MAMMOTH HOT SPRINGS, WY – From September 2-13, 2019, the following areas of the Upper Gibbon river drainage in the central portion of Yellowstone National Park will close for fisheries work:
- Virginia Cascades Drive
- Wolf Lake Trail
- Wolf Lake Cutoff trail (to Ice Lake)
- Areas of the backcountry to the north and south between Canyon and Norris Junctions (see map).
All campsites in the area will remain open. Closures may lift if the project is completed ahead of schedule.
Closures are necessary for park staff to continue work on a project to eliminate nonnative fish from the upper Gibbon River drainage, which drainage includes streams that flow out of Grebe, Wolf, and Ice lakes. Once nonnative fish have been removed, biologists will reintroduce fish species to the streams in this area.
Biologists will remove nonnative rainbow trout and brook trout 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 may be repeated in 2020. Reintroduction of fish will begin in 2020 or 2021.
This work continues the park’s efforts to create refuges that support the introduction of westslope cutthroat trout and Arctic grayling. The historic stocking of nonnative fish nearly eliminated these species from Yellowstone. In recent years, the park has attempted to restore 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.