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. Seealso brook trout; brown trout; lake trout; rainbow trout.
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Popular freshwater game fish (Salvelinus fontinalis), a variety of char, that is valued for its flavour and its fighting qualities when hooked. The brook trout is a native of the northeastern U.S. and Canada and has been transplanted to many parts of the world. It lives in cold, clean waters and carries dark, wormlike markings on the back and red and whitish spots on the body. The brook trout may weigh up to 6 lbs (3 kg). Some individuals migrate to large lakes or the sea and grow much larger and more silvery.
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Any of several species (genus Cynoscion) in the drum family (Sciaenidae), carnivorous bottom-dwelling fishes along warm and tropical seashores. The name weakfish refers to their delicate mouth, which is easily torn by fishhooks. About six species inhabit North American coasts. The weakfish, or sea trout (Cynoscion regalis), is a sport fish but is usually less than 2 ft (60 cm) long. Weakfish are caught commercially along the Middle Atlantic coastal states and are considered the most economically important species in the family. The spotted sea trout (C. nebulosus) is found along Florida's Atlantic and Gulf coasts. Sea trouts resemble but are not related to true trouts.
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Large, voracious char (Salvelinus namaycush) found widely from northern Canada and Alaska to New England and the Great Lakes, usually in deep, cool lakes. They are greenish gray and covered with pale spots. In spring, 5-lb (2.3-kg) lake trout are caught in shallow water; in summer, fish of up to 100 lbs (45 kg) are trolled in deep water. Lake trout were virtually eliminated from the Great Lakes by the sea lamprey, which entered through the Welland Canal in the 1930s. They have been introduced in the western U.S., South America, Europe, and New Zealand.
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Species (Oncorhynchus mykiss) of fish in the salmon family (Salmonidae) noted for spectacular leaps and hard fighting when hooked. It has been introduced from western North America to many other countries. A brightly coloured fish of lakes and swift streams, it is covered with small black spots and has a reddish band along either side. The steelhead, a large, bluish, oceangoing form, is also a prized game fish. Rainbow trout may weigh 6 lb (2.8 kg); steelheads (and rainbows in large lakes) may weigh 10–20 lb (4.5–9 kg) or more. Another form of rainbow, the Kamloops, or Kootenay, trout of Idaho, may exceed 30 lb (14 kg).
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Black-spotted game fish (Salmo clarki) of the salmon family, found in western North America. The cutthroat trout is named for the bright red streak beneath its lower jaw. Considered a good table fish, it strikes at flies, baits, and lures. It reaches a weight of 4 lb (1.8 kg). Many cutthroat trout that live in rivers migrate to sea. Like oceanic forms of other trout species, these fish are called sea trout and may not reenter freshwater for several years.
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Brown trout (Salmo trutta)
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Trout are usually found in cool (50-60°F, 10-15°C), clear streams and lakes, although many of the species have anadromous strains as well. Young trout are referred to as troutlet or troutling. They are distributed naturally throughout North America, northern Asia and Europe. Several species of trout were introduced to Australia and New Zealand by amateur fishing enthusiasts in the 19th century, effectively displacing and endangering several upland native fish species. The introduced species included brown trout from England and rainbow trout from California. The rainbow trout were a steelhead strain, generally accepted as coming from Sonoma Creek. The rainbow trout of New Zealand still show the steelhead tendency to run up rivers in winter to spawn. The speckled trout, found in the Gulf of Mexico and other places in the United States, is not in fact a trout at all, but a member of the drum family.
Trout have fins entirely without spines, and all of them have a small adipose (fatty) fin along the back, near the tail. There are many species, and even more populations that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be a large number of species is considered a much smaller number of distinct species by most ichthyologists. The trout found in the eastern United States are a good example of this. The brook trout, the aurora trout, and the (extinct) silver trout all have physical characteristics and colorations that distinguish them, yet genetic analysis shows that they are one species, Salvelinus fontinalis.
Lake trout (Salvelinus namaycush), like brook trout, actually belong to the char genus. Lake trout inhabit many of the larger lakes in North America, and live much longer than rainbow trout, which have an average maximum lifespan of 7 years. Lake trout can live many decades, and can grow to more than .