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• Main Author: J. E. Graves
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: highly migratory; intra-season variation; microsatellites; mixed stock; teleost; Thunnus thynnus; Norway; Iceland; Northeast Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.491.8538; http://www.vims.edu/people/graves_je/pubs/jeg_Carlsson_et_al_2006.pdf

17 th as o bluefin tuna caught in the northeast Atlantic south of Norway suggested mixing of putative stocks in the region, based on abrupt shifts in the size and condition of fish during the fish-ICES Journal of Marine Science, 63: 1111e1117 (2006)ing season. By contrast, more recent studies south of Iceland reported only small differences in size of tuna caught at different times of the season in that area. To better understand the stock structure and composition of Atlantic bluefin tuna in the region, we surveyed genetic variation at eight microsatellite loci for 800 Atlantic bluefin tuna collected in experimental commercial fishing operations south of Iceland during 1999 and 2002. We tested for hetero-geneity between years, between seasons within a year, between two fishing areas within the region, and between sexes. Analysis of molecular variation demonstrated slight, but signif-icant, genetic divergence between collections of fish caught early and late in the season over the two years. These results are consistent with prior observations of Atlantic bluefin tuna of different conditions entering the fishery through the season, and suggest that the northeast Atlantic fishery represents a mixed-stock fishery including animals migrating from different areas and recruited from different spawning grounds.