refugia have boosted recruitment to the overall fishery. However, if
refugia are to be considered as a management option for the SEF, preliminary GIS analysis is needed to
map which areas have, or have not, been trawled. BRS is currently undertaking GIS mapping of the SEF
and preliminary results suggest that <30 per cent of the total shelf/upper slope area within the SEF is
trawled.
Within the SEF, what constitutes important (or ―critical‖) benthic habitat for biodiversity and fish
production purposes is poorly understood. CSIRO are writing-up a study of the SEF ecosystem for which
one of the goals is to determine the importance of different habitat types for refuge and the provision of
food. An adequate understanding of the comparative importance of the major habitat types within the SEF
will probably require further research. Environmental factors other than physical habitat type (e.g. seasonal
changes in water masses) also have to be considered.
In August 1995 a Memorandum of Understanding (MOU) between AFMA and the then Australian Nature
Conservation Agency (ANCA), now Environment Australia (EA), came into effect. The MOU provides for
voluntary exclusion of an area known as the Southern Tasmanian Seamounts from bottom trawling for up to
three years. The area under temporary protection contains a significant number of seamounts which have
been lightly fished or have never been fished and therefore represent examples of relatively undisturbed
habitats suitable for scientific assessment. A research project being conducted by the CSIRO and jointly
funded by ANCA and the FRDC commenced in January 1997. The objectives of the research are to identify
the fauna inhabiting the seamounts ecosystem, assess the nature conservation significance of the area and,
where possible, assess the significance of the area in relation to similar seamount ecosystems elsewhere in
Australia and internationally. Following the release of the final report, EA are engaged in consultation
about a possible Marine Protected Area in the region. As a consequence, EA and AFMA have decided to
extend the MOU period by a further 12 months.
Fishing debris
The SEF fleet produces debris, largely of pieces of fishing gear (lost or discarded trawl nets, gillnets, traps,
or hooks and/or line) which may either entangle seals and birds, continue to ―ghost‖ fish or litter foreshores.
A study from 1989 to 1993 in the waters of Bass Strait and southern Tasmania by Tasmanian Parks and
Wildlife Service found that 1.5-2 per cent of Australian seal populations became entangled by fishing
debris. Trawl nets contributed the highest amount of neck collar material. It should be noted that these
years encompassed the ―boom‖ period for the orange roughy fishery during which time many trawl nets
were lost or burst.
In June 1995, SETMAC and SETFIA endorsed the SEF (Trawl) Industry Code of Conduct for Responsible
Fishing. It contains provisions covering international law (MARPOL) requirements regarding the disposal
of nets and plastics at sea, in acknowledgment of the need to reduce such debris. In August 1999 the South
East Non Trawl Association (SENTA) and the Southern Shark Industry Council (SSIC) will be jointly
releasing a Code of Conduct for Responsible Fishing for fishers in both sectors.
Endangered Species Legislation
The Commonwealth Endangered Species Protection Act 1992, provides for the listing of native fauna and
flora or ecological communities as endangered or vulnerable and also allows for the listing of key
threatening processes. Listing requires the development of Recovery Plans for endangered species or
Threat Abatement Plans for key threatening processes. In 1994 a public nomination was received for the
listing of gemfish as an endangered species. Another nomination was received for the eastern gemfish stock
in 1995 and one for orange roughy in 1996. After assessment of these nominations, the Commonwealth
Minister for Environment Sport and Territories decided not to list these species or stocks as endangered.
Study of the SEF ecosystem
A three-year, FRDC funded study by CSIRO to describe features of the SEF ecosystem is currently being
written-up. The study incorporated a major field program, with direct involvement of the fishing industry,
on the continental shelf from Wilson‘s Promontory to Bermagui in depths from 25 to 250 metres. The study
should provide some of the information necessary to model the habitat dependence and gear susceptibility


38                                                               SEF Fishery Assessment Report 1999
of individual commercial species and determine the ecological processes that sustain them. A series of
hierarchical models will be developed to examine the relationship between different methods of
commercial fishing on SEF fish populations and the range of habitat types, especially reef areas, occupied
by those populations. The study investigated the feeding interactions of fish species on and off reefs with
the goal of determining the importance of different habitat types in the provision of food and for refuge.
Areas and habitat types previously unstudied by fisheries researchers (hard ground) were surveyed in
addition to areas for which there is existing information.
Fishery interactions with marine wildlife
In early 1996, ANCA was approached by Tasmanian Parks and Wildlife Service to examine the
interactions between the dropline fishery off Tasmania and seals. Some dropline operators were concerned
that seal numbers are growing, resulting in increased fish losses from their fishing gear. A study by the
Tasmanian Parks and Wildlife Service is under way to assess the level of interaction and options for
mitigating any interactions. SMP/ISMP data show that the bycatch of seals by trawl gear in the SEF is of a
low order.
Sea dumping of industrial waste
In becoming a signatory to the London Dumping Convention, Australia made a commitment to address
marine pollution. Dumping of industrial waste was an important issue, particularly the current practice of
dumping jarosite in SEF waters. This is the only industrial waste dumped at sea under an Australian permit.
The Commonwealth government has announced that this dumping will cease by the end of 1997, thereby
giving the industry time to make alternative disposal arrangements or practices.


9.     MANAGEMENT IMPLICATIONS

STOCK ASSESSMENT
Most current stock assessments in the SEF rely primarily on analysis of catch and effort data (including
information on discarded catch from the ISMP) combined with some information on age and length
composition of the catch and limited biological information. More comprehensive modelling and analysis
has been carried out for orange roughy, eastern gemfish and blue grenadier, for which better information is
available. Models for blue warehou and redfish are also being developed. Orange roughy and blue
grenadier assessments also draw heavily on fishery independent data in the form of biomass estimates from
acoustic and egg surveys. The main aim of the SEF Strategic Research Plan, 1995-2000 is to collect
sufficient data to enable more sophisticated modelling of most of the remaining quota species.
AFMA has set biological reference points for orange roughy and eastern gemfish and is aiming to do the
same for all quota species. As an interim measure, while the Strategic Research Plan is pursued, AFMA has
set performance criteria based on, among other things, trends in catch per unit effort (CPUE). The catch
rate criterion seeks to maintain CPUE above its lowest annual average level from 1986 to 1994. In using
this criterion, AFMA recognised that there were a number of factors other than stock abundance that could
affect catch rates. Nevertheless, because many of those factors (such as improved technology) should
increase rather than decrease catch rates, a decline in catch rate below a target level acts as a useful trigger
to more closely examine the status of a stock in question. In the 1998 assessment, five species did not meet
their catch rate criterion. The mean annual unstandardised catch rates derived from logbook data for the
1997 fishing year for jackass morwong, John dory, mirror dory, school whiting and spotted warehou were
lower than the criterion.
In addition to triggering an increased focus on these particular species, this situation raises some general
issues regarding the specification of criteria in terms of catch per unit effort. The AFMA performance
criteria do not specify how catch per unit effort is to be determined. SEFAG has attempted to standardise
catch rates, but no satisfactory method has so far been developed. Therefore SEFAG is mainly using the
unstandardised catch rates calculated from logbook data for only those shots in which the species
concerned was recorded. It can be argued, particularly for aggregating species, that this unstandardised
catch rate is relatively insensitive to changes in stock abundance and catch rates should include shots that
had the potential to catch that species (appropriate time, location, depth) but did not. For species with
variable discard rates, catch rates should be based on total catch, not landed catch. Whereas there are
methods for standardising catch rates so that they more closely reflect stock abundance, rather than trends
in other factors such as changes in fishing practice, these methods need to be tailored to individual species
and circumstances. It is important, particularly for the species that have failed AFMA‘s performance
criterion, that these issues are resolved in the near future. For example, it is becoming apparent that


SEF Fishery Assessment Report 1999                                                                           39
catch/effort data from ―scratch‖ nets should be analysed independently from those from high-lift nets.
Many industry members are currently very sceptical about the use of catch rates in assessments, because of
the changes in fishing practices that have followed the introduction of ITQ management. The fact that
spotted warehou (a 1997 trigger species) is currently acknowledged by SEFAG and industry to be
comparatively abundant in the SEF, to the extent that its TAC has been increased, adds to such scepticism.
SEFAG flagged the need to evaluate the cost of continuing attempts to standardise catch rates against the
cost of initiating and maintaining fishery-independent abundance indices.
Stock assessments and evaluations of future management strategies are relatively well developed for orange
roughy. This allowed more specific objectives and performance criteria to be set. There was an agreed
model for orange roughy and a TAC reduction strategy was adopted by industry and management. The
reduction strategy meant that there was an agreed TAC scenario for the eastern and southern management
zones until 1998, but TACs are still considered annually, taking new data into account. The approach in
orange roughy enabled a more formal assessment of risk in adopting a particular management strategy,
taking into account the scientific uncertainties in the assessment. This situation was achieved because more
resources were assigned to research and assessment of orange roughy compared to other species. However,
this situation has changed, with there being comparatively few resources directed towards orange roughy
assessment in 1996/98. Although an Assessment Group was formed in 1997/98, dispute by industry over
the representation afforded by the 1996 St Helens acoustic survey and catch rates has impeded recent
assessment of this species. A high priority should be given to conducting a survey of St Helens Hill and
associated grounds in the 1999 winter, and to producing 1999 assessments for other SEF roughy fisheries.
Stock assessments and evaluations of future management strategies are also well developed for eastern
gemfish, being greatly assisted by the formation of a separate Eastern Gemfish Assessment Group in 1996.
A further three individual Assessment Groups were established in 1997 for blue warehou, blue grenadier
and redfish. The formation of these groups has greatly improved the quality of assessments for these
species and models have been, or are being, developed . However, for most other species, resources for
research and stock assessment are limited and do not provide for any individual or organisation to maintain
a continuing interest and level of expertise in a particular stock. Stock assessment in the SEF is likely to
continue to be a difficult balancing act between the resources available for appropriately assessing a species
and the adequacy of the assessment. Low priority species inevitably receive comparatively little attention.
With a ―global‖ Commonwealth trawl and non-trawl ITQ system for blue eye trevalla, blue warehou and
ling now being in place, a major priority of the 1998/99 workshops planned for these species is to ascertain
if data availability justifies individual Assessment Groups being established in 1999/00.

FISHING EFFORT
The 1994 to 1997 Fishery Assessment Reports noted that effort was increasing in the fishery while catch
was decreasing. The 1997 effort total in terms of hours of bottom-time (101243 hrs) was the highest since
logbook records began in late 1985 and represents a 34 per cent increase on the 1991 total (75785 hrs). It is
highly probable that considerable under-reporting occurred in 1992 and the effort total recorded for that
year is less than the true total. However, total SEF effort increased by 7.3 per cent from 1993 to 1994, 10.8
per cent from 1994 to 1995, 7.5 per cent from 1995 to 1996 and 7.6 per cent from 1996 to 1997. This is a
consistent and worrying trend, particularly when considering that many vessels have increased their
capacity and engine horsepower since the ―unitisation‖ input control was abandoned in 1992 and have also
installed GPS and plotters. The actual (i.e. real) increase in fishing effort is clearly much greater, but is
difficult to quantify without assessing the performances of individual vessels in the fleet separately.
NSW industry have rightly pointed out that some of this effort increase is attributable to a shift away from
target fishing to more speculative, mixed-species trawling, This has occurred to avoid eastern gemfish in
winter, to ensure their allocations of other quota species do not run out before the end of the year and to
avoid ―flooding‖ the market with individual species. However, this is only part of the problem. Much of the
effort increase has resulted from the downturn in the orange roughy fishery and the shift to ―market‖ fishing
in shallower waters by some of the deepwater fleet. This shift is particularly pronounced to the west of Bass
Strait, where recorded effort in the western statistical zone (Figure 3) increased by 74 per cent from 1994 to
1997. Effort in Eastern Sector B has also risen by 50 per cent over this period. Furthermore, it could also
be claimed that the development of the South Tasman Rise orange roughy fishery, which lies largely
outside the EEZ, diverted some effort away from the SEF in 1997.




40                                                              SEF Fishery Assessment Report 1999
The annual total landed weight of quota species, other than orange roughy, has remained comparatively
stable from 1991 to 1997 (again, allowing for under-reporting in 1992). Thus, because of increasing effort,
the overall SEF catch rate continues to decline. If effort continues to increase, it is probable that the catch
rates of several individual quota species will decline and consequently trigger AFMA‘s catch rate
performance criterion. For most quota species, the current stock status is unclear. However, for some
species, it is reasonable to assume that the increase in fishing effort is impacting on the stock. A high
management priority should be given to avoiding further increase in trawl effort within the SEF.
Shot-by-shot catch and effort data for the non-trawl sector are few and an ongoing priority should be given
to maintaining good data quality in the recently introduced non-trawl logbook.
For those species for which a ―global‖ TAC has been introduced, the implications of transferring quota
(hence, effort) between the trawl and the non-trawl sectors need to be considered. The 1998 blue warehou
assessment noted the differences in estimated fishing mortalities between sectors.

INDIVIDUAL TRANSFERABLE QUOTAS
With the exception of eastern zone orange roughy, ling and blue and spotted warehou, the 1996 recorded
catch totals of quota species were no more than 80 per cent of their TACs. For eight species, less than 50
per cent of the TAC was landed. For several species, catches have never exceeded 50 per cent of the TAC
since ITQ management was introduced. There are a variety of possible explanations for this situation,
ranging from biological reasons such as a decline in stock abundance (i.e. the TAC is too high), to
management/trading issues with allocation and transferability of quotas (i.e. quota is ―locked-up‖ and not
being used to fish), to various marketing issues. Analysis of quota holdings and trading is needed to
determine whether there are impediments to efficient use of the ITQ system and how they might be
overcome. (An ABARE study to address this issue is proceeding.)
Many operators have stated that for quota species with a comparatively low market value, the lease prices
result in such a low profit margin that fishers often discard rather than lease-in the quota required. If
discarding (for various reasons) is taken into account, the catch totals of species such as ocean perch
regularly exceed the TAC (see below).
SEFAG noted that port surveys revealed a widespread industry perception that ―if a TAC is significantly
under-caught, it will inevitably be reduced in the future‖. The Group placed on record; that the level of
catch against a TAC in a given year has little influence on the SEFAG stock assessment process.

DISCARD RATES
In the 1995 Fishery Assessment Report, SEFAG identified the need for a review of trawl gear used in the
SEF with the primary aim of reducing unwanted bycatch, particularly of small or juvenile commercial fish
species. This need has been reinforced by the results from the SMP/ISMP and the complementary NSW
bycatch study. The discarding of about 30 per cent by weight of the catch of quota species off NSW is of
serious concern. Since small fish tend to be discarded more frequently, the discard rate in terms of numbers
is significantly higher. Discard rates off NSW (Liggins 1997) are highest for redfish (annually, 24-56 per
cent by weight during 1993 to 1996), blue warehou (1-23 per cent), gemfish (8-82 per cent*), mirror dory
(15-60 per cent), tiger flathead (12-17 per cent) and ocean perch (18-86 per cent), especially the inshore
ocean perch species (83-86 per cent). (*largely because of the zero TAC over this period). More recent
(1996/97) data show that redfish discarding has fallen to <10 per cent off NSW, but blue grenadier
discarding across the fishery is now very high, peaking at 15 per cent in the Western Zone. Anecdotal
reports suggest that the discarding of eastern gemfish by the non-trawl sector has also been significant.
Discarding of fish, both commercial and non-commercial, has negative impacts; both on the stocks
concerned and the fisher, as fishing effort has been expended for no economic return. Methods of
improving the selectivity of fishing are urgently needed. FRDC has established a Bycatch Committee to
examine this issue across all Australian fisheries and a workshop to examine this issue in the SEF and
facilitate research to address the problem was held on 30-31 July 1998.
Discard rates must be taken into account in stock assessments since it is the total mortality of fish, not just
the retained catch, that should be included in analyses. The continuation of on-board monitoring of the
trawl sector is essential for this purpose, and such monitoring should be extended to the non-trawl sector.
Quantitative information of bycatch and discard rates is also essential to assess the performance of catch
limits such as TACs or trip-limits as a management tool.




SEF Fishery Assessment Report 1999                                                                            41
10.    RESEARCH NEEDS
Certain basic data requirements are fundamental to the management of the SEF. They include fishery
dependent data listed in Appendix 3 that are needed on a regular basis to support the stock assessment
planned for each quota species and economic information necessary to provide managers and the
community with an assessment of the economic performance of the fishery. These requirements apply to
both the trawl and non-trawl sector. They are not considered further in this section. ―Research Needs‖ refer
to specific ―one-off‖ research projects with a recognisable end point that would improve stock assessment
and assist management.
Research needs identified in the 1997 Fishery Assessment Report are listed in Box 1 together with a
statement of their present status. Research needs for 1998 repeat some of those needs from 1997 that have
not yet been filled and add new projects identified during the 1997/98 SEFAG process. As part of the 1998
assessment and research process, SEFAG and the SETMAC Research Sub-Committee revised 5-year
research plans for each of the 16 quota species. Plans for general and economic research were also drafted
and will be developed further during the SEFAG planning meeting in late 1998.
The individual FAGs were responsible for developing research needs/plans for their particular species and
SEFAG also flagged particular specific needs. Species specific needs are provided in the Stock Assessment
Reports and Species Summaries
The following general SEF and key species research needs were identified by SEFAG and the SETMAC
Research Sub-Committee. These are not listed in order of priority.

General SEF Research

1. Basic biology of SEF quota species.
2. Costs and benefits of different data inputs, including environmental factors, in stock assessment of SEF
   quota species.
3. Application of multi-species assessment methodology in the SEF.
4. Spatial management options evaluation in the SEF.
5. More detailed analysis of SEF logbook data, especially catch per unit effort series and spatial
   dynamics.
6. Biological and economic implications of alternative bycatch and discarding policy options for the SEF.
7. Changes in SEF fish communities.
8. Identification of critical fish habitats in the SEF.
9. Impact of seismic surveys on fish and marine environment in the SEF.
10. A review of the literature related to the use of economic efficiency indicators in fisheries, and other
    related industries if literature is scarce (eg. pollution control). Examination of the utility of such
    indicators in fisheries managed under input and/or output controls.
11. An analysis of the benefits of using integrated bioeconomic modelling in harvest strategy evaluation by
    way of case studying one or more SEF quota species.
12. Biological and economic implications of shifts of fishing effort between the trawl and non-trawl sectors
    of the SEF.
13. Identification of, and framework development for analysing, the ―spill-over‖ effects of fishing methods
    in the SEF trawl and non-trawl sectors to: operators in each sector in the SEF; operators outside the
    SEF; and others outside fisheries.
14. Analysis of seasonal variation in product quality of SEF quota species.
15. Pilot study of on-board monitoring of SEF non-trawl vessels.
16. Workshop on the climatic and oceanographic influences on southern Australian fisheries.
17. Revision of age composition of jackass morwong using age estimates from sectioned otoliths.



42                                                               SEF Fishery Assessment Report 1999
18. Synthesis of existing data with limited sampling to model predation and potential competition between
    southeastern Australian fisheries.
19. The impact of climate variability on the fisheries oceanographic environment of the eastern and western
    Australian EEZ.
20. Documented catch series for SEF quota species.

Key Species Research

1. Ageing of otoliths to improve understanding of biology for: mirror dory, eastern school whiting, ocean
   perch and john dory.
2. Spawning and reproductive characteristics of blue grenadier.
3. Fishery independent surveys for blue grenadier and blue warehou, following an evaluation of whether
   egg, acoustic, or trawl surveys would be most appropriate.
4. Harvest strategy evaluation for blue grenadier, blue warehou and redfish.
5. Desktop study of production parameters for species biologically similar to blue warehou.
6. Assess the value of industry surveys for long term monitoring of relative abundance of eastern gemfish,
   including winter trawl surveys for eastern gemfish.
7. Continued size/age monitoring of eastern gemfish spawning run.
8. Further analysis of catch rate data for eastern gemfish.
9. Extension of the stock reduction and risk assessment model for orange roughy to include changes in age
   structure and explicit spatial stock structure.
10. Key biological information for orange roughy from the Cascade Plateau and South Tasman Rise.
11. A bibliographic compilation of existing research relevant to redfish stock assessment.
12. Acoustic survey to estimate redfish biomass.




SEF Fishery Assessment Report 1999                                                                       43
Box 1. Research needs (in order of priority) identified in the 1997 Fishery Assessment Report and their
present status.

1. Identification and documentation of data sources. An application will again be submitted by BRS to
   carry out this work in 1999. The previous application was supported but anticipated funding was
   diverted elsewhere.

2. Documentation and analysis of fishery information. Parts of this project, such as GIS mapping of
   catches and effort are proceeding. An application will be made for FRDC funding for 1999/00 to enable
   more detailed spatial/temporal analysis and integration of major industry-driven and environment-
   driven factors.

3. Socio-economic analysis of ITQ performance. ABARE are conducting this study, which is nearing
   completion.

4. Environmental influences on fish stocks. This FRDC-funded study conducted interviews with
   operators across the fishery and has been completed. Results will be incorporated and developed in the
   proposal outlined in 2 above.

5. Techniques to evaluate management and harvesting strategies. Work by CSIRO has continued with
   eastern gemfish and orange roughy. The funding application to extend this to other SEF species was
   successful and this study is under way.

6. Methods to reduce discarding of quota species. No work has been funded thus far. The co-operative
   proposal by AMC, MAFRI and FRI submitted for FRDC funding led to a workshop in July 1998 to
   further develop a program of gear selectivity research in close consultation with industry. Work should
   commence in 1999.

7. Fishery independent data collection. The RV Kapala survey final FRDC report was completed in
   December 1997. Targeted research on the feasibility of using commercial vessels for collecting fishery
   independent data on a routine basis has still not commenced.




11.    CONSISTENCY WITH FISHERIES ECOSYSTEM MANAGEMENT
Fisheries Ecosystem Management (FEM) is a framework for incorporating the principles and policies of
ecologically sustainable development into fisheries management. It is part of the National Strategy for
Ecologically Sustainable Development (1992). The Standing Committee on Fisheries (now the Standing
Committee on Fisheries and Aquaculture) developed a FEM assessment process in 1992. The format of
AFMA‘s Fishery Assessment Reports, including this one, is based on the Committee‘s proforma that is
reproduced in Chesson (1995).
There are several significant developments occurring in the SEF that are consistent with the principles of
FEM. They include inclusion of the non-trawl sector under a common management umbrella and Offshore
Constitutional Settlement agreements with the States. These developments are discussed in more detail
below.

CROSS SECTORAL ISSUES AND IMPACTS
The need to consider all impacts on a stock, not just those imposed by the trawl sector, has been
emphasised in previous assessment reports. The non-trawl sector takes significant quantities of some quota
species, yet data from this sector are limited. The SEF Non Trawl Consultative Committee (SEFNTCC)
was formed in 1994 as an initial step towards an integrated SEF. The SEFNTCC was replaced on 1 July
1998 by the South East Non-Trawl Management Advisory Committee (SENTMAC). A Commonwealth
non-trawl specific logbook was introduced in January 1997 and an ITQ system that complements the trawl
ITQ system for blue eye trevalla, blue warehou and ling was introduced on 1 January 1998. It has been

44                                                            SEF Fishery Assessment Report 1999
agreed by the newly formed SENTMAC, that complementary ITQ management will be extended to all SEF
quota species.

STRUCTURED MANAGEMENT MECHANISMS
Offshore Constitutional Settlements (OCS) rationalising management of stocks that span Commonwealth
and State waters have been agreed to in principle by the Commonwealth, Victoria, Tasmania and South
Australia. Negotiations are still underway with New South Wales. However, NSW has introduced trawl trip
limits for SEF quota species in State waters. OCS agreements and State trip limits have now largely
eliminated spatial misreporting of trawl catch to avoid Commonwealth quota restrictions. Management
arrangements for the non-trawl sector off NSW need resolving.

USER AND PUBLIC AWARENESS / EDUCATION
FEM encourages a broader view of fisheries management encompassing the interests of stakeholders
beyond those directly involved with commercial fishing. This has been recognised with the extension of
SETMAC to include members representing conservation interests.
Areas of public concern include:
Overfishing of some stocks. Eastern gemfish was nominated for listing under The Endangered Species
Protection Act in 1994. Although this nomination was unsuccessful, it demonstrates the increase in public
scrutiny of the fishing industry.

Habitat damage by trawling. A shift towards increasing usage of heavier bottom gear, etc., and targeting
previously inaccessible areas with the assistance of satellite navigation aids, has led to growing concern
about habitat damage. This concern is coming both from within industry (ie. the non-trawl sector), scientific
groups and the general public. In 1995, industry agreed to the establishment of a Interim Protected Area
encompassing a group of deep sea-mounts off southern Tasmania to protect the benthic communities.
However, initial GIS mapping of fishing effort suggests that only <30 per cent of the overall SEF
shelf/upper slope area is trawled, although the proportion in the Eastern Sectors is higher.
Bycatch. Environmental groups have been and are actively lobbying for the reduction of bycatch by all
commercial fishing sectors. Whereas oceanic drift netting and long-lining have been major targets, trawling
is coming under increasing scrutiny. A draft Commonwealth Bycatch Policy has been developed and a SEF
Bycatch Action Plan will be drafted under this policy for public comment.
Fishing debris. SETMAC has endorsed the Industry Code of Conduct for Responsible Fishing, which
includes provisions regarding disposal of nets and plastics at sea, and in August 1999 the South East Non
Trawl Association (SENTA) and the Southern Shark Industry Council (SSIC) will be jointly releasing a
Code of Conduct for Responsible Fishing for fishers in both sectors.



DATA AND RESEARCH
The amount and quality of data available for the SEF are generally inadequate for the assessments needed
to specify total allowable catches and are heavily reliant upon fishery-dependent information. However, this
situation is improving. An integrated scientific monitoring program (ISMP) encompassing on-board, port
and market-based data collection across the trawl sector (and soon the non-trawl sector) has replaced the
SMP. SEFAG and the individual FAGs have contributed to this process by systematically identifying stock
assessment techniques appropriate to each species and the associated data requirements. In 1997, SEFAG
also facilitated the review of 5-year strategic research plans for each quota species and assisted in reviewing
the SETMAC Research Sub-Committee‘s 5-year strategic plan.


12. REFERENCES

ABARE (1995) Fisheries Surveys Report 1995, Canberra.
ABARE (1997) Australian Commodities, Forecasts and Issues, vol. 4, no. 2.
ABARE (1997) Fisheries Surveys Report 1997, Canberra.


SEF Fishery Assessment Report 1999                                                                          45
AFMA (Australian Fisheries Management Authority) 1996, Annual Report 1995-96: Protecting Our
Fishing Future, Canberra.
Chesson, J. (ed) (1996) The South East Fishery 1995, Fishery Assessment Report, compiled by the South
East Fishery Assessment Group, AFMA, Canberra.
Chesson, J. (ed) (1997) The South East Fishery 1996, Fishery Assessment Report, compiled by the South
East Fishery Assessment Group, AFMA, Canberra.
Daley, R.K., Last,P.R., Yeardsley, G.K. and Ward, R.D. (1997) South East Fishery Quota Species: an
identification guide, CSIRO Div. Mar. Res., Hobart.
Klaer, N. and Tilzey, R.D.J. (1994) The multi-species structure of the fishery, in Tilzey, R.D.J. (ed) (1994)
The South East Fishery: A scientific review with particular reference to quota management, AGPS,
Canberra, 72-94.
Hogan, L., Thorpe, S. and Timcke, D. (1998) ―Issues in individual transferable quotas in Commonwealth
fisheries‖, in Outlook 98, Proceedings of the National Agricultural and Resources Outlook Conference,
Canberra, 3-5 February 1988, vol. 1, Commodity Markets and Resource Management, ABARE,
Canberra.
Liggins, G.W. (1996) The interaction between fish trawling in NSW and other commercial and recreational
fisheries, Final Report to FR&DC, Project 92/79.
Liggins, G.W. (1997) Integrated Scientific Monitoring Program for the SEF in 1996 (NSW component),
Report to AFMA, May.
Powell, Jensen and Horwood (1989) The effects of policy change on south east trawl fishing communities,
Report to the steering committee on long tern management of the south east trawl fishery, University of
New England, December.
Smith, P. B (1994) ―Outlook for Australian fisheries products‖, in Outlook 94, Proceedings of the twenty
fourth Outlook Conference, Canberra, January, 209-17.
Smith, P. B (1997) ―Outlook for the Australian seafood industry‖, in Outlook 97, Proceedings of the
National Agricultural and Resources Outlook Conference, Canberra, 4-6 February, vol. 1, Commodity
Markets and Resource Management, ABARE, Canberra.
Tilzey, R.D.J. (ed) (1994) The South East Fishery: A scientific review with particular reference to quota
management, AGPS, Canberra.


13.    FISHERY ASSESSMENT GROUP WORK PLAN, 1998-99

OBJECTIVES
To provide an annual assessment on the status of the SEF and its component stocks in the context of stated
management objectives.

STRATEGY
Having produced a 1994 Stock Assessment Report for each quota species, SEFAG is now taking a more
strategic approach and concentrating each year on particular species according to AFMA and SETMAC
priorities and the availability of new information. The timetable for assessments is given in Table 1. This
timetable will be reviewed and revised as needed. As separate Assessment Groups are now in place for blue
grenadier, blue warehou, eastern gemfish, orange roughy and redfish, stock assessments for these species
will be produced on a regular basis, at least during the life of these groups. It is anticipated that a 1998
Stock Assessment Report will also be produced for blue-eye trevalla. Whereas jackass morwong, John and
mirror dory again triggered AFMA‘s catch rate performance criterion, it is uncertain if sufficient new
information will be available to warrant another full stock assessment. The remaining quota species will be
reviewed briefly and their Species Summaries updated.

Because of the move to ―global‖ quota and the increasing importance of blue eye trevalla and ling, an
application for funding to hold Assessment Workshops for these species in 1998/99 was made. This proved
successful. Funding has also been obtained for a School Whiting Workshop, following concern about the
current status of this species.



46                                                              SEF Fishery Assessment Report 1999
A planning meeting will be held in late 1998 to determine details of consultancies, workshops and other
arrangements for research (modelling etc.) and for the production of Stock Assessment Reports, Species
Summaries and reports on other topics. The reports and summaries will be reviewed at the annual SEFAG
meeting in late June/early July 1999. Assessments of the stocks of quota species in the SEF will include
data from all available sources (including trawl and non-trawl fisheries).

Table 1. Plan for Species Assessment Reports.

       1995                    1996                  1997                  1998                  1999
blue grenadier          blue warehou          blue grenadier        blue grenadier        blue grenadier

blue warehou            eastern gemfish       blue warehou          blue warehou          blue warehou

blue eye trevalla       flathead              eastern gemfish       eastern gemfish       eastern gemfish
eastern gemfish         John dory             blue eye trevalla     orange roughy         orange roughy
jackass morwong         mirror dory           jackass morwong       redfish               redfish
king dory               ocean perch           mirror dory           blue eye trevalla     ling
ling                    orange roughy         orange roughy         John dory             blue eye trevalla

orange roughy           oreos                 redfish               silver trevally       school whiting

redfish                                       western gemfish

Note: The final production of the Species Assessment Reports takes place at the beginning of the financial
      year. The budget cycle covers the final production of one year‘s reports and the research and
      preparation of the next year‘s reports. For example, the 1997/98 budget covers final production of
      the 1997 reports and the research and preparation of the 1998 reports.

MEMBERSHIP
Chairperson
4 Government scientific members (one each from NSW, Victoria, Tasmania and CSIRO or BRS)
1 Industry scientific member
4 Industry members (2 each from the trawl and non-trawl sectors)
AFMA member
ABARE Economist
AFMA Consultant
AFMA Secretary
Other persons may be co-opted onto the group to participate in discussions and/or contracted to write
individual species assessments as required.

TERMS OF REFERENCE
The following terms of reference for the SEFAG were endorsed by SETMAC54 on 10-11 July, 1996.
1. To provide a scientific and economic assessment of the status of demersal scalefish resources in south
   eastern Australia:
           based on information from all participants (including scientists, economists, managers and
            industry) in the assessment process;
           concentrating on Commonwealth commercial species currently under Commonwealth TAC/ITQ
            management and other key species;
           to provide to AFMA, SETMAC AND SEFNTCC and other relevant agencies comprehensive
            fishery assessments on TAC/ITQ species, and other key species as needed;
           to provide summaries on the status of each TAC/ITQ stock and other key species to all user
            groups; and
           to make the annual ―South East Fishery - Fishery Assessment Report‖ available to AFMA,
            SETMAC, SEFNTCC, SEF operators, State governments, EPA and others with an interest in the
            fishery.



SEF Fishery Assessment Report 1999                                                                          47
     2. To provide summaries on the status of each TAC/ITQ species for consideration by the TAC Sub-
        committee of SETMAC and SEFNTCC as part of the TAC setting process for the SEF.
     3. To provide advice to the Research Sub-committee of SETMAC and SEFNTCC on:
         research needs and priorities for each species in relation to stock assessment, ecosystem and
          economic research issues; and
         matters related to the collection and analysis of information needed for the fishery assessment
          process.
     4. To provide for comment from, and consider the views of, relevant individuals and groups who may
        have interest in the fishery to enhance the quality of the fishery assessment process and forthcoming
        reports.

OUTPUTS
     Annual Fishery Assessment Report
     Annual Fishery Assessment
     Compendium of Species Assessment Summaries
     Economic Assessment Report
     Stock Assessment reports
     Ad hoc reports related to SEF fishery assessment

PROPOSED SCHEDULE
   Central SEFAG                     Planning meeting in December 1998 to determine details of
                                     consultancies (including identification of consultants), workshops
       and production of reports.

                                     Mid April 1999 Port meetings with industry in western Bass Strait and
                                     Tasmania.

                                     Plenary Meeting in late June - early July 1999 to review assessments,
                                     species summaries and prepare report to SETMAC TAC sub-
                                     committee. This meeting is open to all interested parties.

                                     Mid August 1999. Summary assessment report forwarded to AFMA and
                                     thence to TAC sub-committee, SETMAC.

                                     Workshops to collate/review available information for ling, blue-eye
                                     trevalla and eastern school whiting will also be held in 1998/99. Dates
                                     to be arranged.

The individual assessment groups, BGAG, BWAG, EGAG, ORAG and RAG have each budgeted to hold
2-3 meetings during 1998/99. Dates to be arranged.




48                                                              SEF Fishery Assessment Report 1999
Blue Eye Trevalla   49
SPECIES SUMMARIES
BLUE EYE TREVALLA

1.     AFMA’S MANAGEMENT OBJECTIVES, STRATEGY AND PERFORMANCE
       CRITERIA

(To be updated by AFMA)

Objectives
1.   To ensure that the blue eye trevalla resource is utilised in a manner consistent with the
     principles of ecologically sustainable development.

Immediate objective
    To ensure that the spawning biomass of blue eye trevalla does not significantly decline below its
    current (1994) level:

     —     current jurisdictional boundaries and varying approaches to management by the States and
           Commonwealth need to be reconciled if this objective is to be achievable;

     —     noting that blue eye trevalla is predominantly taken by hook and gillnet operators.

2.   To maximise the economic efficiency of the blue eye trevalla fishery.

3.   To promote the controlled utilisation of blue eye trevalla.

4.   To implement effective and efficient fisheries management on behalf of the Commonwealth.


Strategies
The above objectives will be achieved by:

1.   setting a TAC for the Commonwealth managed portion of the fishery:

     —     that maintains catches and catch rates within their range from 1985 to 1994;

     —     the TAC would currently only apply to the trawl sector of the fishery within the SEF,
           excluding the southern Remote Zone.

2.   managing all sectors of the blue eye trevalla fishery in a complementary manner and,

3.   where appropriate, applying a TAC and ITQs to the fishery for all sectors under Commonwealth
     jurisdiction.

4.   prioritising blue eye trevalla research in relation to other SEF species:

     —     the Research Sub-committee of SETMAC has proposed a low priority rating be given for
           research into this species.

5.   data collection:

     —     obtain estimates of catch, catch rates and monitor shifts in effort and changes in:

50                                                                          SEF Species Summary 1999
     ..    fishing practices;

     ..    monitoring of length distributions in commercial catches and undertake ageing as required.

6.   undertaking economic research on fishery to calculating GVP and monitoring market prices for
     blue eye trevalla.


Performance Indicators (1995 - 1996)
1.   The status of the blue eye trevalla resource relative to the objectives:

     —      that catches and catch rates remain within their range from 1985 to 1994.

2.   That all sectors of the fishery are managed in a complementary manner.

3.   The economic and financial performance of the fishery:

     —      the blue eye fishery continues to be a viable component of the SEF.

4.   The effectiveness of a research program contributing to the objectives set for the fishery,
     including:

     —      catch and effort data have been extracted and analysed to provide a basis for performance
            indicator (i);

     —      length frequency monitoring has been maintained;

     —      a total catch figure for the fishery.

5.   The actual trawl catch relative to the trawl TAC.


2.        STOCK STRUCTURE AND LIFE HISTORY

Within the AFZ, blue eye trevalla are found from NSW to WA, including Tasmania. They occur over
hard bottom on the outer continental shelf and upper slope and on offshore seamounts.

The distribution of larvae and juveniles is unknown. Juveniles are believed to be pelagic up to the
size of about 45 cm FL (when about 2 to 3 years old), and to then settle to a semi-demersal habitat.
They appear to be fully recruited to fishing at length of about 50 cm FL.


The results of genetic analyses suggest that data are not inconsistent with the hypothesis of only one
stock of blue eye trevalla in the SEF area.

Estimated ages in commercial catches range from 2-3 years at first capture for both sexes, to 42 and
39 years for females and males, respectively, with great variation in the size of fish at age.

There is some evidence that spawning of blue eye trevalla is widespread within southern Australia
and takes place on grounds near the continental slope as well as on offshore seamounts. However,
most spawning activity has been observed within the area from central NSW to north-eastern
Tasmania. Spawning occurs in summer-autumn, somewhat earlier (March-April) in Tasmania than in
NSW (April-June).


Blue Eye Trevalla                                                                                        51
Average sizes at maturity were estimated at 72 and 62 cm for females and males, respectively (based
on Tasmanian dropline catch composition), corresponding to estimated average ages of about 11-12
and 8-9 years, respectively. The fecundity of blue eye trevalla is high, females producing between
about 2 and 11 million eggs each year, depending on their size. Large blue eye trevalla become more
vulnerable to the dropline fishery when they aggregate during spawning.

Recent tagging trials made in NSW suggest that young blue eye trevalla undertake significant movements
along the continental slope after they have settled from their pelagic habitat. It is believed that older/larger
fish could be more sedentary.



3.     THE FISHERY

Blue eye trevalla are targeted by line fishers, with the majority of catches coming from the dropline
fishery off Tasmania. Blue eye trevalla are also caught in small quantities by demersal trawling,
mostly as by-catch of blue grenadier. In the late 1980s a conflict began between traditional line
fishers and trawl fishers who wanted to develop mid-water trawl fishing methods to target semi-
pelagic species such as alfonsino and blue eye trevalla. Large trawl catches of blue eye trevalla (of
about 10 t/shot) made in the late 1980s-early 1990s prompted complaints from dropliners and trawl
catches were subsequently limited by a 125 tonne TAC in 1992. In January 1998 a global TAC of
630 tonnes was implemented to cover both trawl and non-trawl catches with 530 tonnes apportioned
to the non-trawl sector and 100 tonnes to the trawl sector.


Following recent Offshore Constitutional Settlement (OCS) agreements the blue eye trevalla line
fishery within the SEF is under Commonwealth jurisdiction off Tasmania, Victoria and South
Australia but under State jurisdiction off NSW (waters up to 80 nautical miles are under State
jurisdiction). Offshore seamounts are under Commonwealth jurisdiction.


The annual gross value of recorded landings of blue eye trevalla in the SEF zone is estimated at
about A$ 2.5-3.0 million for the hook sector; the value of trawl catches was $0.4 million in 1994. (To
be updated by ABARE)

Prices on the Sydney and Melbourne markets exhibit no apparent seasonal pattern but have shown an
upwards trend over the last few years. It is the highest valued species of the sixteen quota species,
averaging $5.80/kg in 1994. Reported market prices for blue eye trevalla are not separated by fishing
method. The average price received by trawler operators (net of marketing charges) in 1994 was
estimated to be about $4.60/kg, up about 21 per cent on the 1992 average net return. (To be updated
by ABARE).

A blue eye trevalla workshop was held in April 1999 at the CSIRO, Hobart, to review available
information on this species and discuss possible approaches to quantitative stock assessment. A
report describing the outcomes of the workshop has been circulated to industry members and
scientists present at the workshop. It was recommended that a temporary working group be formed to
consolidate all information held in various state agencies.

In 1999, port meetings were organised in South Australia, west Victoria and Tasmania. Industry
attendance was good in Portland but very poor elsewhere, particularly in the case of non-trawl fishers
(this was partly attributed to the scheduling of the blue eye trevalla workshop shortly after the port


52                                                                            SEF Species Summary 1999
meeting in Hobart). The major issue discussed by industry members present at the meetings
concerned the difficulties that trawl fishers are experiencing in covering their by-catches of blue eye
trevalla. The two major causes being the reduction of the trawl TAC as a result of the apportionment
of the global TAC between the trawl and non-trawl sectors and the poor efficiency of the quota
trading market within the trawl sector. Some fishers also claimed that blue eye trevalla have been
more abundant on trawl grounds in recent years, particularly in the western Bass Strait region.


4.     PREVIOUS ASSESSMENTS


The blue eye trevalla non-trawl fishery has only been studied in detail in Tasmania and NSW using
available catch monotoring and state logbook data. Commonwealth logbooks for the non-trawl sector
were introduced in late 1997. Trawl catch and effort data have been recorded in the Commonwealth
logbooks since 1986.


The dropline fishery has mainly developed on the continental slope, but offshore seamounts off
Tasmania, NSW and Queensland are also exploited on an irregular basis. Annual non-trawl landings
(including NSW) increased steadily from less than 500t in the mid-1980s to about 750t in 1996
(Table 1) reaching a maximum of over 1000t in 1997 just before quota for the non-trawl sector were
introduced in 1998.

There have been noticeable changes in catch rate and length composition of blue eye trevalla in
Tasmanian and NSW non-trawl catches over the years. In Tasmania, catch rate at the beginning of
the fishery in the 1970s was high, at about 3 t/boat-month, and by the late 1980s it had decreased to
about 1-1.5 t/boat-month. It then increased again steadily reaching about 2-2.8 t/boat-month between
1995 and 1998, most likely reflecting an improvement in fishing technology (i.e. GPS and
monofilament). Catch rate on the NSW continental slope is generally lower than in Tasmania.

The depth distribution of blue eye trevalla appears to be size dependent (with larger fish inhabiting
deeper waters) and changes in fishing practices over the years have led to significant changes in the
size composition of dropline catches. In the early years of the fishery off Tasmania and NSW, large
fish (averaging between 70 and 80 cm FL) were caught on the deep grounds where the fishery
initially developed. As the size of fish and the catch rate declined rapidly on these grounds, fishers
progressively moved to shallower grounds, targeting semi-pelagic schools of immature and newly
settled fish (below 55 cm FL).

Today three groups of blue eye trevalla can be distinguished in Tasmanian and NSW commercial
dropline catches: new recruits (45 to 55 cm FL) which dominate catches, young adults ( 55 to 65 cm
FL) always present in catches but in low quantities, and adults (over 65 cm FL) caught seasonally
when forming spawning aggregations. The proportion of these three groups of fish in commercial
catches varies significantly with the fishing gear used, the ground/depth fished and the time of the
year (larger fish being caught during the spawning season).

Annual trawl catches of blue eye trevalla in the SEF have varied from 16 to 110 tonnes between 1986
and 1997 (Table 1). Graphic analysis of catch statistics shows no change in the spatial and depth
distribution of trawl catches and fishing effort. Catches are made throughout the SEF area (except
Bass Strait) at depths between 350 and 550 m along the continental slope (except for occasional



Blue Eye Trevalla                                                                                         53
targeted trawl shots on offshore seamounts).

By-catches of blue eye trevalla in demersal trawl shots are usually less than 100kg. However, high
catches can be made when mid-water trawl gear is used to target blue eye trevalla, as was the case
between 1988, 1991, 1994 and 1997. Some of these few large catches (ranging from 10 to 24 t) were
recorded from the Cascade Plateau with catch rates of between 1.2 and 4.0 t/hour.


5.     1999 ASSESSMENT


There is no formal (quantitative) stock assessment for blue eye trevalla in 1999.


Catch and catch composition

After the record level of 1997 non-trawl catches in the SEF area fell sharply to 381t in 1998 following
the implementation of ITQs (Table 1) and the non-trawl quota of 530t was not caught. Non-trawl
catches off NSW in 1998 are preliminarily estimated at about 120t. According to Tasmanian
dropliners, little fishing took place early in the year (the peak fishing season for blue eye trevalla)
because of the ‗wait and see‘ reaction from fishers just after ITQs were allocated, combined with poor
fishing conditions at that time (cold waters from the south which would normally occur off the
Tasmanian coast around May occured much earlier in 1998, in March).

The annual trawl catch in 1998, at 96t, was similar to previous years (Table 1). However, trawl
fishers are reporting some problems with their by-catch of blue eye trevalla. The problems appear to
be worse in the western Bass Strait area where analysis of logbook data indicates that catch rate of
blue eye trevalla (in market fishing shots) is usually higher than in other areas. Quota holdings for
blue eye trevalla are small in the trawl sector and with the decrease in the trawl TAC in 1998 (from
initially 125t to 100t under the global TAC) fishers are having difficulties finding quota to cover their
by-catches.

Fish length data recorded by officers from the ISMP and from the NSW Fisheries Research Institute
indicate that, overall, blue eye trevalla catches in the SEF are still comprised of a majority of
immature, newly settled fish. In recent years however a greater proportion of larger fish (young
adults) seems to be caught and this could result from a combination of market and management
factors.


Uncertainties


The size of the blue eye trevalla stock and its current status are still uncertain. The consequences that
the 1998 changes in the management regime will have on the structure and dynamics of the non-trawl
fishing fleet are also unknown.

Size structure of commercial catches
The factors behind the size structure of the blue eye trevalla stock are not well understood. The
vulnerability of this species to various fishing gears appears to be size dependent and probably results
from a combination of gear selectivity and gear-specific fishing patterns.




54                                                                           SEF Species Summary 1999
  Dropline catches in NSW and Tasmania have followed the same trends over time: catches of large
  fish on deep grounds (on the continental slope and on offshore seamounts) were initially high but
  decreased rapidly, and fishing then concentrated on smaller fish on shallower grounds. The increase
  in catch of young adults is of some concern for the stock as most of these fish would have been close
  to reaching sexual maturity and to spawning for the first time. Catching them could further reduce the
  stock of spawners, possibly already reduced by fishing on deep grounds in the 1980s.

  Continental slope versus offshore seamounts
  The relationship between blue eye trevalla caught on the continental slope and on offshore seamounts
  is unclear and this was one of the major issues discussed at the workshop last April. We need to
  better understand what is the contribution of the large spawners concentrated on offshore seamounts
  to the productivity of the whole stock.

  Transferability of quota
  There are some concerns about the permanent transferability of quota between the trawl and non-
  trawl sectors because the differences in gear selectivity and fishing patterns between the two sectors
  may lead to significant changes in the size structure of commercial catches (for example, the potential
  increase in fishing pressure on large spawners on offshore seamounts could be detrimental to the
  stock). While this needs to be investigated further, solutions must also be worked out in the
  meantime to avoid the dumping of fish. The suggestion made by some fishers that
  controlled/seasonal transferability between sectors be permitted should be considered along with the
  control mechanisms that they have proposed at various meetings.


  6.                         IMPLICATIONS FOR MANAGEMENT


  Different size-dependent vulnerability of blue eye trevalla to different fishing gears must be taken into
  consideration when establishing quota transferability.

  Current management objectives, strategies and performance indicators must be reviewed to improve
  their relevance to the specific characteristics of the blue eye trevalla stock and its fishery.


  7.                         RESEARCH NEEDS

  The complexity of the size structure of blue eye trevalla catches needs to be examined in detail with regard
  to the type of fishing gear used, the ground/depth fished and the time of the year.
  Collection of data on the size and age composition of commercial catches taken by the various fishing gears
  should be accorded a high priority. This will also help assess the potential impact for the stock of the
  transferability of quotas between fishing sectors. The monitoring of quota-driven changes in the dynamics
  of the non-trawl fishing fleet and in the distribution of fishing effort is also needed.

  The species composition of hook catches has changed in recent years and the by-catch of quota and
  non-quota species should be monitored (e.g. catches of hapuku are increasing).


                       150
                                                                              actual TAC
Total catch (tonnes)




                       100                                                           approved TAC



  Blue Eye Trevalla
     50                                                                                                       55


                        0
Figure I Total annual verified trawl catches of blue eye trevalla calculated from the
         quota monitoring system (SEF2), and actual and appproved total allowable
         catches (TAC)




                              180
                              160
                              140
     av. catch rate (kg/hr)




                              120
                              100
                              80
                              60
                              40
                              20
                               0
                                    85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Figure II Average annual unstandardised catch rates of blue eye trevalla




56                                                                       SEF Species Summary 1999
Appendix A.1 : Recorded commercial catch history within the SEF area (tonnes) – Blue eye trevalla




                                      Commonwealth Records                                             State Records
                   Tr TAC                     Retained Catch                                          Retained Catch




                                                                                                                                        catch within SEF



                                                                                                                                                           discarded catch 1
                                                                                                                                         Estimated total
                                       Commonwealth
                                                      SEF 2 State




                                                                                                                                                              Estimated
                          Allocated




                                                        Waters
                 Agreed




                                                                    SEF 1




                                                                                      Total3
                                                                            Other
                                          SEF2




                                                                                                                                              area2
                                                                                                NSW
        Year




                                                                                                                    Tas


                                                                                                                              S.A.
                                                                                                          Vic
    1970
    1971
    1972
    1973
    1974
    1975                                               SEF not Established
    1976
    1977
    1978
    1979
    1980                                                                                          90         1       116          ?             207
    1981                                                                                          90        25       142          ?             257
    1982                                                                                          90        15       171          ?             276
    1983                                                                                          90        25       121          ?             236
    1984                                                                      45     45           90        72       181          ?             388
    1985                                                                      29     29          115        51       315          ?             510
    1986                                                              39      44     44           86        46       109          ?             285
    1987                                                              16      45     45          124        66       110          ?             345
    1988                                                             102     118     118          78       111       198          ?             505
    1989                                                              88     132     132          60        82       257          ?             531
    1990                                                              76             76          104        78       310         79             647
    1991                                                              94             94           99        73       261         72             599
    1992          125       125              60              1        49             61          101        86       328         57             633
    1993          125       147              77              1        59             78          146       115       242         53             634
    1994          125       135              89              2       110             91          190        80       330         38             729
    1995          125       139              67              1        58             68          184        87       355         22             716
    1996          125       147              81             <1        71             81          176        76       517         18             868
    1997          125       149             113             <1       103 357*        113         200        86       672         80            1040
    1998          100       116              96             <1        80             97            ?                380a
    Commonwealth Records:                                                           State Records:
       1984 - 1989 verified catch data                                                   1980 - 1997 NSW hook and trawl fishery1
       1990 - 1991 SEF logbook                                                           (80 to 84 estimate only)
       1992 - 1998 SEO3, SEF1 & 2 (1993/94 include                                       1980 - 1997 Vic hook and gillnet fisheries *
           catch recorded from state waters within SEF)                                  1980 - 1997 Tas hook and gillnet fisheries *
                                                                                         1990 - 1996 SARDI database*
           1997 - C/W Non-trawl logbook/SEF2                                           a - C/W non-trawl for Tas/Vic/SA
           * Duplicated on State logbooks                                              1
                                                                                         trawl fishery estimated from the difference between reported state
                                                                                    catches and SEF1 reported catch in Eastern A
                                                                                          * some data in financial years

   1.    Estimated from the SMP                                                                Abbreviations:
   2     Estimated by State Records from 1980 to 1983 from 1984                                     N/A = Not Applicable
Blue Eye Trevalla
   3
         onwards the total of the Commonwealth and the State records
         Total of the shaded cells
                                                                                                    ND = No Data Available                                               57
                                                                                                     ? = Available data not received
                                                      Appendix B : SEF Biological and Fishery Parameters
          Blue-eye Trevalla
          Table B.1.    Biological Parameters
                                                                    Weight
                       Growth            Longevity    Length -      (cm/kg)   Mortality   Reproduction              Recruitment
                                                                                                                                                                  Dataset
             Linf        K        t0      95% age        a            b          M         Age (R)       Size (R)   Age (C)        Size (C)         Author         year


           83.50       0.210                         8.657*10-3     3.1885                6-7 years       61cm                                   Webb (1979)
                                                                                                                                                 Winstanley &
            90.00                                                                                                                                Smith (1982)
           137.00
            (NZ)                                                                                                                                McDowall (1982)
                                                               -2
                                                      1.5*10        3.0410                                50cm                                    Jones (1988)


 Males     81.10       0.308    -0.63                9.626*10-3     3.1730                                                                       Horn (1988)
Females    86.10       0.308    -0.38                                                                                                            Horn (1988)
                                                                                                                                                Horn & Massey
                                                                                0.30      3-5 years                                                  (1989)
           107.00                                                                                                                               Williams (1989)




          Table B.2. SEF Agreed Biological Parameters
                       Growth            Longevity    Length -      Weight    Mortality   Reproduction              Recruitment
                                                                                                                                                                  Dataset
             Linf        K        t0      99% age        a            b          M         Age (R)       Size (R)   Age (C)        Size (C)         Author         year
 Males     98.90       0.080    -5.86           39     0.018        3.0160      0.20        8 to 9        62cm       2 to 3       46 to 50 cm    Baelde (1995)
Females    96.00       0.080    -5.25           42     0.018        3.0160      0.20       11 to 12       92 cm      2 to 3       46 to 50 cm    Baelde (1995)

58                                                                    SEF Species Summary 1999
Blue-eye Trevalla
Table B.3. SEF Data Availability
 Available data:                                                                                                 Author/Source
                        Pop Dynamics                             validation of aging needed
                        Monitoring
                        SEF Catch                                       1984-1998                                SEFAG 1998
                        Non-SEF Catch                                  1980 - 1997                               SEFAG 1998
                        Catch estimates                                 1970-1997                                SEFAG 1998
                        Nominal Effort                                 1985 to 1998                              AFZIS database
                        Stand Effort                           Processing 1985 to 1998 data                      BRS/SEFAG/Baelde
                        Size composition                            1950's and 1990's                            SEFAG 1998/ISMP
                        Age composition
                        Surveys                           1950's & 1990's (industry dependant)
                        Other

Table B.4. SEF Agreed Fishery Parameters
 Available data:                                                                                                 Author/Source

 Biomass Estimates
                        Virgin
                        1994
       Yield
                        MSY
                        MCY
                        CAY
    Z estimates         Z 1993                                                N 0.2                              SEFSAG 1995
    F estimates
                        Fmax
                        F0.1
                        Fmed
                        F1994
     Relative
    abundance
     estimates
                        Standard CPUE
                        trend

 Reference points
                        target
                        limit                                      30 % of virgin biomass                        SEFSAG 1994
 References
 Baelde, P. (1995). Assessment of the Blue-eye trevalla fishery and analysis of the impact of mid water trawling.
      FRDC report 91/20 May 1995
 Jones, G. K. (1988) The biological status of the deepsea trevalla (Hyperoglyphe antarctica ) offshore line fishery in
      South Australia. S.A. Dept. Fish. Discussion Paper.
 Horn, P.L. (1988) Age and growth of bluenose, Hyperoglyphe antarctica from the lower east coast, North Island ,
      New Zealand. NZ Journal Mar. Freshw. Res. 22(3) 369-78.
 Horn, P.L. & Massey, B.R. (1989) Biology and abundance of alfonsino and bluenose off the lower east coast,
      North Island, New Zealand. NZ Fish. Tech. Rep. 15.
 Mc Dowall, R.M. (1982) The centrolophid fishes of New Zealand (Pisces: Stromateoidei) J. Roy.Soc. NZ 12. 103-42.
 SEFSAG (1998) Stock Assessment Report - Blue-Eye Trevalla 1998.
 Webb, B.F. (1979) Preliminary data on the fishery for deepsea trevalla (Hyperoglyphe antarctica ).
      Tas. Fish. Res. 22. 18-29.
 Williams, H (1989) Background to the Tasmanian deepsea trevalla (Hyperoglyphe antarctica ) fishery.
      Report to DPFRG 28, Hobart .
 Winstanley, R.H. & Smith, G.J. (1982) Sarda line fishing cruise report No. 2: Western Victoria June-July 1980.
      Commercial Fish. Rep. Vic. 8.


   Blue Eye Trevalla                                                                                                           59
BLUE GRENADIER
1.       AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE
         INDICATORS *

Objectives

1.   To ensure that the blue grenadier resource is utilised in a manner consistent with the principles of
     ecologically sustainable development.
2.   To maximise the economic efficiency of the blue grenadier fishery
3.   To implement effective and efficient fisheries management on behalf of the Commonwealth.


Strategies
The above objectives will be pursued by:
1.   setting a TAC for the Commonwealth managed portion of the fishery that:
-    maintains the spawning biomass of blue grenadier above 40% of its virgin level (with an agreed
     probability)*
-    has an agreed probability that the spawning biomass of blue grenadier will not fall
     below 20% of its virgin level*
(objective 1)
2.   prioritising blue grenadier research in relation to the management objectives of the fishery:
-    SETMAC has given a high research priority rating to this species
(objectives 1, 2 &3)
3.   data collection
-   obtain estimates of total (retained and discarded) catch, catch rates and monitor shifts in effort and
changes in fishing practices
-    monitoring length and age distributions in commercial catches
(objectives 1&2)
4.   conduct annual stock assessment which provides estimates of:
-    provides estimates of spawning biomass at the onset of significant commercial fishing
-    provides estimates of the current spawning biomass of the fishery
-    provides estimates of recruitment
(objective 1)
5.   undertake economic research on the fishery to calculate GVP and monitor market prices for blue
     grenadier
(objective 2)


Performance indicators
1.   That the estimate of spawning biomass of blue grenadier is maintained above 40% of the virgin
     biomass level (level of probability to be determined*).
(strategy 1)
2.   That the estimate of spawning biomass of blue grenadier does not fall below 20% of the virgin
     biomass level (level of probability to be determined*).




60                                                                           SEF Species Summary 1999
(strategy 1)
3.   That data relevant to the annual assessment of blue grenadier has been collected and analysed, and
     considered by SEFAG and AFMA
(strategies 1, 2, 3, 4 & 5)


*Important notes:
Through discussions at BGAG, since its establishment in 1997, it has been agreed that the specific
wording of the previous objectives, strategies and performance indicators (1993-1998) was
inappropriate. In particular an apparent conflict existed between the previous objectives relating to the
winter spawning fishery and maintaining the ‗viability‘ of the non-spawning fishery. In addition, using
average annual trawl CPUE as a performance indicator for the non-spawning fishery was also agreed to
be inappropriate.
A formal stock assessment and risk analysis were conducted for the first time in 1998 and continued in
1999. In 1999 BGAG and SEFAG are in a position to provide some information about the status of the
blue grenadier resource in terms of biomass without specific reference to average annual trawl catch
rates as a performance indicator.
As the model requires specific quantities against which performance of the stock can be measured,
BGAG used the above performance indicators as interim measures until further consultation between
the BGAG, AFMA and SETMAC regarding actual levels of biomass and probability is undertaken and
specific levels to use in the long term are agreed.
AFMA will continue to undergo a process of refining the more generic management objectives for each
species and the fishery as a whole as part of implementing a process of overall Management Strategy
Evaluation.


2.   STOCK STRUCTURE AND LIFE HISTORY
Blue grenadier (Macruronus novaezelandiae) are found from New South Wales around southern
Australia to Western Australia, including the coast of Tasmania. Data support the hypothesis of a
single breeding population in Australian waters which is genetically distinct from the New Zealand
stocks.
Blue grenadier is a moderately long-lived species with a maximum age of about 25 years and age at
maturity of 4-5 years. Spawning occurs off western Tasmania between late May and early September
when dense aggregations form. Females are moderately fecund. Adults migrate to the spawning area,
apparently from throughout SE Australia, with larger fish arriving early in the spawning season. There
is also evidence of some spawning elsewhere in the SEF though the significance of this is unclear.
Blue grenadier are predators at the top of the food chain, taking a range of prey types including their
own young.

3.     THE FISHERY
Current situation
The 1998 SEF2 landed weight of of blue grenadier was 5,734 t, which was about 46% of the allocated
TAC of 12409t. It represents a continued increase in landings compared to 1997 (4534t). The 1999
TAC was 10000 t, with the allocated TAC being 11921t. 1997 landings from Victorian endorsed
vessels are less than 1 t and landings recorded for Tasmanian endorsed vessels decreased 12 t in 1996
to 9 t in 1997.
Industry members of BGAG noted that catches and catch rates have improved in the non-spawning
fishery and it was reported that discarding has decreased. Markets had improved particularly if the fish
are looked after. Holding blue grenadier on ice gave a better product than brine. Fishing practices of
some operators had changed such that smaller catches were taken to assist with raising product quality.
The issue of changed fishing practices (to avoid smaller fish) and increased mesh sizes on interpreting
trends in recruitment was raised. Overall the fishery is becoming more valuable, with 3 large vessels
anticipated to fish the spawning fishery in 1999. Markets outside Australia have improved with strong
demand in Europe for white fish. Quota prices have increased by 30%. It was suggested that a greater
proportion of the catch would come from the spawning fishery. . Industry reports that it anticipates the


Blue Grenadier                                                                                              61
10,000t TAC will be taken during 1999 due to the continuing development of the spawning fishery.
Industry stressed that with increased value and higher investment there would be greater scrutiny of
BGAG‘s assessments.
Additional comments were received during port visits in April 1999. Comments from fishers at
Beachport and Portland generally agreed with the above. Catches of blue grenadier were improving,
markets were accepting smaller fish and blue grenadier were attracting better prices.

ABARE TO UPDATE Blue grenadier is the second most important species in the South East Fishery
in terms of both quantity and value of catch. The gross value of recorded landings of blue grenadier
from the south east fishery in 1996 is estimated to be $7.6 million, around 17 per cent higher than the
previous year.
Blue grenadier is processed with relatively small quantities sold on both the Sydney and Melbourne
markets, mostly as headed and gutted product. In 1995 average market prices have generally ranged
between $2.10/kg and $5.70/kg, with prices on Melbourne markets being higher on average than
Sydney. The average price on the Melbourne market was $3/kg compared to average price on the
Sydney market of $1.90/kg. There are two seasons in the fishery with product from the summer season
being generally in better condition than product caught in the winter fishery. Prices for grenadier on
both markets increase substantially in late spring – early summer. The average price received by
operators after marketing costs have been deducted was about $2.50/kg.



4.     PREVIOUS ASSESSMENTS
Previous TACs were based on a biomass estimate derived from swept area trawl survey and commercial
logbook data from the early 1980s. There was no reliable estimate of virgin or current biomass, but
preliminary results from a two-stage acoustic survey and application of stock reduction analysis
methods suggested that virgin biomass was at least 30 000 t and that current biomass was between 30
000 and 230 000 t with 52 000 to 104 000 t corresponding to the most plausible set of assumptions.
The model estimated that a current biomass of 40 000 to 50 000 t (corresponding to a virgin biomass of
56 000 to 68 000 t) would be necessary to sustain a constant catch at 5 000 t through the year 2010.
More than double that amount (90 000 to 110 000 t) would be necessary to sustain a TAC of 10 000 t.
Blue grenadier were last assessed at a workshop in May 1997. Results indicated that two comparatively
weak year classes (1991 and 1992) had progressed through the non-spawning to the spawning fishery.
There was a large number of small (<50cm) fish caught across the fishery during 1996, indicating
improved recruitment. This led to increased discarding from the non-spawning fishery. The winter
fishery still contained a large proportion of old fish, although the proportion of fish older than 17 years
had declined in recent years. Whether this was due to fishing or past recruitment variability is
unknown. Egg production methods estimated the spawning biomass at between 100 000 and 135 000 t
(best estimates) with a confidence range of 55 000 to 180 000 t, which was comparable to earlier
acoustic estimates. Overall, the assessment, indicated that fishing had not had a major impact on the
stock as a whole, and a 10 000 t annual catch should be sustainable. This assessment was at odds with
the perceptions of some industry sectors and declining catch rates in the non-spawning fishery.
The Blue Grenadier Assessment Group (BGAG) was formed in 1997. The 1998 assessment included
1997 data from the SEF1 logbook and SEF2, and size and age composition and on-board (SMP)
observations of discarding rates were incorporated.. An age-structured ―synthesis‖ model was used to
assess the status of the stock and as the basis for population projections and a risk analysis evaluates the
consequences of different future levels of harvest by the spawning/non-spawning fisheries.
The spawner biomass was estimated to have declined continously from 1979 to 1997 although the
levels of fishing mortality had generally been less that 10%. One of the main resaons for the reductions
in recent years appeared to have been that recruitment from 1990 to 1994 was well below average. The
spawner biomass was predicted to recover once the strong 1995 ands 1996 year-classes reach age 5 and
entered the spawner biomass. The base case assessment which uses the egg production estimate of
female biomass as an absolute value, indicated that constant catch levels of 10,000t or less lead to a low
probability of dropping below 40% virgin biomass over the next 10 years although catch levels of
10,000t may lead to reductions below this level if continued over a longer period. The projections were
however, extremely sensitive to the egg production biomass estimates used in the assessment. For



62                                                                           SEF Species Summary 1999
example if the egg production estimates were not used in the assessment catches of 10 000t lead to a
high probability of dropping below 20% of virgin biomass. With an assessment which assumed the egg
estimates were twice their true value (half egg estimate scenario), catches of 15 000t lead to a greater
than 50% probability of dropping below 20% of virgin biomass whereas if the egg estimates were
assumed to be half of their true value (double egg estimate scenario) catches of 15 000t were unlikely to
reduce the biomass below 40% of the virgin level



1998 ASSESSMENT

Recent developments

The Blue Grenadier Assessment Group (BGAG) was formed in 1997. 1998 data from the SEF1
logbook and SEF2, and size and age composition and on-board (SMP) observations of discarding rates
were incorporated.. An age-structured ―synthesis‖ model was used to assess the status of the stock and
as the basis for population projections and a risk analysis evaluates the consequences of different future
levels of harvest by the spawning/non-spawning fisheries.

Assessment process
BGAG held meetings in November 1998, and April and June 1999.

Methods
SEF logbook data were examined. Unstandardised catch rates by zone were derived. Standardized
indices of relative abundance were estimated using GLM. Two fisheries were recognized: a spawning
fishery that is in fishing Zone 40 during the months of June, July, and August, and a non-spawning
fishery which is all other records from other areas and months (including June, July, and August not in
Zone 40).
Size and ageing data were used to assess changes in age composition between 1986 and 1998 for the
non-spawning fishery and 1984-1998 for the spawning fishery. Note: data were not available for all
years . The number of blue grenadier discarded by age group was calculated from ISMP data. Growth
curves were re-calculated.
An age-structured ―synthesis‖ model was used to assess the status of the stock and as the basis for
population projections using catch (including discards), standardised catch rates and catch-at-age data
as well as estimates of absolute abundance based on the egg production method. A risk analysis
evaluates the consequences of different future levels of harvest by the spawning/non-spawning fisheries.


Results
Total catches in 1998 were the highest recorded with the spawning fishery contributing over 2700t.
Unstandardised catch rates for the non-spawning fishery in the Western Zone and Eastern B have
shown slight increases over the last few years, but catch rates have remained stable (Eastern Zone B,
Western Tasmania) or declined (Eastern Tasmania). Unstandardised catch rates for the spawning
fishery were not presented because of the change in the fleet.
For the analysis of catch and effort data using GLM, vessels that were only present in the fishery for
one year were removed as constituting only statistical noise. Vessels were only included in the analysis
if there average catch, for the years they contributed to the fishery, was at least 20 tonnes.
The final model used in the GLM analysis was : Ln(CE) = constant + Year + Weeknumber + Vessel +
DepthCategory which described 55% of the catch-effort variation in the spawning fishery and 30% in
the non-spawning fishery. The main effect of the standardisation was to reduce the severity of the
apparent decline in catch-effort through time. In both fisheries catch-effort, after standardisation,
exhibits a steady decline, especially since 1991. However, in 1998 there appears to be an improvement
in catch rates in the non-spawning fishery. Standardised catch rates in the spawning fishery were more
variable than for the non-spawning fishery but were relatively low although stable during 1995-98.




Blue Grenadier                                                                                               63
The 1998 non-spawning fishery in all areas was dominated by fish from 45-65 cm reflecting the strong
recruitment seen in recent years. The 1998 size distribution for the spawning fishery was bi-modal.
Smaller 50-60cm fish were evident with few fish in the 70-80 cm size classes. The major mode was
dominated by fish between 90-100 cm. The length frequency was consistent with observed changes in
size/age composition seen in the fishery.
Total discards (approx 1300t) were lower in 1998 than in 1997(over 2,500t) as the dominant age class
(4s in 1998) have grown to a more marketable size. The age composition of the non-spawning fishery
was dominated by 3, 4 and 5 year old fish. These age classes were also evident in the spawning fishery
but the bulk of fish were aged between 10 and 14 years.
Growth curves were recalculated using all data collected from 1991, giving the following parameters:
       Linf = 100.02, K = 0.168, to = -2.01
The 1999 assessment of blue grenadier is based on an age- and sex-structured population dynamics
model that recognises the the fishery is divided into two components, used in 1998. The model
explicitly takes discards into account. Data inputs apart from the standardised catch rates and catch-at-
age matrices include mature female biomass from the egg-production estimates of 59080 t and 44915 t
for 1994 and 1995 respectively. The maximum age was taken as 20 and fish greater than 5 are assumed
to be mature. The steepness coefficient of the stock recruitment relationship was taken to be 0.9 and
recruitment variability has an SD of 1. M is estimated but assumed to lie between 0.2 and 0.3 with male
M 120% of females based on New Zealand studies.
In this assessment the egg production estimates relate to female spawner biomass only because of
uncertainties surrounding the sex ratios of spawning blue grenadier.
The spawner biomass is estimated to have declined continuously from 1979 to 1998 although the levels
of fishing mortality have generally been less than 10%. One of the main reasons for the reductions in
recent years was that recruitment from 1990 to 1994 was well below average.
Time-trajectories (1998 – 2018) of spawner biomass (females), the probability of remaining above 20%
of BF0, (female biomass before fishing) and the probability of remaining above 40% of BF0 for three
levels of constant catch: 5,000t, 10,000t and 15,000t were calculated. The split of the TAC between the
spawning and non-spawning fishery is assumed to be 75 : 25. Results are shown for the base-case
assessment and three sensitivity tests (ignoring the egg-production estimates, halving doubling the egg-
production estimates and doubling the egg-production estimates).
The model predicts a marked increase in spawner biomass as the strong 1995 and 1996 cohorts enter
the fishery followed by a gradual reduction in spawner biomass as these cohorts die out (Figure 1).
The ―shape‖ of the trajectories is similar for the base case and sensitivity tests but there are
considerable differences in the scale. For example, for the base case virgin biomass is estimated at
about 80,000 tonnes compared to 40,000t for the half egg estimate.
The 1999 assessment indicates that a TAC of 10,000t, for 20 ten years, has a low risk of reducing the
spawning biomass to below 40% of virgin biomass (Figure 2). However, the assessment is extremely
sensitive to whether the egg survey estimate is regarded as a measure of absolute or relative




64                                                                         SEF Species Summary 1999
Blue Grenadier   65
                                     160000
                                                                                                    TAC = 5 000t
                                     140000                                                         TAC = 10 000t
        Spawning biomass


                                     120000                                                         TAC = 15 000t

                                     100000

                                      80000

                                      60000

                                      40000

                                      20000

                                           0
                                            1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017




                                      1
                                                                                             TAC = 5 000
      P(spawning biomass < 0.4 B0)




                                     0.8                                                     TAC = 10 000
                                                                                             TAC = 15 000

                                     0.6


                                     0.4


                                     0.2


                                      0
                                       1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017




Figure 2. Projected spawning biomass for the base-case model under a range of future TACs;
                                      and the probability that spawning biomass will fall below 40* of B0 over a 20-year
                                      projection, for these TAC options.




abundance. For example, if the true abundance is half the egg estimate then the risks will be substantially
higher than shown in Figure 2: If the egg estimates underestimate the true biomass by 50%, catches of
15,000t will be sustainable whereas with the half egg estimate a 15000t TAC for 20 years leads to a high
probability of the biomass dropping below 40% of virgin biomass.


66                                                                                                 SEF Species Summary 1999
The 1999 assessment is more optimistic than that conducted in 1998 because the strength of 1994 year class
was not as weak as previously estimated, following the inclusion of 1998 data.


Uncertainties In Assessment
The results are extremely sensitive to the biomass estimates from the egg production method and the
assumptions used to derive these should be closely examined. The model is also very sensitive to the age
composition data for the most recent years (eg cf 1999 assessment with that in 1998).
Data inputs to the model are independent of sex although it is known that growth and natural mortality is
different between sexes. Length- and age-frequency data should be collected by sex. There is potential
bias by using calender year rather than an annual period which better reflects the life history of the animal.
There are indications that the growth of different cohorts is not constant as is assumed here, and may be a
function of cohort size. Year specific lengths-at-age should overcome this potential bias.
Use of CPUE as an index of stock abundance in an aggregating fish species is known to be unreliable and
may not reflect actual changes in abundance in the winter spawning fishery, particularly given the use of
new midwater nets. The model assumes that standardised catch rates are linearly related to abundance.
This assumption particularly for the spawning fishery should be closely examined.

6.     IMPLICATIONS FOR MANAGEMENT
There are two distinct components to the blue grenadier fishery within the SEF. The non-spawning fishery
concentrates principally on 4-5 age classes of juveniles and sub-adults. There is considerable variation in
recruitment and because of the relatively few age classes in this fishery, there is considerable variability in
annual catch rates. The winter spawning fishery targets mature fish and, typically, catches contain over 10
age classes. Catches in this fishery contain a far greater proportion of large and old blue grenadier than is
seen in the non-spawning fishery. Industry reports that it anticipates the 10,000t TAC will be taken during
1999 due to the continuing development of the spawning fishery.
The 1999 assessment of blue grenadier uses the age-structured ‗synthesis‘ model developed during 1998
with the inclusion of 1998 data. The assessment considers fishing during the spawning season off Western
Tasmania and that at other times/places separately. The model uses catch (including discards),
standardised catch rates and catch-at-age data as well as estimates of absolute abundance based on the egg
production method. A risk analysis evaluates the consequences of different future levels of harvest by the
spawning/non-spawning fisheries
The catch rate data were standardized to remove some of the impact of changes in fishing practices/fleet
composition. Standardised catch rates in the non-spawning fishery declined from 1991 due to a series of
weak year-classes entering the fishery. 2 strong year classes are currently entering the fishery and catch
rates consequently rose in 1998. Discarding in the non-spawning fishery was extremely high during 1997
and 1998, estimated at over 2500t and 1300t, respectively. This discarding is a cause of concern because
of the waste of future yield, the potential impact on future egg production (particularly for poor year
classes) and increased uncertainty of stock assessments. The Group highlighted the importance of the
discard data provided by ISMP to the blue grenadier assessment, particularly as it relates to recruitment.
Standardised catch rates in the spawning fishery were variable but were relatively low, although stable,
during 1995-98. As the strong year classes are anticipated to enter the spawning fishery during 1999 and
2000, it is expected that catch rates will rise.
The spawner biomass is estimated to have declined continuously from 1979 to 1998 although the levels of
fishing mortality have generally been less than 10%. One of the main reasons for the reductions in recent
years was that recruitment from 1990 to 1994 was well below average. The spawner biomass is predicted
to recover once the strong 1995 and 1996 year-classes reach age 5 and enter the spawner biomass. The
1999 assessment is more optimistic than that conducted in 1998 because the strength of 1994 year class was
not as weak as previously estimated, following the inclusion of 1998 data.
The 1999 assessment indicates that a TAC of 10,000t, for 20 ten years, has a low risk of reducing the
spawning biomass to below 40% of virgin biomass. However, the assessment is extremely sensitive to
whether the egg survey estimate is regarded as a measure of absolute or relative abundance. For example,
if the true abundance is half the egg estimate then the risks will be substantially higher than shown in Figure
x: If the egg estimates underestimate the true biomass by 50%, catches of 15,000t will be sustainable



Blue Grenadier                                                                                              67
whereas with the half egg estimate a 15000t TAC for 20 years leads to a high probability of the biomass
dropping below 40% of virgin biomass.

7.        RESEARCH NEEDS

Basic data needs and collection
High Priority
 Essential – annual data collection, all sectors and areas through ISMP
           Catch and effort (including analysis using GLM)
           Age- and size-composition of the landed catch (by sex if possible)
           Discards (magnitude and age- / size-composition)
    All onboard data should be recorded separately for demersal and midwater trawling. As an interim
     measure skippers will be asked to record midwater shots as null gear type in SEF1.
    Analysis of catch and effort data using New Zealand data to standardise the large vessels entering the
     spawning fishery.
    Additional sex ratio data should be collected during 1999 for input to the stock assessment.
Refinement of analyses
High Priority
    Catch and catch-at-age data
     a)    The catch-at-age data need to re-calculated to take into account annual weight at age data as there
           are indications cohort growth is variable and hence that a single growth curve is likely to be
           inappropriate.
     b) The age-length keys, currently based on calendar years, should be reworked to a 1 June to 30 May
        year to reflect winter spawning.
     c)    Length weight relationships and conversion rates (partial weight to whole fish weight) should be
           re-calculated.
    Age reading errors should be quantified and explicitly included in the model.
    The model is extremely sensitive to the biomass estimates for 1994 and 1995 derived from the egg
     production method. Whether a third egg survey is warranted needs careful consideration. The power
     of such a survey during the predicted peak biomass in 2001 to fix the scale of the projections needs to
     be evaluated. In addition, a similar study should be undertaken to evaluate a second acoustic survey in
     2001.
Further model development, including:
    An evaluation of alternative performance indicators and harvest strategies should be conducted. Such
     an evaluation would need to consider implications of highly variable recruitment, explicitly consider
     constant catch versus fixed harvest rate strategies and take account of the fact that catches have
     historically been much small than TACs.
    The sensitivity of the model to a variety of alternative relationships between standardized catch and
     abundance should be examined. The current assessment assumes that catch rate is linearly
     proportional to abundance.
    The trajectories of biomass in the absence of fishing should be computed.
    Modification of the model to handle a 1 June – 30 May year, cohort specific growth rates, and age-
     reading error.
    The implications of constraining selectivity ogives needs to be assessed.

Specific research needs
High Priority


68                                                                          SEF Species Summary 1999
   Development of a recruitment index:
     Consolidate all existing trawl survey data from Victoria (eastern and western Bass Strait), Tasmania,
     the Kapala surveys, and CSIRO to provide additional information on recruitment variability prior to
     the existing datasets.

          Development of a cost-effective means of monitoring future recruitment. This should include
          the implications of changed mesh sizes (to be monitored by the ISMP) and any trends in size by
          depth.
   Improve the information on the spawning behaviour and reproductive biology, including fecundity
    estimates, maturity ogives, and the proportion of non-spawners with a view to reducing the uncertainty
    about the biomass estimates based on the egg production method.

Generic (SEFAG-level) research needs
 SEFAG needs to consider a number of issues relating to Management Objectives and Performance
  Indicators. It is not clear that these are well understood as is the differences between risk assessment
  and harvest strategy evaluation.
 Assessments for blue grenadier, blue warehou and school whiting have all identified considerable
  errors/inconsistencies in SEF1 records. This issue needs to be addressed as a matter of some urgency.
Note: A number of projects have commenced since being identified in last year‘s assessment:
 Evaluation of gear configuration to reduce discards. This project funded by FRDC has commenced.
 Evaluating and designing fishery-independent surveys. An ARF-funded desktop study commenced in
  1999.
 Production parameters for similar species. An ARF-funded desktop study of fisheries literature
  commenced in 1999.




Blue Grenadier                                                                                           69
                        14000
                                                                                                                     actual TAC
                        12000
 Total catch (tonnes)




                        10000
                                                                                                                     approved TAC
                                  8000

                                  6000

                                  4000

                                  2000

                                                          0
                                                                 1992   1993   1994   1995   1996       1997       1998
                                                                                      Year

Figure I Total annual verified catches of blue grenadier calculated from the quota
         monitoring system (SEF2), and actual and approved total allowable catches
         (TAC)




                                                          4.5
                        standardised catch rate (kg/hr)




                                                          4.0                                       spawning
                                                          3.5                                       non-spawning
                                                          3.0
                                                          2.5
                                                          2.0
                                                          1.5
                                                          1.0
                                                          0.5
                                                          0.0
                                                                85 86 87 88 89 90 91 92 93 94 95 96 97 98 99


Figure II Average annual standardised catch rates for the spawning and non-
          spawning blue grenadier fisheries.




70                                                                                                             SEF Species Summary 1999
                 Appendix A.1 : Recorded Commercial Catch History within the SEF area
                 (tonnes) – Blue Grenadier

                                       Commonwealth Records                                               State Records
                         TAC                   Retained Catch                                            Retained Catch




                                                                                                                                       catch within SEF



                                                                                                                                                          discarded catch3
                                        Commonwealth




                                                                                                                                        Estimated total
                                                       SEF 2 State




                                                                                                                                                             Estimated
                           Allocated




                                                         Waters
                Agreed




                                                                                      Total1
                                                                      SEF 1


                                                                              Other
                                           SEF2




                                                                                                   NSW




                                                                                                                                             area2
    Year




                                                                                                                      Tas


                                                                                                                               S.A.
                                                                                                             Vic
1979
1980
1981
1982
                                                       SEF not Established
1983
1984                                                                          1342    1342                                                    1342
1985                                                                          1201    1201                                                    1201
1986                                                                 1460     1476    1476                                                    1476
1987                                                                 2249     2122    2122               ?     15                             2137
1988                                                                 1828     2171    2171               ?     25        1                    2197
1989                                                                 1895     1964    1964               ?     31        1                    1996
1990                                                                  2287            2287               ?     28       48                    2363
1991                                                                  3668            3668               ?     22       <1                    3690
1992          5000         5000           3289                 0     2471             3289               ?      5       <1                    3294
1993          5000         5495           3348                11     2472             3359               ?      9        5                    3373
1994          10000       12351           3155                 0     2315             3155               ?      8        9                    3172
1995          10000       12280           2761                <1     1929             2761               ?      2        4                    2767
1996          10000       12634           3038                 1     2278             3039               ?      3       12                    3054
1997          10000       12496           4534                 4     3627             4538               ?     <1        9                    4548
1998          1000        12409           5733                <1     4233             5734               ?      ?       <1

 Commonwealth records:                                                                         StateRecords:
           1984 - 1989 verified catch history                                                       1988 - 1990 Tasmanian inshore
           1990 - 1991 SEF Logbook                                                                  1990 - 1998 Tasmanian DPI
           1992 - 1998 SEF 2 Records                                                                1987 - 1997 Victorian MAFRI




1.     Total of shaded cells                                                                   Abbreviations:
2.     1979 - 1983 DPIE Tasmania trawl logbook and Tas and                                          N/A = Not Applicable
       Vic landings                                                                                 ND = No Data Available
3      Estimated from the SMP                                                                        ? = Available data not received




Blue Grenadier                                                                                                                                      71
BLUE WAREHOU

1.        AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE
          INDICATORS

Objectives
Ongoing
1. To ensure that the blue warehou resource is utilised in a manner consistent with the principles of
   ecologically sustainable development.


Immediate objective
2. To ensure that the spawning biomass of blue warehou does not significantly decline below its 1994
   level:
       current jurisdictional boundaries and varying approaches to management by the States and
        Commonwealth need to be reconciled if this objective is to be achieved:
              noting that the gill net catch of blue warehou is a significant proportion of the total catch.
Ongoing
3. To maximise the economic efficiency of the blue warehou fishery.
4. To implement effective and efficient fisheries management on behalf of the Commonwealth.

Strategies
The above objectives will be achieved by:
1. setting a TAC for the Commonwealth managed portion of the fishery that:
       west of Bass Strait, maintains the catch per unit effort (CPUE) above its lowest annual average level
        from 1986 to 19941
       east of Bass Strait, CPUE rates do not significantly decline below their average 1994 level2
      [Note that the TAC currently only applies to the trawl sector of the fishery within the SEF, excluding
      the southern Remote Zone].
      (objectives 1 & 2)
2. managing all sectors of the blue warehou fishery in a complementary manner and, where appropriate,
   applying a TAC and ITQs to the fishery for all sectors under Commonwealth jurisdiction.
   (objectives 1, 2 & 4)
3. prioritising blue warehou research in relation to other SEF species:
       SETMAC has given a high research priority rating to blue warehou
       (objectives 1, 2, 3, & 4)
4. data collection:
     (i) obtaining estimates of catch and catch rates, and monitoring shifts in effort and changes in fishing
     practices
     (ii) monitoring length distributions in commercial catches and undertaking ageing as required
     (iii) obtaining estimates of the spawning biomass of the fishery through catch-at-age analyses, using
     1993 as a baseline figure in the absence of any capacity to determine spawning biomass at the onset of
     significant commercial fishing.
     (objectives 1 & 2)
5. undertaking economic research on the fishery to calculate GVP and monitoring market prices for blue
   warehou.
   (objective 3)


1
     there is uncertainty about the stock structure of blue warehou in the SEF, but as there are different indicators of the impact of
     fishing in the eastern and western areas of the fishery, the strategies are framed accordingly
2
     in the absence of estimates of current or initial spawning biomass an assumption has been made that a relationship exists
     between CPUE, abundance and biomass



72                                                                                             SEF Species Summary 1999
Performance indicators (1995 - 1996)
1. (i)   That the current annual CPUE for west of Bass Strait is above its lowest annual average from
     1986 to 1994
     (ii) That CPUE for east of Bass Strait has not declined below its average 1994 level
     [Note that if CPUE declines below 1986-1994 levels this would not necessarily result in a reduction in
     the TAC but would require a report to be made on the possible causes of the decline (within 12 months
     of the decline being brought to the attention of SEFAG/AFMA). The report would form the basis of
     discussion as to whether management arrangements, including TACs, for blue warehou needed to be
     reconsidered.]
     (strategy 1)
2. That all sectors of the fishery are managed in a complementary manner.
   (strategy 2)
3. Data relevant to the annual assessment of blue warehou has been collected and analysed, and considered
   by SEFAG.
   (strategies 1, 3, 4 & 5)
4. The actual trawl catch relative to the trawl TAC
   (strategy 1)


Important Note
The Blue Warehou Assessment Group (BWAG) was established in 1997. Through discussions at BWAG
meetings, it was agreed that there is considerable doubt that the specific wording of the current objectives,
strategies and performance indicators for this fishery are appropriate. Members of BWAG have agreed that
the work both undertaken and completed by the Group had superseded the current objectives, strategies and
indicators for the fishery. Using average annual trawl CPUE as a performance indicator for the fishery was
also agreed to be inappropriate.
A formal stock assessment and risk analysis were conducted for the first time in 1998 and continued in
1999. The models used in the assessment require specific quantities against which performance of the
stock can be measured. BWAG recommended that the following interim performance measures be used for
the 1999 assessment:
    P(B > B97) – the probability that the projected biomass is greater than the biomass in 1997
    P(B > min [B91 > B97]) – the probability that the projected biomass is greater than the minimum
     biomass between 1991-97
    P(F < M) – the probability that the projected fishing mortality is greater than natural mortality

A formal revision of the management objectives, strategies and performance indicators will be undertaken,
during 1999/00, through consultation with AFMA, SETMAC, SENTMAC and the BWAG.

AFMA will undergo a process of refining generic management objectives for each species and the fishery
as a whole. This will be a part of developing a process of overall Management Strategy Evaluation.



2.      STOCK STRUCTURE AND LIFE HISTORY
Blue warehou are found in continental shelf and upper slope waters throughout south-eastern Australia
(NSW, Victoria, Tasmania and South Australia). The species is also found in New Zealand waters. Adults
are caught in depths to 500 m, although most commercial catches occur from 50 m to 300 m. Spawning is
thought to occur during winter in various locations throughout the adult distribution of the species. Small
juveniles are pelagic, commonly occurring in association with jellyfish in open coastal waters, and sub-
adults often occur in the sheltered waters of large marine embayments. Growth is rapid, with a mean length
of about 20 cm LCF being attained after one year end the species has a maximum age of about 10 years.
Age of maturity occurs at 3 - 4 years. There have been no studies on the stock structure of this species in
Australian waters. Of particular interest is the relationship between stocks east and west of Bass Strait -
these two areas currently providing 50% - 75% of total annual commercial catches. Given current


Blue Warehou                                                                                              73
perceptions that this species is capable of being highly mobile, and the apparently broad distribution of
breeding locations, blue warehou have to date been assumed to be a single stock for fisheries assessment
and management purposes.
Blue warehou are closely related to spotted warehou and mixed catches do occur. This has led to confusion
between the species in commercial catch statistics. This was most apparent in comparisons between
logbook and ‗verified‘ catch data in the late 1980s. Also, early statistics were recorded for all warehou
species combined, commonly referred to as ‗Tassie trevally‘.


3.     THE FISHERY

Current situation
The 1998 SEF2 landed weight of blue warehou was, for trawl, 932 t (921t Commonwealth waters and 11 t
State waters), which was about 87% of the allocated TAC of 1075 t. It represents an increase in landings
compared to 1997 (794t). The 1999 TAC was 718 t, with the allocated TAC being 897t (includes cross
sector leasing).
1998 landings from the non-trawl sector were 78t, representing only about 7% of the allocated TAC (1168t)
1998 landings were considerably lower than in 1997 (273t). The global TAC for 1999 was set at 1750t
(718t trawl and 1032t non-trawl). Landings recorded for Tasmanian endorsed vessels showed an increase
from 127 t in 1997 to an estimated 200t in 1998.
Industry members of BWAG noted that the 1998 non-trawl fishery for blue warehou was very poor. The
1998 season was short and catches low despite industry expending considerable effort to find fish. They
indicated that individual schools of blue warehou are producing smaller catches over times; schools are
apparently getting smaller and today only one fishing operation can be done on a school. It was noted that
searching time had also increased. The non-trawl sector was very pessimistic about blue warehou believing
that it will be become a trawl-only species with transfer of quota from non-trawl to trawl.
Portland trawlers had no problem catching their quota with leasing from the east. Very little was caught off
Bermagui. Eden catches were good between September and October. It was noted that trawl catches off
Tasmania during December were very poor.
Additional comments were received during port visits in April 1999. Portland fishers noted that the
availability of blue warehou had increased in 1997 and 1998 and the size of fish had also increased.
ABARE TO UPDATE The average market price (net of marketing charges) received by trawl operators for
blue warehou in 1996 was estimated to be about $1.94/kg, a slight decrease on that received in 1995
($2.2/kg). The wholesale market value (net of marketing charges) of recorded SEF trawl landings of blue
warehou in 1996 was estimated to be about $1.7 million. This was about 20% lower than in 1995, due to
increased prices and catch. Marketing charges were estimated to be equivalent to about 21% of the average
gross market price in 1994. (UPDATE)
Blue warehou caught by gillnets are larger on average than trawl-caught fish (due to the selectivity of the
mesh nets used), and therefore usually command a higher average price under the same market conditions.
The estimated gross market value (before marketing charges) of gillnet catches for 1995 was about $843
000 which, together with an estimated gross market value of $3.3 million for the SEF trawl catch, gives a
1995 total commercial catch value (before marketing charges) of about $4.1 million. (UPDATE)
Fishers often grade blue warehou (small, medium and large) as prices are generally higher for large fish.
For example in 1993, the average price paid for small, medium and large fish by one trader at the
Melbourne Fish Market was $1.36, $2.34 and $2.97, respectively.

4.     PREVIOUS ASSESSMENTS

Mesh selectivity studies showed that the size distribution of fish taken by gillnet vessels - characterised by
generally larger fish than those taken by trawlers - was due to mesh selectivity, as smaller fish do occur on
the reefs fished. Trawl catches of blue warehou were dominated by fish of 2-4 years old whereas for gillnet
catches it was 4-6 years old. Maximum recorded ages from trawl and gillnet catches were 7 years and 9
years respectively. Re-analysed estimates of total mortality (Z) for trawl caught blue warehou were higher
than previously reported, ranging from 1.7 to 2.3.
The 1994 assessment included a more detailed examination of SEF catch, effort and catch rate data up to


74                                                                         SEF Species Summary 1999
1993. It also included examination of trawl and gillnet size composition data from 1991 to early 1994, an
analysis of yield-per-recruit using a simple age-structured model for a range of mortalities and ages at first
capture, and a dollars-per-recruit analysis to determine the optimum capture size for marketing purposes.
The 1995 assessment included an examination of SEF catch, effort and catch rate data and size and age data
up to 1994, and a preliminary GLM analysis. Management options including the introduction of a
minimum legal size were examined.
The 1995 blue warehou catch rate data confirmed previously observed declining annual trends east and
west of Bass Strait and in eastern Tasmanian waters after what appeared to have been a peak in
abundance/availability in 1989 or 1990. The 1995 data also confirmed that in most cases declines in winter
and spring catch rates contributed most to the annual trends. Examination of spatial trends in the trawl
fishery using GIS showed that the declines in catches and catch rates occurred despite the trawl fishery
expanding from east and west of Bass Strait in 1986 to include eastern and western Tasmania. There were
pronounced seasonal differences between areas with catches not being recorded off south-east Tasmania
during winter. The relationship of fish in these areas was unknown but the data were not inconsistent with a
north-south migration.
General linear modelling, performed using the approach developed by Klaer and which included all data
from all zones, showed a marked decline following a peak in 1989-1990. The relative year effect stabilised
after 1993.
The 1997 assessment concluded that trawl catch rates are at low levels or continue to decline; AFMA‘s
performance criterion was triggered with the 1996 catch rate for the trawl fishery as a whole, falling below
those for 1986 to 1994; gillnet catches were extremely low compared to peak annual catches; there was a
high proportion of juveniles in trawl catches both east and west of Bass Strait, with a consistent decline to
smaller, younger immature fish (1-3 year olds) west of Bass Strait.
The Blue Warehou Assessment Group was established in 1997 and conducted the first formal assessment of
the species in 1998. A fleet-disaggregated Virtual Population Analysis was applied to catch-at-age and
standardized fishing effort data for the blue warehou resource off southern Australia. The analysis is based
on three fleets (―western trawl‖, ―eastern trawl‖ and ―non-trawl‖).
For the eastern trawl fleet, standardised CPUE initially increased steeply to a peak in 1990 dropping to a
lower level by 1992 and stayed roughly at the same level since. The trend in CPUE for the western fishery
was one of continuous decline from 1991 with a single year of upturn in 1997. The age-composition data
suggests that this was due to a strong year class entering the fishery and growing into its second year.
Standardised CPUE for the non-trawl fleet was variable up to 1990 but subsequently declined.
The assessment used data up to, and including, 1997. The results suggested that the biomass (exploitable
and spawner) dropped markedly from 1991 to 1994 and had stabilised (or is increasing) since. Population
projections were conducted for a range of catches for 1999 (2500t – 1000t). These projections were
influenced by the catch taken in 1998. The 1998 trawl sector catch was assumed to be the TAC split 40:60
between the western and eastern fleets. For the projections, non trawl catches were based on 100%, 50% or
75 % of the TAC being taken. In addition to these catches, the non-trawl catch off Tasmania was assumed
to be 150t per annum and this catch was assumed not be part of the TAC.
If the total SEF 1998 TAC was caught, the average fishing mortality (ages 3 and over) was greater than
natural mortality with a greater than 50% probability for all except the lowest level of TAC (1000t).
However, for all levels of TAC for 1999, the probability of the biomass dropping below the lowest level
over the period 1991 – 97 was less than 50%. With 50% of the non trawl TAC being caught, the average
fishing mortality was greater than natural mortality with a greater than 50% probability for TACs of 1750t
or over and the probability of the biomass dropping below the lowest level over the period 1991-97 was
25% or less. Results for the 75% scenario are intermediate. The results suggested that catches larger than
1000t were currently ‗sustainable‘ (defined as not leading to a high probability of dropping below the
lowest biomass over the period 1991 – 97). However, they were probably not ‗sustainable‘ over the
medium term.

The results suggested that the blue warehou population is influenced strongly by variation in recruitment.
One implication of this is that higher yields can be achieved by conducting regular assessments and
modifying TACs in response to changes in year-class strengths. However, future assessments will need to
consider the implications of shifts in effort between sectors.




Blue Warehou                                                                                               75
5.     1998 ASSESSMENT


Recent developments
The Blue Warehou Assessment Group (BWAG) was formed in 1997. In 1998, a fleet-disaggregated
Virtual Population Analysis was applied to catch-at-age and standardized fishing effort data. The 1998
assessment of blue warehou was extended by using an ‗integrated analysis‘ approach. 1998 data for the
SEF logbook, Victorian and Tasmanian non-trawl landings, and size and age composition and on-board
(SMP) observations of discarding rates were available. Data for the trawl fishery off Portland in 1987 and
1998 was also included.

Assessment process

BWAG held meetings in November 1998, and April and June 1999.

Methods
Catch and effort data were examined by area and season for the period 1986-98. GLM analysis was
applied to SEF trawl logbook data to provide standardised fishing effort and relative CPUE.. For non-
trawl, the Victorian component of the non-trawl sector was used for the period 1986-1996, and GNO1 for
1997 and 1998. GLM analyses were used to describe trends in standardised CPUE. Size and ageing data
were used to assess changes in age composition between 1991 and 1998. The number of blue warehou
discarded by age group was calculated. Size and age data from 1987 and 1988 were included. An
integrated analysis approach was applied to these data. This approach is more flexible that the fleet-
disaggregated Virtual Population Analysis used in the 1998 assessment. The current assessment uses
length and age data separately, accounts for errors in ageing, and datasets with low sample sizes need not
be included, unlike the VPA. The analysis is based on four fleets (―western trawl‖, ―eastern trawl‖, ―non-
trawl‖ and the Tasmanian meshnet fishery).

Results
Unstandardised trawl catch rates in the main areas (Eastern B and West) rose slightly in 1998 but have been
relatively stable elsewhere.
Two fisheries were recognized for the trawl sector. These were the eastern fishery including zones 10, 20,
and 30, and the western fishery which was the zones 40, 50, and 60. All analyses were restricted to vessels
that had been in the fishery for more than 2 years (had more than 5 records per year and an average annual
catch of greater than 9t). Comparisons were made between analyses where all data were used and those in
which data were restricted to catches over 50kg. Standardization had little effect on the catch effort rates
for the eastern fishery as the GLM only accounted for a maximum of 7.2% of the variation in the data,
when only catches greater than 50kg were considered, and 18.1% when all data were used. Standardised
CPUE initially increases to a peak in 1990 dropping to a lower level by 1992 and remaining relatively
stable from 1994. The optimum model was Ln(CE) = Constant + Year + Depth + Vessel + Zone. The
decline was more marked when all data were used in the analysis. In the western fishery, the above GLM
using all data accounted for 34.9 % of the variation in the data. With catches greater than 50kg, the GLM
described 24.1% of the data‘s variability. The trend in catch-effort was one of continual decline from 1991
with an upturn in 1997 and 1998. . The age-composition data suggest that this is due to a strong year class
entering the fishery and growing into its second and third year.
The best estimate of the blue warehou catch from the non-trawl sector in 1998, was 280t (including
Tasmanian inshore catches, 200t), lower than of the 1997 catch of about 400t and considerably lower than
peak catches in 1990 and 1991 (1918 and 1540 t, respectively).
Standardised CPUE for the non-trawl fleet was variable up to 1990 but has subsequently declined. There
was a slight upturn in 1997, followed by a decline in 1998. Because the non-trawl effort data do not
include searching time, the results represent the minimum decline.
Percentage length frequency distributions for blue warehou landed at Portland in 1987 and 1998 ranged in
length from 25 to 55 cm LCF. The 1997 distribution was bi-modal with modes at 34 and 45 cm. The 1988
distribution has a single mode at 45-48 cm. Ages 4-6 were the most numerous age groups in the catches.



76                                                                        SEF Species Summary 1999
1998 port-based length frequency distributions for the trawl sector were variable. For blue warehou landed
at Eden, the 1998 length frequency was bi-modal with a mode at 33-34 cm LCF and a second mode at
about 45 cm. Lakes Entrance landings showed a single mode of similar size to that at Eden of about 45 cm.
Portland fish ranged in length from 28 to 50 cm LCF with most fish in the 32-42 cm size classes. There
were suggestions of modes at 35 and 39 cm LCF. All size distributions indicated a slight increase in
overall length compared to 1997.
The sample size for mesh net caught fish was fairly small but the size distribution was consistent with
earlier years, with fish ranging in length from 40-55 cm LCF and a single mode at 47-49 cm.
During 1998 it was estimated that about 73 t were discarded, most in the West (53 t) and Eastern B (13 t).
Off the east coast, discarded fish were generally small (< 37 cm). Off Portland, discarded fish were less
than 38 cm LCF
The age composition of trawl catches continued the trend seen in recent years as the age classes that
recruited in 1995 and 1996 move through the fishery. This is consistent with size distributions, particularly
in the East. The age composition from mesh net catches was stable.
An integrated analysis approach was applied to these data. This approach is more flexible that the fleet-
disaggregated Virtual Population Analysis used in the 1998 assessment. The current assessment uses
length and age data separately, accounts for errors in ageing, and datasets with low sample sizes need not
be included, unlike the VPA. The analysis is based on four fleets (―western trawl‖, ―eastern trawl‖, ―non-
trawl‖ and the Tasmanian meshnet fishery).
Natural mortality was set at 0.45 for all ages. A growth curve was not used (except in sensitivity analyses)
but mass-at-age was calculated directly from observed mean lengths-at-age and the length weight
relationship.
The results suggest that the spawner biomass peaked between 1987 and 1989 dropped markedly to 1994
and has remained relatively stable since (Figure 1). The spawner biomass in 1998 was about 30% of peak
levels. The 1996 cohort (fish aged 3 in 1998) is the strongest detected to date.
A risk analysis based on 5 and 10-year projections was undertaken. . The risk associated with different
levels of TAC is determined using three performance indicators (reported for t=2003 and t=2008
corresponding to 5 and 10 year projections):
             ~ ~
    (i)    P(Bt  B1997 ) - the probability that the spawning biomass during year t is greater than that in
           1997.
              ~         ~
    (ii)   P( Bt  min( By : y  1991,92..,97)} - the probability that the spawning biomass during year t
           is greater than the lowest spawning biomass over the period 1991-97.

    (iii) P ( Ft  M ) - the probability that the arithmetic average fishing mortality on mature animals
           during year t is less than natural mortality:

The projections require the population projections were conducted for a range of catches by fleet for 1999
and assumptions regarding the split of future TACs to fleet:
(a) 1999 catches


                Option                        Trawl                    Non-trawl       Tasmania
                                     East              West
                   A                430.8              287.2             132               250
                   B                 600                400              100               250
                   C                1020                680              100               250
                   D                 780                520              200               250



                    (b) the split of future catches by fleet
                          Option                        Trawl                  Non-trawl
                                               East             West

Blue Warehou                                                                                                  77
                          1                0.54              0.36               0.1
                          2                0.36              0.54               0.1
                          3                0.25              0.16               0.6


The results were insensitive to the 1999 catch and the split of this catch between fleets but were very
sensitive to the projection period and the performance indicator chosen (Figure 2). In all cases, the 5-year
projections are more optimistic. For example, a Commonwealth TAC of 2000t leads to greater than 50%
probability of the biomass being above the minimum biomass between 1991-1997 for a 5-year projection
but a less than 30% probability for a 10-year projection. For the fishing mortality indicator, the 5-year
projection gives a less than 20% probability of fishing mortality being less than natural mortality for a
2000t TAC, but a less than 10% probability for the 10-year projection. The differences between
projections reflect the influence of the 1996 cohort as it passes through the fishery. The results were
consistent for a range sensitivity analyses. In summary, the (Commonwealth) TAC required to achieve a
50% probability of satisfying each performance indicator ranges from less than 1300t to about 2000t.




78                                                                         SEF Species Summary 1999
                          10000

                          9000
                          8000
    Spawner biomass (t)



                          7000
                          6000

                          5000

                          4000
                          3000

                          2000
                          1000

                             0
                             1986   1988   1990   1992   1994       1996       1998
                                                  Year


Figure 1. The time trajectory for spawner biomass (solid line) and approximate 90% probability intervals
(dotted lines).




Blue Warehou                                                                                           79
Figure 2. Probability of satisfying the three performance indicators as a function of the TAC set for the
Commonwealth fishery (0-2500t), where the underlying population dynamics parameters are based on the
base-case analysis. Results are shown for 5- (solid line) and 10-year (dotted line) projection periods (2003
and 2008 respectively).




80                                                                         SEF Species Summary 1999
Uncertainties in assessment
For the analyses of trawl catch effort data for the West, the number of observations in 1986 and 1989 are
relatively few and as a result the relative abundance index for these years are very sensitive to the particular
analysis performed. It is concluded that these points should not be included in further analyses as being too
poorly represented across all factors to provide adequate parameter estimates. As the VPA only requires
catch-effort data from 1991 this is not a major concern. It should also be noted that the output from a GLM
does not guarantee that a relation exists between stock size and standardised catch per unit effort. In the
SEF, the contribution due to changed fishing practices after the introduction of quota cannot be discounted.
For the non-trawl there is no measure of searching time.
The fits to the length-composition data (both landed and discarded) are relatively poor. Consideration
should therefore be given to allowing selectivity to vary inter-annually (to some extent). The current model
assumes that spawning occurs in the middle of the year, which implies that an animal is age zero for only
half a year. This problem can be rectified by defining the ―year‖ to run from July to June.
It seems likely that growth changes inter-annually and as a function of cohort size (particularly for small
animals). The current assessment ignores this possibility (due to time constraints), but future assessments
should examine the possibility that the growth rate is a function of cohort size.
The 1996 year class is the highest in the time series and comprises a large component of the biomass in
future projections. However, because of the properties of the modeling, this estimate is the least certain.
Additional data collected over the next few years will reduce this uncertainty.


6.     IMPLICATIONS FOR MANAGEMENT

There were continued improvements in the assessment of blue warehou during 1999. The assessment was
based on an ‗integrated analysis‘ approach which included information on catches, discard rates, catch
rates, and the length/age of discards and landed catch. This approach is more flexible that the fleet-
disaggregated Virtual Population Analysis used in the 1998 assessment. The current assessment uses
length and age data separately, accounts for errors in ageing, and datasets with low sample sizes need not
be included, unlike the VPA. The analysis is based on four fleets (―western trawl‖, ―eastern trawl‖, ―non-
trawl‖ and the Tasmanian meshnet fishery).
For the eastern trawl fleet, standardised CPUE initially increases to a peak in 1990 dropping to a lower
level by 1992 and remaining relatively stable from 1994. The trend in CPUE for the western fishery is one
of continuous decline from 1991 to 1996 with an upturn in 1997 and 1998. The age-composition data
suggest that this is due to a strong year class entering the fishery and growing into its second and third year.
The trawl sector argues that the decline in catch rates can, in part, be attributed to changes to trawl sector
fishing practices and is not solely due to changed abundance. Standardised CPUE for the non-trawl fleet
was variable up to 1990 but has subsequently declined. There was a slight upturn in 1997, followed by a
decline in 1998. Because the non-trawl effort data do not include searching time, the results represent the
minimum decline. The non-trawl sector are very pessimistic about the status of the resource. Catch and
effort data were not available for the Tasmanian fishery. Current catches in this fishery, which are not
included in the TAC, contribute a significant component of total landings and impact projections. In
addition, the recreational catches (not included in the assessment) may be in excess of 150t per year.
Size- and age-composition data are consistent with variable recruitment with a relatively ―strong‖ year class
particularly evident off the east coast during 1997.
The current assessment uses data up to, and including, 1998. The results suggest that the spawner biomass
peaked between 1987 and 1989 dropped markedly to 1994 and has remained relatively stable since. The
spawner biomass in 1998 was about 30% of peak levels. The 1996 cohort (fish aged 3 in 1998) is the
strongest detected to date.
A risk analysis based on 5 and 10-year projections was undertaken (see attached figures). The results were
insensitive to the 1999 catch and the split of this catch between fleets but were very sensitive to the
projection period and the performance indicator chosen. For example, a Commonwealth TAC of 2000t
leads to greater than 50% probability of the biomass being above the minimum biomass between 1991-
1997 for a 5-year projection but a less than 30% probability for a 10-year projection. For the fishing


Blue Warehou                                                                                                  81
mortality indicator, the 5-year projection gives a less than 20% probability of fishing mortality being less
than natural mortality for a 2000t TAC, but a less than 10% probability for the 10-year projection. The
differences between projections reflect the influence of the 1996 cohort as it passes through the fishery.
The results were consistent for a range sensitivity analyses. In summary, the (Commonwealth) TAC
required to achieve a 50% probability of satisfying each performance indicator ranges from less than 1300t
to more than 2000t.

The results suggest that the blue warehou population is influenced strongly by variation in recruitment.
One implication of this is that higher yields can be achieved by conducting annual assessments and
modifying TACs in response to changes in year-class strengths. However, future assessments will need to
consider the implications of shifts in effort between sectors.



7.       RESEARCH NEEDS
Basic data needs and collection
High Priority
 Essential – annual data collection, all sectors and areas through ISMP
        Catch and effort (including analysis using GLM)
        Age- and size-composition of the landed catch
        Discards (magnitude and age- / size-composition)
 Tasmania should be approached to see if annual size- and age-composition information could be
  obtained from the inshore fishery.
 Obtaining estimates of the total recreational catch.

Refinement of analyses and model development
High Priority
Further analyses of catch and effort for the trawl fishery, including:
         Examination of whether catch rates from ―non-target‖ shots could be used to develop an index of
          relative abundance.
         Development of descriptive statistics to characterise the fishery.
         Determination of the impact of the OCS loophole on the catch rates for the ―eastern‖ fleet.
         Analysis of the catch and effort data for ―warehou‖ vessels only (―western‖ fleet).
Further analyses of catch and effort data for non-trawl fishery, including:
      Examination of the statistical properties of the GLM approach to standardizing catch and effort
       data with particular emphasis on the apparent increase in catch rate in the most recent year.
      Implications of increasing shot duration and searching time.
Refinement of data inputs
    Estimation of historical discards
    changes to the fishing year to better reflect the life history of blue warehou and Tasmanian fishery.
    Development of more robust methods to include length frequency data in the assessment.

Further model development, including:
 Evaluating alternative performance indicators and harvest strategies. This work cannot, however,
   commence until the 1999 assessment has been completed. The implications of possible unfished areas
   and regionalization should be considered as part of these evaluations.
 The implications of variable cohort growth and changes to gear selectivity over time, and improved
   maturity ogives.
 Including recreational catches in the assessment.



82                                                                            SEF Species Summary 1999
Specific research needs
Medium Priority
 Age validation.
 Stock structure. A project to examine stock structure through morphology by a post-graduate student
  would be a cost-effective way to further this.
 Correlation with environmental variability. This is an important research area but methods to achieve it
  are unclear.
 Ichthyoplankton surveys – look for evidence of spawning, through presence of eggs or larvae in existing
  collections. This may prove a useful tool for determining whether there are spawning aggregations /
  areas not currently fished. Positive results could be used to plan fishery-independent surveys.

Low priority
 Studies on feeding ecology to provide a better understanding of the biology of the species and potential
  links with environmental variables. It would be a good topic for post-graduate project.

Generic (SEFAG-level) research needs
 SEFAG needs to consider a number of issues relating to Management Objectives and Performance
   Indicators. It is not clear that these are well understood as is the differences between risk assessment
   and harvest strategy evaluation.
 Assessments for blue grenadier, blue warehou and school whiting have all identified considerable
   errors/inconsistencies in SEF1 records. This issue needs to be addressed as a matter of some urgency.

Note: A number of projects have commenced since being identified in last year‘s assessment:
 Evaluating and designing fishery-independent surveys. An ARF-funded desktop study commenced in
   1999.
 Production parameters for similar species. An ARF-funded desktop study of fisheries literature
   commenced in 1999.




Blue Warehou                                                                                            83
                                        1200
 Total catch (tonnes)                                                                               actual TAC
                                                                            approved TAC
                                               800




                                               400




                                                0
                                                       1992   1993   1994       1995       1996     1997     1998
                                                                                Year

Figure I Total annual verified trawl catches of blue warehou calculated from the
         quota monitoring system (SEF2), and actual and approved total allowable
         catches (TAC)




                                               3.5
             standardised catch rate (kg/hr)




                                                 3                                           East

                                               2.5                                           West

                                                 2

                                               1.5

                                                 1

                                               0.5

                                                 0
                                                     85 86 87 88 89 90 91 92 93 94 95 96 97 98 99


Figure II Average annual standardised catch rate for the east and west blue warehou trawl
          fisheries.




84                                                                                                         SEF Species Summary 1999
                           Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) –
                           Blue Warehou



                                         Commonwealth Records                                                         State Records
                     Tr TAC                    Retained Catch                                                          Retained Catch



                                           Commonwealth




                                                                                                                                                        South Australia


                                                                                                                                                                               Estimated total
                                                                                                      SEF non-trawl




                                                                                                                                                                                                 discarded catch
                                                                                                                                                                                                       1




                                                          SEF 2 State
                             Allocated




                                                                                                                                                                                                   Estimated
                                                                                                                        Tasmania
                                                                                    Verified




                                                                                                                                       Victoria
                  Agreed




                                                                                                                                   5




                                                            waters
                                               SEF2




                                                                                                          (SSF)




                                                                                                                                                  NSW
     Year




                                                                          SEF 1




                                                                                                                                                                                     catch
                                                                                               4
                                                                                                                                                                                     3
                                                                                               To
                                                                                               tal



1986                                                                     212       228          228     237            188           ?            ND                              653
1987                                                                     406       586          586     960            360          10            ND                             1916
1988                                                                     544       529          529     774            231          38            ND                             1572
1989                                                                     776       852          852     987            126          72            ND                             2037
1990                                                                     881                    881    1690            367          77            ND                             3015
1991                                                                    1296                   1296    1351            220         110            ND                             2977
1992             2000a 2090a                                             934                    934     701            329          63            ND                             2027
1993             1,000 1,010                   762           217         829                    979     400            274          89            ND                             1742
1994             1,000 1,070                   849           224         941                   1073     282            312         109            ND                             1776
1995             1,000 1,087                   757           194         814                    951     186            138          13            ND                             1288
1996             1,000 1,174                   847             7         724                    854     201            119          10            ND                             1184
1997               700   883                   789             5         662                    794    273c            127           ?            ND                             1333
1998               820 880b                    921            11         820                    933     80c            213           ?            ND                             1226
Commonwealth Records:                                                   State Records:
        1986 - 89 verified catch history                                SEF non-trawl (SSF) Southern Shark Fishery Gill Net
                   warehou totals split by SEF                               1986 - 93 Lakes Entrance LEFCOL
                   logbook proportions of                                    1994 - 96 Lakes Entrance - Vic State Logbook (MAFRI)
                   blue/spotted warehou                                 SEF C/W non-trawl logbook 1997-98
        1990- 92 SEF logbook;                                           State Catches within SEF Area:
        1993 -98 Quota Monitoring System                                     Tasmania DPI Tasmanian logbook
                  (SEF                                                       Victoria Vic State Logbook (MAFRI)
2)
a           combined TAC with Spotted Warehou                           c C/W non-trawl logbook
b       a further 200 t leased from non-trawl sector

1.           Estimated from the SMP                                     Abbreviations:
2.           State location                                                 N/A = Not Applicable
3.           Total of Commonwealth and State                                ND = No Data Available
            records                                                           ? = Available data not received
4.           Total of shaded cells
5.           Excuding southern shark fishery




            Blue Warehou                                                                                                                                                  85
          FLATHEAD
1.         AFMA’S MANAGEMENT OBJECTIVES, STRATEGY AND PERFORMANCE CRITERIA*

          * For SEF management purposes, ‗flathead‘ refers to a group of flathead species
          consisting predominantly of tiger flathead (Neoplatycephalus richardsoni) but including
          sand flathead (Platycephalus bassensis) and, from 1996 onwards, southern or ‗yank‘
          flathead (Platycephalus speculator), bluespot flathead (Platycephalus caeruleopunctatus)
          and gold-spot/toothy flathead (Neoplatycephalus aurimaculatus). Tiger flathead is the only
          species being considered for stock assessment purposes at this stage.

          Objectives
          Ongoing
     1.   To ensure that flathead resources are utilised in a manner consistent with the principles of
          ecologically sustainable development.
          Immediate objective
     2.   To ensure that the biomass of tiger flathead does not significantly decline below its current
          level:
            current jurisdictional boundaries and varying approaches to management by the States and
          Commonwealth need to be reconciled if this objective is to be achieved.
          Ongoing
     3.   To maximise the economic efficiency of the flathead fishery.
     4.   To implement effective and efficient fisheries management on behalf of the
          Commonwealth.

         Strategies
     The above objectives will be achieved by:

     1.   setting a TAC for the Commonwealth managed portion of the fishery that:
               maintains the standardised catch per unit effort (CPUE) in the fishery above its lowest
               annual average from 1986 to 1994. (Objectives 1 & 2)
               [Note that the TAC currently only applies to the trawl sector of the fishery within the
               SEF, excluding the Southern Remote Zone]

     2.   managing all sectors of the flathead fishery in a complementary manner.
          (objectives 1, 2 & 4)

     3.   prioritising flathead research in relation to other SEF species:
              SETMAC has given a medium research priority rating to tiger flathead. (objectives 1,
              2, 3, & 4)

     4.   data collection:
           (i) obtaining estimates of catch and catch rates, and monitoring shifts in effort and changes
                in fishing practices.
           (ii) monitoring length distributions in commercial catches and undertaking ageing as
                required.
           (iii) obtaining estimates of the spawning biomass of tiger flathead at the onset of
                significant commercial fishing (date to be determined) and;
           (iv) obtaining estimates of the current spawning biomass of tiger flathead through catch-at-
                age analyses using existing catch/effort, age composition and length composition
                information. These analyses also to be used to determine future data requirements and
                sampling strategies. (Objectives 1 & 2)

     5.   undertaking economic research on the fishery to calculate GVP and monitoring market
          prices for flathead. (Objective 3)

          Performance indicators
     1.   That the current annual standardised CPUE for the fishery is above its lowest annual
          average from 1986 to 1994. (Strategy 1)


          86                                                                         SEF Species Summary 1999
2.   That all sectors of the fishery (Commonwealth and State) are being managed in a
     complementary manner. (Strategy 2)

3.   Data relevant to the annual assessment of tiger flathead have been collected, analysed and
     considered by SEFAG. (Strategies 1, 3, 4 & 5)

4.   The actual trawl/Danish seine catch relative to the TAC (Strategy 1)

2.   STOCK STRUCTURE AND LIFE HISTORY
     The stock structure of tiger flathead is still poorly understood. There is little evidence of
     morphological variation across the species distribution range despite observed regional
     differences in growth and the timing of reproduction. No stock identification studies have
     been carried out using genetic or other techniques and for management purposes a single
     continuous stock has been assumed throughout all zones of the SEF.
     Tiger flathead are endemic to Australia and are found on sandy or muddy substrates in
     continental shelf and upper slope waters from about Coffs Harbour in northern NSW
     through Bass Strait and around Tasmania to south-east South Australia. Most of the
     Australian commercial catch comes from depths between 50 m and 200 m. Except for the
     spawning season, older larger fish are more commonly caught in outer shelf waters (65 m -
     200 m) whereas juveniles and smaller adults are mainly found in inner shelf waters.
     The species has a protracted spawning season over spring, summer and autumn months,
     with some suggestion that adults move into inner shelf waters to spawn and then disperse
     back into deeper waters. Apart from the general inshore movement of adult fish during the
     spawning season, there is little evidence of any substantial migrations of tiger flathead.
     Little is known of the post-larval and early juvenile stages of tiger flathead. It has been
     assumed that these stages occur in shallow coastal waters inshore of the main SEF fishing
     grounds. However, systematic sampling of Tasmanian coastal waters has failed to find
     them. Juveniles eat mainly crustaceans, whereas adults feed mainly on small fish such as
     silversides and cardinal fish. Predators of juvenile tiger flathead include John dory and
     larger tiger flathead.

     Female tiger flathead grow faster and live longer than males. Maximum recorded ages are
     8-10 years for males and 12 years for females which may reach up to 65 cm LCF. Virtually
     all fish above 50 cm LCF are female. Initial growth is rapid, with a mean length of about 20
     cm LCF being attained after one year. Age at first sexual maturity is 3 - 5 years; equivalent
     to fork lengths of about 25-30 cm for males and about 30-35 cm for females, depending on
     the region

3.   THE FISHERY
     Current situation
     The 1998 SEF2 landed weight of flathead was 2664 t (2543 t in Commonwealth waters and
     121 t in State waters), which was 66% of the actual TAC of 4,009 t. It represents a 0.05%
     decrease in landings compared to 1997 (2677 t). The 1999 agreed TAC was again 3,500 t,
     with the actual TAC being 3,966 t.
     The flathead TAC includes tiger flathead and other flathead species, but the former makes
     up the bulk of the catch. There are currently few quantitative estimates of the species
     composition of SEF flathead catches. On-board examination of Danish seine flathead
     catches taken in eastern and central Bass Strait during 1994 indicate that in depths of
     >50m, tiger flathead constitute virtually all (99%) of the flathead catch with incidental
     catches of sand flathead. Tiger flathead was still the dominant species (78%) in Danish
     seine catches from <50m, but these catches also included significant proportions of sand
     flathead (9%), southern/yank flathead (7%) and gold spot/toothy flathead (6%).
     The contribution of Danish seine vessels to total SEF flathead landings declined from
     around 50% in the late 1980s to less than 30% in the mid 1990s. This trend has reversed in
     1997 and 1998 with Danish seine catches comprising about 45% of the flathead catch. On


     Flathead                                                                                        87
     average, the SEF Danish seine catch of tiger flathead is caught in Eastern Zone B (51%)
     and the Bass Strait Zone (44%). In contrast, only 6% of trawl catches have come from the
     SEF Bass Strait Zone, most comes from Eastern Zone A (43%) or Eastern Zone B (45%).
     Trawl catches in Eastern Zone B declined by over 40% from 1990 to 1994, but have since
     recovered and reached their highest recorded level of 883 t in 1997 and were 839 t in 1998.
     There is little seasonal variation in trawl catches or catch rates from the two main areas for trawled
     flathead; Eastern Zones A and B. By contrast, the trawl catch and catch rate data for the Bass Strait
     and Eastern Tasmania Zones indicate smaller, summer/autumn target fisheries in these areas. Seasonal
     patterns in Danish seine catches and catch rates for tiger flathead are difficult to discern because of the
     confounding effects of greater inter-annual variability in the data. Nevertheless, the data indicate that
     tiger flathead are targeted and caught in significant quantities throughout the year in Eastern Zone B,
     but in most years the best catch rates are obtained during summer and autumn. Seine catches and catch
     rates in the Bass Strait Zone are consistently highest in summer reflecting both seasonal fluctuations in
     flathead abundance and seasonal switches between flathead and school whiting as the preferred target
     species.

     Industry delegates at the November 1995 flathead stock assessment workshop noted that, in
     general, the abundance of tiger flathead stocks has been stable in recent years, and that the
     recent declines in SEF catches and catch rates are probably attributable to several factors
     other than declining stock abundance. These comments were reiterated during 1996 and
     1997 port visits. These factors include:- (i) increased grading of catches and discarding of
     smaller, low-priced flathead, particularly by some trawl operators with quota limitations
     towards the end of the year; (ii) increased trawl shots over hard bottom using rubber or
     bobbin gear, leading to more shots containing flathead as by-catch which depressed
     flathead catch rates; (iii) lower than average occurrence in 1994 and 1995 of warm water
     eddies normally associated with good catches of flathead; and (iv) poor weather over the
     last few years, which restricted target flathead catches by Danish seiners in outer shelf
     waters and increased the proportion of flathead taken as a by-catch of shallow water
     whiting fishing. Some of these factors were examined in more detail in the 1996
     assessment.

     Industry also commented that failure to catch the 1993 or 1994 flathead TAC‘s was more a
     consequence of fishing activities (eg. Danish seine operators preferring to target whiting)
     and inappropriate quota distribution, than availability of flathead stocks. It was claimed
     that the SEF quota allocation process resulted in flathead quota being allocated to a number
     of deepwater trawl vessels which do not target flathead quota species and that total SEF
     flathead catches are unlikely to approach the current TAC until this unused quota has been
     acquired by operators who target flathead in shelf waters.

     It is not possible with current catch data to break down the total flathead catch value by
     species. In 1998, average prices for small and large tiger flathead at the Melbourne Fish
     Market were $1.00/kg and $2.20/kg respectively. This compares with $1.53/kg and
     $2.55/kg respectively in 1997. At the same market, the average price of deepwater flathead
     (from the GAB) was $2.37/kg in 1998 ($2.37/kg in 1997). At the Sydney Fish Market, tiger
     flathead prices ranged from $1.03/kg for small fish to $2.67/kg for extra large fish in 1998
     ($1.54/kg for small fish and $3.78/kg for extra large in 1997). Prices for sand flathead on
     the Sydney market ranged from $0.90/kg for small fish to $1.86/kg for extra large fish. The
     NSW industry claims that the costs of leasing quota and processing, transporting and
     marketing charges make it uneconomical to sell smaller tiger flathead in the Sydney
     Market. Since the introduction of quotas in 1992, much of the retained catch of small tiger
     flathead from southern NSW ports has reportedly been sent to Melbourne rather than to
     Sydney. The 13 inch (TL) minimum size limit imposed by NSW obviously influences this
     marketing decision.


4.   PREVIOUS ASSESSMENTS
     Maximum sustainable yields for NSW stocks of tiger flathead were estimated using surplus
     production methods and fishery data. MSY estimates were also estimated for tiger flathead
     in eastern Bass Strait. It was suggested that, as there was little overlap in the geographical

     88                                                                          SEF Species Summary 1999
areas on which these MSY estimates were based and preliminary tagging data indicated low
rates of movement and mixing by tiger flathead, then the two MSY estimates could be
pooled to give a sustainable yield of about 2500 tonnes for the SEF as a whole.
A stock reduction method and a time series (1928-1934) of declining commercial fishery
catch rates early in the development of the tiger flathead fishery was used to obtain an
estimate of the unexploited biomass existing in the late 1920s. The only direct estimate of
tiger flathead biomass is that resulting from a 1982-85 trawl survey of eastern Bass Strait
waters, which yielded a standing crop estimate of about 6900 t for this area; which covers
probably less than half the total tiger flathead distribution area.
In the 1993 assessment, tiger flathead age and length data were examined together with
catch and effort data up to 1992. The Stock Assessment Group considered catches and
catch rates in the SEF to have been comparatively stable between 1986 and 1992. They
also observed similar coefficients of total mortality (Z) derived from the age structure of
catches in 1982-83 and in 1991-92, leading to the conclusion that tiger flathead stocks off
NSW and eastern Bass Strait were stable. The Group also noted that tiger flathead catches
from south-east Tasmanian waters contained higher proportions of larger, older fish than
those from eastern Bass Strait. This indicated that tiger flathead resources off Tasmania
were more lightly fished than those in the main fishing areas to the north, although the
possibility that Tasmanian tiger flathead were a separate stock with different population
characteristics could not be discounted.
The 1994 SEFAG assessment included examination of catch/effort data, size composition data and age
composition data up to 1993. Information from the on-board Scientific Monitoring Program (SMP) on
discarding of tiger flathead was also available. It was noted that Danish seine catches contained
smaller fish on average than trawl catches, both in eastern Bass Strait and off eastern Tasmania. The
SEFAG observed a slight decline in tiger flathead catch rates in the Eastern B and Bass Strait zones of
the SEF, but not in Eastern Zone A. However, the age and size compositions of tiger flathead catches
from eastern Bass Strait were similar between 1991 and 1993, leading the SEFAG to again conclude
that stocks in eastern Bass Strait and southern NSW were stable.

Most recent assessment
The most recent formal assessment was undertaken in 1995/96 during a SEFAG workshop
held at MAFRI, Queenscliff in November 1995. Data used in the assessment included the
SEF catch/effort data to 1995, port-based size composition data, SMP observations of size
composition and discarding rates for 1993 to 1995 and updated (1994 & 1995) age-length
keys and length-at-age tables. Preliminary research trawl survey information on the
distribution, relative abundance and population characteristics of tiger flathead in eastern
Tasmanian waters was made available. The main assessment approach was the examination
of key fishery indicators such as catch/effort data and the size and age composition of
catches. Details of the stock assessment are in the 1996 Stock Assessment Report which is
summarised below.


Size composition
On-board measurements of catches taken by NSW-based trawlers produced size
distributions for the retained portion of the catch which matched reasonably well with port-
based measurements of landed catches. The on-board measurements revealed that trawlers
were catching tiger flathead as small as 14 cm LCF, but most flathead between 14 and 33
cm LCF were being discarded. In Lakes Entrance, port-based and on-board monitoring
again showed that tiger flathead taken by Danish seiners are generally smaller than those
taken by trawlers. Not being restricted by the NSW 13í minimum size limit, seine
operators in Lakes Entrance retained smaller flathead for sale. Some size composition data
for eastern Tasmanian tiger flathead were available from research trawl surveys in 1993
and 1994 and from measurement of commercial catches between 1972 and 1992. The most
obvious feature of the Tasmanian fishery is the significantly higher proportion of larger,
older fish which is not seen in commercial catches elsewhere.




Flathead                                                                                                  89
     SMP observations of trawl vessels operating for up to three days per trip out of Eden,
     Ulladulla and Newcastle/Tuncurry (north of Sydney) showed that tiger flathead catches,
     catch rates and absolute amounts of discards increased from north to south along the NSW
     coast. Levels of discarding of tiger flathead by Victorian-based Danish seiners and trawlers
     are generally lower than those by southern NSW trawlers.
     Age composition
     Ageing data from around 5000 fish caught from different zones of the fishery during 1991 - 1995 were
     examined. There was little difference in mean length-at-age for fish from Eastern Zone A, Eastern Zone
     B or Eastern Tasmania and, in all cases, the differences between males and females was greater than
     the differences between areas. The retained component of trawled catches from Eastern Zones A and B
     was dominated by 4 to 6 years old fish and the maximum recorded individual age was 12 years.
     Eastern Tasmanian catches contained a higher proportion of large, old fish and had a maximum
     recorded age of 17 years. Examination of the 1990s age structure of retained trawl catches of tiger
     flathead in Eastern Zones A and B revealed that the proportion of total population numbers represented
     by adult fish 7 years old or more, had been steadily falling from 26.4% in 1991 to 8.8% in 1994. This
     trend was also reflected in the mean age of the population, which had declined from 5.73 years in 1991
     to 5.00 years in 1994.
     Mortality
     The instantaneous coefficient of total mortality (Z) was estimated to be about 1.0 from
     catch curve analyses from Eastern A and B. The age structure of the lightly exploited
     Tasmanian fishery was used to provide the ―best‖ estimate of natural mortality (M), which
     ranged from 0.27 to 0.46 depending on the sex. This suggested that fishing mortality (F) in
     Zones A and B was relatively high.

     Uncertainty
     Inadequate information on the following confounded the interpretation of catch rate and
     size/age composition data; changes in fishing practices and/or target preferences; inshore
     redistribution of trawl effort; fluctuations in the levels of discarding; and the species
     composition of flathead catches.



5.   THE 1999 UPDATE
     There was no formal assessment of tiger flathead undertaken during 1999. However, 1998
     logbook and ISMP data were incorporated into this update.
      Catch and effort
     The 1998 SEF2 landed weight of flathead was 2664 t (2543 t in Commonwealth waters and
     121 t in State waters), which was 66% of the actual TAC of 4,009 t. It represents a .05%
     decrease in landings compared to 1997 (2677 t). The high trawl catches in Eastern Zone B
     continued in 1998 (839 t) although they were slightly lower than the record catch in the
     previous year (882 t). Trawl catches in Eastern Zone A increased by 69 t to 416 t. Danish
     seine catches of flathead in Bass Strait achieved a record low (161 t) in 1998, but catches in
     Eastern Zone B have continued to increase over the last five years and now comprise
     around 80% of the Danish seine catch. Danish seine catches continued to account for
     around 45% of the total tiger flathead catch. The 1999 agreed TAC was again 3,500 t, with
     the actual TAC being 3,966 t.
     Between 1991 and 1995, landings of flathead by State-licensed vessels in Tasmania and
     Victoria were fairly constant at about 140-160 tonnes per annum. They increased to 200 t
     in 1996 (69 t Tas and 128 t Vic) and dropped to 186 t in 1997 (62 t and 124 t respectively).
     State catches dropped significantly in 1998 to 105 t (51 t Tas and 54 t Vic) largely
     resulting from the decrease in Victorian catches. This may be related to the increased
     number of Victorian fishers submitting commonwealth rather than state logbooks.
     Recorded flathead catches north of Barrenjoey Point in NSW ranged between 120 and 220
     t over 1991-95.
     The recent decline in mean unstandardised catch rates (i.e. data based only on shots
     containing flathead) was turned around in 1997 with considerable increases in the catch

     90                                                                         SEF Species Summary 1999
     rates of both trawlers (40 kg/hr)and Danish seiners (132 kg/shot) compared to 1996 (35
     kg/hr and 102 kg/shot respectively). During 1998, the mean unstandardised catch rates of
     trawlers increased to 43 kg/hr, but the catch rate of Danish seine vessels decreased to 109
     kg/shot.

     Size composition
     The length frequencies of flathead landed to the east of Bass Strait have remained stable
     since 1993. Fish generally range between 25 and 50 cm LCF with a mode of around 30 cm
     in Eastern Zone A and up to 40 cm in Eastern Tasmania. Similar to previous years, on-
     board measurements by ISMP scientists during 1998 revealed that trawlers catch tiger
     flathead as small as 14 cm, but because of the 13 inch minimum size limit in NSW, most
     flathead between 14 and 33 cm caught in Eastern Zone A and B were discarded. Tiger
     flathead taken by Danish seiners in Bass Strait were are generally smaller than those taken
     by trawlers and fish as small as 27 cm may be retained, as they are not restricted by the
     NSW minimum size limit. Catches of tiger flathead in Eastern Tasmania had a
     significantly higher proportion of larger fish, ranging up to 65 cm with a mode around 40
     cm LCF.
     Discard rates
     In general, levels of discarding of tiger flathead by Victorian-based Danish seiners and
     trawlers are lower than those by southern NSW trawlers. This was again the case during
     1998, with overall discard rates around 10%, but ranging between 21% in NSW ports and
     9% in Victorian trawlers and seiners. This is largely influenced by the NSW size limit.
     Based on the ISMP data, these discard rates equate to around 275 t of spotted warehou
     discarded across the SEF during 1998. Combined with the SEF2 landings of 2664 t, the
     total catch of tiger flathead (including discards) in 1998 was around 2939 t, which was 73%
     of the allocated TAC of 4009t.
     Port visits
     Port visits during April 1999 were held in Tasmania and western Bass Strait and no
     comments relevant to flathead catches were noted. During April 1998 port visits on the east
     coast, however, fishers stated that increased landings of flathead in Lakes Entrance were
     because of a transfer of fishing effort from whiting. Generally flathead are most abundant
     during the summer period, but most NSW ports reported a scarcity of flathead during the
     97/98 summer. In contrast, there were abundant large flathead caught off the east coast of
     Tasmania during summer. The presence of warmer waters off the NSW coast was
     highlighted as a possible reason for increased catches further south. Targeting practices
     were also influenced by the market and fishers reported less interest in smaller species such
     as flathead. Previously, some concern has expressed that deepwater flathead landings from
     the GAB were affecting market prices and several operators thought that SEF deepwater
     flathead should be included in the TAC.
     Prices
     In 1998, the gross value of recorded landings of tiger flathead was estimated to be about
     $4.37 million. The average price on the Sydney fish market was $2.12/kg, compared to
     $1.74 on the Melbourne fish market.

6.   IMPLICATIONS FOR MANAGEMENT
     Catch rates for both trawl and Danish seine declined from 1989 to 1994, particularly in
     Eastern Sector B. There was also a decrease in the proportion of larger, older tiger flathead
     (7 years or more) in eastern Bass Strait and southern NSW catches. Estimates of fishing
     mortality obtained from the age composition of catches were relatively high. These results
     were consistent with the hypothesis that tiger flathead abundance in the eastern Bass Strait
     area had been declining, both in number and biomass, from the late 1980s.

     Catch rates of both trawlers and Danish seiners have improved since 1995 and continued to
     improve in 1998. The allocated SEF flathead TACs since 1994 have been substantially
     higher than any annual total catch in the recent history of the fishery, and are higher than
     previous estimates of sustainable yield. As such, the fishery must be closely monitored.


     Flathead                                                                                        91
     Although discarding rates dropped during 1997, it is consists of mainly small tiger flathead.
     This problem is highest in NSW where a 13 inch minimum size limit is enforced. This size
     limit was introduced primarily as a marketing tool. The discrepancy between size limits in
     NSW and Victoria needs to be addressed.



7.   RESEARCH NEEDS
     General
      i)    Flathead are one of several SEF species for which significant discarding of small fish
            occurs and should be included in a wide ranging study of mesh and gear selectivities
            in the SEF.
      ii)   More detailed examination of logbook catch/effort data by individual vessel is
            needed; to gain more insight into changes in fishing practices; to distinguish target
            catch from by-catch; etc. Spatial and temporal analyses of recent and historic catch
            and effort data should also be undertaken
      iii) More detailed information on the relationships between quota holdings and fishing
           behaviour and the failure to catch more than half the flathead TAC.
      iv)   A better understanding of species interactions, environment factors that influence
            flathead distribution and abundance, fleet dynamics, and net selectivity/gear
            configuration - particularly for trawlers.


     Specific
      vi)   Detailed investigation of the fishing practices of the top flathead-catching vessels in
            Eastern Zone B.
      vii) Determination of stock structure and rates of movement.
      viii) Determination of the location and habitat requirements of small juvenile (<10cm)
            tiger flathead.
      ix)   Determine the compatibility of recent and historic ageing and length frequency data
            for tiger flathead and the utility of these data in constructing or tuning an age-
            structured stock assessment model.
      x)    Investigation of alternative approaches for the development of a recruitment index for
            tiger flathead (eg. Danish seine by-catches, industry-based annual surveys, research
            surveys).




                                    4500
                                                                                                      actual TAC
             Total catch (tonnes)




                                                                                                      approved TAC
                                    3000



                                    1500



                                      0
                                           1992   1993   1994   1995   1996        1997       1998

                                                                Year

     92                                                                           SEF Species Summary 1999
Figure I Total annual verified trawl and Danish seine catches of tiger flathead
         calculated from the quota monitoring system (SEF2), and actual and
         approved total allowable catches (TAC)



                          60                                                                             300




                                                                              av. catch rate (kg/shot)
                          50                                                                             250
 av. catch rate (kg/hr)




                          40                                                                             200

                          30                                                                             150

                          20                                                                             100

                          10                                                                             50
                          0                                                                               0
                               85 86 87 88 89 90 91 92 93 94 95 96 97 98 99                                    85 86 87 88 89 90 91 92 93 94 95 96 97 98 99


                                                (a)                                                                               (b)
Figure II (a) Average annual unstandardised trawl catch rate of flathead
                                   (b) Average annual unstandardised Danish seine catch rate of flathead




Flathead                                                                                                                                             93
        Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) –
        Flathead

                                   Commonwealth Records                                            State Records
                 TAC                        Retained Catch                                        Retained Catch




                                                                                                                                            discarded catch1
                                    Commonwealth




                                                                                                                          Estimated total
                                                   SEF 2 State




                                                                                                                                               Estimated
                       Allocated




                                                     Waters
        Agreed




                                                                                 Total4




                                                                                                                              catch3
                                                                 SEF 1


                                                                         Other
                                       SEF2




                                                                                           NSW
 Year




                                                                                                            Tas


                                                                                                                   S.A.
                                                                                                    Vic
1919                                                                                       1250
1920                                                                                       2300
1921                                                                                       N.D.
1922                                                                                       2100
1923                                                                                       1200
1924                                                                                       N.D.
1925                                                                                       N.D.
1926                                                                                       N.D.
1927                                                                                       N.D.
1928                                                                                       5600
1929                                                                                       5900
1930                                                                                       4800
1931                                                                                       4200
1932                                                                                       3600
1933                                                                                       2900
1934                                                                                       2700
1935                                                                                       N.D.
1936                                                                                       N.D.
1937                                                                                       N.D.
1938                                                                                       3400
1939                                                                                       3300
1940                                                                                       2700
1941                                                                                       1100
1942                                                                                        420
1943                                                                                        360
1944                                                                                        550
1945                                                                                       2600
1946                                                                                       2400
1947                                                                                      why
1948                                                                                      this
1949                                                                                      gap?
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
                                   Commonwealth Records                                           State Records
        94                                                                                                SEF Species Summary 1999
     Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) –
     Flathead
                                         Commonwealth Records                                                State Records
                       TAC                        Retained Catch                                            Retained Catch




                                                                                                                                                                  discarded catch1
                                          Commonwealth




                                                                                                                                                Estimated total
                                                         SEF 2 State




                                                                                                                                                                     Estimated
                             Allocated




                                                           Waters
              Agreed




                                                                                        Total4




                                                                                                                                                    catch3
                                                                       SEF 1


                                                                               Other
                                             SEF2




                                                                                                      NSW
     Year




                                                                                                                          Tas


                                                                                                                                    S.A.
                                                                                                                Vic
 1963                                                                                               why
 1964                                                                                               this
 1965                                                                                               gap?
 1966
 1967
 1968
 1969
 1970
 1971
 1972
 1973
 1974
 1975
 1976
 1977
 1978
 1979
 1980
 1981
 1982
                                                          SEF not Established
 1983
 1984                                                                          1593    1593                                                        1593
 1985                                                                          1965    1965                                                        1965
 1986                                                                  2075    2097    2097                                                        2097
 1987                                                                  2490    3194    3194      ?                84                               3278
 1988                                                                  2494    2961    2961      ?               127      77                       3165
 1989                                                                  2609    2928    2928      ?               119      81                       3128
 1990                                                                  2037            2037      ?               107     153                       2297
 1991                                                                  2226            2226      ?                99     126                       2451
 1992 3000 3027                              2075         676          2375            2750      ?               147     130                       3027
 1993 3000 3129                              1474         686          1868            2160      ?               132     121                       2413
 1994 3500 3822                              1497         455          1710            1950      ?               150     121                       2082
 1995 3500 4195                              1712         321          1800            2033      ?               102      71                       2206
 1996 3500 4300                              1893         221          1875            2114      ?               133      51                       2298
 1997 3500 4134                              2507         170          2355            2677      ?               128      62                       2867
 1998 3500 4009                              2543         121          2305            2664      ?                 ?      54
Commonwealth records:                                                                    State records:
       1984 - 1989 verified catch history                                                        1919 - 1946 NSW landings
       1990 - 1991 SEF Logbook                                                                   1947 - 1969 NSW & Vic landings
       1992 - 1998 SEO3, SEF1 & 2 (1993 onwards includes                                         1970 - 1983 NSW & Vic landings (rounded to 50t)
           catch recorded in State waters within the SEF area)                                   1988 - 1998 Tas Danish Seine - Tasmanian DPI
                                                                                                 1987 - 1997 Vic Inshore trawl - Vic state logbook
                                                                                                             (MAFRI).
1.    Estimated from the SMP                                                                        Abbreviations:
2.    State location                                                                                     N/A = Not Applicable
3     Estimated by totaling Commonwealth and State records                                               ND = No Data Available
4     Total of shaded cells                                                                               ? = Available data not received
     Flathead                                                                                                                                    95
 GEMFISH, EASTERN


1.    AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE
      INDICATORS

    Objectives
    On-going
 1. To ensure that the eastern gemfish resource is utilised in a manner consistent with the principles of
    ecologically sustainable development.

      Immediate objectives
 2.   To rebuild the stock to a level at which targeted commercial fishing may recommence.

 3.   To implement effective and efficient fisheries management on behalf of the Commonwealth.


      Strategies

      The rebuilding objective is to be achieved by the principle strategy of :

 1. Setting a TAC of zero for the Commonwealth managed trawl sector of the fishery until the spawning
    biomass has a 50 per cent probability of exceeding 40 per cent of the 1979 biomass level.


 2. STOCK STRUCTURE AND LIFE HISTORY

 Gemfish are caught along the edge of the continental shelf of southern Australia and New Zealand. The
 eastern gemfish is caught from eastern Tasmania to northern NSW. A genetically distinct stock of (western)
 gemfish occurs to the west of Tasmania. Eastern gemfish mature at 3-6 years of age and have been aged to
 17 years. Mature fish migrate north along the NSW shelf break during winter spawning in large
 aggregations.

 3. THE FISHERY

 Eastern gemfish are mainly caught by demersal board trawlers targeting the winter spawning migration in
 depths of about 400m. The trawl fishery developed in the late 1960s and early 1970s, and recorded catches
 peaked at around 5,000t in 1980. Gemfish are also caught by droplining and gillnet methods.

 4. PREVIOUS ASSESSMENTS

 The Demersal and Pelagic Fisheries Research Group (DPFRG) initiated a series of cohort analyses
 beginning in 1988 (Allen 1989, 1992). In 1994, several other catch-at-age methods were applied by various
 researchers. These are described in the annual Stock Assessment Reports prepared by SEFAG (Chesson
 1995). Although the results of these different analyses differ in their details, they show a similar overall
 pattern, namely a decline in adult biomass in the early 1980s, and a marked drop in recruitment of cohorts
 spawned in the late 1980s.

 In response to a decline in catch rates and mean fish size in the early 1980s, a 3000t TAC was introduced
 for eastern gemfish in 1988. Taking into account the results of the subsequent cohort analyses, the TAC
 was progressively reduced to zero in 1993. The TAC has remained at zero for 1994, 1995 and 1996, with
 trip limits to allow for unavoidable bycatch.

 In 1996, a consensus emerged among modellers of eastern gemfish that the model described in Punt (1996)
 was the most appropriate and flexible approach for future analysis (Chesson 1996). There was also strong
 support for the need to gain new catch rate information from an experimental fishing survey, since the


 96                                                                               SEF Species Summary 1999
imposition of the zero TAC in 1993 had effectively ended the existing catch rate series.

An eastern gemfish workshop in April 1996 confirmed the desirability of a survey and proposed the
formation of the Eastern Gemfish Assessment Group (EGAG). EGAG developed both the trawl survey, and
a new and more comprehensive assessment of the status of the resource, together with a preliminary
evaluation of possible future harvest options. The EGAG assessment, summarised in the March 1997
report, indicated a high probability that the stock had recovered to above the reference point of 40% of the
1979 biomass. The report also emphasised the variability in recruitment to the stock, and the possible
benefits of a flexible approach to the setting of future TACs.

The South East Trawl Management Advisory Committee (SETMAC) recommended the setting of bycatch
trip limits for the fishery for the period 1 January to 30 April 1997, and delayed recommending a 1997
TAC until the 1996 assessment report was available. On the basis of that report, and of further evaluation of
harvest options during the meeting of the TAC sub-committee, a recommendation was made for a 1200t
total catch for 1997, of which 1000t would be an allocated TAC for the SEF trawl sector. This
recommendation also noted that there was a strong possibility that the catch would be reduced substantially
in 1998 (back to previous by-catch levels) due to evidence of further weak year classes since 1990. Plans
were also developed for a further trawl survey for 1997. The recommended management arrangements for
1997 were endorsed by SETMAC, the Non-trawl Consultative Committee, the AFMA Board, and, after
some further evaluation by Environment Australia, by the Minister for Environment.

A TAC of 1000 t was set for the trawl component of the SEF (south of Barrenjoey) during the 1997 winter
season, and the non-trawl and State components of the fishery were subject to trip limits. Trawl catches
amounted to 310 t during the 'forward run‖. Although the geographic pattern of catches was similar to that
expected during an 'average' gemfish season, catch rates were uniformly low across the fishery, with higher
catch rates (> 500 kg / hr) occurring sporadically. Analysis of standardised catch rates from SEF2 data
(using the selection rules previously developed to define 'target' fishing for gemfish) showed a substantial
reduction in CPUE for the 1997 season (643 kg / std day) compared with the result obtained from the 1996
survey (1371 kg / std day).

5. 1998 ASSESSMENT

The assessment of the status of the stock of eastern gemfish has been developed as a collaborative exercise
by EGAG. All the data inputs to the assessment have been reviewed, and EGAG has reviewed the
assumptions underlying the assessment, focusing on major uncertainties and alternative hypotheses about
the dynamics of the resource.

The data used in the assessment include estimates of historical catches, catch rates in the winter fishery, the
age and size composition of the catches, the proportion of the winter catch which is female, and the results
of the 1996 and 1997 surveys. Two historical catch series (A and B) were used in the analyses, reflecting
uncertainty in catches particularly during the developmental phase of the fishery. The data used in the 1998
assessment are fully described in Punt et al. (1998).

The model used in the assessment was developed specifically for the gemfish fishery, and incorporates a
number of aspects of the stock and fishery suggested by members of EGAG. It is age- and sex-structured
and takes account of both the summer and the winter fisheries. Values for the parameters of the model are
estimated by fitting it to the data sources listed under ‗data inputs‘ above. Maximum likelihood and
Bayesian estimation frameworks were used. The maximum likelihood method estimates a single best fit to
the data given the model and data specifications, and was used to investigate the impact of a wide range of
changes to the specifications (both data and model structure) of the basic assessment. The Bayesian method
takes greater account of uncertainty about the fit of the model to the data, and therefore provides a more
suitable basis for evaluating the outcomes and risks associated with future possible harvest strategies. Full
technical specifications of the assessment are provided by Punt (1998).

The 1998 fishing season and survey

An allocated by-catch TAC of 300t was set for the trawl component of the SEF (south of Barrenjoey)
during the 1998 winter season, and the non-trawl and State components of the fishery were subject to trip


Eastern Gemfish                                                                                             97
limits. One hundred tonnes was set aside for research quota to support the survey. Winter trawl catches
were approximately 156t of which 30t were research quota catches from two of the survey vessels. There
were reports of 15t being discarded early in the winter season by boats with very small quota allocations.
Estimated NSW dropline catches (30t) were half those of the previous season while Commonwealth non-
trawl catches were only 3t. All catch figures for 1998 are preliminary.

Standardised catch rates were obtained from three survey vessels. The total catch for the three survey
vessels was 56t. The season for the catch rate analysis was defined as in previous years. The standardised
catch rate for 1998 was 926 kg / std day, an increase on the 1997 level (643 kg / std day) but lower than the
1996 level (1371 kg / std day).

On-board and market measuring showed similar patterns to 1996 and 1997 in the length frequency
distributions of adult gemfish. The adult mode principally represents the strong 1990 cohort that has now
reached 80-90cm. The impact of this cohort is dropping due to natural mortality. Length data collected
from survey catches found a strong mode at 45cm suggesting that the 1996 cohort may be a strong one.
Fishers have also noted a widespread abundance of juvenile gemfish in their by-catch over the last 18
months. Industry members believe that, similarly to blue grenadier and blue warehou, this increased
incidence of bycatch indicates that the 1996 cohort is extremely abundant.

The bycatch of smaller fish during the winter season does not affect the quantitative assessment. However
the 1996 cohort is also evident in the summer fishery and these fish are taken into account in the
assessment. This year‘s assessment does indicate that recruitment for the 1996 cohort is above the level
expected. However it will take several years before the strength of the 1996 cohort is well estimated.

Fishing patterns in 1998

The assessment uses catch / std day as the primary index of gemfish abundance. But it is increasingly
apparent that a range of factors affect daily landings besides gemfish abundance.

In 1998 the survey vessels were placed on a daily charter, as in 1996, but in contrast to 1997 when they
continued fishing commercially. Consequently the survey vessels each completed around 1.5 gemfish shots
per day, a similar level to 1996, but an increase from 1997 when 3 survey vessels only completed about 0.5
gemfish shots per day. This variation in fishing pattern between years apparently affects the catch rate
trend estimated by EGAG and needs to be analysed more closely by EGAG.

In 1998 the principal catches of adult gemfish were associated with two distinct periods and locations.
During the last week of June, vessels operating south of Eden operated around an aggregation of gemfish
near the Horseshoe (approx. 38S). This aggregation was not surveyed.

Within the survey area (Montague Island - Barrenjoey Pt.; 36S-34S) an aggregation of gemfish apparently
formed on the Ulladulla grounds during the first week of July and then slowly tracked north along the edge
of the shelf. The survey vessels recorded catch rates above 1,000kg/shot from 13 - 19 July. In this time the
centre of the aggregation tracked steadily north from 35.5S to 34.5S. Surveyed catch rates declined
abruptly on 20 July when the aggregation of gemfish moved north past Sydney and beyond the last of the
main SEF trawl grounds south of Barrenjoey Point. Sporadic by-catches of gemfish occurred on the deep
(600m) prawn grounds north of Sydney through until mid-August suggesting that gemfish aggregations
continued north of Barrenjoey for some time after the survey boats were constrained from further fishing.

Although it was expected that Research Permits would be granted to allow the survey vessels to continue
surveying the gemfish aggregation north of Barrenjoey, these arrangements fell through during the season.
The minutes of the 11th meeting of EGAG record the very strong industry concerns about this issue.
Industry members stressed that until 1989, gemfish fishing always continued to the north of Barrenjoey, and
that, to be comparable with historical trends, surveys should follow the aggregations over the historical
range of the fishery. In their experience the highest catch rates of the season are taken at the height of
spawning which is generally north of Barrenjoey. Industry is concerned that exclusion from this area in
recent years forces catch rates to be lower than historical levels.

Industry believe that this constraint on catch rates is demonstrated by the events of the 1998 season, when
the principal survey vessel recorded an average catch rate of 2,500kg/day from 5 - 19 July after which the


98                                                                         SEF Species Summary 1999
Barrenjoey Pt boundary constrained its fishing. Industry claims that similar catch rates could have been
maintained over several weeks if surveying had been allowed to continue on the traditional (pre-1989) SEF
trawl grounds north of Barrenjoey Pt. The industry members argued that this would have increased the
1998 estimate of catch rates (926 kg / std day) by a substantial amount. On the other hand, some members
of EGAG also expressed concerns that international experience had shown that commercial catch rates
provide little information about abundance when stock size is low.

None of these concerns can be resolved with the data currently available to EGAG. The debate highlighted
the need for EGAG to give a high priority to improving the design of future surveys.

Environmental Conditions

According to fishers before the season, the environmental conditions approaching the 1998 season were
more 'normal' than in 1997 and they were hopeful of good catches.

In 1997 the weather during the gemfish season was dominated by slow moving high pressure systems
centered on Adelaide, few frontal systems crossed southern Australia from the west during the winter, and
there was little of the westerly weather that fishers associate with good gemfish seasons. In 1997 Sea
Surface Temperatures (SST) through the area were warmer than usual and the detachment point for the
EAC only moved as far north as Jervis Bay (around Latitude 35S). The peak survey catches of 1997
occurred on 13 July in the vicinity of the EAC's detachment point at Jervis Bay. Large catches ended
within a few days of this peak.

In contrast in 1998 many frontal systems swept across the area during the winter. A marked feature of the
1998 season was the repeated formation of deep depressions in the vicinity of Sydney. These brought
strong winds and rains to the study area and historic floods occurred in east Gippsland and around
Wollongong during the 1998 season. Sea Surface Temperatures (SST) were lower through the area than in
1997. In 1998 the detachment point of the EAC reached 31S in late May. The EAC was flooding south
again when the gemfish season commenced in late June early July. During the peak of the gemfish season
the detachment point of the EAC remained relatively stationary between 33.0S and 33.5S just to the north
of Barrenjoey point and temperature gradients in the area intensified. SST imagery showed that there was
an extremely active frontal system in this area throughout the survey period and in the following weeks.
Co-incidentally the aggregation that was followed with the surveys tracked the 17C surface front north to
the vicinity of the detachment point.

Unlike 1996, but similarly to 1997, the survey catches contained almost no running ripe fish suggesting that
main spawning area in 1998 was north of Barrenjoey.

Results

The results for the 1998 assessments are shown in Table 2 and Figures 1 and 2. Trends in biomass and
recruitment from 1968 to 1994 are very similar to those for the 1997 assessment and also for the cohort
analysis (Allen 1998). Results for the 1998 base case analyses include:

   the 1998 winter stock size (mid-season biomass) is estimated to be in the range 2000-2700t, which is
    13 to 18 % of unexploited equilibrium biomass

   estimates of 1998 spawning biomass relative to the 1979 level range from 22 to 29%

   the assessment confirms an increase in biomass occurred during the mid 1990s, but suggests a decline
    from 1996 to 1998 (Figure 1)

   the population is still predicted by the model to be dominated by the year class spawned in 1990. In
    that year an unexpectedly large number of young was produced from a relatively low level of spawning
    stock (Figure 1)

   the year classes between 1987 and 1995 are on average only about 20% of those between 1973 and
    1986; this could be either an effect of reduced breeding stock or a shift in environmental conditions or

Eastern Gemfish                                                                                          99
    a combination of the two. This pattern of recruitment is largely independent of the uncertainties
    reflected in the base case analyses (Figure 2)

   the 1998 assessment is in-line with the base case assessment for 1997.

Results of the 1998 assessment are still sensitive to the catch rate data for 1996 and 1997, although less so
than for the 1997 assessment. This is because the 1998 survey catch rate lies on the trend line predicted by
the 1997 assessment. Table 2 shows the effects of leaving out either the 1996 or 1997 catch rate, relative to
the base case analysis (which includes both data points). The results show that:

   leaving out the 1996 catch rate leads to a more optimistic assessment
   leaving out the 1997 catch rate leads to a more pessimistic assessment
   in neither case does this result in the stock being estimated to exceed the 40% of 1979 management
    threshold

In summary, the 1998 assessment is broadly consistent with the 1997 assessment in terms of historical
trends in biomass and recruitment. As expected from the 1997 assessment the biomass has declined further
due to the impact of natural mortality on the strong 1990 year class. With the exception of the 1990 year
class, recruitment is estimated to have been consistently low in recent years.

Industry observations, measurement of small fish in the survey, and the summer length frequency indicate
that the 1996 year class is stronger than preceding years. At present however there is no means of
quantifying the size of this year class.

Although the current assessment mimics the catch rate, age, length and sex ratio data well, some members
of EGAG expressed their reservations about the accuracy of estimates of current biomass.

In summary:

   The current biomass of eastern gemfish is estimated to lie between 1800-3400t or 11 to 22% of the
    unexploited equilibrium level. The current assessment suggests that the stock is between 20 and 37%
    of the 1979 level, which is below the reference level of 40%.

   The range of values for biomass and depletion result from the key uncertainties identified by EGAG in
    the current assessment. These uncertainties include the historical levels of catch, the validity of recent
    catch rate surveys, the form of the stock recruitment relationship, and the possibility of density
    dependent selectivity.

   The assessment of time trends in biomass and recruitment is in broad agreement with previous
    assessments. The assessment indicates that there was a period of good recruitment from the early
    1970s until the mid 1980s, but that subsequent recruitment has been much lower, with the exception of
    a relatively strong 1990 year class. The explanation for this pattern of recruitment remains uncertain,
    but the pattern itself is robust to the uncertainties in the assessment.

   The stock is assessed to be decreasing as the 1990 year class declines, and is replaced by weaker year
    classes spawned from 1992 to 1994. This decline is projected to continue to at least the year 2000.

   The by-catch arrangements for 1998 (allocated TAC rather than trip limits) appear to have worked
    well. Estimated total catches are well within the allocated TAC, the incidence of targeted eastern
    gemfish fishing was greatly reduced, and the estimated level of discarding (15t) is low.

   Given the current assessment, there is less need for a survey in 1999 to provide an estimate of relative
    abundance than in the last three years. However a continued high priority should be given to measuring
    the size and age composition of the catch in 1999.

   EGAG will place emphasis during 1999 on redesigning the survey program to obtain better and earlier
    information on recruitment to the fishery, and on obtaining an index of abundance that is less
    dependent on fishing patterns. This may involve additional input from an expert in fishery survey


100                                                                          SEF Species Summary 1999
    design.


6. IMPLICATIONS FOR MANAGEMENT

Approach
In the 1998 assessment, several simple harvest strategies were evaluated using estimates of the current state
of the stock and a model to predict future stock dynamics. For this report, the current state is based on the
uncertainty reflected in the Bayesian posterior distribution for each of the eight base case analyses. EGAG
considered that these reflected the range of uncertainties in the current assessment. The projections make
use of information about year classes already in the recruited population and make assumptions regarding
the strengths of future year classes.

Harvest strategies
For the 1998 assessment, EGAG considered only fixed catch harvest strategies in assessing the
consequences of future catches on the stock. This was because the stock was assessed to be below the
management threshold for a targeted fishery. Projections for each of the eight analyses (sensitivity tests)
are made assuming future catches of 250t. This level is approximately equal to the total catch by all sectors
in 1998. For one of the sensitivity tests (number 6: series A, B-H, Dens S), projections were made for
future catch levels of 0, 250, and 500t. Projections are over 10 years.

The catches used in these evaluations refer to the total catch by all fishing methods. It is assumed that 95%
of the catch is taken by the winter fishery and 5% is taken by the summer fishery.

It should be noted that fixed catches over 10 years are not considered to be realistic nor likely to be
implemented as described. The reason for considering these strategies is that they reflect some of the short-
term decision alternatives available to management, and allow the evaluation of risk or probabilities of
medium-term outcomes for different types of decision. Alternative strategies could also be examined. For
example Punt and Smith (1998) evaluated a range of feedback harvest strategies for eastern gemfish.
However these evaluations have yet to be properly considered by EGAG. Such evaluations are a priority
for future work of EGAG.

Performance indices

Egag used two performance indices to measure how well each strategy meets management objectives:


 the ratio of the mid-season biomass during year y to the unexploited equilibrium level - By/B0

 the ratio of the 5+/6+ biomass at the end of year y to that at the end of 1979 - Ey/E79 (noting that this
  ratio should exceed 0.4 to meet the management requirements for a targeted fishery)

Results
The stock projections for the base case analyses under future 250t fixed annual catches are shown in Figure
3. For all analyses the stock is expected to decline further until the year 2000, after which the model
indicates a greater than 50% probability of some recovery. However the strength of this recovery is
dependant on the size of the 1995 and following cohorts which are currently poorly estimated. Table 3
shows, for each base case analysis, the minimum level of depletion (relative to 1979 and relative to
unfished levels) and the year in which it is expected to occur. The minimum level of spawning biomass
relative to 1979 is in the range 12 to 22%. Finally, Figure 4 shows, for one of the base case analyses
(analysis 6, one of the ―middle‖ projections in Figure 3), the stock projections under future catch levels of
0, 250 and 500t.

7. RESEARCH NEEDS

Industry trawl surveys have been planned in each of the past three seasons and were undertaken in 1996,
1997 and 1998 (Prince 1996, Prince, Griffin and Diver 1998). The primary objective for each of these


Eastern Gemfish                                                                                          101
surveys has been to obtain catch rate information comparable with commercial catch rates prior to 1991.
The design of the surveys has varied slightly each year in an effort to best achieve this objective. Although
this objective of comparability with earlier data has been the driving force in survey design, it has been
recognised each year that the current survey design is not necessarily optimal in the longer term.

Given the current stock assessment and the projections of further decline for the next several years, it may
be an appropriate time to redesign the survey with longer term considerations in mind. The primary
objective in this redesign should remain obtaining a reliable and consistent index of abundance in as cost-
effective a manner as possible. Although it will be several years before a new time series of surveys can be
used in the assessment, continued monitoring of catch composition should allow annual updating of the
assessment, though with less certainty until the new time series of abundance indices can be used.
Alternatively, the current survey strategy could be continued, but with surveys conducted less frequently
than every year. The consequences of each of these strategies, and considerations of alternative survey
designs, will be the main focus of the next meeting of EGAG.

Given the current assessment, there is less need for a survey in 1999 to provide an estimate of relative
abundance than in the last three years. However a continued high priority should be given to measuring the
size and age composition of the catch in 1999.

EGAG will place emphasis during 1999 on redesigning the survey program to obtain better and earlier
information on recruitment to the fishery, and on obtaining an index of abundance that is less dependent on
fishing patterns. This may involve additional input from an expert in fishery survey design.

References

Allen, K.R. (1989) A cohort analysis of the gemfish stock of southeast Australia. Report prepared on
     behalf of Unisearch Limited for the Fishing Industry Research and Development Council. August
     1989.
Allen, K.R. (1992) Gemfish analysis as at September 1992. Document submitted to Demersal and Pelagic
     Fish Research Group 33.
Allen, K.R. (1998) An update of cohort analysis for gemfish. Document submitted to the 18 - 19 August
     1998 meeting of EGAG.
Chesson, J. (1995), Eastern Gemfish 1994, Stock Assessment Report, South East Fishery Assessment
     Group, Australian Fisheries Management Authority, Canberra
Chesson, J. (1996) Eastern gemfish coordinated modelling project: Outcomes of meeting, 21-22 March
     1996. Report prepared for the Australain Fisheries Management Authority.
Prince, J.D. (1996) Industry survey of the 1996 eastern gemfish spawning season. FRDC Project 96/1557,
     Final Report.
Prince, J., Griffin, D. and Diver, G. (1998) Industry survey of the 1997 eastern gemfish season. FRDC
     Project 97/147, Final Report.
Punt, A.E. (1996) Preliminary stock assessments of eastern gemfish (Rexea solandri) using Bayesian and
      maximum likelihood methods. pp. 6-67. In: Smith, A.D.M. (ed.) Evaluation of Harvesting Strategies
      for Australian Fisheries at Different Levels of Risk from Economic Collapse. FRDC Report T93/238.
Punt, A.E. (1998b) Bayesian assessments of the eastern stock of gemfish using data for the 1998 winter
      fishing season. Document submitted to the 1 - 2 October 1998 meeting of EGAG.
Punt, A.E., Rowling, K. and Prince, J. (1998) Summary of the data for use in the assessments of the eastern
      stock of gemfish based on the 1998 fishing season. Document submitted to the 1 - 2 October 1998
      meeting of EGAG.
Punt, A.E., and Smith, A.D.M. (1998) Further preliminary evaluation of management procedures for the
      eastern stock of gemfish (Rexea solandri). Document submitted to the 19-20 March 1998 meeting of
      EGAG.




102                                                                        SEF Species Summary 1999
Table 1      The eight analyses considered in the 1998 base case assessment.


 Analysis         Abbreviation        Catch series   Stock-recruitment   Density-dependent
                                                                            selectivity
                                                        relationship
    1            Series B; B-H             B           Beverton-Holt           No
    2            Series A; B-H             A           Beverton-Holt           No
    3           Series B; Depen            B            Depensatory            No
    4           Series A; Depen            A            Depensatory            No
    5        Series B; B-H; Dens S         B           Beverton-Holt           Yes
    6        Series A; B-H; Dens S         A           Beverton-Holt           Yes
    7       Series B; Depen; Dens S        B            Depensatory            Yes
    8       Series A; Depen; Dens S        A            Depensatory            Yes




Eastern Gemfish                                                                              103
Table 2       1998 assessment results. Sensitivity to ignoring the catch-rates for 1996 and 1997. All of the analyses include the data point for 1998.


 Analysis                       Base-case                                        Less 1996 catch-rate                                  Less 1997 catch rate
                                                5 / 6     5 / 6 
             B0         B1998       B1998/B0   B98         /B
                                                            79
                                                                        B0      B1998     B1998/B0     5          5
                                                                                                      B98 / 6  / B79 / 6     B0     B1998     B1998/B0     5          5
                                                                                                                                                            B98 / 6  / B79 / 6 
      1     18637       2658         0.143          0.291              18396    2197          0.119            0.258          18579   3378          0.182            0.371
      2     13825       2458         0.178          0.255              13556    2194          0.162            0.234          13819   3110          0.225            0.330
      3     19375       2582         0.133          0.293              19013    2142          0.113            0.259          19148   3278          0.171            0.373
      4     14996       2305         0.154          0.257              14606    2042          0.140            0.233          14797   2943          0.199            0.330
      5     16868       2342         0.139          0.252              16994    2030          0.119            0.231          17040   2943          0.173            0.321
      6     16951       2361         0.139          0.238              14021    1952          0.139            0.202          14124   2650          0.188            0.278
      7     17199       2272         0.132          0.254              17275    1976          0.114            0.230          17303   2847          0.165            0.321
      8     14186       1972         0.139          0.217              14088    1801          0.128            0.201          14215   2479          0.174            0.278




104                                                                      SEF Species Summary 1999
Table 3      Minimum median depletions and year of minimum under future fixed
             250t catches for the eight base case analyses.

                       Analysis   Ey/E79   By/B0   Year

                          1       0.219    0.127   2000
                          2       0.171    0.147   2000
                          3       0.207    0.106   2001
                          4       0.161    0.112   2000
                          5       0.172    0.108   2000
                          6       0.146    0.090   2000
                          7       0.165    0.086   2001
                          8       0.121    0.083   2001




Eastern Gemfish                                                           105
                                    1000
                                     900

            Total catch (tonnes )
                                     800
                                     700
                                     600                   actual / approved TAC
                                     500
                                     400
                                     300
                                     200
                                     100
                                       0
                                             1992   1993      1994      1995       1996    1997    1998

                                                                       Year

Figure I Total annual verified trawl catches of eastern gemfish calculated from the
         quota monitoring system (SEF2), and actual and approved total allowable
         catches (TAC)




                                    300

                                    250
          av. catch rate (kg/hr)




                                    200

                                    150

                                    100

                                    50

                                     0
                                          85 86 87 88 89 90 91 92 93 94 95 96 97 98 99


Figure II Average annual unstandardised catch rate of eastern gemfish




106                                                                                       SEF Species Summary 1999
Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Eastern
Gemfish

                                       Commonwealth Records                                                         State Records
                     TAC                        Retained Catch                                                     Retained Catch




                                                                                                                                                       catchwithin SEF



                                                                                                                                                                          discarded catch1
                                        Commonwealth




                                                                                                                                                        Estimated total
                                                                                                    NSW dropline
                                                       SEF 2 State




                                                                                                                                                                             Estimated
                                                                                                                       Tasmania
                           Allocated




                                                                                                                                       Victoria
                                                         Waters
            Agreed




                                                                                        Total4
                                                                     SEF 1


                                                                             Other
                                           SEF2




                                                                                                                                                             area3
  Year




 1980
 1981
 1982
                                                        SEF not Established
 1983
 1984                                                                        2495       2495                2                                                 2497
 1985                                                                        2776       2776                9                                                 2785
 1986                                                                        2995       2995               10                                                 3005
 1987                                                                        4046       4046                8                                     90          4144
 1988                      3000                                              3654       3654                7                                     64          3725
 1989                      3000                                              1936       1936                5                                     94          2035
 1990                      1750                                      1198               1198               26                     24               5          1253
 1991                       500                                       561                561               11                      4               4           580
 1992        200            208               576               3     386                579               25                      3              22           629
 1993         nil            nil              253              14     212                267               25                      1              10           303                790
 1994         nil            nil              134               9     120                143               52                      1               2           198                 33
 1995         nil            nil               93               4      74                 97              104                      2              19           222                 14
 1996         nil            nil              111               6     192                117               50                      6               6           179
 1997       1000           1000               393               4     198                397               57                      7               ?           461
 1998        300            300               211               3       ?                214                ?                     <1               ?
                                                                                                 Combined Eastern and Western gemfish records
 Commonwealth records:                                                               State records:
      1984 - 1989 verified catch history                                                  NSW Dropline              NSW catch and effort database
      1990 - onwards SEF Logbook                                                          {K. Rowling)
      1992 - onwards AFMA quota monitoring unit
 (    SEF2)                                                                               Tas:                      Tas. DPI logbook
 From 1992, Western Gemfish was managed separately.                                       (Dr. J. Lyle)

 1.   Estimated from the SMP                                                                         Abbreviations:
 2.   State location                                                                                      N/A = Not Applicable
 3    Estimated by totaling Commonwealth and State records                                                ND = No Data Available
 4    Total of shaded cells                                                                                ? = Available data not received




Western Gemfish                                                                                                                                            107
       GEMFISH WESTERN
1.      AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS

        Objectives
        Ongoing
     1. To ensure that the western gemfish resource is utilised in a manner consistent with the
        principles of ecologically sustainable development.

        Immediate objective
     2. To ensure that the recruited biomass of western gemfish does not significantly decline
        below its current (1994) level:
              noting that the SEF portion of the fishery only encompasses the eastern extremity of
               the western gemfish stock,
           current jurisdictional boundaries and varying approaches to management by different
            Commonwealth fisheries needs to be taken into account if this objective is to be
            achieved.
        Ongoing
     3. To maximise the economic efficiency of the western gemfish fishery.
     4. To implement effective and efficient fisheries management on behalf of the
        Commonwealth.

       Strategies
       The above objectives will be achieved by:
     1. setting a TAC for the Commonwealth managed portion of the fishery:
              that in the SEF maintains catch per unit effort (CPUE) above its lowest annual
               average level from 1986 to 1994
              the TAC would only apply to the trawl sector of the fishery
·       (objectives 1 & 2)
     2. developing complementary management arrangements between the Great Australian Bight
        Trawl Fishery (GABTF) and the SEF, such that CPUE in sectors under Commonwealth
        jurisdiction is maintained above its lowest annual average (1986-1994) level
        (objective 1 & 4)
     3. prioritising western gemfish research in relation to other SEF species:
              SETMAC has given a medium research priority rating to this species
         (objectives 1, 2, 3 & 4)
     4. data collection:
         (i)   obtaining estimates of catch, catch rate and monitoring shifts in effort and changes in
               fishing practices
         (ii) monitoring length distributions in commercial catches and collecting aging data when
              required
         (objectives 1 & 2)
     5. undertaking economic research on the fishery to calculate GVP and monitoring market
        prices for western gemfish
        (objective 3)



       Performance indicators
     1. That the current annual CPUE for the fishery is above its lowest annual average from 1986
        to 1994
        (strategy 1)


       108                                                                          SEF Species Summary 1999
     2. That complementary management arrangements are developed between the GABTF and
        the SEF
        (strategy 2)
     3. Data relevant to the annual assessment of western gemfish has been collected and analysed,
        and considered by SEFAG
        (strategies 1, 3, 4 & 5)
     4. The actual trawl catch relative to the trawl TAC
        (strategy 1)

2.       STOCK STRUCTURE AND LIFE HISTORY

        A recent genetic study identified two distinct Australian gemfish stocks, with Bass Strait
        and Tasmania constituting the boundary between these populations. Western gemfish
        occur in outer shelf and slope waters from western Tasmania/western Bass Strait across the
        Great Australian Bight to the west coast of Western Australia (as far north as 23 o 25' S).
        Commercial fishing for western gemfish west of 138o30 E is managed separately as part of
        the Great Australian Bight (GAB) Trawl Fishery.
        Spawning appears to occur in summer, and most reports of fish in spawning (i.e. ripe)
        condition have come from the west of the GAB. Growth, age at maturity (3-6 years) and
        longevity (16 years) are similar to eastern gemfish. A total mortality estimate of 0.41 for
        western gemfish was obtained from analyses of the age composition of 1988-89 SEF
        commercial catches.

3.       THE FISHERY

        Current situation
        The 1998 SEF2 landed weight of western gemfish was 185 t (All in Commonwealth
        waters), which was 55% of the actual TAC of 334 t. It represents a 19% decrease in
        landings compared to 1997 (227t). The 1999 agreed TAC is 300 t, with an actual TAC of
        346 t.

        There were generally poor landings of western gemfish (~130 t) during 1992 to 1995 and
        AFMA‘s catch rate performance criteria was triggered in 1995 at 30.6 kg/hour. Since then,
        catches and catch rates have improved. Landings of western gemfish by the GAB trawl
        fishery in 1998 were 64 t ?? If this fishery continues to develop, priority should be given to
        developing complementary management measures. As western gemfish in the SEF appear
        to be at the eastern end of their distribution, it is unclear if changes in catch rates are in any
        way related to overall stock abundance. Unlike eastern gemfish, most of the western
        gemfish catch is taken in multi-species catches, usually with blue grenadier and ling.

        The gross value of landed catch of western gemfish in 1998 was estimated to be $0.6
        million, slightly lower than in 1997. In 1998, market prices for gemfish (eastern and
        western) averaged $4.00 kg, significantly higher than 1997 ($2.65).

4.       PREVIOUS ASSESSMENTS

        DPFRG examined catch and biological data in 1990. Standing crop estimates from the
        1988-89 western Bass Strait trawl survey were the principal data used. DPFRG concluded
        that, because catches were approximately 20 per cent of known biomass and catch rates
        appeared to be stable, annual catches of up to 300 t appeared to be sustainable. The 1994
        assessment incorporated 1992 and 1993 catch/effort data and consisted of a more detailed
        analysis of catch, effort and catch rates by depth in the SEF Western Zone. Of annual
        catches 80 per cent or more come from the depth range 250 m to 400 m. Catch rates in that
        depth zone declined from a peak of 82.5 kg/hr in 1987 to 31.3 kg/hr in 1993, suggesting a
        decline in abundance of western gemfish in the SEF component of its distribution.
        However, because the SEF fishery is on the eastern end of the stock, it was not known if



       Western Gemfish                                                                                       109
      this decline is attributable to fishing (within or outside the SEF) or factors other than
      fishing.

      Available data were examined at the SEFAG Working Group I meeting held in April 1995.
      1994 seasonal catch rates for western Tasmania and west of Bass Strait were amongst the
      lowest recorded since 1986, but there was some suggestion that the declining trend of
      recent years had stabilised. The results of a GLM analysis of annual catch rate data for the
      SEF fishery as a whole supported this interpretation. Available size composition data for
      catches landed at Portland suggested that there were fewer large fish (>70 cm. LCF) in the
      1993 and 1994 catches than there were in the 1991 catch. It was not known whether these
      fluctuations in size composition were related to the impacts of fishing, or to natural
      fluctuations in movement patterns, or to changes in relative cohort abundance (ie.
      recruitment variability).

      A workshop was held at SARDI, Adelaide in November 1996. Comparison between mean
      annual catch rates for 3 individual vessels found good correlation between 2 Beachport-
      based vessels over the period 1991 to 1995 (allowing for the fact that one did not target
      gemfish in 1993), with both showing an overall decline. Catch rates for the Portland-based
      vessel over the same period were lower and more stable, but closely matched the mean
      unstandardised (total effort and total catch) catch rate for the 250-399 m depth range in the
      western zone from 1992 to 1995. All catch rates indicated that there had been a decline in
      western gemfish abundance and/or catchability from the mid-1980s to the mid-1990s.
      Preliminary analysis of January to June 1996 logbook data suggested that catch rates were
      improving in 1996. Post-workshop analysis of catch data for the whole of 1996 confirmed
      that the mean annual catch rate was higher than those for 1995 and 1994. The Beachport
      vessels‘ catch rates showed a marked improvement from 1995 to 1996, but the rise was
      much less pronounced with the Portland vessel and the mean 250-399 m depth range catch
      rates. However, the mean 250-399 m catch rate for 1996 was probably depressed by the
      large (58%) increase in effort in this depth range from 1995 (2940 hrs) to 1996 (4657 hrs).
      Irrespective of the actual magnitude of the increase in catch rates, there is no doubt that the
      fishery improved in 1996. Port landings and SMP data showed that 1996 catches contained
      predominantly 40-60 cm LCF fish (2-4 yr olds), whereas 1995 catches contained
      proportionately more larger, older fish. Estimates of biological parameters for western
      gemfish remain the same as earlier assessments.

5.    1999 UPDATE
      There was no formal assessment of western gemfish undertaken during 1999. However,
      1998 logbook and ISMP data were incorporated into this update.
     Catch and effort
     The 1998 SEF2 landed weight of western gemfish was 185 t (All in Commonwealth
     waters), which was 55% of the actual TAC of 334 t. It represents a 19% decrease in
     landings compared to 1997 (227t) and 62% of the agreed TAC of 300 t. The 1999 agreed
     TAC is 300 t, with an actual TAC of 346 t.
      Catch rates of western gemfish have displayed a continual decline since 1988 (85.7 kg/hr)
      reaching a record low of 30.6 kg/hr in 1995 which triggered AFMA‘s catch rate
      performance criterion. In 1996, catch rates improved markedly (59 kg/hr) but have dropped
      slightly in 1997 (48.0 kg/hr) and 1998 (46.1 kg/hr).
     Size composition
      During 1998, the length frequencies of gemfish landed to the west of Bass Strait generally
      ranged between 40 and 80 cm LCF. Although some fish less than 40 cm were caught, they
      were usually discarded. Fish greater than 50 cm were always retained.
     Discard rates
      Although there was relatively low levels of discarding of western gemfish in 1995 (5.9% by
      weight) and 1996 (8.4%), increased catches during 1997 were accompanied by much
      higher levels of discarding (20.4%). This may, in part, be attributable to the continuing
      increase in fishing effort in the Western Zone, with the 1997 SEF1 total of 17 802 hours


     110                                                                           SEF Species Summary 1999
            bottom-time being the highest on record. However, during 1998, discarding of western
            gemfish reduced considerably to around 2%. Effort levels (14 424) were also lower.
           Port visits
            Industry feedback from the 1998 port meeting confirmed previous comments that although
            catches had been poor over an number of years in the early 1990s, they had improved in
            recent years. Good catches continued during 1998 and into 1999 although they were
            slightly down compared to 1997. Portland was considered as near the eastward end of the
            western gemfish distribution and fish come through Beachport before reaching Portland.
            Beachport has been the main port for western gemfish landings in recent years. This is
            thought to reflect the larger area of trawlable grounds at suitable depths available off
            Beachport compared to that available off Portland. Catches in Beachport included large
            adult fish as well as smaller sub-adult fish. Large mirror dory were often caught with the
            gemfish.
           Prices
            In 1998, the gross value of recorded landings of gemfish was estimated to be about $1.19
            million. The average price on the Sydney fish markets was $3.24/kg, which was higher than
            that on the Melbourne Fish Market ($2.71/kg).



      6.   IMPLICATIONS FOR MANAGEMENT

            Maintenance of a healthy western gemfish stock is important, not only to sustain the fishery
            based on this stock but also for conservation reasons, in view of the substantial decline of
            the eastern gemfish stock and the attendant interest from conservation groups. The catch
            rate in 1997 was above the previously triggered (i.e. in 1995) AFMA performance
            criterion. It is still not clear whether the overall decline in catches and catch rates for
            western gemfish from 1991 to 1995 was associated with a reduction in stock abundance,
            and if so, whether such a reduction is attributable to fishing (in the SEF and/or GAB areas),
            changes in gear or other factors such as fluctuating recruitment. As western gemfish in the
            SEF appear to be at the eastern end of their distribution, it is unclear if changes in catch
            rates are in any way related to overall stock abundance. Stock status remains unknown.

            Overall trawl fishing effort in the western zone continues to rise significantly (from 10214
            hrs bottom time in 1994 to 13734 hrs in 1995, 16200 hrs in 1996 and 17802 hrs in 1997). It
            is obvious that shelf/upper-slope resources in the western zone are being subjected to
            increasing fishing pressure even if, like western gemfish, they are largely a by-catch
            species.

            Landings of western gemfish by the GAB trawl fishery in 1998 rose sharply to 64 t and if
            this fishery continues to develop, priority should be given to developing complementary
            management measures.


           7.   RESEARCH NEEDS


            Specific needs for western gemfish include:
 i)         Continue to collect representative size/age samples from SEF commercial catches to
            ascertain if recent reduced catch rates are associated with changes in abundance caused by
            fluctuating recruitment (ie. one or more poor cohorts), changes in mortality rates, or other
            factors. Achievement of this objective will require upgraded sampling of catches landed at
            Beachport. Attempts should also be made to collect samples from the GAB fishery if
            significant catches continue to be made there.
ii)         Detailed spatial analysis of logbook data to determine if distributional shifts in catches
            and/or abundance have occurred.




           Western Gemfish                                                                                  111
iii)   Basic biological studies (e.g. university projects) of western gemfish, particularly to
       determine reproductive characteristics.




       112                                                                         SEF Species Summary 1999
                                    400                                             actual TAC




             Total catch (tonnes)
                                    300
                                                                                    approved TAC

                                    200


                                    100


                                         0
                                             1992    1993    1994    1995    1996       1997       1998

                                                                     Year
Figure I Total annual verified trawl catches of western gemfish calculated from the
         quota monitoring system (SEF2), and actual and approved total allowable
         catches (TAC)




                                    90
                                    80
                                    70
          av. catch rate (kg/hr)




                                    60
                                    50
                                    40
                                    30
                                    20
                                    10
                                    0
                                         85 86   87 88   89 90   91 92 93   94 95     96 97      98 99


 Figure II Average annual unstandardised catch rates of western gemfish




Western Gemfish                                                                                           113
            Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Western
            Gemfish

                                        Commonwealth Records                                          State Records
                      TAC                        Retained Catch                                      Retained Catch




                                                                                                                                       catch within SEF



                                                                                                                                                          discarded catch3
                                         Commonwealth




                                                                                                                                        Estimated total
                                                        SEF 2 State




                                                                                                                                                             Estimated
                            Allocated




                                                          Waters
             Agreed




                                                                                      Total1
                                                                      SEF 1


                                                                              Other
                                            SEF2




                                                                                               NSW




                                                                                                                                             area2
                                                                                                                  Tas5
 Year




                                                                                                                            S.A.
                                                                                                        Vic5
1986                                                                    309              309   N/A                                              309
1987                                                                    251              251   N/A                                              251
1988                                                                    230              230   N/A                                              230
1989                                                                    157              157   N/A                                              157
1990                                                                    137              137   N/A                                              137
1991                                                                    273              273   N/A                                              273
1992            300             325            126                       92              126   N/A                                              126
1993            300             334            135                      103              135   N/A                                              135
1994            300             330            138                       96              138   N/A                                              138
1995            300             355            124                       85              124   N/A                                              124
1996            300             369            208                      146              208   N/A                                              208
1997            300             347            227                      140              227   N/A                                              227
1998            300             334            185                        ?              185   N/A                                              185

Commonwealth records:
        1986 - 1991 SEF logbook
        1992 onwards Quota Monitoring System (QMS)




1.      Estimated from the SMP                                                                 Abbreviations:
2.      State location                                                                              N/A = Not Applicable
3.      Estimated by totaling Commonwealth and State records.                                       ND = No Data Available
4.      Total of shaded cells                                                                        ? = Available data not received
5.      State landings assumed to be eastern gemfish




           114                                                                                                 SEF Species Summary 1999
Western Gemfish   115
      JACKASS MORWONG

1.    AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
      Objectives
      Ongoing
1. To ensure that the jackass morwong resource is utilised in a manner consistent with the
   principles of ecologically sustainable development.

      Immediate objective
2. To ensure that the spawning biomass of jackass morwong does not significantly decline
   below its current (1994) level:
       current jurisdictional boundaries and varying approaches to management by the States
        and Commonwealth need to be reconciled if this objective is to be achieved.
·
3. To maximise the economic efficiency of the jackass morwong fishery.


4. To implement effective and efficient fisheries management on behalf of the
   Commonwealth.

     Strategies
     The above objectives will be achieved by:
1. setting a TAC for the Commonwealth managed portion of the fishery that:
       maintains catch per unit effort (CPUE) above its lowest annual average level from
         1986 to 1994
      [Note: the TAC currently only applies to the trawl sector of the fishery within the SEF,
      excluding the southern Remote Zone]
      (objectives 1 & 2)

2. managing all sectors of the jackass morwong fishery in a complementary manner
   (objectives 1 & 4)


3. prioritising jackass morwong research in relation to other SEF species:
       SETMAC has given a medium research priority rating to this species
      (objectives 1, 2, 3 & 4)

4. data collection
      (i) obtaining estimates of catch, catch rates and monitor shifts in effort and changes in
          fishing practices
      (ii) monitoring length distributions in commercial catches and undertake ageing as required
      (objectives 1 & 2)

 5. undertaking economic research on the fishery to calculate GVP and monitor market prices
    for jackass morwong
    (objective 3)

     Performance indicators
 1. That the current annual CPUE for the fishery is above its lowest annual average level from
    1986 to 1994.
    [Note that if CPUE declines below 1986 - 1994 levels this would not necessarily result in a
    reduction in the TAC, but would require a report be made on the possible causes of the
    decline (within 12 months of the decline being brought to the attention of SEFAG/AFMA).



     116                                                                         SEF Species Summary 1999
      The report would form the basis of discussion as to whether management arrangements,
      including TACs, for jackass morwong needed to be reconsidered.]
     (strategy 1)

 2. That all sectors of the fishery are managed in a complementary manner
    (strategy 2)


 3. Data relevant to the annual assessment of jackass morwong has been collected and
    analysed, and considered by SEFAG
    (strategies 1, 3, 4 & 5)


 4. The actual trawl catch relative to the trawl TAC
    (strategy 1)

2.   STOCK STRUCTURE AND LIFE HISTORY
     Jackass morwong are distributed around the southern half of Australia (including
     Tasmania), New Zealand, the St Paul and Amsterdam Islands (Indian Ocean), and off
     south-eastern South America and southern Africa. They occur to depths of 450 m and, in
     Australian waters, are most abundant between 100 and 200 m.
     Jackass morwong spawn during late summer and early autumn. They have pelagic
     postlarvae which metamorphose to the adult form at 9-12 months old. Icthyoplankton
     studies have shown such larvae to be widely distributed (up to 250 km offshore). Juveniles
     (< 20 cm. LCF, ages 1-2) are found in inshore nursery areas in Bass Strait and around
     Tasmania. However, they are almost absent from the major fishery in southern NSW and
     north-eastern Victoria. They move into this area as they become sexually mature at about
     three years of age. Ageing studies using sectioned otoliths have recently extended their
     maximum age in Australia from 20 to 35 years.
     Recent genetic studies conducted by CSIRO have shown no evidence of separate stocks in
     Australian waters, but New Zealand and Australian stocks are distinct. Analysis of otolith
     microstructure found differences between jackass morwong from southern Tasmania and
     those off NSW and Victoria, but it is unclear if such differences indicate separate stocks.


3.    THE FISHERY
     Current situation
     The SEF2 recorded catch of jackass morwong in 1998 was 883 t (878 t in Commonwealth
     waters and 5 t in state waters), which was 50% of the allocated TAC of 1779 t and 22% less
     than 1997 landings (1136 t). It represents a 22% decrease in landings compared to 1997
     (1136 t). The initial TAC (1992) was set at 1500 t and has remained at that level, plus
     additional carryover tonnage. The 1999 agreed TAC is 1500 t, with an actual TAC of
     1811t.

     Catches of jackass morwong rose to a peak in 1989 of 1600 t. They have since dropped,
     but have remained relatively stable at between 700 and 1000 t. They are caught
     predominantly by trawlers in the eastern zones but around 10% of the catch is taken west of
     Bass Strait. Since 1989, the mean unstandardised catch rate of jackass morwong has
     continued to decline and in 1995 and 1996 it fell below AFMA's catch rate performance
     criterion. Although an increase in catch rate reversed this trend in 1997, the 1998 catch
     rate has again fallen below the performance criterion.
     The gross value of recorded landings taken by Commonwealth trawlers in 1998 was
     estimated to be $1.7 million, 3 per cent higher than in 1997. This was due to a rise in
     recorded landings. In 1998, prices for morwong averaged around $1.90/kg which is
     substantially below previous years. The return to the fisher (net of marketing charges) in
     1998 was about $1.50/kg.



     Jackass Morwong                                                                               117
     Targeting of jackass morwong is still mainly market driven. Competition on the domestic
     market with imports from New Zealand was a common concern of industry. In 1997, 268
     tonnes (product weight) were imported from New Zealand, of which 229 tonnes were
     chilled and frozen fillets. Over the period 1992 to 1997, imports from New Zealand have
     averaged 300 tonnes annually.
     Some operators reported that small morwong are being caught, resulting in high-grading.
     However, SMP data show a low rate of discarding (1-6% by weight, annually) off southern
     NSW during 1993-96. Industry had some minor concerns over the stock‘s status, but most
     operators believed the decrease in catch rates is a result of environmental factors rather
     than a decrease in fish abundance.



4.    PREVIOUS ASSESSMENTS
     Eastern Sector biomass was estimated to be about 10 000 t in the mid-1980s, using a
     combination of trawl surveys and VPA. Recruitment to this area is thought to be
     characterised by occasionally strong year classes. Age-structured modelling of the NSW
     component of the fishery indicated that Maximum Sustainable Yield (MSY) is approached
     with a fishing mortality (F) at 0.2 to 0.3 and the fishery was at optimum levels.
     At SEFAG 1993, recent whole otolith age data (from the CAF) and length data were
     presented together with new age and length data from south-eastern Tasmania. The
     instantaneous coefficient of total mortality (Z) was estimated from catch curves computed
     from age and length data. In eastern Bass Strait (1991-93), total mortality was similar to
     previous estimates in the early 1980s. Length and age data from south-eastern Tasmania
     were characterised by a greater proportion of larger and older fish. The main conclusion
     was that, although annual catches had declined, mortality estimates indicated that the
     fishery had remained stable in the Eastern Sector. Results from south-eastern Tasmania
     suggested that jackass morwong in this area were lightly exploited.
     Preliminary ageing data from sectioned otoliths were tabled at SEFAG in 1994. These
     suggested that morwong were longer lived (35 years) than was previously thought (20
     years). Natural mortality estimates would therefore be lower.
     A stock assessment of jackass morwong was undertaken in 1995. Catch records from 1986
     to 1994 were available from a number of sources: SET logbook, verified catch records, and
     the quota monitoring database. Catch and unstandardised effort by major area in the
     fishery were derived from logbook records for the period. For effort, only those shots in
     which the species was caught were used, and catch rates were expressed as kilograms per
     hour.
     1994 SMP data were again examined to determine discarding rates. As well as SMP
     measurements, length-frequency data were available for jackass morwong landed at Lakes
     Entrance 1991 - 1994 and from Tasmania 1983 - 1994. A more extensive age-length key
     derived from sectioned otoliths was available from the CAF.
     The pelagic postlarvae of jackass morwong (630 mm) had been found offshore (up to 240
     km) associated with oceanographic fronts. These have not been reported from waters on the
     continental shelf. Transport mechanisms are unknown.
     Whereas the 1994 assessment stated that catch rates had remained relatively stable for the
     previous 4 years, GLM-calculated trawl catch rates have exhibited a slow decline since
     1987. The significance, if any, of this decline remains poorly understood. Discarding of
     Jackass morwong in 1994 was again low (4 per cent by weight), being similar to that in
     1993 despite an increase in smaller recruits. Length frequency data showed that a pulse of
     new recruits, probably attributable to a strong year-class, had entered the Eastern Sector
     fishery in 1994.
     Mortality and yield estimates needed to be revised using the new ageing data.
     One of the major research needs highlighted in the 1995 stock assessment summary was for
     additional ageing work so that growth, mortality, yield and biomass estimates could be


     118                                                                      SEF Species Summary 1999
revised. During the past year, otoliths collected from the 1996 catch were sectioned and
aged. The 1997 stock assessment report presented preliminary results on the re-ageing of
jackass morwong that have enabled development of new growth curves and age-length keys
for males and females. These age-length keys were applied to annual length frequency data
to obtain new mortality estimates.
Trawl/Danish seine catch and effort data from 1986 to 1996 were available from the SEF
logbook (SEF1) and quota monitoring (SEF2) databases. It was acknowledged that there
were probably small but significant jackass morwong catches from the non-trawl sector
(line, gillnet, trap and recreational), but no catch data were available.
The 1997 assessment was based on the collation and analysis of catch and effort data,
combined with new biological information on jackass morwong growth rates. Information
on length frequencies and the retained and discarded catch of jackass morwong was
obtained from SMP data and the FRDC report by Liggins (1996). Further length-frequency
data were available from NSW and Tasmanian State projects. A series of discussions with
industry at port meetings at Ulladulla, Eden, Lakes Entrance and Portland, 27-31 March
1995 provided important input into the assessment. The draft assessment report was
discussed at the 1997 SEFAG Plenary Meeting.
All ageing was performed using standard techniques on sectioned otoliths. Estimates of
total mortality were obtained by applying the 1996 age-length keys to landed length
frequency data and analysing the resultant age frequency distribution with standard catch
curve analyses. Natural mortality estimates were based on life history parameters.
From 1984 to 1991, the recorded SEF jackass morwong catch ranged from 955 t (1990) to
1724 t (1989). In 1992, the initial TAC was set at 1500 t and it has since remained at that
level, with some additions due to carryovers. Similar to other years, about half of the
landings (412 t SEF1) were in Eastern Zone B with most of the remainder being caught in
Eastern Zone A (150 t) and Eastern Tasmania (162 t). Negligible amounts were landed
from the other zones. 1996 landings from Victorian endorsed vessels were low (1.2 t),
whilst landings recorded for Tasmanian endorsed vessels were 23 t, almost half that
recorded in 1995. Mean unstandardised catch rates (based only on shots containing jackass
morwong) in 1996 declined in each of the 3 major catch zones.
Measurements of the catches landed in Lakes Entrance between 1992 and 1996 show the
lengths range between 25 and 45 cm LCF. Apart from 1992, where a greater proportion of
smaller (27 - 30 cm) fish were apparent (possibly 2-3 year olds), the mode has remained at
around 31 - 33 cm. There has been a slight decrease in the proportion of larger fish caught
between 1993 and 1996, which is reflected by a reduction in the mean size of fish landed
from 1993 (34.4 cm) to 1996 (31.7 cm). Discarding of jackass morwong is low; around 4%
by weight over the period 1993 to 1996 (Liggins 1996, 1997). Usually, smaller fish (< 26-
27 cm) only were discarded.
The most recent ageing work yielded von Bertalanffy growth parameters for L 8, K and to
of 35.18, 0.41 and -0.2, respectively, for males and 36.39, 0.34 and -0.45 for females. The
resulting growth curves indicate that, despite being long-lived (30 - 40 years), the initial
growth rate of jackass morwong is rapid with fish reaching about 30 cm LCF at five years.
Growth then slows markedly, with little growth occurring after 10 years.
The natural mortality estimate based on the maximum age of 35 years for both males and
females was 0.09 yr-1.
The 1996 data provide the best available estimates of growth and mortality parameters for
jackass morwong. Application of the 1996 age-length key to the length frequency data from
Lakes Entrance revealed that, whereas fish ranged between 2 and 30 years old, most of the
catch consisted of fish less than 18 years old with the major mode being comprised of 4-5
year old fish. Variations in year class strengths indicated recruitment variability. Over the
last 20 years, there was slight evidence of stronger recruitment every 4-5 years.
Catch curve analysis on fish between 5 and 26 years old produced an estimate for total
mortality of 0.18 yr -1. This figure is considerably lower than previous estimates of 0.6 to
0.77 and is a direct result of the ―new‖ maximum age. It is also lower than the figures


Jackass Morwong                                                                                 119
     obtained by applying the 1993/94 age-length key (0.3 yr -1). Using the values for M (0.09)
     and Z,a fishing mortality (F) of 0.09 yr -1was estimated.
     Apart from the ageing work conducted on the 1996 sample, there has been insufficient
     ageing of annual samples to provide adequate age-length keys for 1992 to 1995 data.
     Although it is possible to apply the 1996 age-length key to these years‘ length frequencies,
     this is poor practice. Thus, the ability to compare age compositions between different years
     or follow the movement of year classes through the fishery is currently impaired.
     Fortunately, this problem can be overcome, as otoliths from years prior to 1996 have been
     collected and archived for future reading.
     The differences in the K values from the growth equation (0.34 - 0.41) relative to the
     calculated M value (0.09) suggest caution should be adopted in applying the M values
     across all age classes. Whilst the high K values result from the initial fast growth of the
     juvenile and sub-adult fish, the mortality estimates are based on fish greater than 5 years
     old. It is probable that natural mortality rates are far higher in the first few years.

5.   1999 ASSESSMENT
     There was no formal assessment of jackass morwong in 1999, but a brief examination of
     catch and effort data and ISMP data was undertaken.
     Catch and effort
     The initial TAC (1992) was set at 1500 t and has remained at that level, plus additional
     carryover tonnage. The SEF2 recorded catch of jackass morwong in 1998 was 883 t (878 t
     in Commonwealth waters and 5 t in state waters), which was 50% of the allocated TAC of
     1779 t and 22% less than 1997 landings (1136t). Annual landings of morwong by State-
     licensed vessels in Tasmania have varied between 70 and 140 t between 1990 and 1996 but
     there has since been a significant drop to 20 t in 1997 and 22 t in 1998. Catches by
     Victorian State-licensed vessels are negligible.
     Since 1989, the mean unstandardised catch rate of jackass morwong has continued to
     decline and in 1995 and 1996 it fell below AFMA's catch rate performance criterion.
     Although an increase in catch rate reversed this trend in 1997, the 1998 catch rate has again
     fallen below the performance criterion. Industry had some minor concerns over the stock‘s
     status, but most operators believed the decrease in catch rates is a result of environmental
     factors rather than a decrease in fish abundance.
     Size composition
     The length frequencies of jackass morwong landed off the NSW coast remained relatively
     stable between 1993 and 1997. Fish generally ranged between 25 and 40 cm with a single
     mode around 30 cm. During 1998, the length frequency distribution of fish off the NSW
     coast displayed a large peak with mode around 26 – 27 cm. Analysis of the ageing data
     would be required to determine if this represents entry of a new cohort into the NSW
     fishery. The peak was not apparent in other areas of the fishery, and length frequencies
     were more normally distributed with modes between 30 and 35 cm.
     Discard rates
     Discarding of jackass morwong is generally low (<5%) and operators report that some
     degree of high-grading occurs. Discard rates during 1998 were generally less than 3%,
     although they were slightly higher in the summer fishery off eastern Tasmania (~7%). In
     previous years, only fish under 25 cm were usually discarded but in 1998, some fish up to
     30 cm were discarded in eastern Bass Strait.
     Port visits
     During the 1998 port visits fishers in Eden noted that the abundance of morwong was
     increasing. They were abundant in 1996 but the market was not very good. Targeting of
     jackass morwong is still mainly market driven and fishers reported less interest in smaller
     species such as morwong. In previous port meetings, competition on the domestic market
     with imports from New Zealand was a common concern of industry.




     120                                                                        SEF Species Summary 1999
     Prices
     The gross value of recorded landings of morwong in 1998 was estimated to be about $1.55
     million similar to the total value in 1997. In 1998, prices for morwong averaged $1.74/kg
     lower than 1997 ($1.51). Market prices appear to exhibit a large degree of seasonality with
     prices peaking in late winter/early spring and bottoming in autumn. Melbourne prices have
     been consistently lower than Sydney prices over the last few years. In 1998, the average
     price on the Melbourne market was $1.18/kg.



6.   IMPLICATIONS FOR MANAGEMENT
     There is no hard evidence of separate jackass morwong stocks in the SEF. Observed wide
     larval advection and recent genetic studies by CSIRO provide further evidence for a
     common genetic stock probably occurring off S E Australia.
     The jackass morwong TAC has remained at 1500 t, but has never been reached as 1992-97
     SEF catch totals have ranged between 50-75% of this TAC. Whereas mean unstandardised
     catch rates in 1996 and 1995 triggered AFMA‘s catch rate performance criterion, catch
     rates improved significantly in 1997. The significance, if any, of the previous decline
     remains poorly understood and it is difficult to determine the extent to which recruitment
     variability has influenced catch rates. Biological indicators do not raise concerns about the
     current state of the jackass morwong stocks.
     The revised ageing data show morwong to have greater longevity and lower mortality rates
     than were previously reported. As the original TAC was partly based on yield estimates
     derived from parameters calculated from the earlier whole-otolith ageing, these estimates
     should be revised in light of the new ageing results.

7.   RESEARCH NEEDS
     Jackass morwong remains at a medium research priority. Formal analysis of catch and
     effort data is required to evaluate the usefulness of CPUE as an indicator of stock
     abundance. Depth should be treated as an important factor in such analyses, as Tasmanian
     studies have shown significant fish size differences with depth.
     Because recruitment is probably stochastic, age sampling strategies should be revised and
     improved to monitor relative cohort strength and help interpret CPUE data. As such, the
     re-ageing of archived otoliths to develop annual age-length keys for 1992-95 should be a
     high priority.
     Although increments seen in sectioned otoliths are fairly unambiguous, validation of the
     current ageing work is required. Using the new ageing and mortality data, yield and
     biomass estimates for the SEF jackass morwong fishery should be revised as soon as
     practicable.




     Jackass Morwong                                                                                 121
                       2000
                                                                                                       actual TAC
Total catch (tonnes)




                       1500
                                                                                                       approved TAC

                       1000


                       500


                         0
                                                    1992     1993   1994   1995   1996   1997   1998
                                                                           Year



                       Figure I Total annual verified trawl catches of jackass morwong calculated from the
                                quota monitoring system (SEF2), and actual and approved total allowable
                                catches (TAC)




                                                   100
                                                   90
                                                   80
                          av. catch rate (kg/hr)




                                                   70
                                                   60
                                                   50
                                                   40
                                                   30
                                                   20
                                                   10
                                                    0
                                                         85 86 87 88 89 90 91 92 93 94 95 96 97 98 99


                       Figure II Average annual unstandardised catch rates of jackass morwong




                       122                                                                      SEF Species Summary 1999
Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Jackass
morwong


                               Commonwealth Records                                           State Records
             TAC                        Retained Catch                                       Retained Catch




                                                                                                                          catch within SEF



                                                                                                                                             discarded catch3
                                Commonwealth




                                                                                                                           Estimated total
                                               SEF 2 State




                                                                                                                                                Estimated
                   Allocated




                                                 Waters
    Agreed




                                                                             Total1
                                                             SEF 1


                                                                     Other
                                   SEF2




                                                                                       NSW




                                                                                                                                area2
                                                                                                         Tas


                                                                                                                   S.A.
                                                                                               Vic
                                                                                      880
                                                                                      1800
                                                                                      1750
                                                                                      1350
                                                                                      1150
                                                                                      950
                                                                                      1050
                                                                                      1400
                                                                                      1200
                                                                                      1200
                                                                                      1050
                                                                                      2000
                                                                                      1500
                                                                                      1050
                                                                                      820
                                                                                      500
                                                                                      800
                                                                                      1650
                                                                                      1350
                                                                                      1800
                                                                                      1750
                                                                                      1450
                                                                                      650
                                                                                      640
                                                                                        ?            ?
                                                                                        ?            ?
                                                                                        ?            ?
                                                                                        ?            ?
                                                                                        ?            ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                                                        ?            ?         ?
                                                SEF not Established
                                                                                        ?            ?         ?
                               Commonwealth Records                                          State Records




Jackass Morwong                                                                                                                   123
                   Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Jackass
                   Morwong


                                         Commonwealth Records                                               State Records
                       TAC                        Retained Catch                                           Retained Catch




                                                                                                                                             catch within SEF



                                                                                                                                                                discarded catch3
                                          Commonwealth




                                                                                                                                              Estimated total
                                                         SEF 2 State




                                                                                                                                                                   Estimated
                             Allocated




                                                           Waters
              Agreed




                                                                                       Total1
                                                                       SEF 1


                                                                               Other
                                             SEF2




                                                                                                     NSW




                                                                                                                                                   area2
 Year




                                                                                                                        Tas


                                                                                                                                   S.A.
                                                                                                              Vic
1984                                                                           1101    1101                                                         1101
1985                                                                           1096    1096                                                         1096
1986                                                                    968     986     986         ND                                               986
1987                                                                   1076    1471    1471         ND           5                                  1476
1988                                                                   1442    1623    1623         ND           2         47                       1672
1989                                                                   1617    1724    1724         ND           1         99                       1824
1990                                                                    956             956         ND           6        100                       1062
1991                                                                   1106            1106         ND           4        106                       1216
1992          1500           1551             767              51       713             818         ND          <1        157                        975
1993          1500           1593             851             229       968            1080         ND          <1         70                       1150
1994          1500           1626             793              97       772             890         ND           1        141                       1032
1995          1500           1764             817              36       737             853         ND          <1         48                        901
1996          1500           1787             887               9       781             896         ND           1         24                        921
1997          1500           1800            1119              17       988            1136         ND           1         20                       1157
1998          1500           1779             878               5       761             883                                22

Commonwealth records:                                                                           State records:
                                                                                                        1946 - 1970 NSW landings
         1984 - 1989 verified catch history 4
                                                                                                        1970 - 1983 NSW & Vic landings
         1990 - 1991 SEF Logbook
                                                                                                        1975 - 1983 DPI Tas logbook
         1992 - 1998 AFMA quota monitoring unit
                                                                                                        1990 - 1998 Tasmanian DPI
                                                                                                        1997 - 1997 Victorian MAFRI



1.      Estimated by totaling complete Commonwealth and State                                        Abbreviations:
         records.                                                                                         N/A = Not Applicable
2       Total of the shaded cells                                                                         ND = No Data Available
3       Estimated from the SMP                                                                             ? = Available data not received
4.      1968 to 1973 estimated from ABS combined Morwong
         records, assuming 10% of weight of catch was rubber-lip
         morwong.




                   124                                                                                                 SEF Species Summary 1999
John dory   125
          JOHN DORY

1.   AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
           Objectives
           Ongoing
     1.   To ensure that the John dory resource is utilised in a manner consistent with the principles
          of ecologically sustainable development.

          Immediate objective
     2.   To ensure that the spawning biomass of John dory does not significantly decline below its
          1994 level:

            current jurisdictional boundaries and varying approaches to management by the States
             and the Commonwealth need to be reconciled if this objective is to be achieved.

     3.   To maximise the economic efficiency of the John dory fishery.

     4.   To implement efficient and effective fisheries management on behalf of the
          Commonwealth.

           Strategies
           The above objectives will be achieved by:

     1.   setting a TAC for the Commonwealth managed portion of the fishery that:


            maintains catch per unit effort (CPUE) above its lowest annual average level from
             1986 to 1994
               the TAC would only apply to the trawl sector of the fishery within the SEF, excluding
                the southern Remote Zone (Objectives 1 & 2)
     2.   managing all sectors of the John dory fishery in a complementary manner (Objectives 1 &
          4)

     3    prioritising John dory research in relation to other SEF species:
            SETMAC has given a low research priority rating to this species (Objectives 1, 2, 3 &
          4)
     4.   data collection
           (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing
               practices
           (ii) monitoring of length distributions in commercial catches and undertake ageing as
                required (Objectives 1 & 2)
     5.   undertaking economic research on the fishery to calculate GVP and monitor market prices
          for John dory (Objective 3)


Performance indicators
     1.   That the current annual CPUE for this fishery is above its lowest annual average level from
          1986 to 1994 (Strategy 1)

     2.   All sectors of the fishery are being managed in a complementary manner (Strategy 2)




          126                                                                         SEF Species Summary 1999
      3. Data relevant to the annual assessment of John dory has been collected and analysed,
     and considered by the SEFAG (Strategies 1, 3, 4 & 5)

      4. The actual trawl catch relative to the trawl TAC (Strategy 1)

2.    STOCK STRUCTURE AND LIFE HISTORY
     John dory (Zeus faber) inhabit the coastal and continental shelf waters of Australia, the
     western Indian Ocean, eastern Atlantic Ocean, Mediterranean Sea, Japan and New Zealand.
     In southern Australia its distribution stretches from Moreton Bay, Southern Queensland to
     Cape Cuvier, Western Australia. Most of the SEF John dory catch is taken off NSW.
     Although it is unclear whether the lower landings elsewhere in the fishery are due to lower
     John dory abundances or differences in fishing patterns between the areas, consistently
     lower catch rates in Eastern Sector B suggest that abundance declines to the south of NSW.
     For management purposes, a single stock is assumed for the SEF.

     Preliminary age and growth data suggest that John dory in the SEF are 3-5 years old at first
     maturity and live to around 12 years of age and a total length (TL) of 50 cm. However, in
     New Zealand females live up to 9 yrs and males 7 yrs, with both sexes growing rapidly in
     their first year and reaching an average length of 12-18 cm. In Australia, John dory have
     been recorded up to a weight of 3.5 kg and a TL of 75 cm. The length-frequency
     distributions of SEF commercial catches suggest that John dory are fully recruited to the
     trawl fishery at between 25-30 cm TL or approximately 3-5 years old (unvalidated age). In
     New Zealand, John dory are serial spawners with spawning occurring during December to
     April.

3.   THE FISHERY
     Current situation
     Recorded annual SEF trawl catches ranged between 170 t to 290 t during 1986 to 1996 but
     were notably lower in recent years. The 1998 SEF2 landed weight of John dory was 127 t
     (115 t in Commonwealth waters and 12 t in State waters), which was 43% of the allocated
     TAC of 296 t. Landings in 1998 were 19% higher than the record low landings in1997
     (103 t), discontinuing a downward trend since 1994. The 1999 TAC remained at 240 t,
     with the allocated TAC being 287 t.

     Through the area of the SEF, John dory are taken by a wide range of fishing techniques.
     Catches outside the SEF are significant, particularly north of Barrenjoey Point. Catches by
     non-SEF commercial fishers within the SEF are less significant, with the annual landings
     on the Victorian and Tasmanian databases during 1990 -96 ranging from 1.2-7.9 t and 0-
     0.3 t, respectively. Catches by the SEF Commonwealth non-trawl sector are insignificant.
     Most of the SEF catch (about 80% by weight) is taken in Eastern Sector A, with virtually
     all the remainder from Eastern Sector B. In both sectors, catch rates show little seasonal
     variation.

     Indicative of the fact that John dory is a by-catch of trawling rather than a targeted species,
     trawl catch rates for John dory are low. During the late 1980s catch rates were around 12
     kg/hr (for shots containing John dory). Since then, catch rates have steadily declined to
     around 6 kg/hr in 1997 and 1998. AFMA‘s catch rate performance criterion was triggered
     in 1996, 1997 and again in 1998.

     Catch rates for John dory are generally highest between 150 and 200 m depth, but in
     keeping with its by-catch status the distribution of the catch reflects the distribution of trawl
     effort and the bulk of the trawl catch in Eastern Zones A and B comes from 50-150 m.
     Discarding rates for John dory are usually very low, ranging from 1-4% by weight annually
     off NSW during 1993-98.

     Catch rates rose in both Eastern Zones, discontinuing a decline which began in 1994, and
     again triggered The gross value of recorded landings in 1998 by Commonwealth endorsed
     trawlers was estimated to be $0.6 million, around 40 per cent lower than in 1997. While


     John dory                                                                                           127
     average returns rose in 1998 the rise was not sufficient to offset the significant decline in
     landings.

     NSW trawl fishers noted that the abundance of John dory peaks seasonally in spring and
     autumn. Fishers claim that trawl catches of John dory off NSW are linked with the north-
     south oscillations of the sub-tropical convergence zone. The best catches are made to the
     north of the convergence zone and, with the oscillation of the convergence zone, move
     north during spring and south during autumn. During the port meetings in 1997, operators
     from Eden south indicated that they had generally observed a decline in abundances, but
     operators from Bermagui north reported steady catch rates. It was again highlighted that
     John dory is a bycatch species, and as such, some operators thought it should not be under
     quota. It was generally thought that abundance of John dory had decreased off Eden and
     Lakes Entrance but remained stable further north. Operators in Ulladulla reported steady
     catch rates. Decreases in the southern abundance were believed to be linked to the
     presence of cold water currents in this area.

4.   PREVIOUS ASSESSMENTS
     The TAC for John dory is based on catch history and John dory has been accorded a low
     research priority. The data that exist for this species are almost totally fishery-dependent
     and do not allow a conclusive stock assessment to be made for this species. Biological data
     are sparse. Consequently, SEFAG has not formalised its assessment of this species.

     A previous series of trawl surveys conducted by VFRI estimated that during 1986, John
     dory biomass in eastern Bass Strait varied from 800 t in winter to 2 400 t in autumn.
     However, these estimates are known to be subject to many assumptions (including a
     catchability of 0.5) and could be seriously biased.

     During 1997, a more detailed analysis of John dory CPUE was undertaken. As John dory
     are a dispersed species taken almost exclusively as bycatch, catch rates should not be
     influenced by (John dory) targeting practices. For example; of all the 67 260 SEF shots
     which contained >1 kg John dory during 1986-97, 56.6% caught <50 kg and 97.3% caught
     <100 kg. Targeted shots on aggregated John dory are clearly a rarity, as 99.9% of these
     shots caught <400 kg. Consequently, unstandardised CPUE is probably a better indicator of
     abundance for John dory than it is for species which aggregate, or are targeted regularly.
     Because of the bycatch nature of this species, the use of total bottom time effort can also be
     justified. Virtually all John dory are caught in waters of <200 m depth, so total effort for
     these waters only should be used. Table 1 summarises catch rates for shots containing >1
     kg of John dory and those for total effort/total landings values, for Eastern Zones A and B.

     Table 1. Annual unstandardised catch rates (kg/hr) for all shots containing >1kg John dory
     (U) and for total effort in <200 m depth against total landings (T) in Eastern Zones A and
     B.

             86      87       88      89       90       91      92       93      94       95         96    97    98
     AU      12.4    14.8     13.0    14.1     13.6     12.1    9.5      12.7    12.0     10.4       9.3   6.8   7.5
     AT      7.7     9.1      7.0     8.9      8.4      7.2     6.5      9.0     8.4      6.2        5.4   3.2
     BU      9.9     14.8     15.4    15.5     12.3     13.8    8.6      9.3     7.9      7.4        5.7   4.8   4.1
     BT      2.3     2.9      2.8     3.8      3.5      3.6     2.9      3.3     3.1      2.6        2.2   1.4


     As expected, total effort values are lower than those for shots containing John dory only,
     demonstrating that a significant proportion of shots in <200 m depth did not contain >1 kg
     of retained catch of this species. This difference is more pronounced in Eastern Sector B
     where John dory appear to be more sparsely distributed and less abundant than in Sector A
     and occur in proportionately fewer shots. Therefore, catch rates in Eastern Sector A
     probably provide a more reliable indicator of abundance than elsewhere in the fishery. Both
     sets of catch rates for Eastern A remain more or less constant throughout 1986 to 1994,

     128                                                                         SEF Species Summary 1999
     except a dip in 1992 (the first year of ITQ management) when misreporting is known to be
     of a high order. However, from 1994 onwards both show a significant decline. If the catch
     rate for 1992 is ignored, both catch rates would have triggered AFMA‘s catch rate
     performance criterion in 1995, as well as in 1996 and 1997.

     In the absence of more concise information, it is unclear if this decline in catch rates
     reflects a decline in John dory abundance, or changes in catchability or fishing practices.
     However, it should be noted that the decline cannot be attributed to an increase in effort in
     Eastern Sector A as SEF1 recorded effort in waters <200 m depth has fallen from 23 266
     hrs in 1994 to 22 208 hrs in 1995, 21 839 hrs in 1996 and 16 779 hrs in 1997. Whereas the
     30% effort decrease from 1996 to 1997 in part explains the respective 55% decline in SEF1
     landings for Eastern A, the pronounced drop in catch rates between these years should be
     viewed with concern. The balance of evidence indicates this to be associated with a decline
     in John dory abundance.

5.   1999 UPDATE
     There was no formal assessment of John dory undertaken during 1999. However, 1998
     logbook and ISMP data were incorporated into this summary.

     Catch and effort
     The 1998 SEF2 landed weight of John dory was 127 t (115 t in Commonwealth waters and
     12 t in State waters), which was 43% of the allocated TAC of 296 t. Landings in 1998
     were 19% higher than 1997 landings (103 t), discontinuing a downward trend apparent
     since 1994. The 1999 TAC remained at 240 t, with the allocated TAC being 287 t.

     The 1998 SEF1 landing total for Eastern Sector A had increased to 76.4 t after the lowest
     on record landing in 1997. 1998 landings in Eastern Sector B (24.1 t) were similar to
     those over the past decade. Mean unstandardised catch rates (based only on shots
     containing John dory) continued to decline in 1998 in Eastern Zone B but increased slightly
     in Eastern Zone A. (see below). Catches by Victorian and Tasmanian endorsed vessels
     were negligible at 0.6 t and 0.3 t, respectively.

     Size composition
     In contrast to 1997, when fish <30 cm appeared to be poorly represented, there was
     evidence of a large cohort of smaller fish of around 20 cm off the NSW coast during 1998.
     This lead to a bimodal distribution, with a second mode of larger fish around 30 cm. The
     cohort of younger fish were not apparent further south in Eastern Zone B, but sample sizes
     were quite small.

     Discard rates
     There are generally low levels of discarding of John dory along the NSW coast. Overall,
     only 3.0% (by weight) of the catch of John dory was discarded in 1997, similar to previous
     years. During 1998, discarding in ports north of Eden were less than 1%. Discarding rates
     around Eden and Lakes Entrance, however, were between 5 and 10%. Although there were
     no data available from the ISMP on the size range of these discarded fish, given the value
     of john dory, one would expect that they would only be small fish, possibly those from the
     large cohort entering the fishery.

     Port visits
     The 1999 port meetings were held in Tasmania and western Bass Strait and John dory was
     not discussed. During the 1998 port meetings along the east coast, fishers in all ports north
     of Bermagui commented on the decline in John dory landings. Ulladulla fishers attributed
     the decline to the decreasing number of inshore boats, with most remaining vessels fishing
     more in shelf-break, upper-slope waters. Wollongong fishers noted that it was a bad time
     for John dory as the fish were not around. John dory is the most valuable species in terms
     of market price and it largely drives inshore fishing. Consequently, the decrease in John
     dory catches has seen a decrease in inshore fishing. What fish were caught on inshore
     grounds contained a proportion of unusually large fish. Whereas they are primarily caught



     John dory                                                                                       129
     as bycatch, they can be targeted at times. Sydney fishers noted that 1997 had been a poor
     year for John dory, whereas 1996 had been a good one.

     Prices
     John dory are one of the highest priced fish species taken in the SEF. The gross value of
     recorded landings of John dory in 1998 was estimated to be about $1.03 million. In 1998,
     prices for John dory averaged $5.62/kg on the Sydney Fish Market, which is lower than
     1997 ($8.70). Melbourne prices were lower than those in Sydney, averaging $3.60/kg.

     Uncertainties in assessment
     Little is known of the basic biological parameters (such as size-at-age, age-at-maturity,
     growth, mortality) for John Dory. The absence of such information essentially impairs
     assessment, which is totally reliant on logbook and SEF2 data, together with ISMP size
     composition data.

6.   IMPLICATIONS FOR MANAGEMENT
     The mean unstandardised catch rates for 1996 and 1997 (and probably 1995) have
     triggered AFMA‘s catch rate performance criterion. Part of the overall decline in SEF catch
     rates may be attributable to the ongoing increase in effort in Eastern Sector B. However,
     catch rates in Eastern Sector A (which usually supplies 80% of the total landed weight)
     have fallen significantly since 1994, particularly from 1996 to 1997, despite a decrease in
     fishing effort. The declining catch rate is probably associated with declining abundance.
     This apparent decline in abundance is probably environmentally driven and the reduced
     representation of smaller (<30 cm) in the catch suggests that lower than average cohorts
     may be entering the fishery. Trawl effort in Eastern Sector A waters of <200 m depth, from
     which the bulk of the SEF catch is taken, has exhibited a steady decline since 1994 and
     increased fishing pressure cannot be held primarily responsible for the decline. SETMAC
     has given a low research priority to this species because it constitutes a low volume fishery
     which is apparently stable. However, catch rates continue to decline and consideration
     should be given to raising the priority for this species, which is of importance to NSW
     based fishers.

     John dory is largely taken as a by-catch of fishing for other shelf species. Thus, the size of
     the John dory catch is largely dependent upon the total amount of fishing effort directed
     towards the depth strata occupied by John dory. Because of the by-catch nature of the
     fishery, several industry members have stated that John dory should be removed from the
     list of quota species. These 1996 comments were probably prompted by the SEF
     Restructuring Taskforce Report which advocated such a removal. However, because of the
     bycatch nature of the fishery the important fact is; That it is extremely unlikely that
     changing the TAC for this species can achieve a management objective of changing the
     total catch (i.e. fishing mortality).

     A significant proportion of John dory landings in south-eastern Australia comes from non-
     SEF fisheries, particularly the trawl fishery north of Barrenjoey, and John dory are also
     taken by the recreational fishery. The extent of these fisheries and their effect upon the
     John dory population(s) within the SEF area are unknown.

7.   RESEARCH NEEDS
     Ongoing monitoring of SEF catch and effort trends through SEF1 and SEF2 returns,
     together with ISMP data on discard rates and size in the catch should allow a time series to
     be developed which could eventually provide the basis of a more definitive stock
     assessment. Catches by non-trawl operators in the SEF and non-SEF catches north of
     Barrenjoey Pt should also be monitored.

     Size/age monitoring should be given a higher priority and ageing validation sought,
     particularly if catch rates continue to decline.




     130                                                                         SEF Species Summary 1999
The biology of John dory in Australia is poorly understood and life-history study is needed.
(most cost effective option; a post-graduate scholarship study?).




John dory                                                                                      131
                       300                                                                                  actual TAC
Total catch (tonnes)




                                                                                                            approved TAC
                       200



                       100



                        0
                                                   1992        1993    1994    1995   1996    1997        1998

                                                                               Year

                   Figure I Total annual verified catches of John dory calculated from the quota monitoring system
                           (SEF2), and actual and approved total allowable catches (TAC)




                                                  16
                                                  14
                         av. catch rate (kg/hr)




                                                  12
                                                  10
                                                  8

                                                  6
                                                  4
                                                  2
                                                  0
                                                       85 86   87 88   89 90   91 92 93   94 95   96 97     98 99

                   Figure II Average annual unstandardised catch rates of John dory




                   132                                                                                SEF Species Summary 1999
Appendix A.1 : John dory recorded commercial catch history within the SEF area (tonnes)


                                      Commonwealth Records                                              State Records
                        TAC                   Retained Catch                                           Retained Catch




                                                                                                                                                        discarded catch 3
                                                                                                                                     catch within the
                                       Commonwealth




                                                                                                                                     Estimated total
                                                      SEF 2 State




                                                                                                                                                           Estimated
                                                                                                                                        SEF area2
                          Allocated




                                                        Waters
               Agreed




                                                                    SEF 1




                                                                                    Total1
                                                                            Other
                                          SEF2




                                                                                                 NSW
   Year




                                                                                                                    Tas


                                                                                                                            S.A.
                                                                                                          Vic
  1971                                                                                          270
  1972                                                                                          410
  1973                                                                                          450
  1974                                                                                          240
  1975                                                                                          260
  1976                                                                                          210
  1977                                                                                          290
  1978                                                                                          230
  1979                                                                                          230
  1980                                                                                          260
  1981                                                                                          220
  1982                                                                                          260
                                                      SEF not Established
  1983                                                                                          270
  1984                                                                       214    214         46                                            260
  1985                                                                       202    202         129                                           331
  1986                                                                231    237    237         132                                           369
  1987                                                                205    229    229          *              4                             233
  1988                                                                181    225    225         94              3                             322
  1989                                                                216    258    258          ?              5                             263
  1990                                                                167           167          ?              3   <1                        170
  1991                                                                169           169          ?              6   <1                        175
  1992        240         243                95 60                    130           155          ?              1                             156
  1993        240         251               112 152                   236           264          ?              2                             266
  1994        240         263               128 164                   267           292          ?              8   <1                        300
  1995        240         275               120 88                    185           208          ?              3   <1                        211
  1996        240         292               136 51                    158           187          ?              1   <1                        188
  1997        240         294                90 13                     87           103          ?              ?   <1                        104
  1998        240         296               115 12                    106           127          ?              ?   <1

  Commonwealth records:                                                                      State records:
          1984 - 1989 verified catch history                                                     1970/71 - 1983/84 NSW landings (SFM fin/yr)
          1990 - 1991 SEF Logbook                                                                1984 - 1988 difference between SFM and SEF
          1992 - 1998 AFMA quota monitoring unit                                                            catch
                                                                                                 * change in accounting year for NSW FMA




  1.   Total of shaded cells                                                                     Abbreviations:
  2.   Estimated by Totaling Commonwealth and State records                                           N/A = Not Applicable
  3    Estimated from the SMP                                                                         ND = No Data Available
                                                                                                       ? = Available data not received




John dory                                                                                                                                                              133
134   SEF Species Summary 1999
      LING
1. AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
      Objectives
      Ongoing
 1.   To ensure that the ling resource is utilised in a manner consistent with the principles of ecologically sustainable
      development.


      Immediate objectives

 2.   To maintain the recruited biomass at the 1995 level
 3.   To manage ling as a multi-sector fishery
 4.   To maximise the economic efficiency of the ling fishery.
 5.   To implement effective and efficient fisheries management on behalf of the Commonwealth.

      Strategies
      The above objectives will be achieved by:
 1.     setting a TAC (including trawl and non-trawl sectors) for the Commonwealth managed portion of the fishery
        that:
         maintains catch per unit effort (CPUE) at or above its lowest annual average level from 1986 to 1994
        (objectives 1,2 & 3)
 2.     managing all sectors of the ling fishery in a complementary manner
        (objectives 1 & 5)
 3.     prioritising ling research in relation to other SEF quota species:
         SETMAC has given a high research priority rating to this species
        (objectives 1, 2, 3, 4 & 5)
 4.     data collection
          (a)   determine recent and current annual catches by each sector of the fishery, including changes in
                patterns of catch (catch, catch rates, shifts in effort and changes in fishing practices)
          (b)          obtain representative length/age distributions of commercial catches
          (c)          by 1999/00 obtain estimates of:
                   the recruited biomass at the onset of significant commercial fishing (year to be determined)
                 the recruited biomass of the fishery in 1995
             (objectives 1,2 & 3)
 5.     undertaking economic research on the fishery to calculate GVP and determinants of market prices for ling
        (objective 4)

      Performance indicators

 1.     That the current annual CPUE is above its lowest annual average level from 1986 to 1994
        (strategy 1)
 2.     That all sectors of the fishery are managed in a complementary manner
        (strategy 2)
 3.     Data relevant to the annual assessment of ling has been collected and analysed, and considered by
        SEFAG
        (strategies 3, 4 & 5
 4.     The actual trawl catch relative to the trawl TAC
        (strategy 1)




      Ling                                                                                                         135
2.    STOCK STRUCTURE AND LIFE HISTORY
      A CSIRO study of ling stock structure off southern Australia is currently under way. There is some
      evidence, using fin ray and vertebral counts, proportional body measurements and allozyme
      electrophoresis, that the fishery does not consist of a single homogeneous stock. This is being investigated
      further during the current year using more sophisticated genetic techniques. At this time, a common SEF
      stock is assumed for management purposes. However, data from the fisheries east and west of Bass Strait
      are being analysed separately for stock assessment purposes. The life history of ling is poorly understood.
      Spawning is thought to occur in winter-spring, beginning in September. Industry has reported three
      known spawning areas where fish appear to aggregate and move into shallower waters. These are off
      western Tasmania (Strahan), Mount Everard, Victoria and Gabo Island. Little is known of early life
      history. Recent ageing of fish sampled from Australian waters indicates a maximum age of about 30
      years. Females grow faster and reach a greater size than males. In New Zealand, both sexes reach maturity
      at ages 7 to 8 years and natural mortality (M) is estimated to be 0.18 (Annala et al 1999). Total mortality
      (Z) estimates from research trawl samples taken early in the Eastern Sector A/B fishery (1976-82) ranged
      from 0.254 to 0.345.

3.   THE FISHERY
     Current situation
     The allocated TAC for ling has progressively risen from 700 t in 1992, 809 t in 1993, 995 t in 1994, 1524
     t in 1995, 1604 in 1996, 1734 in 1997, 2191 t in 1998 to 2611 t in 1999. Since 1998, this TAC has
     covered both sectors. In 1999, the recommended TACs for the trawl and non-trawl sectors were 2095 t
     and 305 t, respectively. In 1998, SEF2 recorded trawl landings totalled 1692 t (1679 t Commonwealth
     waters, 13 t State waters), slightly less than in 1997 (1756 t). Non-trawl catches increased from 1992
     onwards, but have stabilised since the introduction of ITQ management. Non-trawl totals for 1998 were
     as follows; Commonwealth non-trawl 202 t, Tasmania 6 t, Victoria <1 t and NSW ?? t. The total 1998
     catch by all methods (probably around 1950 t, allowing for about 50 t NSW) was about 5% less than the
     respective 1997 total. 1998 SEF1 trawl catches in Eastern Sector A (433 t) and the West Tasmania Zone
     (355 t) were the highest on record, although catches from Eastern Sector B (-8.7%) and the Western Zone
     (-12.5%) fell slightly from 1997. The discard rate of 6.2% by weight across the fishery was similar to that
     in 1997 (6.6%).

      The gross value of recorded landings of trawl caught ling in 1998 was estimated to be about $A5.6
      million. The average return to operators (net of marketing charges) in 1998 was estimated to be
      $3.33/kg, 14% higher than in 1997. Assuming no price differential between trawl and non-trawl caught
      fish, the total gross value of the 1998 ling catch was about A$6.5 million, making this species the third
      most valuable in the SEF. Australia imports substantial quantities of ling from New Zealand. In 1998,
      XX t (product weight) were imported of which most (XX t) was in frozen fillet form. Ling imports from
      New Zealand have been increasing since 1991, when 354 t were imported.

      The greatest trawl catches of ling were traditionally taken in Eastern Sectors A and B, with lesser amounts
      taken off the west coast of Tasmania and to the west of Bass Strait. However, since 1994, landings in the
      west have increased significantly, particularly from the West Tasmania Zone. Mean annual
      unstandardised and standardised trawl catch rates for the period 1986 to 1998 have remained
      comparatively stable across the whole fishery. However, there were some marked differences in the
      seasonality of catches between areas, with catch rates in the Eastern Sectors peaking in early winter (May-
      June) and those off west Tasmania showing a pronounced peak in late winter/spring (August-November).

     Port Meetings
     Increased trawl catches in ling over recent years have resulted mainly from increased market demand and
     consequent targeting, although only minor modifications have been made to the gear. At the 1998 port
     meetings along the east coast, operators were again generally optimistic about the status of the ling stock,
     although some divergence of opinion on 1997 catches was evident. Eden operators thought 1997 had
     been a comparatively poor year, whereas Wollongong operators said 1997 had been a good year.
     Operators had previously commented that the smaller size composition of trawl catches when compared
     to those by the hook fishery was probably because large fish were ‗too quick‘ for trawls. Many operators
     had noted that the scarcity of ling quota was possibly causing discarding, but ISMP data again indicated
     that ling discards were of a low order (6.6% by weight) in 1997. Whereas trawl operators had previously
     been concerned about apparent increases in non-trawl catches, the move to ‗global‘ ITQ management in


     136                                                                        SEF Species Summary 1999
           1998 had made this less of an issue. The 1999 port meetings covered western Bass Strait and Tasmania
           (Prince & Baelde 1999). Portland operators noted that ling and spotted warehou occur in the same depths
           and are often caught together. They further noted that ling abundance appeared to have decreased slightly
           in 1998/99 (1998 landings reflect this). Tasmanian trawl operators noted that whereas ling do not
           aggregate as such, they can be targeted by using longer tows on the right grounds at the right time. Best
           trawl catches occur between October and December. Catch rates by the only automatic long-liner in the
           fishery have been stable overall, although the abundance of ling off Macquarie Harbour seems to have
           increased. Ling appear to be more catchable by long-line during two periods; they first come on to the
           grounds in August-September, then catches decrease until the fish return in summer (January-March). The
           same ‗types‘ of fish (similar size and abundance) are caught during these two periods.


     4.    PREVIOUS ASSESSMENTS
          A FRDC funded Ling Stock Assessment Workshop was held at VFRI, Queenscliff, 5-7 June 1995. SEF
          logbook catch and effort statistics were examined for the period 1986 to 1994. Only those shots catching ling
          were used to calculate catch rates. Data were examined separately for each major area in the fishery and by
          season. SMP data were examined to determine discard rates. Size composition and ageing data collected since
          the late 1970s were used to examine changes in age composition and mortality rates were estimated from catch
          curve analysis. Revised growth parameters were derived.

          Unlike the previous Australian growth study that indicated differences with New Zealand, revised growth
          curves were consistent with New Zealand studies and ageing methods and interpretation were identical. The
          maximum age in Australian samples was 28 years. Trawl catches were dominated by 3 to 6 year olds, except
          for catches from the west coast of Tasmania. Demersal longline catches contained relatively more larger, older
          fish.

          There was a marked decline in the proportion of older fish in recent samples from Eden and Ulladulla and an
          associated increase in the estimate of total mortality compared to data from the mid to late 1980s. Results
          from all years suggested that natural mortality was higher for ages 3-10 (approx. 0.3) than for older fish
          (approx. 0.1).

          The major uncertainty concerned estimates of high mortality rates derived from the age composition of fish
          landed at Eden and Ulladulla. This was inconsistent with catch rates, which had remained comparatively
          stable. Also, industry reported considerable discarding of small ling, but this was not evident in SMP data. It
          was unclear if improved catches were attributable to changes in fish abundance, catchability, improved
          targeting practices, or a combination of all these factors. Stock status was uncertain. Little was known about
          the size of the resource and the possible implications of spatial structuring could not be adequately addressed.

          There were no formal 1996, 1997 and 1998 assessments, with logbook and SMP data for 1995, 1996 and 1997
          being examined and incorporated into the respective updates. Trawl catch rates over this period remained
          comparatively stable despite significant increases in annual landings following TAC increases.
          Surveys by FRV Kapala ( Andrew et al 1997) indicated that ling abundance between Sydney and Gabo
          Island had not changed significantly between 1976/77 and 1996/97. This supported the evidence provided
          by the comparatively constant catch rates between 1986 and 1997.

5.        1999 ASSESSMENT
          An ARF-funded ling workshop was held at AFMA on December 8-9 1998 (Tilzey 1999). More recent
          catch rate analyses incorporated data for the full 1998 year. The workshop decided to initially analyse data
          for the trawl fisheries east and west of Bass Strait independently, pending the final results from the ongoing
          CSIRO stock structure study.
          Catch and effort
          SEF1 data
          The 1998 trawl catches from Eastern Sector A (433 t) and the West Tasmania zone (355 t) were the highest
          on record, whereas catches from Eastern Sector B ( 357 t) and the Western zone (210 t) were slightly lower
          than those for 1997. The respective totals comprised 31.3%, 25.6%, 25.8% and 15.2% by weight of the
          1998 SEF1 total of 1387 t. The overall 1998 landings total, from all sectors and SEF waters (SEF2 and


          Ling                                                                                                      137
State records), of around 1950 t was about 5% less than in 1997. The estimated 1998 discard rate of 6.2%
by weight across the fishery was again comparatively low and similar to that in 1997 (6.6%).

Mean SEF annual unstandardised trawl catch rates for shots containing 1 kg or more of ling over the period
1986-98 have ranged from 28.3 kg/hr in 1992 (the first year of ITQ management, in which SEF1
misreporting was comparatively high) to 40.1 kg/hr in 1987. From 1993 to 1998, mean SEF annual catch
rates were very stable, ranging from 31.3 to 36.2 kg/hr. This comparative stability occurred in all statistical
zones. In most years the highest catch rates have been in the West Tasmania zone. Comparatively few ling
are caught in the East Tasmania zone, but annual mean catch rates are similar to those for the Eastern
Sectors.
Following the workshop, Haddon (1999) derived standardised indices of relative abundance. Initially, two
fisheries were recognised, a western fishery made up of the catches from zones 40, 50, and 60, plus an
eastern fishery made up of the catches from zones 10, 20, and 30. In zones 10 and 20 there appeared to be a
relatively shallow water fishery, plus a more typical deeper water fishery. Only vessels with more than two
years of data were included in the analyses. A further restriction was to limit the analyses to reported
catches of greater than 30 kg. The characterisation of the data illustrated the very large differences between
months, years, and depths that exist in the data. This suggested that the standardisation was very necessary.

The final model used for the western fishery was: Ln(CE) = Constant + Year + Month + Zone + Depth +
Vessel which described 24 % of the catch-effort variation. In the eastern fishery the best fitting model was:
Ln(CE) = Constant + Year + Month + Depth + Vessel + Depth x Month, which successfully described 21
% of the catch-effort variation.

The main effect of the standardisation in the west was to reduce the severity of the apparent fluctuations in
real catch-rates through time. Also, there appeared to have been a steady increase in catch rates since 1992.
In the eastern fishery the standardisation showed little visible difference over the simple geometric means.
There appeared to have been a slow and steady increase in catch rates since the fishery started recording
data. Whether this rise is enough to be biologically significant is debatable. For both fisheries this analysis
of CPUE provided no negative impressions concerning the status of the fishery. Differences between the
localised components of the ling fishery need to be further investigated in terms of when they are active and
with which species they tend to be caught.

The SEF1 database contains only 457 shots containing ling catches of a tonne or more, indicating that ling
generally do not aggregate and are not highly targetable.
Catch composition
Size: Comparisons between the length frequencies collected by the SMP over the period 1993 to 1996
(Liggins 1997) and 1997/98 (ISMP) show no trends. Catches at Ulladulla and Eden peaked at around 55
cm. Catches from Lakes Entrance and Portland contained significantly more larger (>65 cm) fish.
Length frequency data from the FRV Kapala surveys showed a significant drop in the representation of
larger (>70 cm) fish between 1976/77 and 1996/97. This was apparent in most areas and depth zones. Mean
length (TL) declined from 77.0 cm in 1976/77 to 69.6 cm in 1979/81 and 58.6 cm in 1996/97.
Age: Following the ageing of archived 1979 otoliths, the calculated age compositions of Kapala catches
(using the 1979 age-length key) made in 1976/77, 1979, 1980, 1981, and 1982 were all dominated by 3 and
4 year-olds, but by 1982 the catch contained comparatively few fish aged 5 years or more. Samples from
the SMP/ISMP showed 2 year-olds to dominate the trawl catch off NSW during 1994-97, followed by
declining representation of 3 to 5 year-olds. In eastern Bass Strait catches, 2-5 year-olds dominated in
1994-96, although sample sizes were small. In western Bass Strait catches during 1994-97, 2-4 year-olds
were most abundant, with 5-6 year-olds also being comparatively well represented. Comparatively very few
fish aged over 6 years occurred in all trawl catch samples, except those from off western Tasmania
(1993/94) where fish aged 7-13 years comprised a significant portion. A 1993 sample from automatic long-
line catches off western Tasmania showed these to contain a greater proportion of larger, older (up to 27
years) fish than trawl catches from this area. The workshop noted that obtaining more recent size/age data
for long-line catches should be given a high priority.
The mortality estimate (Z) derived from the 1979 aged sample was 0.254. The Bertalanffy growth
parameters derived from this sample confirmed that females grow faster and live longer than males.


138                                                                          SEF Species Summary 1999
     Females        Linf 126.0 cm         K 0.151        Tzero -0.791
     Males                112.5              0.167                -0.769
     Modelling
     Data requirements for modelling were discussed in detail at the workshop. It was stressed that the fishery
     contained multiple sectors, including west and east trawl and non-trawl, and gear selectivity was a major
     issue. Initial modelling will proceed through 1999/00, primarily based on the procedures used by Punt and
     Japp (1994). Harvest strategies are also being examined.
     Available stock assessment data for ling are currently being compiled by Furlani (1999).

6.    IMPLICATIONS FOR MANAGEMENT
     Unstandardised and standardised ling trawl catch rates were comparatively stable from 1986 to 1998
     suggesting that ling abundance did not significantly alter over this period. In recent years, annual SEF trawl
     landings have risen as a result of higher TACs and consequent increased targeting, particularly west of Bass
     Strait. Non-trawl catches have largely stabilised after increasing sharply during 1992-93 and are now limited
     by a global TAC. The 1998 landed catch from all sectors was around 1950 t (CHECK), the second highest on
     record. Whereas present catches are much greater than historic levels, trawl catch rates suggest that abundance
     has not decreased. A recent fishery-independent trawl survey off southern NSW also indicates that ling
     abundance has not decreased between 1976/77 and 1996/97. However, the impact of increased catches is
     unknown and requires a more rigorous assessment than is possible through evaluation of fishery-dependent
     data alone. A preliminary model is currently being developed for assessment purposes

     Current stock structure and status are still uncertain. Despite the apparent stability of the fishery, estimates of
     recent mortality rates derived from the age representation in catches from the eastern sector of the fishery were
     high. Comparatively little is known about the size and spatial structuring of the resource. A CSIRO study of
     stock structure is currently under way and initial results suggest that there may be some structuring within the
     SEF. If this proves to be so, separate stocks may require individual management.

     The bulk of the trawl catch is comprised of fish aged six years or less, whereas the hook sector takes older,
     larger fish. Because of this difference in gear selectivity, the biological implications of a possible shift in effort
     between the trawl and non-trawl sectors need to be examined, particularly as quota transferability between
     sectors is already occurring. The model(s) currently being developed and the harvest strategy study should
     address this issue.

7.    RESEARCH NEEDS
     Ling has been accorded a high research priority by the SETMAC Research sub-committee. The highest
     priorities are:
      to continue obtaining representative age-size data from both trawl and non-trawl sectors.
      undertake a more rigorous analysis of SEF1 logbook data to examine detailed spatial and temporal
       patterns of ling catches and interactions with other SEF species.
      A project on the biology of ling and their behavioural factors, which are poorly understood and limit
       interpretation of trends in catch rates and size composition.
      Evaluation of harvest strategies for ling which are often caught as a component of a targeted suite of
       species, or as by-catch; and are a multi-sector species. This should also include assessment of gear
       selectivity factors and their possible effects on the fishery as a whole if effort shifts between sectors.
      Stock structure is still unknown, but a CSIRO study is addressing this issue.

REFERENCES
     Andrew, N.L., Graham, K.J., Hodgson, K.E. & Gordon, G.N.G. (1997) Changes after twenty years in
     relative abundance and size composition of commercial fishes caught during fishery independent surveys
     on SEF trawl grounds. Final Report to FRDC. Project no.96/139. December 1997.
     Annala, J.H., Sullivan, K.J. and O‘Brien, C.J. (1999) Report from the Fishery Assessment Plenary, April
     1999: stock assessments and yield estimates. Ministry of Fisheries, N. Z. 430pp.



     Ling                                                                                                           139
Furlani, D. (1999) Summary of fishery and survey data for pink ling (Genypterus blacodes) in the
SEF.Draft report to SEFAG
Haddon, M. (1999) Standardization of catch/effort data from the south-east ling fishery. SEFAG Working
Group Paper. 16pp.
Liggins, G.W. (1997) Integrated Scientific Monitoring Program for the SEF in 1996 (NSW component).
Report to AFMA. May 1997.
Prince, J. and Baelde, P. (1999) Report to the SEFAG on the 1999 tour of the SEF ports between
Beachport and Hobart.
Punt, A.E. and Japp, D.W. (1994) Stock assessment of the kingklip Genypterus capensis off South Africa.
S. Afr. J. mar. Sci. 14: 133-149.
Tilzey, R.D.J. (1999) Report on the Ling Workshop held at AFMA on 8-9 December 1998. SEFAG
Working Group Paper.




140                                                                      SEF Species Summary 1999
                           2000                                                                        actual TAC
                                                                                                                    approved TAC
    Total catch (tonnes)
                           1600

                           1200


                           800

                           400

                             0
                                                                1992       1993   1994   1995   1996      1997      1998

                                                                                         Year



Figure I Total annual verified trawl catches of ling calculated from the quota
         monitoring system (SEF2), and actual and approved total allowable catches
         (TAC)




                                                               1.2000
                             standardised catch rate (kg/hr)




                                                               1.0000

                                                               0.8000

                                                               0.6000

                                                               0.4000

                                                               0.2000

                                                               0.0000
                                                                        85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Figure II Average annual standardised trawl catch rate of ling




Ling                                                                                                                               141
              Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) - Ling


                                   Commonwealth Records                                               State Records
                Tr TAC                     Retained Catch                                            Retained Catch




                                                                                                                                      catch within SEF



                                                                                                                                                         discarded catch1
                                   Commonwealth




                                                                                                                                       Estimated total
                                                  SEF 2 State




                                                                                                                                                            Estimated
                       Allocated




                                                    Waters
              Agreed




                                                                                Total4
                                                                SEF 1


                                                                        Other
                                      SEF2




                                                                                              NSW




                                                                                                                                            area3
 Year




                                                                                                                  Tas
                                                                                                        Vic
1976
1977
1978
1979
1980
1981
1982
                                                   SEF not Established
1983
1984                                                                      762    762            11                                            773
1985                                                                      680    680            39                  15                        734
1986                                                             679      677    677            50                  36                        763
1987                                                             765      838    838            51        29         8                        926
1988                                                             567      717    717            50        43        10                        820
1989                                                             672      760    760            45        57        13                        875
1990                                                             668             668            24        39        19                        750
1991                                                             735             735            21        47        14                        817
1992           700      780            622              33       567             655            36       153        85                        929
1993           800      809            917             119       883            1036            36       254       325                       1651
1994          1000      995            925             122       895            1047           111        74       311                       1543
1995          1500     1523           1272             138      1209            1410           131       121       163                       1825
1996          1500     1604           1433              16      1231            1449            58       139       394                       2040
1997          1600     1734           1735              21      1445            1756             ?        <1       226      224a
1998          1921     1963           1679              13      1394            1692             ?         ?         6      202a

Commonwealth records:                                                                    State records:
        1984 - 1989 verified catch history                                                    1984 - 96 NSW hook and trawl fishery1
        1990 - 1991 SEF Logbook                                                               1986 - 97 Victorian MAFRI
        1992 - 1998 AFMA quota monitoring unit                                                1985 - 98 Tasmanian DPI
                                                                                         a C/W non-trawl quota monitoring unit

1.      Estimated from the SMP                                                                Abbreviations:
2.      State location                                                                             N/A = Not Applicable
3       Estimated by totaling Commonwealth and State records.                                      ND = No Data Available
4       Total of shaded cells                                                                       ? = Available data not received




              142                                                                                               SEF Species Summary 1999
Mirror Dory   143
     MIRROR DORY

1.    AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
      Objectives
      Ongoing
1.    To ensure that the mirror dory resource is utilised in a manner consistent with the principles
      of ecologically sustainable development.

      Immediate objective
2.    To encourage the controlled utilisation of mirror dory in areas of the SEF other than those
      associated with the eastern gemfish spawning run. This objective is believed appropriate
      since there is little concern regarding the sustainability of mirror dory catches, which are
      well below the TAC, but serious concern over the status of the eastern gemfish resource
      which is associated with mirror dory.

3.    To maximise the economic efficiency of all sectors of the mirror dory fishery.

4.    To implement effective and efficient fisheries management on behalf of the
      Commonwealth.

      Strategies
      In reading these strategies it should be noted that a significant proportion of the mirror dory
      catch was traditionally taken with eastern gemfish. Eastern gemfish currently has a zero
      TAC and SEF operators are endeavouring to avoid gemfish which in turn may affect mirror
      dory catches and catch rates across the whole fishery. Parameters for standardised CPUE
      analysis can, however, be written to account for changes to fishing practices. Catch rates
      can still, therefore, be used to give an indication of trends in the status of mirror dory.

      The above objectives will be achieved by:
1.    setting a TAC for the Commonwealth managed portion of the fishery
        maintains the catch per unit effort (CPUE) above its lowest annual average level from
           1986 to 1994, taking into account spatial and temporal factors and changes to fishing
           practices
       [Note that the TAC currently only applies to the trawl sector of the fishery within the SEF,
      excluding the southern remote zone] (Objective 1)

2.    managing all sectors of the mirror dory fishery in a complementary manner
       this includes all sections of the Commonwealth fishery and those remaining under State
         jurisdiction (Objectives 1 & 4)

3.    prioritising mirror dory research in relation to other SEF quota species:
        SETMAC has given a medium research priority rating to this species
      (Objectives 1,2, 3 & 4)

4.     data collection
       (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing
           practices
      (ii) monitoring of length distributions in commercial catches and undertake ageing as
     required

5.    undertake economic research on the fishery to calculate GVP and monitor market prices for
      mirror dory (Objective 3)

     Performance indicators
1.    The actual trawl catch relative to the TAC and,
       that the current annual 'standardised' CPUE for mirror dory is above its lowest annual
           average level from 1986 to 1994 (Strategy 1)


     144                                                                          SEF Species Summary 1999
2.   All sectors of the fishery (Commonwealth and State) are being managed in a
     complementary manner (Strategy 2)

3.   Data relevant to the annual assessment of mirror dory has been collected and analysed, and
     considered by the SEFAG (Strategies 4 & 5)



2.   STOCK STRUCTURE AND LIFE HISTORY
     Mirror dory (Zenopsis nebulosis) are distributed throughout the continental shelf and upper
     slope waters off southern Australia from Broken Bay in New South Wales to the North
     West Shelf off Western Australia. Mirror dory are also recorded from New Zealand and
     Japan. Nothing is known of mirror dory stock structure within Australia. For management
     purposes, a single stock is assumed for the SEF fishery. There is little published
     information about mirror dory and relatively little is known of their biology.
     Mirror dory are probably relatively solitary fish that prey on fish, crustaceans and molluscs.
     They aggregate and spawn between May and September off central and southern New
     South Wales with several other SEF species, including gemfish; behaviour which
     presumably takes advantage of the predictable winter/spring upwelling in that area which
     results in seasonal plankton blooms.
     Length-frequency distributions of mirror dory are extremely variable between trawl shots
     and years suggesting that recruitment is variable year-to-year, and that there is strong size
     structuring in their distribution. Mirror dory appear to be fully recruited to the trawl fishery
     and also become sexually mature between 30-40 cm in total length which, based on current
     unvalidated ageing, corresponds to an age of 4-7 years . Age estimates from whole otoliths
     ranged from 3 years for a male fish of 25.0 cm to 12 years for a female fish of 63.6 cm TL.

3.   THE FISHERY
     Current situation
     In recent years, mirror dory catches have been depressed by the downturn in the eastern
     gemfish fishery, as the bulk of the dory catch used to be taken as a bycatch of winter
     gemfish targeting. In 1992, a TAC of 600 t was introduced for mirror dory and was
     subsequently increased to 800 t in 1993. Since 1992, recorded catches have risen, largely
     attributed to an increase in effort in the 400 - 450 m depth stratum of Eastern Sector A. In
     contrast to the pre-1990 period the 400 - 450 m depth strata is now the most important
     depth strata in terms of recorded catch of mirror dory.
     The 1998 SEF2 recorded catch of mirror dory was 426 t (413 t in Commonwealth waters
     and 13 t in State waters), which was 44% of the allocated TAC of 962 t. Landings in 1998
     were 22% lower than the 1997 landings of 546 t. The lower catch probably resulted from
     the reduced TAC for eastern gemfish of 300 t in contrast to 1997, when a ‗once-off‘ TAC
     of 1000 t for eastern gemfish allowed mirror dory to be more freely targeted within the
     winter gemfish depth zone. Since 1996, catches of mirror dory have been boosted by
     increased catches to the west of Bass Strait, which comprise about 34% of the total catch.
     The 1999 agreed TAC remained at 800 t, with the actual TAC being 959 t.
     In 1996, mean unstandardised catch rates (based only on shots containing mirror dory)
     dropped to just below 20gk/hr for the first time and triggered AFMA‘s catch rate
     performance criterion. Catch rates have since remained stable around this level. However,
     the influence of the gemfish TAC on mirror dory catch rates limits their use as an index of
     abundance. Since the 1980s, aggregate catch rates have declined from around 40 kg/hr to
     20kg/hr in Eastern Sector A, and from around 25 kg/hr to 15 kg/hr in Eastern Sector B.
     The gross value of recording landings of mirror dory by Commonwealth trawlers in 1998
     was estimated to be nearly $1 million.




     Mirror Dory                                                                                        145
4.   PREVIOUS ASSESSMENTS
     The biomass of mirror dory in eastern Bass Strait during 1986, as estimated by a stratified
     random trawl survey, ranged from a minimum of 100 t in spring to a maximum of 900 t in
     winter. However, these estimates are not considered reliable.
     No yield estimates can be made for mirror dory because of the paucity of biological
     information and the lack of an adequate index of abundance. The TAC for mirror dory is
     based on catch history only.
     Ageing data have indicated mirror dory to be relatively short lived, fast growing fish. Since
     the 1980s, aggregate catch rates have declined from around 40 kg/hr to 20kg/hr in Eastern
     Sector A and from around 25 kg/hr to 15 kg/hr in Eastern Sector B. This decline in raw
     catch rate triggered AFMA's catch rate performance criterion in 1995. However these
     trends were difficult to interpret because mirror dory were being fished approximately 50m
     deeper than before to minimise the by-catch of gemfish.

5.   1999 ASSESSMENT
     There was no formal assessment of mirror dory undertaken during 1999. However, 1998
     logbook and ISMP data were incorporated into this summary.
     Catch and effort
     Historically, about three quarters of the landings of mirror dory were from Eastern Zone A
     and the rest caught in Eastern Zone B. In 1996, this trend changed, with a far greater
     proportion (around 35%) of the catch coming from west of Bass Strait. This continued in
     1997 and 1998, with most of the landings from the eastern zones (42% in Eastern Zone A
     and 16% in Eastern Zone B) but significant landings (34%) of mirror dory from west of
     Bass Strait. Catches during 1998 were slightly lower than the 1997 catch, which was the
     highest recorded catch of mirror dory since 1989. Catches by state endorsed vessels were
     minimal.
     In 1996, mean unstandardised catch rates (based only on shots containing mirror dory)
     dropped to just below 20gk/hr for the first time and triggered AFMA‘s catch rate
     performance criterion. Catch rates have since remained stable around this level. However,
     mirror dory are caught at the same depths as eastern gemfish and catches have been
     strongly influenced by the zero TAC for gemfish. Thus, as an index of abundance, mirror
     dory catch rate figures should be treated with caution.
     Size composition
     The size range of the landed catch of mirror dory along the east coast has remained stable
     over the last decade. The length frequency distributions of the catches range between 15
     and 60 cm with a mode between 30 and 40 cm. However, nearly all fish below 30 cm are
     discarded. To the west of Bass Strait, fish are generally larger, ranging between 40 and 60
     cm with a mode around 45 – 50 cm. In 1997 there was a large cohort of mirror dory
     between 25 and 35 cm in the Western Zone. These were not apparent in 1998 samples.
     Discard rates
     Discarding of mirror dory in the Eastern Zones is generally high, with between 50 and 80
     % by weight being discarded in previous years (Liggins 1996). In most instances, smaller
     fish (< 30 cm) were discarded. During 1997, however, discarding of mirror dory decreased
     significantly. In Eastern Zone A and B discarding fell to 13% and 29% respectively.
     Although catches of mirror dory in the western zones have increased significantly since
     1996, they are comprised of larger fisher and levels of discarding are minimal. High levels
     of discarding continued in eastern Bass Strait (30%) and off the east coast of Tasmania
     (42%) but they were lower than in 1997 (74%).
     During 1998, the overall discard rate of mirror dory was 12%, which equated to about 60 t
     of fish discarded across the SEF.
     Port visits
     At the 1999 port meetings, Industry highlighted that although catches of mirror dory in
     western Bass Strait were down on the previous year, they were still higher than historical
     levels. In previous port meetings on the east coast, Industry continually stress that the co-


     146                                                                         SEF Species Summary 1999
     occurrence of mirror dory and eastern gemfish caused difficulty in filling mirror dory quota
     without exceeding trip limits on gemfish. Thus, the targeting of mirror dory has been
     minimal since the introduction of a zero TAC for eastern gemfish. Increased time is being
     spent fishing deeper than gemfish to maximise catches of ling and mirror dory while
     minimising gemfish catches. Operators in the Eastern Sectors A & B said that although
     mirror dory are normally a winter species, the 1997 winter season was average, but they
     appeared to be relatively abundant during the 1997/98 summer. No concern was raised
     about the status of the stocks. It was reported that mirror dory were not selling well on the
     market.
     Prices
     In 1998, the gross value of recorded landings of mirror dory was estimated to be about
     $0.94 million. Prices for mirror dory averaged $2.00/kg on the Sydney Fish Market, which
     is slightly higher than in Melbourne ($1.70/kg).


6.   IMPLICATIONS FOR MANAGEMENT
     Mirror dory abundance off NSW and NE Victoria peaks during winter in exactly the same
     depth strata (300-449 m) as the winter gemfish spawning run. It should be noted that
     management changes targeted at either of these species will impact both species. From the
     SEF1 returns there appears to be evidence to support industry claims that targeting
     practices changed to accommodate the zero TAC for gemfish. Off NSW, the mirror dory
     catch is now being caught deeper than it was prior to the TAC for gemfish being reduced to
     zero. This makes raw catch and effort data even more difficult to interpret.
     Nevertheless, AFMA‘s catch rate performance criterion has been triggered for the fourth
     year in a row.
     The TAC for mirror dory has been set at the highest historical catch which was taken as a
     by-catch of an unrestricted gemfish catch. Current mirror dory catches are now well below
     this level and it appears unlikely that the TAC will limit landings in the foreseeable future.

7.   RESEARCH NEEDS
     Mirror dory is currently accorded a medium research priority which effectively precludes
     targeted research programs. In accordance with this priority the main research priorities
     should be:
1. The continued collection of a time series of catch and effort data,
2. Data collection by the ISMP to document rates of discarding and the size structure of the
   retained and discarded catch.
3. Opportunistic collection of mirror dory otoliths to provide a snapshot of the age
   composition for future research.
4. Further analysis of SEF1 logbook data to document changing targeting patterns with the
   resumption of fishing for eastern gemfish in 1998 and its effect on mirror dory catches.




     Mirror Dory                                                                                      147
                          1000                                                                              actual TAC
   Total catch (tonnes)

                          800                                                                           approved TAC

                          600

                          400

                          200

                                    0
                                                 1992    1993     1994    1995      1996     1997    1998

                                                                          Year



Figure I Total annual verified catches of mirror dory calculated from the quota
         monitoring system (SEF2), and actual and approved total allowable catches
         (TAC)




                                            90
                                            80
                                            70
                           av. catch rate




                                            60
                                            50
                                            40
                                            30
                                            20
                                            10
                                            0
                                                 85 86   87 88   89 90   91 92 93    94 95   96 97   98 99


Figure II Average annual unstandardised catch rates of mirror dory




148                                                                                            SEF Species Summary 1999
Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Mirror dory


                                    Commonwealth Records                                              State Records
                      TAC                   Retained Catch                                           Retained Catch




                                                                                                                                       catch within SEF



                                                                                                                                                          discarded catch3
                                     Commonwealth




                                                                                                                                        Estimated total
                                                    SEF 2 State




                                                                                                                                                             Estimated
                        Allocated




                                                      Waters
             Agreed




                                                                                  Total1
                                                                  SEF 1


                                                                          Other
                                        SEF2




                                                                                               NSW




                                                                                                                                             area2
 Year




                                                                                                                 Tas


                                                                                                                          S.A.
                                                                                                        Vic
1971                                                                                           40                                                40
1972                                                                                           90                                                90
1973                                                                                          170                                               170
1974                                                                                          200                                               200
1975                                                                                          290                                               290
1976                                                                                          420                                               420
1977                                                                                          580                                               580
1978                                                                                          860                                               860
1979                                                                                          420                                               420
1980                                                                                          290                                               290
1981                                                                                          160                                               160
1982                                                                                          310                                               310
                                                    SEF not Established
1983                                                                                          220                                               220
1984                                                                       241    241           ?                                               241
1985                                                                       377    377           ?                                               377
1986                                                              415      487    487           ?                                               487
1987                                                              476      569    569           ?                                               569
1988                                                              346      483    483           ?         <1                                    483
1989                                                              591      650    650           ?                                               650
1990                                                               296            296           ?               4                               300
1991                                                               246            246           ?               <1                              246
1992        600         700               203               8     167             211           ?         3     <1                              214
1993        800         803               312              19     299             331           ?         4                                     335
1994        800         879               302              20     294             322           ?        <1     <1                              322
1995        800         953               268              12     243             280           ?         1                                     281
1996        800         978               383              20     342             403           ?        <1     <1                              403
1997        800         978               525              21     455             546           ?         ?     <1                              546
1998        800         962               412              13     355             425                           <1

Commonwealth records:                                                                      State records:
        1984 - 1989 verified catch history                                                      1970/71 - 1983/84 NSW landings (SFM fin/yr) most post-
        1990 - 1991 SEF Logbook                                                            85 NSW catches on SEF1/SEF2
        1992 - 1998 AFMA quota monitoring unit                                                  1987 - 96 MAFRI Victoria
                                                                                                1990 - 98 DPI Tasmania

1.   Total of shaded cells.                                                                    Abbreviations:
2.   Estimated by totaling Commonwealth and State records                                           N/A = Not Applicable
3    Estimated from the SMP                                                                         ND = No Data Available
                                                                                                     ? = Available data not received




Mirror Dory                                                                                                                                         149
150   SEF Species Summary 1999
Mirror Dory   151
 OCEAN PERCH

1.         AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
           FOR OCEAN PERCH*
           Since ITQ‘s have been introduced, ocean perch has been considered as a single species
           for SEF management purposes. Actually, the TAC includes two species of the Helicolenus
           genus, namely H. percoides and H. barathri, commonly referred to as ‗inshore‘ ocean
           perch or ‗coral cod‘ and ‗offshore‘ ocean perch respectively. Other Scorpaenid species
           which are similar in appearance are not included in the TAC.

        Objectives
        Ongoing
     1. To ensure that the ocean perch resource is utilised in a manner consistent with the
         principles of ecologically sustainable development.

           Immediate objective
     2.    To ensure that the spawning biomass of ocean perch does not significantly decline below its
           current (1995) level:
             current jurisdictional boundaries and varying approaches to management by the States
               and Commonwealth need to be reconciled if this objective is to be achievable.
     3.    To maximise the economic efficiency of the ocean perch fishery.
     4.    To implement effective and efficient fisheries management on behalf of the
           Commonwealth.

          Strategies
          The above objectives will be achieved by:
 1.       setting a TAC for the Commonwealth managed portion of the fishery that:
                maintains catch per unit effort (CPUE) above its lowest annual average level from
                 1986 to 1994
              [Note: the TAC would currently only apply to the trawl sector of the fishery within the
              SEF, excluding the southern Remote Zone]
              (objectives 1 & 2)
 2.        managing all sectors of the ocean perch fishery in a complementary manner
            (objectives 1 & 4)
 3.        prioritising ocean perch research in relation to other SEF species:
             SETMAC has given a low research priority rating to this species
 4.        data collection
            (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing
                 practices
            (ii) monitor length distributions in commercial catches
            (iii)determining the number of species of ocean perch present in the commercial SEF catch
 5.        undertaking economic research on fishery to calculate GVP and monitoring market prices
           for ocean perch.

           Performance indicators
     1.    That the current annual CPUE for the fishery is above its lowest annual average level from
           1986 to 1994. (Strategy 1)
     2.    That all sectors of the fishery are managed in a complementary manner.
           (Strategy 2)
     3.    Data relevant to the annual assessment of ocean perch has been collected and analysed, and
           considered by SEFAG. (Strategies 1, 3, 4 & 5)
     4.    The actual trawl catch relative to the trawl TAC. (Strategy 1)

     2.    STOCK STRUCTURE AND LIFE HISTORY
           Ocean perches, of the Helicolenus species complex, inhabit southern waters of Australia
           and New Zealand. In Australia they are distributed from 29o S in NSW to 26o S in WA, at


          152                                                                          SEF Species Summary 1999
     depths between 50 and 750 m. It is not known how far west the distributions of the two
     quota species of ocean perch (inshore and offshore) extend to. Off NSW, they have depth
     distributions which possibly overlap at about 300 m. They can be distinguished by external
     colour and morphology, but have similar protein fingerprints.
     The inshore species reaches a maximum size of around 40 cm and the offshore species
     about 47 cm. Both species appear to be long-lived (around 40 years) and to have a low
     fecundity. They reach maturity at around 30 cm and probably spawn once a year in late
     winter to early spring. Length frequency distributions suggest females attain a larger size
     than males (Figs. 5.5.5-7).

3.   THE FISHERY
     Current situation
     The bulk of ocean perch landings consists of offshore species taken by trawlers. These
     catches are largely a by-catch whilst targeting other species; only 20% of catches appear to
     be targeted. Only small incidental by-catches are taken by the non-trawl sector and 1998
     SEF Commonwealth non-trawl landings totalled 5.3?? t.
     The 1998 SEF2 recorded landings of ocean perch were 363 t (351 t in Commonwealth
     waters and 12 t in State waters), which was 62% of the allocated TAC of 587 t. This total
     was 14% less than 1997 landings (423 t). The fishery is mainly in the Eastern A and B
     sectors of the SEF, from Sydney to Lakes Entrance.
     The initial agreed TAC (1992) for trawl catches was 300 t, but it was increased to 500 t
     from 1994 in anticipation of increased by-catches following the raising of the blue
     grenadier TAC to 10 000 t. Actual ocean perch TACs were 509 t in 1994, 574 t in 1995
     and 600 t in 1996 but only 59%, 55% and 59% of these TACs were landed, respectively.
     SMP/ISMP data indicate discard rates to be very high, particularly for the smaller inshore
     species, and actual catches (including discards) probably were near to, or exceeded, the
     TACs since 1992 (see below). The 1999 TAC is 500 t with an actual TAC of 592.9 t.
     The gross value of recorded landings of ocean perch by Commonwealth trawlers in 1998
     was estimated to be about $1.1 million, 16 per cent higher than in 1997. This increase was
     due to increased landings.
     Port meetings held in 1996 and 1997 highlighted the management difficulties caused by
     having two species under the one TAC. The two forms of ocean perches are generally well
     known in the trawl sector and are marketed under different names. The inshore 'coral cod'
     often fetches slightly lower market prices than the offshore 'ocean perch', although this is
     mainly due to the smaller size of the inshore form. Size-linked price differences mentioned
     by industry were significant, ranging from $1 to $4/kg, and lead to high discarding of small
     fish. SMP data confirm that discarding rates for the comparatively smaller ‗coral cod‘ are
     very high. In 1998, Ulladulla fishers noted that there had been a shift to using multi-
     purpose, high-rise nets which were not as effective at catching ocean perch as ‗scratch‘ nets
     with chain foot-lines. Wollongong fishers noted that more fish had been caught in 1997 as a
     bycatch of fishing wider for royal red prawns.

4.   PREVIOUS ASSESSMENTS
     This section needs to be summarised
     Assessments of ocean perches have been of poor quality due to lack of dedicated analysis
     of biological and fisheries data, and the problems with species/stock discrimination. No
     yield estimates are available. Initial TACs were based on historic catches only and later
     increased to cover the probable by-catch of ocean perch in blue grenadier and ling catches,
     when the TACs for these two species were raised. The status of each of the ocean perch
     resources (i.e. inshore and offshore species) is unclear, but there is some evidence that
     catch rates and mean length of fish have decreased in the Eastern Sectors since 1991.
     A detailed analysis of the size composition and catch rates of ocean perch was undertaken
     in 1997. Information available from the Ocean perch catches are subject to very high
     discarding rates, especially of the inshore species. Catches recorded in logbooks reflect


     Ocean Perch                                                                                     153
only retained catches, which is a relatively small proportion of fish actually caught.
Discarding is mostly market driven, with smaller fish of both species fetching low market
prices.
Between 1993 and 1995, onboard monitoring of trawl catches off NSW have shown that an
average of 40% of the offshore species catch and 85% of the inshore species catch (by
weight) were discarded (Liggins 1996). These corresponded to 70 and 93% by number. A
significant amount of discarding still occurred in 1996, with 83% by weight of the inshore
species and 18% of the offshore species being trashed off NSW. However, this represented
a significant reduction for the offshore species from 56% by weight in 1995.
The offshore species may reach lengths of 47cm and most fish greater than 25 cm are
retained. The inshore fish that are retained are usually between 20 and 30 cm.
This assessment incorporates data from the Kapala Report. This report summarises fishery-
independent replicate trawl surveys undertaken by this vessel on trawl grounds off Sydney,
Ulladulla and Eden in 1976/77, 1979/81 and 1996/97. The depths surveyed ranged from
220 to 605 m, which encompass the main distribution of the offshore ocean perch species
and part of the distribution of the inshore species.
Catch and effort
This species group has triggered the AFMA catch-rate performance criterion for three
consecutive years (1995-97). However, there was again no formal assessment undertaken
during 1998 because no resources were specifically allocated for this task. Available catch
and effort data and biological information from the ISMP were reviewed for this update,
together with information from the ―Kapala Report‖ (Andrew et al 1997).
Interpretation of catch rates is confounded by there being two species and the high discard
rate. The SMP/ISMP programs have recorded landings and discard rates for each species
separately. If it is assumed that SMP/ISMP data for Eastern Sectors A and B are
representative for all catches in this area over the period 1993-97, then the annual landings
recorded on the logbook database can be translated into the total annual catches of each
species (Table 1).
Table 1. Estimated total catch (t) of ocean perch by species for Eastern Sectors A and B
             1993          1994          1995         1996          1997          TOTAL         %*
logbook      227           212           175          201           212           1027
Inshore      151           161           377          200           153           1042          44.7
Offshore     275           308           278          204           225           1290          55.3
Total*       426           469           655          404           378           2332
* for estimated actual catches only


The estimated proportion by weight of the inshore species in the catch during 1993-97
ranged from 34% (1994) to 58% (1995), with a mean of 45%. Annual landings from
Eastern Sectors A and B comprised 88% (93), 82% (94), 73% (95), 76% (96), 73% (97)
and 84% (98) of those for the whole SEF logbook database. Thus, the estimated actual
catch exceeded the allocated TAC in 1993 to 1995, but was under the TAC in 1996, 1997
and 1998.
Virtually all the ocean perch catch is taken between depths of 100-650 m. The precise
depth distributions of each species are unknown, but there is little doubt that considerable
overlap occurs, probably around the shelf break region. Thus, logbook catches cannot be
separated into each species by using depth criteria. However, both species are largely taken
as a bycatch of targeting other species, or as a targeted component of ‗scratch‘ (i.e. mixed
species) fishing. The use of total estimated catch together with total effort (bottom time)
within the 100-650 m depth strata may be a better indicator of abundance than that obtained
by using shots containing landed catch only. These two CPUE analyses are compared in


154                                                                        SEF Species Summary 1999
Table 2. Little can be deduced from these two unstandardised analyses except that the ‗total
catch-effort‘ CPUE values were lower than the ‗1 kg‘ values, indicating that a significant
proportion of shots within the known depth range for these species did not contain
marketable ocean perch. The increased difference between the two rates in 1996 and 1997
indicates that the proportion of these shots also increased. The ‗1 kg‘ values suggest that
high discarding probably masked an improvement in catch rates in 1995 and reduced
discarding of the offshore species in 1996 and 1997 probably maintained catch rates at
around the 1995 level.
Table 2. Mean annual unstandardised catch rates (kg/hr) for ocean perch 1993 to 1997.
                   1993             1994              1995               1996              1997
A&B effort *       29178            33510             39411              46653             49082
A&B catch (t)      426              469               655                404               378
A&B CPUE           14.6             14.0              16.6               8.7               7.7
1kg CPUE**         19.0             19.7              14.5               13.4              13.4
* All effort (hrs) between 100 and 650 m depth only. ** For all shots containing >1kg of ocean perch.


Whereas both analyses suggest a decline in abundance of ocean perch over the period
1993-97, much more detailed analysis of catch/effort data is needed before any conclusions
can be made. More details of possible changes in fishing practices are required. During the
1998 port visits, industry noted that the shift to using high-rise nets, which are not as
effective at catching ocean perch as traditional ‗scratch‘ nets, may have depressed catch
rates. No concerns over the status of the ocean perch stocks were expressed by industry at
any of the 1997/98 port meetings.
Kapala data: The catch rates for ocean perch in depths of 330 to 495 m were pooled.
These depth strata are certainly representative for ocean perch. In Eastern Sector A, almost
60% of the SEF1 catch for 1986-97 was taken from this depth range. Kapala catch rates
showed a significant decline over the study period off Sydney and Ulladulla and a lesser
decline off Eden. However, in 1976/77, the areas fished were virtually ‗virgin‘ grounds, as
commercial fishing in these depths had only just started. The decline between 1976/77 and
1979/81 suggests that the initial years of the fishery had a significant impact on ocean perch
abundance, probably by harvesting the older, larger fish. Length frequency data for
1976/77 peak at around 35 cm LCF in all 3 areas. Such a reduction is to be expected in the
early years of a fishery. From 1979/81 to 1996/97, the data suggest that abundance has
declined further off Sydney and Ulladulla, but has remained more or less the same off
Eden.
The 1996/97 data strongly suggest that current ocean perch abundance increases from north
to south between Sydney and Gabo Island.
Size composition
Data summaries from Liggins (1997), the 1997 ISMP and the Kapala Report are used.
Inshore species: 1993 to 1996 catches from Ulladulla have shown a mode of around 18 cm
TL. In 1997, only discarded fish were measured off Ulladulla, but the mode remained the
same. Eden catches over 1993-96 contained a greater proportion of fish between 16 and 22
cm, but the mode was essentially similar to that of Ulladulla catches. 1997 Eden catches
were similar. In both ports, very few fish >25 cm were caught.
Offshore species: This species has a greater size range than the inshore species. Some size
variation was evident in Ulladulla catches over the period 1993 to 1996. but the bulk of the
retained catch remained between 25 and 40 cm. In 1997, there was a pronounced reduction
in fish >25 cm. The reasons for this marked change are unclear. The fact that only 5 shots
were sampled for retained fish may have skewed results. The size composition of Eden fish
remained essentially similar over 1993 to 1995 but contained a greater proportion of fish
>25 cm in 1996 and 1997.


Ocean Perch                                                                                             155
     Kapala data: As expected, comparison between aggregated 1976/77 length frequencies
     and those for 1996/97 show a marked reduction in the proportion of fish >30 cm LCF in the
     latter samples in all 3 areas. This difference became less pronounced with increasing depth.
     and no change was discernible in the 550-605 m depth stratum off Ulladulla and Eden. This
     was probably because recorded SEF1 fishing effort (and, hence, fishing mortality) in
     Eastern Sector A waters >550 m depth is very low compared with that in the 220-550 m
     depth range. Sexed 1996/97 length frequencies (Figs 5.5.5-7) showed females to dominate
     fish >35 cm, suggesting that females attain a larger size than males.
     Uncertainties in assessment
     Ocean perch have never been subject to detailed assessment and no yield estimates are
     available. This and previous assessments are heavily reliant upon logbook and SMP/ISMP
     data. This assessment is a first attempt to examine catch rates for the actual total catch (i.e.
     including discards) of both species, but much more detailed spatial/temporal analysis and
     details of fishing practice (e.g scratch versus high-lift nets) are needed.
     The Kapala Report has been challenged by industry, but the results are very consistent for
     all three sampling areas. Industry‘s claim that the results are essentially ―snapshots‖
     overlooks the fact that all locations were sampled on three or four occasions in during the
     sampling periods. Whereas, inter-annual fluctuations in abundance or catchability are
     known to occur for some quota species off NSW, this does not appear to be the case for
     ocean perch. From 1986 to 1997, SEF1 data show annual Eastern Sector A landings to be
     comparatively consistent, typically being between 50-60% of the total SEF landings.

5.   1999 UPDATE
     There was no formal assessment of ocean perch undertaken during 1999. However, 1998
     logbook and ISMP data were incorporated into this summary.
     Catch and effort
     The 1998 SEF2 landed weight of ocean perch was 363 t (351 t in Commonwealth waters
     and 12 t in State waters), which was 62% of the allocated TAC of 587 t. It represents a
     14% decrease compared to 1997 (423 t). The 1999 TAC remained at 500 t, with the
     allocated TAC being 593 t. Similar to other years, 1998 landings in Eastern A were double
     those in Eastern B, with comparatively low landings being recorded in the other zones.
     1998 landings from Victorian and Tasmanian endorsed vessels were 2.5 t and 8.9 t,
     respectively, and landings on the SEF non-trawl database totalled 5.3 t.
     Mean unstandardised catch rates of ocean perch were exactly the same in 1998 as in the
     previous two years (13.4 kg/hr) – makes me wonder if there is a problem with the data
     retrieval/analysis???? Nevertheless….. This is the fourth consecutive year in which the
     catch rates have triggered AFMA‘s catch rate performance criteria.
     Size composition
     The size composition of the retained and discarded catch is similar to those of previous
     years. There was no clear delineation of the size of fish that were retained or discarded but
     all fish below 20 cm were usually discarded while fish between 20 and 30 cm may either be
     retained or discarded. The mode of the retained catch of the offshore species was around
     30 cm.
     Discard rates
     Based on the ISMP data, the discarded weight of ocean perch across the SEF in 1998 was
     around 320 t (196±32 t for the inshore species and 123±20 t for the offshore species).
     Combined with the SEF2 landings of 363 t, the total catch of ocean perch (including
     discards) during 1998 was 683 t, which is 16% over the allocated TAC.
     Overall, discarding rates for the inshore species (58% by weight) were more than double
     those of the offshore species (27%), but there were noticeable differences in the rates of
     discarding at different regions along the east coast. Discarding rates were generally lower
     in the ports north of Eden (35 – 50% for the inshore species and 14% for the offshore
     species) than around the Eden / Lakes Entrance regions (90% inshore and 40% offshore).




     156                                                                          SEF Species Summary 1999
     Port meetings
     The 1999 port meetings were focussed in ports to the west of Bass Strait and there was no
     discussion about ocean perch. Previous port meetings have highlighted the management
     difficulties caused by having two species under the one TAC. The two forms of ocean
     perches are generally well known in the trawl sector and are marketed under different
     names. The inshore 'coral cod' often fetches slightly lower market prices than the offshore
     'ocean perch', although this is mainly due to the smaller size of the inshore form. Size-
     linked price differences mentioned by industry were significant, ranging from $1 to $4/kg,
     and lead to high discarding of small fish. SMP data confirm that discarding rates for the
     comparatively smaller ‗coral cod‘ are very high. In 1998, Ulladulla fishers noted that there
     had been a shift to using multi-purpose, high-rise nets which were not as effective at
     catching ocean perch as ‗scratch‘ nets with chain foot-lines. Wollongong fishers noted that
     more fish had been caught in 1997 as a bycatch of fishing wider for royal red prawns.
     Prices
     In 1998, the gross value of recorded landings of ocean perch was estimated to be about
     $1.00 million. Prices averaged $2.73/kg on the Sydney Fish Market during 1998, slightly
     higher than those in Melbourne ($1.59/kg).

6.   IMPLICATIONS FOR MANAGEMENT
     Confusion about the taxa to be included in the 'ocean perch' quota has existed since the
     introduction of ITQs in the SEF. This confusion has caused difficulties for compliance,
     although this has lessened since the publication of the new CSIRO guide to SEF quota
     species. For biological conservation reasons, it is not desirable to have separate species
     under a common TAC. The situation is further complicated by very high, but differential,
     discarding rates for each species, which also vary between ports. Both industry and
     scientists have expressed ongoing concern that two distinct species are included under a
     common TAC. Because market prices are largely size dependent, it is debatable if a
     separate TAC for each species would reduce the incidence of discarding.
     The TAC for ocean perches was increased by 150% between 1992 and 1994, well above
     historical catch levels. This was done to accommodate the increased by-catch of these
     species that would theoretically result from the large increase in the blue grenadier TAC
     and rises in the ling TAC. Considering that ocean perches are caught mostly at sizes below
     the suspected size at maturity and that they appear to be long-lived species with a low
     brood size, the sustainability of the stocks under the current TAC level is uncertain. There
     is some evidence of a decrease in the size of the offshore form in commercial catches.
     Also, catches from north of the SEF could be from the same stocks, but are not currently
     restricted by the TAC.
     Because most of the ocean perch catch is discarded, particularly that of H. percoides, the
     actual catch probably exceeds, or is near, the TAC. The status of ocean perch stocks is
     uncertain but the high level of discarding remains of concern.
     Because ocean perch are largely taken as a bycatch of targeting other species, or as a
     targeted component of ‗scratch‘ (i.e. mixed species) fishing, the significant rise in total SEF
     fishing effort on the upper slope/shelf-break/shelf over the past few years must be having a
     greater impact on the stocks. If this rise in effort continues, the risks to catch sustainability
     also increase.
     Whereas the Kapala surveys indicate a significant decline in ocean perch abundance
     occurred between 1976/77 and 1979/81, such a reduction is to be expected in the early
     years of a virgin fishery. These surveys also suggest that a (lesser) decline in abundance has
     occurred between 1979/81 and 1996/97. However, this decline could have occurred during
     the early years of this period, with abundance since becoming stabilised. The key issue of
     whether abundance is continuing to decline as a result of excessive harvesting remains
     unresolved.




     Ocean Perch                                                                                         157
7.   RESEARCH NEEDS
     Ocean perches have been given a low priority for future research. Apart from a recent
     genetic study on stock discrimination which supported the existence of two species, there is
     no specific research project being undertaken on the biology and fishery of ocean perches,
     and no proper assessment can be made.
     Whilst differences between the two species off the NSW coast are well recognised by
     industry, further research may be required to identify morphological criteria which
     distinguish the forms at more southern latitudes.
     Given the high level of discarding of ocean perches, it is important to continue to collect
     information on the size and species composition of discarded/graded catches. It is
     important to consider discarding levels and possible changes in fishing practice if stock
     status is to be assessed by analysing trends in CPUE. The motives governing fishing and
     discarding practices, such as responses to market dynamics and quota holdings must also be
     understood.
     Ocean perch are a key species in proposed gear selectivity studies for the SEF.
     Analysis of species composition associated with ocean perch trawl catches is needed to
     understand how the temporal and spatial trends in fishing for other targeted species
     influence catches of ocean perches.
     Collection of biological data (size composition, age, fecundity) should be made for each
     species separately. Age/growth studies are needed to verify possible differences between
     sexes.
     Although recorded catches by the non-trawl sector have been small so far, the historical
     development of the fisheries involved, their current catch dynamics and potential for further
     development (export of live fish, for example) should be examined in provision for the
     future management of this sector.




     158                                                                       SEF Species Summary 1999
                        600                                                                                      actual TAC

Total catch (tonnes)                                                                                         approved TAC
                        400




                        200




                                              0
                                                       1992    1993     1994     1995     1996    1997    1998
                                                                                 Year



   Figure I Total annual verified catches of ocean perch calculated from the quota
            monitoring system (SEF2), and actual and approved total allowable catches
            (TAC)




                                              25


                                              20
                       av.catch rate(kg/hr)




                                              15


                                              10


                                                  5


                                                  0
                                                      85 86   87 88   89 90    91 92 93   94 95   96 97   98 99


   Figure II Average annual unstandardised catch rates of ocean perch




   Ocean Perch                                                                                                                159
              Appendix A.1 : Recorded Commercial Catch History within the SEF area (tonnes) – Ocean Perch


                                        Commonwealth Records                                             State Records
                      TAC                        Retained Catch                                         Retained Catch




                                                                                                                                                            discarded catch3
                                                                                                                                         catch within the
                                         Commonwealth




                                                                                                                                         Estimated total
                                                        SEF 2 State




                                                                                                                                                               Estimated
                                                                                                                                            SEF area2
                            Allocated




                                                          Waters
             Agreed




                                                                                       Total1
                                                                      SEF 1


                                                                              Other
                                            SEF2




                                                                                                 NSW
 Year




                                                                                                                       Tas


                                                                                                                                  S.A.
                                                                                                           Vic
1977                                                                                              200                                             200
1978                                                                                              250                                             250
1979                                                                                              200                                             200
1980                                                                                              200                                             200
1981                                                                                              250                                             250
1982                                                                                              275                                             275
                                                         SEF not Established
1983                                                                                              400                                             400
1984                                                                            177   177          52                                             229
1985                                                                            261   261           2                                             263
1986                                                                    264     223   223          54                                             277
1987                                                                    199     212   212          16             7                               235
1988                                                                    187     237   237          32            10                               279
1989                                                                    207     222   222          30            17                               269
1990                                                                    181           181          13             7           3                   204
1991                                                                    224           224          14             9          <1                   247
1992        200         300                    196         6            170           202          13             3           1                   219
1993        300         302                    302        30            248           332          17             8           9                   366
1994        500         509                    276        27            257           303          24             8           6                   341
1995        500         574                    275        40            240           315          46             8           2                   371
1996        500         601                    319        37            263           356          36             8          11                   411
1997        500         603                    393        30            290           423           ?             ?           9
1998        500         587                    351        12            271           363           ?             ?           2

Commonwealth records:                                                         State records:
         1984 - 1989 verified catch history                                   1977 - 83 NSW landings (FMA fin/yr)
         1990 - 1991 SEF Logbook                                              1984 - 96 NSW FRI
         1992 - 1998 AFMA quota monitoring unit                               1990 - 98 DPI Tasmania




1.      Total of the shaded cells                                                                Abbreviations:
2.      Estimated by totaling Commonwealth and State records.                                         N/A = Not Applicable
3       Estimated from the SMP                                                                        ND = No Data Available
                                                                                                       ? = Available data not received




              160                                                                                                     SEF Species Summary 1999
Ocean Perch   161
        ORANGE ROUGHY


        1. AFMA'S MANAGEMENT OBJECTIVES, STRATEGY AND PERFORMANCE CRITERIA

        Objectives
        On-going
     1. To ensure that the orange roughy resource is utilised in a manner consistent with the principles of
        ecologically sustainable development.

        Immediate Objective
         To maintain the long term productivity of each stock in the orange roughy fishery: the current
          assumption is the separate eastern, southern, and western stocks exist.

             To maximise the economic efficiency of the orange roughy fishery

             To implement effective and efficient fisheries management on behalf of the Commonwealth.


        Strategies
        The above objectives will be achieved by:
 1.     maintaining the spawning biomass of each orange roughy stock above 30% of the spawning biomass at the
        onset of significant commercial fishing (1988)3:

 2.     where there is a greater than 50% probability that a stock is below 30% of the 1988 spawning biomass, then
        the TAC for the stock will be set in future such that the biomass reaches 30% B0 by 20044

        There needs to be consideration by SEFAG of the following strategy options:

        (i)    where there is greater than 50% probability that the stock is below 20% of the 1988 spawning
               biomass, then the TAC will be zero and remain at zero until there is a greater than 50% probability
               that the spawning biomass exceeds 20%Bo

        (ii) where the stock is at such a low level of Bo that the recovery to 30%Bo cannot be attained by 2004
             that years of zero TAC may be necessary for stock recovery

        (objective 1)

3.      prioritising orange roughy research in relation to other SEF species:
            SETMAC has given a high priority rating to this species
        (objectives 1,2 & 3)

4.      data collection
         (i)     refine estimates of recent and current catches (recorded and non-recorded) from each orange
                 roughy zone in the fishery and areas no subject to quota
         (ii)    refine fisheries models of the eastern and southern zones to improve estimates of original and
                 current biomass
         (iii) support initiatives for determining stock size in the western zone

               undertaking risk analyses for a variety of management strategies

        3
            note that for eastern/southern stock(s) if there is to be less than 10% chance of the stock being below 30%B 0, then the current
                    spawning biomass should be kept at around 38%B o


        4
            note that this is the basis of the current TAC strategy for the eastern/southern stock(s) which is currently estimated to be at
                    around 25% Bo



        162                                                                                            SEF Species Summary 1999
          undertake stock delineation research to determine whether the fishery comprises one or more stocks

          (objective 1)

     5.   undertake economic research on the fishery to calculate GVP and monitor market prices for orange
          roughy

          (objective 2)


     Performance Indicators
     1. That TACs are set such that the eastern/southern stock(s) are rebuilding toward 30% B o

          (strategy 1)

     2. Data relevant to the annual assessment of each orange roughy stock has been collected and analysed
     and considered by SEFAG

          (strategies 3 & 4)


2.   STOCK STRUCTURE AND LIFE HISTORY
     Orange roughy occur virtually throughout the SEF mid-slope (i.e. 700 - 1 200 m depth) waters, however
     catches from the SW sector and the Remote Zone dominate. Genetic (allozyme) data indicate differences
     between the Southern Zone, the South Tasman Rise, Lord Howe Rise and New Zealand fisheries (Tilzey,
     pers. comm.). Otolith microchemistry data indicate that South Tasman Rise fish and Cascade Plateau fish
     are distinct from one another and from Eastern and Southern zone fish; New Zealand and Australian
     mainland fish differ from one another, but there is little internal structure (Thresher, unpublished data).
     Biological information indicates a difference between stocks off NSW and eastern Tasmania. Otolith shape
     data indicate that spawning eastern zone roughy and southern zone non-spawning roughy may comprise a
     common stock, which is distinct from an eastern non-spawning and southern winter-caught ‗stock‖
     (Robertson et al. in prep.). Fisher‘s observations suggest that there is little interchange of pelagic roughy
     schools between Pedra Branca and Maatsuyker, while processors suggest that fish from the two areas are
     morphologically distinct. Stock structure on the west coast of Tasmania and in the Great Australian Bight is
     ill defined.
     Orange roughy is a long lived species with a maximum age of over 100 years and age at maturity of 20 to
     40 years. Orange roughy have low fecundity. Spawning occurs in winter and in the SW Sector only one
     major spawning site is known  St. Helens, located off eastern Tasmania. Fisheries on the Cascade Plateau
     and South Tasman Rise target spawning aggregations. Orange roughy also form non-spawning
     aggregations.

     Orange roughy feed on benthopelagic and mesopelagic organisms, notably prawns, fish and squid. A recent
     review found no evidence of sperm whale predation on orange roughy.


3.   THE FISHERY

     3.1 Brief History
     Commercial fishing for orange roughy commenced in 1982. The first substantial catches of roughy were
     taken from a non-spawning aggregation off Sandy Cape, western Tasmania, in 1986. Between 1986 and
     1988 landings ranged between 4 600 and 7 200 t per annum. Landings increased to 26 000 t in 1989 and 41
     000 t in 1990 with the discoveries of non-spawning aggregations off southern Tasmania and a major
     spawning aggregation off eastern Tasmania. Further increases in catch were then prevented by the creation
     of the Eastern and Southern Management Zones and associated TACs.
     Developmental fishing in the Remote Zone yielded 2 000 t of roughy in 1989/90 primarily from foreign
     vessels. Australian vessels started cosnsitently fishing the Cascade Plateau in 1996. In 1997 the SETMAC 1
     000 t trigger limit was caught by late April and the fishery closed. A monitoring program was set up in

     Orange Roughy                                                                                            163
     1998, funded from a voluntary industry levy, and TAC set at 1600 tonnes divided into 400 tonnes per
     quarter – 1560 t were caught.
     Fishing on the South Tasman Rise (which straddles the Australian EEZ and International waters) was
     sporadic until 1997 when it developed strongly (Clark 1999). Total Australian catch in 1997 (January 1 to
     December 17) was 1 668 t, while the New Zealand catch was 430 t for a total of 2 099 t (Clark reports
     combined catch of 1 865 t). From January 1 to March 1998 the Australian catch was 2 052 t. An annual
     TAC of 1 669 t for Australian operators and 431 t for New Zealand operators was introduced for the year
     starting March 1998. Total Australian catch for the year was reported as 3 054; combined catch was 3 508 t
     (Clark 1999).
     Catches of orange roughy from 326 to 3 783 t have been taken in the Great Australian Bight since 1987, but
     catches since 1994 have been less than 400 t. Catches off Western Australia have been taken since 1994 but
     have not exceeded 250 t.
     Reported catches of orange roughy on the Lord Howe Rise and NW Challenger Plateau have varied
     between 400 and 5 350 t since 1988. Long-term sustainable catches for the two areas combined (assuming a
     single stock) are on the order of 400-500 t (Clark and Tilzey 1996).

     3.2 Current Situation
     TACs (with full allocation) and catches reported in the SEF logbooks are given below. The 10 000 t
     Southern Management Zone allocation in 1993 was part of an adaptive management experiment.
     Table 1 Orange roughy TACs and reported catches.

        Year                               Actual TAC (t)                               Reported catch (t)
                    Eastern         Southern      Western           Eastern         Southern     Western

         1992          8,128            8,500           1,626          7,423            8,007          1,154
         1993          2,039           10,535           1,676          1,955            7,639          1,032
         1994          1,571            7,735           2,221          1,682            4,353            927
         1995          1,920            5,424           1,912          1,959            2,159          1,055
         1996          1,940            4,208           1,804          1,998              802          1,320
         1997          1,972            1,813           1,717          2,063              454            352
         1998          1,909            1,000           1,933          1,968              251            361


     Unconfirmed reports suggest that actual catches in 1992 were double those reported. There is one report
     that 1993 landings into Hobart were double reported landings (Tasmania Police Marine Division), but this
     is not generally accepted. Reports and analyses indicate a proportion of the 1993 Eastern Management
     Zone catches were reported to come from the Southern Management Zone.
     Increased difficulties in catching roughy in the Southern Management Zone, reduced quotas and high costs
     of leasing quota have led to several operators not finding it profitable to fish this zone. The 1997 Southern
     Zone TAC was reduced disproportionately (compared to the Eastern Zone TAC) to reduce combined
     catches from the Eastern and Southern Zone.
     Vessels reporting catches of orange roughy peaked at 66 in 1990 with 8,243 shots. This declined to about
     4,000 shots per annum by 1995 with 30% of vessels accounting for 60% of shots. About 35 vessels have
     reported orange roughy catches in the last 5 years.


4.   PREVIOUS ASSESSMENTS
     Following a favourable international review of the Eastern and Southern zones assessments in 1994, the
     1994 and 1995 TAC Sub-committees and SETMAC endorsed a TAC scenario that should have ensured
     that orange roughy in Eastern and Southern zones were rebuilt to equal or exceed AFMA‘s performance
     criterion of 30 per cent of pre-fishery biomass by 2004. This TAC scenario maintained the Eastern Zone
     TAC at 2000t but reduced the Southern Zone TAC to 2000 t in 1997 and to 1500 t after 1997. Refinement
     of earlier acoustic results and incorporation of 1995 catch rate data (for the Southern Zone only) in the
     1996 assessment gave a more pessimistic outlook and a risk averse strategy (one that would meet AFMA‘s
     performance criterion under either of two likely natural mortality schedules and giving slightly greater
     weight to the combined Eastern and Southern zones assessment as recommended by the 1994 reviewers)

     164                                                                         SEF Species Summary 1999
     was defined as one where catches in the Southern Zone were reduced to 1200 t from 1997 to 2004. Largely
     at the prompting of industry who wished to rest some of the southern hills, the 1996 TAC Sub-committee
     further reduced the 1997 Southern Zone TAC to 1000 t. With carryover, 1813 t were allocated.
     The 1997 assessment was more pessimistic than that of 1996. Following analyses of otolith shape, it now
     appears probable that a signficant proportion of fish in the Eastern and Southern zones comprise a common
     migratory stock. Therefore more weight was given to a combined zones assessment in 1997. Results of the
     1997 assessment (using the same data as the 1996 assessment) for the same risk averse strategy used in the
     1996 assessment, required that catches in the combined Eastern and Southern zones be reduced to 2000 t
     from 1998. This more pessimstic result was due to: increased emphasis on a combined zones assessment
     and an increase in the 1990 acoustic biomass estimate caused by analysing these data in the same manner as
     subsequent years (same deadzone height). and, including a change in species composition at St Helens due
     to the decline in orange roughy biomass, while the biomass of other species (e.g. whiptails) is assumed to
     remain constant
     New data from the 1996 acoustic biomass survey at St Helens were available for the 1997 assessment,
     however, there was a timing mismatch between the time of the survey and the time of maximum
     commercial catches at St Helens. When the 1996 survey (increased by 30% to perhaps account for the
     timing mismatch) were included, the same risk averse strategy required that catches in the combined zones
     be reduced to 1000 t from 1998. The main reasons for this more pessimistic assessment are the 1996
     biomass estimate, and including a change in species composition at St Helens due to the decline in orange
     roughy biomass, while the biomass of other species (e.g. whiptails) is assumed to remain constant (changed
     species composition does not depend on data from the 1996 survey).
     Industry presented their independent view on the 1997 assessment, emphasizing that variability in timing
     and distribution of roughy in the St Helens area makes interpretation of biomass estimates at St Helens
     difficult, disputing the conclusion that the proportion of whiptails at St Helens has increased, questioning
     the selection of the lower rate of natural mortality (and ageing of roughy in general), and concluding that
     they cannot support an assessment that differs so significantly from that reviewed in 1994 despite the lack
     of new credible survey data.
     TACs for 1998 were set at 2 000 t for the Eastern zone, 1 000 t for the Southern zone. This equates to 3
     000 t for the combined zones, although in recent years less than half the Southern Zone Tac has been
     taken..
     An initial attempt to provide an assessment for the Western Zone in 1997 was unsuccessful because of
     difficulties in interpreting the catch and effort data. These are the only data available on relative abundance
     between years. The 1998 TAC wase set at 1 500 t.
     The 1000 t trigger for the Cascade Plateau was caught by April, 1997 and AFMA closed the area to fishing.
     A research and strategic fishing proposal was developed for the Cascade Plateau by industry, scientists and
     managers. This proposal was not effected for the 1997 fishing season. The 1998 TAC was set at 1 600 t
     (400 t per quarter) and a monitoring program set in place funded by a voluntary industry levy.

5.   1999 ASSESSMENT
     Assessment efforts in 1999 were concentrated on analysis of early age composition data, updating
     the assessment model to a full Bayesian model, and planning an acoustic biomass survey at the St
     Helens hill for the 1999 spawning season. A 5-year draft strategic assessment plan has been
     drafted for the major Australian roughy fisheries and is being circulated amongst industry for
     comment.

     5.1 Industry Information
     5.1.1 St Helens
     Industry reported a large number of marks on St. Helens in 1997 and 1998 (better marks than seen for the
     last four years) and fishing practices were modified to take smaller catches at the edges of larger marks.
     The majority of fish were taken off St. Helens in 1997 and 1998, with no repeat of the 1996 pattern of large
     numbers being taken from Patricks Head.
     5.1.2 Southern Zone
     Fishing effort remains low in the Southern Zone compared with earlier years. Since 1994, tows have been
     targeted on known trawl grounds, rather than distinct marks, as the latter have disappeared.


     Orange Roughy                                                                                              165
5.1.3 Western Zone
Since 1996, when effort in the Western Zone increased and some good catches were made (especially by
operators experienced in targeting small aggregations similar to those fished in the Southern Zone and
especially in July and August on full moon), effort has declined.
5.1.4 Cascade Plateau
Several hundred tons were caught at the start of the second opening on April 1, then the fishery went quiet
and most vessels diverted to the South Tasman Rise. One vessel that remained on the Cascade Plateau
reported that fishing remained quiet.
5.1.5 South Tasman Rise
The season started on April 1 and Australian vessels moved to the South Tasman Rise from the Cascade
Plateau. Catches were patchy earlier on in the season with many vessels dodging the weather. One location,
where a school forms sporadically, was fished consistently resulting in mostly zero shots but the occasional
shot of 50-100 t. The proportion of non-zero shots increased through April and the Australian quota was
filled (total catch 1723 t).
New Zealand vessels fishing the South Tasman Rise greatly exceeded their quota. The latest catch estimate
is 1620 t. Although the New Zealand minister declared the fishery closed within a few days of Australia
declaring it closed, several vessels continued fishing until June 2, when enforceable regulations were put in
place.

5.2 Assessment Process
Following the contentious 1997 assessment, assessment funds have been diverted to reanalysis and
reinterpretation of the acoustic biomass estimates (and other biological data), involving industry members
and scientists. Reanalysis of acoustic data included examination of a ―schools approach‖ for interpretation
of acoustic biomass data to reduce the need for species composition data. An additional meeting with
fishers with long-term experience of the St Helens fishery was scheduled to assist interpretation of the
acoustic data. This meeting did not occur due to unavailability of key persons.
Examination of the fit of the assessment model to age composition data collected at St Helens in 1992 and
1995 showed major inconsistencies between assumed and sampled age compositions. In addition, a major
shift in age composition shown in the sampled ages did not occur in the modelled ages. This suggests that
the underlying assessment model does not accurately represent the underlying population dynamics.
Analysis of a 1987 age composition and analysis of the 1999 age composition has been supported by
SETMAC to resolve this issue.
The 1999 survey of the St Helens spawning aggregation is the first comprehensive acoustic survey since
1992. It will also provide the further age composition sample, to determine the consistency of earlier age
composition data, will quantify fishers‘ observations of increased abundance of orange roughy in the last
two years (1997 and 1998). More detailed biological sampling than in previous surveys has been planned to
resolve some questions on the aggregatin dynamics of the roughy.
We t determined to defer an assessment until 2000, by which time the new data and additional age
composition samples will be available. In the meantime the assessment model has been updated to a full
Bayesian model that is more flexible and will facilitate analysis of fits to other data including age
composition data, and to estimating additional parameters.
The 1999 Assessment Report provides an update of biological and catch data only.

5.3 Results
Stock structure for the Southern and Eastern zones remains unclear. However CAF (Robertson et al. in
prep.) research on otolith shape indicates that spawning eastern zone roughy and southern zone non-
spawning roughy may comprise a common stock, which is distinct from an eastern non-spawning and
southern winter-caught ‗stock‖.
Results from analysis of otolith microchemistry are not clear cut, but suggest that Lord Howe Rise is a
separate stock and that St Helens and Cascade Plateau are different from Maatsuyker (Ron Thresher
CSIRO, pers.comm). Analysis is continuing.
5.3.1   Analysis of Catch Data
These analyses do not account for changes in fishers‘ behaviour as detailed by industry members. Results
should be interpreted in that light.


166                                                                        SEF Species Summary 1999
     Estimates of the mean catch per shot by area and year from the models are summarised in the Table 2 and
     Figure II. Estimates of the mean catch per shot by year in Maatsuyker and Pedra Branca include either
     quarters 1, 2 and 4 (September to May) or quarter 3 (June to August). The estimates for the western areas
     exclude winter (quarter 3), and the estimates for the eastern areas are given for winter only.
     The addition of the 1998 data does not change the trends observed in the analysis last year.

     Table 2. Summary of catch per shot estimates.

     Area           Season                               Year                                            98/89
                                     89    90     91     92 93         94     95     96     97     98     %

     Maatsuyker     Non-winter     2.21   1.54   0.50   0.42   0.26   0.25   0.20   0.14   0.12   0.04       2
     Maatsuyker     Winter         3.72   1.59   0.69   2.02   0.52   0.33   0.11   0.19   0.12   0.03       1
     Pedra Branca   Non-winter     2.26   1.23   0.57   0.74   0.36   0.14   0.11   0.12   0.12   0.07       3
     Pedra Branca   Winter         3.27   1.33   1.27   1.85   0.78   0.22   0.08   0.09   0.10   0.08       2
     East           Annual         2.69   3.94   0.89   1.54   0.44   1.12   0.84   0.53   0.81   0.53      20
     West           Annual         0.10   0.23   0.14   0.12   0.16   0.20   0.13   0.09   0.06   0.05      54
     King Island    Annual         0.41   0.29   0.28   0.19   0.16   0.12   0.07   0.06   0.07   0.06      15
     West Tas       Annual         0.15   0.25   0.20   0.58   0.38   0.21   0.14   0.07   0.05   0.06      39
     SW Tas         Annual         0.24   0.29   0.61   1.05   0.50   0.40   0.27   0.19   0.16   0.11      47
     St Helens      Annual         2.88   4.70   0.52   1.53   0.34   1.18   0.70   0.17   0.55   0.50      17
     Paddys Head    Annual         0.40   0.47   0.63   1.52   0.32   0.02   0.76   0.91   1.51   0.40     101

     Data for the southern and eastern areas (except for Paddys head) indicate a substantial decline in catch per
     shot, especially those for the Southern Zone. Catch per shot at Paddys Head is very variable between years.
     The trends for Maatsuyker and Pedrabranca confirm an industry observer's opinion that catches were high
     in 1989 and 1990, but experienced a major decline in 1991 and 1992. Catch per shot at Maatsuyker
     declined again in 1993, Pedrabranca declined again in 1994 (this is about the same time that fishers could
     no longer see schools to target and towed set shots). Catch per shot is now less than one-tenth its value at
     the start of the fishery. Catch per shot at St. Helens has been more variable. An overall decline is apparent
     with present catch per shot less than one fifth that at the start of the fishery. Catch per shot increased in
     1997 and 1998 relative to 1996, matching operators reports that marks were better than had been seen in
     previous years.
     Interpretation of these data is complicated by changes in fishing practices which have led to decreased
     targeting in southern zone and skimming schools at St Helens to reduce size of individual catches.
     Catch per shot in the western zone areas has a more complicated pattern - generally an initial increase
     followed by a decrease after 91 and 92. These data suggest that there may have been a change in fishing
     behaviour at this time. Increased targeting of deepwater sharks involving long night-time shots in depths
     where roughy would be caught incidentally is one recent trend that would reduce overall catch per shot for
     roughy.
     5.4 Strategic Research Plan
     A strategic research plan is being developed for Australia‘s major roughy fisheries and has been circulated
     to roughy operators for comment.
     AFMA is addressing general questions of funding fishery assessments raised by this research plan with
     SETMAC. This may have implications for other SEF fisheries.

6.   MANAGEMENT ISSUES
     No new management implications were discussed. We determined that it was appropriate to defer
     discussing new management applications until next year‘s (2000) assessment, which will incorporate new
     age composition data (1987 and 1999) and a new biomass estimate (1999) in an updated assessment model.




     Orange Roughy                                                                                               167
7.   RESEARCH NEEDS IN ORDER OF PRIORITY

     Previously identified research needs --- otolith microchemistry analysis of stock structure; otolith
     morphometrics to distinguish stock structure; analysis of deepsea corals to estimate oceanographic
     variability; reanalysis of St Helens acoustic biomass estimates; reading of otoliths taken collected in 1987,
     have or are being addressed.
     The assessment model has been updated as previously identified. Further updating is required to
     incorporate additional data (eg. age frequency) and assumptions (eg. changing natural
     selectivity/availability, or stock mixing). An acoustic biomass estimate at St Helens is planned for the 1999
     winter season.
     Remaining high priority research needs in order of importance are:
     Key biological information is required from the Cascade Plateau and South Tasman Rise to determine
     ongoing scientific advice for these fisheries since catches have increased rapidly. Information should
     include description of any aggregative behaviour, especially during spawning that would determine the
     feasibility of a fishery-independent biomass survey.
     A review of available stock structure information is required. There are now considerable data available
     and stock structure has major implications on the assessment process and management advice.
     A review of ageing, age validation and natural mortality estimation is required. Recent data casts doubt on
     previous validation work, and two researchers claim that roughy are either much younger or much older
     than currently believed.
     Further assessment of undocumented acoustic data at St Helens is required to increase understanding on
     aggregation dynamics and implications for biomass estimation.
     Development of a framework to determine the value of increased data precision in developing and
     established orange roughy fisheries is required, to better target restricted assessment resources.
     Further analysis of the Western Zone orange roughy fishery is required. Catch per shot data are the main
     data available but need careful filtering to be representative of the spatial structure and changing fishing
     patterns in the fishery.
     Analysis of orange roughy otoliths from juvenile roughy caught on the smooth ground is necessary to assist
     interpretation of recent recruitment variability. Collection and analysis of orange roughy otoliths from the
     Cascade Plateau and Western Australia is necessary to provide baseline information in those areas now that
     fishing effort is increasing.




     168                                                                          SEF Species Summary 1999
APPENDIX A: ORANGE ROUGHY RECORDED CATCH HISTORY (TONNES) --SEF
CATCHES ONLY

                LOGBOOK DATA                                                    BEST ESTIMATE
YEAR            EAST    SOUTH                   WEST           LOSS             EAST      SOUTH            WEST

1985                  0              58                               0.3              0         75
1986                 33             631                               0.3             43        820
1987                310             353                               0.3            403        459
1988               1922             469                               0.3           2499        610
1989              18364            7620                               0.3          23873       9906
1990              16228           24801              801              0.3          21096      32241             881
1991               9547           11526              656              0.2          11456      13831             722
1992              13470           14183             1134              0.1          14817      15601            1247
1993               4335            5305             1078              0.1           4769       5836            1186
1994               1682            4353              927              0.1           1850       4788            1020
1995               1959            2159             4118              0.0           1959       2159            4118
1996               1998             802             1320              0.0           1998        802            1320

NB 1992 data adjusted for under reporting
   1993 data adjusted for misreporting of Eastern zone catches as Southern zone catches

SEF 1984-1988 SEF Verified Catch data. 1989-1991 SEF Logbook. 1992-1996 SEF2 for Eastern, Southern and Western zones.




Orange Roughy                                                                                                       169
                                10000
                                                                Eastern Management Zone

       Total catch (tonnes)
                                         8000

                                         6000

                                         4000
                                                                                                                 actual / approved TAC
                                         2000

                                                        0
                                                                 1992     1993          1994      1995    1996       1997       1998
                                                                                                 Year




                                12000                            Southern Management Zone
         Total catch (tonnes)




                                          8000



                                          4000                                                                     actual TAC
                                                                                                approved TAC

                                                        0
                                                                 1992     1993          1994      1995    1996        1997      1998
                                                                                                  Year




                                                       2500
                                                                Western Management Zone
                                Total catch (tonnes)




                                                       2000                                                                  actual TAC

                                                       1500
                                                                                                                                 approved TAC
                                                       1000


                                                       500


                                                            0
                                                                   1992          1993          1994      1995         1996        1997      1998
                                                                                                         Year



Figure I Total annual verified catches of orange roughy in each management zone
         calculated from the quota monitoring system (SEF2), and actual and
         approved total allowable catches (TAC)




170                                                                                                                  SEF Species Summary 1999
                                                                                                                                                                                                                 3.50



                                          stand ardised catch rate (t/sh ot)




                                                                                                                                                                             stand ardised catch rate (t/shot)
                                                                                               4.00
                                                                                                                                 non-w inter                                                                                                     non-w inter
                                                                                               3.50                                                                                                              3.00
                                                                                                                                 w inter                                                                                                         w inter
                                                                                               3.00                                                                                                              2.50
                                                                                               2.50                                                                                                              2.00
                                                                                               2.00
                                                                                                                                                                                                                 1.50
                                                                                               1.50
                                                                                                                                                                                                                 1.00
                                                                                               1.00
                                                                                               0.50                                                                                                              0.50

                                                                                               0.00                                                                                                              0.00
                                                                                                      88    90   92    94         96         98                                                                         88     90   92     94        96    98


                                                                                                 (a) Maatsuyker                                                                                                              (b)Pedra Branca
                                                            standardised catch rate (t/shot)




                                                                                                1.20

                                                                                                1.00

                                                                                                0.80

                                                                                                0.60

                                                                                                0.40

                                                                                                0.20

                                                                                                0.00
                                                                                                       88   90    92   94          96        98


                                                                                           (c)South West Tasmania



                                   4.50                                                                                                                                                           0.80
                                                                                                                                                  standardised catch rate(t/shot)




                                                                                                                                                                                                                                                                far w est
standardised catch rate (t/shot)




                                   4.00                                                                                                                                                           0.70
                                   3.50                                                                                                                                                                                                                         King Island
                                                                                                                                                                                                  0.60
                                                                                                                                                                                                                                                                West Tas
                                   3.00
                                                                                                                                                                                                  0.50
                                   2.50
                                                                                                                                                                                                  0.40
                                   2.00
                                                                                                                                                                                                  0.30
                                   1.50
                                                                                                                                                                                                  0.20
                                   1.00
                                   0.50
                                                                                                                                                                                                  0.10

                                   0.00                                                                                                                                                           0.00
                                          88                                                      90        92    94        96          98                                                                         88          90     92        94         96        98




                                   (e) St. Helens area                                                                                                                                                            (f) Western zone areas



                                   Figure II Average annual standardised catch rates of southern zone (a,b, and c), eastern zone (e) and
                                             western zone (f) orange roughy




                                   Orange Roughy                                                                                                                                                                                                                              171
172   SEF Species Summary 1999
Orange Roughy   173
      REDFISH

1.    AFMA'S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS

        Objectives
        Ongoing
     1. To ensure that the redfish resource is utilised in manner consistent with the principles of ecologically
        sustainable development.

        Immediate objective
     2. To develop a mechanism to forecast future catches from the fishery.

        Redfish abundance has fluctuated considerably in recent years. This appears due to a combination of
        availability and recruitment. The development of a recruitment index for redfish would be useful in
        forecasting future catches and determining how much of the variation in redfish abundance can be
        attributed to recruitment.
     3. To ensure that the spawning biomass of redfish does not significantly decline below its 1994 level.

        This objective is regarded as appropriate since the current spawning biomass and original spawning
        biomass are unknown. In the absence of such information a precautionary approach has been adopted that
        attempts to maintain the status quo while biomass is determined.
     4. To maximise the economic efficiency of the redfish fishery.
     5. To implement effective and efficient fisheries management on behalf of the Commonwealth.

        Strategies
        The above objectives will be achieved by:
     1. setting a TAC for the Commonwealth managed portion of the fishery that:
                maintains the catch per unit effort (CPUE) in the fishery above its lowest annual average level from
                 1986 to 1994
                [Note: in the absence of estimates of current or initial spawning biomass an assumption has been
                made that a relationship exists between CPUE and trends in abundance and biomass, however,
                availability of redfish must also be taken into account]
           (objectives 1 & 3)
     2. prioritising redfish research in relation to other SEF quota species:
               SETMAC has given a high research priority rating to this species
           (objectives 1, 2, 3, 4 & 5)
     3. data collection
               (i)   obtaining estimates of catch, catch rates and monitor shifts in effort and changes in fishing
                     practices
               (ii) monitoring of length distributions in commercial catches and undertake ageing as required to
                    refine estimates of:
                           the spawning biomass at the onset of significant commercial fishing
                           the current spawning biomass of the fishery
     4. determine a relative recruitment index
        (objectives 1, 2 & 3)
     5. undertake economic research on the fishery to calculate GVP and monitor market prices for redfish
        (objective 4)

        Performance indicators
     1. That the current annual CPUE for the fishery is above its lowest annual average level from 1986 to 1994
        [Note that if CPUE declines below 1986 - 1994 levels this would not necessarily result in a reduction in the


     174                                                                             SEF Species Summary 1999
          TAC but would require a report to be made on the possible causes of the decline (within 12 months of the
          decline being brought to the attention of SEFAG/AFMA). The report would form the basis of discussion as
          to whether management arrangements, including TACs, for redfish needed to be reconsidered.]
            (strategy 1)
     2. That a recruitment index for the fishery has been developed
        (strategy 3)
     3.   Data relevant to the annual assessment of redfish has been collected and analysed, and considered by
          SEFAG
          (strategies 3 & 4)

     *Important Note:

     The Redfish Assessment Group (RAG) was established in 1997. Through discussions at RAG meetings, it
     was agreed that these is considerable doubt that the specific wording of the current immediate objectives,
     strategies and performance indicators for this fishery are appropriate. The RAG has focussed on the
     following two of the performance indicators.

     CPUE
     The RAG is satisfied that until better models have been developed that can provide superior indicators of
     abundance, CPUE should be used as a performance indicator. However the RAG considers that a CPUE
     derived from a ‗standard fleet‘ (described in the analysis by Chesson and Whitworth in Appendix 5) is
     superior to a performance indicator which is based on ―CPUE for the fishery‖. The RAG also considers that
     rather than comparing the CPUE with ―its lowest annual average level from 1986 to 1994‖ it is more
     appropriate to compare the CPUE of the standard fleet with an ‗indicator‘ catch rate (of approximately 100
     kg per hour) for this fleet in the late 1980s - this being a period of low catch rates from which the fishery
     later improved. The RAG agreed to use the following interim performance indicator in place of
     performance indicator 1, above.

             That the ‗standard fleet‘ CPUE remains above 100 kg per hour.

     Recruitment index for the fishery
     The RAG noted that in recent years the structure of the redfish catch had a distribution such that the catch
     could probably be considered as a defacto recruitment index. As a consequence, and due to:
     (1) the difficulty of specifying an acceptable method to provide a recruitment index, and
     (2) progress is being made towards a model which should supersede the need for a recruitment index,
     the need for this performance indicator is questioned.


     The RAG wishes to emphasise that the above suggestions should not be taken to be the final performance
     indicators for the redfish stock. A formal revision of the management objectives, strategies and
     performance indicators will be undertaken through consultation with AFMA, SETMAC, SENTMAC and
     the RAG.

     AFMA will undergo a process of refining the more generic management objectives for each species and the
     fishery as a whole as part of developing a process of overall Management Strategy Evaluation.

2.    STOCK STRUCTURE AND LIFE HISTORY
     Redfish, Centroberyx affinis (also known as nannygai) occur throughout southern Australia and in New
     Zealand (Rowling 1994). Other species of Centroberyx and some Beryx spp. look similar to C. affinis and
     may also be landed from time to time; however, they are considered to be only a minor component of the
     catch designated as redfish.
     No stock discrimination studies have been done in Australia but tagging studies (Rowling 1990)
     suggested a single unit stock of redfish off NSW. More recent studies of mean length at age suggest
     differences in growth rates between the ‗northern‘ and ‗southern‘ sectors of the fishery off eastern
     Australia, but more analysis is required to determine the significance of these findings to redfish stock
     structure. For the purpose of this stock assessment, it has been assumed that there is only one stock of
     redfish in the SEF.


     Redfish                                                                                                     175
     It is now well established that redfish are a slow growing species which may live more than 35 years.
     The breeding biology of redfish remains poorly documented. They are thought to mature between five
     and seven years of age. Spawning apparently occurs on continental shelf grounds in late summer and
     autumn throughout much of the range of the species, and there are no known spawning migrations. No
     estimates of fecundity are available. Juveniles commonly occur in the larger coastal bays and nearshore
     reefs, while adults are more abundant along the edge of the continental shelf and upper slope with peak
     abundance at depths of 150 to 250 m.

3.    THE FISHERY


     Brief history
     The earliest catches of redfish were made by the steam trawler fleet which began operating in 1915,
     however most redfish were discarded at sea as these boats principally targeted tiger flathead. Catches
     and catch rates of flathead declined during the period 1930-34, and Danish seiners began entering the
     fishery in 1936. However, Danish seining was not as effective as otter trawling for catching redfish, and
     the market acceptance of redfish remained low. When tiger flathead catches failed to recover after the
     war as expected, the steam trawlers began landing increased quantities of other species. Landings of
     redfish increased rapidly, from less than 500 t in 1946 to a peak of 2500 t in 1949, after which redfish
     catches declined rapidly to about 500 t by 1952. Most of these fish were taken on continental shelf
     grounds between Eden and Sydney, and an analysis of logbook data showed that catch rates for redfish
     declined by over 70% during this period. The quantities of redfish caught and discarded at sea prior to
     this period are not known.
     Industry noted that during this immediate post-war period market conditions were strong for all domestic
     fish species, but deteriorated rapidly when the Australian market was opened to imports of frozen fish
     from 1952 onwards. The late 1950s and early 1960s were characterised by small, incidental redfish
     catches as steam trawlers were displaced by Danish seiners as the main units in the fishery.
     During the 1960s the Danish seine fleet began converting to otter trawling. Modern diesel powered
     trawlers were predominant in many ports by the mid 1970s, and Danish seiners had all but disappeared
     from the fishery by the early 1980‘s. During the 1970s trawling extended to the upper continental slope
     (to depths of 600 m), mainly targeting gemfish (Rexea solandri). Large incidental catches of redfish
     were taken on upper slope grounds while targeting gemfish. These fish were generally larger than those
     taken on continental shelf grounds and had a higher market acceptance. However, a very significant
     proportion of the redfish catch continued to be discarded at sea due to oversupply of the market. Redfish
     consignments to the Sydney Fish Markets increased to 2400 t in 1980 as effort levels increased and
     markets gradually improved. Landings fluctuated between 1500 t and 2000 t per year until 1985.
     Despite continuing high effort levels, recorded landings of redfish declined to less than 1000 t in 1989.
     Landings increased again in the early 1990s reaching a peak of just over 2000 t in 1993.
     Individual transferable quotas (ITQs) were introduced in 1992 with the total allowable catch (TAC) for
     redfish of 600 t reflecting concern over the decline in catches in the late 1980s and the indications from
     early stock assessments. However, the implementation of quota management coincided with a substantial
     increase in the availability of redfish, which resulted in calls for the TAC to be increased. Enforcement
     of the TAC was compromised as some redfish caught in Commonwealth waters were reported as coming
     from State waters to avoid being counted against quota (in fact in 1993 when the TAC was 600 t the
     actual landings of redfish were around 2000 t). In recognition of the increased availability of redfish, the
     TAC was increased to 1000 t in 1994 and to 1700 t in 1995. The ―state waters‖ loophole was reduced in
     1994 with the imposition by NSW of a 100 kg trip limit for redfish caught in state waters south of
     Barranjoey Point.
     Discarding and high-grading have been features of the fishery for redfish since its inception. The rate of
     discarding is known to have varied over time but only since 1993 have actual data been available from
     observers participating in Scientific Monitoring Programs and the NSW Bycatch Study (Liggins, 1996).
     Between 1993 and 1995 overall discard rates were estimated to be around 50 per cent by weight, but this
     rate declined to less than 10 per cent during 1997.

     Current situation
     The 1998 agreed TAC remained at 1750 t with the actual allocated TAC being 2042 t. The total landed


     176                                                                         SEF Species Summary 1999
       catch from SEF2 records in 1998 was 1770 t, of which 1752 t was reported as taken in Commonwealth
       waters and 18 t was recorded from State waters. The overall discard rate for 1998 was estimated at 32 per
       cent giving an estimated total catch of approximately 2600 t. In 1998 approximately 15 t of redfish were
       landed by NSW licensed fishers north of Barranjoey Pt.
       The gross value of recorded landings in State and Commonwealth waters by Commonwealth boats in 1998
       was estimated to be about $1.7 million. A significant proportion of landings, especially of the smaller fish,
       was processed into ‗surimi‘ paste at a comparatively low return rate (c. 50c/kg ) to the catchers.
       In general, no concerns were raised about the redfish stock at the 1998 port meetings. Operators again
       commented that the landings of redfish were market driven, and that redfish had been reasonably abundant
       during the 1997/98 summer. Port visits were not conducted in NSW ports during 1999, however the general
       advice from industry members of the Redfish Assessment Group was that redfish had remained reasonably
       available during late 1998, and the 1998 TAC had in fact been caught.

4.     PREVIOUS ASSESSMENTS
       A comprehensive assessment of redfish carried out in 1993 concluded that stock biomass was low in the
       late 1980s (less than 20% of that in 1969) but that increases in catch and CPUE from 1990 to 1993,
       especially of small fish, suggested an increase in recruitment. A yield per recruit analysis based on
       growth and mortality rates accepted at that time indicated that better yields and value could be obtained if
       fish were caught at a greater size and age.
       Stock assessment reports were produced in 1994 and 1995, but these mainly documented new data and
       comments from industry. No substantial analyses were carried out. There was no stock assessment report in
       1996. During the period 1993 to 1996, length frequency data and quantitative information on discard rates
       were collected by onboard observers. The size compositions of both retained and discarded segments of
       the catch were determined for selected ports. There was also a substantial increase in the amount of ageing
       information, including validation of the ageing method using the ―bomb‖ radiocarbon method and results
       from examination of otoliths of tagged redfish recaptured after long periods at liberty, up to ten years.
       Analysis of the ageing data also produced evidence of regional differences in growth rates.
       In 1995 the average catch rate (kg/hr for shots containing redfish), estimated from logbook data, fell
       below the minimum rate observed between 1986 and 1994. This was interpreted as triggering AFMA‘s
       requirement for a report into the possible causes of the reduction (Performance Indicator 1). In April
       1997 a workshop was held to discuss the research findings for redfish which had accumulated since 1993.
       This led to the formation of the Redfish Assessment Group (RAG), chaired by Kevin Rowling, and
       comprising representatives from AFMA (David Alden), BRS (Jean Chesson) and industry (Peter Bell,
       Rocky Lagana and Tony Lavalle). The RAG met four times during late 1997 and early 1998, the main
       objective of these meetings being to receive industry advice about the probable levels of discarding
       during the course of the redfish fishery, and to incorporate this information in an updated assessment of
       the status of the redfish stock.
       A full stock assessment report was not produced during 1998, but a summary report was discussed at the
       SEFAG plenary meeting in June 1998. The findings and implications of the assessment had not been
       fully discussed by the RAG members, so SEFAG considered it as a ‗preliminary‘ assessment. The cohort
       analyses for both the 40% and 80% discard scenarios found a long term decline in redfish biomass had
       occurred since the commencement of the modern trawl fishery in the 1960s (these results were consistent
       with the findings of the 1993 assessment). Industry members of the RAG were not comfortable with the
       poor indications of stock status in recent years, as the low biomass estimates did not concur with their ―at
       sea‖ observations about the status of the stock. SEFAG members queried a number of technical aspects
       of the cohort analyses, including the ‗terminal F‘ estimation, the ‗tuning‘ period used and the effect of the
       ‗plus group‘ specified in the analyses. Industry members of SEFAG were also critical of the biomass and
       recruitment estimates for the most recent years (both of which were assessed by the analyses to decline
       rapidly after 1993). Given the uncertainties surrounding the preliminary assessment, SEFAG did not
       believe the results should be used as a basis for management decisions.

     5. 1999 ASSESSMENT

       Recent developments
       Following the comments about the preliminary assessment at the 1998 SEFAG Plenary meeting, work was


       Redfish                                                                                                    177
undertaken by Dr. K. Allen to address the main points raised. Early in 1999 data became available from the
first year of operation (1998) of the redesigned ISMP monitoring project.

Assessment process
The Redfish Assessment Group met in March and May 1999 to review the results of the work on the cohort
analyses, and to discuss updated CPUE estimates and the results from the onboard monitoring program. As
in 1998, there was limited time and resources for undertaking thorough analyses and discussions. In May
1999 the redfish data were also incorporated in an initial dynamic population model using the generalised
AD Model Builder framework developed by Ray Hilborn.

Methods
In examining the points raised by SEFAG about the cohort analyses, Dr. Allen discovered that the trends in
biomass estimates generated by cohort analysis were extraordinarily sensitive to the value of the natural
mortality rate M assumed in the analysis. By assuming that the stock was more or less at equilibrium
during the very early years of the modern fishery (the early 1960s) Dr. Allen was able to estimate the most
probable value of M which resulted in a ‗neutral‘ surplus production during these early years.
The standardised CPUE series for redfish was updated to include the data for 1998, using the same
protocols as were agreed for the analysis to 1997 - a standard fleet of 10 boats across the fishery, and a core
fleet of 5 Ulladulla boats for which total (retained + discarded) catch rate could be confidently estimated.
The performance of the main catching vessels was also briefly examined by assessing the aggregate catches
of groups of five vessels in a range of years since TAC management was introduced (1992).
The ―Coleraine‖ software package was used to develop a preliminary age and length structured dynamic
model which was fitted to the CPUE and size composition data available for redfish for the period 1980 to
1997.

Results
Cohort Analyses
The analyses performed by Dr Allen suggested that the most appropriate value for M for redfish was about
0.15, not 0.1 as had been used in previous assessments. This seemingly small change in M resulted in a
very significant change in the relative productivity of the redfish stock, and therefore in the biomass
estimates produced by the cohort analyses. The results for a number of cohort analyses which used
different values for M and varying periods for ‗tuning‘ the catchability (Q) were reviewed.
The discard regime significantly affects the estimate of initial biomass (note that for redfish ‗recruited‘
biomass and ‗mature‘ biomass are very similar, as most redfish in the catch are assumed to be mature). For
M=0.14, initial biomass was estimated to be about 39000 t for the 40% discard scenario, and about 54000 t
for the 80% discard scenario. Recent (1997) recruited biomass was estimated to be 10334 t for both discard
series if 1988-1990 was used as the tuning period. If a longer tuning period (1970-1990) was used the
estimates of recruited biomass in 1997 were 8048 t for the 40% scenario and 5404 t for the 80% scenario.
Using the more recent (1993-1995) period to tune Q resulted in much lower recent biomass estimates (2872
t for both scenarios, for M=0.14). It would seem to be inappropriate to use a period after the introduction
of quotas to estimate the catchability, even though this is a recent period for which reasonable data are
available.
Accepting that the initial analyses using M=0.14 and the 1988-1990 tuning period result in reasonable
descriptions of the redfish population, the biomass and recruitment trajectories from analyses using these
values are compared with the results presented in the 1998 assessment in Figures 1 to 4. It is apparent that
the recent biomass estimates are highly sensitive to the catchability used in the analysis (note that the
biomass estimates for the last couple of years of the assessment are the most uncertain because of the small
number of observations contributing to the estimates). More discussion of these results is required before
the RAG can decide on an appropriate value to use for catchability (Q). The general pattern of a significant
decline in recruited biomass of redfish since the 1960s persists in the recent analyses. Lack of time
prevented updating the cohort analyses to include the data for the 1998 year, however the inclusion of these
data would be unlikely to result in a significant change to the patterns shown in Figures 1 to 4.
CPUE Analyses
The ―standardised‖ catch rate series for redfish was updated using data from the SEF1 logbook according


178                                                                         SEF Species Summary 1999
to the specifications developed last year. The results for the core fleet of Ulladulla vessels are shown in
Figure II. The catch rate (total redfish catch in kg per hour trawled for all hours fished in the ‗redfish‘
depth zone of 50 to 400 m) increased again in 1998, to 212 kg/hr, slightly less than the recent peak catch
rate of 276 kg/hr observed in 1992. The RAG considered the distribution of redfish catch amongst the top
catching vessels in the years 1993 and 1996 - 1998, and found that the top 10 catching vessels accounted
for 50 - 60 per cent of redfish landings during this period. In 1998 the top ten catching vessels accounted
for about 1200 t of redfish, about 70 per cent of landings in that year. The RAG noted that in 3 of the 4
years examined, the top 5 catching vessels landed between 850 and 900 t of redfish in aggregate.
“Coleraine” Model
In early May 1999, Jeremy Prince (Biospherics), Tony Smith and Sally Wayte (CSIRO) attended a stock
assessment and modelling workshop run by Prof. Ray Hilborn where they commenced development of a
dynamic population model for redfish, using the same data as were used for the 1998 assessment. The
results available to date suggest recent exploitation rates in the range 0.05 - 0.10, and a large spike in
recruitment in 1992 and 1993. Mature biomass is estimated to have declined from 50,000 t to 30,000 t
between 1980 and 1997. However these results are described as very preliminary and the behaviour of the
model is unstable. Jeremy Prince is continuing the development of this model, which is seen as a useful
tool for better understanding the data available for redfish.




                  FIGURE 1. Redfish Biomass Estimates - 80% Discard
             60000                    Scenario
                                                                                    1998 Assessment
             50000                                                                  M=0.14, Q(88-90)

             40000
    Tonnes




             30000

             20000

             10000

                0
                     1960

                            1963

                                   1966

                                          1969

                                                 1972

                                                        1975

                                                               1978

                                                                      1981

                                                                             1984

                                                                                      1987

                                                                                             1990

                                                                                                    1993

                                                                                                           1996




                                                               Year




Redfish                                                                                                           179
                                  FIGURE 2. Redfish Biomass Estimates - 40% Discard Scenario

                            40000
                                                                                                                       1998 Assessment
                            35000
                                                                                                                       M=0.14, Q(88-90)
                            30000

                            25000
  Tonnes




                            20000

                            15000

                            10000

                             5000

                                    0
                                        1960

                                                  1963

                                                            1966

                                                                     1969

                                                                              1972

                                                                                       1975

                                                                                                1978

                                                                                                        1981

                                                                                                                1984

                                                                                                                        1987

                                                                                                                               1990

                                                                                                                                      1993

                                                                                                                                             1996
                                                                                                Year




                            FIGURE 3 Redfish Recruitment - 80% Discard Scenario

                            35
                                                                                               1998 Assessment
  Millions of 3 Year Olds




                            30                                                                 M=0.14, Q(88-90)
                            25

                            20

                            15

                            10

                             5

                             0
                                 1960

                                           1963

                                                     1966

                                                              1969

                                                                       1972

                                                                                1975

                                                                                        1978

                                                                                                 1981

                                                                                                         1984

                                                                                                                1987

                                                                                                                        1990

                                                                                                                               1993

                                                                                                                                      1996




                                                                                       Year




180                                                                                                                                          SEF Species Summary 1999
                                          FIGURE 4. Redfish Recruitment - 40% Discard Scenario

                                   30
         Millions of 3 Year Olds                                                  1998 Assessment
                                   25                                             M=0.14, Q(88-90)

                                   20

                                   15

                                   10

                                   5

                                   0
                                        1960

                                               1963

                                                      1966

                                                             1969

                                                                    1972

                                                                           1975

                                                                                     1978

                                                                                            1981

                                                                                                   1984

                                                                                                          1987

                                                                                                                 1990

                                                                                                                        1993

                                                                                                                               1996
                                                                                    Year




     Uncertainties in the assessment

     The stock structure of redfish has yet to be resolved. The observed differences in growth rate between
     ‗northern‘ and ‗southern‘ fish were not investigated further during 1998, and remain a priority for study
     in the coming year. The opinion of fishers is that it is unlikely there are two separate stocks of redfish.
     The current assessment assumes a single stock in the area from Lakes Entrance to Sydney.

     The current biomass remains very uncertain. Biomass estimates from the cohort analyses suggest a range
     from around 3000 to 10000 t, depending mainly on the ―tuning‖ period used in the analysis. Initial results
     from the ‗Coleraine‘ analysis suggest a recent biomass of around 30000 t, although this estimate is very
     preliminary and should be interpreted with caution.

     Recent levels of recruitment are not well specified, and no recruitment index is available (although the
     fishery is fishing pretty hard against recruitment, and so catch might be the best available index of
     recruitment).

6.    IMPLICATIONS FOR MANAGEMENT
     The standardised CPUE estimate for 1998 does not trigger AFMA‘s current performance indicator
     concerning redfish catch rates. Even though catch rate has shown a recent increase, it is far from certain that
     catch rate provides an accurate index of stock abundance for redfish. There are signs that recruitment
     levels observed for the early 1990‘s may not be sustained in recent years. Uncertainty about the current
     stock size and recent recruitment levels suggests that continuing to catch around 2000 t per year (which is
     towards the upper range of historic redfish catch levels) is not likely to be a ―risk-averse‖ strategy.
     The best available assessment indicates that the mature biomass of redfish continues to be around 20% of
     the unexploited biomass level, and is therefore in the region considered by most biologists and fishery
     managers to be at risk from recruitment over-fishing. However the risk of recruitment failure cannot be
     evaluated. It is also pertinent to observe that the mature biomass of redfish has apparently been at a
     relatively low level since the late 1980s, with no consequent problems for recruitment apparent to 1997.
     The mean size of redfish caught by the trawl fishery continues to decline, and is now less than 20 cm LCF.
     Previous yield-per-recruit analyses suggested that better yields and economic returns could be achieved by
     increasing the size at first capture of redfish, and this remains a viable objective for management. However,
     this will not be efficiently achieved by alteration of the level of the TAC, but requires appropriate
     adjustment of the selectivity of the fishing gear. The recently commenced FRDC funded research program
     on reducing discards in the SEF is to address selectivity issues relevant to redfish, including reducing the
     capture of small fish.




     Redfish                                                                                                                          181
7.    RESEARCH NEEDS
      A better spatial and temporal description of the fishery is required to support the assessment and allow
       investigation of appropriate harvest strategies.

      The implications for the assessment of the observed differences in growth rate between the ‗northern‘
       and ‗southern‘ sectors of the fishery need to be assessed. This may entail modelling the fisheries in the
       two areas separately.

      The reproductive biology of redfish remains poorly understood. Size at first maturity and relative
       fecundity by size/age are inadequately described.

      Previous yield per recruit analyses need to be respecified in the light of the new population parameters
       (M=0.15). The economic benefits of increasing the size at first capture also need to be determined.

      A fishery independent biomass estimate would help reduce uncertainty about current biomass, and
       studies aimed at estimating the abundance of redfish on non-trawlable grounds would benefit our
       understanding of possible ‗spawning refuges‘.
      Further development of a ―customised‖ stock assessment model for redfish is required.
      Development of methods of harvest strategy evaluation taking into account fluctuations in redfish
       catches and catch rates, and size at first capture.




     182                                                                       SEF Species Summary 1999
                       2000                                                                            actual TAC
                                                                                                           approved TAC

Total catch (tonnes)
                       1500


                       1000


                       500


                                           0
                                                          1992   1993   1994   1995   1996   1997   1998
                                                                               Year



   Figure I Total annual verified catches of redfish calculated from the quota monitoring system
           (SEF2), and actual and approved total allowable catches (TAC)



                                                    300
                        standardised cpue (kg/hr)




                                                    250

                                                    200

                                                    150

                                                    100

                                                    50

                                                     0
                                                          85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

   Figure II Average annual standardised catch rates of redfish calculated using the core fleet of
             Ulladulla boats




   Redfish                                                                                                                183
184   SEF Species Summary 1999
ROYAL RED PRAWN

 1.   AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE CRITERIA
      Objectives
      Ongoing
 1.   To ensure that the royal red prawn resource is utilised in a manner consistent with the principles of
      ecologically sustainable development.
      Immediate objective
 2.   To ensure that the spawning biomass of royal red prawn does not significantly decline below its current
      (1995) level:
           current jurisdictional boundaries and varying approaches to management by the States and
            Commonwealth need to be reconciled if this objective is to be achieved;
           noting that a significant catch is taken north of Barranjoey Point, NSW.
 3.   To maximise the economic efficiency of the royal red prawn fishery.
 4.   To implement effective and efficient fisheries management on behalf of the Commonwealth.
      Strategies
      The above objectives will be achieved by:
 1.    setting a TAC for the Commonwealth managed portion of the fishery that:
           that maintains catch per unit effort (CPUE) above its lowest annual average level from 1986 to
            1994
            [Note: the TAC would currently only apply to the trawl sector of the fishery within the SEF,
            excluding the southern Remote Zone]
            (objectives 1 & 2)
 2.   managing all sectors of the royal red prawn fishery in a complementary manner
      (objectives 1 & 4)
 3.   prioritising royal red prawn research in relation to other SEF species:
           SETMAC has given a low research priority rating to this species
            (objectives 1, 2, 3 & 4)
 4.   data collection
      (i)   obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing practices
            (Objectives 1 & 2)
 5.   undertaking economic research on fishery to calculate GVP and monitor market prices for royal red
      prawn (Objective 3)

 Performance indicators
 1. That the current annual CPUE for the fishery is above its lowest annual average level from 1986 to
     1994 (Strategy 1)
 2.   That all sectors of the fishery are managed in a complementary manner (Strategy 2)
 Data relevant to the annual assessment of royal red prawn has been collected and analysed, and considered
     by SEFAG (Strategies 1, 3, 4 & 5)
 The actual trawl catch relative to the trawl TAC (Strategy 1)




      Royal Red Prawn                                                                                              185
2.   STOCK STRUCTURE AND LIFE HISTORY

     Royal red prawn are distributed between 26oS and 36oS off eastern Australia and also occur off north-
     eastern Queensland, South Australia and northern Western Australia. Nothing is known of stock structure
     across Australian waters. Within the SEF, royal red prawns appear to comprise a common stock off
     NSW that straddles the Barrenjoey line.
     The species occurs mainly at depths between 350 and 550 m. Off NSW, smaller immature prawns occur
     in the southern parts of their range and mature breeding prawns occur on the more northern grounds.
     Royal red prawns appear to live to at least three years of age, based on distinct size classes in the catch.
     However these separate size classes may result from multiple spawnings within a year.

3.   THE FISHERY
     Current situation
     The 1998 SEF2 total was 282 t (214 t Commonwealth, 68 t State). The catch from
     Commonwealth water represented 34% of the actual TAC of 625 t and 43% of the agreed
     TAC of 500 t. The 1999 agreed TAC is 500 t, with an actual TAC of 611 t. Targeting of
     royal red prawn is market driven and in 1998 fishing effort and SEF catch decreased in
     comparison to 1997. A significant amount of the SEF2 catch is reported as coming from
     State waters, north of the Barrenjoey line.
     In general, Industry comments indicated the fishery was stable but environmentally driven,
     particularly by the East Australian Current. A major issue with Industry is the ―Barrenjoey
     line loophole‖ , where significant catches of royal red prawn are taken north of the SEF
     causing problems with lease prices as well as mis-reporting of catches from south of the
     line. Catches are almost entirely market driven and operators have to compete at the
     Sydney markets with operators from north of Barranjoey.


4.   PREVIOUS ASSESSMENTS
     The previous assessment concluded that the exploited royal red prawn stock was in an
     apparent steady state under the levels of fishing effort applying during the late 1980's, as
     indicated by stable annual catches and stable CPUE. Lack of knowledge of that part of the
     stock outside the SEF boundary, and of biological parameters such as natural mortality rate,
     contributed to uncertainty of the assessment.

5.   1999 UPDATE
     There was no formal assessment of royal red prawns undertaken during 1999. However,
     1998 logbook and ISMP data were incorporated into this summary.
     Catch and effort
     Virtually all of the royal red prawn catch comes from Eastern Zone A. The 1998 SEF2
     total was 282 t (214 t Commonwealth, 68 t State). The catch from Commonwealth waters
     represented 34% of the actual TAC of 625 t and 43% of the agreed TAC of 500 t. It
     represents a 12% increase compared to 1997. The 1999 agreed TAC remained at 500 t,
     with the actual TAC being 611 t.
     The mean unstandardised catch rate (based only on shots containing royal red prawn) again
     fell in 1998 to a record low of under 60kg/hr. Catch rates over the last decade have
     increased from a low of around 60 kg/hr in 1986 to a peak of around 140kg/hr in the early
     1990s before steadily declining back to about 60 kg/hr in 1998. It is uncertain whether this
     cycle reflects a change in abundance of royal red prawns over this time.
     Size composition
     The carapace length of royal red prawns ranges between 15 and 30 cm with a mode around
     22-23 cm. The size of prawns tends to increase the further north they are caught.
     Discarding
     Discarding rates are generally low. During 1998, the discard rate was around 6%. ISMP
     observers reported that catches were low during 1998 and that operators often discarded all


     186                                                                         SEF Species Summary 1999
     of their prawn catch unless a minimum of around xx kg was caught in any shot. This may
     have resulted in an increased discard rate in 1998 compared to previous years.

     Port visits
     Operators again stressed that targeting is market driven. As previously reported, the
     abundance of royal red prawns appears to be environmentally driven, particularly
     influenced by water currents and temperatures. There was concern that the management fee
     is based on Sydney market prices, not processor prices as with blue grenadier.

     Prices
     In 1998, the gross value of recorded landings of royal red prawns was estimated to be about
     $0.88 million. Prices averaged $3.70/kg on the Sydney Fish Market. Prices are generally
     higher in spring leading up to summer.

6.   IMPLICATIONS FOR MANAGEMENT
     The annual catch is comparatively stable at between 300-400 t and is largely market driven.
     The main implications for management revolve around the lack of any ongoing research on
     the royal red prawn fishery, and resultant uncertainty about the current stock situation.
     There is no biological monitoring program in place for commercial catches. Stock status
     remains unknown and will continue to be so in the absence of targeted research.
     Although recent SEF fishing effort targeting on royal red prawns has not been high, the
     potential exists for effort to increase in response to market demand, as current catch levels
     are not constrained by the TAC. Misreporting across the Barrenjoey line constitutes a SEF
     monitoring problem, but the real management problem is that of a common stock straddling
     two jurisdictions. The stock is also thought to spawn north of the SEF and recruit
     southwards. There were anecdotal industry reports of increased fishing effort and
     exploitation north of the SEF. The 50% increase from 1996 to 1997 in the volume of royal
     red prawns sold at the Sydney Fish Market, despite the downturn in SEF landings, supports
     industry‘s claim. Complementary management controls are not yet in place north of the
     SEF and, if landings from this area rise significantly, a higher priority should be given to
     resolving this issue.

7.   RESEARCH NEEDS
     Monitoring of directed fishing effort, trends in CPUE and size frequencies throughout (i.e.
     north and south of Barrenjoey) the royal red prawn fishery off NSW should be instigated.
     Information on the comparative abundance and size composition of royal red prawn on
     established NSW grounds would also help to clarify stock delineation issues. Stock
     boundaries within the AFZ, and more particularly in the SEF and nearby areas, are poorly
     known.




     Royal Red Prawn                                                                                 187
                                   700
    Total catch (tonnes)
                                   600                                                          actual TAC

                                   500                                                          approved TAC

                                   400

                                   300

                                   200

                                   100

                                         0
                                                  1992   1993   1994   1995   1996   1997   1998

                                                                       Year




Figure I Total annual verified catches of royal red prawn calculated from the quota monitoring
        system (SEF2), and actual and approved total allowable catches (TAC)




                                         160
                                         140
                av. catch rate (kg/hr)




                                         120
                                         100
                                         80

                                         60
                                         40
                                         20
                                             0
                                                 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99



Figure II Avergae annual unstandardised catch rates of royal red prawn




188                                                                                    SEF Species Summary 1999
Royal Red Prawn   189
190   SEF Species Summary 1999
      SCHOOL WHITING

1.   AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
   Objectives
   Ongoing
1. To ensure that the school whiting resource is utilised in a manner consistent with the principles of
   ecologically sustainable development.
   Immediate objective
2. To ensure that the spawning biomass of school whiting does not significantly decline below its current
   (1994) level:
         Management approaches by the Commonwealth need to be reconciled if this objective is to be
          achieved.
3. To maximise the economic efficiency of the school whiting fishery.
4. To implement effective and efficient fisheries management on behalf of the Commonwealth.
      Strategies
      The above objectives will be achieved by:
1. setting a TAC for the Commonwealth managed portion of the fishery that:
       maintains the catch per unit effort (CPUE) in the fishery above its lowest annual average level from
        1986 to 1994
        [Note that there are several stocks within the area of the SEF, and this report only refers to the
        Jervis Bay to Portland stock]
        (objectives 1 & 2)
2. managing all sectors of the school whiting fishery in a complementary manner
   (objectives 1 & 4)
3. prioritising school whiting research in relation to other SEF species:
         in 1998/99, SETMAC gave a high research priority rating to this species
         (objectives 1, 2, 3 & 4)
4. data collection
   (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing practices;
      (ii) monitor length distributions in commercial catches and collect ageing data as required.
           (objectives 1 & 2)
5. undertaking economic research on the fishery to calculate GVP and market prices for school whiting
   (objective 3)
   Performance indicators (1995 - 1998)
1. That the current annual CPUE for the fishery is above its lowest annual average level from 1986 to 1994
   [Note that if CPUE declines below 1986 - 1994 levels this would not necessarily result in a reduction in
   the TAC but would require a report be made on the possible causes of the decline (within 12 months of
   the decline being brought to the attention of SEFAG/AFMA). The report would form the basis of
   discussion as to whether management arrangement, including TACs, for school whiting needed to be
   reconsidered.]
   (strategy 1)
2. That all sectors of the fishery are managed in a complementary manner
   (strategy 2)
3. Data relevant to the annual assessment of school whiting has been collected and analysed, and
   considered by SEFAG
   (strategies 1, 3, 4 & 5)
4. The actual catch relative to the TAC
   (strategy 1)


     Important note:

     School Whiting                                                                                            191
     Through discussions between managers, industry and scientists at the school whiting assessment workshop
     in June 1999, it was agreed that the specific wording of the previous strategies and performance indicators
     relating to pursuit of AFMA‘s ESD objective was inappropriate. In particular using annual average CPUE
     as a performance indicator for the school whiting fishery was considered inappropriate.

     A formal stock assessment was conducted for the first time in 1999. It was also the first time since 1994
     that school whiting data had been extensively examined. If further work is funded during 1999 and 2000
     SEFAG will be in a position to provide some information about the status of the school whiting resource in
     terms of trends in biomass without specific reference to annual average catch rates as a performance
     indicator. Performance indicators will be developed which relate to the probability of being below an
     agreed fraction of a reference biomass level.

     The status of the school whiting resource in 1999 has been assessed by means of trends in relative spawner
     biomass estimated using an assessment model based on catch, CPUE and age-composition data.



2.    STOCK STRUCTURE AND LIFE HISTORY
     Most of the assessment information is based on eastern school whiting, Sillago flindersi which dominates
     the SEF catch. The closely related western school whiting Sillago bassensis is caught in much smaller
     quantities. Formerly, the two species were regarded as a single species. Eastern school, or redspot, whiting
     are found from southern Queensland to south-east South Australia.
     Genetic studies indicate stock structuring within the eastern school whiting population, with at least three
     separate stocks present. Stock boundaries are imprecise, but they are loosely distributed as follows; north of
     Newcastle (NSW), Jervis Bay (NSW) to Portland (Victoria), west of Portland. Dixon et al (1987) noted
     similarities between fish from Tasmania and those from eastern Victoria and postulated a one-way flow of
     larvae across Bass Strait. For management purposes, the Tasmanian fish are considered a separate stock.
     School whiting are mostly demersal and are commonly found on sandy substrates to depths of about 60 m.
     In the SEF, school whiting spawn mainly during summer. They grow rapidly and reach a maximum age of
     about 7 years. School whiting become sexually mature at two years of age. They are benthic feeders.
     Little is known of recruitment, although it is thought to be variable. In the SEF, full recruitment to the
     fishery occurs at 2-3 years of age although 1 year olds are also taken.
     Natural mortality was estimated to be between 0.9 and 1.1 (i.e. between 59-66 per cent per annum) but
     there is considerable doubt about these estimates.

3.    THE FISHERY
     The SEF fishery is based on the Jervis Bay to Portland stock and the bulk of the catch is taken by Danish
     seiners operating from Lakes Entrance and San Remo.

     Current situation
     The 1998 SEF2 landed weight of school whiting was 639 t (419 t in Commonwealth waters and 220 t in
     State waters), which was 26% of the allocated TAC of 2,423 t. It represents a decrease in landings
     compared to 1997 (754 t). The 1999 TAC was reduced to 1500 t, with the allocated TAC being 1,929 t.
     Industry expressed considerable concern regarding the decision to reduce the 1999 TAC by 25%. They
     argued that the decline seen in catches and catch rates did not reflect declining abundance but was due to
     other factors. They were concerned that their perspective wasn‘t adequately taken onto account in the TAC
     setting process. They also stressed that while the Lakes Entrance fleet catches about 70% of school
     whiting, the LEFCOL pool fleet only owns about 50% of the quota. This can give biases in the figures
     comparing catch to the overall TAC. Lakes Entrance seiners also have a voluntary quota based on the
     amount of fish that the LEFCOL can process for export at any one time. The size of fish landed may also
     be influenced by market needs.

     The reasons for the low catches over the last few years were due to market factors , particularly the
     condition of fish due to weed and the impact of the weed in reducing the areas which could be fished..
     Industry targeted flathead during these years and there is a clear inverse signal in the catch and effort data.


     192                                                                           SEF Species Summary 1999
     Only about 4 vessels chased whiting in 1998. Overall the number of vessels operating out of Lakes
     Entrance had declined (20+ to 15) since the peak catches in the early 1990s

     Industry reported that 1999 was the best year in along time with large catches of whiting taken off the
     beaches (according to AFMA figures about 480t, already this year). Large numbers of small whiting were
     reported and it was suggested that this might indicate a strong year class. It was noted that Bass Strait
     seems particularly productive this year with large flathead abundant and squid very abundant with the squid
     fleet working out of Lakes for the fist time.

     Industry reported that since the ocean outfall commenced operations in 1992? few whiting are taken in the
     area.

     ABARE TO UPDATE The gross value of recorded landings of whiting taken by Commonwealth boats in
     both Commonwealth and state waters in 1996 was estimated to be about $1.3 million. This was about 30 %
     lower than the value in 1995, due to a combination of lower landings and lower prices. In 1996, the
     estimated average return to the fisher for school whiting was $1.30/kg, compared to $1.45/kg in 1995.
     Much of the whiting caught by the Danish seine fleet is exported to Japan through the Lakes Entrance Co-
     operative. Other major markets for whiting include Hong Kong, Taiwan and Thailand. In 1996, whole
     frozen whiting exports from Victoria were 562 tonnes (product weight) with an average fob value of
     $1.80/kg, compared with 854 tonnes exported in 1995 at an average fob value of $2.19/kg.

4.    PREVIOUS ASSESSMENTS
     Apart from yield per recruit analyses, considerable uncertainty surrounds yield estimates for this species.
     There were no new developments reported in the 1993 assessment, which noted that catch rates were stable
     between 1986 and 1992, and that exploitation rates were similar to those estimated for the fishery during
     the early 1980s.
     An assessment of school whiting was undertaken in 1994 but this was limited to examination of key
     indicators. Catch data gave little indication of stock status, because the catches were driven by market
     demands. New data was presented from AFMA (SEF2 data), the Central Ageing Facility (age-composition
     data), and the SMP, CSIRO and VFRI (length-frequency data from on-board vessels, surveys and port
     sampling respectively). Trends in SEF logbook catch, effort, and catch rates, age composition from the
     Central Ageing Facility, and length-frequency data, were examined.
     The relative age composition of the catch by the Danish seine fleet at Lakes Entrance was estimated for
     1991-94, using CAF age data and length frequency data from port sampling and the SMP. Total mortality
     was estimated using the log of the abundance of the 4-7 year olds in the derived catch curves for 1991-94.
     The age composition of the Danish seine catch from Lakes Entrance showed fluctuations from a pre-
     dominance of 3 and 4 year olds in 1991, to 2 year olds in 1992, and 3 year olds in 1993 and the start of
     1994. Mortality estimates made from these varied between 1.26 for 1992 to 2.27 for 1994. Although the
     stock in eastern Bass Strait appeared stable, the 1994 assessment was limited. There were no useful
     estimates of current biomass available. With continued collection of ageing data, an estimate would be
     possible in the near future by using age-structured methods such as VPA‘s. Structuring of the stock, high
     grading, and targeting by fishers, are important factors in such assessments for school whiting.

5.    1999 ASSESSMENT

     Recent developments
     The 1999 assessment was based on an ARF-funded project ―School whiting assessment and workshop‖.
     The first formal stock assessment of the school whiting resource was undertaken using age-structured
     modeling based on catch-at-age and fishing effort data.

     Assessment process
     Results of the school whiting assessment were presented at a workshop held at LEFCOL, Lakes Entrance,
     17-18 June. AFMA‘s SEF manager, scientists from MAFRI, CSIRO and industry and 16 school whiting
     fishers attended the workshop. The workshop provided an overview of the data, discussed how
     environmental factors might impact the fishery, and considered the results from an age-structured


     School Whiting                                                                                          193
assessment.

Methods
Danish seine (and trawl) (SEF1) catch and effort data from 1986 to 1998, and quota monitoring (SEF2)
data were examined. Trends in the spatial extent of the fishery were described using GIS. Information on
length frequencies and the retained and discarded catch of school whiting was obtained from ISMP on-
board monitoring data and port-based length-frequency data. GLM analyses were applied to SEF1 data to
provide standardised catch rates. The factors considered in the model were year, depth, month and vessel
and all shots in which some whiting were caught were included in the analyses.
Otoliths collected during 1995 and 1997 (but not aged) were aged by the Central Ageing Facility at the
Marine and Freshwater Resources Institute using standard methods. These data, together with samples
collected during 1998 (as part of the CAF workplan), were combined with size and catch data using
Method 2 of Punt and Smith to provide a time series of catch-at-age data for the years 1991-1998.
ADAPT and Integrated Analysis were used within a Bayesian framework to assess the status of the school
whiting resource. The assessment was based on catch-at-age and fishing effort data. Natural mortality was
set at 0.5. The model was used to estimate time-trajectories of egg production (as a proxy for spawner
biomass) and recruitment (number of 1-year olds each year).

Results
School whiting have a long history of catches in the SEF (Figure 1). Annual landings were generally under
250 t until rapid increases in the mid-1970s. Landings peaked during the early 1990s at over 1500t. About
95% is taken by Danish seiners primarily working from Lakes Entrance. Annual landings have declined in
recent years. Industry have indicated that this is, in part, due to a reduction in the number of vessels and
also more fishing directed at flathead.


                                                School whiting - annual catch (t)

                 2500


                 2000
Catch (tonnes)




                 1500


                 1000


                 500


                   0
                        1947   1951   1955   1959   1963   1967   1971     1975   1979   1983   1987   1991   1995

                                                                    Year

Figure 1 School whiting annual commercial landings, 1947-1998. Source: DPFRG 1947-1985,
SEF1/SEF2 and State catches 1986-1998.
Danish seine catches are dominated by school whiting and flathead (with other species making up 10-20%
of catches) and there is a clear inverse relationship between the two, i.e when whiting catches are high
flathead are relatively lower. Analysis of logbook data shows that this is depth-related. In waters less than
50m deep almost all the target species is whiting. In waters greater than about 80m flathead dominate. The
species composition in shots in depths between 50 and 80 m is about 40% each and other species make-up
20% of catches. Seasonally, whiting catches are highest during autumn (April-May). The area of which
whiting have been caught expanded from 1986 to the early 1990s, and has contracted noticeably in recent

194                                                                                      SEF Species Summary 1999
years.
Mean unstandardised catch rates by seiners (based only on shots containing school whiting) are extremely
variable but were lower in 1996-98 than for the period 1986-94 upon which AFMA‘s catch rate
performance criterion is based. Standardised catch rates showed a similar pattern. Attempts to develop
targeting criteria were unsuccessful. This was supported by industry comments that in the depths (50-80m)
where the species co-occur they, industry, do not have clear targeting practices. A number of alternate
GLM models were considered but all gave similar results. The decline in catch rates in 1996-98 was also
accompanied by an increase in the mean depth fished from about 60-70m during 1986-1994 to 80m in
1998.
No school whiting were recorded as being discarded during 1998 but relatively small amounts (2.7%) were
discarded in previous years. The length frequency distributions of retained whiting are generally uni-modal
with fish ranging in length between 12 and 25 cm LCF but with most fish between 16 and 20 cm. The size
distributions were relatively stable from 1991 to 1998, although there are indications that, in 1991 and
1992, a greater proportion of larger fish were caught.
School whiting are short lived and grow rapidly. Parameters of the von Bertalanffy growth curve were
estimated to be:
         Linf = 23.91, K = 0.46, to = -0.46
School whiting in catches ranged in age from 1 to 8 years but most were 2 to 4 years of age. Between 1991
and 1998, the age composition of catches were relatively stable. Similarly to the size distributions there
appeared to be a slightly greater proportion of older fish in catches in 1991 ad 1992. One year old fish
were more numerous in 1995 catches than in the other years.
.The estimates of and uncertainty regarding recruitment and spawner biomass are sensitive to changing the
assessment method for including the catch-at-age data in the analysis. However, the qualitative results of
the assessment suggest relative (though uncertain) stability for the spawner biomass despite fairly high
exploitation rates on the older fish (Figure 2).




School Whiting                                                                                         195
                                       700

                                       600
           Relative spwaning biomass




                                       500

                                       400

                                       300

                                       200

                                       100

                                        0
                                             1991   1992   1993   1994   1995     1996        1997       1998
                                                                     Year




     Figure 2 Time-trajectory for relative spawner biomass and 90% probability intervals. Note: the results
     shown are for an Integrated Analysis.



     Uncertainties in assessment
     The first formal stock assessment of school whiting is particularly sensitive to the assumptions regarding
     model structure. This suggests that, at this time, only qualitative conclusions can be drawn. The model was
     fitted to data from 1991-98 only even though it is known data for earlier years do exist. There was
     insufficient time to conduct an extensive examination of sensitivity. However, the sensitivity to model
     structure is likely to dominate other aspects.
     There is still considerable uncertainty about interpreting trends in CPUE, particularly the recent declines in
     catch rates given interactions with flathead, market influences and environmental variability. However, by
     necessity, the assessment included standardised catch rates. Further work is required to develop better
     performance indicators as it is quite clear that catch rates are unlikely to be the most appropriate.

6.    IMPLICATIONS FOR MANAGEMENT
     The 1999 assessment is based on the first formal stock assessment of school whiting in the SEF. The
     assessment uses catch-at-age and fishing effort data.
     About 95% of the school whiting catch is taken by Danish seiners with Lakes Entrance the major port.
     Mean unstandardised catch rates by Danish seiners are extremely variable but were lower in 1996-98 than
     for the period 1986-94 upon which AFMA‘s catch rate performance criterion is based. Standardised CPUE
     showed a similar pattern. However, the implications of these data alone should be treated cautiously.
     Annual catches of whiting are influenced by several factors including market demand and the effort
     directed by the fleet at flathead. Catch statistics show that annual catches of whiting and flathead are
     inversely related and in recent years the effort in flathead depths has increased.
     Industry stressed that the decline seen in catches and catch rates did not reflect declining abundance but was
     due to market and environmental factors. In addition, they argued that the widespread prevalence of algae


     196                                                                         SEF Species Summary 1999
     in the region reduced their ability to fish for whiting and effected the quality of fish and their suitability for
     export. Fishermen noted that catches and catch rates in 1999 were higher than in recent years. It was
     further pointed out by Lakes Entrance fishermen that the size of the Danish seine fleet has reduced
     considerably since 1992 from over 20 to 15.
     Between 1991 and 1998 the size and age compositions of school whiting landings were relatively stable
     with no trends indicating decreasing abundance or increased fishing mortality. The estimates of and
     uncertainty regarding spawner biomass are sensitive to the method used for incorporating the catch-at-age
     data in the analysis. However, the qualitative results of the assessment suggest relative (though uncertain)
     stability for the spawner biomass.
     Despite the advance made in assessing school whiting this year, no attempt was made to conduct
     projections. The reasons for this were the uncertainty with which biomass could be estimated and the lack
     of a process for defining appropriate performance indicators. Extension of the assessment to include data
     from earlier years and a risk assessment based on projections of alternate TACs is recommended.

7.    RESEARCH NEEDS
     Basic data needs and collection
     High Priority
         Essential – data collection, through the ISMP
            Catch and effort (including analysis using GLM)
            Age- and size-composition of the landed catch
            Discards (magnitude and age- / size-composition)

     Further model development
     High Priority
      Extending the assessment to include catch-at-age data from the mid 1980s. This would bound the
       period of highest annual catches. The outcome of this assessment should be used to assist with the
       development of appropriate performance indicators.
      Undertaking a risk assessment based on projections of alternate TACs.
      Considering the results of the further analyses at a workshop in 2000.

     Specific research needs

     High Priority

      Investigation of means of reducing bycatch in Danish seine nets. Note: industry has applied to NHT for
       funding to commence this work.
      Correlation with environmental variability. Further studies may assist with interpreting trends in catch.

     Medium Priority
      Age validation.
      The effect of seasonal changes in diet and reproductive condition on the quality of fish should be
       investigated as an important factor influencing the marketing of the catch. A study of this type would
       be a useful subject for a post-graduate project.

     Generic (SEFAG-level) research needs
      Evaluating and designing fishery-independent surveys. An ARF-funded project has commenced but
        school whiting needs to be considered.
      SEFAG needs to consider a number of issues relating to Management Objectives and Performance
        Indicators. It is not clear that these are well understood as is the differences between risk assessment
        and harvest strategy evaluation.
      Assessments for blue grenadier, blue warehou and school whiting have all identified considerable
        errors/inconsistencies in SEF1 records. This issue needs to be addressed as a matter of some urgency.
                            2500
                                                                                                   actual TAC
           catch (tonnes)




                            2000                                                                   approved TAC
     School Whiting                                                                                                 197
                            1500


                            1000
Figure I Total annual verified trawl and Danish seine catches of school whiting calculated from the
        quota monitoring system (SEF2), and actual and approved total allowable catches (TAC)



                                     5
      standardised catch per shot




                                    4.5
                                     4
                                    3.5
                                     3
                                    2.5
                                     2
                                    1.5
                                     1
                                    0.5
                                     0
                                          90   91   92   93   94   95   96   97     98    99


Figure II Average annual standardised catch rates of eastern school whiting by Danish seine




198                                                                               SEF Species Summary 1999
School Whiting   199
200   SEF Species Summary 1999
SILVER TREVALLY

 1.   AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
      Objectives
      Ongoing
 1. To ensure that the silver trevally resource is utilised in a manner consistent with the principles of
    ecologically sustainable development.
    Immediate objective
 2. To maintain the productivity of the silver trevally stock:
       current jurisdictional boundaries and varying approaches to management by the States and
        Commonwealth need to be reconciled if this objective is to be achieved.
 3. To maximise the economic efficiency of the silver trevally fishery.
 4. To implement effective and efficient fisheries management on behalf of the Commonwealth.
      Strategies
      The above objectives will be achieved by:
 1. setting a TAC for the Commonwealth managed portion of the fishery that:
       maintains catch per unit effort (CPUE) above its lowest annual average level from 1986 to 1994
        [Notes: the TAC would currently only apply to the trawl sector of the fishery with the SEF,
        excluding the southern Remote Zone; non-SEF catches, which include recreational catches, are
        considerably greater than those from the SEF]
       consult with other interest groups regarding the level of the total catch
        (objectives 1 & 2)
 2. managing all sectors of the silver trevally fishery in a complementary manner
    (objectives 1 & 4)
 3. prioritising silver trevally research in relation to other SEF species:
       SETMAC has given a low research priority rating to this species
        (objectives 1, 2, 3 & 4)
 4. data collection
    (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing practices
          ensure accurate reporting of catch from all sectors of the fishery
      (ii) monitor length distributions in commercial catches
           (objectives 1 & 2)
 5. undertake economic research on the fishery to calculate GVP and monitor market prices for silver trevally
    (objective 3)
    Performance indicators
 1. That the current annual CPUE for the fishery is above its lowest annual average level from 1985 to 1994
    (strategy 1)
 2. That all sectors of the fishery are managed in a complementary manner
    (strategy 2)
 3. Data relevant to the annual assessment of silver trevally has been collected and analysed, and
    considered by SEFAG
    (strategies 1, 3, 4 & 5)
 4. The actual trawl catch relative to the trawl TAC
    (strategy 1)

 2.   STOCK STRUCTURE AND LIFE HISTORY
      Recent research indicates that silver trevally off south-eastern Australia represent a single stock that is
      distinct from the North Island of New Zealand. Growth rates are the same for both males and females
      and are slower than those reported for New Zealand. Larger sample sizes are required to confirm these


      Silver Trevally                                                                                               201
     results and further validation of the age estimates is proceeding using radiocarbon methods. The
     species ranges from north-east Queensland to north-western WA but little is known of the stock
     structure across Australian waters. Preliminary research suggests that the silver trevally off south-
     eastern Australia represent a single stock that is distinct from the North Island of New Zealand fishery.
     Whereas silver trevally growth rates are slower than those reported for New Zealand, the Australian
     stock matures comparatively early at about two years of age. Spawning occurs in early summer. The
     oldest Australian fish aged so far is less than half the age of the oldest New Zealand fish (47 years), but
     large fish (>60 cm) have yet to be sampled.

3.   THE FISHERY
     Current situation
     Annual SEF catches for the last decade have not exceeded the current TAC level of 500 t.
     The 1998 SEF2 total was 233 t (100 t Commonwealth, 133 t State), 37% less than 1997
     (372t). The catch from Commonwealth waters represented 16% of the actual TAC of 621 t
     and 20% of the agreed TAC of 500 t. The 1999 agreed TAC is 500 t, with an actual TAC
     of 601 t.

     Almost all (~90%) of the silver trevally catch is taken from Eastern Zone A, with the
     remainder predominantly from Eastern Zone B. Mean unstandardised catch rates (shots
     containing > 1kg of silver trevally) in Eastern Zone A are generally between 40 and 50
     kg/hr, although they did increase to around 60kg/hr in the late 1980s. Catch rates in
     Eastern Zone B are quite variable but have steadily declined in recent years to below
     10kg/hr. Although overall catch rates over recent years have remained relatively stable
     around 40kg/hr, in 1998 the mean unstandardised catch rates fell to 35kg/hr and triggered
     AFMA‘s catch rate performance criterion.

     The general view at the 1996 port meetings was that the stock was in good condition and
     abundant at present. Many operators commented that there was potential to increase
     catches and develop export markets. However, the interactions with other gear sectors
     (non-trawl, State, recreational) were acknowledged. There has been some development in
     gear and targeting of silver trevally. Because much of the SEF catch is genuinely taken
     from State waters and no State trip-limit applies to this species, the TAC does little to
     constrain the overall SEF catch. Significant catches are also taken north of the SEF
     boundary and by recreational fishers. Stock status remains unknown.

4.   PREVIOUS ASSESSMENTS
     The 1992 and 1993 assessments were based solely on catch and effort data. No CPUE
     trends were evident.
     Catch data and a few catch composition data were examined in the 1994 SEFAG meetings.
     Analysis of silver trevally CPUE using a generalised linear model (GLM) suggested that
     abundance rose from 1986 to 1990 but declined back to the 1986 level in 1992/93. It is
     unclear if an increase in the SEF catch from 195 t in 1992 to 459 t in 1993 was attributable
     to improved recording of catches from State waters, or changes in fish abundance,
     catchability, fishing practices, or a combination of these factors. Stock status was viewed as
     uncertain. Little is known about the resource, or the effects of fishing on it.



5.   1999 UPDATE
      There was no formal stock assessment of silver trevally undertaken in 1999.


     Catch and effort
     Annual SEF catches for the last decade have not exceeded the current TAC level of 500 t.
     The 1998 SEF2 total was 233 t (100 t Commonwealth, 133 t State), 37% less than 1997
     (372 t). Similar to previous years, most of the catch was from Eastern Sector A (87% by
     weight in 1998). Mean unstandardised annual catch rates (based only on shots containing


     202                                                                         SEF Species Summary 1999
     silver trevally) have remained comparatively stable in Eastern Sector A at between 40 and
     66 kg/hr from 1986 to 1998. The 1998 catch rate of 40 kg/hr was the lowest since 1986.
     Landings from Victorian endorsed vessels in 1997 (88 t) were 10% higher than landings in
     1996 (88 t). No landings were recorded for Tasmanian endorsed vessels.

     Size composition
     The size composition of silver trevally landings in Eastern Zone A have remained fairly
     consistent over recent years, ranging between 20 and 45 cm LCF with the bulk of the catch
     between 25 and 35 cm. Although sample numbers are not large, there is evidence of
     recruitment of a new cohort of fish of about 20 cm. The fisher are generally larger in
     Eastern Zone B, between 30 and 55cm. A cohort of smaller fisher was not apparent in
     these samples.

     Discarding
     As in previous years, there was virtually no discarding of silver trevally during 1998.

     Port visits
     No concerns over the status of the silver trevally stocks were expressed by industry at the
     port meetings. Generally, it was felt that trevally were in abundance and greater quantities
     were being caught because of improvements in net design rather than increased horsepower
     of vessels. The market value of this species is increasing and it is therefore becoming more
     important to operators.

     Prices
     In 1998, the gross value of recorded landings of silver trevally was estimated to be about
     $1.00 million. Average prices on both the Sydney and Melbourne fish markets were similar
     at around $1.60/kg. This is only slightly higher than the average price in the previous year
     ($1.50/kg).


6.   IMPLICATIONS FOR MANAGEMENT
     Silver trevally are a low priority species in the overall SEF quota context. Recent research
     indicating faster maturation, shorter life and slower growth compared with NZ stocks may
     indicate a stock more robust to fishing pressure. However, these initial findings require
     further sampling and confirmation. The current status of the stock is unknown.

     TACs currently do not constrain catches of this species, as a large proportion of the trawl
     catch is genuinely taken from State waters and no NSW trip-limit applies. Also, non-SEF
     catches are significant, both north of Barrenjoey and from the recreational fishery.

7.   RESEARCH NEEDS
     The SETMAC Research sub-committee accorded silver trevally a low research priority.
     Monitoring of SEFcatches and catch composition should continue. A research program
     currently under way by NSW FRI should assist in defining research needs for this fishery.




     Silver Trevally                                                                                203
                                700

                                600                                                                   actual TAC
         Total catch (tonnes)   500                                                                   approved TAC
                                400

                                300

                                200

                                100

                                 0
                                          1992    1993   1994    1995        1996        1997   1998
                                                                 Year


Figure I Total annual verified catches of silver trevally calculated from the quota monitoring system
        (SEF2), and actual and approved total allowable catches (TAC)



                                70

                                60
      av. catch rate (kg/hr)




                                50

                                40

                                30

                                20

                                10

                                0
                                     84      86    88    90     92      94          96     98   100


Figure II Avergae annual unstandardised catch rates of silver trevally




204                                                                                       SEF Species Summary 1999
Silver Trevally   205
206   SEF Species Summary 1999
SPOTTED WAREHOU

 1.    AFMA’S MANAGEMENT OBJECTIVES, STRATEGIES AND PERFORMANCE INDICATORS
    Objectives
    Ongoing
 1. To ensure that the spotted warehou resource is utilised in a manner consistent with the principles of
    ecologically sustainable development.

       Immediate objective
      2. To ensure that the spawning biomass of spotted warehou does not significantly decline below its
         current (1994) level:
                 current jurisdictional boundaries and varying approaches to management by the States and
                  Commonwealth need to be reconciled if this objective is to be achieved.
 3. To maximise the economic efficiency of the spotted warehou fishery.
 4. To implement effective and efficient fisheries management on behalf of the Commonwealth.

       Strategies
       The above objectives will be achieved by:
 1. setting a TAC for the Commonwealth managed portion of the fishery that:
              maintains catch per unit effort (CPUE) above its lowest annual average level from 1986 to 1994
           [Note: the TAC would currently only apply to the trawl sector of the fishery within the
           SEF, excluding the southern Remote Zone] (Objectives 1 & 2)
 2. managing all sectors of the spotted warehou fishery in a complementary manner
    (Objectives 1 & 4)
 3. prioritising spotted warehou research in relation to other SEF species:
    SETMAC has given a medium research priority rating to this species (Objectives 1, 2, 3 & 4)
 4. data collection
    (i) obtain estimates of catch, catch rates and monitor shifts in effort and changes in fishing practices
       (ii) monitor length distributions in commercial catches and undertake ageing as required
       (iii) obtain estimates of the spawning biomass of the fishery in 1994 as a baseline figure in the absence
             of being able to determine spawning biomass at the onset of significant commercial fishing,
             through catch-at-age analysis
                (Objectives 1 & 2)
 5. undertaking economic research on the fishery to calculate GVP and monitor market prices for spotted
    warehou (Objective 3)
    Performance indicators
 1. That the current annual CPUE for the fishery is above its lowest annual average level from 1986 to
    1994 (Strategy 1)
 2. That all sectors of the fishery are managed in a complementary manner (Strategy 2)
 3. Data relevant to the annual assessment of spotted warehou has been collected and analysed, and
    considered by SEFAG (Strategies 1, 3, 4 & 5)
 4. The actual trawl catch relative to the trawl TAC (Strategy 1)

 2.    STOCK STRUCTURE AND LIFE HISTORY
       Spotted warehou are found throughout south-eastern Australian waters (NSW, Victoria, Tasmania and
       South Australia). The species is also found in New Zealand waters and may occur off South America.
       Adults are caught in depths to about 650m. Spawning occurs during late winter/spring. Juveniles are
       pelagic, commonly associated with jellyfish. Sub-adults, although taken by trawlers, often occur in
       large embayments. Growth is relatively rapid with a maximum age of about 11 years. There have been



      Spotted Warehou                                                                                           207
     no studies on the stock structure of this species in Australian waters and, for assessment and
     management purposes, spotted warehou are currently assumed to be a single stock in the SEF.

     Spotted warehou are closely related to blue warehou and mixed catches do occur. This has led to
     confusion between the species in early catch statistics. This was most apparent in comparisons between
     logbook and ―verified‖ catch data. Also, early statistics were for the species combined, commonly
     recorded as ―Tassie trevally‖.

3.   THE FISHERY
     Current situation
     The 1998 SEF2 landed weight of spotted warehou was 2411 t (2410 t in Commonwealth
     waters and 1 t in State waters), which was 71% of the actual TAC of 3383 t. Overall,
     landed weight fell by about 374 t (14%) from 1997 to 1998. The non-trawl mesh sector
     landed xxx t in 1998. The 1998 agreed TAC was increased by 500 t and the 1999 agreed
     TAC is 4000 t, with an actual TAC of 4537 t.

     Spotted warehou are caught throughout the SEF, but catches in Bass Strait are negligible.
     Although variable, mean unstandardised catch rates (shots in which >1 kg of spotted
     warehou were caught) over recent years have tended to drop in the eastern zones, while
     catch rates to the west of Bass Strait have increased since the early 1990s. AFMA‘s catch
     rate performance criterion was triggered in 1996 and 1997. This was not the case in 1998,
     with catch rates increasing to above 130 kg/hr.

     Spotted warehou are a high volume species for which marketing plays an important role.
     The average return (net of marketing charges) received by trawl operators for spotted
     warehou in 1998 was estimated to be $XXX/kg. The gross value (net of marketing charges)
     of recorded SEF trawl landings of spotted warehou in 1998 was estimated to be about $XX
     million, 33 per cent higher than in 1997 due to rises in landings and prices. Catches by
     Commonwealth endorsed non trawl vessels were worth an estimated $XX million.

     Port meetings revealed that spotted warehou continue to be very abundant. However, the
     market cannot cope with big landings, which tended to restrain landings in 1996/97.
     Limited quota availability and high leasing prices also constrained catches in 1997. Large
     fish were much more abundant in 1996/97 catches. Industry believes that fluctuations in
     abundance are environmentally driven. Many operators noted the need to develop markets
     for this species and methods for processing and storing, although also noting that the
     current quota would be limiting if this occurred.

4.   PREVIOUS ASSESSMENTS
     Previous assessments of spotted warehou are limited but the fishery and biological
     characteristics have been described. In 1993, the assessment was limited to an examination
     of recent catch statistics and length data. Some data from the gill net fishery were also
     examined.

     The 1994 assessment considered catch and effort data, length frequency distributions and a
     yield per recruit analysis was undertaken. Catches of spotted warehou were variable,
     ranging from about 800 to 1650 t per annum. Between 1986 and 1993, the greatest catches
     of spotted warehou were taken in western Bass Strait (West) and Eastern Sector B. In
     Eastern Sector B and in the West, catches and catch rates were highest in winter and were
     variable. There were no trends in these data. Industry observations also suggest variable
     availability and/or abundance. Length frequency distributions for Lakes Entrance gill net
     vessels (1991-1993) were similar to those for blue warehou, with the dominant mode at
     about 50 cm LCF reflecting mesh selectivity. For trawl caught spotted warehou, length
     distributions were more variable. A significant component of the catch was juveniles (less
     than 40 cm LCF) but this was not as marked as for blue warehou. Data from Tasmania
     showed there was a marked relationship between size and depth for spotted warehou, with
     larger fish being taken in deeper water. Spotted warehou are also taken as a by-catch of



     208                                                                      SEF Species Summary 1999
     targeting blue warehou and, because this is usually in relatively shallow depths, the spotted
     warehou are generally juveniles.

     In the absence of fishing, the maximum cohort biomass occurs at ages 3 and 4 years. Yield
     per recruit was greatest for an age at first capture of 3 years.

5.   1999 UPDATE
     There was no formal assessment of spotted warehou undertaken during 1998/99. However,
     1998 logbook and ISMP data were incorporated into this summary.
     Catch and effort
     Landings of spotted warehou by Victorian and Tasmanian endorsed vessels have been
     predominantly from shark vessels, which since 1997, have been recorded in the new
     Commonwealth non-trawl logbook. The non-trawl landings of spotted warehou were 169 t
     in 1998, which is similar to that recorded in 1997. Mean unstandardised catch rates (based
     only on shots containing spotted warehou) have been extremely variable and little can be
     deduced from them. Nevertheless, the average 1997 and 1998 catch rates were 120 kg/hr,
     below the lowest annual average level from 1986 to 1994 and therefore triggering AFMA‘s
     CPUE performance criterion.
     Size composition
     The length frequency distribution of spotted warehou varied considerably in the different
     areas of the fishery. To the east of Bass Strait, a number of cohorts of fish were apparent in
     the catch, but their size ranges were not consistent in the different areas. To the west of
     Bass Strait, fish were generally larger, ranging from 40 to 55 cm LCF, with a mode around
     45 cm.
     Discarding
     During 1998, about 15% of the catch by weight was discarded across the fishery. This was
     similar to previous years, and discard levels were generally higher in the western zones than
     eastern zones. Similar to 1997, fish over the whole size range were discarded, especially in
     the western zones, suggesting that much of the discarding was market/quota driven. In
     previous years just the smaller fish were discarded.
     Based on the ISMP data, these discard rates equate to around 450 t of spotted warehou
     discarded across the SEF during 1998. Most of this (380 t) was in the western zones.
     Combined with the SEF2 landings of 2411 t, the total catch of spotted warehou (including
     discards) in 1998 was around 2860 t, which was 75% of the allocated TAC of 3833t.
     Port visits
     Comments from industry indicate that the species is very abundant and there was general
     consensus that the TAC could be increased, with many operators finding their quota
     holding restrictive. However, landings are often constrained by the market demand and
     glut periods had led to a considerable amount of discarding. This is exacerbated by the
     comparatively high lease price, as this species does not command a high market price.
     Operators were becoming adept at avoiding this species, when market demand was low.
     Eden operators noted that there had been a marked increase in the size of fish between
     1995 and 1997. It is believed that markets will improve as the fishery develops.

     During the 1999 port visits in the western zones, it was emphasised that availability of
     spotted warehou increased markedly in 1997 and 1998. There was concern that dumping
     would be a problem, especially during winter, as many operators will have caught there
     quota when prices were high during summer. It was noted that the fish were larger off
     Beachport compared to Portland.

     Prices
     In 1998, the gross value of recorded landings of spotted warehou was estimated to be about
     $2.28 million. Average prices were similar on the Sydney and Melbourne Fish Markets, at
     around$1.15/kg.




     Spotted Warehou                                                                                  209
6.   IMPLICATIONS FOR MANAGEMENT
     Spotted warehou were last assessed in 1994. The assessment concluded that there was no
     indication of an effect of fishing on spotted warehou, but the impact of the increase in the
     TAC from 2020 t in 1993 to 2603 t in 1994 was unknown. More recent examination of
     catch rates found them to be highly variable and of little use for assessment purposes. The
     status of this resource remains unknown.
     A significant proportion of juveniles is discarded and fishers would gain from taking the
     fish at a larger size.
     The market for this species appears to be developing, bringing increased pressure to raise
     the TAC. Whereas stock status is unknown, widespread catches and industry comment have
     indicated that this species is currently abundant in SEF waters. The 1998 TAC was
     consequently raised to a level 1000 t greater than the 1997 TAC. It is not known if catches
     can be sustained at the current TAC level of 3500 t as the current abundance is probably
     attributable to one or more above average cohorts passing through the fishery. Also, if the
     TAC is further increased, the implications of a possible increase in blue warehou by-catch
     should be considered, as the two warehou species commonly occur together.
     This species is being increasingly targeted by the non-trawl (mesh) sector. If this trend
     continues, consideration should be given to introducing a ‗global‘ TAC, as is now the case
     for blue warehou.
     Given the current high catch of this species (greater than historical levels), catch rates, size
     and age should be closely monitored. Because of the increasing importance of spotted
     warehou to the SEF, research on this species should be given a higher priority.

7.   RESEARCH NEEDS
     Spotted warehou have been accorded a medium priority by the SETMAC Research Sub-
     committee. However, as noted above, a high priority should now be given to this fishery.

     Research priorities are:
 To closely monitor age and length data from commercial catches from both the trawl and
  non-trawl sectors to provide the information required for more rigorous assessment,
  particularly age-structured models such as VPAs.
 To validate assigned ages to reduce uncertainty in productivity estimates. This should be
  undertaken as part of ‗routine‘ ageing.
 To formally analyse logbook data to examine the spatial dynamics of spotted warehou and
  provide the basis for a better understanding of annual variability in abundance and/or
  availability.
 To determine stock structure and size (if catches increase, this should be given a higher
  priority).




     210                                                                          SEF Species Summary 1999
                         3500

                         3000
                                                                             actual TAC
Total catch (tonnes)
                         2500
                                                                      approved TAC
                         2000

                         1500

                         1000

                                   500

                                               0
                                                        1992   1993   1994    1995        1996   1997   1998
                                                                              Year



   Figure I Total annual verified catches of spotted warehou calculated from the quota monitoring
           system (SEF2), and actual and approved total allowable catches (TAC)




                                               300

                                               250
                       av. catch rate(kg/hr)




                                               200

                                               150

                                               100

                                                   50

                                                   0
                                                        85 86 87 88 89 90 91 92 93 94 95 96 97 98 99



   Figure II Annual average unstandardised catch rates of spotted warehou




   Spotted Warehou                                                                                             211
212   SEF Species Summary 1999
Spotted Warehou   213

								
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