WILSALL – Montana Fish, Wildlife & Parks, in collaboration with the Custer Gallatin National Forest, will begin additional phases of an ongoing project to conserve native Yellowstone cutthroat trout in the upper Shields River watershed this summer.
Yellowstone cutthroat trout have declined throughout much of their native range primarily due to competition and hybridization with non-native trout species and habitat loss. Yellowstone cutthroat trout populations have especially declined in the upper Shields River watershed largely due to the invasion of non-native brook trout. To mitigate further decline and conserve Yellowstone cutthroat trout in the upper Shields River, FWP and the Custer Gallatin National Forest began removing brook trout in 2022.
This year, fisheries staff will continue removing brook trout from several tributaries to the upper Shields River. The project area is a stronghold for a core conservation population of Yellowstone cutthroat trout at high elevations and the northernmost extent of their range.
This year's phase of the project will begin next week. Work will take place in Dugout Creek and other areas of the upper Shields River basin.
Brook trout will be removed from the project area using a plant-derived fish toxicant called rotenone. Rotenone is routinely used in fisheries management and breaks down quickly in the aquatic environment. It offers an effective means of removing fish species that are incompatible with the management goals of a fishery without endangering the surrounding ecosystem. Crews will collect Yellowstone cutthroat trout from the project area before rotenone application and return them to the streams when the project is complete. Detoxification stations will be set up to ensure there are no negative effects to gill-breathing organisms downstream of the project area.
To provide for public safety and comply with the rotenone product label, the Custer Gallatin National Forest will issue a closure order during the time of the project. The closure will be in place Aug. 10 through Aug. 18. The entire upper Shields River drainage on National Forest System lands will be closed to recreational access during the treatment as indicated by the closure order and map, which can be viewed on the Custer Gallatin National Forest Alerts website.
FWP published an environmental assessment for this project in 2022, hosted public meetings and solicited public comments.