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Invasive Mussels


The threat of infestation of invasive mussels in local waters is great. We need to do all we can to prevent their introduction. All boats entering valley reservoirs are now required to undergo inspection under a new program jointly funded by the Santa Clara Valley Water District and the County of Santa Clara. The program, instituted on May 23, 2008, is designed to prevent invasive zebra and quagga mussels from getting into the water through recreational boating.

The main function of Santa Clara Valley Water District reservoirs is storage of future drinking water for county residents. The public has been allowed access for recreational uses that do not harm the integrity of the water supply. Following the discovery of invasive zebra mussels in a neighboring county’s reservoir in January, 2008, a program of mandatory boat inspections, overseen by County Parks, was instituted.

Zebra and quagga mussels damage native ecosystems and water supply pipes and valves. Growing in thick blankets that clog pipes, pumps, valves, water intakes, trash racks, and boat engines, they are difficult to remove and are almost impossible to eradicate.

Zebra mussels were discovered in January 2008 in San Justo Reservoir in nearby San Benito County, the first time they had been found in a water body west of the Rockies. Related quagga mussels were discovered in southern California for the first time in 2007 and have spread quickly. These mussels attach to boats, aquatic plants, bait buckets and other water-recreation equipment and spread when these items are moved from infested waters to another water body. Their microscopic larvae can be transported in a live well, bilge or bait bucket. Boaters can take specific steps to avoid spreading invasive species.

Don’t spread invasive species

  • Inspect all exposed surfaces – small mussels feel like sandpaper to the touch.
  • Wash the hull of each watercraft thoroughly.
  • Remove all plants and animal material.
  • Drain all water and dry all areas.
  • Drain and dry the lower outboard unit.
  • Clean and dry all live-wells.
  • Empty and dry any buckets.
  • Dispose of all bait in the trash.
  • Wait five days and keep watercraft dry between launches into different fresh waters.

For more information on boating inspections, boating rules, park hours, and launch reservations, contact County Parks at (408) 355-2201 from 8:30 a.m. to 3:30 p.m. Monday through Friday, or on-line at www.parkhere.orgPark hours, inspection procedures and reservoir access will change with the seasons.