Genetic parameters of pink salmon introduced into the White Sea basin in 1985 and 1998 were compared to the corresponding parameters of the donor population from the Ola River (Magadan oblast). The detected genetic differences indicate that colonization of a new area is accompanied by impoverishment of the gene pool of the native population. This effect was particularly marked in the odd-year line of pink salmon introduced in 1985. The probable causes of these genetic changes are discussed.