Cooperative Fish and Wildlife Research Units Program: Utah
Education, Research and Technical Assistance for Managing Our Natural Resources

Most subspecies of cutthroat trout Oncorhynchus clarkii are imperiled or extinct due to the combined effects of habitat degradation and interactions with exotic species. To quantify abundance and vital rates and evaluate trends, we selected a large population of Bonneville cutthroat trout O. clarkii utah from the Logan River of northern Utah, a river characterized by high-quality and connected habitat. Over a 15-year period, we have been continuing a comprehensive population assessment, including depletion-based abundance estimates and a mark–recapture study (2,000 tagged fish) of site fidelity, growth, and survival. Our results provide important conservation and recovery benchmarks for identifying rangewide limiting factors of cutthroat trout.