Zebra mussel introduction prevented by county inspector

A vigilant Washington County watercraft inspector prevented the introduction of zebra mussels to Big Marine Lake in Washington County, which is currently not known to be infested with the harmful invasive species.

“If not for the vigilance of this DNR-trained county watercraft inspector, zebra mussels would have been introduced to Big Marine Lake,” said Adam Doll, DNR watercraft inspection program coordinator.

Nearly 1,000 watercraft inspectors were hired this year and trained by the Minnesota Department of Natural Resources. County watercraft inspectors are funded by a portion of the $10 million Minnesota counties receive to prevent the spread of aquatic invasive species.

“This incident is an example of the great collaboration between the counties and the DNR inspector training program,” Doll said. “It also reminds everyone to inspect watercraft when they leave infested waters or face a fine and the possibility of infesting a Minnesota lake.”

The Washington County inspector said the sides and bottom of a boat entering a Big Marine access appeared to be clean. Upon checking more closely, she spotted live zebra mussels on vegetation that had not been cleaned from the boat’s anchor. The boat’s operators said the boat had been on White Bear Lake earlier that day, where zebra mussels were confirmed in 2014.

The investigation into the incident is ongoing. First-time offenders trying to bring a watercraft with invasive species onto a lake that is not known to have that invasive species face up to a $500 fine.

The DNR trained more than 900 county watercraft inspectors in 2019, to supplement the 100 DNR inspectors and many DNR Enforcement Officers statewide.

Whether or not a lake is known to have any invasive species, Minnesota law requires boaters and anglers to:

Clean watercraft and trailers of aquatic plants and prohibited invasive species.
Drain all water by removing drain plugs and keeping them out during transport.
Dispose of unwanted bait in the trash.
Some invasive species are small and difficult to see at the access. To remove or kill them, take one or more of the following precautions before moving to another waterbody:

Spray with high-pressure water.
Rinse with very hot water (120 degrees for at least two minutes or 140 degrees for at least 10 seconds).
Dry for at least five days.
More information is available at mndnr.gov/ais