Lake Trout

Lake Trout

NPS

Characteristics
Lake Trout (Salvetinus namaycush), also known as mackinaw or lake char, are a cold water loving member of the salmon family. They have white to yellow spots on a green to grayish body that pales to a white belly. The dorsal, adipose, caudal and anal fins are spotted and darker colored in yellow to browns. The paired pectoral and pelvic fins and sometimes the anal fin as well tend to be orange-red with a narrow white edge. The torpedo shaped body ends in a forked tail. Breeding males develop a dark lateral stripe on their sides.

Did You Know

• Lake Trout may reach a life span of around 25 years.
• The average adult Lake Trout may weigh nine to ten pounds, but some grow to the 30-50 pound range. Lake Trout that eat other fish are the ones that grow into the larger sized fish.
• The record Lake Trout was 102 pounds. The size is definitely determined by the diet.
• Lake Trout that feed on plankton and insects only weigh two to three pounds. In April and May they may feed upon the minnows, crayfish and insects abundant in the shallow parts of a lake.
• As the water warms up, the Lake Trout are forced into the deeper parts of a lake because they need to be in the colder water. But the deeper water does not provide nearly as much for them to feed on.

Spawning Habits
When Lake Trout reach sexual maturity at around six to seven years of age they will spawn at night on rocky shoals in the fall during late October or November. Some will return to the same spawning beds year after year. The fertilized eggs will settle within rocky crevices and in the gravel where they stay through the winter until they hatch about four to six months later during March and April. Some of the spawning will occur in deeper waters.

Territory
Lake Trout are native to Canada and Alaska and south into the United States throughout New England and the Great Lakes. That is in keeping with their preference for cold water especially with lots of dissolved oxygen. The water they like is often found just at greater depths. They have been introduced into parts of Europe and South America as well as Asia.

Prey And Predator
Lake Trout were once commercially fished in the Great Lakes until invading, non native sea lampreys in the 1950s and 1960s, over harvest and pollution reduced their numbers significantly. Even with restocking programs, they have not returned to their former numbers. But don’t feel sorry for Lake Trout for in some waters they are the invading (illegally introduced) non native, undesired predatory fish species wrecking havoc on native populations.

Luckily Bighorn Lake does not have a problem. In Yellowstone Lake though Lake Trout have taken to feeding on the native Yellowstone Cutthroat Trout and reduced their number to less than 10%. The animals that feed on the Cutthroat like the grizzly bear, otters and eagles are also greatly affected as well as they do not or cannot get to the Lake Trout in the deeper waters. Now if we could just ship the Lake Trout back to the Great Lakes…or maybe a volcanic eruption into the deeper waters of the lake!