Fish and Aquatic Conservation



illustration of a Lake trout

Lake trout

Salvelinus namaycush, (Walbaum, 1792)

Cool Facts

Lake trout are the largest of the freshwater char. Splakes (hybrid fish, crossed between lake trout and brook trout) have also been successfully introduced widely in many areas of North America. Lake trout are highly susceptible to pollution. A maximum recorded weight of 102 lbs. ( 46.4 kg) was recorded in the state of Alaska. Lake trout have been reported to live up to 40 years in some Canadian lakes.

SIZE: Common length for lake trout is 50 cm (19.7 inches) with the largest recorded length being 150 cm (59 inches).

RANGE: Within North America, lake trout are widely distributed from northern Canada and Alaska, south to New England and the Great Lakes basin. Lake trout have been introduced to many areas outside of their native range within the United States.

HABITAT: Most lake trout, as their name infers, inhabit deep lakes although they can exist in freshwater streams. Lake trout can rarely occur in brackish water.

DIET: Lake trout generally feed on a variety of organisms such as freshwater sponges, crustaceans, insects, fishes (with a preference for ciscoes or “lake herring”), and small animals. Some populations feed on plankton throughout their lives. Plankton feeding lake trout grow more slowly, mature earlier and at a smaller size, die sooner and attain smaller maximum size than their piscivorous cohorts.

Natural History

Lake trout do not construct nests but are broadcast spawners. Lake trout normally spawn during the fall months. Female lake trout are “courted” by male lake trout by butting her in the side and swimming beside her. Spawning occurs at night and may include several individuals in a spawning group. Fertilized trout eggs then sink down to the lake bottom where they become lodged between gravels and boulders.

Conservation

The status of lake trout populations varies within North America. The U.S. Fish and Wildlife Service has been working with both the states and the Great Lakes Fishery Commission to establish self‐sustaining populations of lake trout in Lake Superior. Lake trout populations in Lake Michigan and Lake Huron are showing signs of improvement, but additional research must be done to improve lake trout sustainability in both of these lakes.