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Spring thaw may bring fish kills to Michigan waterways

Mar 8, 2017

As ice and snow melt, Michiganders should not be surprised to come across fish kills.

The state Department of Natural Resources said winter conditions often cause die-offs of fish and other aquatic creatures like frogs, toads, turtles and crayfish.

According to the DNR, winter kills are the most common form of fish kill. They are most often found in shallow lakes, ponds, streams and canals as winter ends.

"These are fish that die because there are low oxygen levels in the lakes, and that usually happens when there's ice cover and snow cover that prevents the sunlight from getting through," said Martha Wolgamood, DNR Fisheries Division Hatchery Manager. 

Low oxygen levels can also be caused by weed growth and decomposition of dead plants, according to Wolgamood. And fish can become stressed because of low energy reserves in winter, and rapid changes in water temperature.

"These kills are localized, and typically do not affect the overall health of the fish populations or fishing quality," said Wolgamood.