Starry stonewort found in third Stearns County lake

The hunt for Minnesota’s newest aquatic invasive species in nearly 200 lakes across 20 counties has turned up the discovery of starry stonewort in a Stearns County lake.

The state Department of Natural Resources announced Tuesday the finding in Grand Lake — the first confirmation of the invasive algae in a Minnesota lake in 2017. It follows two other infestations of Stearns County lakes by the invasive, which grows into dense mats that can shroud shallow waters, choke out native plants, and create a wall between fish and their spawning grounds.

“My heart sank,” said Scott Palmer, chairman of the Grand Lake Improvement District board, adding about the popular fishing lake: “It’s one of the gems of central Minnesota.”

In 2015, Lake Koronis near Paynesville was the first Minnesota lake confirmed to be infested with starry stonewort, followed by eight other lakes, including nearby Rice Lake in 2016.

Volunteers discovered the invasive at Grand Lake’s public access this month, as part of a statewide event dubbed “Starry Trek,” which drew 200 volunteers to search for starry stonewort when the star-shaped bulbils on its root system are most abundant.

Until now, the 655-acre lake had been infested only by curly-leaf pondweed. Because of the recent finding, the lake group may expand boat inspection hours and it has added a video camera taping boats entering the water and reminding boaters to clean and drain boats.

The DNR also plans to contract with divers to suction the invasive out of the lake before chemically treating it. No lake in the U.S. has successfully eradicated the algae, but Palmer is hopeful that Grand Lake could be the first to do so since the infestation is confined to a small, 8-foot area.

“We have to be realistic we may not be able to, but we’re going to try our darndest,” he said.