A number of spotted fish kill in Minnesota lakes have already been reported to the Minnesota DNR.
"Fish kill usually is anything that happens out on the lake or a stream that causes fish to die off. Sometimes it can be natural. Sometimes it can be caused by other things like chemicals or some type of spill." Waterville Area Fisheries Supervisor Craig Soupir said.
Soupir says fish kill during this time of year is natural, and is also referred to as winterkill.
"Generally when the oxygen level gets low during the winter under the ice and it gets to the point where fish can't live anymore," Soupir said.
Soupir says this process affects fish species differently.
"Largemouth bass are one of the least tolerant, so, they'll die off. Walleyes, common carp, they're a little bit lower than that so they'll die off next. Then you'll see fish species that are really tolerant like northern pike and yellow perch which are kind of native to this whole area," Soupir said. 
Black bullheads are the most tolerant, living through almost all winterkills.

With the fish hatchery in Waterville, Soupir says population isn't a concern.
"All the lakes that are stocked in this area are most of the fish come out of the Waterville fish hatchery. Including most of the lakes stocked with walleye. So, that's a pretty big part of what we do," Soupir said.
Soupir says 37 lakes experienced winterkill in 2014, and expects only six this spring. 
Anyone who sees numerous dead fish after the ice melts are advised to report to the Minnesota Pollution Control Agency.


--KEYC News 12