NEW ULM — Minnesota Department of Natural Resources fisheries staff presented survey data on Brown County lakes and details on a hatchery project during the New Ulm Area Sport Fishermen’s 40th anniversary reunion Saturday.

Assistant Area Fisheries Supervisor Tanner Stevens and Supervisor Scott Mackenthun reviewed survey results and management plans for lakes the club has supported through aeration, stocking, habitat work and advocacy.

Gill net sampling was used on Hanska Lake to tests the health of the walleye population. Gill nets consist of vertical panels of netting set overnight in fixed locations and depths. Fish swim into the mesh and become caught behind the gill covers. Biologists retrieve the nets the next day, count, measure, and release most fish. The resulting “fish per gill net” figure serves as a consistent index of relative abundance that allows year-to-year and lake-to-lake comparisons.

Walleye numbers are relatively strong at Hanska Lake. Walleye measured 10.8 fish per gill net. Most of the walleye were three years of age and in the 10- to 13-inch range. This level is considered abundant for walleye in these lakes.

However, fish condition averaged in the mid- to upper 80s on the 0-100 scale, which is considers below-average.

A fish condition factor, often measured on a 0-100 scale, assesses a fish’s plumpness or health relative to its length. A higher number indicates a healthier, plumper fish, while a lower number suggests a skinnier or less healthy one.

“We’re going to keep watching the forage base, perch and shiners, to see if that’s why the walleye aren’t as plump as we’d like,” Stevens said.

Catfish numbers at Hanska Lake measured 20 per net, averaging 18-19 inches. Freshwater drum (sheephead) numbers decreased from prior surveys.

For the crappie survey on Clear Lake, DNR biologists used trap nets set under the ice. A “lift” means pulling the net up through a hole in the ice after it has fished for a set period. 

Clear Lake recorded 237 crappie per lift in the ice survey, mostly 3-years-old. Most age-3 crappie measured about 8 inches, with some at 11- to 12 inches.

Past winter-kill events reduced competition and produced this year’s class. Current abundance has slowed growth rates.

Management options include increased angler harvest of smaller crappie and possible regulation changes such as higher daily limits. 

“Crappie is what this place kind of produces,” Stevens said. “We’re looking at ways to make the size structure a little better.”

At Sleepy Eye Lake, sampling efforts are ongoing, as it is one of the key lakes in Brown County still undergoing assessment. The recent sampling activities aim to provide current data on the lake’s condition. Walleye management in the area includes continuous stocking, particularly in “rearing ponds.” These are small, protected bodies of water used to “grow out” fish for stocking purposes to ensure the health and sustainability of the fishery.

Scott Mackenthun reported plans to replace the Waterville fish hatchery with a $14 million facility.

The current hatchery has space constraints and uses pond water that produces temperature swings and disease risks. The new facility will use well water with modern tanks.

Construction begins later this summer. The project will include bio-secure tanks, higher production capacity for walleye fingerlings and muskies, and improved indoor rearing of larger fish.

“This gives us way more flexibility and efficiency,” Mackenthun said. “We’re excited about the fish production potential for south-central Minnesota lakes.”