Persistence of Native Southern Appalachian Brook Trout Populations in the Pigeon River System, North Carolina

The range of brook trout Salvelinus fontinalis in the southern Appalachian Mountains has been greatly reduced by environmental disturbance and introduction of rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta. In addition, hatchery-reared brook trout originating from northern populations have been widely stocked in the region's streams. To an undetermined extent northern brook trout have established themselves or interbred with the genetically distinct native Southern Appalachian strain. Genetic analyses have been performed on a portion of North Carolina's wild brook trout populations to identify those of unaltered native origin. However, information for many streams is lacking, and an assessment of the relative abundance or rarity of genetically unaltered native populations cannot yet be made. The objective of this project was to determine the phylogenetic origin of brook trout in 23 streams within the Pigeon River system, Haywood County, North Carolina. Fish were collected by electroshocking, and muscle tissue samples were obtained by nonlethal biopsy. The samples were analyzed by cellulose acetate gel protein electrophoresis for loci encoding creatine kinase and up to five additional enzymes. Allele frequencies for these enzymes indicated that 15 of the populations were of unaltered native Southern Appalachian origin, 2 were of hatchery-derived northern origin, and 6 were of mixed genetic origin. This information has been incorporated into a North Carolina Wildlife Resources Commission trout species distribution database used in refining stream and fisheries management policies.