Throughout the Midwest, record temperatures mean trouble for wildlife as well as discomfort for human beings. Thousands of fish are dying in areas where water temperatures have spiked to nearly 100 degrees. Fishery officials across the country are reporting massive die-offs of species due to complications from extreme weather and low flowing rivers and streams. Last week in Iowa, 40,000 shovelnose sturgeon died after trying to cope with 97 degree water – and that is just one record being broken amongst many in the driest, hottest summer in US history.
This season, the federal US Drought Monitor shows that two-thirds of the lower 48 states are in some form of drought. The Department of Agriculture has already declared that over half of the nation’s counties are national disaster areas. This means 32 states and nearly 16,000 counties are contending with scorching heat. 13,000 records have been broken in the last month alone. Along the Lower Platte River in Nebraska, thousands of dead carp, sturgeon, catfish, and bass have been washing ashore. Biologists in Illinois have been alarmed to see thousands of endangered and threatened species, such as the greater redhorse fish, among the tens of thousands of animals perishing from extreme conditions. In Illinois’ Aux Sable Creek, evaporation has made large swaths of the waterway disappear, killing what biologist believe may be millions of fish across the state.
Mark Flamming, a biologist with the Iowa Department of Natural Resources said, “It’s something I’ve never seen in my career, and I’ve been here for more than 17 years. I think what we’re mainly dealing with here are the extremely low flows and this unparalleled heat.”
In addition to the ecological cost, the loss of so many fish has taken a massive financial toll on local economies. A power plant near Powerton Lake in Illinois was forced to shut down after huge numbers of dead fish clogged an intake screen and lowered water levels and forced the shutdown of a generator. Iowa Department of Natural Rresources officials claimed that the sturgeon that perished in the Des Moines River represented a $10 million loss of revenue from caviar.
While weekend rain in Iowa improved the conditions in some of the streams and lakes, temperatures were still hovering around the 80’s, and sturgeon populations were reported to show additional signs of stress. Said Mark Flammang, “Those fish have been in these rivers for thousands of thousands of years, and they’re accustomed to all sorts of weather conditions. But sometimes, you have conditions occur that are outside their realm of tolerance.”
Heat also causes a host of other complications including an increase in bacterial infection, clustering of animals in areas that make it easier for predators to attack vulnerable animals, and depleting populations to a point where breeding becomes difficult.