Huge numbers of fish are killed when sucked into the screens of powerful water intake systems, the Chicago Tribune reported Thursday.
In addition, billions of eggs, larvae and juvenile fish small enough to pass through the screens are killed by the intense heat and high pressure inside the coal, gas and nuclear plants, the newspaper said.
When the water is pumped back into the lakes it is 30 degrees hotter, which results in the growth of oxygen-depleting algae that can kill even more fish.
Dubbed "once-through" cooling, the process is banned at new power plants, but the issue has been largely ignored at older plants by federal and state environmental regulators, critics say.
"These plants are consistent killers, plain and simple," Frank Reynolds, a commercial fisherman on Lake Erie, says. "They're trying every way they can to avoid doing something to protect the fish."
Power company representatives respond that the expense of phasing out once-through cooling at older plants would force dozens of plants to close with the loss of thousands of jobs.