Zebra mussels have been found in Lake Hiawatha in Minneapolis, confirming what had been expected for three years.

Minneapolis Park and Recreation Board water quality workers found several of the small, invasive mollusks Aug. 28 on a plate submerged in the lake as a detection device.

The lake had actually been declared infestedin 2010 by the Minnesota DNR, after zebra mussels were found in Lake Minnetonka and Minnehaha Creek, which flows out of Lake Minnetonka and through several other metro lakes, including Hiawatha. The Mississippi River, into which the creek empties, is also infested.

“We knew they were coming,” said Deb Pilger, director of environmental, equipment and volunteer services for the Park Board.



The Park Poard increased inspections of motorboats on city lakes and restricted hours at boat ramps to try to reduce the possiblity that boaters might carry zebra mussels into city lakes. Motorboats can’t access Lake Hiawatha. Pilger said parks workers have also been limiting the transport of equipment from lake to lake.

Pilger said the finding in Lake Hiawatha heightens the risk of infestation in the Chain of Lakes, “which I think is why it makes our programs trying to (limit the spread of zebra mussels) that much more important.”

No zebra mussels have been found in any of the Minneapolis Chain of Lakes, including Nokomis, which is only yards from the creek and is a close neighbor of Lake Hiawatha. Nokomis and Cedar Lake in Minneapolis, like Nokomis and Hiawatha, have detection devices.

Zebra mussels proliferate quickly, affect water quality and can cause myriad problems. Their sharp shells can cut bathers’ feet, and they can form damaging masses on buoys, dock supports, boat parts and other underwater structures, including water intakes.

However, Pilger noted that zebra mussels aren’t expected to thrive in Lake Hiawatha, based on that lake’s nutrients and plant life. Only one of its 53 acres is considered suitable for high growth rates, she said.

“I think we’ll find more next year,” she said. “But I don’t think 2014 will be a year when people say, ‘I don’t want ot be on that beach.’ That’ll take some time.”