Colorado cutthroat trout, the state's only native trout, is making a comeback in the headwaters of Hermosa Creek.
The fish, also native to Utah, Wyoming and New Mexico, is found in only about 14 percent of its historic habitat, said Clay Kampf, a San Juan National Forest biologist.
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 it, and the area in the Hermosa Creek drainage will be one of the largest, said Jim White, a Colorado Parks and Wildlife biologist.
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 headwaters were home to brook trout, not cutthroat.
But since then, the cutthroat 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.
In early August, Colorado Parks and Wildlife, Trout Unlimited and the Forest Service will begin establishing the fish in three miles of Sig and Relay creeks. Non-native fish will be removed, and the cutthroats added.
The Forest Service will build waterfalls to prevent non-native fish from getting into cutthroat habitat, Kampf said.
Currently, areas designated as cutthroat habitat are catch-and-release.