Yellowstone River whitefish kill

Two dead whitefish are shown in the Yellowstone River on Saturday. More than 1,000 have been found dead in the river. The cause is unknown.

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After confirming that more than 1,000 whitefish are dead in the Yellowstone River, state officials are assuming the total death toll is much higher.

“It would be fair to say we’re over 10,000,” said Andrea Jones, a spokeswoman for Montana Fish, Wildlife and Parks.

Since late last week, FWP has been looking into the fish kill on the Yellowstone River. It was reported to the department on Thursday by outfitters and guides in the area, and FWP had staff float three separate sections of the river to confirm and determine the scope of the kill.

They were able to confirm the deaths of more than 1,000 whitefish and a few suckers. But because some of the fish have probably sunk to the bottom or have been eaten by scavengers, Jones said it was safe to assume there are many, many more.

“We’re probably only seeing 10 percent of the impact,” she said.

Word on the cause hasn’t come yet. Samples from the fish have been taken to the U.S. Fish and Wildlife Service fish disease and health lab, but Jones said results shouldn’t be expected until after Thursday.

Only whitefish and suckers have been confirmed dead. Jones said the agency received one report of a handful of dead rainbow trout, too, but the agency hadn’t confirmed it.

FWP staff planned to electrofish the river from Loch Leven to Pine Creek on Tuesday. Jones said they planned to catch live fish, both whitefish and trout, and bring them to the lab to gather baseline samples.

The Montana Department of Water Quality sent two water quality specialists to the stream on Tuesday to gather water samples. DEQ public policy director Kristi Ponozzo said they will test for things that might cause human or aquatic health concerns, such as metals, nutrients, acidity and temperature.

“We’re just trying to see if there’s anything in the water that could cause the fish kill,” Ponozzo said.

Ponozzo said the samples would be taken to a Helena lab operated by the Montana Department of Public Health and Human Services. Results won’t be available for at least two or three weeks, she said.

The fish have been seen dead all over the river. Jones said they have reports of belly-up whitefish as far upstream as Cinnabar, near Corwin Springs. Officials have confirmed deaths as far downstream as Springdale.

FWP staff floated from Loch Leven to Pine Creek Fishing Access site on Friday, finding 382 dead whitefish on just the eastern bank of the river. On Saturday, they floated from Pine Creek to Carter’s Bridge and found 383 on the west bank and 354 on the east bank. On Monday, they floated from near the Highway 89 Bridge to Springdale and found another 318 fish.

David Brooks, the associate conservation director for Montana Trout Unlimited, said 10,000 “sounds like a lot of fish to me.”

He said the species is very sensitive to poor river conditions and may be more affected by disease pathogens when a stream is low or hot.

He said the cause appears to not be any sort of pollution, since that would affect all of the fish. He added that if it turns out to be a disease or poor river conditions, ensuring it doesn’t happen again would still have to deal with streamflows.

“The long-term solution is keeping more water in rivers and cleaner water in rivers,” Brooks said.

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Michael Wright can be reached at or at 582-2638. Follow him on Twitter @mj_wright1.

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