Genetic variation and stock structure of school mackerel and spotted mackerel in northern Australian waters

The total mean sample heterozygosity calculated from eight polymorphic loci was 0.172 (0.047 S.E.) (F(st) 0-025) for school mackerel Scomberomorus queenslandicus, and for spotted mackerel S. munroi was 0.110 (0.074 S.E.) (F(st) 0.038). There was no evidence of temporal variation for either species as significant genetic differences were not detected between months or year classes within areas. Spatially, school mackerel have a complex stock structure, with stocks being associated with large embayments. In contrast, spotted mackerel appear to comprise a single stock in Australian east coast waters. Both species showed a significant pattern of stock structure between Australian east coast and northern (Arafura Sea) samples