WAMSI Node 4.4.2-2a - Genetic (microsatellite) determination of the stock structures of West Australian dhufish in Western Australian waters and hydrodynamic dispersal modelling

Determining the extent of dispersal in exploited marine fishes is essential for understanding their population dynamics and optimising management. The West Australian dhufish, Glaucosoma hebraicum, is a sought-after, large and long-lived reef-dwelling species, endemic to south-western Australia. We analysed 13 microsatellite loci to characterise the extent of gene flow, and conducted particle tracking simulations to model larval transport in this species. Genetic data demonstrated that some local recruitment was likely, but that on a broad scale gene flow between the management zones was extensive, and the entire fishery represents a single genetic stock. In contrast, hydrodynamic modelling predicted that the majority of dhufish larvae recruit from within the management zone where they are spawned, and that inter-annual variation in current velocities has little effect on the extent of larval transport. The existing management zones are likely to be largely independent in terms of both larval and adult recruitment.