The Montana Department of Fish, Wildlife, and Parks has fully closed all water-based recreation on the Yellowstone River and its tributaries north of Yellowstone National Park’s northern boundary at Gardiner, Mont., because of an ongoing and unprecedented fish kill, according to a news release.

The department intends to limit the spread of a fish-killing parasite that causes the proliferative kidney disease, which has an 80 percent to 100 percent mortality rate. It does not pose a risk to humans.

The FWP has documented more than 2,000 dead mountain whitefish on some affected stretches of the river. The department projects the total impact to be in the tens of thousands. It also has recently received reports of the kill beginning to affect some rainbow and Yellowstone cutthroat trout.

At this time, the National Park Service is not considering expanding the river closure inside Yellowstone National Park.

Crews are actively assessing the Yellowstone River and its tributaries inside the park’s northern boundary and have not discovered any dead fish.
Yellowstone National Park asks for cooperation from anglers to prevent spread of the parasite into the park. All waters within Yellowstone National Park remain open to fishing.
Invasive, nonnative species are the biggest threat to Yellowstone’s native fish communities.

The park insists all visiting anglers and boaters completely clean and disinfect their gear -- waders, boots, float tubes, boats -- before traveling to the park to help prevent the introduction of this parasite and other aquatic invasive species.

Likewise, they must remove all mud, sediment, vegetation and other debris from waders and boots before leaving a site and traveling to additional fishing locations within the park.

All watercraft entering the park must be inspected by National Park Service staff prior to being launched. Fishing bait is not allowed in the park. It is illegal to transport live fish or move fish or other animals among park waters.

In another fish-related development, park staff will complete the Soda Butte project to remove nonnative brook trout from 28 miles of streams northeast of and within the park to enhance the viability of native Yellowstone cutthroat trout.

This project is about 43 river miles from the Yellowstone River closure area and will not affect or be affected by the closure.

State and federal agencies want to ensure a long-term, self-sustaining population while maintaining genetic diversity and integrity and protecting the ecological, recreational and economic values associated with Yellowstone cutthroat trout.