THE GENETIC DIVERSITY OF NATIVE, STOCKED, AND HYBRID POPULATIONS OF BROOK TROUT IN THE SOUTHERN APPALACHIANS

Using mitochondrial DNA (mtDNA) restriction analysis and starch-gel el ectrophoresis of the CK-A2 locus product, we examined genetic variatio n in 311 brook trout (Salvelinus fontinalis) from 11 native, 5 hatcher y-derived, and 8 hybrid populations in the southern Appalachian Mounta ins. Native southern Appalachian fish were genetically distinct from h atchery-derived fish. Southern and hatchery-derived fish were reliably distinguished based on three mtDNA restriction sites. Native southern haplotypes differed from hatchery-derived haplotypes by an average of 0.84%. Northern hatchery-derived haplotypes varied little in mtDNA co mpared to native southern haplotypes. Introgression of mtDNA haplotype s and the CK-A2 locus varied among populations, and introgression of a llozyme and mtDNA markers was positively correlated. Continued introdu ctions of nonnative strains of brook trout in the southern Appalachian s could simplify the genetic structure of native brook trout populatio ns and eliminate unique genotypes.