Since their introduction into Colorado in the late 19th century, brown trout have established wild and self-sustaining populations throughout hundreds of miles of rivers and creeks. They occur today in nearly every mountain stream between 6,000 and 10,000 feet in elevation. In addition to the more accessible rivers and mountain reservoirs, where they can grow to trophy sizes, vibrant populations of wild browns provide sport-fishing opportunities for backcountry anglers.
The largest brown trout caught in Colorado weighed 30 pounds, 8 ounces. Although it was caught at the Roaring Judy Ponds, located at the state fish hatchery near Almont, it probably swam up the Gunnison River from Blue Mesa Reservoir. Blue Mesa is known for producing trophy-sized brown trout.
A Gift of Eggs
The earliest documented brown trout in Colorado arrived from England in 1885, shipped as eggs to a Denver hatchery. In 1890, U.S. Senator Henry M. Teller received a gift of brown trout eggs from Loch Leven in Scotland and donated them to the state. Also during this period, brown trout from Germany were being raised in 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.
Despite the notion that they are difficult to catch, brown trout have won the hearts of 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, the brown trout survived. In the absence of the rainbows, brown trout populations flourished.
Catching Brown Trout
To catch brown trout consistently, anglers must take the cautious nature of the species into consideration. Browns could be the poster fish for skittish trout, racing 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 scare them into hiding.
Stealth is important, but the 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.
Brown Trout Spawn
Brown trout spawn in September and October. The females move onto shallow, gravel riffles and dig redds in the gravel by fanning their tails. As the females deposit their eggs in the redd, the males posture themselves alongside them to fertilize the eggs. Spawning redds are usually visible from shore, and anglers should avoid wading in these areas or otherwise disrupting the spawning process.
While most brown trout populations remain wild and self-sustaining, Colorado Parks and Wildlife bolsters some populations with sub-catchable brown trout raised in fish hatcheries.