Habitat Type: Freshwater
Comments: Mostly in cold, medium to high gradient streams, but lake and sea-run populations also exist. Tends to occupy deeper, lower velocity, and warmer waters than other species of trout (Sublette et al. 1990). Does best where dissolved oxygen concentration is at least 9 ppm and, in small streams, where canopy shade is 50-75% at midday (Sublette et al. 1990). Some migratory populations spend first 2 years in river, 1-2 years in lake, then return to river to spawn at 3-4 years. Spawns in waters ranging from large streams to small spring- fed tributaries; in shallow gravelly headwaters, rocky lake margins, or sometimes over sand or hard clay if no gravel available. Spawns in natal stream. Fry occupy quiet waters along shorelines or in shelter of objects that deflect flows (Sublette et al. 1990).