MAMMOTH HOT SPRINGS, WY – Starting next week, park staff will take action to eliminate non-native rainbow trout, brook trout, and lake-dwelling grayling from the upper Gibbon River drainage. After the action is complete, biologists will reintroduce native fish species to the upper Gibbon River drainage.
The upper Gibbon River drainage is in the central portion of Yellowstone National Park and includes Grebe, Wolf, and Ice lakes, as well as the connecting streams above Virginia Cascades (which is located approximately 0.75 miles north of the Grand Loop Road between Norris Junction and Canyon Village).
Beginning on Monday, August 21 and continuing through September 30, biologists will use rotenone, a piscicide (fish toxin) to remove fish in the upper Gibbon River drainage. Rotenone is a naturally occurring chemical compound derived from the roots of certain tropical plants. Biologists will add potassium permanganate to water at the lower bounds of the upper Gibbon River drainage to fully detoxify rotenone and prevent impacts to downstream waters.
Trails and campsites within the upper Gibbon River drainage will be closed to public access (see map for details). The Ice Lake area will be closed from August 21 to September 30. The Grebe and Wolf lake area will be closed from September 5 to 30.
This action is part of a three year project that will create a refuge for the reintroduction of native westslope cutthroat trout and fluvial (stream-dwelling) arctic grayling, which are the park’s native grayling strain. Genetically pure westslope cutthroat trout and fluvial arctic grayling were nearly eliminated from Yellowstone because of the historical stocking of non-native fish. The park has restored these native fish to East Fork Specimen Creek, Goose Lake, and Grayling Creek as outlined in our Environmental Assessment and Finding of No Significant Impact documents about the Native Fish Conservation Plan. The work in the upper Gibbon River drainage is a continuation of this effort.
Learn about fisheries science in Yellowstone National Park, visit go.nps.gov/yell_fisheries_science.