Natural Hybridization between Arctic Char (Salvelinus alpinus) and Lake Trout (S. namaycush) in the Canadian Arctic

Abstract

Natural interspecific hybrids between lake trout (Salvelinus namaycush) and Arctic char (S. alpinus) ranged in frequency from 1.8 to 6.8% in four of eleven lakes containing both species on the northern Melville Peninsula, N.W.T., and were also detected at several other sites across the Canadian Arctic. Hybrids were heterozygous for each of seven diagnostic allozyme loci between S. alpinus and S. namaycush, and were morphologically intermediate between the parental species. Restriction endonuclease analysis of mitochondrial DNA revealed that all but one of the hybrids had S. namaycush as their maternal parent. Resampling of two lakes where hybrids were detected revealed low levels of bidirectional nuclear introgression between the two species and limited transfer of S. namaycush mtDNA into S. alpinus.