Small-scale fish kill on Madison lakes likely related to rapid rise in water temperatures

MADISON – Anglers and boaters venturing out on the Madison chain of lakes in coming weeks may see dead fish collecting in lagoons, channels and bays due to a late April fish kill likely caused by the rapid warmup in water temperatures stressing fish and making them more susceptible to bacterial diseases.

“We are aware of the die off event and have collected fish for testing to confirm our suspicions,” says Dave Rowe, Department of Natural Resources fisheries supervisor in Fitchburg.

Small fish kills due to bacterial infections are common in Madison lakes in the spring but usually occur later. The sudden rise in water temperatures from the 40s to the 60s in shallow habitats like channels and lagoons during late April likely stressed the fish and made them more susceptible at this time to bacterial diseases.

Rowe says the fish die offs appear to be small scale and involve primarily bluegill but also white bass, crappie and largemouth bass. “We have had several fish kill complaints to the hotline in the last week including Waubesa, Winnequah lagoon, and Kegonsa at Fish Camp and Monona,” Rowe says.

He has investigated several sites this week and there were no freshly dead or dying fish but rather the dead fish were being blown into areas where more people were seeing them.

Rowe says that people who see the dead fish do not need to report them to DNR but should not eat the dead fish and should not handle the dead fish without gloves on. Waterfront property owners where the fish wash ashore are encouraged to compost or bury the dead fish.

“Poor water quality and fish being attracted to the warmer temperatures in these lagoons and channels may also contribute to the susceptibility of the fish. The fact that the wind and river currents have also collected the dead fish in concentrated groups make the kill seem more severe than it is.”



Robert graduated from Brandman University, where he got his bachelor’s degree in Business Administration. Born in Massachusetts, Robert’s family moved to Kentucky in 2005 where he spent his college life and worked as an insurance agent for four years. Now is the founder and team leader of the website.


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