Colorado River cutthroat trout
(Oncorhynchus clarki pleuriticus)

Historic Range: The most spectacular of the colorful cutthroat trout and one of the most beautiful fish in North America, the Colorado River cutthroat trout historically occurred in most cool water habitats of the Colorado River drainage in Colorado, southern Wyoming, eastern Utah, and extreme northwestern New Mexico and northeastern Arizona.

Habitat requirements: Like most members of the trout family, Colorado River cutthroat trout require clear, cold water, naturally-fluctuating flows, low levels of fine sediment in channel bottoms, well-distributed pools, stable streambanks, and abundant stream cover.

Current population status: These trout are extremely imperiled. The Colorado River cutthroat trout currently occupy approximately five percent of its historic range, primarily in isolated, small headwater streams. Conservation populations--those with a high degree of genetic integrity--are estimated to only occupy less than one percent of these trout's historic range, as documented in the Western Native Trout Campaign's report: Imperiled Western Trout and the Importance of Roadless Areas. The same report estimates that about 62% of the remaining conservation populations of these trout are associated with roadless areas, clearly indicating that the full protection of roadless areas is vital to the persistence of these spectacular, and highly endangered, native trout.

Threats to continued persistence: The severe contraction in the Colorado River cutthroat trout's range was primarily caused by the stocking and spread of non-native trout, and habitat loss due to livestock grazing, water diversion, logging, roads, mining and other factors, which degrade stream conditions required by these trout.

Listing Status (as of 5/02): The Center for Biological Diversity and a coalition of groups filed a petition to list the Colorado River cutthroat trout as endangered in December, 1999. In response to lack of action on the part of the U.S. Fish and Wildlife Service, the Center for Biological Diversity, Biodiversity Legal Foundation, Biodiversity Associates, Center for NAtive Ecosystems, and Colorado Wild filed suit in January, 2001 to force the agency to process the petition. The court has failed to make a decision on the case and in March, 2002, we filed a new motion to bring it to the courts attention.