GREEN RIVER — Conservationists are suing federal wildlife officials again in an effort to gain endangered-species protections for the Colorado River cutthroat trout, found only in Wyoming, Utah and Colorado.

The federal lawsuit was filed Tuesday in Washington, D.C., by the Oregon-based Center for Biological Diversity, said spokesman Noah Greenwald.

The suit challenges a 2007 decision by the U.S. Fish and Wildlife Service that kept the fish off the endangered-species list.

The agency’s decision at the time said there was evidence of an increased number of populations of the fish.

But Greenwald said the decision to not list the fish for special federal protections relied on a “flawed” Bush-era policy that allowed the Fish and Wildlife Service to look only at its current range when considering whether the trout is endangered.

He said the agency’s decision conflicts with Endangered Species Act provisions, which state that a species need not be at risk of extinction globally to receive protections.

Greenwald said the trout has been lost from about 87 percent of its historic range, which includes parts of New Mexico and Arizona.

He said the fish continues to face threats from habitat degradation, nonnative trout species and increasing climate change.

The Colorado River cutthroat trout is the only salmonid native to the upper Colorado River basin. The fish 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.

Substantial increase

The Center for Biological Diversity and other environmental groups petitioned the federal government in December 1999 to list the Colorado River cutthroat trout as threatened or endangered.

After the Fish and Wildlife Service said the petition failed to present substantial information indicating that listing the subspecies was warranted, the group filed a complaint alleging that incorrect standards and procedures were used to assess the petition.

In September 2006, a federal court ruled in favor of the center and ordered the government to produce a status review and a 12-month finding for the fish.

In June 2007, USFWS officials determined in the status review that listing the fish as threatened or endangered was not warranted.

The agency said it found no evidence of major declines in the overall distribution or abundance of the Colorado River cutthroat trout over the past several decades.

Federal biologists concluded there was actually evidence of a “substantial increase” in the number of known populations.

The last agency rangewide status report of the fish estimated that at least 285 Colorado River cutthroat trout populations collectively occupy approximately 1,800 miles of stream habitat in 42 watersheds in Wyoming, Colorado and Utah.

Contact Jeff Gearino at gearino@tribcsp.com or 307-875-5359.