Stock assessments are an essential part of sustainable fisheries practices that not only safeguard the environment, but the industry as well. Natural resources sustainability is the most important of four programs outlined in FRDC’s new research and development plan for 2000 and beyond. Research on stock assessment methods is one of ten strategies outlined in the sustainability program. Our project, that aims to validate an innovative and economical addition to stock assessment methods, is a practical way to achieve one of FRDC’s strategic goals.

Stock assessment is hugely important, but is also very expensive and has a critical need for improved accuracy and precision. The Research and Environment Committee of NORMAC estimates that stock assessment of the northern prawn fishery costs over $700,000 per year. The refinements proposed to stock assessment methodology as a result of this project may significantly reduce these costs, perhaps down to $100 -200,000 per year for both species of Gulf tiger prawns.

This new methodology also has the potential to increase the accuracy and precision of stock assessment estimates. As it stands, stock assessment methodology is widely recognised to have serious limitations. Catch and effort data is used as a surrogate for biomass but is known to be biased due to the aggregation behaviour of both the fishing fleet and target species. The common assumption of a relationship between spawning stock size and subsequent recruitment is dogma that has never been rigorously tested. The great strength of this project is that genetic estimates of spawning stock size will be made that are completely independent of equivalent conventional estimates.