NT TREPANG FISHERY - 2011
Progress in implementing the Department of Sustainability, Environment, Water, Population and
Communities recommendations made in the 2007 assessment of the NT Trepang Fishery, April 2011
In December 2007, the NT Trepang Fishery was re-accredited under Part 13A of the Environment Protection and Biodiversity
Conservation Act 1999 (EPBC Act). The assessment resulted in the fishery being declared an approved Wildlife Trade Operation (WTO)
and exempt from the export regulations of the EPBC Act for a period of three years.
The declaration was subject to a number of conditions and recommendations being agreed to and implemented before the next
Australian Government review of the fishery in 2010, or within the timeframes specified in individual recommendations. These agreed
recommendations are focused on ensuring the continuation and enhancement of good management practices. This document
specifically addresses these recommendations and provides a response to each.
The document should be read in conjunction with the Annual Fishery Status Reports (available for download from
www.nt.gov.au/DoR/Fisheries) and the initial assessment document that was provided to the Department of Sustainability, Environment,
Water, Population and Communities (DSEWPaC) (formally the Department of Environment, Water, Heritage and the Arts) in 2004.
The following progress has been made by DoR in implementing the DSEWPaC conditions and recommendations:
Condition/Recommendation
Progress
Condition 1: “Operation of the NT Trepang Fishery will be carried out in
accordance with the management regime in force under the NT Fisheries
Regulations 1995 and the NT Fisheries Act 1988.”
Condition met
Condition 2: “DOR to advise SEWPaC of any intended change to the NT
Trepang Fishery management arrangements that could affect the
assessment of the fishery against the criteria on which EPBC Act decisions
are based.”
Condition met
Condition 3: “DOR to produce and present reports to SEWPaC annually as
per Appendix B to the 'Guidelines for the Ecologically Sustainable
Management of Fisheries -2nd Edition.”
Condition met
The management of the Trepang Fishery is undertaken in strict accordance
with the requirements and guidelines of the NT Fisheries Act 1988 and the
NT Fisheries Regulations 1995. All new entries into the fishery are required
to undertake an induction interview during which the regulations, licence
conditions and protected species considerations are clearly outlined.
DOR has kept SEWPaC informed of any proposed amendments to the
management regime for the Trepang Fishery through the publication of the
Current Issues and Future Plans sections in the annual Fishery Status
Reports. This practice will be continued in future Fishery Status Reports and
any changes to the management arrangements for the fishery will be
advised to SEWPaC through subsequent annual Fishery Status Reports. In
addition, DOR and SEWPaC officers have maintained informal
communication channels and this has ensured that SEWPAC is kept
informed of any emerging issues in the fishery.
A copy of the Fishery Status Reports are provided to SEWPaC each year
with a supporting document outlining progress in meeting SEWPaC’s
recommendations and conditions for the fishery. Copies of the annual
Fishery Status Reports are available to download at
http://www.nt.gov.au/d/Fisheries/
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Recommendation 1: “Through continued collaboration with other
jurisdictions, DoR to continue to identify and implement key research
priorities regarding the biology and ecology of H.scabra.”
Ongoing
DoR are continuing to liaise with Queensland and Western Australia to
develop ways of undertaking further cost-effective research. There are
strong links between the management arrangements in WA and the NT with
the fisheries being very similar in species composition and environment.
Additionally, the sole operator across these areas, Tasmanian Seafoods is
able to provide a good link to ensure cooperative and complimentary
research across the relevant states and territories.
Collaborative hatchery, growout, and broodstock husbandry research
between Tasmanian Seafoods and DoR has led to the development of a
commercial scale hatchery at the Darwin Aquaculture Centre. This hatchery
is now capable of producing 30,000 – 50,000 juvenile sandfish in regular
production runs. Complimentary pond grow-out trials indicate sandfish are
capable of reaching market size in 12 months.
Collaborative work between Tasmanian Seafoods, Flinders University, the
South Australian Research and Development Institute and DoR is
continuing on a genetic study titled ‘Population genetic structure of Sea
Cucumbers (bêche-de-mer) in Northern Australia’. Spatial sampling of
genetic stocks has been carried out across 15 sites in the NT and
development of the genetic markers has progressed well. Initial analysis has
shown some slightly unexpected results; this will be resolved with continued
temporal sampling and analysis of genetic data from single pair matings
through the hatchery.
The results of this project will determine the genetic structure of trepang
stocks in NT waters, and assist in identifying if there are geographically
distinct populations within the fishery.
Tasmanian Seafoods also undertook a pilot survey of sandfish stocks using
a “stalled plate” trawl gear in 2009. Results from this survey were
inconclusive due to survey design and technical difficulties. However,
sandfish have previously been successfully sampled in the NT using smaller
versions of similar gear deployed from smaller vessels. Tasmanian
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Seafoods is currently evaluating the existing trawl gear and survey design
with a view to recommence surveys with modified gear and survey design in
2011.
Despite this ongoing cooperative research, many information gaps still exist
with regard to NT stocks, including life history parameters, abundance and
stock structure. To date, the majority of information on hand has been
provided by research undertaken on similar species in other jurisdictions.
As a consequence, DoR has implemented precautionary management
arrangements that include limiting the fishing area, gear type and licensed
operators in the fishery (Tasmanian Seafoods currently own all six licences).
Recommendation 2: “Within 2 years, DoR to commence developing
meaningful precautionary yield estimates for H.scabra in the NT Trepang
Fishery, with the aim to commence implementing yield estimates within
three years.”
Ongoing
Meaningful precautionary yield estimates for the NT Trepang Fishery are not
yet available due to the inconclusive results of the initial trawl survey
methods. Obtaining these estimates has also been delayed by the highly
variable nature of the catch and effort data in the NT Trepang Fishery. DoR
fisheries scientists are currently assessing the viability of using exploitation
rates of trepang populations as a surrogate for calculating yield estimates.
In addition, results on the stock structure project must first be obtained to
identify the exploitation rates of individual populations of sandfish. In the
interim, DoR considers the current catch levels to be sustainable and the
fishery not to be under threat of overfishing. Low effort levels (three active
licences) across a broad geographical range provide protection from
overfishing and any perceived threat to sustainability.
The status of the fishery is assessed through completion of the Annual
Status Report and at the annual Northern Australian Fisheries Management
Workshop. As sustainable yield estimates are not currently available, key
variables are monitored to ensure that conditions and trends, principally
species composition, catch, effort, CPUE, areas fished, average size of
trepang and licensee ownership are consistent with ensuring the
sustainability of the NT trepang resources (See Table 1). As yield estimates
become available, further specific indicators and triggers can be developed
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to monitor the performance of management objectives. In the interim,
precautionary management arrangements adopted by DoR ensures that
there is a high probability of the fishery not exceeding sustainable harvest
levels, acknowledging that historical limits were a significant magnitude
higher than current catch.
Recommendation 3: “Using information and research relevant to the
fishery, DoR to review the current limit reference points for H.scabra, to
ensure that they provide a precautionary basis to detect changes and
impacts on the stock.”
Complete
DoR researchers and managers, together with industry representatives,
have reviewed the current limit reference points for sandfish to determine if
they are providing a precautionary basis to detect changes and impacts to
the target stock. The review included the latest available literature and
known research, and the biological characteristics of the target species.
The review determined that the multi-faceted approach DoR is presently
employing ensures the general health of the fishery. The current limit
reference points are considered sufficiently precautionary in making certain
the fishery will continue to be managed in a manner that will not lead to
over-fishing.
The limit reference points and a brief description of recent developments are
as follows:
1. Triggers to be refined when yield estimates are developed.
At present the triggers cannot be refined as valid yield estimates for
target species have not been developed. The research program has
been unable to provide meaningful yield estimates to date as a result of
the highly variable catch and effort information and technical difficulties
encountered during the trawl surveys. However, continued collaborative
research between Tasmanian Seafoods and DoR are working towards
obtaining this information.
2. Total catch increases to over 300 t/year.
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The 2009 catch was 52.3 tonnes, well below the trigger of 300 tonnes.
As above, until information from the research and monitoring program is
available to refine the trigger, the trigger of 300 tonnes is considered to
be a suitably precautionary figure based on high historic catch levels.
The relatively low harvest level in 2009 is attributed to a business
decision by the trepang fishery licensee to concentrate available effort in
other jurisdictions, and a reflection of the difficulties in recruiting and
retaining experienced divers and skippers to work in the fishery. During
this time Tasmanian Seafoods also directed some resources to the
ranching and aquaculture of trepang.
It is noted that whilst the 2009 harvest falls well short of the trigger of
300 tonnes, not all licences are currently active in the fishery and the
trigger level is to allow for expected sustainable growth within the
fishery.
3. The rolling three year average CPUE varies by a factor of 30%.
Fluctuations in CPUE are expected in a developing fishery and can
occur for reasons unrelated to changes in trepang biomass (e.g. interannual fluctuations in water clarity, prevailing weather conditions and
skipper experience). To even out these variations it is considered
appropriate to smooth these perturbations by averaging CPUE over the
last three reporting periods and basing any trigger on those figures.
Again, during the developmental phase it is more appropriate to look for
trends or downswings such as occurred in Torres Strait and Great
Barrier Reef (GBR) trepang fisheries. As such, the interim trigger point
is set so that if there is variation of 30% on the three year average
CPUE, a review of management arrangements will occur and
appropriate remedial action undertaken (Table 1).
The 2009 CPUE value was 3% higher than the rolling three year
average, therefore the trigger reference point was not reached.
The department will continue to monitor the CPUE of trepang in the
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fishery.
4. Weighted average decreases by more than 20%.
The average weight of trepang harvested since 1997 has remained
relatively constant. A decline in the average weight is considered an
appropriate trigger as this may indicate a reduction in the average size
of individuals in the population. As such, a trigger will be activated if the
weighted average of H. scabra decreases by more than 20% (Table 1).
The average individual weight increased by 35% in 2009, therefore the
trigger reference point was not reached.
The department will continue to monitor the average size of trepang in
the fishery.
5. Catch of trepang species other than H. scabra increases to over
30% of total catch.
Based on occurrences in other jurisdictions a change to targeting other
or lower grade species has often preceded a collapse, or could be
considered as evidence of overfishing in the fishery. As such, it is
considered prudent to retain a trigger that will be activated if the catch of
species other than H. scabra increases to more than 30% of the total
catch (Table 1). H. scabra currently makes up 100% of the reported
catch.
No other species of trepang were recorded as harvested over the
reporting period.
6. Any licences traded.
The NT Trepang Fishery has stable licensing arrangements with
Tasmanian Seafoods currently owning all licences. This company also
has trepang access rights in other jurisdictions (WA, Qld and the Coral
Sea) and spreads its fishing resources throughout these areas.
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Consequently, there is no “Gold Rush” mentality within the NT industry
as there would be little benefit in overexploiting the resource for short
term gain. However, if licences were traded the same level of resource
stewardship may not necessarily be evident. It is therefore considered
prudent to retain a trigger that will be activated if any licences are
traded (Table 1).
No licences were traded over the reporting period.
The research and monitoring project being developed for the NT Trepang
Fishery aims to provide further information that will help refine these trigger
points through a robust and scientifically validated process. When
additional information becomes available, more specific indicators and
triggers will be developed to monitor the performance of management
objectives.
Recommendation 4: “Within 12 months, DoR to develop and implement
appropriate data collection, reporting and management measures to
mitigate the risk of localised and serial depletion.”
Complete
Logbooks have been amended and now record harvest areas in GPS
coordinates. This has allowed the collection of finer spatial data to mitigate
the risk of localised or serial depletion.
Additionally, the NT Manager for Tasmanian Seafoods has developed a
harvest area rotation roster for skippers. This has been done to maintain
high catches however it will also assist in guarding against potential
localised depletion.
Recommendation 5: “Within 2 months of a species other than H. scabra
being harvested in the fishery, DoR to develop precautionary reference
points for that species.”
Ongoing
H. scabra is currently the exclusive target species in the fishery and there
are no records of species other than H. scabra landed for the fishery. If
sufficient quantities of other species become available and they can be
harvested sustainably in economic quantities, then a species-specific interim
reference point for that species will be developed.
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Table 1:
Species/Group
Management Objectives, Performance Indicators, Interim Trigger Points and Management Actions Used in the NT
Trepang Fishery
Management
objectives
Target species Ensure
intergenerational
equity by
maintaining
ecologically
sustainable annual
catches in all
sectors
Performance indicators
Interim Limit reference point
Management response to be taken
1. Sustainable yield
estimates developed
2. Change in total catch
1. Triggers to be refined when yield
estimates developed
2. Total catch increases to over
300t/year.
3. The rolling three year CPUE
average varies by a factor of
30%.
4. Weighted average decreases by
more than 20%.
5. Catch of trepang species other
than H. scabra increases to over
30% of total catch.
6. Any licences traded.

NA - no byproduct in fishery
NA
3. Change in CPUE
4. Change in average
weight
5. Change in catch
composition
6. Change in licence
ownership
Byproduct &
bycatch
species
Ensure
sustainability of
byproduct and
bycatch species
taken in the NT
Trepang Fishery
Monitoring logbooks



Director to be notified within 60 days
if trigger reached
An internal examination of cause and
implication of reference point being
triggered with report prepared within
six months to Director
Consultation with industry and other
stakeholders on need for alternate
management strategy or action if
necessary and agreement on line of
action
If appropriate, any amended
arrangements to be implemented
within 12 months of trigger being
reached
Onboard monitoring
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