Yellowstone River Closure From Parasite

Yellowstone River

According to Explore Big Sky, the Montana Fish Wildlife and Parks (FWP) closed the Yellowstone River and its tributaries on Aug. 19, 2016. The was caused by the deaths of thousands of mountain whitefish from parasites. Reports also stated that the infestation was beginning to affect the trout population, however, it does not pose a threat to humans.

Everything north of the Yellowstone National Park boundary, at the Gardiner entrance to Highway 212 bridge in Laurel, is closed. The closing includes all water-based recreational activities like floating, tubing, wading, and most of all, fishing. A total of 183 river miles is currently shut down until environmental conditions improve and the fish stop dying.

However, on August 19, the National Park Service stated they would not be extending the closure to Yellowstone National Park, just yet. Noting that the park’s personnel has not seen any dead fish, that have perished from the parasite, known as Tetracapsula bryosalmonae. Fish that have been affected by the parasite died from a proliferative kidney disease, caused by the parasite.

According to Dr. Eileen Ryce, the parasite has been documented at other sites. The infestation has an astonishing mortality rate of 90 percent of fish infected. This particular parasite attacks salmonids, which  includes salmon, trout, grayling, char, and mountain whitefish.

How They Spread Quickly

FWP representatives report that high temperatures and low water flows, increase stress on the fish. Meaning, that when the water temperature rises the parasite can spread faster. This increases the death rate of the fish, according to a study in the journal, Aquaculture. They also state that closing Yellowstone River is meant to mitigate stressors for the fish. Therefore, decreasing the spread of the parasite to other waters.

It is unclear exactly how the parasite was introduced to the river. However, Dave Moser, a biologist with FWP fisheries, says that the microscopic organism was from other waters, most likely, carried in from unclean boats that were not drained and dried properly, possibly even from waders.

Moser also reported that the rough calculations of the deaths of whitefish are 200,000. Andrea Jones, FWP’s education manager for Region 3, said that the magnitude of the dead fish is unprecedented. She went on to say, mortality rates have not been this high in Montana.

Recent parasite outbreaks have occurred in Oregon, Washington, and Idaho. Ryce claims that the fish are inexperienced when it comes to this particular infection. Meaning, this would be the first open exposure to the parasite for the fish. Montana, documented two other outbreaks, which were in isolated parts of the state, over the past 20 years.

What Is the Impact On the Yellowstone River?

The decision to close the river to any activity by the FWP is solely based on stopping the mortality rate of the whitefish. However, they are also trying to skirt the deaths of other fish, such as rainbow trout and Yellowstone cutthroat fish.

FWP has posted closure notices at all the fishing access sites for Yellowstone River. They are also imploring the public to help limit the spread of the parasite. Representatives say the public can help by cleaning all equipment before moving to other bodies of water.

That said, the economic impact on tourism-related businesses could be exponential, according to Sam Sheppard, supervisor of FWP Region 3. Sheppard stated that this would affect many people and be difficult for the economy.

Travis Horton, FWP fishery manager of Region 3, reports they have not seen a river closing this large, in Montana. He also said, to his knowledge, they have not had to prohibit all water-based recreational activities at Yellowstone River.

Sheppard is calling it a crisis, putting it in simple terms, he says that a dog owner can not even throw a stick into Yellowstone River; the situation is that serious. FWP representatives express that the closure will stay in place until temperatures stop rising, water flow improves, and the fish mortality stops.

By Tracy Blake
Edited by Jeanette Smith


Bozeman Daily Chronicle:  FWP: Yellowstone River fish kill likely more than 10,000
Fox News U.S.: Popular Yellowstone River closes after thousands of fish die

Image Courtesy of Bureau of Land Management Oregon and Washington’s Flickr Page – Creative Commons License

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