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Winter Fish Kills Possible

Due to the severe weather of the past few months, our fisheries staff is reporting that “winter fish kills” may be possible at some Forest Preserve lakes and ponds. These kills are caused by heavy snow cover over thick ice, blocking sunlight from penetrating the water. The lack of light prevents the aquatic plants in the lake from producing oxygen. Reduced levels of dissolved oxygen in the water could result in the suffocation and death of fish. As the ice melts, the fish become more noticeable at the surface and along shorelines.

“If a fish kill does happen, it’s typically the older or more stressed out fish that don’t survive the severe winter – we don’t expect to lose entire populations of any species in a lake,” said Forest Preserves Fisheries Biologist Steve Silic.

Typically, fish kills are not that bad for a lake, and the fisherman should not worry about the overall health of the fish populations, Silic noted. As the snow and ice melt, fisheries staff will be monitoring waterbodies around the preserves. Stay tuned to this newsletter for more information.

Learn more about fishing on our Fishing Page.