DNR says fish kills likely to occur as seasons change

The Michigan Department of Natural Resources says residents will likely see dead fish floating on bodies of water over the next few weeks.

Fish kills are localized die-offs of fish populations and other aquatic animals that typically occur in shallow lakes, ponds and canals.

The department says fish often die in February but aren’t noticed until waters thaw in early spring.

Gary Whelan, the DNR Fisheries Division program manager, says a lack of oxygen is the main reason for winter die-offs.

“What happens is that the snow cover and ice cover essentially cut off sunlight into the vegetation. The vegetation dies and uses up oxygen and ultimately causes fish to die and amphibians for that matter too — could be both.”

While the sight of dead fish can concerning, Whelan says the animals are recycled back into the ecosystem.

“Those fish will ultimately become part of the system that dies, and there are lots of decomposers that will use those fish for food supplies. It’s like bald eagles will be glad to pick up a freebie meal, so they get reused in the system.”

Whelan says winter fish kills rarely have a dramatic impact on overall populations and fishing quality.

He says residents can report die-offs on the department’s website at Michigan.gov/EyesInTheField.