California agencies combatting the spread of invasive quagga and zebra mussels are reminding boaters to remain cautious over Labor Day weekend.

Quagga and zebra mussels are invasive freshwater mussels native to Europe and Asia. They multiply quickly, encrust watercraft and infrastructure, alter water quality and the aquatic food web and ultimately impact native and sport fish communities. These mussels spread from one waterbody to another by attaching to watercraft, equipment and nearly anything that has been in an infested waterbody.

To prevent the spread of these mussels and other aquatic invasive species, people launching vessels at any waterbody are subject to watercraft inspections and are strongly encouraged to clean, drain and dry their motorized and non-motorized boats, including personal watercraft, and any equipment that contacts the water before and after use.

“Adult quagga mussels were discovered in Castaic Lake in Los Angeles County in August 2021. This detection is a reminder of how important it is to clean, drain, and dry your watercraft and equipment after every use to avoid spreading invasive species and help conserve California’s irreplaceable plant, fish and wildlife resources,” said California Department of Fish and Wildlife (CDFW) Invasive Species Program Manager Martha Volkoff.

Take the following steps both before traveling to and before leaving a waterbody to prevent spreading invasive mussels, improve the efficiency of your inspection experience, and safeguard California waterways:

• Clean – inspect exposed surfaces and remove all plants and organisms
• Drain – all water, including water contained in lower outboard units, live-wells and bait buckets, and
• Dry – allow the watercraft to thoroughly dry between launches. Watercraft should be kept dry for at least five days in warm weather and up to 30 days in cool weather.

CDFW has developed a brief video demonstrating the ease of implementing the clean, drain and dry prevention method. Additional information is available on the Division of Boating and Waterways website.

Media Contact:
Ken Paglia, CDFW Communications, (916) 825-7120