Native fish reintroduction work continues on Yellowstone’s upper Gibbon River

MAMMOTH HOT SPRINGS, WY – Starting the week of August 20, park staff will continue a project to eliminate nonnative fish from the upper Gibbon River drainage. Once nonnative fish are removed, biologists will reintroduce native fish species to the streams in this area.

From August 20 through August 26, biologists will remove nonnative rainbow trout and brook trout in the upper Gibbon River drainage using the fish toxin rotenone. Rotenone is a naturally occurring chemical compound derived from the roots of tropical plants. Below the treatment area biologists will add potassium permanganate to the water to remove the effects of rotenone and prevent impacts to downstream waters. To ensure the removal of nonnative fish, these treatments will be repeated in 2019 and, if needed, 2020. Reintroduction of native fish would begin in 2021.

The upper Gibbon River drainage is in the central portion of Yellowstone National Park and includes streams that flow out of Grebe, Wolf, and Ice lakes. The Wolf Lake Trail and Virginia Cascades Drive will be closed to the public during this project.

This work continues the park’s efforts to create refuges that support the reintroduction of native westslope cutthroat trout and fluvial arctic grayling, the park’s native grayling strain. The historic stocking of nonnative fish nearly eliminated these species from Yellowstone. In recent years the park has restored them to the East Fork of Specimen Creek, Goose Lake, and Grayling Creek. Planning documents describing this work can be found on the National Park Service planning website.