Genetic mixed stock analysis of an interceptory Atlantic salmonfishery in the Northwest Atlantic

Authors

Ian R. Bradbury, Science Branch, Fisheries and Oceans CanadaFollow
Lorraine C. Hamilton, Bedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, Halifax, Nova Scotia
Gerald Chaput, Centre for Science Advice, Gulf Region, Fisheries and Oceans Canada, Moncton, New Brunswick
Martha J. Robertson, Science Branch, Fisheries and Oceans Canada
Herlé Goraguer, Ifremer, Saint Pierre et Miquelon, France
Arthur Walsh, Science Branch, Fisheries and Oceans Canada
Vicki Morris, Science Branch, Fisheries and Oceans Canada
David Reddin, Science Branch, Fisheries and Oceans Canada
J. Brian Dempson, Science Branch, Fisheries and Oceans Canada
Timothy F. Sheehan, NOAA Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA
Timothy King, United States Geological Survey, Leetown Science Center, Kearneysville, WV
Louis Bernatchez, Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada

Date of this Version

2016

Citation

Fisheries Research 174 (2016) 234–244

Comments

U.S. Government Work

Abstract

Interceptory fisheries represent an ongoing threat to migratory fish stocks particularly when managed in the absence of stock specific catch and exploitation information. Atlantic salmon from the southern portion of the North American range may be subject to exploitation in the commercial and recreational salmon fisheries occurring in the French territorial waters surrounding St. Pierre and Miquelon off southern 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 a microsatellite baseline (15 loci, 12,409 individuals, 12 regional groups) encompassing the species western Atlantic range. Individual salmon were sampled from the St. Pierre and Miquelon fishery over four years (2004, 2011, 2013, and 2014). Biological characteristics indicate significant variation among years in the size and age distribution. Nonetheless, estimates of stock composition of the samples showed consistent 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 the decade examined. Comparison of individual assignments and biological characteristics revealed a trend of declining fresh water age with latitude of assigned region. Moreover, locally harvested Newfoundland salmon were ten times more likely to be small or one sea winter individuals whereas Quebec and Gaspe Peninsula 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 region ranging from 242 to 887 individuals annually. This work illustrates how genetic analysis of interceptory marine fisheries can directly inform assessment and management efforts in highly migratory marines pecies.