Brown Trout
central mudminnow

What's In a Name?
Brown trout: refers to the overall color of the trout

Salmo (sal´-moe) means "salmon of the Atlantic" in Latin
trutta (trutt´-tah) means "trout" in Latin

Where Do They Live?
Brown trout are not native to North America. They were introduced in the eastern USA in 1883 and probably into Minnesota not to long afterward. They were introduced into many of Minnesota's stream by 1923. Today, they occur in many of Minnesota's cold-water streams and lakes and also in Lake Superior. Some of these streams and lakes have reproducing populations in them. Others are restocked every few years. Brown trout can live in warmer and more turbid (cloudier) water than brook trout can. This allows them to live in the downstream portions of coldwater streams, while brook trout live in the headwaters. Brown trout frequently are found living with blacknosed dace, mottled sculpins, white suckers, creek chubs, common shiners, northern brook lampreys, and American brook lampreys.

How Big Do They Get?
How Long Do They Live?

Brown trout grow fairly rapidly until they reach maturity. Then they slow down a bit. In Minnesota, brown trout 250-380 mm (10-15 in) long and 1.6-2.5 kg (3.5-5.5 lbs) are fairly common in streams. Stream browns over 635-mm (25-in.) long and 5.5 kg (12 lbs) are rare, but in Lake Superior they are often bigger. The Minnesota state record for this fish is 7.56 kg (16-lbs. 12 oz). Because brown trout are somewhat resistant to the pressures of fishing, they can easily get to 5-7 years old.

What Do They Eat?
The brown trout is a very active feeder and it eats a great variety of foods. It commonly feeds upon land and water insects, zooplankton, worms, crayfish, small clams, snails, and a variety of small fish (young trout, sculpins, minnows, and darters). In a few strange cases, large browns have been known to eat young mink and small turtles.

What Eats Them?
The main predators for this secretive trout are bigger trout and humans. Because of their good taste, size, fighting ability, and the challenge in getting them to bite, brown trout have become a favorite of many anglers. Small brown trout are occasionally preyed upon by otters, mergansers, and in some cases water snakes.

How Do They Reproduce?
Unlike Pacific salmon, brown trout do not die after spawning. Most will spawn multiple years and often near the same place. Spawning habits and seasons are similar to the brook trout, except that brown trout take 3-4 years to mature. Brown trout spawning season begins in October and goes into December. If there are no barriers as there are in many North Shore streams, brown trout swim up into headwater areas to spawn. They usually choose gravel bottoms often where there are spring seeps and good moving water. The fish pair up and them the female makes a saucer-shaped depression in the gravel. The male defends the nest after it is built until the female is ready. Once the female is ready, she drops into the nest and the male follows her. Here the female lays the eggs and the male fertilizes them at the same time. The female then covers the eggs with the gravel she removed to build the nest. The two will repeat the process until the female is "spent" (has laid all of her eggs). After spawning, the parent fish move back to the water from which they came.
A single female can lay 400-2,000 depending on her size.

Conservation and Management
Brown trout is an exotic species that has become self-sustaining in some stream and maintained by repeated stocking in others.

Natural History of Minnesota Fishes

Photograph by John Lyons WiDNR
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program