Montana Field Guide

The Lake Trout is a char of the same genus as Bull Trout and Brook Trout. Lake Trout are native in the St. Mary and Missouri River drainages and have been introduced to a few other scattered mountain lakes, Flathead Lake, and Fort Peck Reservoir. Lake Trout are a major game fish in much of Canada and were at one time a staple of the Great Lakes fishery. In Montana, the Lake Trout of Flathead Lake have achieved trophy status, growing to 42 pounds. Lake Trout inhabit very deep, cold lakes, living in water up to 200 feet deep. They spawn in the fall on the rocky substrate of the shoreline. They scatter or broadcast their spawn, a rarity in the trout group. Small Lake Trout feed on plankton and aquatic invertebrates but fish over 2 to 3 pounds eat a fish diet. Lake Trout are a highly-prized food fish in Canada and are catching on as a game fish in Montana with the advent of downriggers, electronic fish finders, and other specialized techniques.

For a comprehensive review of the ecology, conservation status, threats, and management of this and other Montana fish species of concern, please see Montana Chapter of the American Fisheries Society Species of Concern Status Reviews.

Lake trout are typically trout-like in shape. Like other chars, lake trout have light spotting on a dark background that can range from light green to almost black. A narrow, sometimes indistinct, white anterior border is present on the pectoral, pelvic and anal fins. Lake trout can be distinguished from other chars by their deeply forked tail

Deep, cold lakes and reservoirs (Montana Department of Fish, Wildlife, and Parks 2003). Deep cold water lakes and reservoir with some rocky bottom and on abundance of forage fish. Spawns over rocky shoal areas in lakes in depths from 10 to 120 feet.

Young lake trout feed on plankton and aquatic invertebrates. Diet is largely other fish after reaching 2-3 lbs. in weight.

Whereas lake trout can be found in cold rivers and shallow lakes in the northern portion of its range (Scott and Crossman 1973), in Montana native lake trout inhabit a few relatively deep, cold lakes remaining from the Pleistocene glaciations.

Broadcasts spawn Oct-Nov. Eggs hatch in following March or April when water temperatures reach 34-38 degrees F. Fry soon move into deep water. No parental care.

The genetic uniqueness and significance of Montana's native lake trout populations to the post-glacial distribution of the species mandate that these remnant native populations be conserved.

Lake trout populations have been decimated by over-harvest, habitat loss, pollution, and introductions of non-native fish species, especially sea lampreys (Petromyzon marinus) into the Great Lakes. Efforts to re-establish native lake trout populations have generally not met management goals.