Interior Redband Trout
of the spokane river watershed

genetic studies on redband trout

Washington State Department of Fish and Wildlife Genetic Study

The Washington State Department of Fish and Wildlife (WDFW) recently completed a genetic study on redband and rainbow trout throughout various tributaries in the greater Spokane River Watershed.  This study was completed as part of a larger Joint Stock Assessment Program in coordination with funding from the Bonneville Power Administration, the Kalispel Tribe, and the Avista Corporation. The Spokane County Conservation District assisted in the tissue sample collections on some smaller tributaries (Marshall Creek, California Creel, Rock Creek) of Hangman Creek, a major tributary of the Spokane River. 

The purpose of the study was to examine the population structure and determine the occurrence of hatchery stock introgression.  The DNA within the tissue samples was analyzed for genetic composition to establish whether the fish were of native or hatchery-origin. 

The WDFW study revealed that populations of redband trout can be found in the upper Spokane River (between Post Falls and Upriver dams), the lower Spokane River (between Spokane Falls and Nine Mile Falls Dam), several smaller streams, and the mainstem of the Little Spokane River.  Many of these populations are genetically pure (no hybridization with non-native trout), while others show small amounts of hybridization with hatchery-origin coastal rainbow trout.  The map below depicts areas within and surrounding Spokane County of known locations of redband trout habitats. 

North Central High School DNA study

Randy James, an Advanced Biology and Science teacher, and a group of students from North Central High School conducted a study using identical tissue samples provided by WDFW from the California Creek collection.  Their study examined the genetic composition of the suspected redband, but with the purpose of determining genetic diversity among the redband as a possible positive adaptation. 

Students identified and measured trout found in California Creek.