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2022-2024 News Releases

Boaters Asked to Help Fight Spread Of Invasive Mussels over Memorial Day Weekend
  • May 27, 2022
Invasive mussel on boat

As Californians gear up for another beautiful summer full of outdoors recreation, boaters are being asked to remember the importance of cleaning, draining and drying their watercraft to combat the spread of invasive quagga and zebra mussels.

Quagga and zebra mussels are invasive freshwater mussels native to Europe and Asia. They multiply quickly, 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.

Invisible to the naked eye, microscopic juveniles are spread from infested waterbodies by water that is entrapped in boat engines, ballasts, bilges, live-wells and buckets. Quagga mussels have infested 34 waters in Southern California and zebra mussels have infested two waters in San Benito County, 13 of which are boatable by the public.

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

“The California Department of Food and Agriculture (CDFA) operates border protection stations that inspect trailered watercraft entering the state,” said California Department of Fish and Wildlife (CDFW) Invasive Species Program Manager Martha Volkoff. “Early this year, the stations marked their two-millionth watercraft inspected, a milestone that represents a monumental contribution in preventing further introductions of mussels into the state. In addition to the border protection stations, water managers throughout the state continue to implement inspections at their waterbodies. Memorial Day is a great opportunity to spread the word to  boaters about the simple actions they should take in preparation for their next outing.”

“Boaters need to conduct the ‘Clean, Drain and Dry’ practice each time they enjoy recreating on waterbodies,” said California State Parks Division of Boating and Waterways Acting Deputy Director Ramona Fernandez.  “This responsible boating practice will help keep our water bodies free from invasive species, such as freshwater quagga and zebra mussels.”

Quagga and zebra mussels can attach to and damage virtually any submerged surface. They can:

  • Ruin a boat engine by blocking the cooling system and causing it to overheat
  • Jam a boat’s steering equipment, putting occupants and others at risk
  • Require frequent scraping and repainting of boat hulls
  • Colonize all underwater substrates such as boat ramps, docks, lines and other underwater surfaces, causing them to require constant cleaning
  • Impose large expenses to owners

CDFW advises boaters to take the following steps before leaving a waterbody to prevent spreading invasive mussels, improve the efficiency of their 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.

Please visit websites for CDFW and California State Parks for extensive information on invasive species, the harm they can produce, and how California boaters can provide crucial assistance in the fight against invasive mussels.

Travelers are also advised to be prepared for inspections at CDFA border protection stations. Inspections, which can also be conducted by CDFW and California State Parks, include a check of boats and personal watercraft, as well as trailers and all onboard items. Contaminated vessels and equipment are subject to decontamination, rejection, quarantine or impoundment.

CDFW, CDFA, State Parks and the California Department of Water Resources thank boaters for their continued and valuable cooperation in joining the fight against invasive quagga and zebra mussels.

Media Contacts:
Tim Daly, California Department of Fish and Wildlife, 916-201-2958
Steve Lyle, California Department of Food and Agriculture, 916-654-0462
Newsroom, California State Parks Division of Boating and Waterways,
Newsroom, California Department of Water Resources,

Categories: Invasive Species

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