About 40,000 shovelnose sturgeon were killed in Iowa last week as water temperatures reached 97 degrees.
Nebraska fishery officials say they've seen thousands of dead catfish, carp, and other species in the Lower Platte River, including the endangered pallid sturgeon.
Officials in Illinois say the drought has claimed tens of thousands of large- and smallmouth bass
and channel catfish and killed many of the endangered greater redhorse fish.
The fish are dying amid one of the hottest and driest summer in decades. More than 3,000 heat records were broken over the last month.