A microsatellite baseline for genetic stock identification of European Atlantic salmon (Salmo salar L.).

Atlantic salmon (Salmo salar L.) populations from different river origins mix in the North Atlantic during the marine life stage. To facilitate marine stock identification, we developed a genetic baseline covering the European component of the species’ range from the Russian River Megra in the north-east, the Icelandic Ellidaar in the west, and the Spanish Ulla in the south, spanning approximately 3700 km North to South and 2700 km East to West. The baseline encompasses data for 14 microsatellites for 26,822 individual fish from 13 countries, 282 rivers and 467 sampling sites. A hierarchy of regional genetic assignment units was defined using a combination of distance based and Bayesian clustering. At the top level subdivision is into Northern, Southern, and Icelandic regions. At the next level of regional subdivision where individual assignments could be accurately there are 18 geographical units and 29 units where accurate mixed stock estimates were possible. The baseline provides the most comprehensive geographical coverage for an Atlantic salmon genetic data-set, and a unique resource in the European marine fisheries context. It is freely available to researchers to facilitate identification of the natal origin of European salmon.