CODY, WYO. — Park officials have no plans so far to close waters in Yellowstone National Park to anglers and others following a move Friday by Montana wildlife officials to close a vast stretch of the Yellowstone River.

Montana Fish, Wildlife and Parks announced the indefinitely and immediate closure of more than 150 miles of the Yellowstone River and its tributaries to fishing, boating and all other recreational activities.

The drastic move comes after the discovery this week of thousands of fish killed by a rare but virulent parasite. The closure is meant to prevent the spread of the disease to other waters in a state where fly fishing is a cherished pastime for residents and a key draw for visiting anglers who spend millions in pursuit of elusive trout in pristine waters.

The section of the Yellowstone River closed by the order begins at the northern boundary of Yellowstone National Park, in Gardiner, and continues east and south nearly to Billings, the state’s largest city.

Yellowstone spokeswoman Charissa Reid said park biologists are monitoring waters inside the park, which are upstream from the affected areas. Anglers in Yellowstone are being asked to wash and disinfect their waders, rods and other gear to prevent the spread of the parasite.

FWP Director Jeff Hagener said the closure “will have a significant impact on many people,” but is necessary “to protect this public resource for present and future generations.”

The agency has found more than 2,000 dead mountain whitefish along stretches of the Yellowstone River, with an estimated 20,000 or more whitefish presumed killed in the massive outbreak. Some rainbow trout and Yellowstone cutthroat trout have also been affected.

A microscopic parasite is infecting fish with proliferative kidney disease, a rare but serious condition that has only been found in two isolated spots in Montana over the past two decades. It poses no risk to humans, officials said.

Low stream flows and higher water temperatures this summer have exacerbated the effects of the disease on fish populations in the Yellowstone.

It comes just as Gardiner prepares to host a celebration next week marking the Centennial of the National Park Service.

Wildlife officials have said the closure will remain in effect until conditions change, which could take weeks or even months, depending on weather, stream flows and other factors.

Walter Wiese, head fishing guide at Park’s Fly Shop in Gardiner, said an extended river closure would be tough for regional fishing businesses, as well as others along the river, such as whitewater rafting guides.

“If it’s a threat to the Yellowstone River trout population, we support it, but I hope it doesn’t last too long,” Wiese said.

Gov. Steve Bullock said in a statement that the fish kill is “a threat to Montana’s entire outdoor economy and the tens of thousands of jobs it sustains.”

Outdoor recreation supports more than 64,000 Montana jobs and brings in almost $6 billion annually, Bullock said.

“We must be guided by science. Our state cannot afford this infectious disease to spread to other streams and rivers, and it’s my responsibility to do everything we can to stop this threat in its tracks and protect Montana jobs and livelihoods,” he said.

Contact Ruffin Prevost at 307-213-9818 or [email protected].

Ruffin Prevost is founding editor of Yellowstone Gate, an independent, online news service about Yellowstone and Grand Teton parks and their gateway communities. He lives in Cody, Wyo., where he also works...