Smelly first weekend in May for Beaver Lake

Dead sunfish float near the shore on the northwest side of Beaver Lake. Thousands of sunnies died on the lake due to a partially clogged aerator and a late ice-out, DNR staff said. (Patrick Larkin/Review)

County hired commercial fisherman to haul away over 7,000 pounds of dead fish

Something smelled funky at an East Side lake going into the weekend of May 4.

One day it was too much, and Beaver Lake regulars Art and Joan Harder decided to walk elsewhere. The couple lives only a few blocks from the lake and said they walk around it every chance they get when the weather is nice.

“We went to Battle Creek because the smell was so bad,” Art said last week.

Though Joan had never smelled a corpse, she said imagines the smell would have been similar.

The stench came from thousands of dead fish rotting along the lakeside.

Workers reported finding sunfish, largemouth bass, channel catfish and crappies smattering the shoreline, said Dave McCormack, assistant regional fisheries manager at the Minnesota Department of Natural Resources. DNR staff say the kill off was probably due to an underperforming aerator.

Art has been coming to the lake for nearly 40 years and said this was perhaps the largest fish kill he’s ever seen there.

It was so thick with dead fish that Ramsey County Public Works, which maintains aerators in area lakes, hired a commercial fishing crew to lug some of them away. Terry Noonan, environmental supervisor for the public works department, said the crews estimated pulling out 700 to 800 pounds of fish. To his knowledge, the county has never before had to hire fisherman to pull belly-up fish from a lake.

The sunnies got the worst of it -- there were enough dead sunfish that the DNR stocked new ones on May 7 to make up for the large number of that died, McCormack said. “You could actually catch them today if you were in the right spot.”

McCormack said there were no immediate plans to reintroduce other types of fish, although the largemouth bass population suffered a lot as well. “Some might’ve made it through,” he said, and “it’s not the end of the world out there if they don’t get in there right away.” If there are still surviving bass in the water, they will repopulate the lake fairly quickly, he added.

Other fish in the lake like northern pike and crappies did not appear to have had significant death tolls, DNR staff said.

Aerating saves lives

Though fish kills are regular occurrences, especially during long winters, mass die-offs like this one are usually thwarted by aerators in shallow bodies of water such as Beaver Lake. With aerators, “you normally think fish will make it through,” McCormack said.

Noonan said other area lakes, including Island Lake, Lake Como and Otter Lake are similarly shallow, and are also aerated. None of them had fish kills this spring, he said.

The Beaver Lake problem was, it seems the aerator was suffering from mechanical mishaps right when the fish needed it the most, he said. “We had low oxygen into the lake at a critical juncture” late in the winter, he said.

Noonan said county public works staff, who maintain the aerators, were out at the site in late March. They observed at that point that “something doesn’t seem to be working as well as expected,” he said, so they cleaned out a water chute to try and address the problem.

But, the aerator trouble had “really, really bad timing,” McCormack said, which likely caused the die-off.

The unit on Beaver Lake was put there in 1992, Noonan said, and was a “pump and baffle” system. Other lakes in the area have similar systems with similar ages, and have been functioning without incident, he said.

Ramsey County Public Works and the DNR will meet “to see if we can identify improvements to the existing system or we will attempt to install an electrical system,” Noonan said. In addition, the current system is going to be pulled out and inspected over the summer.

He said he’s “not really sure why this system would not be as effective as other systems,” and said that the cause of the die-off had not been determined yet.

In shallow lakes, fish more or less rely on aerators, especially towards the end of a long winter, said McCormack. Aerators create a small oxygenated area in the lake that is a sort of refuge for the fish as oxygen levels get lower and lower over the course of a winter due to ice and snow cover. So, a long winter with a late ice-out, combined with a mechanical difficulty, spelled death for the sunfish and other species.

At any rate, the dead sunfish could be a good thing for the lake. “There were probably too many sunfish,” McCormack said. 

Contact Patrick Larkin at 651-748-7816 or at

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