Whitefish, the common name for several fish found in temperate and cool regions of the Northern Hemisphere. The lake whitefish, one of the most valuable food fishes of the Great Lakes, is found northward to within the Arctic Circle. It has a spindle-shaped body, a small, toothless mouth, and a forkedW tail. It is olive above and white below. An adult usually weighs 2 to 5 pounds (0.9 to 2.3 kg) but sometimes exceeds 20 pounds (9 kg). It grows to be as much as 24 inches (60 cm) long.Whitefish are valuable food fishes of the Great Lakes.
Many whitefish, including the mountain whitefish and round whitefish as well as the lake whitefish, are fished for sport. The mountain whitefish, found in lakes and streams of the northern Pacific coastal states and in British Columbia, averages 12 inches (30 cm) in length. The round whitefish, similar in size to the mountain whitefish, is found in streams and lakes in the Great Lakes regions, in northern New England, and in many parts of Alaska and Canada.
Whitefish belong to the family Salmonidae. The lake whitefish is Coregonus clupeaformis; the mountain whitefish, Prosopium williamsoni; the round whitefish, P. cylindraceum.