Most jurisdictions have developed and used various combinations of indicators in stock assessment and TAC setting of their abalone fishery. Applications often use a time series of commercial catch rate or FIS density to detect trends and identify reference points of stock status. The use of fishery dependent indicators from logbooks and GPS loggers have been criticized for their potential to be biased and insensitive (‘hyper-stable’) because of commercial selection of all observations that are made. As a consequence, Fishery Independent Surveys (FIS) have also been used in stock assessment, with varying coverage in all state’s abalone fisheries. However, FIS have also been criticized for their large cost and considerable uncertainty about how representative and useful the data is for intensely spatially-structured abalone fisheries (e.g. spatial mismatch of the FIS and the stock). FIS reviews in several states found variable relationships between FIS estimates and other indicators of the fishery.

Alternatively, both GPS loggers and FIS have considerable complementary strengths. GPS logger information has strengths of extensive fine-scale detail about catch (e.g. allowing spatial standardisation, that represents one of the main challenges to fishery dependent data) with good coverage of the fishery, while FIS have strengths of repeatable and local scale detail that is independent of the fishery.

The project will review data available from GPS loggers, catch records and FIS in WZ Victoria, with possible extension to other fisheries depending on data access and funding. Methods to calculate density and biomass from different sources of data will be consolidated and applied at different spatial scales, and the precision and statistical coherence of estimates compared. These comparisons will enable the development of criteria to improve design of FIS, logger programs and related observations, and recommendations and guidance on the use of indicators of legal density and biomass in fishery harvest strategies.