Bull trout are members of the char subgroup of the salmon family. They require very cold, clean water to thrive and are excellent indicators of water quality and stream health. Montana bull trout display various life history strategies. Some bull trout are residents, spending the stream in which they were born. Other bull trout have migratory life histories, either living in major rivers as sub-adults and adults and then migrating into smaller tributaries to spawn (fluvial) or living in lakes and
reservoirs as sub-adult and adults and migrating into tributaries to spawn (adfluvial). Migratory bull trout can move distances greater than 150 miles in response to environmental changes and spawning cues.

Bull trout can live more than 20 years. In Montana, bull trout are native to rivers, streams and lakes in the Columbia (Kootenai, Clark Fork, Bitterroot, Blackfoot, Flathead, and Swan drainages) and Saskatchewan River (St. Mary and Belly drainages) basins. Bull trout have declined due to habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, past fisheries management, and the introduction of non-native species such as brown, lake and brook trout. The spawning areas susceptible to development, as silt can easily smother bull trout redds.

While bull trout occur over a large area, their distribution and abundance has declined and several local extinctions have been documented. Many of the remaining populations are small and isolated from each other, making them more susceptible to local extinctions.

Information Courtesy of Montana Fish, Wildlife, and Parks