Fish
Lake Trout
Salvelinus namaycush · also called mackinaw, togue
Deep beneath the warm surface of a northern lake in midsummer, a lake trout holds steady in cold, dark water it may have occupied for the better part of a century, entirely unbothered by conditions near the surface that would be intolerable to a fish this committed to the cold.
Overview
The lake trout, Salvelinus namaycush, is a long-lived char native to cold, deep lakes across northern North America, including the Great Lakes and lakes throughout Canada and Alaska. Its remarkable potential lifespan and dramatic historical decline and recovery in the Great Lakes make it one of the more ecologically significant cold-water fish on the continent.
A trout in name only
Genetics place the lake trout firmly among the chars rather than the true trout its common name suggests, a classification technicality that does nothing to diminish its status as one of the largest, longest-lived, and coldest-water-loving fish found in any North American lake.
Status
Least Concern — widespread across suitable cold, deep lake habitat throughout northern North America, following recovery from severe historical sea lamprey impacts in the Great Lakes.
Lake Trout: common questions
Is the lake trout actually a trout?
Not technically — despite its common name, the lake trout is classified as a char, genus Salvelinus, making it more closely related to the brook trout and Arctic char than to true trout such as the brown or rainbow trout, which belong to different genera within the wider salmon family.
How long can a lake trout live?
Lake trout in some of the coldest, most northern lakes have been documented living for well over a century, a lifespan far beyond what most freshwater fish achieve and among the longest recorded for any fish living entirely in fresh water.
Why did lake trout decline so severely in the Great Lakes?
Lake trout populations in the Great Lakes were severely depleted during the twentieth century by the invasive sea lamprey, a parasitic fish that attaches to and kills larger fish, prompting large-scale lamprey control programmes and ongoing lake trout stocking efforts that continue today to help sustain the population.
Where does the lake trout live?
The lake trout is native to cold, deep lakes across northern North America, including the Great Lakes and numerous lakes throughout Canada and Alaska, generally retreating to the coldest available water as surface temperatures warm through the summer.