Sustainability of the rock lobster resource in south-eastern Australia in a changing environment: implications for assessment and management
Department of Economic Development Jobs Transport and Resources (DEDJTR)
1. Undertake initial evaluation of catch and effort data for a selection of vessels (or skippers) for CPUE standardisation and undertake spatial analysis of rock lobster to depict annual CPUE trends within discrete regions standardised for effects of vessel (or skipper), season, and spatial cell defined by grid-cell and depth range.
2. Extend CPUE analyses to test for and standardise for, where feasible, the effects of oceanographic variables such as bottom temperature, dissolved oxygen, currents, and wave strength using available data from the Bonney Coast and then test the applicability of these results to western Tasmania and determine additional data requirements for extending the analyses to this region.
3. Apply various analyses such as within-season depletion models and each State’s stock assessment models using available catch and effort data, other monitoring data, and tag release-recapture data to explore variation in annual estimates of catchability and recruitment through time.
4. Investigate evidence for temporal trends in lobster recruitment across the three States, examine evidence of a declining trend since 2003, and examine relationships between yearly environmental signals, and the yearly puerulus index to yearly environmental signals.
5. Undertake growth analyses of available tag release-recapture data to explore variation in annual estimates of growth through time.
6. Undertake stock assessment modelling to explore the sensitivity of biomass projections to altered values of catchability, recruitment, and growth, and, if necessary, make appropriate corrections to components of the stock assessment models.
7. Undertake management strategy evaluation, testing stock assessments and exploring implications of alternative assumptions for catchability, recruitment, and growth.