KELLY MCEVERS, HOST:
A nearly 200-mile stretch of the Yellowstone River is closed in Montana just as end-of-summer tourism is surging there. The closure is because of a massive fish die-off that wildlife managers are only now beginning to understand. Montana Public Radio's Eric Whitney reports.
ERIC WHITNEY, BYLINE: The 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.
PATRICK BYORTH: It's hard to watch fish die on a river that you really care about.
WHITNEY: 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.
BYORTH: When the river's unhealthy, the economy's unhealthy, so people are hurting on a lot of levels.
WHITNEY: People here are anxious. About 400 came to the first public meeting state wildlife officials have held since closing the river last week. Montana Fish, Wildlife and Parks spokeswoman Andrea Jones told them it's a serious challenge for her agency.
ANDREA JONES: The magnitude of this kill is unlike anything our fish health specialists have seen before in Montana.
WHITNEY: Those 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.
People at the meeting were generally supportive of state wildlife officials' decision to close the river, but some, including Montana wildlife commissioner and fishing guide Dan Vermillion, think it's about time they got some help.
DAN VERMILLION: You know, it's interesting that when you have, like, an oil spill, there's a much more robust multi-agency response, and the federal government gets involved right away.
WHITNEY: 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. For NPR News, I'm Eric Whitney in Livingston, Mont.