Lake Trout

The lake trout (Salvelinus namaycush) is a large freshwater fish native to North America. Contrary to popular belief, it is not actually a true trout. In reality, they belong to the char family. These prized game fish can grow to enormous sizes. They also grow quite slowly, which can make them susceptible to overfishing. 

5 Lake Trout Facts

• Despite its name, this fish belongs to the char genus Salvelinus. 
• They go by several names, including mackinaw, lake char, namaycush, togue, and gray trout. 
• Mature lake trout can eat prey over half their size. 
• They can live for over 25 years. 
• The largest lake trout ever recorded weighed 73.29 pounds and was caught in Colorado in 2023. 

Classification and Scientific Name

The lake trout belongs to the ray-finned class of fish, Actinopterygii. Its family, Salmonidae, includes several well-known freshwater fish, including salmon, char, trout, graylings, and lenoks. All members of the Salmonidae family collectively go by the name salmonids, or “salmon-like fish.” The fish’s genus name, Salvelinus, is a Latinized version of the German word saibling, meaning “a char.”

Meanwhile, its specific name namaycush derives from the word namekush. Several Southern East Cree tribes in Canada and around Hudson Bay used this word when referring to them. However, some other East Cree used different names, including kukamaw and kukamesh. The Ojibwe-speaking people of the Great Lakes also had their own names for them. Some of the most common Ojibwe names included namegos (lake trout) and namegoshens (little lake trout).

Most of their other common names stem from English or French versions of Native American words. For example, the name Mackinaw stems from the Algonquin word mitchimakinak, meaning “many turtles.” This word was later adopted for the Michigan port city of “Mackinaw” and, subsequently, the lake trout. Similarly, the French-Canadian word touladi stems from an Eastern Algonquian word for lake trout. On the other hand, some nicknames for them are based solely on their appearance. For instance, some anglers call dark-colored lake trout “mud hens” due to their large size and dark appearance. 

Appearance 

The lake trout ranks as the largest species of freshwater char. On average, adults measure between 24 and 36 inches long. Anglers commonly catch them weighing anywhere from 15 to 40 pounds. However, given enough time (and food), they can grow to a truly humongous size. The largest lake trout ever recorded weighed 73.29 pounds and was caught in Colorado in 2023.

Lake trout possess a noticeably forked tail. Their scales typically range from slate gray to light green on the sides and appear lighter on the belly. However, some specimens can appear dark green, brown, or gray. They feature yellow or cream-colored spots all across the head, body, and fins. In terms of overall appearance, they resemble other salmon, trout, or char.

Distribution, Population, and Habitat

Lake trout are native to North America. Traditionally, they lived in a narrow range throughout Canada, Alaska, and the northeastern United States. In the 19th and 20th centuries, fisheries introduced these fish into new habitats. Today, you can find them in parts of Europe, New Zealand, and South America. Lake trout were also legally introduced into the Shoshone, Heart, and Lewis Lakes in Yellowstone National Park. However, in the 1980s, they were illegally introduced into Yellowstone Lake, where they are now considered an invasive species.

Lake trout prefer cold, oxygen-rich freshwater lakes. They tend to inhabit relatively deep water, particularly during the summer. You can often find them at depths ranging from 60 to 200 feet below the surface.

Predators and Prey

Lake trout normally fill a spot near the top of the food chain in whatever habitat they occupy.

What Does Lake Trout Eat?

As juveniles, they primarily feed on aquatic insects such as mayflies, caddis flies, and midges. They also prey on plankton, terrestrial insects, worms, leeches, and aquatic invertebrates. Mature lake trout will eat just about anything that they can catch. They possess voracious appetites and eat a wide variety of prey, including crustaceans and small fish. Typical prey fish include smelt, minnows, and sculpin. In Yellowstone Lake, they frequently prey on native cutthroat trout. This predatory habit of feeding on cutthroat trout is one of the main reasons people consider them an invasive species in that environment.

What Eats Lake Trout?

Since they often inhabit pelagic waters, few mammals, reptiles, and amphibians prey on them. As a result, the only animals that frequently prey on them are other large, predatory fish and birds of prey. Juvenile and mature lake trout share many of the same predators. Aside from humans, some common predators of theirs include eagles, muskies, and northern pike.

Reproduction and Lifespan

Most spawn at night during the fall. However, spawning conditions and timing may change depending on the weather and environment. They spawn via broadcast spawning, wherein females spread millions of eggs over several spawning shoals. Males then come by and externally fertilize the eggs with their sperm. The eggs take anywhere from 4 to 6 months to hatch. Young lake trout, known as fry, tend to hide near the lake bed until they grow large enough to move into open water to hunt.

In the wild, these fish mature at different rates depending on their environment. Experts separate lake trout into two broad categories: planktivorous trout and piscivorous trout. Planktivorous variants live in lakes that lack pelagic forage fish. These trout mature slowly and tend not to grow especially large. Meanwhile, piscivorous variants live in lakes that contain deep-water food sources. Piscivorous lake trout typically mature much more quickly and can grow to an enormous size. They also tend to be far less abundant than planktivorous lake trout. On the far end of the spectrum, long-lived lake trout can reach over 20 years old.

Lake Trout in Food and Cooking

You can cook lake trout in various ways, including baked, grilled, fried, or boiled. That said, the most popular ways to cook this fish include grilling and baking. They have a strong, fishy taste that is more pronounced than salmon or whitefish. Due to this strong flavor, some people shy away from cooking it. However, you can reduce its flavor by first bleeding and soaking the fish. It possesses juicy, firm meat, so if you like eating other freshwater fish, you’ll probably enjoy it.

Lake Trout Population

Populations of this fish vary by region. In Lake Superior, their numbers declined during the late 19th century and early 20th century due to overharvest. However, thanks to strong regulations, their numbers rebounded in the 1970s. Recent reports indicate that lake trout populations in Lake Superior have been restored to sustainable, historic levels, but no specific population estimate is provided. Today, commercial fisheries continue to harvest them in the Great Lakes. However, fishing is more tightly controlled today than in earlier decades. Still, native populations are under threat in a number of lakes throughout Canada and the northern United States. As a result, the General Status of Alberta Wild Species report lists them as a Sensitive species.