Any of several prized game and food fishes of the family Salmonidae, native to the Northern Hemisphere but widely introduced elsewhere. Though most species inhabit cool fresh waters, a few (called sea trout; e.g., cutthroat trout) migrate to the sea between spawnings. Some weakfish are also called sea trout. The genus Oncorhynchus includes salmon and several trout species; Salvelinus contains trout species regarded as chars. Trout species vary greatly in anatomy, colour, and habits. Most live among submerged objects or in riffles and deep pools, eating insects, small fishes and their eggs, and crustaceans. See alsobrook trout; brown trout; lake trout; rainbow trout.