Montana Officials Discover Dead Fish In Yellowstone River

Aug 25, 2017

Montana officials say they recently discovered dead fish in the Yellowstone River and are waiting on test results to know if they were killed by the same parasite that killed thousands of fish last year.

At the Highway 89 fishing access south of Livingston Friday morning, wildlife biologists coax a green raft into the river. This is a beautiful morning for a float. Everything is basked in a golden, late-summer hue and the river looks cool and clear.

“It’s like yeah, it’s great to be out but I wish I was out here for a different reason,” says Scott Opitz, a fisheries biologist with Montana Fish, Wildlife and Parks.

He and his team have been floating this stretch of the Yellowstone all week collecting dying fish.

“They’ll kinda be trying to swim, but maybe not upright, on their side. Sometime just kind of floating or drifting and twitching occasionally,” Opitz says.

So far they’ve found almost 100. Most are mountain whitefish, with a couple of dead suckers and one dead brown trout.

Opitz says they don’t yet know what’s causing the fish to die -- test results are expected next week -- but last year, thousands of fish were killed in the Yellowstone River by a parasite carrying proliferative kidney disease, or PKD.

The outbreak forced officials to close a 200-mile stretch of  river just as end-of-summer tourism was surging.

But this year, they haven’t found nearly as many dead fish.

“Our hope is that this kill is going to be of much smaller magnitude than what we saw last time,” he says.

Opitz says the water is higher and cooler than it was last year, and that could slow the spread of the parasite, which thrives in warmer waters. And Travis Horton, the regional fisheries manager for FWP, says the agency is better prepared to handle a potential parasite outbreak.

“Now that we know more, we’re not going to be doing extreme closures of large chunks of river," Horton says. "If they’re needed they are going to be on small scales and would be expanded out as needed. But I think a lot of folks that the river is just going to get closed down, but at this point the agency hasn’t discussed it.”  

Opitz says his team will continue floating the river and counting dead fish until the fall, when cooler temperatures should slow or stop the die-off.