Oral Presentation Australian Society for Fish Biology Conference 2025

Filling knowledge gaps on Giant Mud Crabs (Scylla serrata) in Queensland (124383)

Julie Robins 1 , Nicole Flint 2 , Nick Stratford 3 , Samuel Seghers 3 , William Dantas Charles 2 , Matt Taylor 4 , Gabriella Scata 1 , Sam Williams 1
  1. Department of Primary Industries, Agri-Science Qld, Queensland Government, Dutton Park, QLD, Australia
  2. Central Queensland University, North Rockhampton, Qld, Australia
  3. Department of Primary Industries, Agri-Science Qld, Queensland Government, Cairns, Qld, Australia
  4. Department of Primary Industries and Regional Development (NSW), Nelson Bay, NSW, Australia

The Giant Mud Crab is an iconic and major fishery species in northern Australia, with approximately 65% of the Australian harvest coming from Queensland waters. Conservative management (male only harvest, 150 mm carapace width minimum legal size) has been a long-term strategy of this Queensland fishery, with an output control (a total allowable commercial catch) introduced in 2021.

Recent research (FRDC 2019-062) measured population parameters (e.g., genetic connectivity, size-at-maturity, reproductive seasonality, and female insemination rates) across multiple regions to inform the fishery’s Harvest Strategy.

Results indicated that there are small differences in regional biology, and that despite high fishing mortality on legal males in some regions, there is no strong evidence that this is a threat to the sustainability of Giant Mud Crab populations in Queensland. Results also indicated that most mature females were in their first mature intermoult and concurs with the paradigm that the offshore female spawning migration has likely high natural mortality, which may need consideration in jurisdictions where females are subject to harvest.