Coming weeks are likely to shed light on winter kill in lakes; DNR officials expect some in west central Minn.
SPICER — We will likely discover winter kill of fish in some of the area’s shallow lakes when the ice melts in the upcoming weeks.
There is really no way to know how much winter kill has occurred until the ice leaves area lakes. Coahran said fisheries workers have been monitoring oxygen levels in shallow lakes where winter kills have historically occurred.
They’ve found low oxygen levels in some, but that does not necessarily mean the fish have died off.
The oxygen levels declined slowly through the winter, which gives fish a better chance of surviving until ice out, the fisheries supervisor explained.
Ice anglers have called with reports of suspected fish kills in Lake Lillian and West Norway. They’ve drilled holes to find dead fish surface in them.
Fisheries workers rely on calls from people to investigate possible fish kills. Usually, the dead fish can be seen as ice melts and pulls away from the shoreline.
The conditions that cause winter kills were certainly experienced this year. Area lakes iced over early. And, snow blanketed the ice through much of the winter, blocking sunlight to aquatic plants. Plants die off and decompose, which takes oxygen out of the water.
Coahran noted that there was minimal water flow in the lakes this winter due to the deep freeze. A late ice out- which also appears likely- is another factor that can contribute to winter kill.
There is still a thick sheet of ice on most area lakes, but whether this year’s ice out will be as late as in 2013 is anybody’s guess. Last year, Green Lake didn’t give up its ice until May 8, the latest date in record books dating back to 1897.
The median ice out date for Green Lake is April 16. Lake Wakanda south of Willmar has a median ice out date of April 11.