The Brook Trout is a species of fish in the salmon family of order Salmoniformes. 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 and contaminated waters.
Fisheries biologist Robert Behnke describes three forms of the Brook Trout. A large lake form evolved in the larger lakes in the northern reaches of it range and is generally piscivorous as adults. A sea-run form that migrates into salt-water for short periods of time to feed evolved along the Atlantic coastline. Finally, Behnke describes a smaller generalist form that evolved in the small lakes, ponds, rivers and streams throughout most of the original native range. This generalist form rarely attains sizes larger than 12 inches (30 cm) or lives for more than 3 years. All three forms have the same general appearance. The Brook Trout has a dark green to brown color, with a distinctive marbled pattern 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.
A simple fly fishing outfit or some basic, lightweight gear is adequate, as Brook Trout are not large fish. Brook Trout are aggressive feeders and eat a wide variety of food including worms, mayflies, grasshoppers, crickets and trout eggs. The larger Brook Trout will also chase and eat frogs, toads and other amphibians as well as smaller fish such as shiners. When angling for Brook Trout from the water, move slowly, without splashing. Allow the current to carry your bait downstream naturally for the best results. Fish the bottom of the water by attaching a sinker instead of the bobber, and allow the bait to fall. It should produce excellent results.
Brook trout are native to a wide area of eastern North America, but increasingly confined to higher elevations southward in the Appalachian Mountains to northern Georgia and northwest South Carolina, Canada from the Hudson Bay basin east, the Great Lakes–Saint Lawrence system, the Canadian maritime provinces and the upper Mississippi River drainage as far west as eastern Iowa. Their southern historic native range has been drastically reduced, with fish being restricted to higher elevation, remote steams due to habitat loss and introductions of brown and rainbow trout. As early as 1850, the Brook Trout's range started to extend west from its native range through introductions. Acclimatization movements in Europe, South America and Oceania resulted in Brook Trout introductions throughout Europe, in Argentina and New Zealand. Although not all introductions were successful, a great many established wild, self-sustaining populations of Brook Trout in non-native waters.
Brook Trout can be found in Canterbury's Lake Emily, a small mountain lake in the Ashburton group. There are also small populations of Brook Trout in Lake Dispute and Dingle Lagoon in the Upper Waitaki, and Lake Henry near Te Anau Blue Lake also contains a leftover stock of Brook Trout.