On the lower (warmwater) course of the river, low summer flows and poorer water quality from agricultural runoff limit fishery production. This section of river supports a fair fishery for largemouth bass , smallmouth bass, and channel catfish . Upstream from Star , the river is a coldwater stream and supports a greater variety of fish. The most prevalent species on this section is mountain whitefish , as well as hatchery-reared rainbow trout , wild rainbow trout, and fingerling brown trout . Upstream from Lucky Peak and Arrowrock reservoirs, the river and its tributaries contain excellent populations of wild rainbow trout, mountain whitefish, and bull trout. This is especially true immediately downstream from the outflow of Anderson Ranch reservoir, where the South Fork takes on the characteristics of a classic "tailwater" for over 5 miles (8 km) from the put-in below the dam to Cow Creek Bridge.