Reduced Genetic Variability in First-Generation Hatchery Populations of Atlantic Salmon (Salmo salar)

Levels of genetic variation were measured in first-generation Atlantic salmon (Salmo salar) cultured for stock enhancement programs in eastern Canada and compared with variation in wild stocks. One regulatory and 19 structural protein loci were screened of which 10 were polymorphic. Mean heterozygosity and number of alleles per locus were positively correlated with the effective number of adults (N) used to establish the hatchery groups and averaged 26 and 12% lower, respectively, than wild stocks. The observations are consistent with a loss of genetic variability in the hatchery salmon from random drift caused by using small numbers of salmon for broodstock.