The research program supported by this grant was directed at determining the number and distribution of subpopulations or genetic stocks which contribute to Australian fisheries for barramundi, northern sharks, and narrow-barred Spanish mackerel. Starch gel electrophoresis was used to reveal patterns of genetic variation in each species.

The analysis of approximately 4,500 barramundi collected at locations from the Ord River in Western Australia to the Rockhampton area of Queensland revealed the existence of at least 14 genetically discrete stocks. The significant amount of genetic subdivision characterizing Australian barramundi indicates that fisheries regulations and management policies must be focused on individual barramundi stocks in order to be maximally effective. The number and location of reserves, possible stocking of hatchery reared fish, and selective breeding of captive barramundi should all be based upon maintaining and exploiting the naturally occurring genetic heterogeneity of barramundi populations indicated by this study.