Fish biologists with Montana Fish, Wildlife and Parks are trying to determine why fish are dying on a section of the Madison River south of Three Forks.
The dead fish were first reported to FWP earlier Tuesday by anglers floating in Beartrap Canyon.
FWP staff investigated the report by floating and walking a 10 mile stretch of the banks of the Madison from just upstream of the Ennis Dam to the Warm Springs Boat Launch. Through Thursday, the agency reported finding 814 dead whitefish, 11 brown trout, six rainbow trout and three suckers.
FWP says biologists have collected samples from dead and dying fish and submitted them for testing.
FWP staff will continue to monitor conditions on the Madison River. They also urge anglers who see dead or dying fish to call the FWP Bozeman office at (406) 577-7900.
