MADISON, Wis. (AP) - The state Department of Natural Resources says people might notice more dead fish washing ashore in northern Wisconsin this spring.
DNR biologists expect see die-offs every spring. Ice and snow blocks sunlight from reaching oxygen-producing aquatic plants. As the plants they stop producing oxygen fish need. The DNR documented 18 fish kills caused by low oxygen levels last winter.
It’s rare for lakes to see a total winterkill. Fish often seek out tributaries or springs where oxygen levels are higher. But the DNR says 3 feet of ice still cover many northern lakes and fresh snow that fell last week is making things even darker underwater. That could lead to larger die-offs.
DNR officials are asking anyone who happens upon a winterkill to contact the agency.
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