Genetic mixed stock analysis of an interceptory Atlantic salmon fishery in the Northwest Atlantic
tInterceptory fisheries represent an ongoing threat to migratory fish stocks particularly when managed inthe absence of stock specific catch and exploitation information. Atlantic salmon from the southern por-tion of the North American range may be subject to exploitation in the commercial and recreationalsalmon fisheries occurring in the French territorial waters surrounding St. Pierre and Miquelon offsouthern Newfoundland. We evaluated stock composition of Atlantic salmon harvested in the St. Pierreand Miquelon Atlantic salmon fishery using genetic mixture analysis and individual assignment with amicrosatellite baseline (15 loci, 12,409 individuals, 12 regional groups) encompassing the species west-ern Atlantic range. Individual salmon were sampled from the St. Pierre and Miquelon fishery over fouryears (2004, 2011, 2013, and 2014). Biological characteristics indicate significant variation among yearsin the size and age distribution. Nonetheless, estimates of stock composition of the samples showedconsistent dominance of three regions (i.e., Southern Gulf of St. Lawrence, Gaspe Peninsula, and New-foundland). Together salmon from these regions accounted for more than 70% of annual harvest over thedecade examined. Comparison of individual assignments and biological characteristics revealed a trendof declining fresh water age with latitude of assigned region. Moreover, locally harvested Newfoundlandsalmon were ten times more likely to be small or one sea winter individuals whereas Quebec and GaspePeninsula salmon were two-three times more likely to be harvested as large or two sea winter salmon.Estimates of region specific catch were highest for salmon from the southern Gulf of St. Lawrence regionranging from 242 to 887 individuals annually. This work illustrates how genetic analysis of interceptorymarine fisheries can directly inform assessment and management efforts in highly migratory marinespecies.