Brook trout (Salvelinus)
The brook trout's body is mostly dark green to charcoal colored, with pale yellow markings on the back and sides. These speckled markings fade down the sides and give way to yellow spots encircled in a blue ring. Unlike other trout, brookies are actually members of the char family, a close relative to trout and salmon, which explains the white edges on their bottom fins. This leads into a black stripe and pale yellow or slightly red coloring toward the back of the fins. The tail is nearly square with a barely visible fork.
Brook trout are opportunistic feeders and feed mostly in early morning and evening. They will eat a wide variety of food from small bugs to small amphibians. The bulk of a stream or river brook trout's diet is made up of aquatic insects. Coasters, the lake version of brook trout, will consume prey fish as well, and can eat as much as half its body weight in minnows per week.
Brook trout are the only stream-dwelling fish native to the Great Lakes region. They are currently present in every state except Alabama, Arkansas, Florida, Hawaii, Kansas, Louisiana, Missouri, Mississippi, Oklahoma, and Texas. Brook trout have been introduced in waters throughout the Rocky Mountain states, as well as Delaware, Illinois, Kentucky, and North and South Dakota. They are native to all other states.
Brook trout will inhabit calm water in small mountain lakes as well as small and medium-sized rivers and streams with swift current. Brookies need clean, cool water with a maximum temperature of 68 F or less. Their preferred temperature range is 57 to 61 F, and they may move from streams into lakes or the sea to avoid high temperatures in summer. Brook trout are not heavy schoolers, but they do prefer to travel in pairs or small groups.
Brook trout often like to hide under overhanging banks, around rocks and boulders, and under logs for protection from shore birds such as great blue herons, cormorants and kingfishers. They will also congregate over moss and vegetation on a stream bottom to mask their presence from birds and other predators.
- Brook trout are the state fish for Michigan, New Jersey, West Virginia, and Pennsylvania.
- Brook trout are very aggressive and have threatened a number of other fish populations such as native cutthroat and rainbow trout in Idaho and Colorado, and river cutthroat in the lower elevation Rocky Mountain streams. However, in Great Smoky Mountain National Park, brook trout are being displaced by non-native rainbow trout.
- Hybrids of the brook trout are the tiger trout, splake, and sparr. These have come about because the lake trout, brown trout, and arctic charr spawn at relatively the same time in the fall.
- The aurora trout are a subspecies of the brook trout.