The complex problems involved in managing Pacific salmon are largely a consequence of the unusual life history features of these species. The strong homing instinct leads to the formation of discrete, locally adapted spawning populations, each of which has the potential to evolve as an independent evolutionary unit. It is important, therefore, that the genetic consequences of different management policies be carefully evaluated. If current management goals (e.g. doubling the abundance of anadromous salmonids in the Columbia River basin through increased hatchery production and supplementation of natural populations) are realized, genetic issues will assume even greater importance in the future. To date, however, genetic concerns have not been adequately incorporated into the management process... The ability to detect hybridization and introgression is necessary for an evaluation of the genetic consequences of releasing artificially propagated fish into the wild.