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18 Torres Strait Sea Cucumber and Trochus Fisheries

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									            chapter 18




18 Torres Strait Sea Cucumber and
   Trochus Fisheries
            j Woodhams and m rodgers




F i g u r e 1 8 .1   Area of the Torres Strait Sea Cucumber and Trochus Fisheries—Torres Strait Protected Zone (TSPZ)




                                           chapter 18         Torres Strait Sea Cucumber and Trochus Fisheries     321
t a B l e 1 8 .1             Status of the Torres Strait Sea Cucumber and Trocus Fisheries

  Fishery status                                                          2008                                  2009                   Comment
  Biological status                                  Overfishing             Overfished       Overfishing                Overfished
  Black teatfish                                                                                                                       Understood to be no domestic
  (Holothuria whitmaei)                                                                                                                fishery in 2009. Most recent
                                                                                                                                       survey estimates indicate a
                                                                                                                                       recovering stock.

  Prickly redfish                                                                                                                      Understood to be no domestic
  (Thelenota ananas)                                                                                                                   fishery in 2009. Relatively stable
                                                                                                                                       densities through recent history
                                                                                                                                       of fishery

  Sandfish                                                                                                                             Most recent published density
  (Holothuria scabra)                                                                                                                  well below pre-exploitation
                                                                                                                                       estimate. Confirmed illegal,
                                                                                                                                       unregulated or unreported
                                                                                                                                       harvest on Warrior Reef in early
                                                                                                                                       2009.

  Surf redfish                                                                                                                         Understood to be no domestic
  (Actinopyga mauritiana)                                                                                                              fishery in 2009. Density
                                                                                                                                       estimates are uncertain, and
                                                                                                                                       exploitation levels require
                                                                                                                                       further clarification.

  White teatfish                                                                                                                       Understood to be no domestic
  (Holothuria fuscogilva)                                                                                                              fishery in 2009. Relatively stable
                                                                                                                                       densities through recent history.

  Other sea cucumber species                                                                                                           Understood to be no domestic
  (18 species)                                                                                                                         fishery in 2009. Catch
                                                                                                                                       composition difficult to discern.
                                                                                                                                       Number of species inhibits
                                                                                                                                       certainty.

  Trochus                                                                                                                              Reported take in 2009 below
  (Trochus niloticus)                                                                                                                  historic levels and plausible
                                                                                                                                       sustainable extraction rates.
                                                                                                                                       Uncertainty in survey results.

  Economic status                                    Estimates of net economic returns not available                                   n.a.
  Fishery level

n.a. = not available
      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 8 . 2             Main features and statistics of the Torres Strait Sea Cucumber and Trochus Fisheries

  Feature                                             Description

  Key target and byproduct                            Black teatfish (Holothuria whitmaei)
  species                                             Prickly redfish (Thelenota ananas)
                                                      Sandfish (Holothuria scabra)
                                                      Surf redfish (Actinopyga mauritiana)
                                                      White teatfish (Holothuria fuscogilva)
                                                      Other sea cucumbers (up to 18 other species)
                                                      Trochus (Trochus niloticus)
  Other byproduct species                             Nil
  Fishing methods                                     Hand collection: free-dive, reef walking; breathing apparatus permitted when fishing for
                                                      trochus
  Primary landing ports                               Island processors

                                                                                                                                       Table 18.2 continues over the page



322            Fishery status reports                      2009
ta B l e 1 8 . 2       Main features and statistics of the Torres Strait Sea Cucumber and Trochus Fisheries           CONTINUED


  Feature                              Description

  Management methods:                  Sea cucumber:
                                       —Input controls: limited entry, gear restrictions
                                       —Output controls: competitive TAC, size limits
                                       Trochus:
                                       —Input controls: limited entry, gear restrictions
                                       —Output controls: competitive TAC, size limits
  Management plan                      No formal plans of management
  Harvest strategy                     No formal harvest strategies
  Consultative forums                  Torres Strait Fisheries Management Advisory Committee (TSFMAC), Torres Strait Scientific
                                       Advisory Committee (TSSAC), Torres Strait Hand Collectables Working Group (TSHCWG)
  Main markets:                        Sea cucumber:
                                       —International: China—predominately as a dried product, small amounts frozen or salted
                                       —Domestic: minimal
                                       Trochus:
                                       —International: Historically, markets have included France, Germany, Italy, Spain, Japan,
                                       United Kingdom, United States, Thailand, Philippines and China.
                                       —Domestic: minimal
  EPBC Act assessments:
  Sea Cucumber Fishery:
  —listed species (Part 13)            Current accreditation dated 10 June 2008
  —international movement of           Current accreditation (Wildlife Trade Operation) expires 20 June 2011
  wildlife specimens (Part 13A)
  Trochus Fishery:
  —listed species (Part 13)            Current accreditation dated 8 November 2008
  —international movement of           Current accreditation (Wildlife Trade Operation) expires 25 November 2011
  wildlife specimens (Part 13A)
  Ecological risk assessment           None
  Bycatch workplans                    None

  Fishery statistics    a
                                                   2008 fishing season                                 2009 fishing season

  Fishing season                       Calendar year                                       Calendar year
  TAC and catch by species:            TAC (tonnes)       Catch (tonnes)                   TAC (tonnes)       Catch (tonnes)

  —sandfish                            Zero               n.a                              Zero               None reported (IUU)
  —black teatfish                      Zero               n.a                              Zero               Zero
  —surf redfish                        Zero               n.a                              Zero               Zero
  —prickly redfish                     20                 n.a                              20                 Zero
  —white teatfish                      15                 n.a                              15                 Zero
  —other sea cucumbers                 80                 n.a                              80                 Zero
  (combined)
  —trochus                             150                8                                150                1.5
  Effort                               Sea cucumber: no reported effort in 2008            Sea cucumber: no reported effort in 2009
                                       Trochus: 16 sellers                                 Trochus: 7 sellers
  Fishing licences                     Sea cucumber: 76                                    Sea cucumber: 49
                                       Trochus: 110                                        Trochus: 110
  Active vessels                       Sea cucumber: 0                                     Sea cucumber: 0
                                       Trochus: 16                                         Trochus: 7
  Observer coverage                    Zero                                                Zero
  Real gross value of                  2007–08: not available                              2008–09: not available
  production (2008–09 dollars)
  Allocated management costs           n.a.                                                n.a.

EPBC Act = Environment Protection and Biodiversity Conservation Act 1999; TAC = total allowable catch; n.a. = not available;
IUU = Illegal, unreported and unregulated (fishing)
a Fishery statistics are provided by fishing season unless otherwise indicated.
S OU R C E S :   Raudzens (2007); Skewes et al. (2010).


                                                  chapter 18           Torres Strait Sea Cucumber and Trochus Fisheries               323
18.1    Background                                   their fishing operations for sea cucumbers.
                                                     After harvesting, the sea cucumber goes
                                                     through a number of processing stages,
Sea cucumber fishery                                 typically reaching the market as the gutted,
Fishing for sea cucumbers in the Torres              boiled and dried product, bêche-de-mer.
Strait is a highly selective fishing activity,           Sandfish have traditionally been a primary
conducted either through reef-top walking            target species in the Torres Strait, with the
or free-diving from dinghies (Table 18.2).           majority of fishing for this species taking
Twenty-three species of sea cucumber                 place on the Warrior Reef complex (Fig. 18.1).
have been recorded in the Torres Strait.             Fishing pressure led to a marked decline
They are of variable commercial value,               in the stock, resulting in the introduction
and not all are targeted by fishers for              of a zero total allowable catch (TAC) for
commercial purposes (Skewes et al. 2010).            the species in 1998 (Table 18.3). Fishers
    Participation in the Sea Cucumber                then switched to targeting black teatfish
Fishery is largely limited to the Torres Strait      and what is now understood to be a suite of
Traditional Inhabitants, with the exception          redfish and blackfish species (Actinopyga
of one long-term, non-traditional licence            spp.), previously reported as surf redfish.
holder who was active in the fishery before          The TACs for black teatfish and surf redfish
the introduction of limited entry in April           were set to zero in 2003 (Table 18.3). As a
1999. Traditional fishers who wish to harvest        result of zero TACs for these higher value
sea cucumber commercially are required               species, fishing activity is understood to
to hold a Traditional Inhabitant Boat (TIB)          have been relatively low in recent years.
licence. Fishers are not permitted to use
breathing apparatus (hookah or scuba) in             trochus fishery
                                                     The fishery for trochus in the Torres Strait
                                                     is a small, single-species commercial
                                                     fishery. Participation in the fishery is
                                                     restricted to Traditional Inhabitants, for
                                                     some of whom it can be an important source
                                                     of income. The shell is used mainly for
                                                     buttons, jewellery and fashion accessories,
                                                     while the byproduct (trochus meat) may
                                                     be consumed. Current participation in the
                                                     fishery is understood to be relatively low,
                                                     largely as a result of the low price paid for
                                                     product (Murphy et al. 2009). A minimum
                                                     (80 mm) and maximum (125 mm) size limit
                                                     (basal diameter) applies to commercial
                                                     fishing. The TAC for 2009 was 150 t.
                                                         Trochus are typically found on high-energy
                                                     areas of reefs, on substrates dominated by
                                                     stony or coral pavements, associated with
                                                     turf algae. They are not typically found in
                                                     environments with high concentrations of
                                                     sand and/or mud (Murphy et al. 2009).


Sea cucumber research    PHOTO: P. SEDE N, A F M A




324     Fishery status reports   2009
ta B l e 1 8 . 3     History of the Torres Strait Sea Cucumber and Trochus Fisheries

 Year                 Description

 1700s                Macassans from south-west corner of Sulawesi (formally South Celebes) fished northern Australia.
 1839                 Presence of traders and processing facilities in the Northern Territory.
 1912                 Commercial collection of trochus in Australia began, with the shell exported to Japan, United
                      Kingdom and Europe, primarily for use in making buttons and jewellery. The Australian trochus
                      fishery continued until about 1950, when plastics were developed for button production.
 1916 to 1917         124 vessels registered solely for the collection of sea cucumber; 558 t (dry weight) exported from
                      Thursday Island, although the exact source of this catch is unknown.
 1917 to 1939         Continual fishery expansion until 1928. By World War II, the fishery had contracted significantly.
 1977 to 1980         Over this entire period, 6 t of sea cucumber was reportedly exported, primarily from PNG.
 1984–85              1.7 t of sea cucumber harvested.
 1990 to 1993         The PNG catch between 1990 and 1993 reportedly ranged between 109 t and 192 t of processed
                      beche-de-mer (nearly all sandfish)—equivalent to approximately 1160 t and 2040 t of gutted weight
                      (Skewes et al. 2006). There was a brief resurgence in the trochus fishery in the 1990s for use in
                      ceramics.
 1993                 Fishing on the PNG side of Warrior Reef for sandfish was closed as a result of concerns about
                      overfishing. The closure remained in effect until 1995, when the fishery was reopened under a
                      management plan, including an annual 40 t (dry weight) TAC.
 1994 to 1996         Resurgence of the Sea Cucumber Fishery in the Australian area of the TSPZ; catch in 1995 estimated
                      between 1200 t and 1400 t (wet weight), with all but about 50 t being sandfish. Competitive TACs of
                      260 t per species (wet weight) for sandfish, black teatfish, white teatfish and prickly redfish and a
                      collective quota of 80 t for the remainder of species were implemented in 1995, along with minimum
                      size limits.
 1998                 Zero TAC introduced for sandfish in the TSPZ.
 1999                 Management responsibilities for the Torres Strait fisheries transferred from the (then) Queensland
                      Fisheries Management Authority to the Torres Strait Protected Zone Joint Authority.
 2003                 Zero TAC introduced for black teatfish and surf redfish in the TSPZ. Reduction in TAC for white
                      teatfish and prickly redfish to 15 t and 20 t, respectively.
 2005                 Recent trochus catches peaked at 96 t.
 2009                 PNG Sea Cucumber Fishery closed for three years from 1 October 2009. Survey of sea cucumbers
                      and trochus in eastern Torres Strait indicated recovery of the black teatfish population (Skewes et al.
                      2010).
PNG = Papua New Guinea; TAC = total allowable catch; TSPZ = Torres Strait Protected Zone
S OU R C E S : Conand and Byrne (1993); Stutterd & Williams (2003); Skewes et al. (2004, 2006).




18.2        h a r v e s t s t r at e g y                               has asked its management forums to provide
                                                                       advice on the application of the HSP to
The Commonwealth Fisheries Harvest                                     Torres Strait fisheries, there are currently
Strategy Policy (HSP) (DAFF 2007) is not                               no formal harvest strategies for the Torres
                                                                       Strait Sea Cucumber and Trochus Fisheries.
prescribed for fisheries jointly managed by the
                                                                           A number of communities have
Australian Government and other management                             expressed interest in developing
agencies (domestic or international), including                        community-based management plans for
the fisheries of the Torres Strait. Although the                       hand collection fisheries, and a number
Torres Strait Protected Zone Joint Authority                           may be in the process of doing so.



                                                chapter 18            Torres Strait Sea Cucumber and Trochus Fisheries     325
18.3    the 2009 Fishery                           black teatfiSh
                                                   (Holothuria whitmaei)
Sea cucumber fishery
There was no fishing for sea cucumbers
by Traditional Inhabitants (or the one
non-traditional license holder) in 2009.
This has been confirmed by staff of the
Australian Fisheries Management Authority          LINE DRAWING: FAO

(AFMA) and the Queensland Boating                  ta B l e 1 8 . 4      Biology of black teatfish
and Fisheries Patrol. Skewes et al. (2010)
also indicate that the Sea Cucumber                 Parameter                Description
Fishery was inactive in 2009, informed by
                                                    General                  Medium to large sea cucumber that
conversations with Islander processors.                                      typically inhabits shallower reef-flat
    In early 2009, a number of apprehensions                                 and reef-edge habitats. May be found
                                                                             associated with seagrass habitats.
were made of Papua New Guinea (PNG)
nationals fishing illegally for sea cucumbers on    Range                    Species: Likely to have a broad
                                                                             distribution throughout the fishery,
the Warrior Reef complex. With the closure of                                particularly in the east Torres Strait
the PNG Sea Cucumber Fishery on 1 October                                    Stock: The area of the Torres Strait
2009, the incidence of PNG nationals fishing                                 Protected Zone

illegally in the Australian area of the Torres      Depth                    Relatively shallow range, down to
                                                                             ~20 m
Stratit Protected Zone (TSPZ) is understood
to have ceased (AFMA pers. com.).                   Longevity                Not known. White teatfish, a similar
                                                                             species, has been estimated at 12+
                                                                             years.
trochus fishery                                     Maturity (50%)           age: Not determined
                                                                             Size: 800 g; 260 mm TL
The Torres Strait Trochus Fishery in 2009
                                                    Spawning season          Cooler months of the year (June–
experienced low effort, with a reported                                      August)
harvest of approximately 1.5 t (Table 18.2).
                                                    Size                     Maximum: 560 mm TL; 4.3 kg
The stock was surveyed in early 2009.                                        whole weight
                                                                             Recruitment into the fishery:
                                                                             minimum size limit 250 mm TL

                                                   TL = total length
18.4    B i o l o g i c a l s tat u s
                                                   NOTE: Statistics presented in this and other biology tables for
                                                   sea cumbers may not necessarily have been from research on
Status determination of a number of stocks in      Australian stocks.
the Torres Strait Sea Cucumber and Trochus         SO U RCE S :   Conand (1989, 1998); Kinch (2008); www.pzja.
Fisheries has been undertaken using a weight-      gov.au.
of-evidence approach. In the absence of
resource-intensive, fully quantitative stock       stock status determination
assessment models, a process for determining       The most recent survey of sea cucumbers
biological status has been formed through          in the Torres Strait was undertaken in 2009
the accumulation of all available quantitative     (Skewes et al. 2010). Preliminary results
and qualitative evidence. This approach            from the 2009 survey indicate a substantial
has been particularly important for white          increase in the mean density of black teatfish
teatfish and prickly redfish in 2009.              from the survey in 2005. Results also indicate
                                                   increases in mean length and mean weight
                                                   of black teatfish. It is important to note,
                                                   however, that all these estimates come with
                                                   considerable uncertainty around the mean
                                                   estimates. Skewes et al. (2010) recommend


326     Fishery status reports   2009
reopening the fishery for black teatfish, with      previous assessment/s
a TAC of 25 t. This amounts to an extraction        Prior to the 2009 survey (Skewes et al.
rate of about 4% of the lower 90th percentile       2010), the next most recent assessment of
of the standing stock estimate of 624.5 t.          Torres Strait sea cucumbers was published
    Black teatfish is assessed as not               in 2006 (Skewes et al. 2006), based on
overfished, based on the data presented in the      survey data collected in 2005. This survey
latest survey report (Skewes et al. 2010). These    found that black teatfish were less abundant
data appear to show a substantial recovery of       than in 2002. The assessment recommended
the stock since closure of the fishery in 2003.     maintaining the zero TAC for this species.
    Although reporting of catch of sea                  In 2002 surveys of the eastern Torres
cucumbers by TIB fishers in the Torres              Strait and the Warrior Reef complex were
Strait is not mandatory, it is understood           conducted (Skewes et al. 2004). The
that there has been no domestic fishery for         surveys of the eastern Torres Strait aimed to
sea cucumbers in the Torres Strait in 2009.         estimate abundance, length and weight of
On this basis, black teatfish is assessed as        all commercial sea cucumbers. Outputs of
not subject to overfishing (Table 18.1).            this work included estimation of the level
    The Torres Strait Sea Cucumber Fishery          of exploitation of each species, biomass
is understood to have been inactive in recent       estimates, estimates of maximum sustainable
years. Issuing of a TAC for a high-value            yield (MSY) and a TACs for each species.
species such as black teatfish is likely to             Black teatfish and surf redfish were
have a stimulating effect on the fishery.           considered overexploited, resulting in the
Mechanisms to effectively monitor catch             recommendation of zero TAC for these species
and stop the harvesting of stocks when              (implemented in 2003). Other species, such as
TACs have been reached will be important            white teatfish and prickly redfish, were thought
for long-term sustainability of this fishery.       to have historically been subject to harvesting,
The fishery should also consider scheduling         but their populations did not appear to have
further surveys of sea cucumber stocks to           been severely depleted. TACs for white teatfish
detect the stock response to harvesting.            and prickly redfish were estimated at 15 t and
                                                    20 t, respectively. Several other species were
reliability of the assessment/s
                                                    found to have relatively large standing stocks.
The TAC estimate from the latest
assessment can be considered reasonable
and conservative (Skewes et a. 2010).
Uthicke et al. (2003) indicate that a harvest
rate of less than 5% of the virgin biomass
estimate for black teatfish on the Great
Barrier Reef would be appropriate.
    The abundance estimates derived from
the surveys undertaken in 2002, 2005 and
2009 can be considered reliable, given the
established and repeated methodology. A
survey conducted in 1995 concluded that
there were substantial populations of a
number of species of sea cucumber in the
east of the Torres Strait, but that further
survey work was required to reliably
estimate abundance (Long et al. 1996).              Sea cucumber    PHOTO: M I K E GER N ER , A F M A




                                   chapter 18      Torres Strait Sea Cucumber and Trochus Fisheries     327
Future assessment needs                                            1.42 individuals/ha to 2.15 individuals/ha,
Future assessment needs are the same as for                        increasing from 1.44/ha to 1.99/ha from 2005
sandfish.                                                          to 2009. The mean weight of prickly redfish
                                                                   has also been relatively stable over the period
                                                                   2002 to 2009, at 2652 g (2002), 2147 g
Prickly redfiSh                                                    (2005) and 2812 g (2009), also increasing
                                                                   from 2005 to 2009. Although these means
(Thelonota ananas)                                                 are accompanied by considerable uncertainty
                                                                   around the mean estimate, the estimation
                                                                   methodology can be considered sound. The
                                                                   stability in density estimates and increases
                                                                   in size and weight indicate that the stock is
                                                                   probably not being significantly impacted by
LINE DRAWING: FAO                                                  fishing at current levels and is the basis for
                                                                   the not overfished status determination.
ta B l e 1 8 . 5         Biology of prickly redfish                    After the 2002 survey of eastern Torres
                                                                   Strait, Skewes et al. (2004) classified prickly
  Parameter                 Description
                                                                   redfish as ‘exploited’ and proposed a TAC of
  General                   A relatively large sea cucumber,       20 t. Whilst the ABARE–BRS has been unable
                            typically found on harder, broken
                            coral or rubble-based substrates on
                                                                   to clarify the comparative and qualitative
                            the reef edge/slope.                   nature of this ‘exploitation’ assessment
  Range                     Species: Likely to have a broad        process, the status and the fact that a TAC
                            distribution throughout the fishery,   was proposed for this stock may act as
                            particularly in the east
                            Stock: The area of the Torres Strait
                                                                   another line of evidence to support the 2009
                            Protected Zone.                        classification. Additionally the 20 t TAC was
  Depth                     Down to ~25 m                          calculated using the lower 90% confidence
                                                                   interval of the biomass estimate (342.5 t),
  Longevity                 Not known
                                                                   amounting to a conservative approach.
  Maturity (50%)            age: not determined
                            Size: 1230 g; 300 mm TL
                                                                       Although reporting of catch of sea
                                                                   cucumbers in the Torres Strait is not
  Spawning season           Warmer months of the year
                            (November–February)                    mandatory, it is understood that there was
                                                                   no domestic fishery for sea cucumbers
  Size                      Maximum: 980 mm; 8 kg whole
                            weight                                 in the Torres Strait in 2009. On this
                            Recruitment into the fishery:          basis, prickly redfish is assessed as not
                            minimum size limit 300 mm TL
                                                                   subject to overfishing (Table 18.1).
TL = total length
S O UR C E S :   Conand (1989, 1998); Kinch (2008); www.pzja.      reliability of the assessment/s
gov.au.
                                                                   Reliability of the assessments is the same as
stock status determination                                         for white teatfish.
In 2009 prickly redfish is assessed as not                         previous assessment/s
overfished and not subject to overfishing                          The same as for white teatfish.
(Table 18.1). This is based on preliminary
results from the 2009 survey (Skewes et al.                        Future assessment needs
2010), which presents re-estimated values for                      Future assessment needs are
density, length and weight of sea cucumbers                        the same as for sandfish.
for the four surveys undertaken between 1995
and 2009 in eastern Torres Strait. The mean
density of prickly redfish has been relatively
stable over the period 1995 to 2009, at between


328              Fishery status reports   2009
SandfiSh                                                               2006 assessment and the data in previous
(Holothuria scabra)                                                    assessments in 2002, 2000, 1998 and 1995.
                                                                           A back-calculation of the density required
                                                                       to support the 1995 catch of sandfish is
                                                                       presented in the 2006 assessment. This
                                                                       estimated the density of sandfish in 1992
                                                                       to be around 1600 individuals per hectare.
                                                                       The mean estimate from the 2004 survey
LINE DRAWING: FAO                                                      in the Torres Strait was 88 (standard error
                                                                       of 21) individuals per hectare. This would
ta B l e 1 8 . 6        Biology of sandfish                            indicate a substantially depleted stock.
  Parameter                 Description
                                                                           The sandfish fishery in Australian waters
                                                                       has been closed since 1998. However, the
  General                   Small to medium-sized sea cucumber,
                            typically found on inner reef flats and    ABARE–BRS has confirmed that a number
                            lagoons. Often associated with             of apprehensions were made of PNG nationals
                            seagrass habitats.
                                                                       for sea cucumber related offences on the
  Range                     Species: In the Torres Strait, sandfish    Warrior Reef complex over the past couple
                            is understood to be largely restricted
                            to the Warrior Reef complex and            of years, including some in early 2009.
                            likely to be a shared stock with PNG.          Although the HSP is not prescribed for
                            Stock: The area of the Torres Strait
                            Protected Zone.
                                                                       fisheries jointly managed by the Australian
                                                                       Government and other management
  Depth                     Relatively shallow: <10 m
                                                                       agencies, in the absence of an established
  Longevity                 6+ years                                   harvest strategy, the HSP was used
  Maturity (50%)            age: 2 years                               by ABARE–BRS to inform the status
                            Size: 184 g; 160 mm TL
                                                                       determination process for these stocks.
  Spawning season           Warmer months of the year
                                                                           The directive from the HSP is that:
  Size                      Maximum recorded: 350 mm TL;
                            1 kg whole weight                              Any fishing mortality will be defined
                            Recruitment into the fishery:                  as overfishing if the stock is below
                            minimum size limit 180 mm TL
                                                                           BLIM , unless the fishing mortality is
TL = total length                                                          below the level that will allow the
S OU R C E S :   Conand (1989, 1998); Kinch (2008); www.pzja.              stock to recover within a period
gov.au.
                                                                           of 10 years plus one generation
stock status determination                                                 time, or three times the mean
                                                                           generation time, which ever is less.
The most recent survey of sandfish was
undertaken in early 2010, but the results                              As ABARE–BRS has confirmation of
of this survey were not available at the                               targeted illegal fishing of this overfished
time of publication. As a result, the 2009                             stock in early 2009, and there is evidence
status determination is based on the 2006                              from surveys (since 1998) that the stock
assessment of sandfish in the Torres Strait                            is not rebuilding, sandfish is assessed as
(Skewes et al. 2006), supported by survey                              subject to overfishing (Table 18.1) The HSP
data collected in 2004. The assessment found                           indicates that any directed (targeted) fishing
that the density of sandfish had decreased                             on an overfished stock is not permitted
by 40% since the previous survey in 2002,                              and therefore amounts to overfishing.
when the stocks were already understood to                                 The change in the overfishing status
be overfished. The assessment recommended                              from 2008 (uncertain) to 2009 (subject to
maintaining a zero TAC for this species.                               overfishing) is based on the examination of
Sandfish is assessed as overfished (Table 18.1),                       data provided by the Foreign Surveillance &
based on the information presented in the                              Response Section of AFMA, relating to the



                                                  chapter 18          Torres Strait Sea Cucumber and Trochus Fisheries   329
apprehension of illegal fishers in the area of     previous assessment/s
the Torres Strait Protected Zone (TSPZ) in         A survey conducted in 1995 concluded
2009. As part of the drafting process for the      that the breeding year-class of sandfish
2009 Fishery status reports, ABARE–BRS             on Warrior Reef was depleted (Long et
sought data from AFMA on the number,               al. 1996). In 1998 a survey of sandfish on
location and associated catch of illegal fishers   Warrior Reef found that the standing stock
taking sea cucumber in the TSPZ. These             was 77.5% (63–86%) lower than in the 1995
data confirmed the existence and extent of         surveys and that the stock was considered
the illegal harvest of sandfish by Papua New       overexploited (Skewes et al. 1998). This led to
Guinea nationals on the Australian side            a reduction of the TAC in the fishery to zero.
of the Warrior Reef complex in the Torres               In 2000 a survey of sandfish revealed that
Strait in the 2009 fishing season. Whilst the      the stock was still severely depleted; it was
number of apprehensions and the recorded           estimated as 69.7% (53–81%) smaller than in
catch associated with these apprehensions is       1995 (Skewes et al. 2000). In 2002 surveys
less than that recorded for 2008, 2009 is the      of the eastern Torres Strait and the Warrior
first year ABARE–BRS has sought evidence           Reef complex (Skewes et al. 2004) found
of these activities and therefore been able to     that, although abundance at sites repeated in
support the assertion that there is illegal take   2002 was 21.4% greater than in 2000, it was
of sandfish in the TSPZ. This investigation        still less than half that observed in 1995. The
has led to a change in stock status.               bulk of the sandfish observed were larger,
    ABARE–BRS understands that illegal             two-year-old animals, giving potential for
fishing on the Australian side of Warrior Reef     good recruitment. As the sandfish population
complex by Papua New Guinea nationals              was considered overexploited in 1995, it
ended in mid 2009. This is understood              was also considered overexploited in 2002.
to have resulted from the close of the
Papua New Guinea sea cucumber fishery              Future assessment needs
(implemented 1 October 2009) and may also          The reporting of sea cucumber catch in this
be the result of an increase in compliance         fishery is not mandatory for TIB fishers.
activity in 2008 (AFMA pers. comm.).               Understanding catches is an important
                                                   component of the management of stocks,
reliability of the assessment/s
                                                   ensuring sustainability and maximising
The abundance estimates derived from               economic return to fishers. The analysis of
the surveys undertaken between 1998 and            catch and effort data is also an important
2004 can be considered reliable, given the         component of the assessment of the
established and repeated methodology. The          status of stocks. Effective reporting of
general survey of marine resources that            catch and effort data should be addressed
resulted in the 1995 assessment (Long et al.       as a priority. Some validation of catch
1996) for sandfish is considered less reliable,    composition would also be a valuable
due to the untargeted nature of the survey         addition to the management of this fishery.
design and the low precision of results.               The data from the 2010 survey of the
    The back-calculation of densities required     Warrior Reef are currently being analysed.
to support the catch taken in 1995 is a            The results of this work are likely to
relatively coarse estimation method (Skewes et     inform the status determination process
al. 2006). However, it is sufficient to provide    in subsequent Fishery status reports.
an indication of the density of sandfish on
the Warrior Reef complex before the recent
exploitation period, starting in about 1995.




330     Fishery status reports   2009
Surf redfiSh                                                                Preliminary indications from the most
(Actinopyga maurtiania)                                                 recent survey report of sea cucumbers in
                                                                        the east Torres Strait (Skewes et al. 2010)
                                                                        suggest that surf redfish has never been a
                                                                        significant part of the commercial catch of
                                                                        sea cucumbers in the Torres Strait and has
                                                                        probably always occurred at low densities.
                                                                        The authors suggest that the catch reported as
                                                                        surf redfish was more likely to be deepwater
LINE DRAWING: FAO                                                       redfish (Actinopyga echinites) and a suite
                                                                        of blackfish species (Actinopyga spp.).
ta B l e 1 8 . 7        Biology of surf redfish
                                                                            Skewes et al. (2010) indicate that most
                                                                        of the reported historical catch of ‘redfish’
  Parameter                 Description
                                                                        has come from the shallow banks on, or
  General                   A relatively small sea cucumber,            adjacent to, the Warrior Reef complex and
                            typically found in shallower habitats
                            on outer or fringing reefs. Thought to      Great North East Channel (GNEC). The
                            be most abundant in high-energy             authors estimate the distribution of surf
                            environments. Can reach relatively
                            high densities (>1 individual/m2).          redfish to be predominately in the eastern
                                                                        Torres Strait. However, given that the density
  Range                     Species: Recent survey report
                            indicates distribution in eastern Torres    estimates of surf redfish and the quantity
                            Strait.                                     of catch of this species through the history
                            Stock: The area of the Torres Strait
                            Protected Zone.                             of the fishery are both uncertain, the stock
  Depth                     Relatively shallow: <20 m
                                                                        is assessed as uncertain with regard to the
                                                                        overfished status. The Warrior Reef complex
  Longevity                 Not known
                                                                        was resurveyed (primarily for sandfish) in
  Maturity (50%)            age: not determined                         early 2010. The results of this work may
                            Size: 370 g; 220 mm TL
                                                                        also inform the status determination for
  Spawning season           Warmer months of the year
                                                                        surf redfish when they are available.
  Size                      Maximum: 350 mm; 1 kg whole                     Although reporting of sea cucumber catch
                            weight
                            Recruitment into the fishery:               of in the Torres Strait is not mandatory, it is
                            minimum size limit 220 mm TL                understood that there was no domestic fishery
TL = total length                                                       for sea cucumbers in the Torres Strait in
S OU R C E S :   Conand (1989, 1998); Kinch (2008); www.pzja.           2009. On this basis, surf redfish is assessed
gov.au.                                                                 as not subject to overfishing (Table 18.1).

stock status determination                                              reliability of the assessment/s
Surf redfish has previously been determined                             Reliability of the assessments is the same as
as overfished and uncertain with regard to                              for black teatfish.
the overfishing classification. The overfished
                                                                        previous assessment/s
determination was made using the information
                                                                        Previous assessments are the same as for black
presented in the previous two assessment
                                                                        teatfish.
reports (Skewes et al. 2004; 2006). These
indicated that surf redfish was overexploited                           Future assessment needs
and recommended a zero TAC for this species.                            Future assessment needs are the same as
The uncertain classification for overfishing in                         for sandfish. Additionally, reconciliation
recent years was made on the basis that the                             of the prevalence of surf redfish in the
extent of illegal, unregulated and unreported                           historical catch records for this fishery should
(IUU) fishing could not be confirmed.                                   be undertaken as a matter of priority.


                                                  chapter 18           Torres Strait Sea Cucumber and Trochus Fisheries   331
White teatfiSh                                                       at low densities in the Torres Strait and that
(Holothuria fuscogilva)                                              the level of fishing that was applied between
                                                                     1995 to 2005 did not adversely affect the
                                                                     stock. Additionally, white teatfish, which
                                                                     spans a relatively broad range of depths
                                                                     (10–40+ m), is probably protected to some
                                                                     extent at greater depths by the prohibition on
LINE DRAWING: FAO
                                                                     use of breathing apparatus when fishing for
ta B l e 1 8 . 8         Biology of white teatfish                   sea cucumbers in the Torres Strait. Although
                                                                     the proportion of the stock that is protected
  Parameter                 Description                              is unknown, there is some inbuilt protection
  General                   A relatively large sea cucumber,
                                                                     in the management arrangements of the
                            typically found on reef edge or slope,   fishery. It is also possible, given this broad
                            and outer barrier reef habitats          depth range of the species, that surveys in
  Range                     Species: Likely to have a broad          the Torres Strait (limited to maximum depth
                            distribution throughout the fishery,
                            particularly in the east
                                                                     of 20 m) may underestimate the density of
                            Stock: The area of the Torres Strait     the stock and, as a result, the biomass.
                            Protected Zone                               Although reporting of catch of sea
  Depth                     10–40+ m                                 cucumbers by TIB fishers in the Torres
  Longevity                 12+ years                                Strait is not mandatory, it is understood
  Maturity (50%)            age: not determined
                                                                     that there was no domestic fishery for sea
                            Size: 1175 g; 320 mm TL                  cucumbers in the Torres Strait in 2009.
  Spawning season           Warmer months of the year                On this basis, white teatfish is assessed as
                            (November–February)                      not subject to overfishing (Table 18.1).
  Size                      Maximum: 570 mm; 5.2 kg whole
                            weight                                   reliability of the assessment/s
                            Recruitment into the fishery:
                            minimum size limit 320 mm TL             The abundance estimates derived from the
                                                                     surveys undertaken in 2002, 2005 and 2009 can
TL = total length
                                                                     be considered reliable, given the established
S O UR C E S :   Conand (1989, 1998); Kinch (2008); www.pzja.
gov.au.                                                              and repeated methodology. A survey conducted
                                                                     in 1995 concluded that there were substantial
stock status determination                                           populations of a number of species of sea
The most recent survey of sea cucumbers                              cucumber in the east of the Torres Strait,
in the Torres Strait was undertaken in 2009                          but that further survey work was required to
(Skewes et al. 2010). Preliminary data from                          reliably estimate abundance (Long et al. 1996).
this survey indicate that the mean density
of white teatfish had increased from the                             previous assessment/s
previous survey in 2005 (Skewes et al.                               In 2008 white teatfish was classified as
2010). Mean length and weight had also                               uncertain with regard to both the overfished
increased. However, there is considerable                            and overfishing classification because:
uncertainty around these mean estimates.                             •	 there was insufficient information
    In 2009 white teatfish is assessed as not                            to ascertain the health of the
overfished on the basis that the stock has                               biomass, other than the ‘exploitation’
maintained relatively stable and low densities                           classification (Skewes et al. 2004),
(<1 individual/ha) over the past four surveys                            which was poorly understood
(1995 to 2009), during which time there                              •	 the extent of IUU fishing was not known.
has been some fishing of the species. This                           Previous stock assessments are detailed
suggests that white teatfish are naturally found                     under black teatfish.



332              Fishery status reports   2009
Future assessment needs                                reliability of the assessment/s
Future assessment needs are                            Reliability of the assessments is
the same as for sandfish.                              the same as for black teatfish.

                                                       previous assessment/s
other Sea cucumberS                                    Previous assessments are the
                                                       same as for white teatfish.
stock status determination
                                                       Future assessment needs
The ‘other sea cucumber’ stock in the Torres
                                                       Future assessment needs are
Strait comprises as many as 18 species.
                                                       the same as for sandfish.
Results from the 2009 survey (Skewes et al.
2010) indicate that the densities of deepwater
redfish (Actinopyga echinites) and hairy
blackfish (A. miliaris) have increased since           trochuS
the previous survey in 2005. Skewes et al.             (Trochus niloticus)
(2010) also indicate that deepwater redfish
and a suite of blackfish species are likely to
have made up what was historically reported
as surf redfish catch. It is therefore difficult
to know what the observed densities in
2009 imply for the health of these stocks.
    The 2004 assessment (Skewes et al. 2004)
provided an exploitation classification for a
number of other sea cucumber species that are          LINE DRAWING: FAO
contained within this basket stock. None of
these species were found to be overexploited.          ta B l e 1 8 . 9   Biology of trochus
    Species-specific catch for this ‘stock’
(group of species) is not well understood.              Parameter             Description
The Australian catch of sea cucumbers                   General               Asynchronous spawners that may
in the Torres Strait between 1996 and                                         form loose aggregations to spawn.
                                                                              The short planktonic duration of
2005 was variable (Skewes et al. 2010).                                       trochus larvae before settlement
Blackfish catch peaked at 28.5 t (gutted                                      (~3 days) is understood to limit
weight) in 2001. The total catch of other                                     the dispersal range of this species.
                                                                              Recruitment may be limited
species peaked at 14.5 t in 2002.                                             by suitable juvenile habitat.
    Given the number of species that comprise
                                                        Range                 Species: Indo-Pacific distribution
this stock, it is difficult to determine a suitable                           Stock: The area of the Torres Strait
status classification. On this basis, the ‘other’                             Protected Zone.
sea cucumber stock is assessed as uncertain             Depth                 Most common range 0–10 m
with regard to the overfished status.                   Longevity             12–15 years
    Although reporting of catch of sea
                                                        Maturity (50%)        age: 2–3 years
cucumbers in the Torres Strait is not                                         Size: 55–77 mm basal diameter
mandatory, it is understood that there was              Spawning season       Year round
no domestic fishery for sea cucumbers in
                                                        Size                  Maximum: ~170 mm (basal
the Torres Strait in 2009. On this basis,                                     diameter)
other sea cucumbers are assessed as not                                       Recruitment into the fishery:
subject to overfishing (Table 18.1).                                          minimum (80 mm basal diameter)
                                                                              and maximum (125 mm basal
                                                                              diameter) size limits for commercial
                                                                              harvest
                                                       SOURCES : FAO (1998); SPC (2008); Murphy et al. (2009).




                                     chapter 18       Torres Strait Sea Cucumber and Trochus Fisheries               333
stock status determination                       reliability of the assessment/s
The most recent broad-scale survey of trochus    Considerable uncertainty is associated with
stocks in the Torres Strait was undertaken in    the preliminary results of the 2009 survey,
2009 (Murphy et al. 2009), combined with the     stemming from the survey design and the
survey of sea cucumbers. The survey covered      small number of sites where trochus was found.
113 sites over 10 days. Preliminary results of
this work indicate that a total of 62 trochus    previous assessment/s
were found at 12 of the 113 sites. Although      There are no previous, full-scale targeted
survey transects went down to a depth of         assessments of trochus in the Torres Strait.
20 m, trochus was only found down to 3 m.        A general reef resources survey was
    A geographic information system was          undertaken in 1995 (Long et al. 1996), but
used to estimate habitat area, and the           the results for trochus were not published.
survey data provided estimates of density
and size (basal width). Trochus weight           Future assessment needs
was estimated through a length–weight            Reporting of trochus catch in the fishery is not
relationship previously established for          currently mandatory for TIB fishers; however,
Torres Strait trochus (Long et al. 1993).        understanding catches is important for
    A total of 1.5 t of trochus was reportedly   assessment of the status of stocks. This should
taken in the Torres Strait in 2009. This         be addressed as a priority for the fishery.
is the smallest reported catch since 1987
(Murphy et al. 2009). Given the low levels
of catch in 2009, relative to historical         18.5    e c o n o m i c s tat u s
levels, the stock is assessed as not subject
to overfishing (Table 18.1). Preliminary
                                                 No economic information is
results from Murphy et al. (2009) propose
                                                 available for this fishery.
a catch trigger of 75 t for this fishery (20%
of the standing biomass estimate).
    Given the small number of sites where
trochus was found (12 of 113), there is          18.6    e n v i r o n m e n ta l
considerable uncertainty in the survey                   s tat u s
results. The authors conclude that densities
of trochus in ‘trochus habitat’ are similar      Because of the selective nature of these
to healthy populations outside of Australia.     hand collection fisheries, there is understood
Mean densities across the Torres Strait are      to be relatively little direct impact on
higher than the mean estimate from the 1995      the benthos or other marine species.
reef resources inventory (when the GNEC              The sessile nature of both sea
is included in the analysis). However, since     cucumbers and trochus and their relatively
the fishery was active before this survey,       restricted mobility make them inherently
the health of the population in 1995 is          vulnerable to localised depletion.
unknown. Although valuable information
is provided by this work, the level of
                                                 threatened, endangered and
uncertainty in the preliminary results is too
great to resolve the overfished status for       protected species
2009. On this basis, Torres Strait trochus       The selective nature of the fishery minimises
is assessed as uncertain with regard to          any direct effects of fishing on threatened,
the overfished classification (Table 18.1).      endangered or protected species.




334     Fishery status reports   2009
benthic habitats                                            18.8      l i t e r at u r e c i t e d
Fishing for sea cucumbers and trochus in
the Torres Strait is conducted either through               Conand, C 1989, The Fishery Resources of
reef-top walking or free-diving. The impact                    Pacific Island Countries: Part 2.
of these collection methods is unquantified,                   Holothurians. FAO Fisheries Technical
however they are suspected to be low.                          Paper, No. 272.2. FAO, Rome.
                                                            ——1998, ‘Holothurians’, in KE Carpenter &
                                                             VH Niem (eds), United Nations Food and
                                                             Agriculture Organization species
18.7        h a r v e s t s t r at e g y
                                                             identification guide for fishery purposes.
            perFormance
                                                             The living marine resources of the Western
                                                             Central Pacific, vol. 2, Cephalopods,
Not applicable.                                              crustaceans, holothurians and sharks,
                                                             FAO, Rome.
                                                            DAFF (Australian Government Department of
                                                              Agriculture, Fisheries and Forestry) 2007,
                                                              Commonwealth Fisheries Harvest Strategy,
                                                              policy and guidelines, DAFF, Canberra.
                                                            FAO (Food and Agriculture Organization of the
                                                              United Nations) 1998, ‘Seaweeds, corals,
                                                              bivalves and gastropods’, in KE Carpenter
                                                              & VH Niem (eds), United Nations Food
                                                              and Agriculture Organization species
                                                              identification guide for fishery purposes.
                                                              The living marine resources of the Western
                                                              Central Pacific, vol. 1, Seaweeds, corals,
                                                              bivalves and gastropods, FAO, Rome.
Dried sea cucumber trade       PHOTO: DAV I D W I L SON,
                                                            Kinch, J, Purcell, S, Uthicke, S & Friedman, K
A BA R E – BRS
                                                               2008, ‘Population status, fisheries and trade
                                                               of sea cucumbers in the Western Central
                                                               Pacific’, in V Toral-Granda, A Lovatelli &
                                                               M Vasconcellos (eds), Sea cucumbers. A
                                                               global review of fisheries and trade, FAO
                                                               Fisheries and Aquaculture technical paper
                                                               no. 516, FAO, Rome, pp. 7–55.
                                                            Long, BG, Poiner, IR & Harris, ANM 1993,
                                                               ‘Method of estimating the standing stock of
                                                               Trochus niloticus incorporating Landsat
                                                               satellite data, with application to the
                                                               trochus resources of the Bourke Isles,
                                                               Torres Strait, Australia’, Marine Biology,
                                                               vol. 115, pp. 587–93.
                                                            ——Skewes, TD, Dennis, DM, Poiner, IR,
Dried sea cucumber
PHOTO: K AT H RY N R EA D, DEW H A
                                                             Pitcher, CR, Toranto, TJ, Manson, F, Polon,
                                                             P, Karre, B, Evans, C & Milton, D 1996,
                                                             Distribution and abundance of beche-de-
                                                             mer on Torres Strait reefs, CSIRO Division
                                                             of Fisheries final report, Queensland.

                                          chapter 18       Torres Strait Sea Cucumber and Trochus Fisheries   335
Murphy, NE, McLeod, I, Skewes, TD,               Stutterd, E & Williams, G 2003, The future of
  Burridge, C & Rochester, W 2009, Torres           bêche-de-mer and trochus fisheries and
  Strait hand collectables, 2009 survey:            aquaculture in Australia, Bureau of Rural
  trochus, CSIRO Marine and Atmospheric             Sciences, DAFF, Canberra.
  Research, Cleveland, Queensland.               Uthicke, S, Welch, D & Benzie, JAH 2003,
Raudzens, EE 2007, Torres Strait Trochus and        ‘Slow growth and lack of recovery in
   Beche-de-mere Fishery Data Summary               overfished holothurians on the Great
   2005 and 2006, Logbook Program,                  Barrier Reef: evidence from DNA
   AFMA, Canberra.                                  fingerprints and repeated large-scale
Skewes, T, Burridge, CM & Hill, BJ 1998,            surveys’, Conservation Biology, vol. 18,
   Survey of Holothuria scabra (sandfish) on        pp. 1395–404.
   Warrior Reef, Torres Strait, report to the
   Queensland Fisheries Management
   Authority, CSIRO Division of Marine
   Research, Queensland.
——Dennis, DM & Burridge, CM 2000,
 Survey of Holothuria scabra (sandfish) on
 Warrior Reef, Torres Strait, final report to
 the Queensland Fisheries Management
 Authority, CSIRO Division of Marine
 Research, Queensland.
——, ——Koutsoukos, A, Haywood, M,
 Wassenberg, T & Austin, M 2004, Stock
 survey and sustainable harvest strategies
 for Torres Strait bêche-de-mer, AFMA
 project no. R01/1345, CSIRO Division of
 Marine and Atmospheric Research,
 Cleveland, Queensland.
——Murphy, N. E, McLeod, I, Dovers, E,
 Burridge, C & Rochester, W. 2010. Torres
 Strait hand collectables, 2009 survey: sea
 cucumber, CSIRO, Cleveland.
——Taylor, S, Dennis, D, Haywood, M &
 Donovan, A 2006, Sustainability
 assessment of the Torres Strait sea
 cucumber fishery, CRC TS project task no.
 T1.4, final report, CSIRO Division of
 Marine and Atmospheric Research,
 Cleveland, Queensland.
SPC (Secretariat of the Pacific Community)
  2008, ‘Trochus and other marine mollusks’,
  Trochus Information Bulletin, issue 14, July
  2008.




336     Fishery status reports   2009

								
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