Brown Trout

Brown trout are a golden-brown to olive trout with large dark spots on the back and sides, often ringed with pale halos, and scattered red or orange spots along the flanks. The tail is squared and lightly spotted or plain, which separates them from the heavily spotted tail of a rainbow, and the adipose fin usually carries an orange edge. Lake-run and sea-run fish turn bright silver and can be mistaken for salmon; spawning males develop a hooked lower jaw and deep bronze color.

Native to Europe, western Asia and North Africa, brown trout were introduced to the US in 1883 from German and Scottish (Loch Leven) stock and now live in every state with cold water. They dominate many eastern freestone rivers, the big western tailwaters below dams, spring creeks from Pennsylvania to Montana, and the Great Lakes, where lake-run browns of 20 pounds and more return to tributaries each fall.

Browns are the most tolerant of warm and silty water among the trout, which is why they outcompete brookies in degraded streams, but they are also the most cautious. They hold tight to undercut banks, log jams and deep pools, feed heavily on insects as juveniles and switch to crayfish, sculpins, baitfish and even mice as they grow. Large browns are largely nocturnal and feed most on overcast days, at dusk and after dark. They spawn in fall on gravel riffles when water drops below about 50°F (10°C).

For anglers, the brown trout is the fish that built American fly fishing: match-the-hatch on spring creeks, streamer fishing for the big ones and the fall run on Great Lakes tributaries. Trophy fish over 10 pounds are realistic in the White, Little Red, Missouri and Niagara systems, and the current world record came from a New Zealand canal.