Brook Trout

Description:

This species is green to brown in basic colour, 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. A distinctive sprinkling of red dots, surrounded by blue haloes, occur along the flanks. The belly and lower fins are reddish in color, 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 6.6 kg (14.5 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. Typical lengths vary from 25 to 65 cm (10 to 26 in), and weights vary from 0.3 to 3.0 kg (0.7 to 7.0 lb). Growth rates are dependent on season, age, water and ambient air temperatures, and flow rates. In general flow rates affect the rate of change in the relationship between temperature and growth rate. For example in spring growth increased with temperature at a faster rate with high flow rates than with low flow rates.[6]

Habitat:

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. Many lacustrine populations of brook trout 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.[13] 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.[14] Today, in many parts of the range, efforts are underway to restore brook trout to

Notes:

Part of my Trout in the Classroom project