Thousands of fish have died in the Midwest because of the blistering, hot, dry summer.
The heat has dried up rivers and causes water temperatures to rise up to nearly 100 degrees in some areas.
About 40,000 shovelnose sturgeon are dead in Iowa last as water temperatures reached 97 degrees.
In Nebraska fishery officials said they've seen thousands of dead sturgeon, catfish, carp, and other species in the Lower Platte River, including the endangered pallid sturgeon.
In Illinois, the hot weather has killed tens of thousands of large- and smallmouth bass and channel catfish.
In fact, so many fish died in one Illinois lake that the dead fish clogged an intake screen near a power plant, lowering water levels.
A spokesman for Edison International, which runs the coal-fired plant, said workers shut down one of its two generators for several hours two weeks ago because of extreme heat and low water levels at the lake, which is used for cooling.
"It's something I've never seen in my career, and I've been here for more than 17 years," said Mark Flammang, a fisheries biologist with the Iowa Department of Natural Resources. "I think what we're mainly dealing with here are the extremely low flows and this unparalleled heat."
The federal U.S. Drought Monitor shows nearly two-thirds of the lower 48 states are experiencing some form of drought, and the Department of Agriculture has declared more than half of the nation's counties - nearly 1,600 in 32 states - as natural disaster areas. More than 3,000 heat records were broken over the last month.
In Nebraska, a stretch of the Platte River from Kearney in the central part of the state to Columbus in the east has gone dry and killed a "significant number" of sturgeon, catfish and minnows, said fisheries program manager Daryl Bauer. Bauer said the warm, shallow water has also killed an unknown number of endangered pallid sturgeon.
"It's a lot of miles of river, and a lot of fish," Bauer said. "Most of those fish are barely identifiable. In this heat, they decay really fast."
