Brook trout
image = Salvelinus fontinalis.jpg | image_width = 250px | regnum = Animalia | phylum = Chordata | classis = Actinopterygii | ordo = Salmoniformes | familia = Salmonidae | genus = Salvelinus | species = S. fontinalis | binomial = Salvelinus fontinalis | binomial_authority = (Mitchill, 1814)
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's known by the name speckled trout. The brook trout is native to streams, 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, including most of Canada from the Hudson Bay basin east, the Great Lakes–Saint Lawrence system, and the Mississippi River drainage in the United States as far south as northern Georgia.
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.
S. fontinalis prefers cool, clear waters in lakes, rivers, and streams, being sensitive to poor oxygenation. 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 species normally spends its entire life in fresh water, but some individuals—colloquially called "salters" or "sea run"—spend up to three months at sea in the spring, remaining within a few kilometres of river mouths. The fish return upstream to spawn in the late summer or autumn. The female constructs a depression in a location in the stream bed 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.
The brook trout is very popular with anglers. It is also raised in large numbers for commercial food production, being sold for human consumption both fresh and smoked. It is also used for scientific experimentation.
Because of its popularity as a game fish, the brook trout has been introduced and has become established widely throughout the world. It has often had a harmful effect on native species, and is a potential pest. Nonetheless, 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.
The specific epithet fontinalis derives from the Latin fontīnālis (of or from a spring or fountain).*
* *Aurora trout - A subspecies of Brook trout
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