Lake trout
Lake trout, scientifically known as Salvelinus namaycush, are a unique species of fish native to the northern regions of North America, although they have been introduced in various parts of the world. Commonly referred to as "togue" in the eastern United States and "mackinaw" in the west, these fish exhibit a range of colors, primarily blue-gray or bronze-green, and are characterized by pale spots on their bodies. Lake trout can grow impressively large, reaching weights of over 100 pounds and lengths of up to 50 inches, though sizes between 15 and 40 pounds are more typical.
These fish inhabit cold, shallow waters in colder months and can dive to depths of up to 300 feet during warmer periods. They breed in rocky lake bottoms in the fall, where females lay eggs without constructing nests. The eggs typically take four to six months to hatch, depending on water temperature, with young lake trout initially feeding on insects and crustaceans. Adult lake trout primarily consume other fish and aquatic invertebrates. They are also sought after in commercial fisheries, particularly the siscowet variety, known for its oily flesh. Despite their commercial value, lake trout are not considered a threatened species and can live up to 20 years, with their main predators being birds like eagles and larger fish such as muskies and northern pike.
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Lake trout
While many different species of trout inhabit lakes, this species is the only one called "lake" trout. The lake trout is also called togue in the eastern United States, mackinaw in the western United States, and gray trout in Canada. The lake trout is actually a member of the char family.
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Salmoniformes
Family: Salmonidae
Genus: Salvelinus
Species: Namaycush
Lake trout are native to the northern areas of North America, although they have been introduced other places throughout the world. While lake trout come in a variety of colors, the most common color is blue-gray or bronze-green. Most lake trout have pale spots on their sides, backs and on the dorsal, adipose, and caudal fins. Each trout's anal fin, which is located just before the tail on the fish's bottom side, is made up of 11 rays. Each ray is a thin, finger-like spine connected to the ray beside it with a web-like material. The color of lake trout flesh varies from white to red. Lake trout can reach a weight of over 100 pounds (45 kilograms), but a weight of beween 15 and 40 pounds (seven and 18 kilograms) is more common. Lake trout can be up to 50 inches (130 centimeters) long. The tails of the lake trout are forked, or wedge-shaped.
Lake trout inhabit cold, shallow waters during the late fall, winter, and early spring. At other times, they move to deeper depths, sometimes as deep as 300 hundred feet (90 meters). In the northern regions, where the surface waters are cold even during the summer, lake trout are not forced into deeper depths.
Lake trout breed in the fall, although it is dependent on temperature. Breeding takes place along the rocky bottoms of lakes at depths of 100 feet (30 meters) or more, as well as in the shoal water, or shallow water, of some lakes. Females do not build redds, or nests, for their eggs as do other fish. They merely clean the area where the eggs are to be laid, using sweeping motions of their tails. Spawning takes place between September and December, the exact times varying between lakes.
As spawning begins, groups of females congregate, or join together, with several males at the spawning site. The females lay their eggs along the bottom of the lake. The eggs are tiny, measuring only 1/5 of one inch (1/2 centimeter) in diameter. A good number of the eggs are quickly eaten by small lake trout, bullheads, suckers, eels, yellow perch, and other fish.
The length of the incubation period for lake trout eggs depends on the water temperature and can take between four and six months. After hatching, young lake trout remain in shallow water where they feed on insects and crustaceans.
The diet of adult lake trout consists of fish, such as ciscoes, burbot, sculpins, and kokanee. Lake trout also eat worms, leeches, and aquatic invertebrates, or animals without a backbone.
Some lake trout have been targeted by large commercial fisheries. Siscowets, for example, are sought after by fishermen for their oily flesh which is popular on the commercial market. Siscowets are deep-running fish, caught at depths of 300 to 600 feet (90 to 180 meters). While this species swims deeper than the lake trout (Salvelinus namaycush), the two species are often caught in the same areas, both in shallow and deep water.
The main predators of the lake trout are eagles, muskies, and northern pike, although juvenile lake trout are more at risk for predation than adults. Lake trout live up to 20 years. They are not a threatened species.
Bibliography
“Lake Trout Fish Facts - Salvelinus Namaycush.” A-Z Animals, 21 Feb. 2023, a-z-animals.com/animals/lake-trout. Accessed 20 Apr. 2024.
Tomelleri, Joseph R. “Fish - Lake Trout.” State of Michigan, 2024, www.michigan.gov/dnr/education/michigan-species/fish-species/lake-trout. Accessed 20 Apr. 2024.