Stock assessment of blue swimmer crab (Portunus armatus), Queensland, Australia, with data to June 2024

Abstract

This report informs on the status of the north-eastern Australia (Queensland east coast) blue swimmer crab biological stock through estimates of exploitable (legal sized male crab) and spawning biomass (mature female crab). The estimated exploitable biomass of blue swimmer crab in fishing year 2023–2024 was approximately 30 percent of unfished biomass. The estimated spawning biomass in 2023–2024 was about 47 percent.
This was the third assessment of Queensland blue swimmer crab. The model accounted for separate female and male populations, seasonality, fishing sectors, and recruitment variability. Twelve alternative data scenarios were evaluated and combined in an ensemble of model simulations. Key inputs were total harvest and discard mortality, standardised catch rates from commercial, recreational and fishery-independent surveys, and size-frequency data from commercial pot and trawl fisheries.