Round Lake aeration request makes for hard decision

LITCHFIELD — The Minnesota Department of Natural Resources in New Ulm is considering its first application for a lake aeration system in more than 20 years.

The application by the Round Lake Improvement Association in Meeker County is anything but a sure bet.

“It’s not crystal clear to any of us,” said Jack Lauer, the New Ulm Regional Fisheries Manager, at the conclusion of a virtual public meeting held on the application on Nov. 17. “It’s kind of a hard decision for all of us.”

The DNR makes a decision on the permit application Dec. 21 and is taking public comments through Dec. 1.

The shallow lake south of Litchfield has been a popular fishing destination in recent years. There were 40 boats bouncing on the waves of the 263-acre lake for the fishing opener this year. “It was crazy, never seen anything like that before,” said John Grabow, representing the lake association. The lake has public access, and “there is a lot of the public using it.”

And, there is a lot of public support for installing an aeration system. The lake association raised $10,000 to purchase an aeration system for the lake. It has a shed to house it and the volunteers lined up to install it. The association will take on all of the costs for its operation, maintenance and insurance.

Although the lake is no more than eight feet deep, it is connected downstream to Lake Ripley in Litchfield and upstream to Hoosier Lake, a small lake that has been used as a walleye rearing pond. Fish migrate among the lakes, and anglers have been enjoying the benefits in Round Lake. Grabow has a phone filled with photographs of anglers holding nice-sized catches of walleye, sunfish, crappies, largemouth bass, and northern pike.

The lake is vulnerable to winterkill. Lake association members know that all of the good fishing could end with one harsh winter. Grabow said that is why they want to install the aeration system. It would protect the game fish. Otherwise, it can take years after a winter kill for a diversity of fish to return to the lake.

“It has been a boom and bust, northern pike fishery,” said Scott Mackenthun, fisheries supervisor with the DNR in Hutchinson . The lake is popular with waterfowl hunters and northern pike anglers and dark house spearers, Mackenthun said during the virtual hearing on the aeration application. The lake is kind of unique for the southern region in that it is primarily managed for its northern pike population, he added.

The occasional winter kills are important for the northern pike fishery, analogous to fire on the prairie, Mackenthun explained. The occasional winter kills knock down the population of bottom feeders such as bullheads and in the resulting vacancy, northern pike expand in numbers and grow rapidly.

“We use winter kill to manage this fishery,” said the fisheries supervisor.

There are currently 110 permits for lake aeration systems in the southern portion of the state overseen by the New Ulm DNR office, according to Lauer, the regional fisheries supervisor. About 50 to 70 are actually operated in any given year, he said.

Overall, the DNR is seeing a trend towards fewer aeration systems in operation. They can be costly and difficult to operate, said Lauer.

Aeration systems don’t always prevent winter kills. Partial winter kills still occur, he said.

They also create a drowning risk by creating areas of thin ice and open water. He pointed to two drownings on Lake Benton.

Aeration systems can be beneficial to game fish in some lakes, according to Mackenthun and Lauer. Lakes that offer an area of 15 feet in depth or more, such as Lake Sleepy Eye, tend to benefit the most, they explained.

Aeration systems prevent winter kills by providing refuge areas where some game fish can survive when oxygen levels are depleted during a hard winter, according to the two.

Mackenthun and his fisheries crew tossed six gill nets into Round Lake in August and confirmed why so many people are fishing the lake. The nets held walleyes and northern pike and other game species. The crew did not sample for fish along the shoreline, but Mackenthun said he has no doubts about the availability of sunfish and largemouth bass along it.

The fisheries supervisor pointed out that when those gill nets were pulled up in August, each net held about 95 to 96 fish. Of the catch in a net, over half or 55 were bullheads, along with 18 northern pike, three walleye, 1.3 yellow perch, one crappie and a “spare” largemouth bass.

Bullheads are very abundant in the lake, and were commercially harvested from it during the 1950’s to 1970. Mackenthun said that an aeration system could inadvertently “tip the scales” in favor of bullheads during a harsh winter by allowing them to survive in large numbers. The lake could become a “bullhead pump,” allowing the bottom feeders to expand and migrate to Ripley and Hoosier lakes.

Grabow said it’s also possible the reverse could happen. By helping game fish in Round Lake survive a harsh winter, they could benefit the connecting lakes.

“We are not asking for anything from the DNR besides the permit to run the aerator,” Grabow told the Tribune “We just want to give it a chance. We are all about helping the lake and creating an awesome fishery.”

If it turns out that the aerator benefits bullheads to the detriment of game fish, “we’d shut the aerator off,” he said.

Comments on the aeration application should be sent via email to the Hutchinson fisheries office: hutchinson.fisheries@state.mn.us .

1/4: A young angler holds a sunfish he caught on Round Lake south of Litchfield. The Round Lake Association is seeking a permit to install an aeration system to protect the diversity of game fish being caught in the lake in recent years. The shallow lake is vulnerable to winter kill, but the occasional winter kills also benefit the lake by reducing the number of bottom fish and allowing its natural population of northern pike to take advantage of the vacancy created. Submitted

2/4: Round Lake is holding a diversity of fish in recent years, as evidenced by this largemouth bass held for a photo with the young angler who caught it. Submitted

3/4: Round Lake in Meeker County is known best for its northern pike, which benefit from a "boom and bust" cycle of winter kills. A young angler holds a northern pike he caught in the lake. Submitted

4/4: Ice fishing houses on Foot Lake. The removal deadline is March 1. Erica Dischino / West Central Tribune file photo