Hundreds of fish in Shawano Lake suddenly died in late May. This happened shortly after the largest chemical treatment in the state was used on the lake, which has left some thinking that the treatment killed the fish. But was that the case? The DNR weighs in on the issue and explains a thing or two that may surprise you.
The Wisconsin DNR says there has never been a documented fish kill after an aquatic herbicide treatment. Today they believe the recent fish kill at Shawano Lake, is something most from the area, are used to seeing.
Eurasian milfoil which is an invasive species in Shawano Lake, is a known problem on for folks in the Town of Cecil.
"Few of my friends said it was terrible weedy the last few years and something had to be done," says Tom Sekora who is taking in some fishing on the lake today.
The DNR agreed with Tom’s friends and spent two days dropping herbicides into the lake in May. It was a project that the DNR had been discussing for nearly 3 ½ years and ended up costing about $200,000 to conduct. But after it was all said and done, some started noticing dead fish, and talking about how the two things could likely be connected.
"Someone was complaining about something happening to the lake with pesticides and a lot of fish dying," adds Bob Bell of Freedom who read some reviews of Shawano Lake before taking his grandson out for a day of fishing.
According to the DNR an estimated 341 fish died just 10 days after treatment of the lake. But they say they have no reason to think it was from the chemicals.
"The concentration that was used on Shawano Lake is 300 times lower than the concentration that's known to kill even a minnow," says Brenda Nordin a Lake Biologist with the DNR.
And in the last nine years, four separate natural fish kills that the DNR is aware of, were more significant than what just occurred in May. Some of those kills amounting to as much as 1,000 fish taken out at a time.
"They all occurred between May 27th and June 6th. It's kind of interesting that this is the exact time frame that this (most recent) fish kill occurred," adds Al Niebur a Senior Fisheries Biologist with the DNR.
Today the DNR attributes the dead fish to a seasonal fish infection that they’re used to seeing this time of year. The DNR standing by their claim that the water is still safe and the fish are ok to eat.
The DNR will continue to monitor the water at Shawano Lake for chemicals and oxygen levels for about the next month to determine whether or not their chemical treatment contributed to the fish kill in any way. But as of right now they report that oxygen levels are more than adequate and they don’t believe that the chemicals used contributed to any fish dying.
