Principle 1: A fishery must be conducted in a manner that does not lead to over-fishing, or for those stocks that are over-fished, the fishery must be conducted such that there is a high degree of probability the stock(s) will recover
Department of the Environment and Heritage, December 2001
ISBN 0 642 54859 5
Objective 1: The fishery shall be conducted at catch levels that maintain ecologically viable stock levels at an agreed point or range, with acceptable levels of probability.
The information collection system for the fishery comprises a substantial paper trail, with the following reports required: catch logbook; unloading; fish cauf (placing lobster in a holding tank); leaving port (to commence fishing); movement (of lobster from one place to another); dispatch (selling lobster outside Tasmania); and commercial quota docket. Logbook data is required in (30nm)2 blocks. Validation is conducted between catch logbooks and quota landings. The settlement of puerulus (the final larval stage, at which lobster "settle" on coastal reefs) also is monitored as a means of predicting the magnitude of future recruitment. Monitoring also should enable the detection of periods of likely prolonged low puerulus settlement.
The bulk of data are collected from sources that are dependent on the commercial fishery. Fishery independent data are obtained from a catch sampling program addressing exploitation rates, in which two locations are sampled before the season opens, mid-season, and towards the end of the season. Results from independent sampling seem to support the fishery-dependent data.
DPIWE suggest that the quota control system represents sufficient deterrent, with discrepancies followed up shortly after receipt of catch return (discrepancy of estimated catch being 1.5% less than recorded landings); and that in the main catch records match quota records; as a result they consider the data are reliable.
Assessments of the status of the rock lobster resource are conducted annually against performance indicators compared with triggers, with a view to developing recommendations regarding the level at which the TACC should be set. The stock assessment uses a model specifically developed for the fishery. The assessment is made against the following performance indicators: the sustainability of the target species (catch levels, CPUE, estimates legal size biomass, egg production, puerulus settlement, fleet size, estimates of recreational catch, recreational licence numbers, byproduct species landings); levels of bycatch; and impact on endangered or threatened species.
Problems with the model which resulted in over-estimates of legal size biomass in the final year of time series have been identified and currently are being addressed.
Under the current management regime the legal size biomass and egg production levels statewide are increasing. New trigger points have been proposed for the next 5 years' assessment.
The puerulus settlement indices, developed from settlement data, are proving useful in predicting future recruitment (five years on) to the fishery in eastern waters of the fishery (Gardner et al 2001), and more broadly may be viewed as a useful indicator of biomass. It is unclear whether the utility of the puerulus settlement indices holds for lobster harvested in western waters.
There is periodic review of the way data are collected and used, and of the model and assessment methodologies. The submission states that review will occur as and when needed. The parameters and decision points to determine whether a review is required are unclear.
The submission indicates that the level of knowledge on commercial catches is good, and the quota management system is expected to improve knowledge levels over time. In contrast, the level of knowledge of the recreational take is low. Recreational take is not directly limited by a mechanism such as a cap on total harvest, although take is limited through bag limits and compliance monitoring. The main method of assessing recreational take is through recreational surveys. DPIWE propose that future surveys take place at least every 2nd year. This should enable closer monitoring of the potential increase in recreational harvest as the number of licences continues to increase.
Both commercial and recreational components are included in stock assessments. The recreational harvest is assumed in the stock assessments to be 5% of the commercial take, however as noted earlier estimates of recreational harvest have varied from 5 to over 10%. Other possible sources of error in the stock assessment include indigenous take, for which no data are collected, and illegal harvest. There are no clear assessments of the level of illegal take, although this is thought to be low and measures have been introduced to both the commercial and recreational sectors to minimise illegal activity. Accordingly, there is a risk that the stock assessments are underestimating total removals, and as a consequence the TACC is set at too high a level. The performance of the fishery (with both egg production and legal sized biomass increasing) suggest this is not the case and the puerulus monitoring indices, working as indicators of biomass, should enable detection. Regular analysis of the results of new measures to minimise illegal activity and biennial recreational surveys should enable the detection of increases in non-commercial harvest. This would need to be combined with contingency management measures developed to deal with unanticipated levels of additional harvest. The first stage in developing such contingency measures would be the identification of an appropriate management trigger.
Estimates are made of legal size biomass ( not total biomass) using both fishery dependent (stock assessment) and independent (survey) techniques to estimate exploitation rates. This addresses the management target to rebuild legal size biomass by constraining TACC to 1,500t, but does not give a clear idea of the biomass "left" in the ecological system. The size of undersize biomass not clear; DPIWE suggest it may have increased, if the removal of legal sized animals has meant more space and/or food is available for undersized animals. The validity of this possibility does not appear to have been tested.
Reference points and triggers are in place for target (commercial (4) and recreational fisheries (1)) and byproduct species (1 reference point and trigger). Stringent triggers are established for target species (eg 5% less statewide egg production). The trigger for byproduct species is an increase by 25% of landings of byproduct species. The use of a much broader trigger for byproduct species has been done because there is no targeted research and as a result only large changes will be detectable under the monitoring regime.
The submission indicates a commitment to review the management strategies in the event that a trigger is reached, in the following manner. After an initial notification to the Tasmanian Minister, the Crustacean Fisheries Advisory Committee, the Marine Recreational Fishing Council, and fishery participants as appropriate, the Secretary of DPIWE is to undertake an examination of: a) the status of the fishery via performance indicators and any other indicator if the fishery or stock; b) a variety of management options which would provide at least 50% probability of rebuilding stocks above the trigger level within a single year; and c) implications of management options for the fishery. Following the analysis the Secretary must consult with industry, and community as appropriate, on the development of alternative management strategies. The review is to result in a report to the Tasmanian Minister and industry within three months of an initial notification that trigger points had been reached. The submission makes no blanket commitment to an immediate course of action other than this.
Although the performance of fishery since the mid 1990s re increased legal size biomass and egg production suggest current trigger points are unlikely to be reached, the lack of specific contingency management actions to be implemented when a trigger is reached is a source of concern. DPIWE assert that the capacity to implement swift action exists, as the Tasmanian Minister has the capacity to make emergency changes if an assessment indicates a need for immediate action, and presumably an emergency notification could occur at the first instance rather than at the end of the three month review.
The submission indicates that the increased legal sized biomass and levels of egg production mean that the gap between performance indicators and triggers is increasing. DPIWE propose new triggers for the next five years. This would seem to be a useful juncture at which predetermined management responses could be built into the management regime to deal with the eventuality of a trigger being reached. Such actions could include a clear performance measure at the end of the review process (eg if the issue is shown as being of concern, predetermined management action will be taken).
The fishery is not divided into separate management zones, and the minimum size limits for males and females are applied throughout the fishery. This appears to have potential impact on the reproductive capacity of Jasus edwardsii in the northern part of the fishery. Differential growth rates in Tasmanian waters mean northern lobsters grow faster than those in southern waters. The maturity of animals is more dependent on age than on size; as a consequence, lobsters in northern waters mature at a larger size than those in southern waters. The result is that female lobsters in northern waters reaching maturity at a size greater than legal size limit, and hence a high proportion (circa 50%) of the females in the northern area enter the fishery before they are mature. DPIWE are aware of this issue and indicate the situation is monitored closely. Egg production in northern waters is increasing.
In the view of Department of the Environment and Heritage, DPIWE need to continue to closely monitor the harvest of immature females in the northern waters. Consideration should be given to identifying in advance trigger points and associated management responses to be implemented if this exploitation rate develops into a more significant concern.
The management regime allows a longer fishing season on males than on females. As males grow faster than females, they enter the fishery at an earlier stage than females. This may mean that the sex ratio is at risk of becoming skewed, particularly in the south. Research in the US and New Zealand suggest that overall population reproductive success can be affected by male lobster size and abundance. Male lobsters produce a finite quantity of sperm per breeding season, and as a result there is a limit to the number of females with whom they can mate (Turner and Gardner, 2001). If a skew in the sex ratio in favour of females were to occur it may have the potential to result in females being unable to mate, which in turn may have an impact on reproductive success. The long term ecological consequences of a skewed sex ratio are not clear.
The submission indicates DPIWE have no evidence that females in the south (where the male:female ratio is greatest) are unable to find a mate in the wild.
The level of knowledge regarding the biology of juvenile rock lobster (growth rates, mortality, movement) is low and may have implications for management that is tightly focused on target species biology. During the public comment phase it was suggested that marine protected areas (MPAs) may be useful in terms of allowing females to reach a larger size and produce more eggs. DPIWE recognise that this might increase egg protection, particularly in cases where egg production is extremely low and larvae recruit into the area where they were spawned. This would require considerable work to identify the appropriate place for the MPA. The management regime may need to be refined to deal with the uncertainty regarding juvenile rock lobster biology. One approach could be to instigate further research. An alternative would be implement precautionary management responses which dealt with the uncertainty, for example by reducing TACC or increasing refugia.
The success of stock rebuilding strategies would be enhanced in a systemic sense if a specific system-based management objective were to be developed for the fishery. Such an objective would be useful in addressing the issues outlined above. The development of system-based objectives in Australian fisheries is a fairly new concept, but none the less Department of the Environment and Heritage believes DPIWE should direct some effort into assessing options for system-based management objectives and associated biological reference, target and limit levels and performance measures for application in the fishery.
There is no commitment in the management arrangements to a specific course of action if harvest by the recreational and indigenous sectors increase. The recreational harvest is of particular concern. In the course of the public comment period of this assessment it was indicated that recreational take has been underestimated in the past, that this could still be the case, and that recreational bag limits were over generous. DPIWE propose to look at options for monitoring the recreational take, rather than a recreational TAC on the grounds that a recreational TAC would be difficult and expensive to allocate, monitor and enforce. The policy document indicates that the recreational catch trigger point is 10% of the TACC in a year, at which point recreational fishing management arrangements will be reviewed to cap total or potential catch at 10% of the TACC. There are indications that recreational harvest may be approaching 10% of the commercial catch (Yearsley et al, 1999); given this, Department of the Environment and Heritage expects DPIWE to be undertaking the review outlined above.
More proactive management measures may be required to take advantage of improved monitoring arrangements, combined with triggers and set management responses should recreational take increase.
Byproduct is monitored in conjunction with annual assessment under scalefish and octopus management regimes (for example the scalefish take in the fishery is estimated at 1-2% of the scalefish fishery harvest). The submission indicates some concerns that byproduct reporting may not be accurate, with consequent implications on DPIWE's ability to detect changes in abundance. Two triggers points are applied: an increase in total byproduct landings of 25% in any one year; and an increase in the total landings of any single species by 50% in any two year period. These are to be reviewed after the first two years of reporting. A management response to increased landings of byproduct would appear to be precautionary. The use of triggers capable of detecting only large-scale change may have implications for any long-lived, slow-maturing species that are taken in the fishery, because by the time such changes are evident the species may be at risk. DPIWE commit to review management strategies should a trigger be reached.
Although the available data indicate levels of byproduct are low in comparison with other fishing methods, DPIWE might like to consider more proactive methods of managing byproduct species.
The fishery is relatively well managed and has in place a regime of measures intended to enable the stock to rebuild. Management strategies in place imply a high level of control over commercial operators (licensing, quota management system, pot limits and gear specifications, closed seasons, minimum size limits) and some control over recreational operators (licenses, gear tags, possession limits). Measures are in place to minimise illegal activity (tail clipping recreational catch, tagging domestic sales). The level of illegal activity not known, but few breaches have been recorded relative to high number of inspections. The submission indicates that since the introduction in 1998 of ITQs the fishery has responded positively, with egg production and biomass of legal sized animals increasing statewide, and suggests that if illegal activity is and continues to be low, expectations are that the fishery will continue to rebuild. However, the quota system is a relatively new management system which may have unexpected longer term impacts and DPIWE may consider it worthwhile to develop contingency arrangements.
There are a number of "gaps" in those measures which may adversely impact on the ability of the management regime to achieve the rebuilding objective. These include the heavy reliance on statewide minimum legal size limits which enables the harvest of a significant proportion of undersized females in the northern part of the fishery; and poor understanding of the absolute level of non-commercial harvests.
- The compliance and enforcement strategy should be periodically reviewed to ensure emerging compliance risks are identified and addressed.
- DPIWE should continue to monitor the situation with respect to the harvest of immature females in the northern part of the fishery to ensure any reductions in egg production or puerulus settlement are detected in a timely manner and develop a management response for implementation in the event that a major issue develops.
- In the event that a review is triggered by a breach of the performance measures the management plan should require that action must be taken to return the fishery to a stage where it will satisfy the management objectives if the review establishes that the management regime is under-performing.
- Stock assessment processes should incorporate, if not already done, a risk assessment into the ecological impact of the potential skew in sex ratio caused by a longer fishing season on males, with a view to developing appropriate management arrangements (triggers and responses) should the skew in sex ratio present a sustainability issue.
- DPIWE should develop and provide, as part of the public review process for the management arrangements for the Tasmanian rock lobster fishery in 2005, an assessment of the options for system-based management objectives and associated biological reference, target and limit levels and performance measures for application in the fishery.
- An analysis of measures to encourage the accuracy of byproduct reporting should be conducted with a view to improving data collection, assessment and management responses.
Objective 2: Where the fished stock(s) are below a defined reference point, the fishery will be managed to promote recovery to ecologically viable stock levels within nominated timeframes.
The submission indicates that the stock is in rebuilding phase after previous heavy fishing pressure. It is not below a defined reference point, and the management measures that are in place to enable the stock to rebuild addressed above would address this objective. A specific response to this objective does not appear necessary.