Assessment report of the Queensland Spanner Crab Fishery

Environmental assessment under the EPBC Act
Department of the Environment and Heritage, December 2001
ISBN 0 642 54860 9

Principle 2: Fishing operations should be managed to minimise their impact on the structure, productivity, function and biological diversity of the ecosystem:

Objective 1: The fishery is conducted in a manner that does not threaten bycatch species.

Information requirements

The submission indicates that due to the low level of bycatch in this fishery, the collection of information on bycatch has not been a priority. There is consensus among researchers, scientific observers and commercial fishers that bycatch levels in this fishery are extremely small. The small amount of bycatch that is taken consists primarily of crustaceans (mainly portunid crabs), due to the dilly's construction aimed at entangling spanner crabs, with juvenile flathead (Platycephalidae), flounder (Bothidae) and a range of gastropods, and other marine invertebrates also occasionally taken.

Currently the only information collected on bycatch in this fishery is through the Long Term Monitoring Program. Bycatch data was collected in the May 2001 survey however the submission does not report the results, with the exception of region 2.

The submission identifies the need for qualitative data on bycatch species and states that it will be collected in the 2002 Monitoring Program survey. It is important to note that the surveys began in April 2000 so no real time series data exists. It is unclear what the scale of the survey will be, what data will be collected etc. EA requests that the results of the survey be made publicly available and should an increase in bycatch be detected at the species or system scale, appropriate management responses will be employed.

To complement the fishery-independent bycatch information being collected by the Long Term Monitoring Survey it would be extremely useful for the ongoing management of the fishery to collect fishery-dependent information on bycatch. Sound fishery-dependent information on bycatch would help confirm the bycatch risk assessment, quantify bycatch at the species and system level, and highlight any system or species changes in bycatch. Modification of the current daily logbook to incorporate a reporting mechanism for bycatch, including information on quantities, species and action taken, would be a simple way to achieve this end. EA strongly recommends the development of a reporting mechanism and believes that given the low bycatch level in the fishery it would not be an onerous or time consuming task for the fishers. Overall the information collection system in place is appropriate to the scale of the fishery. The inclusion of the logbook reporting requirements will improve the fishery's ability to monitor changes in bycatch and respond appropriately in a timely manner.

Assessment

The submission indicates that no formal risk assessment of bycatch has been undertaken due to the very low bycatch levels in the fishery. QFS consider that the risks of significant impact on the bycatch is very low and those animals that are caught are returned quickly to the water with a high chance of survival. In recognition of the low bycatch levels EA does not consider it pertinent that a formal risk assessment be undertaken. The Long Term Monitoring Program will play a vital role in monitoring the impact of the fishery on bycatch species and it is recommended that work be continued to collect information on bycatch from the fishery.

Management response

The low bycatch levels in this fishery have not warranted the development of measures to minimise bycatch in this fishery. There are currently no formal measures in place to avoid the capture and mortality of bycatch species, however, the structure, deployment and retrieval of the fishing gear are such that the gear is highly selective, catching little bycatch, providing high survivability and causing minimal damage to those species captured.
Whilst current bycatch rates are low the submission provides no clear indication of the long-term sustainability of these bycatch levels. A current lack of qualitative and quantitative bycatch data has been identified by QFS and they have committed to collecting such data through the Long Term Monitoring Project. Information collected from these surveys should provide valuable information for monitoring bycatch at the species and system level EA suggests that the results of the survey be used to investigate the sustainability of current bycatch levels, with the long-term aim of developing reference points to trigger management responses.

An indicator group of bycatch species has not been identified due to the very low bycatch in this fishery. In the event that bycatch levels increase and an indicator group becomes apparent EA expects that appropriate management responses will be developed in a timely manner.

Conclusion

Following analysis of the submission, supporting documents and other relevant information EA considers that the Queensland Spanner Crab Fishery meets Objective 1 and is conducted in a manner that does not threaten bycatch species. Current bycatch levels are very low and the combination of gear type, fishing operation and lack of interaction with the environment beyond the target species provides confidence in the fishery's ability to maintain low bycatch levels.

Whilst quantitative bycatch information is collected through the Long Term Monitoring Program there is no mechanism by which to monitor bycatch by fishery-dependent means. Sound fishery-dependent information on bycatch would complement the fishery-independent data, help confirm the informal bycatch risk assessment, quantify bycatch at the species and system level and highlight any system or species changes in bycatch.

Recommendation

Develop an appropriate means of monitoring bycatch in the fishery in addition to the Long Term Monitoring Program.

Objective 2: The fishery is conducted in a manner that avoids mortality of, or injuries to, endangered, threatened or protected species and avoids or minimises impacts on threatened ecological communities.

Information requirements

Direct observation of interactions with protected species is the only information source cited by QFS. The submission indicates that there have been occasional (rare) interactions with loggerhead turtles (Caretta caretta) in the fishery, eg entanglement of flipper in float-line, without any injury to the animals. Occurrences of such interactions are reported to be extremely rare.
Loggerhead turtles are listed endangered, migratory and marine species under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and as such any interaction with the species must be examined.

Provision for the inclusion of reporting on protected species interactions in logbooks is stated to be under consideration by CrabMAC. EA strongly recommends the establishment of a reporting mechanism for protected species interactions to increase reliability of current information and provide a mechanism by which monitoring of interactions can occur. A protocol for reporting of interactions to EA as required under the EPBC Act should also be developed.

There are currently no threatened ecological communities identified in the fishery area, consequently no information collection system or assessment is required.

Assessment

No formal assessment of impact of the fishery on protected species is undertaken however the submission explains that the risk of impact is considered very low due to dilly design and operation. EA concurs with this assessment, however reports of turtle interactions raised concerns.

The issue of turtle captures in the fishery, specifically the capture of loggerhead turtles was raised as an issue during the public comment period. The public comment cited research undertaken by the Queensland Parks and Wildlife Service (QPWS) that reports that a total of 48 turtles (loggerhead turtles and other species) were captured by fishing operations (including crab fisheries) since 1987 in the area. This raised the concern about the potential risk of incidental mortality of turtles in the Spanner Crab Fishery.

EA sought clarification of these reports and examined the research cited by the public submission and other related research papers. Information provided to EA from QPWS concluded that whilst there are records of loggerhead turtles (and other species) becoming caught or entangled in crab pots and float lines there are no records linked directly to the spanner crab fishery or the dillies used. All records cite crab pots, with no mention of crab dillies, which are significantly different in design and structure and unlikely to capture turtles. Analysis of recent QPWS annual reports of marine turtle stranding and mortality (Haines et al, 1999; Haines and Limpus, 2000) revealed no direct links of turtle mortality or interaction to the spanner crab fishery.

EA also sought confirmation of this report from turtle expert Dr Colin Limpus of the Queensland Parks and Wildlife Service. It was confirmed that reports cited in the public comment did not refer to spanner crab operations but to inshore crab operations in the area. There are no formal records of the capture or entanglement of loggerhead turtles in the spanner crab fishery. There are however, anecdotal reports (letters and verbal reports) of loggerhead turtles being shot and clubbed by operators in the spanner crab fishery. These reports date back a number of years, with no recent reports received and all evidence supporting them is circumstantial. Loggerhead turtles have been found washed up on beaches with bullet holes in their skulls, and others with fractured skulls, indicative of being clubbed (Dr Limpus - pers. comm). There is also evidence that loggerhead turtles feed on spanner crabs. Dr Limpus notes that there is no empirical evidence or first hand observation to conclusively say that these activities occurred in the spanner crab fishery or that this activity is ongoing.

Given the unfavourable conservation status of loggerhead turtles these reports are extremely disturbing and if true, could threaten any future recovery of the species. However, as these reports relate to the illegal behaviour of individual fishers and given the lack of hard evidence to support these reports, there are no management arrangements available to solve the problem. In recognition of the conservation status of the species and the need to take all reasonable steps to mitigate impact on protected species it is recommended that QFS undertake to increase fishers' awareness about protected species and instigate the reporting of protected species interactions in the daily logbooks. These suggestions should not be an onerous task. EA understands that steps have already been taken to include protected species reporting in the logbooks, and there is currently an Endangered and Threatened Species Awareness Course undertaken by all new trainees to the fishery, which could be made compulsory for all operators in the fishery.

EA recognises that this issue is to a large extent beyond the control of the fishery managers and is not related to the management arrangements currently in place for the fishery but believes these suggestions ensure that the risk to protected species is managed in the most effective way.

Management response

The lightweight design, structure, deployment and use of the spanner crab dilly results in little interaction with protected species. The current dilly design is clearly prescribed in the management plan and the submission indicates that there are no plans to modify its design in the near future. Whilst there are currently no trigger points for managing and monitoring impacts on protected species and communities the current design and deployment of the gear used is sufficiently benign and interactions with protected species is extremely low.

EA understands that there is voluntary use of weighted ropes and trotlines in the fishery to ensure minimal rope is in the water columns for potential entanglement by other species. EA considers this a proactive initiative and welcomes its uptake across the fishery. The submission also refers to the Endangered and Threatened Species Awareness Course that all new trainees must complete. EA suggests this could be used as a useful platform for the education of all fishers operating in the fishery, in particular with respect to the issue of turtle shooting and clubbing.

Conclusion

Overall the risk of the fishery impacting on protected species and ecological communities is very low and the fishery operates in accordance with Objective 2. The reports of turtle shooting and clubbing are not substantiated by hard evidence, are the results of actions of individual fishers and are beyond the control of the fishery management arrangements. EA considers that the Queensland Spanner Crab Fishery operates in a manner that avoids mortality of, or injuries to, endangered, threatened or protected species and avoids or minimises the impacts on threatened ecological communities. The recommendation, which includes logbook reporting of species interactions and increased fisher education, will enhance the fishery's ability to monitor impact on protected species and increase awareness about the potential impact of the fishery on theses species.
As there are no ecological communities identified in the fishery area the development of an information collection system, risk assessment and management arrangements are not required. EA understands that should such a community be identified, QFS will take appropriate management action in a timely manner.

Recommendation

Establish a reporting mechanism for protected species interactions, including the development of a protocol for reporting of interactions of protected marine species to EA as required under the Environment Protection Biodiversity Conservation Act 1999, and the development of a program to educate fishers about protected species. If it is revealed that interactions occur more frequently than previously thought, mitigation measures, including trigger and reference points, should be introduced to reduce interactions.

Objective 3: The fishery is conducted, in a manner that minimises the impact of fishing operations on the ecosystem generally.

Information requirements

There has been no formal information collection system dedicated to determining the impact of the fishery on the ecosystem or broader environment. The submission indicates that the bycatch data to be collected as part of the Long Term Monitoring Project may provide information needed to assess ecosystem impact. In recognising the nature of spanner crab habitat (flat sandy bottom), the low levels of bycatch, and the non-intrusive nature of the fishing gear, the collection of ecosystem impact data has not been a priority. EA concurs with the argument presented by QFS and is satisfied with its conclusion.

Assessment

No formal assessment of the impact on the ecosystem components has been undertaken however the submission provides an informative analysis of the potential impacts. The submission indicates that impact is considered minimal but clearly recognises areas of uncertainty, in particular the role of spanner crabs in their ecosystem.

In its assessment of the risks the submission states that the ecological impact of the fishery on the biotic component of the ecosystem is likely to be confined to the effects of harvesting due to the selective removal of the predatory crabs. Little is known about the ecological relationships between spanner crabs and other species. There is a poor understanding of the food chains and predator-prey relationships operating in the fishery area.

The submission identifies the removal of the target species and its impact on the size of the spawning stock and food chain as the most serious risk. Whilst the exact nature of the predator-prey relationships operating in the area is largely unknown, EA believes that the current level of removal of spanner crabs by the fishery, and its management arrangements, are precautionary and the adaptive management arrangements ensure that the level of take from the fishery can be controlled. In light of this information, predator-prey relationships may not be drastically altered as a result of spanner crab fishing alone. However, the lack of understanding of these relationships needs to be fully explored before such a conclusion can be drawn. The need for information on these relationships is identified by QFS. Some predator species are mentioned (sharks, rays, turtles) that may rely (to some extent) on spanner crabs. The diet of spanner crabs is largely unknown. EA recommends ongoing monitoring of bycatch and investigation of food web relationships.

The impact of the fishery on benthic communities and physical habitat is considered minimal due to gear design and deployment methods. The dilly is lightweight, does not move significant distances along the sea floor and is deployed on sandy substrate.
The impact of the fishery on water column communities is not an area of concern given the demersal nature of the fishery. The fishery has minimal impact on water quality as processing of catch is not conducted on board and the discard of biological waste is minimal.

The impact of careless removal of undersized crabs is identified as a potential risk to the long-term levels of recruitment into the harvestable component of the fishery. QFS reported that a change to management arrangements (ie a move to an ITQ system) minimised the need for fishers to clear large numbers of dillies quickly and has provided a stock stewardship sentiment amongst many fishers. Further analysis of this problem is currently under investigation through the Dilly Review that will consider modifications to the dilly design to minimise this risk. EA is interested in the results of the dilly review and the implications of such results for the future management of the fishery.

Management response

In the absence of significant impact of the fishery on the ecosystem, management arrangements have not been developed. The submission indicates that should a threat to the ecosystem be identified appropriate management responses and trigger points will be developed. EA considers this a reasonable approach and encourages collection of information on the ecosystem impacts of the fishery and the timely development of appropriate actions should significant impacts be identified.

Conclusion

Given the relatively benign impact of the fishing gear on the physical environment the only risk to the ecosystem appears to be a lack of understanding of food chain relationships and the subsequent impact on predator prey relationships. This is not considered a high risk when considering the current management arrangements capacity to limit stock harvest and maintain stock biomass. In considering the low bycatch levels, minimal interaction with protected species and benign impact on the physical environment, EA considers the fishery meets Objective 3 and is conducted in a manner that minimises the impact of fishing operations on the ecosystem generally.

The range of information needs identified in the submission is a positive step towards obtaining more information on the impact of the fishery on the environment. EA encourages further information collection with a view to undertaking a formal risk assessment of the ecological impact of the fishery to confirm the current assumption that ecosystem impacts are low.

Recommendation

Undertake a formal risk assessment of the ecological impact of the fishery on predator prey relationships before the next assessment to confirm assumptions that the broad ecosystem effects of the fishery are low.

References

Haines, J. A., Limpus, C. J. and Flakus, S. (1999) Marine wildlife stranding and mortality database annual report, 1999 - III Marine turtles. Queensland Parks and Wildlife Service.

Haines, J. A. and Limpus, C. J. (2000) Marine wildlife stranding and mortality database annual report, 2000 - III Marine turtles. Queensland Parks and Wildlife Service.