Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for the Klamath River and Columbia River Distinct Population Segments of Bull Trout

The Fish and Wildlife Service (Service) determines threatened status for the Klamath River and the Columbia River distinct population segments of bull trout (Salvelinus confluentus), with special rules, pursuant to the Endangered Species Act of 1973, as amended (Act). The Klamath River population segment is limited to seven geographically isolated stream areas representing a fraction of the historical habitat. The distribution and numbers of bull trout have declined in the Klamath River basin due to habitat isolation, loss of migratory corridors, poor water quality, and the introduction of non-native species. The Columbia River population segment is represented by relatively widespread subpopulations that have declined in overall range and numbers of fish. A majority of Columbia River bull trout occur in isolated, fragmented habitats that support low numbers of fish and are inaccessible to migratory bull trout. The few remaining bull trout ``strongholds'' in the Columbia River basin tend to be found in large areas of contiguous habitats in the Snake River basin of central Idaho mountains, upper Clark Fork and Flathead Rivers in Montana, and several streams in the Blue Mountains in Washington and Oregon. The decline of bull trout is primarily due to habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, past fisheries management practices, and the introduction of non-native species. The special rules allow the take of bull trout in the Columbia River and Klamath River population segments if in accordance with applicable State and Native American Tribal fish and wildlife conservation laws and regulations and conservation plans approved by the Service. The listing proposal was restricted by court order to information contained in the 1994 administrative record. This final determination was based on the best available scientific and commercial information including current data and new information received during the comment period.