The Ashley National Forest Service will close waters in the Oweep Basin in the Uinta Mountains to remove non-native fish from July 31 until Aug. 6.
The treatment is in preparation for the reintroduction of native Colorado cutthroat trout in the next few years.
Ashley Forest Service Public Affairs Officer Louis Haynes said non-native species the Utah Division of Wildlife Resources introduced for recreation purposes, like the brook trout and rainbow trout, have out-competed native fish and need to be culled.
Specifically, the Ashley National Forest Service will close the northeastern portion of the Lake Fork drainage: Porcupine Lake, Oweep Creek and its tributaries. Lands within 20 feet of the waterways will also be off limits.
National forest trails in the area, Highline Trail and Lake Fork Trail, will remain open.
Oweep Creek runs south and feeds the Lake Fork River, itself a tributary of the Duchesne River.
The closures are necessary because the forest service will use the chemical rotenone to treat the waters.
Rotenone occurs naturally in the roots of legumes and is commonly used to kill invasive fish.
Haynes said the rotenone will be methodically introduced and removed from the waterways.
“We do have an introduction station,” Haynes said. “And then downstream, at the end of the treatment site, we do have a detoxification station which nullifies the chemical as it runs on downstream.”
The forest service usually does one treatment per year, for two or three years in a row, before it reintroduces native fish.
Haynes said this year is the Oweep Basin’s first treatment, with more to follow.
