Montana officials are investigating whether an outbreak of disease is responsible for recent mountain whitefish deaths in the Yellowstone River between Livingston and Big Timber.
Montana Fish, Wildlife and Parks began receiving reports of dead whitefish along sections of the river near Big Timber and Livingston last week, according to a news release sent Tuesday.
During checks of the area, biologists saw approximately 200 dead whitefish.
Officials said the deaths could be linked to proliferative kidney disease (PKD), a condition deadly to salmonids like whitefish and trout. The last significant outbreak of the disease in the Yellowstone occurred in 2016, when thousands of whitefish died.
FWP and other agencies are testing samples to determine whether PKD is linked to the kills, the release said. Officials anticipated no closures or restrictions would be applied to the Yellowstone or its tributaries.
Biologists Wednesday found seven dead whitefish over a nine-mile stretch of river between the Springdale Bridge Fishing Access Site and the Grey Bear Fishing Access Site upstream from Big Timber.
Approximately 150 more dead whitefish were confirmed Thursday on a nine-mile section of river between the Pig Farm Fishing Access Site and the Springdale Bridge Fishing Access Site downstream from Livingston.
On Friday, biologists discovered 40 more dead whitefish on a 20-mile stretch of the Yellowstone between the Pine Creek Fishing Access Site and the Highway 89 Bridge Fishing Access Site.
No trout deaths were observed.
FWP recommended that anglers release fish quickly, use lures with barbless or single hooks, handle fish with wet hands and maximize the time fish are in the water to reduce stress on fish.