Genetic Characterization of Bull Trout from the Asotin and North Fork Wenaha River Basins

Collections of bull trout from the upper and lower Asotin Creek were analyzed to determine the relationship between these areas within the Asotin Creek. Bull trout samples from the North Fork Wenaha River, Walla Walla River basin and Tucannon River were also compared to the samples from the Asotin Creek. Sixteen nuclear microsatellite DNA loci that are included in the standardized suite of loci were used to examine the levels and patterns of genetic variation. Tests of population subdivision, factorial correspondence analysis, and the neighbor-joining tree suggested the collections of bull trout from the upper and lower Asotin Creek are genetically differentiated; however there are some samples from the upper Asotin Creek that appear in the lower Asotin Creek. Bull trout in both the upper and lower Asotin Creek are differentiated from samples of bull trout in the North Fork Wenaha River, the Walla Walla River basin, and the Tucannon River. Bull trout from the North Fork Wenaha were different than bull trout in both Asotin Creek and the Tucannon River.