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The Mountain-Prairie Region


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


 August 8, 2003

Contacts:  Lynn Kaeding 406-582-717
                     Diane Katzenberger 303-236-7917 ext 408

 U.S. Fish and Wildlife Service Determines that Westslope Cutthroat Trout Should Not Be Listed As a Threatened Species Under the Endangered Species Act

After a thorough review of all available scientific information, the U.S. Fish and Wildlife Service has determined that the westslope cutthroat trout does not warrant listing as a threatened species under the Endangered Species Act because abundant, stable, and reproducing populations remain well distributed throughout its historic range.

The Service based its finding on information contained in a 1999 status review as well as a 2003 status update report prepared by the fish and game departments of the States of Idaho, Montana, Oregon, and Washington, and the U.S. Forest Service. That report confirms that westslope cutthroat trout populations currently occupy 33,500 of its historic stream miles (59 percent) in the United States and genetically pure populations inhabit approximately 3,500 stream miles (57 percent of tested stream miles; 10 percent of occupied miles) and may inhabit as many as 12,600 miles of stream in which no potentially hybridizing fishes occur.  Many of these genetically-pure populations of the fish are found in habitats protected by natural barriers preventing interbreeding with other trout subspecies.

While the Service acknowledges that only a small portion (about 18%) of existing westslope cutthroat trout populations have been genetically tested, the Service concluded that the sampling that has been accomplished clearly indicates that numerous, genetically pure westslope cutthroat trout remain today. 

On April 14, 2000, the Service published a finding that the westslope cutthroat trout was not likely to become either a threatened or endangered species in the foreseeable future.  Subsequently, American Wildlands and four other environmental groups filed a lawsuit arguing that the Service acknowledged hybridization as a threat to the species but included hybrids in the overall westslope cutthroat trout population without providing a justification.

The Court ruled in favor of the plaintiffs and ordered the Service to reconsider whether to list the westslope cutthroat as a threatened subspecies and to more thoroughly take into account the hybridization issue when making that decisionIn addition, the Court directed the Service to present its scientifically-based conclusion about the extent to which it is appropriate to include “hybrid” westslope cutthroat trout and fish of unknown genetic characteristics in the group of fish that we considered for listing. 

“The new genetics-based, comprehensive status update report prepared by our fellow conservation agencies provides the Service with the best available scientific information regarding the range-wide status of the westslope cutthroat trout and confirms our initial determination,” said Ralph Morgenweck, the Service’s Director of the Mountain-Prairie Region.  “It also provides definitive new information regarding the prevalence of hybridization in westslope cutthroat trout populations.”

The Service used the new status update report, as well as a position paper outlining conservation and management plans for cutthroat trout prepared by the fish and game departments for the States of Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming, to develop criteria for including hybrid westslope cutthroat trout stock in establishing population size.

Using these criteria, a westslope cutthroat trout is defined as having at least 80% westslope cutthroat trout genes (the level at which a fish would conform to the scientifically-defined physical characteristics of that cutthroat trout subspecies).  That percent of hybrid westslope cutthroat trout is not considered a threat to the continued existence of the subspecies, and will be considered as westslope cutthroat trout in assessing its status for potential listing under the ESA.

The status review also notes that 70 percent of the habitat occupied by westslope cutthroat trout lies on lands managed by Federal agencies.  Moreover, many of the strongholds for westslope cutthroat trout occur within roadless or wilderness areas or national parks, all of which afford considerable protection to the fish.  The U.S Forest Service and the Bureau of Land Management have adopted an inland native fish strategy that includes standards and guidelines to protect watersheds.  

As stated in the 1999 status review, the U.S. Forest Service, the National Park Service, and State game and fish departments reported more than 700 ongoing projects directed toward the protection and restoration of westslope cutthroat trout and their habitats. Recent information indicates that these important conservation efforts are ongoing and increasing.

“While not factored into our decision, the Service acknowledges the many conservation efforts conducted by our Federal and State partners on behalf of westslope cutthroat trout,” said Morgenweck.  “These conservation projects contribute to the certainty that westslope cutthroat trout can be conserved and preserved.”

The westslope cutthroat trout is bright yellow, orange, and red.  It is generally distinguishable from other inland subspecies of cutthroat trout by the particular pattern of black spots that appear on the body.  Westslope cutthroat trout were found historically in streams and lakes in the upper Columbia River basin of western Montana, northern and central Idaho, and southern British Columbia and Alberta; the upper Missouri River basin of Montana and northwest Wyoming; the upper South Saskatchewan River basin of Montana and Alberta; the Methow River and Lake Chelan drainages in Washington; and the John Day River drainage in Oregon. 

The Service published its finding in yesterday’s Federal Register.

For more information concerning the westslope cutthroat trout including Q&As, a fact sheet, and chronology, please visit our 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 95-million-acre National Wildlife Refuge System, which encompasses 542 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 69 national fish hatcheries, 64 fishery resource 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 governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.

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