3:59pm

Thu June 16, 2011
Environmental Watchdog

Algae may be Cause of Ohio River Fish Kill

The head of Louisville's Sewer District says the fish kill on the Ohio River last night may have resulted from an algae bloom, rather than a chemical spill as was previously reported. The sheen on the Ohio River was noticed south of Rubbertown by cameras at Dow Chemical’s plant, and about 20 Asian Carp were found dead. It was initially thought to be a chemical release from somewhere upriver, but water sampling by three separate entities was negative.

Now, MSD Executive Director Bud Schardein says the culprit could actually be an algae bloom, which suffocated the fish.

“We get warm weather temperatures for several days and the algae starts growing from the nutrients in the water,” he said. “And then usually after you have a rain event—and we had about an inch and a half or two inches of rain yesterday—these blooms turn over and any fish that are around them usually suffocate for lack of oxygen in the water.”

But the weather isn’t the only cause– excess pollution and nutrients can also cause a bloom.

“We use a lot of fertilizers,” Schardein said. “I know we talk about the dead zone in the Gulf of Mexico, and that’s just basically the result of nutrients that have washed downstream. And along the way, once they’ve warmed up sufficiently with water temperature, they start creating algae.”

MSD won’t know for sure if algae is to blame until the fish tissue is tested, and results should be ready in a few days.