First ever cases of 'destructive' algae reported in two Minnesota lakes


A new invasive aquatic species has found its way into two lakes in Minnesota – the first confirmed cases of it in the state's history.

"Starry stonewort," has been found in Lake Koronis and Mud Lake, in Stearns and Meeker counties, the Department of Natural Resources announced Friday.

The grass-like algae produces "dense mats" that could interfere with recreational use of the lake, and can "choke out" native plants, alter the habitat for young fish, and impede the movement of aquatic life.

When the first case was reported in Wisconsin last year, it was described by a local lake association president as "the start of the death of a lake," according to FOX 6, which labeled it "destructive."

It has spread to cover a 53 acre shallow area of the southwest side of Lake Koronis near Highway 55 and from there spread into the main basin and into neighboring Mud Lake.

According to the Star Tribune, property owners along Lake Koronis had been noticing excessive weed growth in recent years, and got to the point where the smell of rotting plants got so bad that they contacted the DNR.

The newspaper adds that there are fears that its presence could attract other invasive species, with a member of the Koronis Lake Association saying it's attractive to zebra mussels.

Lake users brought the algae

The DNR says it is likely to have been spread to the Minnesota lakes by lake users who transported it from an infested body of water elsewhere.

It was first discovered in the U.S. in the St. Lawrence River in 1978 and spread across the northeast. It has been in Michigan lakes for more than a decade, as well as Wisconsin since last year.

The DNR said that such is its spread, its rapid response treatments such as hand removal and applying herbicide would probably not be enough to eliminate the algae for the lakes.

According to the University of Wisconsin, there is no effective biological control agent for the species known at this time.

Officials are now monitoring other nearby lakes to see whether it has spread, and are reminding boaters and anglers to clean aquatic plants and animals from their boats, drain all water by removing drain plugs, and disposing of unwanted bait in the trash.

"It doesn't take that long to drain a live well, pull plugs and check for weeds," Karen Langmo, of the Koronis Lake Association told the Star Tribune. "It’s hard to understand why people don’t want to do it."

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