The brook trout is the state's only native mountain trout. The rainbow and brown trout are introduced species. The brook trout prefers fast-flowing mountains streams with an average water temperature of about fifty degrees. At one time brook trout were abundant in larger mountain streams, but the intrusion of farming and logging has driven the trout out. Now the only suitable natural habitat for brook trout is in the smallest streams found at higher elevations. Cornell discusses the brook trout's life history and its importance as a game fish.