Fish and wildlife managers put ‘more teeth’ into Southwest Lake Heron

For the fifth time in as many decades, Heron Lake in far southwest Minnesota has a revamped natural resource management plan.

New in 2022 for this historic waterfowl pool will have a strong focus on stocking, namely walleye and northern pike. Are duck hunters okay with that?

In short, yes. But it took some explaining to Maggie Gross, the shallow lakes specialist who helped finalize the management plan this month for the Department of Natural Resources.

“We need more teeth in the water,” Gross said.

The systematic addition of predatory fish will bolster the DNR’s attack on the destructive carp, bullheads and fathead minnows that crowd the lake, she said. Since the early 1900s, these rough, fast-growing fish have stirred up the bottom and wiped out natural beds of wild celery and other plant foods. When the food disappeared, the once stormy clouds of migrating ducks and geese made Heron Lake one of the most productive staging areas for waterfowl in North America.

Gross said stocking predatory fish in Lake Heron is not new to MNR, but it hasn’t been done with frequency. She said duck hunters, some of whom belong to century-old private clubs on the north side of the lake, balked at the idea during initial discussions. But Gross said the pushback eased when the DNR provided new wording to emphasize that the agency would stock walleyes and northerns for the benefit of wildlife, not to create a recreational fishery.

“We wanted a more comprehensive plan of how we were going to tackle rough Lake Heron fish,” she said.

Coupled with intentional water withdrawals from the lake, the primary objective is to promote the growth of aquatic vegetation. Maintaining plant life in Lake Heron will not only feed the ducks, but will purify the water. The growth of aquatic vegetation helps reduce agricultural runoff pollution of suspended sediments and excess nutrients.

Gross said the new plan calls for periodic stocking of fish, especially in conjunction with water withdrawals. According to the plan, the levies will kill fish and mimic drought conditions that allow time for plant seeds to germinate. Restocking the lake with walleye and northern walleye would allow them to eat rough fish larvae and babies when water levels return, delaying their reproduction.

“We mainly want to really ramp up those storage efforts if we get to a pullback,” Gross said.

Michael Mooney, president of the Delta Waterfowl Foundation and member of the Heron Lake Farms hunt club, said the new emphasis on stocking fish increases the risk of strengthening the Heron Lake angler group. That’s why it was important for MNR to emphasize the intent of the management plan, he said.

“It’s a good plan and a start, but we need to do more,” Mooney said. “I couldn’t be happier with the start.”

Also new to the management plan are automatic triggers for when MNR should draw from the lake. According to the plan, water clarity will be the most important measure. Even at that, DNR officials anticipate only one intentional harvest every eight to ten years.

Located in agricultural countryside near the bottom of a large watershed laden with agricultural drains, Lake Heron has suffered from runoff pollution. Less than 3% of the land in the watershed is preserved as grassland, according to the DNR.

The management plan applies to North Marsh, North Heron and South Heron — collectively designated by MNR as one wildlife lake. Including Duck Lake, the entire basin is approximately 8,000 acres in size. It has an average water depth of 2.9 feet and a maximum depth closer to 6.5 feet, according to the DNR.

The new management plan doesn’t offer a solution to the drainage problem, but Gross said the agency will work with “local partners” to promote best management practices on the ground to “improve the quality of the water.” ‘water flowing in Lake Heron’.

Albert Henning, a farmer president of the Jackson County Conservation League, said it’s been difficult for landowners in the area to join government-funded land conservation programs because land in the area is highly valued for agricultural production. Good farmland in the watershed sells for $11,000 to $12,000 an acre, sometimes more, he said.

But he is optimistic that more state-funded buffer strips – vegetative borders around waterways – will form in the short term to mitigate runoff. He said it’s “part of the upgrade”. He also warned that there is no going back on the importance of agriculture to society or its dominance in the region.

“It will never come back to farming 20 acres,” Henning said.

Improvements in the new DNR management plan include a major repair of the Lake Heron outlet, the so-called State Dam. The dam’s 40-foot hydraulic gate is currently unusable because the hydraulic cylinders that raise and lower the gate need to be replaced. Gross said the DNR hired an engineering company to explore options for fixing it. The cost of repairs could exceed $200,000, but the structure is essential to accomplish the drawdowns of the lake.

“It’s a high priority for the DNR and we hope to fix the state dam as soon as possible, but we don’t have a specific timeline yet,” she said.

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