- A large number of fish will likely die this spring in a central Wisconsin reservoir.
State biologists expect a spring fish kill on the Big Eau Pleine reservoir even bigger than 2009.
That's when tens of thousands of fish were wiped out of the waterway.
Wisconsin Department of Natural Resources experts suspect the fish kill has already started.
That's based on reports from area ice anglers.
The DNR says oxygen levels in the Eau Pleine are so low fish can't breathe.
As nutrient-rich sediment and organic material decays, oxygen gets pulled out of the water.
Thick ice and snow keeps light from reaching plants to make more oxygen.
It also blocks contact between the air and the water.
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