Fish Facts » Brook Trout
The brook trout's body is elongate and is only slightly laterally compressed; the body has its greatest depth at or in front of the origin of the dorsal fin (Scott and Crossman, 1985). Another physical characteristic of the brook trout is an adipose fin and a caudal fin that is slightly forked (Hubbs and Lagler, 1949). Brook trout have 10-14 principle dorsal rays, 9-13 principle anal rays, 8-10 pelvic rays, and 11-14 pectoral rays (Scott and Crossman, 1985). The brook trout also has a large terminal mouth with breeding males developing a hook or kype on the front of the lower jaw (Scott and Crossman, 1985). The coloration of the brook trout is very distinct and can be spectacular. The back of the brook trout is dark olive-green to dark brown, sometimes almost black, the sides are lighter and become silvery white ventrally (Scott and Crossman, 1985). On the back and top of the head there are wormy cream colored wavy lines known as vermiculations which break up into spots on the side (Scott and Crossman, 1985). In addition to the pale spots on the side there are smaller more discrete red spots with bluish halos (Scott and Crossman 1985). The fins of the brook trout are also distinct; the dorsal fin has heavy black wavy lines, the caudal fin has black lines, the anal, pelvic and pectoral fins have white edges followed by black and then reddish coloration (Scott and Crossman, 1985). (Hubbs and Lagler, 1949; Scott and Crossman, 1985)
Brook trout are found in three types of aquatic environments: rivers, lakes, and marine areas. Their living requirements in these environments are very specific. The freshwater populations occur in clear, cool, well-oxygenated streams and lakes (Scott and Crossman, 1985). Brook trout thrive in these environments with temperatures that remain below 18.8 C and where there is little to no siltation (LaConte, 1997). Stream dwelling brook trout require three habitat components, which include resting areas in pools, feeding sites near riffles or swiftly flowing water, and escape cover which normally is found along undercut banks, under woody debris, trees or large rock ledges ("Brook Trout," 1987). Brook trout that reside in marine environments migrate there from freshwater tributaries and tend to stay close to river mouths. ("Brook Trout", 1987; LaConte, 1997; Scott and Crossman, 1985)
The food habits of brook trout vary according to their age and life history stage. As fry, or very young fish, brook trout feed primarily on immature stages of aquatic insects (Everhart, 1961). In general a brook trout's diet can be likened to a smorgasbord of organisms with prey ranging from mayflies to salamanders (Wittman, 2001). A brook trout will virtually eat anything its mouth will accommodate, including mostly many aquatic insect larvae such as caddisflies, mayflies, midges, and black flies. Other organisms consumed include worms, leeches, crustaceans, terrestrial insects, spiders, mollusks, a number of other fish species (cannibalism is limited to spawning time and spring), frogs, salamanders, snakes and even small mammals like voles (e.g. Microtus, Cleithrionomys), should they find one in the water (Scott and Crossman, 1985). As brook trout become larger their diet shifts more towards a piscovourus one (Everhart, 1961). Sea-run brook trout eat fish and intertebrates that are commonly found in marine environments (Scott and Crossman, 1985).
The brook trout is a popular game fish 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.
The species has an average length of 38.1 - 50.8 cm
Brook trout are found as far south as Georgia in the Appalachian mountain range and extend north all the way to Hudson Bay. From the east coast their native range extends westward to eastern Manitoba and the Great Lakes (Willers, 1991). The fish has been introduced, very successfully in some areas, into many parts of the world including western North America, South America, New Zealand, Asia, and many parts of Europe (Scott and Crossman, 1973). (Scott and Crossman, 1985; Willlers, 1991)
University of Michigan Museum of Zoology Animal Diversity Web
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