Brown Trout Incentivized Harvest

The Brown Trout Incentivized Harvest has been discontinued and, due to current program limitations, we do not anticipate being able to restart it in the near future.



 
 
Chart indicating rapid rise of brown trout population in Colorado River 1991-2023.
Index of brown trout abundance (mean fish caught per minute of electrofishing) in Lees Ferry, 1991-2023. The closed circles show the mean value; the whiskers show the 95‐percent confidence intervals.

AZGFD / David Rogowski

History of Fishing on the Colorado River Upstream of Lees Ferry


Before Glen Canyon Dam was built, the Colorado River flowed muddy and warm with great seasonal changes for eons and developed a community of native pikeminnows, suckers, and chubs with unique adaptations for utilizing that habitat. The hydrology and the physical and chemical makeup of the Colorado River completely changed when the dam was completed in 1963. The clear, cold water released from Glen Canyon Dam provided excellent conditions for a rainbow trout fishery. Hatchery raised rainbow trout were initially stocked in the 1960s thru the 1990s after dam completion. They eventually became a self-reproducing population. Arizona Game and Fish Department (AGFD) also experimentally stocked other trout and salmon species until it was determined that rainbow trout were best suited for the tailwater stretch of the river below the dam.

In 1981, AGFD designated the 15-mile stretch of the Colorado River below Glen Canyon Dam to Lees Ferry as a Blue Ribbon Rainbow Trout Fishery. Glen Canyon National Recreation Area manages the area as a high-valued recreational rainbow trout fishery.

Although stockings of brown trout below the dam were not self-sustaining and were eventually discontinued by AGFD in the mid-1980s, small populations of brown trout in Grand Canyon National Park that were stocked in the 1920s continued to reproduce and thrive in cold water tributaries of the Colorado River downstream. These brown trout populations spread out into the river and began to have a big impact on the endangered humpback chub population at the mouth of the Little Colorado River. In the early 2000s an extensive electrofishing effort was made by a host of agencies in order to reduce that particular brown trout population. Between 1984 and 2013, rainbow trout comprised about 97% of the fish population between the dam and the Paria River Riffle while brown trout only comprised about 2%. However, since 2014 brown trout have begun to successfully spawn and now make up over 10% of the fish population.

Non-native fish in Glen Canyon.

 

The Threat

The Colorado River below Glen Canyon Dam is home to native fish species like flannelmouth and bluehead suckers. Two endangered fish species, razorback sucker and humpback chub, can also be found in the Marble and Grand Canyon stretches of the river. Native fish are highly susceptible to predation by fish eating predators like brown trout. As brown trout grow, they begin to feed heavily on other fish species. As sub-adults and adults brown trout are 17-times more likely to eat other fish than are rainbow trout. The increase in number of brown trout in Glen Canyon has raised concerns for fish managers. As the Glen Canyon brown trout population grows, they could migrate downstream and pose an immediate threat to native fish species like the endangered humpback chub. Brown trout are also able to thrive in warmer river water than rainbow trout and are better adapted to hunting other fish in the murky river water of the Colorado River when the Paria River and side canyons are flowing.

 

Know Your Trout

Spotted fish with words: Brown trout Spotted fish with words: Brown trout

Left image
I'm a Brown Trout
Credit: Image - Iowa DNR

Right image
I'm a Rainbow Trout
Credit: Image - Iowa DNR

  1. Spots – Brown Trout often have red-orange spots with many spots having a blue-gray “halo”; spots are large. Rainbow Trout have numerous black spots lacking a “halo”, spots are typically small.

  2. Tail – Brown Trout have few or no spots on their tail; Rainbow Trout have distinct radiating spots on their tail.

  3. Body – Brown Trout have a brown-yellow body. Rainbow Trout have a olive-bluish back; adults typically have noticeable pink sides.

 

Brown Trout Harvest Inventory

Number, size, and payout of brown trout caught by month.
Month Year Monthly Payout Top Angler Payout/Month No. Anglers Unknown Length Fish Harvested 6-12 inches Fish Harvest 12-18 inches Fish Harvest 18-24 inches Fish Harvested > 24 inches Total Number of Brown Trout Harvested Total Number of PIT tags returned
 
* Some fish were caught by NPS employees and not eligible for the reward.
 

For More Information Contact:

Jeff Arnold, Fisheries Biologist, National Park Service (928) 608-6266
Scott Rogers, Aquatic Program Manager, Arizona Game and Fish Department (928) 214-1245

Last updated: July 25, 2025

Park footer

Contact Info

Mailing Address:

PO Box 1507
Page, AZ 86040

Phone:

928 608-6200
Receptionist available at Glen Canyon Headquarters from 7 am to 4 pm MST, Monday through Friday. The phone is not monitored when the building is closed. If you are having an emergency, call 911 or hail National Park Service on Marine Band 16.

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