USFWS Logo U.S. Fish and Wildlife Service Banner
The Mountain-Prairie Region


U.S. Fish and Wildlife Service
134 Union Boulevard
Lakewood, Colorado 80228


Robert Muth                  ENDANGERED FISH             Ralph Morgenweck
Program Director
                RECOVERY PROGRAM
                              Regional Director

Recovery Program Implementation Committee
U.S. Fish and Wildlife Service - P.O. Box 25486 * Denver Federal Center - Denver, CO 80225 - (303) 969-7322 - Fax (303) 969-7327
U.S. Fish and Wildlife Service * U.S. Bureau of Reclamation * Western Area Power Administration - Colorado * Utah - Wyoming
Environmental Defense Fund e National Audubon Society - Colorado Wildlife Federation - Wyoming Wildlife Federation
Colorado Water Congress - Utah Water Users Association * Wyoming Water Development Association * Colorado River Energy Distributors Association

April 14, 2003

Debbie Felker, Recovery Program,   303-969-7322, ext. 227
Matthew Andersen, UT Division of Wildlife Resources 801-538-4756
Mark Hadley, UT Division of Wildlife Resources,  801-538-4737


LAKEWOOD, Colo. – The Upper Colorado River Endangered Fish Recovery Program will focus on northern pike, smallmouth bass and channel catfish in an experimental nonnative fish management project this spring and summer to determine if populations of these species in certain river reaches in Colorado and Utah can be reduced to a level that will enable endangered and other native fishes to coexist and thrive.

Biologists believe these nonnative fish species pose a significant threat to the endangered humpback chub, bonytail, Colorado pikeminnow and razorback sucker.

In Utah, work is currently underway on the Duchesne River and the White River in the northeastern part of the state. A more extensive project will take place from mid-July through mid-August in the Desolation and Gray canyons of the Green River. Detailed information about the Green River project will be presented at public Regional Advisory Council meetings May 19 in Vernal and May 20 in Green River. Those with questions may also call Utah Division of Wildlife Resources offices in Vernal, Moab and Salt Lake City.

"Nonnative fish have been identified as one of the factors limiting recovery of the native fish of the Colorado River Basin, including the Green River in Utah," said Matthew Andersen, native aquatic species coordinator for the Utah Division of Wildlife Resources. "Many researchers have identified nonnative fish as a threat to natives because they prey on native species, especially young natives. The nonnative fish also compete with the natives for food."

In the Green River and its tributaries, channel catfish and northern pike are especially harmful.

Both species are aggressive predators who can consume many native fish in their lifetime," he said. "Because the native fish did not evolve in a system that included these predators, they don’t have the natural defense mechanisms needed to help them survive."

Andersen says it is unlikely all of the nonnative fishes could ever be removed from such an extensive system, but biologists hope active removal efforts will help native fish produce offspring, and that the offspring will have a greater chance of surviving in a habitat with fewer nonnative fish.

The recently approved recovery goals for the endangered fish of the Colorado River Basin recognize that removal of some of the nonnative fish will likely be required if endangered native fish are to recover. Other native fishes are also expected to benefit from this experiment, including roundtail chub, bluehead and flannelmouth suckers and speckled dace.

Three Recovery Program partners – the states of Colorado and Utah and the U.S. Fish and Wildlife Service (FWS) – will conduct the work in 438 miles of river in the Upper Colorado River Basin in Colorado and Utah. Biologists from Colorado State University (CSU) will also participate with the work in Colorado.

In eastern Utah, biologists will establish experimental treatment and control sections in the Green River in Desolation and Gray canyons, on the Duchesne River between Myton Diversion and the Green River confluence and the White River (in Uintah County) from the Colorado state line to the Green River confluence.

In treatment sections, targeted nonnative fish species will be removed. In control sections, targeted nonnative fish species will be captured, marked or tagged and returned to the river.

Similar efforts will take place on the Yampa, Colorado and White rivers in western Colorado.

Follow-up sampling will determine if management efforts reduced the numbers of targeted nonnative fishes in sections where they were removed. Monitoring of endangered and other native fishes will determine if numbers of these species increase.

"This research will help identify the level of management required to minimize the threat of nonnative fishes to the endangered fishes to satisfy criteria needed to recover these species," said Recovery Program Director Robert Muth. "We will assess the data each year to determine future nonnative fish management actions."

Nonnative fish management is only one of several actions the Recovery Program is implementing to meet its goal of recovering the endangered fishes. Efforts are also ongoing to provide river flows, restore habitat, construct fish ladders and screens, produce and stock endangered fish and monitor results.

"Restoration of native fishes to Western states not only benefits native fish populations and their stream environment, but also provides us with a means to protect Utah’s water use and right to develop additional waters," said Bob Morgan, executive director of the Utah Department of Natural Resources. "The program was developed and implemented to avoid the potential of curtailed water storage and use in the Upper Colorado River Basin. Utah’s participation brings us closer to recovering federally listed species, reduces the likelihood that other native fish will need to be listed and helps us comply with provisions of the Endangered Species Act."

Established in 1988, the Upper Colorado River Endangered Fish Recovery Program is a voluntary, cooperative program involving state and federal agencies, environmental groups and water and power user organizations in Colorado, Utah and Wyoming. Its purpose is to recover the endangered fishes while water development proceeds in accordance with federal and state laws and interstate compacts. For more information, visit the Recovery Program’s website: or call 303-969-7322, ext. 227.



Email Us:

FWS Mountain-Prairie Region Press Releases

FWS Mountain-Prairie Region Home Page FWS National Website
Privacy Department of the Interior FirstGov
Freedom of Information Act (FOIA)
Who We Are Questions/Contact Us