Natural hybridization between steelhead trout (Salmo gairdneri) and coastal cutthroat trout (Salmo clarki clarki) in two Puget Sound streams
Campton, DE.; Utter, FM.
Canadian Journal of Fisheries and Aquatic Sciences 421: 110-119
ISSN/ISBN: 0706-652X DOI: 10.1139/f85-014
A genetic investigation of anadromous trout populations in Puget Sound, USA, revealed in 2 streams many juveniles with electrophoretic phenotypes consistent with those expected for hybrid descendents of steelhead trout (Salmo gairdneri) and coastal cutthroat trout (S. clarki clarki). The likelihood of hybridization was evaluated with a hybrid index measuring the relative probability that the combined genotype for a particular fish at several diagnostic loci could have arisen by random mating within each of the 2 Salmo species. The distribution of hybrid index scores among fish from the 2 creeks demonstrated the genetic distinctness of the 2 species and the intermediate genotypic composition of the unknown fish.