The Utah Division of Wildlife Resources is coordinating with the U.S. Department of Agriculture Forest Service to conduct waterbody treatments in the High Uintas to restore native Colorado River cutthroat trout. The initiative involves using rotenone to remove non-native fish from specific drainages, necessitating temporary closures of certain areas to ensure public safety during the process.
Targeted Waterbody Treatments
The restoration project targets two specific drainages in the High Uintas to bolster populations of native Colorado River cutthroat trout. According to the Utah Division of Wildlife Resources, biologists will conduct treatments in the Fall Creek drainage on the south slope of the mountains from Aug. 3 through Aug. 6. This specific area is scheduled to reopen to the public on Aug. 8.
Additional treatments are scheduled for the North Fork Sheep Creek on the north slope of the Uintas on Aug. 19 and Aug. 26. This North Slope effort is part of a broader initiative to treat the upper portions of streams connected to the Sheep Creek canal. The DWR noted that this marks the first year of treatment for the North Fork of Sheep Creek, while the Fall Creek drainage is entering its second year of treatment.
Safety and Area Closures
To protect public health and safety, the Ashley National Forest issued a formal order for a temporary area closure. From Aug. 4 through Aug. 6, 2026, the Forest Service prohibited entry into the area within 20 feet of Fall Creek and its associated tributaries, as well as Anderson and Phinney Lakes. This order was established to allow ground crews to work safely in and around the treated waters.
While water access is restricted, the DWR stated that all hiking trails and other access points will remain open to public use. The closures apply specifically to treated waters, prohibiting the public from entering the water or obtaining drinking water from sources within the treatment area. The DWR noted that treatment areas will be well-signed and will reopen once rotenone levels are no longer detectable in the streams.
The Role of Rotenone
The treatments utilize rotenone, a natural substance derived from the roots of a tropical plant in the bean family. While rotenone acts as a respiratory toxin to fish, the DWR emphasized that it is not dangerous to people, pets, or other wildlife when used in the extremely low quantities required for stream and lake treatments.
Biologists aim to remove non-native species, including brook trout, non-native cutthroat trout, and rainbow trout. The DWR warned that without such intervention, brook trout populations could completely replace native cutthroat trout in these areas in less than 20 years. The goal of the project is to create resilient populations of native trout and prevent the species from being listed under the Endangered Species Act.
Fish Salvage and Future Stocking
Because the North Fork of Sheep Creek currently holds a genetically pure population of Colorado River cutthroat trout, biologists will perform fish salvage efforts prior to the chemical treatment. This process involves removing all possible size classes of cutthroat trout and holding them onsite. Once the water has oxidized, these fish will be released back into the creek to repopulate the stream.
The success of these treatments will dictate future conservation steps. For the Fall Creek drainage, if this year's treatment is successful, the DWR plans to stock Colorado River cutthroat trout into both Phinney Lake and Anderson Lake in 2027.
Ecological and Angling Benefits
The restoration efforts serve both ecological and recreational purposes. DWR Regional Sportfish Biologist Carsen Hinkhouse said that while the Uinta Mountains host over 1,000 lakes and hundreds of miles of stream, these efforts are specifically targeted to ensure native Colorado River cutthroat trout remain on the landscape while providing diverse angling opportunities.
Recent surveys have indicated an increased preference among anglers for cutthroat trout. While the treatments remove brook trout, the DWR noted that anglers can still find them in thousands of other streams and lakes throughout the Uinta Mountains. The DWR plans to continue providing abundant angling opportunities for multiple species in the region.
Long-term Conservation Goals
The Division of Wildlife Resources noted that over the past 20 years, significant progress has been made in restoring Colorado River cutthroat trout in northeastern Utah. DWR Northeastern Region Aquatics Manager Natalie Boren stated that building robust and resilient populations across the landscape will help ensure the species persists into the future.
For those seeking more information, the DWR provides an interactive Fish Utah map for fishing opportunities. The DWR Vernal office can be contacted at 435-781-9453 for questions regarding the upcoming treatments.
