- The bull trout is a char most closely related to white-spotted char of northeast Asia
- Historic range from northern California (McCloud River) and Nevada to northern Canada, now extirpated from California
- One of the most restricted temperature tolerances of any North American salmonid: optimal growth at ~13°C, decline in feeding ≥16°C
- Exhibit diverse life histories, including resident, potamodromous, and anadromous forms
- Known for piscivory at large sizes
- Once maligned as “trash fish” subject of eradication efforts during early 20th century
- Bull Trout once widely distributed in Upper Klamath Basin at least as far downstream as Keno.
- At least 40% of historical Bull Trout populations in the basin have experienced recent extirpation (Buchanan et al. 1997).
- Bull Trout now limited to discrete isolated headwater populations.
- Listed as threatened under ESA in Klamath in 1998, prior to range-wide listing in 1999
- Basin-wide recovery goals include expanding populations downstream.
- In 1989 Bull Trout in Sun Creek were restricted in distribution to 1.9 km and numbered approximately 150 individuals.
- Threats included nonnative Brook Trout (S. fontinalis) and lack of habitat connectivity due to irrigation of private land.