Colorado cutthroat trout is making a comeback in the headwaters of Hermosa Creek.
The fish, native to Colorado, Utah, Wyoming and New Mexico, is now found in only about 14 percent of its historic habitat, said Clay Kampf, a fisheries biologist for the San Juan National Forest.
The cutthroat was hurt by competition from non-native brook trout and a tendency to hybridize with rainbow trout.
Now, there are efforts across Colorado to re-establish the fish. The area in the Hermosa Creek drainage will be one of the largest when it is finished, said Jim White, an aquatic biologist with Colorado Parks and Wildlife.
The presence of the fish helped local advocates push through the legislation designating the Hermosa Creek Wilderness and Special Management Area. Both areas encompass more than 100,000 acres north-northwest of Durango.
In 1991, Hermosa Creek headwaters were home to brook trout, not cutthroat.
But since then, the species has been re-established in 17 miles of the east fork and the main stem of the headwaters, Kampf said.
When the project is complete, the fish will occupy 23 miles of creek upstream from the confluence of the east fork and the main stem.
“We’re making substantial progress,” he said.
In early August, Colorado Parks and Wildlife, Trout Unlimited and the Forest Service are going to start work on establishing the fish along three miles of Sig and Relay creeks.
To re-establish the fish, all the non-native fish are removed from the stream, and the cutthroats are introduced.
The Forest Service must also build waterfalls to prevent non-native fish from getting into cutthroat habitat, Kampf said.
“Colorado cutthroat do not compete with non-native fish at all,” White said.
Currently, all areas designated as cutthroat habitat are catch-and-release, and the Forest Service is considering other changes to help protect habitat.
Installing culverts in areas where people and vehicles are crossing the creek could limit the amount of sediment in the water.
These improvements could be written into the Hermosa Wilderness and Special Management Area plan.
An early version of this story incorrectly said the Colorado cutthroat trout was the only native trout in Colorado. The greenback cutthroat trout and the Rio Grande cutthroat trout are also native to Colorado.