The Columbia River redband trout (Oncorhynchus mykiss gairdneri) is native to the Columbia River Basin east of the Cascades. The genetic structure of many redband trout populations has been influenced by introgression with hatchery stocks and by isolation due to migration barriers. Dry Creek is a tributary of the Boise River, characterized by large seasonal fluctuations in temperature and stream flow. The objective of our research was to continue a genetic monitoring program of the Dry Creek redband trout population. During 2012, 2013, and 2014, fin clips were taken from 352 redband trout collected throughout the Dry Creek watershed. Genetic analyses of fin clips were carried out at the Idaho Department of Fish and Game, Fish Genetics Laboratory in Eagle, Idaho. Each fish was genotyped at 186 SNPs, used by IDFG for genetic stock identification and determining range-wide relationships among rainbow trout/steelhead populations. Genetic data were used to monitor: 1) sex ratios; 2) genetic purity; 3) genetic differentiation between trout collected above and below the Bogus Basin Road culvert; 4) population-level genetic diversity; and 5) spatial distribution of related individuals. The continued monitoring of this population should assist efforts to design an effective watershed management plan.

Population genetics of Columbia River redband trout, Oncorhynchus mykiss gairdneri, in Dry Creek, Idaho