Over the last two centuries, bull trout populations have declined across North America. The bull trout, Salvelinus confluentus, once thrived in the Columbia River Basin and coastal rivers of Washington and Oregon, extending north into British Columbia and Alberta.

Bull trout are members of the genus Salvelinus, which also includes Arctic char, brook trout, and lake trout. Like its relatives, male bull trout exhibit brilliant colors during the spawning season. Bull trout migrate during summer, traveling up to 150 miles from lakes and rivers upstream to their natal headwaters to spawn.

A variety of factors have been cited in the decline of bull trout. Habitat degradation and fragmentation, migratory fish passage obstacles, poor water quality, the effects of climate change, bounty fishing, and the introduction of non-native fish species.

Currently, American bull trout populations are scattered across portions of Oregon, Washington, Idaho, Montana, and Nevada. They populate several river systems including the Klamath,Columbia and Snake River Basins. In 1998, bull trout were listed as a threatened species under the Endangered Species Act.

In 2011, bull trout were re-introduced into the Clackamas River after a nearly 50-year absence. The reintroduction team included representatives from the U.S. Fish and Wildlife Service, Oregon Department of Fish and Wildlife, U.S.Geological Survey, and Mt. Hood National Forest. The project was one of several bull trout restoration programs that are ongoing in western river systems.