Yellowstone River Fish Kill

yellowsThe upturned, bloated bodies of mountain whitefish litter the banks of the Yellowstone River at a spot typically thick with anglers and drift boats. The native species is being killed by a parasite that affects their kidneys. So far it hasn’t been found inside Yellowstone National Park itself, and the river’s prized wild trout appear to be fighting it off. But Patrick Byorth with the conservation group Trout Unlimited says the fish killed downstream of the park still hits like a punch in the gut. The magnitude of this kill is unlike anything our fish health specialists have seen before in Montana.

Not only is fishing now forbidden. People aren’t even allowed to float on the river or enter it at all to prevent the parasite from spreading. That means river guides in one of the world’s top fly fishing destinations are canceling reservations, and Byorth says tourists are going elsewhere.

Specialists are scrambling to get a good assessment of how far the parasite has spread, whether it’s affecting the Yellowstone’s hundreds of miles of tributaries and to sequence the genome of the parasite, which will help them understand exactly what they’re up against.

Biologists expect the outbreak will die down when the water temperature in the Yellowstone River drops next month, but they say it may take until next spring when the river level rises with spring runoff before things get closer to being normal again. At this point, they’re not making any firm predictions.