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Brook Trout (Salvelinus fontinalis) - Wiki
| 제목: | Brook Trout (Salvelinus fontinalis) - Wiki
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Brook trout
From Wikipedia, the free encyclopedia
[Photo] A photograph of Brook Trout (Salvelinus fontinalis). Photo taken at the Pittsburgh Zoo. Date Sunday, February 18, 2007. Author Photo by and (C)2007 Derek Ramsey (Ram-Man) http://en.wikipedia.org/wiki/User:Ram-Man
The brook trout (Salvelinus fontinalis) is a species of fish in the salmon family (family Salmonidae) of order Salmoniformes. In many parts of its range, it is known by the name speckled trout.
Habits and range
The brook trout is native to small streams, creeks, lakes, and spring ponds. Some brook trout are anadromous. Though commonly considered a trout, the brook trout is actually a char, along with lake trout, bull trout, Dolly Varden and the Arctic char. It is native to a wide area of eastern North America but increasingly confined to higher elevations southward in the Appalachian Mountains to northern Georgia, Canada from the Hudson Bay basin east, the Great Lakes???Saint Lawrence system, and the upper Mississippi River drainage as far west as eastern Iowa.
Description
The brook trout is of dark green to brown basic colouration with a distinctive marbled pattern (called vermiculations) of lighter shades across the flanks and back and extending at least to the dorsal fin, and often to the tail. There is a distinctive sprinkling of red dots, surrounded by blue haloes, along the flank. The belly and lower fins are reddish in colour, the latter with white leading edges. Often the belly, particularly of the males, becomes very red or orange when the fish are spawning. The species reaches a maximum recorded length of 86 cm (33 in) and a maximum recorded weight of 9.4 kg (21 lb). It can reach at least seven years of age, with reports of 15-year-old specimens observed in California habitats to which the species has been introduced.
Environmental requirements
S. fontinalis prefers cool, clear waters of high purity and a narrow pH range in lakes, rivers, and streams, being sensitive to poor oxygenation, pollution, and changes in pH caused by environmental effects such as acid rain. Its diverse diet includes crustaceans, frogs and other amphibians, insects, molluscs, smaller fish, and even small aquatic mammals such as voles. It provides food for seabirds and suffers attack by lampreys. The brook trout is a short-lived species, rarely surviving beyond four or five years in the wild.
Individuals normally spend their entire life in fresh water, but some ??? colloquially called "salters" or "sea run" ??? may spend up to three months at sea in the spring, not straying more than a few kilometres from the river mouth. The fish return upstream to spawn in the late summer or autumn. The female constructs a depression in a location in the stream bed, sometimes referred to as a "redd", where groundwater percolates upward through the gravel. One or more males approaches the female, fertilising the eggs as the female expresses them. The eggs are slightly more dense than water. The female then buries the eggs in a small gravel mound. The eggs hatch in approximately 100 days.
A potamodromous population of brook trout native to Lake Superior, which run into inflowing rivers to spawn, are called "coasters". Coasters tend to be larger than most other populations of brook trout, often reaching 2 to 3 kg in size. Many coaster populations have been severely damaged by overfishing and by habitat alterations, especially by the construction of hydro-electric power dams, on their inflowing streams. In Ontario and Michigan, efforts are under way to restore and recover coaster populations.
Angling and commercial use
The brook trout is very popular with anglers, particularly fly fishermen. Today, many anglers practice catch-and-release tactics to preserve remaining brook trout populations, and organizations such as Trout Unlimited have been in the forefront of efforts to institute air and water quality standards sufficient to protect the brook trout. Revenues derived from the sale of fishing licenses have been used to restore many sections of creeks and streams to brook trout habitat. Brook trout are also commercially raised in large numbers for food production, being sold for human consumption in both fresh and smoked forms. Because of its dependence on pure water and a variety of aquatic and insect life forms, the brook trout is also used for scientific experimentation in assessing the effects of pollution.
Partially as a result of its popularity as a game fish, the brook trout has been introduced in some areas to which it was not originally native, and has become established widely throughout the world. In some parts of the world, the brook trout has had a harmful effect on native species, and is a potential pest.
Brook trout can sometimes hybridise with other species. One such hybrid, between the brook trout and the brown trout (genus Salmo) is the tiger trout. Tiger trout occur very rarely naturally but are sometimes artificially propagated. Such crosses are almost always reproductively sterile.
Human-caused habitat destruction
Brook-trout populations depend on cold, clear, well-oxygenated water of high purity. As early as the late 19th century, native brook trout in North America became extirpated from many watercourses as land development, forest clear-cutting, and industrialization took hold. Streams and creeks that were polluted, dammed, or silted up often became too warm to hold native brook trout, and were colonized by transplanted smallmouth bass and perch or other introduced salmonids such as brown and rainbow trout. The brown trout, a species not native to North America, has replaced the brook trout in much of the brook trout's native water. Brook trout populations, if already stressed by overharvest or by temperature, are very susceptible to damage by the introduction of exogenous species. In many lakes to which brook trout were once native, they have been extirpated by the introduction of other species, particularly percids but sometimes other spiny-rayed fishes.
In addition to chemical pollution and algae growth caused by runoff containing chemicals and fertilizers, air pollution has also been a significant factor in the disappearance of brook trout from their native habitats. In the United States, acid rain caused by air pollution has resulted in pH levels too low to sustain brook trout in all but the highest headwaters of some Appalachian streams and creeks. Brook trout populations across large parts of eastern Canada have been similarly challenged; a subspecies known as the aurora trout was extirpated from the wild by the effects of acid rain.
Today, in many parts of the range, efforts are underway to restore brook trout to those waters that once held native populations, stocking other trout species only in habitats that can no longer be recovered sufficiently to sustain brook trout populations.
Trivia
The specific epithet fontinalis derives from the Latin font??n??lis (of or from a spring or fountain).
The Brook Trout is the state fish of Michigan, Virginia, New Jersey, New York, Pennsylvania, and West Virginia.
http://en.wikipedia.org/wiki/Brook_trout
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