Stock assessment of the EKP fishery, and the subsequent advice to management and industry, could be improved by addressing a number of issues.

The recruitment dynamics of EKPs in the northern (i.e., North Reef to the Swain Reefs) parts of the fishery need to be clarified. Fishers report that the size of the prawns from these areas when they recruit to the fishing grounds is resulting in sub-optimal sizes/ages at first capture, and therefore localised growth overfishing.

There is a need to assess alternative harvest strategies of the EKP fishery, via computer simulations, particularly seasonal and monthly or lunar-based closures to identify scenarios that improve the value of the catch, decrease costs and reduce the risk of overfishing, prior to implementing new management measures.

The project is highly relevant to FRDC priorities and directly addresses the FRDC R&D 2005-2010 Plan, namely Program 1 Natural Resources Sustainability, Challenge 1 – Natural Resource Sustainability “Maintain and improve the management and use of aquatic natural resources to ensure their sustainability”.

The proposal directly addresses the QFIRAC 2007 R&D priorities for Trawl Fisheries which specifically refer to “Undertaking management strategy evaluations for the Eastern King Prawn fishery, particularly the potential for seasonal closures…”.

It also addresses the Queensland TrawlMAC “high” research priorities in relation to improving our understanding of the stock-recruitment relationships and undertaking management strategy evaluations.

In summary, there is a strong need for this project, which addresses the high research priorities identified by FRDC, QFIRAC and the Queensland TrawlMAC. It is focused on Queensland’s most valuable fished stock, eastern king prawns.

Need for trawl mapping
Information on where trawling does and does not occur is needed by fishery managers, industry, GBRMPA and others to inform debate and decision making for the trawl fishery. By June 2002, VMS will have recorded all Queensland trawl effort (except the Moreton Bay fishery) every hour for 18 months. These data can be used to map the distribution and intensity of trawling better than ever before. These maps are required by July 2003 for implementation of the Queensland Trawl Plan. Such maps are also needed to model the ecological effects of trawling, since untrawled areas may provide refuge for some vulnerable bycatch species. Such maps will also help assess the required 40% reduction in bycatch.

Need to develop stock assessment and management for ESD
The Trawl MAC have named stock assessment and Review Events as their top research priorities, and VMS research as a high priority. There is a need to improve abundance indices, currently based on CPUE from trawl shots defined as square CFISH grids (6’ by 6’ or 30’ by 30’). This is unrealistic and can lead to significant errors in stock assessment. There is also a need to investigate the way targeting and depletion of aggregations interact with economic factors to affect CPUE.

We can meet these needs using effort and density indices at fine spatial and temporal scales, by using the functionality of newly developed commercial software to develop our modelling systems. Matrices of stock abundance in space and time can be mapped (see attached map) or used in stock assessment models. A major area of research need with the OceanFARM software is user definition of trawl signature and catch distribution functions, which differ between sectors of the trawl fishery.

The functionality must be integrated into the overall management and assessment strategy for each fishing sector. There is potential to substantially improve the reliability of stock assessments.