Lake Trout, Salvelinus namaycush
Identifying characteristics: (Native Fish) The Lake Trout has light spots on a black to gray background, which progressively get lighter moving down the side of the fish. The belly is white. The lower fins are often orange to orange-red with a leading white edge. The darker colored back has a dorsal fin and an adipose fin. The tail or caudal fin is deeply forked with equal sized upper and lower lobes. The anal fin has 8-10 rays with a leading white edge.
The Lake Trout, sometimes called "salmon trout", is the largest native trout species of Michigan. Historically and still today it can be found in all five of the Great Lakes and many large, deep, cold water inland lakes of Michigan. The Lake Trout prefers water temperatures between 40-55 degrees Fahrenheit. In the fall, winter and spring seasons this fish may be found in shallow water areas of the lake, 10 to 30 feet deep. As near shore waters warm in the summer, it follows the cold water temperatures to depths of 100 to 200 feet or more. In the Great Lakes environment Lake Trout will often range many miles in search of prey. The Lake Trout, as adults, feed primarily on other fish. The native prey includes ciscoes and sculpin, but when available Lake Trout will take advantage of alewives, smelt, gobies or other fish and sometimes take crustaceans, terrestrial insects, plankton, even small birds and mammals.
There are several subspecies of Lake Trout in Lake Superior that can be identified by their external characteristics and environment preference. The three more commonly referenced subspecies are the inshore lean (mackinaw), humper and the siscowet or "fat trout". The inshore lean (mackinaw) is often found is waters of less than 200 feet. The humper strain Lake Trout inhabits off shore islands and reefs. The siscowet occurs often in the deep waters of Lake Superior, 200 feet or greater in depth. This "fat trout" will also spawn at depths greater than 300 feet.
Lake Trout are fall season broadcast spawning fish on shoals or shallow reefs. They do show homing behavior and will return each year to the same spawning area. The eggs are deposited after dark, among the cobble and gravel of the lake bottom. Young Lake Trout will hatch from the egg and stay among the cobble substrate as sac fry. As swim-up fry stage occurs in early spring, they will emerge from the protective rocky substrate to feed on their own. Lake Trout become sexually mature at 6 or 7 years of age. The average adult weighs in at 9 to 10 pounds but some individuals weigh up to 50 pounds (the Michigan record is 61 pounds, 8 ounces). The life-span of the Lake Trout may exceed 25 years.
Over commercial fishing and the introduction of the parasitic sea lamprey severely reduced the Lake Trout populations in the Great Lakes from 1935 to 1965. Later, chemical contaminants may have also contributed to reproduction problems. Now with better fisheries management, control of the sea lamprey, and solving pollution problems, the invaluable Lake Trout stocks are coming back.
Lake Trout can successfully hybridize with brook trout to form "splake". This can occur naturally or more commonly in cultured hatchery conditions by fertilizing Lake Trout eggs with brook trout sperm. Splake will live for 5 or 10 years and can reach 16 pounds in weight. Splake in appearance are intermediate between the parent species.
Lake Trout are avidly sought after by commercial fishing operations and sport anglers for food as well as for the sport.
For more information on how and where to catch Lake Trout see our Michigan Fish and How to Catch Them and Better Fishing Waters.
Lake Trout graphic courtesy of Joseph R. Tomelleri and copyrighted.