The ability of fisheries managers to control for sustainable harvest and reduce risks of fisheries overexploitation depends largely on an understanding of biological stock structure and recruitment dynamics. This information is critical for understanding the resilience of individual fishing stocks to fishing pressure and environmental disturbance, and the potential for stock replenishment through natural recruitment processes. At present this information is lacking for Australian giant crab (P. gigas) and giant spider crab (L. gaimardii) fisheries.

New opportunities have emerged that greatly enhance our ability to characterise patterns of biological stock structure in fine detail. Modern genomic technologies now allow for rapid and cost-effective assessments of genome wide variation within and between natural populations, allowing for spatial patterns of genetic structure to be characterised with unprecedented sensitivity. Additionally, advances in modelling capabilities are now allowing the unique integration of biological and physical oceanographic data to develop high-resolution models of larval dispersal in complex marine environments. Combining these new tools with traditional methods, such as stable isotopes and acoustic telemetry, provides a unique opportunity to undertake better assessments of biological stock structure and dynamics by accounting for both adult and juvenile dispersal stages.

Our team will leverage existing partnerships with industry stakeholders to undertake a comprehensive assessment of biological stock structure in the P. gigas and L. gaimardii fisheries. We proposed to adopt a multidisciplinary research program that will help to define the geographic boundaries of biological populations and the recruitment potential of individual fishing stocks. Outputs from this project will provide managers with a resource for establishing sustainable management programs in these fisheries that account for patterns of stock connectivity and the sensitivities of individual stocks to environmental disturbance and fishing pressure.

AVG remains the greatest threat to the economic viability and stability of the abalone industry in south-eastern Australia. As a consequence, there is an urgent need for strategic research aimed at determining the likely vulnerability of fisheries to future AVG outbreaks and providing managers with the necessary tools for biosecuring wild and farmed stocks at regional, state and national scales.

The fact that some animals from AVG affected wild stocks survived the disease outbreak suggests they were either fortunate enough to have avoided coming into contact with the virus or are genetically resistant to the disease. A research program aimed at characterising AVG resistance in Australian wild abalone fisheries is expected to provide benefits to wild and farm fisheries at a national scale. If AVG resistance is present in wild abalone stocks, and its genetic basis can be characterised, there will be unique opportunities to:

1) Rapidly and cost-effectively screen stocks across all wild fisheries to determine the spatial prevalence of resistant genotypes and to gain an understanding of how biosecure wild abalone stocks are likely to be in the event of AVG re-emergence
2) Biosecure wild stocks through the movement of animals from ‘AVG resistant’ to ‘AVG vulnerable’ stocks as part of future restocking and translocation activities
3) Biosecure farm stocks across all states of Australia through the establishment of an AVG resistance breeding program

This project involves a direct partnership with AAGA, ACA and VFA and is expected to provide much needed insights into the vulnerability of abalone stocks to future AVG outbreaks, and the tools needed to bolster the biosecurity of wild and farmed abalone stocks. As a result, this project has the potential to dramatically improve the economic viability of this rapidly expanding industry.