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VERNAL — For the third straight year, state wildlife biologists will use a substance found in tropical plants to kill off invasive fish species in an effort to help a native fish species thrive in the High Uintas.
The Utah Division of Wildlife Resources plans to use rotenone at a handful of waterbodies on the north slope of the High Uintas later this month. The plan is to treat the East and West forks of Carter Creek above Sheep Creek canal, as well as Bummer, Mutton and Ram lakes between Aug. 17 and Aug. 25.
The substance is toxic for fish but doesn't impact people, pets or other wildlife when used properly. It's used to remove invasive fish species, especially as those fish start to weed out native fish species.
In this case, the plan is to remove brook trout that threaten to completely replace Colorado River cutthroat trout in the affected bodies of water. Biologists say that without the treatment, brook trout would take the place of the native cutthroat trout species within the next 20 years and put it on the path to end up protected by the Endangered Species Act.
"The activities will protect the (Colorado River cutthroat trout), while also providing people with great areas to fish for these native fish," said Bryan Engelbert, a regional sportfish biologist for the division, in a statement Monday.
Anthony Christianson, a regional Wildlife Recreation Specialist for the division, added that the treatment areas and any land within 20 feet of the water will be closed off before the treatment program begins. It'll reopen after the treatment ends.
State wildlife biologists performed similar rotenone treatments in the north slope area in 2019 and 2020. Officials said it normally takes two or three treatments for the program to be successful in helping restore cutthroat trout. Since this is the third treatment at East Fork Carter Creek, biologists plan to stock Colorado River cutthroat trout there by early October at the latest.
Biologists also plan to restock Colorado River cutthroat trout at Ram and Mutton lakes next year, while West Fork Carter Creek and Bummer Lake will not be restocked until 2023 at the earliest.