Trout of the North

Most of the trout found in Frederick County are small to medium-sized fish that inhabit cold, swift-flowing streams or brooks. Trout such as the introduced rainbow and brown trout or the native brook trout are the species you will find in our area.

If you travel far enough north, however, you may enter the range of the lake trout. As their name implies, lake trout, also called togue, mackinaw or gray trout, are normally found in deep, cold, well-oxygenated oligotrophic lakes in the northern parts of the U.S., Canada and Alaska.

There are three main families of salmonids: trout, char and salmon. Lake trout belong to the char family of salmonids, which includes our native brook or speckled trout, Dolly Varden trout, bull trout, blueback trout and Arctic char. The main characteristic that differentiates char from the true trout is that char have light spots on a darker background, while trout have dark spots on a light background.

Lake trout are bluish-gray to greenish with white to yellow spots on their skin. They have a deeply forked tail and soft, oily skin. Lake trout are the largest-growing freshwater trout. They can live up to 40 years and grow to sizes in excess of 50 pounds. The largest lake trout caught on rod and reel weighed 72 pounds, while a mammoth 102-pound trout was caught in a gill by a commercial fisherman. Lake trout are prized as game fish and as table fare. They spawn in the fall with the eggs hatching the following spring. Sometimes lake trout will hybridize with speckled (brook) trout to produce a hybrid known as a splake.

Lake trout are sensitive to water temperature; they prefer temperatures in the range of 45 to 55 degrees Fahrenheit. During the colder times of the year, lake trout can be found in relatively shallow water, but once water temperatures rise, these fish lie in the deeper sections of the lake, often times inhabiting depths of 100 to 200 feet below the surface. These cold clear lakes are not nutrient rich and much of the food source does not venture into these deeper areas. As a result lake trout often grow slowly and do not become mature until 8 to 10 years of age.

This slow growth and low reproduction rate make lake trout very susceptible to heavy fishing pressure. Lake trout were once quite common in the Great Lakes, but commercial fishing pressure, combined with the introduction of lamprey eels and pollution, severely affected their numbers. Now that lampreys are under control and the water is less polluted, the lake trout are making a comeback, especially in Lake Superior, where a vibrant sport fishery exists for these large trout.

Article by FCFCDB

Nature Notes for 9/9/2012