Stock assessment of Queensland east coast blue swimmer crab (Portunus armatus)

Abstract

Blue swimmer crabs are widely distributed in Australia. They are found along the western coast of Australia, across Australia’s north and down the east coast to the New South Wales–Victoria border. This assessment of the north eastern Australian (Queensland) blue swimmer crab biological stock, informs the status of the stock and the harvest strategy development under Queensland’s Sustainable Fisheries Strategy.

This stock assessment used a length-structured model with a monthly time step. Data inputs included total harvests, standardised catch rates, and carapace width size compositions.

Model analyses suggested that exploitable (legal sized male) biomass fell to around 33 per cent of unfished biomass in 2018–19. The blue swimmer crab harvest control rule recommends an initial harvest limit of 129 t to begin rebuilding the stock to levels consistent with 60% of unfished biomass.