ST PAUL, Minn. — Editor's note: The video above first aired on July 22, 2021.
As the weather warms up the Minnesota Department of Natural Resources (DNR) is asking people across the state to keep an eye on your local lakes and rivers.
They want reports on any fish die-offs, which happen occasionally in the spring for a variety of reasons.
“People can help by reporting fish die-offs right away,” DNR limnology consultant Tom Burri said in a news release. “These reports help us determine whether an investigation is needed.”
In the spring when the ice melts off lakes and rivers dead fish are revealed, which is commonly referred to as winterkill. During the winter, snow and ice prevent or limit sunlight from reaching aquatic plants and in turn, reduce the amount of oxygen they produce. If the plants die from lack of sunlight the vegetation will decompose which uses even more oxygen from the water. That lack of oxygen can kill fish.
In mid-spring and summer, fish die-offs can be the result of warming water and infections that spread in fish populations that are already stressed after spawning season. "Species commonly observed in these die-offs include sunfish, crappies and bullheads, and, occasionally, largemouth bass and northern pike," according the news release.
If you see a fish die-off, please call the Minnesota Duty Officer at 651‐649‐5451 or 800‐422‐0798 (the officer line is available 24 hours per day, seven days a week). The DNR encourages the public to know what sizes and types of fish are involved in the fish kill.
For more information about fish kills go to the DNR website.