The Stock Structure of Northern and Western Australian Spanish Mackerel

Abstract

Decisions about the allocation of management responsibilities for fisheries for narrow-barred Spanish mackerel, Scomberomorus commerson, as well as on-going stock assessments, require an understanding of the spatial relationships of the species. We used a suite of methods, isotope ratios in otoliths (earbones), parasite abundances, and genetic analyses (allozyme, mitochondrial DNA (mtDNA), and microsatellite DNA (msDNA) methods), to examine the spatial stock structure of Spanish mackerel. Fish were sampled from across northern Australia, and from Kupang (Indonesia). Project objectives included describing stock structure of the northern Australian stock of Spanish mackerel, advising on the appropriate scale of assessment and management for the stock, and comparison with material from Kupang (West Timor, Indonesia).