Harsh winter may kill fish in some Illinois lakes

Long periods of snow cover and thick ice may kill off fish in some Illinois lakes and ponds.

The Lake County Health Department is advising residents to report fish kills. Dead fish along shores should be collected and disposed of in the trash.

Mike Adams is a senior biologist for the health department. He says snow and ice block sunlight, reducing the amount of oxygen in the water. That causes fish to die from low oxygen stress. Trout are the most sensitive to the lack of oxygen. Walleye, largemouth bass and bluegill also have some sensitivity to the problem.

Restocking a pond or lake is rarely necessary because enough fish usually survive to repopulate the body of water in a couple of years.