Bull trout are a native char of the Pacific Northwest and Canada.  A fresh water fish, bull trout require clean, cool water to survive and reproduce. 

Bull trout historically moved back and forth between major rivers and their tributaries, seeking suitable spawning and rearing grounds, and to avoid temperature extremes.  With the construction of major hydropower dams and innumerable irrigation diversions across the bull trout range, however, bull trout habitat has become badly fragmented; and populations have declined as bull trout can no longer migrate like they used to.

Livestock grazing, logging, roads, and other human actions have also seriously damaged streams and riparian areas in bull trout habitat -- causing sedimentation and excessive water temperatures that kill bull trout and prevent successful reproduction.

After years of litigation, the US Fish and Wildlife Service listed bull trout as a "threatened" species under the Endangered Species Act in 1998, based on these and other threats.  See 63 Fed. Reg. 31647 (6/10/98). 

The Salmon, Clearwater, Boise, and Payette River basins in Idaho offer some of the best remaining bull trout populations, along with parts of Montana and Oregon.  Yet these areas continue to suffer from excessive irrigation diversions, dams, irresponsible grazing and logging, and other threats.  With global climate change, stream temperatures are expected to climb across the bull trout range, further imperilling the species.

Preserving bull trout will require public land managers to eliminate the "stressors" that degrade bull trout habitat -- such as grazing and logging -- and to reconnect rivers and streams by eliminating old dams and reducing inefficient irrigation diversions.