Mesoscale oceanographic features drive divergent patterns in connectivity for co?occurring estuarine portunid crabs

Larval dispersal and connectivity have important implications for fisheries management, especially species with life cycles influenced by ocean boundary currents. Giant Mud Crab (Scylla serrata) Blue Swimmer (Portunus armatus) are two estuarine portunid crabs (Family: Portunidae) that support significant commercial recreational harvest in eastern Australia. migrate to coastal waters spawn, while spawn primarily within estuaries they occasionally followed larval the East Australian Current (EAC). Here, we coupled a high-resolution oceanographic model Lagrangian particle tracking framework simulate determine extent of population this region. Our simulations indicate broad-scale (~40–400 km), characterised high inter-estuary connectivity. Overall, our results suggest north-to-south source-sink structure both species, contributions particles from north ranging 51% 99%. Recruitment given estuary is dependent on proximity mesoscale features EAC. Most notably, EAC separation acts as barrier recruitment between spawning settlement north/south This significantly limits interjurisdictional these Crab, likely due shorter pelagic duration than Crab. provide evidence inform assessment management species.