Boat covered in invasive mussel species stopped before entering California lake

A boat blanketed in invasive golden mussels was stopped just in time at a Folsom Lake decontamination site Saturday, preventing the destructive species from entering one of California’s most popular reservoirs.

The vessel arrived at Mello Marine in Folsom for the mandatory decontamination and tagging required before launching into the lake. During the inspection, workers spotted clusters of golden mussels clinging to the underside of the hull.

“You can see them underneath here. But as you closer examine it, there’s mussels all over the bottom of the boat,” Sally Mello, owner of Mello Marine, told KCRA.

Mello said her team has decontaminated roughly 6,000 boats since 2025, but this was the first time they had encountered golden mussels.

According to Mello, the boat, which had come from the Sacramento-San Joaquin Delta, had followed all the required steps, including mandatory watercraft inspections and decontamination protocols, with plans to continue north to Oregon after visiting heavily used Folsom Lake, which draws more than 2 million visitors a year.

“Imagine, again, if this boat went to Oregon and now just gets put in the Oregon waters and now it’s north of where it is now,” Mello said.

Golden mussels — an inedible invasive species known scientifically as Limnoperna fortunei — build up pollutants, toxins and dangerous bacteria in their tissues, and attach to hard surfaces like pipes, umps and other infrastructure, raising concerns about potential damage to water delivery systems, agriculture and the surrounding environment.

Officials stress that once established in a waterway, golden mussels are nearly impossible to eradicate.

“We’re trying to keep it off Folsom Lake. It’s not there yet. If it gets there, it’s going to be a problem,” Mello said.

A golden mussel was found on a boat in Folsom Lake last year, while authorities recently fined a boater $5,000 at Lake Tahoe for tampering with an inspection seal aimed at stopping the spread.

The California Department of Fish and Wildlife has been notified of the boat contamination and is likely to inspect the boat this week. It will be fully decontaminated and quarantined for 30 days before it can return to the waterways.

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