The westslope cutthroat trout (Onchorynchus clarki lewisi) is native to the drainages of Sanders County. The threatened native bull trout relies on westslopes as a major prey species in its piscivorous diet. Catch and release fishing is required to maintain fishable populations of the two natives, which now compete with introduced rainbow trout, and warm-water species, such as largemouth bass, yellow perch, Northern Pike, and walleyes that have been introduced and thrive in the modified habitat of the Clark Fork River's reservoirs.
the westslope cutthroat trout (onchorynchus clarki lewisi) is native to the drainages of sanders county the threatened native bull trout relies on westslopes as a major prey species in its piscivorous diet catch and release fishing is required to maintain fishable populations of the two natives which now compete with introduced rainbow trout and warm-water species such as largemouth bass yellow perch northern pike and walleyes that have been introduced and thrive in the modified habitat of the clark fork river's reservoirs