Office of External Affairs
Mountain-Prairie Region


U.S. Fish and Wildlife Service
Mountain-Prairie Region
134 Union Boulevard
Lakewood, Colorado 80228

June 13, 2007


Patty Schrader Gelatt 970-243-2778 ext 26
Diane Katzenberger 303-236-4578

Colorado River Cutthroat Trout Will Not Be Listed Under the Endangered Species Act

The U. S. Fish and Wildlife Service has determined that listing the Colorado River cutthroat trout, found in Colorado, Wyoming, and Utah, as threatened or endangered under the Endangered Species Act is not warranted at this time.

The Service found no evidence of major declines in the overall distribution or abundance of Colorado River cutthroat trout over the last several decades and there is evidence of a substantial increase in the number of known populations. The Service will continue to monitor the status of the trout and support ongoing conservation activities.

In making this finding, the Service considered the best available scientific information and relied heavily on a rangewide status report provided by the Colorado River Cutthroat Trout Conservation Team. The Team is composed of biologists from Wyoming Game and Fish Department, Utah Division of Wildlife Resources, Colorado Division of Wildlife, the Bureau of Land Management (BLM), U.S. Forest Service, and the U.S. Fish and Wildlife Service.

The report describes the current rangewide status of the Colorado River cutthroat trout in the United States and was peer reviewed by five recognized experts in the field of fishery biology, conservation biology, and/or genetics. The results of the peer review found that the status report provided sound scientific data to use as the basis of this finding.

The rangewide status report found that at least 285 Colorado River cutthroat trout conservation populations collectively occupy about 1,796 miles of stream habitat in 42 watersheds in Colorado, Utah, and Wyoming.

A conservation population is defined per state standards as either genetically unaltered (i.e. core population) or slightly introgressed due to past hybridization (typically less than 10 percent) and possessing attributes worthy of conservation. The Service has adopted the state standards and considers all core and conservation populations to be Colorado River cutthroat trout and are referred to as conservation populations in this finding.

The greatest number of conservation populations occurs in the Upper Green and Upper Colorado Rivers. Most other conservation populations occur in the Yampa, Lower Green and Gunnison Rivers. Small conservation populations occur in the Lower Colorado, San Juan, and Dolores Rivers. According to the report, in recent years more Colorado River cutthroat trout populations have been discovered and other populations have been expanded or restored. Also, populations previously considered hybridized were found, through genetic testing, to meet the standards of conservation populations.

Most Colorado River cutthroat trout populations currently occupy lands administered by federal agencies with the majority occurring within national forests. The majority of occupied habitat is considered to be in fair, good, or excellent condition indicating current management practices are maintaining habitat conditions. All of the cooperating management agencies have increased their focus on the protection and restoration of conservation populations of Colorado River cutthroat trout in all currently occupied watersheds.

Oil and gas development has been accelerating over the last several years in Colorado, Utah, and Wyoming and could affect Colorado River cutthroat trout populations through increased land disturbance. However, the results of a mapping analysis provided by the BLM show very little overlap between oil and gas development sites and Colorado River cutthroat trout conservation populations as most populations occur at higher elevations where oil and gas activity is minimal. The BLM is implementing measures to protect Colorado River cutthroat trout habitat in areas where oil and gas development has been proposed.

The effects of whirling disease and other diseases on Colorado River cutthroat trout populations were evaluated for this finding. The majority of populations were judged to be at very limited risk from this threat as disease and pathogens are not known to exist in Colorado River cutthroat trout watersheds or because barriers are in place blocking upstream movement of fish that might introduce disease. Furthermore, most populations occur in cold water streams at high elevations where conditions conducive to whirling disease are unlikely to exist. All three states have developed management activities to protect the species populations from whirling disease.

In December 1999, the Center for Biological Diversity and others petitioned the Service to list the Colorado River cutthroat trout as threatened or endangered. After the Service published a finding stating that the petition failed to present substantial information indicating that listing the subspecies was warranted, the petitioners filed a complaint alleging the Service used incorrect procedures and standards to assess the petition. In September 2006, the Court ruled in favor of the plaintiffs and ordered the Service to produce a status review and 12-month finding for the Colorado River cutthroat trout by June 7, 2007. Today’s finding is in response to that Court order.

The Colorado River cutthroat trout is the only salmonid native to the upper Colorado River basin. It is distinguished by its red/orange slash marks on both sides of the lower jaws and relatively large spots concentrated on the posterior part of the body.

This finding is published in today’s Federal Register. For more information about the Colorado River cutthroat trout, please visit the Service’s web site at:

The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 97-million-acre National Wildlife Refuge System, which encompasses 547 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 69 national fish hatcheries, 64 fishery resources offices and 81 ecological services field stations. The agency enforces federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign and Native American tribal governments with their conservation efforts. It also oversees the Federal Assistance program, which distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.

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