The brown trout is a member of the salmon family of fishes. They have: an elongate, laterally compressed body and a long head; a rounded snout and a pronounced hook which develops on the lower jaw in mature males; in stream populations, the back, upper sides and the top of the head are brown becoming silvery on the sides with pronounced black spots and rusty-red spots on the sides; in large lakes or the sea, the overall body colour appearance is silvery and most of the spots are concealed; and the fins, except for the adipose fin which is an orange colour, are smokey, opaque and sometimes yellowish with some spots on the dorsal, adipose and caudal fins.
The brown trout is native to Europe and western Asia. It was first introduced into Canadian waters in Quebec in 1890. Since then, successful introductions of the brown trout have been made in all provinces, except Prince Edward Island, Manitoba and the Northwest Territories. Presently, brown trout are found in the Ontario waters of the Great Lakes (Ontario, Erie, Huron and Superior) as well as many inland waters particularly in southcentral and southwestern Ontario.
The brown trout is a cold-water species that was introduced mainly into stream or river habitats in Canada, although there are now a number of lake or sea-run populations. The habitat of brown trout is clear, cool, well-oxygenated streams and lakes.
The brown trout has become increasingly popular as a game fish since it was introduced into Canadian waters. The brown trout can withstand less favourable environmental conditions, lives longer and grows bigger than the native brook trout.