DNR issues ice warning for aerated lakes
Tue, 02/04/2020 - 4:58pm
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The Minnesota Department of Natural Resources urges people to use caution on lakes with winter aeration systems.
Aeration helps to prevent fish winterkill. Low oxygen levels during the winter can cause fish to die. This is known as winterkill. Aeration systems agitate and mix water in the lake. Warmer water near the bottom of the lake rises to the surface and melts an area of the ice. Oxygen from the air can then be incorporated into the water, and light can also penetrate further into the water, helping with photosynthesis and increasing oxygen.
Aeration creates areas of thin ice and open water that are extremely hazardous to people and pets. Open water areas can shift or change shape depending on weather conditions, and leaks may develop in airlines, creating other areas of weak ice or open water.
Area lakes include Pine Lake in Clearwater County; Cable, Cameron, Maple and Sarah Lakes in Polk County and Lake Bronson in Kittson County. The updated list of aerated lakes and more information is available at mndnr.gov/eco/lakeaeration.
“We’re urging people to use caution anytime they venture onto lake ice, especially at night,” DNR aeration coordinator Amanda Yourd said. “Extreme care should be taken on aerated lakes. Watch for the large orange and black warning signs at high use public accesses and the required thin ice signs around open water areas.”
Aeration systems help prevent winterkill of fish populations by adding oxygen to the lake and, in certain situations, help protect shorelines from ice damage. They are generally operated from the time the lakes freeze until the ice breaks up in the spring. About 260 lakes have aeration systems operating on them this winter. Private hatchery operators also use aeration systems, usually on small lakes without public accesses.
A DNR permit is required to install and operate an aeration system. Permit holders must issue public notices, post warning signs and inspect the systems at least once every seven days. Private groups or citizens operating aeration systems generally are required to have liability insurance. DNR staff ensure permittees comply with all requirements and regularly inspect systems for safety.
Some municipalities may have ordinances that prohibit entering into the thin ice marked area and/or prohibit the night use of motorized vehicles on lakes with aeration systems in operation. These local regulations are often posted at accesses where they apply.
Questions concerning aeration or thin ice can be answered by calling a regional or area fisheries office or the DNR at 888-646-6367.