Zebra mussels found in popular Carver County lake

Two zebra mussels attached to a native mussel
Two zebra mussels attached to a native mussel
Courtney Perry for MPR News | 2015 file

Zebra mussels have been discovered at Lake Minnewashta, a popular Carver County lake. Regional conservation officials said Wednesday they're working quickly now to stop a lakewide infestation by the invasive pests.

Minnehaha Creek Watershed District staffers found four zebra mussels last week on rocks in shallow water under one dock at the public boat access. Ten more were found nearby the following day. Their size suggested they were likely not reproducing, the watershed district said in a statement.

Officials said they were working with the Minnesota Department of Natural Resources on a plan to keep the mussels in check.

A barrier will be installed around the public boat access to contain the infestation. Another will go in at the channel that connects the bay where the public boat access is located to the rest of the lake.

The district said its weighing options for treatment, noting the "low number of zebra mussels detected, their young age and their location improve the chances for success."

More than 200 Minnesota lakes and rivers are now confirmed with zebra mussels, an invasive species that can push out native mussels and cause other problems for lakes and boaters. That includes Lake Minnetonka, which sits near Minnewashta.

The invasive mussels have sharp edges that can cut if stepped on. They can also cause more algae and weed growth — they filter the lake water, allowing sunlight to penetrate more deeply. They attach to boats, making it easy for them to travel and contaminate other waters.

DNR officials have long pleaded with the public to protect against zebra mussel contamination by cleaning boats, draining all water and keeping plugs out when transporting boats between lakes and disposing of unwanted bait in the trash.

Last year, an "aggressive treatment" in Christmas Lake, near Lake Minnetonka and Lake Minnewashta, showed some success against zebra mussels. By October, however, the DNR conceded it had lost the fight and that the zebra mussels had continued to reproduce and establish there.

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