Genetic Mixed Stock Analysis of Three Northwest Atlantic Salmon Fisheries

We evaluated stock composition of Atlantic salmon harvested in three fisheries in the northwest Atlantic using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 12409 individuals, 12 groups) encompassing the species western Atlantic range. 353 individuals collected from the Saint Pierre and Miquelon fishery (2004, 2011-2014) were analyzed and estimates of stock composition showed consistent dominance of three regions, Gulf of St. Lawrence, Gaspe Peninsula, and Newfoundland.  In the West Greenland harvest (2011-2014, n=2336) North American contributions were largely from Labrador, the Gulf of St. Lawrence, and the Gaspe Peninsula.  No evidence of spatial or temporal trends in mixture composition was apparent in the fishery.  Finally in the coastal Labrador fishery (2012-2014, n=771) mixture estimates suggest the harvest is dominated by a single region, central Labrador (95.3%).  Minor components were also allocated to Northern Labrador / Ungava and Newfoundland (<4%). In all three fisheries, estimates of stock composition appear stable over time and assigned individuals show the expected trend of declining river age with latitude of home region. This work illustrates how genetic analysis of these mixed stock Atlantic salmon fisheries in the northwest Atlantic can directly inform assessment and management efforts in the region.