19 Western Deepwater Trawl Fishery

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					            chapter 19




19 Western Deepwater Trawl Fishery
            m rodgers, a Sampaklis and t Pham




F i g u r e 1 9 .1   Relative fishing intensity in the Western Deepwater Trawl Fishery, 2004–05 to 2008–09




                                                            chapter 19        Western Deepwater Trawl Fishery   337
t a B l e 1 9 .1              Status of the Western Deepwater Trawl Fishery

 Fishery status                                                      2008                                   2009                  Comments

  Biological status                               Overfishing             Overfished      Overfishing               Overfished
 Deepwater bugs                                                                                                                   Very low levels of fishing effort.
 (Ibacus spp.)                                                                                                                    No estimates of biomass.

 Orange roughy                                                                                                                    No targeting of orange roughy
 (Hoplostethus atlanticus)                                                                                                        (zero catch). No estimates of
                                                                                                                                  biomass.
 Ruby snapper                                                                                                                     Low levels of fishing effort. No
 (Etelis carbunculus)                                                                                                             estimates of biomass.

 Economic status                                  Estimates of net economic returns not available                                 Economic status uncertain. Total
 Fishery level                                                                                                                    net economic returns likely to be
                                                                                                                                  low given high level of latency,
                                                                                                                                  low catches and effort.

      n o t o verfi Shed / n o t Su b j e c t t o o v e r f i S h i n g            o v e r f i S h e d / overf iSh ing       uncerta in             not a SSeSSed




ta B l e 1 9 . 2              Main features and statistics of the Western Deepwater Trawl Fishery

 Feature                                                        Description
 Key target and byproduct species                               Deepwater bugs (Ibacus spp.)
                                                                Orange roughy (Hoplostethus atlanticus)
                                                                Ruby snapper (Etelis carbunculus)
 Other byproduct species                                        Bar rockcod (Epinephelus spp.)
                                                                Boarfish (Pentacerotidae)
                                                                Deepwater flathead (Neoplatycephalus conatus)
                                                                Mirror dory (Zenopsis nebulosus)
                                                                Tang’s snapper (Lipocheilus carnolabrum)
                                                                Other minor byproduct species are included in Table 19.4.
 Fishing methods                                                Demersal trawl
 Primary landing ports                                          Fremantle, Geraldton
 Management methods                                             Input controls: limited entry (11 permits) since 1998
 Management plan                                                Western Trawl Fisheries statement of management arrangements (AFMA 2004)
 Harvest strategy                                               Western Trawl Fisheries Harvest Strategy—North West Slope Trawl Fishery (NWSTF)
                                                                and Western Deepwater Trawl Fishery (WDTF) (AFMA 2007)
 Consultative forums                                            The Western Trawl Fisheries Management Advisory Committee was disbanded on
                                                                1 July 2009 and replaced by a small consultative panel tasked with focusing on key
                                                                strategic issues in the WDTF and North West Slope Trawl Fishery.
 Main markets                                                   Domestic: Perth, Sydney, Brisbane—frozen/chilled
                                                                International: United States, Spain, China, Japan—frozen
 EPBC Act assessments:
 —listed species (Part 13)                                      Current accreditation dated 28 September 2005
 —international movement of                                     Current accreditation (Wildlife Trade Operation) expires 15 November 2010
 wildlife specimens (Part 13A)
 Ecological risk assessment                                     Level 1: Scale Intensity Consequence Analysis (SICA) completed on 254 species
                                                                (Wayte et al. 2007)
                                                                Level 2: Productivity Susceptibility Analysis (PSA) completed on 129 species
                                                                (Wayte et al. 2007)
                                                                Level 3: Draft Sustainability Assessment for Fishing Effects (SAFE) completed on 103
                                                                species (Zhou et al. 2009)

                                                                                                                                   Table 19.2 continues over the page



338            Fishery status reports                      2009
ta B l e 1 9 . 2    Main features and statistics of the Western Deepwater Trawl Fishery         CONTINUED


 Feature                                    Description
 Bycatch workplans                          Western Deepwater Trawl Fishery Bycatch and Discarding Work Plan, 1 November
                                            2008–31 October 2010 (AFMA 2008b)
 Fishery statisticsa                                2007–2008 fishing season                     2008–2009 fishing season
 Fishing season                             1 July 2007–30 June 2008                     1 July 2008–30 June 2009
 TAC and catch by species:                  TAC              Catch (tonnes)              TAC             Catch (tonnes)
 —Deepwater bugs                            None             8.6                         None            <1
 —Orange roughy                             None             0                           None            0
 —Ruby snapper                              None             8.5                         None            28.0
 Effort                                     762 hours of trawling                        482 hours of trawling
 Fishing permits                            11                                           11
 Active vessels                             3                                            1
 Observer coverage                          Zero                                         Zero
 Real gross value of production             Confidential (<5 vessels)                    Confidential (<5 vessels)
 (2008–09 dollars)
 Allocated management costs                 $0.1 million                                 $0.1 million

EPBC Act = Environment Protection and Biodiversity Conservation Act 1999; TAC = total allowable catch; TAE = total allowable effort;
WDTF = Western Deepwater Trawl Fishery
a Fishery statistics are provided by fishing season unless otherwise indicated.




19.1        Background                                                      Catches in the WDTF were historically
                                                                        dominated by six main commercial
The Western Deepwater Trawl Fishery                                     finfish species or species groups: orange
(WDTF) operates in Western Australia                                    roughy (Hoplostethus atlanticus), oreos
between the western boundary of the Great                               (Oreosomatidae), boarfish (Pentacerotidae),
Australian Bight Trawl Sector in the south                              eteline snapper (Lutjanidae: Etelinae),
(115°08´E) and the western boundary of the                              apsiline snapper (Lutjanidae: Apsilinae)
North West Slope Trawl Fishery (NWSTF)                                  and sea bream (Lethrinidae). Between 2000
in the north (114°E) (Fig. 19.1). The WDTF is                           and 2005, deepwater bugs (Ibacus spp.)
predominantly an off-season diversification                             emerged as the most important target species,
for Northern Prawn Fishery vessels. The                                 although there has been a large reduction
fishery targets more than 50 species in                                 in effort (and consequently catch) over the
waters exceeding 200 m depth, in habitats                               past three years. Orange roughy has not been
ranging from temperate–subtropical in the                               targeted over the past six years. Most WDTF
south to tropical in the north (Table 19.2).                            target species are thought to be long lived
    The Western Trawl Fisheries statement                               and slow to mature. These characteristics
of management arrangements (2004) aligns                                warrant a precautionary approach to
fishing seasons with financial years, and                               management. The level of fishing and the
specifies a maximum of 11 fishing permits,                              extent of research activities are insufficient
each valid for five years (AFMA 2004).                                  to provide estimates of sustainable yields.
Different vessels may fish on the same permit,
provided only one vessel is fishing at any time.




                                                                    chapter 19        Western Deepwater Trawl Fishery             339
ta B l e 1 9 . 3    History of the Western Deepwater Trawl Fishery

 Year              Description
 1979              Exploratory fishing returned promising catches of big-spined boarfish.
 Mid-1980s         Exploratory fishing for scampi and prawns began.
 1987–88           102 vessels received endorsement to fish.
 1990–91           Endorsements reduced to 10 vessels.
 1994–95           Orange roughy catch peaked at 300 t.
 1997–98           Effort shifted to target shelf-break finfish resources, and ruby snapper emerged as dominant target finfish stock.


 1998              Limited entry of 11 fishing permits introduced.
 2001              Stock assessment of ruby snapper undertaken; model results inconclusive because data were limited.
 2002–03           Catch of deepwater bugs peaked at 160 t.
 2004              AFMA statement of management arrangements, in lieu of a management plan, came into effect.
 2005              CSIRO-managed research vessel undertook a mapping survey of benthic habitats on the continental shelf and
                   slope of south-west Australia.
 2006              An exploratory survey failed to detect target species in commercial quantities.
 2006–07           A joint AFMA–CSIRO ecological risk assessment undertaken.
 2008              Harvest strategy adopted by AFMA (January).
 2009              WestMAC disbanded and replaced by a consultative panel for Western Trawl Fisheries.

AFMA = Australian Fisheries Management Authority; CSIRO = Commonwealth Scientific and Industrial Research Organisation;
WestMAC = Western Trawl Fisheries Management Advisory Committee




19.2       h a r v e s t s t r at e g y                              assessment (ERA) process (the ERA results
                                                                     have not yet been published by the Australian
The Western Trawl Fisheries harvest strategy                         Fisheries Management Authority—AFMA).
(HS) (AFMA 2007), which applies to the                                   There are no reference points because of
NWSTF and the WDTF, reflects the mixed-                              the opportunistic nature and variable catch
species composition and opportunistic nature                         composition of the Western Trawl Fisheries.
of the two fisheries. The HS acknowledges                            In the absence of other information or
that there are no target reference points                            assessments, the triggers for target species
in terms of maximum economic yield                                   are based on the highest historical catch.
(MEY). It aims to strike a balance between                           Level 1 is half the highest historical catch,
precautionary management arrangements                                Level 2 is the highest historical catch, and
and allowing industry to capitalise on                               Level 3 is double the highest historical catch.
fishing opportunities, while emphasising                             Trigger levels and decision rules are applied
the need to collect biological data.                                 independently within two latitudinal zones
The HS prescribes species-specific threshold                         of the WDTF (north and south of 30°S).
levels for 14 key commercial stocks                                      The Level 1 trigger initiates an
(Table 19.4). Three catch trigger rules initiate                     investigation to reveal why the trigger has been
management actions that progressively                                reached. This is undertaken through analysis
increase data and analysis requirements on                           of logbooks and examination of standardised
the fisheries (Levels 1 and 2) and establish                         data on catch per unit effort. It may also
a limit reference point (Level 3). Separate                          result in expert consultation and a possible
triggers and control rules apply to vulnerable                       revision of limit reference points. The Level 2
species identified through the ecological risk                       trigger results in stock assessments, using


340        Fishery status reports      2009
biological parameters such as size-specific                         deepwater sharks. The HS also specifies
fishing mortality, natural mortality, growth and                    control rules for species identified as high
reproduction. A revision of trigger values is                       risk under the ERA framework. High-
also undertaken. Exceeding the Level 3 trigger                      risk teleosts and crustaceans have two
results in a cessation of fishing effort, pending                   trigger levels: an intermediate 2 t trigger
a stock assessment and expert consultation.                         (in effect initiating the same management
    The measures include a 50-animal move-                          responses as for the Level 1 trigger for target
on provision for high-risk chondrichthyans;                         species) and a 4 t catch limit (Level 2).
for the WDTF, these include a number of


ta B l e 1 9 . 4      Catch and trigger levels for key commercial species in the WDTF

                                                                hS Level 1          hS Level 2           hS Level 3
 Species                          Catch (tonnes)a            trigger (tonnes)    trigger (tonnes)     trigger (tonnes)
 Alfonsino                                     0                          20            30bc                 150
 (Beryx splendens)
 Bar rockcod                                   2                          10              20                   50
 (Epinephelus ergastularius,
 E. septemfasciatus)
 Boarfish                                      1                     250b               500b                1000
 (Pentacerotidae)
 Deepwater bugs                               60                      100               200                  400
 (Ibacus spp.)
 Deepwater flathead                           28                      200               500                 1000
 (Neoplatycephalus conatus)
 Deepwater prawns                              0                      100               200                  400
 (multiple species)
 Flame snapper                                 5                          50            100                  200
 (Etelis coruscans)
 Gemfish                                      <1                           5              10                   20
 (Rexea solandri)
 Mirror dory                                  <1                          10              25                   50
 (Zenopsis nebulosus)
 Orange roughy                                 6                          75            150                  300
 (Hoplostethus atlanticus)
 Ruby snapper                                 14                          25              50                 100
 (Etelis carbunculus)
 Scampi                                       <1                      100               200                  400
 (Metanephrops australiensis,
 M. boschmai, M. velutinus)
 Smooth oreodory                              <1                          2                4                      8
 (Pseudocyttus maculatus)
 Tang’s snapper                                2                          5               15                   20
 (Lipocheilus carnolabrum)

HS = harvest strategy
a Catch data from 2004–05 to 2007–08 pooled to maintain confidentiality
b In each of three consecutive years
c In each of five years from a 10-year period




                                                                chapter 19      Western Deepwater Trawl Fishery       341
                                                                                                      Figure 19.2 Catch: all species, WDW


19.3    the 2009 Fishery
        (2008–09 Fishing
                                                                                              Other
                                                                                              Bugs


        season)
                                                                                0.35




                                                    Catch (thousand tonnes)
                                                                                0.30


key target and byproduct species                                                0.25

                                                                                0.20
In the 2008–09 fishing season, a small number
                                                                                0.15
of operators were active in the WDTF, and
effort was variable across the fishery. The                                     0.10

catch was also small and diverse relative to the                                0.05

large fishing area. Effort in the WDTF from                                     0.00
2005–06 to 2006–07 was low (<300 trawl                                                  2000−01         2002−03    2004−05        2006−07        2008−09

hours) relative to historical levels, but there
                                                   Figure 19.2                                      Catch by financial year, 2000–01 to
was a noticeable increase in 2007–08, with         2008–09
correspondingly greater catches. However,
in 2008–09 effort decreased to 482 hours of                                                           Figure 19.3 GVP: all species, WDW

trawling (Table 19.2). The catch composition
included an array of finfish species. The                                                    Other
                                                                                             Bugs

majority of the catch was comprised of ruby                                              *   Confidential data


snapper (28 t), and there was a decrease                                        3.0
                                                     GVP (2008−09 A$ million)




in the catch of deepwater bugs (<1 t) from
                                                                                2.5
the previous fishing season (8.6 t).
    Value data for the fishery prior to                                         2.0

2000–01 are confidential because of the                                         1.5
small number of operators in the fishery
(less than five). From 2002–03 to 2004–05,                                      1.0

both volume and gross value of production                                       0.5
(GVP) for the fishery (Figs. 19.2 and 19.3)                                                                                  *      *       *      *
fell considerably. Until recently deepwater                                     0.0
                                                                                       2000−01        2002−03     2004−05        2006−07        2008−09
bugs have been the fishery’s most important
catch. The substantial reduction in catch also     Figure 19.3                                      Real GVP by financial year, 2000–01
                                                   to 2008–09
caused GVP to fall to less than $1.0 million
in real terms in 2004–05. The GVP of the
fishery from 2005–06 to 2008–09 are not
reported for confidentiality reasons. Catches      minor byproduct species
improved throughout 2007–08 and 2008–09            Byproduct species taken in the WDTF
but were still far below 2004–05 levels.           include bar rockcod (Epinephelus spp.),
                                                   boarfish (Pentacerotidae), deepwater flathead
                                                   (Neoplatycephalus conatus), mirror dory
                                                   (Zenopsis nebulosus), Tang’s snapper
                                                   (Lipocheilus carnolabrum) and snapper (Etelis
                                                   spp.) (Table 19.5). Given the opportunistic
                                                   nature of the WDTF, the list of species in
                                                   Table 19.5 is not exhaustive. As targeting
                                                   practices change, it is likely that other
                                                   species may be taken as byproduct. Catches
                                                   of Tang’s snapper should be monitored, as
                                                   this is considered a high-risk species under
Western Alliance   PHOTO: LO CKY M A RSH A LL
                                                   AFMA’s ERA process (AFMA 2008).

342     Fishery status reports   2009
ta B l e 1 9 . 5   Minor byproduct stocks—TACs/triggers, catches/landings and discards in the WDTF

                                                                                                                2004–05 to
                                                                                             2004–05 to         2008–09
                                                                    TaC/                     2008–09 catch      discards
  Species                                                           trigger                  (tonnes)           (tonnes)

 Deepwater flathead (Neoplatycephalus conatus)                      HS triggers                      32                        0
 Tang’s snapper (Lipocheilus carnolabrum)                           HS triggers                       8                        0
 Flame snapper (Etelis coruscans)                                   HS triggers                       5                        0
 Snapper, other (Etelis spp.)                                       None                              5                        0
 Bar rockcod (Epinephelus ergastularius, E. septemfasciatus)        HS triggers                       4                        0
 Amberjack (Seriola dumerili)                                       None                              3                        0
 Latchet (Pterygotrigla polyommata)                                 None                              3                        0
 Gould’s squid (Nototodarus gouldi)                                 None                              2                        0
 Mirror dory (Zenopsis nebulosus)                                   HS triggers                       2                   0.4
 Cuttlefish (Sepiidae)                                              None                              2                        0
 Northern pearl perch (Glaucosoma buergeri)                         None                              2                        0
 Boarfish (Pentacerotidae)                                          HS triggers                       2                   0.3
 Barracouta (Thyrsites atun)                                        None                              2                        0

HS = harvest strategy; TAC = total allowable catch; WDTF = Western Deepwater Trawl Fishery




19.4        B i o l o g i c a l s tat u s                          ta B l e 1 9 . 6     Biology of deepwater bugs


                                                                     Parameter           Description

deePWater bugS                                                       General             Deepwater bugs inhabit shallow, inshore
                                                                                         waters of the continental shelf and extend
(Ibacus spp.)                                                                            to the outer shelf and upper slope. They
                                                                                         form spawning aggregations, exhibit low
                                                                                         fecundity and are long lived, making
                                                                                         them susceptible to overfishing.
                                                                     Range               Species: In Australia, Ibacus spp. are
                                                                                         predominantly found in subtropical to
                                                                                         tropical regions, whereas Thenus spp. are
                                                                                         found in temperate waters.
                                                                                         Stock: The stock structure in the WDTF
                                                                                         is unclear. It is assumed to be a basket
                                                                                         stock for assessment purposes.
                                                                     Depth               30–400 m
                                                                     Longevity           >10 years
                                                                     Maturity (50%)      age: females 1.7–2 years post-settlement
                                                                                         Size: ~5–5.5 cm CL
                                                                     Spawning season June–December
                                                                     Size                Maximum: females 7 cm CL; males
                                                                                         7 cm CL
                                                                                         Recruitment into the fishery: not
                                                                                         determined

                                                                   CL = carapace length; WDTF = Western Deepwater Trawl Fishery
LINE DRAWINGS: FAO
                                                                   SO U RCE S : White & Sumpton (2002), Haddy et al. (2005).




                                                               chapter 19             Western Deepwater Trawl Fishery              343
                                              Figure 19.4 Catch: bugs, WDW


                                                                                              Future assessment needs
                                                                                              The low effort, low volumes of catch and
                                                                                              sporadic targeting of key commercial
                           0.16
                                                                                              species make it difficult to specify
 Catch (thousand tonnes)




                                                                                              research and assessment requirements
                           0.12
                                                                                              in the WDTF. Nonetheless, investigation
                                                                                              of spatial patterns of catch and effort
                           0.08                                                               for key commercial species is required.
                                                                                              Collection of basic biological information
                           0.04                                                               and spatial catch and effort information
                                                                                              for deepwater bugs will be required for
                           0.00                                                               future assessments, particularly if catches
                                  1993−94   1996−97   1999−00   2002−03   2005−06   2008−09
                                                                                              increase and/or fishing practices change.
Figure 19.4        Deepwater bug catch history by
financial year, 1992–93 to 2008–09
                                                                                              orange roughy
stock status determination                                                                    (Hoplostethus atlanticus)
No stock assessment exists for deepwater
bugs. A weight-of-evidence approach, using
catch and landing data since 1998–99 were
used to determine stock status. Fishing effort
and catches have been low over the past four
years (Fig. 19.4). Given the low volume of
catch in 2009, deepwater bugs are assessed
as not subject to overfishing (Table 19.1).                                                   LINE DRAWING: ROSALIND POOLE
However, as catches have been much higher in
the past and there are no estimates of biomass,                                               ta B l e 1 9 . 7   Biology of orange roughy
it is uncertain if the stock is overfished.
                                                                                               Parameter            Description
reliability of the assessment/s                                                                General              The stock structure of orange roughy in
                                                                                                                    the WDTF is unclear.
There is limited information with which
to assess stock status. Confidence that                                                        Range                Species: Occurs in all temperate oceans
                                                                                                                    except the north Pacific; in Australia, it
overfishing is not occurring is high, given                                                                         occurs across the south coast from
low catch and effort levels in 2008–09.                                                                             Sydney to Perth and is found in
                                                                                                                    continental slope and seamount areas.
                                                                                                                    Stock: The stock structure in the
previous assessment/s                                                                                               WDTF is unclear. It is assumed to be a
No previous stock assessments                                                                                       single stock within the area of the
                                                                                                                    fishery for assessment purposes.
have been undertaken.
                                                                                               Depth                180–1800 m, but usually found at
                                                                                                                    400–1000 m
                                                                                               Longevity            90–150 years
                                                                                               Maturity (50%)       age: 20–30 years
                                                                                                                    Size: ~25–30 cm SL
                                                                                               Spawning season      July–August
                                                                                               Size                 Maximum: 50–60 cm SL
                                                                                                                    Recruitment into the fishery:
                                                                                                                    24–42 years (size not available)

                                                                                              SL = standard length; WDTF = Western Deepwater Trawl Fishery
                                                                                              SOURCE : Gomon et al. (2008).
Trawl catch                           PHOTO: DAV I D GU I L LOT, A F M A




344                               Fishery status reports        2009
                                            Figure 19.5 Catch: orange roughy, WDW


                                                                                                 Future assessment needs
                                                                                                 Collection of basic biological information and
                           0.30
                                                                                                 spatial catch and effort data would be required
                                                                                                 to enable an assessment of the orange roughy
 Catch (thousand tonnes)




                           0.25                                                                  stock in the WDTF. As orange roughy is not
                           0.20
                                                                                                 currently being targeted this is unlikely to
                                                                                                 occur in the immediate future. Monitoring of
                           0.15
                                                                                                 its status is required should fishing resume.
                           0.10


                           0.05
                                                                                                 ruby SnaPPer
                           0.00
                                  1993−94    1996−97   1999−00   2002−03   2005−06   2008−09     (Etelis carbunculus)

F i g u r e 1 9 . 5 Orange roughy catch history by
financial year, 1992–93 to 2008–09


stock status determination
No model-based stock assessment exists
for orange roughy caught in the WDTF. A
weight-of-evidence approach, using catch                                                         LINE DRAWING: FAO

and landing data since the 1998–99 fishing
                                                                                                 ta B l e 1 9 . 8      Biology of ruby snapper
season were used to determine stock status.
There has been no targeting of orange roughy                                                      Parameter              Description
since 2005–06 (Fig. 19.5). As a result, the
WDTF orange roughy stock is assessed                                                              General                Ruby snapper is found over rocky
                                                                                                                         bottoms; however, little is known
as not subject to overfishing (Table 19.1).                                                                              about the biology of Australian stocks.
Its overfished status is uncertain as there                                                       Range                  Species: 21°15’S, 113°43’E –
are no current estimates of biomass, and                                                                                 26°24’S, 112°38’E; tropical waters
high levels of exploitation in the past create                                                                           from the Indo- and Central Pacific; in
                                                                                                                         Australia, from north-western Western
substantial uncertainty regarding biomass.                                                                               Australia to north-eastern Queensland
                                                                                                                         Stock: The stock structure in the
reliability of the assessment/s                                                                                          WDTF is unclear. It is assumed to be a
                                                                                                                         shared stock with Western Australian
There is limited information with which                                                                                  state fisheries for assessment purposes.
to assess stock status. Confidence that                                                           Depth                  90–400 m, limited to the shelf break
overfishing is not occurring is very high,                                                                               and extreme upper slope.
given the zero catch in 2008–09.                                                                  Longevity              25 years
                                                                                                  Maturity (50%)         age: ~3 years
previous assessment/s                                                                                                    Size: ~30 cm FL
No assessment has been made of orange                                                             Spawning season        3-month reproductive cycle over
roughy stocks in the WDTF. An exploratory                                                                                summer
fishing survey in 2006 searched suitable                                                          Size                   Maximum: in excess of 80 cm TL
habitats but failed to detect orange roughy.                                                                             Recruitment into the fishery: not
                                                                                                                         determined; optimal size for
Consequently, there is some concern about                                                                                harvesting is 63 cm TL
the biomass of orange roughy in the WDTF.
                                                                                                 FL = fork length; TL = total length; WDTF = Western Deepwater
                                                                                                 Trawl Fishery
                                                                                                 SOURCES : Grimes (1987); Hunter (2001); Martinez-Andrade
                                                                                                 (2003).




                                                                                               chapter 19           Western Deepwater Trawl Fishery           345
                                            Figure 19.6 Catch: ruby snapper, WDW


                                                                                               reliability of the assessment/s
                                                                                               There is limited information with which
                                                                                               to assess stock status. Confidence that
                           0.08
                                                                                               overfishing is not occurring is high, given
 Catch (thousand tonnes)




                           0.07
                                                                                               low catch and effort levels in 2008–09.
                           0.06

                           0.05                                                                previous assessment/s
                           0.04                                                                A stock assessment of ruby snapper was
                           0.03                                                                undertaken in 2001; however, model
                           0.02                                                                results were inconclusive because
                           0.01                                                                of data quality and quantity.
                           0.00
                                  1993−94    1996−97   1999−00   2002−03   2005−06   2008−09   Future assessment needs
F i g u r e 1 9 . 6 Ruby snapper catch history by financial
                                                                                               For ruby snapper, there is a need to
year, 1992–93 to 2008–09                                                                       collect biological data and improve
                                                                                               sample sizes of fisheries data for future
                                                                                               assessments, particularly if catches
stock status determination                                                                     increase and/or fishing practices change.
No model-based stock assessment took
place in 2009. Catch and landing data since
the 1998–99 fishing season were used to                                                        19.5     e c o n o m i c s tat u s
determine stock status (Fig. 19.6). Effort
has remained low, and the level of catch in
                                                                                               There have not been any economic surveys of
recent years has also been low, although in
                                                                                               the fishery. Effort and catches in the fishery
2008–09 catches increased slightly to a level
                                                                                               have been low over the past years. Given
similar to those in 2001–02 and 2002–03;
                                                                                               the low level of fishing effort and catch in
consequently, ruby snapper is assessed as
                                                                                               2007–08 and 2008–09, and the estimated high
not subject to overfishing (Table 19.1).
                                                                                               level of latency of permits, it is unlikely that
It is uncertain if the stock is overfished
                                                                                               profits in the fishery are significantly positive.
given previous levels of exploitation and
                                                                                               The low level of fishing effort in 2007–08
the lack of a reliable biomass estimate.
                                                                                               and 2008–09 has been attributed to high fuel
                                                                                               and operational costs (WestMAC 2008).



                                                                                               19.6     e n v i r o n m e n ta l
                                                                                                        s tat u s

                                                                                               The HS proposes the identification of spatial
                                                                                               closures to protect species and habitats
                                                                                               identified as high risk under AFMA’s ERA.
                                                                                               An existing area closure includes the Ningaloo
                                                                                               Marine Park (Commonwealth waters), which
                                                                                               extends as a narrow band from Point Murat
                                                                                               to south of Monck Head (Fig. 19.1). The
                                                                                               majority of the marine park is in state waters,
Trawl catch                           PHOTO: M I K E GER N ER , A F M A
                                                                                               except for a small part in the north that
                                                                                               encompasses the WDTF. The main objective
                                                                                               of the WDTF Bycatch and Discarding Work


346                               Fishery status reports         2009
Plan (AFMA 2008b) is to minimise overall            species of gulper shark—Harrisson’s
bycatch in the fishery over the long term.          dogfish (Centrophorus harrissoni), southern
                                                    dogfish (C. zeehaani, formerly C. uyato) and
ecological risk assessment                          endeavour dogfish (C. moluccensis)—have
                                                    since been nominated for threatened species
AFMA’s ERAs provided a list of high-risk            status under the Environment Protection and
species, based on their productivity (life          Biodiversity Conservation Act 1999, and a
history) and susceptibility to fishing effects.     decision is expected by 30 September 2010.
The ERAs considered target, byproduct and           Taxonomic studies have since determined
bycatch, including threatened, endangered           that west Australian stocks of gulper sharks
or protected (TEP) species. Based on the            do not include Harrisson’s dogfish, but rather
ERA process, no interactions with TEP               a new species, C. westraliensis (White et
species were detected. Twenty-two high-risk         al. 2008). The catch limit of 100 kg per day
species were identified; three of these are         for dogfish that previously applied in the
considered target species (gemfish, mirror dory     WDTF has been replaced by a 50-animal
and Tang’s snapper), and 19 are byproduct           move-on provision under the new Western
species (Wayte et al. 2007; AFMA 2008a).            Trawl Fisheries Harvest Strategy, although
Following the residual risk assessment, all         no minimum distance is specified.
high-risk species remained in the high-risk
category and have been incorporated into
the HS for the fishery (AFMA 2008a).
                                                    marine turtles and seabirds
                                                    No interactions with marine turtles or
habitats                                            seabirds have been reported in the WDTF.
Operators in the WDTF target catch using
demersal trawl gear. The impact of trawling
on benthic habitats has not been specifically       19.7    h a r v e s t s t r at e g y
investigated in the WDTF. However, trawling                 perFormance
is potentially destructive to seabed habitats.
Demersal trawling can have a significant            The WDTF is a mixed finfish and crustacean
impact on the sea floor by reducing structural      fishery. Most fishing effort has targeted
complexity of the environment, and crushing,        deepwater bugs and ruby snapper, with
burying or exposing marine organisms                sporadic targeting of deepwater flathead.
(Watling & Norse 1998). The recovery                Although the HS has been implemented,
potential of benthic assemblages is dependent       catch levels of the 14 key commercial
on the growth potential of structure-forming        finfish and crustacean species have not
organisms and the period of time between            exceeded the first trigger level, and so the
disturbances (Watling & Norse 1998). The            control rules have not been enacted.
areas most susceptible tend to be those that            In some instances, the trigger levels are
do not experience disturbance, such as shelf        inconsistent with the prescribed approach
and slope habitats and those that rely on slow-     in the HS. Level 2 triggers do not reflect
growing organisms for habitat complexity            high historical catches for alfonsino, bar
(e.g. coral reefs) (Watling & Norse 1998).          rockcod, boarfish, deepwater flathead, flame
                                                    snapper, mirror dory, scampi and ruby
Sharks                                              snapper. Additional information (such as
                                                    ERA results) was also used in setting triggers,
The strategic assessment of the WDTF                but this has not been applied consistently
recommended improved monitoring of                  across all species. Boarfish is a prime
catches of deepwater shark species, which
                                                    example—the highest historical catch of
are considered vulnerable to fishing because
                                                    boarfish in the WDTF was less than 5 t, but
of their life-history characteristics. Three
                                                    the Level 1 trigger for this species is 250 t;

                                                  chapter 19    Western Deepwater Trawl Fishery   347
as well, it is considered medium or high          concern is the reliability of Level 1 triggers,
risk (depending on the species of boarfish)       given that the HS may allow ongoing
under the ERA process (AFMA 2008a).               stock depletion (below the Level 1 trigger)
    Target species that were ranked as high       without enacting a management response.
risk under the ERA process are not subject to          A review of the HS is planned for
the prescribed intermediate and limit triggers    2010, using the Sustainability Assessment
detailed in the HS. In some cases, the triggers   for Fishing Effects (SAFE) methodology.
for these species are inconsistent with the       It is recommended that the review
historical high catch and do not appear to        considers the consistency of trigger
be precautionary. For example, both Tang’s        levels with high historical catch across all
snapper and mirror dory were rated as high-       species, as well as the reference period
risk species (AFMA 2008a), but neither is         used to determine trigger values.
subject to the prescribed intermediate or
limit triggers. Also, the Level 2 triggers are
greater than the highest historical catches.
                                                  19.8     l i t e r at u r e c i t e d
    There is no evidence that stocks are below
the default biomass proxy limit reference
point, although there is also no evidence that    AFMA (Australian Fisheries Management
the HS will ensure that stocks stay above           Authority) 2004, Western Trawl Fisheries
the limit biomass level at least 90% of the         statement of management arrangements,
time. A wide range of other species that are        AFMA, Canberra.
taken in the WDTF in small, yet consistent,       ——2007, Western Trawl Fisheries Harvest
quantities are not included in the HS.             Strategy—North West Slope Trawl Fishery
    It is too early to know whether the            (NWSTF) and Western Deepwater Trawl
HS will be effective in maintaining a              Fishery (WDTF), AFMA, Canberra.
sustainable fishery, as this will depend on       ——2008a Ecological risk management report
the level of future fishing effort. The WDTF       for the Western Deepwater Trawl Fishery,
also targets stocks that were exploited            August 2008, AFMA, Canberra.
considerably more in the early period of
the fishery, and it is possible that the HS       ——2008b, Western Deepwater Trawl Fishery
may not adequately protect stocks that are         Bycatch and Discarding Work Plan
subject to sustained fishing at low levels. Of     1 November 2008 – 31 October 2010,
                                                   AFMA, Canberra.
                                                  Gomon, M, Bray, D & Kuiter, R 2008, Fishes
                                                    of Australia’s south coast, New Holland
                                                    Publishers, Sydney.
                                                  Grimes, CB 1987, ‘Reproductive biology of
                                                     the Lutjanidae: a review’ in JJ Polovina & S
                                                     Ralston (eds), Tropical snappers and
                                                     groupers: biology and fisheries
                                                     management, Westview Press, Colorado,
                                                     pp. 239–94.
                                                  Haddy, JA, Courtney, AJ & Roy, DP 2005,
                                                     ‘Aspects of the reproductive biology and
                                                     growth of Balmain Bugs (Ibacus spp.)
                                                     (Scyllaridae)’, Journal of Crustacean
Bug   PHOTO: A BA R E – BRS
                                                     Biology, vol. 25, pp. 263–73.




348       Fishery status reports   2009
Hunter, C 2001, ‘Stock assessment of ruby
  snapper (Etelis carbunculus)’, Honours
  thesis, University of Queensland.
Martinez-Andrade, F 2003, ‘A comparison of
  life histories and ecological aspects among
  snappers (Pisces: Lutjanidae)’, PhD thesis,
  Louisiana State University.
Watling, L & Norse, EA 1998, ‘Disturbance of
  seabed by mobile fishing gear: a
  comparison to forest clearcutting’,
  Conservation Biology, vol. 12, no. 6, pp.
  1180–97.
                                                     Trawl catch   PHOTO DAV I D GU I LLOT, A F M A
Wayte, S, Dowdney, J, Williams, A, Fuller, M,
  Bulman, C, Sporcic, M, Smith, A, 2007,
  Ecological risk assessment for the effects
  of fishing: Report for the Western
  Deepwater Trawl Fishery, report for the
  AFMA, Canberra.
WestMAC (Western Trawl Fisheries
  Management Advisory Committee) 2008,
  Draft minutes from WestMAC 16,
  Freemantle, 14August 2008, <www.afma.
  gov.au/fisheries/northern_trawl/deepwater/
  mac/default.htm>.
White, E & Sumpton, W 2002, Assessment of
  the deep water line fishery in Queensland,
  Agency for Food and Fibre Sciences                 Trawl catch   PHOTO DAV I D GU I LLOT, A F M A

  project no. Q102081, final report to the
  Queensland Government, Department of
  Primary Industries, Brisbane.
White, WT, Ebert, DA & Compagno, LJV
  2008, ‘Description of two new species of
  gulper sharks, genus Centrophorus
  (Chondrichthyes: Squaliformes:
  Centrophoridae) from Australia’, in PR
  Last, WT White & JJ Pogonoski (eds),
  Descriptions of new Australian
  chondrichthyans, CSIRO Marine and
  Atmospheric Research paper no. 22, pp.
  1–21.
Zhou, S, Fuller, M & Smith, T 2009, Rapid            Trawl catch   PHOTO DAV I D GU I LLOT, A F M A
   quantitative risk assessment for fish species
   in additional seven Commonwealth
   fisheries, report to the AFMA, Canberra.




                                                   chapter 19      Western Deepwater Trawl Fishery    349

				
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