I emailed the DNR and here is what i got back

"Thank you for the report. We are aware of the event that is ongoing.
At this time we do not know the exact cause, but are working to get some
answers. As we determine what the cause is we will issue a press
release. You can check our web site for the latest press releases.

Again, thanks for your vigilance and reporting the information to us."

Michael Wilkerson
Fisheries Biologist
ODNR-Division of Wildlife
419.429.8375