Lake trout (Salvelinus namaycush) is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char (or charr), touladi, togue, and grey trout. In Lake Superior, it can also be variously known as siscowet, paperbelly and lean. The lake trout is prized both as a game fish and as a food fish.
From a zoogeographical perspective, lake trout are quite rare. They are native only to the northern parts of North America, principally Canada, but also Alaska and, to some extent, the northeastern United States. Lake trout have been widely introduced into non-native waters in North America and into many other parts of the world, mainly Europe, but also into South America and certain parts of Asia. Although Lake Trout were introduced into Yellowstone National Park's Shoshone, Lewis and Heart lakes legally in the 1890s, they were illegally or accidentally introduced into Yellowstone lake in the 1980s where they are now consideredinvasive.