CMC's Denver Fly Fishing Section
Colorado's Brown Trout
Meet the Browns
Dennis McKinney
Article published 10/10/07 in the Outdoors Journal of the Colorado Division of Wildlife

Brown trout, Salmo trutta are widely distributed in Colorado, with self-sustaining populations occurring in nearly every mountain stream and body of water between 6,000 and 10,000 feet in elevation. Although not native to the western United States, brown trout are now well established throughout the Rocky Mountains.

Since their introduction into Colorado in the late 19th Century, brown trout have established wild and self-sustaining populations in hundreds of miles of rivers and creeks. These vibrant populations of wild trout are the primary source of sport fishing opportunities to anglers in the backcountry, and they also are favorites of anglers at large reservoirs, where they can grow to trophy sizes.

The largest brown trout caught in Colorado weighed 30 pounds 8 ounces. Although the fish was caught in Roaring Judy Ponds located at the state fish hatchery near Almont, it probably swam there via the Gunnison River from Blue Mesa Reservoir. Blue Mesa is known for producing trophy-sized brown trout.

Brown trout first arrived in the northeastern United States from Germany in 1883. German fish culturist Baron Lucius von Behr shipped 80,000 brown trout eggs to Fred Mather, an American angler, writer, and fish culturist that von Behr had met at the International Fisheries Exposition in Berlin. Von Behr continued to ship the red-spotted brown trout from Germany, but during this period, black-spotted brown trout also were arriving in the US from Loch Leven, Scotland.

The earliest documented brown trout in Colorado came via England in 1885, shipped as eggs to a Denver hatchery. In 1890, U.S. Senator Henry M. Teller received a gift of eggs from Loch Leven and donated them to the state. During this same time, von Behr brown trout were being raised at a Leadville hatchery. A century later, the brown trout tugging on angler’s lines are a mixture of those strains from Germany, Scotland, and England.

Brown trout are identified by the overall brown or dark golden hue of their body. The belly is usually white or cream colored except during spawning, when it turns a deep yellow. Large black spots cover the upper half of the body, from head to tail. Haloed red spots are present on the lower half of the body. Brown trout have square tails, not forked as with brook trout.

Despite the notion that they are difficult to catch, brown trout have won the hearts of many Colorado anglers. When whirling-disease swept through the state in the 1990s, wiping out  populations of rainbow trout and forcing the closure of fish hatcheries, brown trout came to the rescue. Having evolved with the parasite in Europe, brown trout can carry whirling disease but are less affected than rainbow trout. In the absence of the rainbow trout, brown trout populations flourished.

Are wild brown trout difficult to catch? No.

Are they more difficult to catch than rainbow trout? Maybe.

To catch brown trout consistently, anglers must take the wary nature of the species into consideration. Brown trout could be the poster fish for skittish trout, bolting for cover at the slightest hint of danger. Heavy footsteps on the bank, a fly line slapping the water, or an angler’s shadow cast across the water will send them darting for cover into the dark recesses of an undercut bank or the bottom of a pool.  Consequently, stealth is a major factor when stalking brown trout, especially large ones. Keeping a low profile, careful wading, and walking softly beside the stream are essential.

Stealth is important, but presentation and choice of flies and lures is a close second. After growing to a length of 12-inches or so, browns often develop different eating habits. In addition to their regular rations of aquatic insects, they begin to take larger prey such as minnows, small trout, crustaceans, and even mice that fall into the water. Although larger browns will rise to the surface for hatching insects or grasshoppers, the majority of their forage is taken beneath the surface.

In larger rivers such as the Arkansas, Gunnison, Colorado, and Rio Grande, brown trout typically hold within a few feet of the bank. Streamer flies such as Bead-head Woolly Buggers, Zonkers, and Clouser Deep Minnows cast to the bank and stripped back quickly will usually draw a strike if a brown is nearby.

In meandering valley streams, one tactic is to fish downstream with a weighted streamer, letting the fly swing in under cut banks and close to cover, and then retrieving it slowly.

Spin fishers should work upstream, approaching from behind the trout, looking for deep water near the bank, and casting their spinners into likely looking spots.

Brown trout spawn in streams throughout the state in September and October. The females move onto shallow, gravel riffles and dig redds [nests] in the gravel by fanning their tails. As the females deposit their eggs in the redd, the males posture themselves alongside the females to fertilize the eggs. Spawning redds are highly visible from shore, and anglers should avoid wading in these areas.

While most brown trout populations remain wild and self-sustaining, the Colorado Division of Wildlife bolsters some populations with sub-catchable brown trout raised in hatcheries.

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