Microsatellite genetic variation within and among Arctic charr ( Salvelinus alpinus) from aquaculture and natural populations in North America

Abstract

The amount of genetic variation in aquaculture strains of North American Arctic charr ( Salvelinus alpinus) originating from the Fraser River (Labrador), Nauyuk Lake and Tree River (Nunavut), and Lake Aleknagik (Alaska) was compared to that in natural populations using six microsatellite markers. Aquaculture strains originating from Nauyuk Lake and Tree River had less genetic variability than their wild source populations in terms of allelic diversity, but not necessarily in observed heterozygosity. In aquaculture strains, the average number of alleles is positively associated with the number of fish used to produce each strain. Pairwise tests for genetic differentiation between populations were significant for all but three comparisons. These comparisons consisted of consecutive year classes of cultured Labrador and Nauyuk fish originating from the same wild collections. A neighbour joining tree grouped samples according to their geographic origin. These results indicate that hatchery strains and natural populations of Arctic charr are genetically differentiated and that small founding population sizes have contributed to reduced genetic variation in aquaculture strains. This genetic survey is intended as a baseline for future genetic monitoring of Arctic charr aquaculture strains and will aid in the development of breeding programs for production and management.