Stock structure of Spanish mackerel Scomberomorus commerson along the Australian east coast deduced from parasite data

Abstract

The parasite fauna of Spanish mackerel Scomberomorus commerson from three regions off eastern Australia was examined for evidence of separate stocks. The abundance of five metacestodes was very similar in all areas suggesting that extensive mixing of the fish occurs along the coast, unlike the situation across northern Australia where large differences have been found between regions. The similarity in abundances of two metacestodes from Townsville fish and south‐east Queensland fish suggests that these two regions have fish with very similar histories. The data lead to the conclusion that the seasonal fishery for Spanish mackerel off south‐east Queensland is based on a random group of fish from the same origin as fish sampled off Townsville and is not a subpopulation that moves south each year.