Quagga/Zebra Mussel Prevention Program


Quagga and zebra mussels are harmful, highly invasive freshwater species that have been recently discovered in California waters. California’s resources agencies have stated that the further spread of quagga and/or zebra mussels in California waters could result in an environmental and economic disaster. Read more about their introduction into California.

Current infestations in California are limited to quagga mussel infestations in several reservoirs in southern California receiving water from the Colorado River and a zebra mussel infestation at one isolated reservoir in San Benito County. See a map of quagga and zebra mussel sightings. Their appearance has heightened concern that these species may infest other waterways in California.

Recent California legislation, AB 2065, has added a requirement to the California Fish and Game Code requiring owners and managers of reservoirs to assess the vulnerability of their reservoirs for the introduction of nonnative dreissenid mussel species (i.e., quagga and zebra mussels) and to develop and implement a program designed to prevent the introduction of these mussel species.

Environmental Concerns

In waters outside their native range, quagga and zebra mussels are harmful, highly invasive freshwater species. Once introduced, favorable growing conditions and the absence of any natural predators contribute to their rapid colonization and expansion. These mussels can have significant negative impacts to the natural environment, including:

  • disrupting aquatic food chains and ecological communities, and
  • displacing native aquatic species.

Recreational Concerns

PG&E operates many lakes and reservoirs for the purpose of public recreation and the production of clean, renewable hydroelectricity. Impacts to personal and public property infested with quagga and zebra mussels can be significant, including:

  • impacting recreational activities, including sportfishing,
  • littering beaches with sharp shells,
  • emitting a foul odor as the mussels decompose,
  • fouling boats, docks, ramps and other marina facilities, and
  • damaging boat engines and steering components.

PG&E Facility/Operation Concerns

In addition to the effect these species can have on local ecosystems and recreational activities, an infestation of either quagga or zebra mussels can hinder water delivery. The mussels’ capacity to clog or foul pipes, pumps, water intake structures, power plant intakes, cooling systems, and fish screens can impact the ability of water agencies to deliver drinking water and utilities to efficiently provide power to its customers. See more images.

PG&E’s Mussel Prevention Program

To protect PG&E assets and the ecological integrity of the waters PG&E manages, and to comply with AB 2065, PG&E has implemented an infestation prevention program at its reservoirs and waterways. This program includes public education, monitoring, and management of those recreational, boating, and fishing activities that are permitted. PG&E will work with local, state and federal agencies, other utilities and recreational facility operators to ensure that the program is effective.

To help prevent the infestation of quagga and zebra mussels, PG&E began implementation of a program in January 2009 that includes the following elements:

  • a vulnerability assessment of PG&E lakes and reservoirs to determine the potential for mussel infestation,
  • a public education program to inform reservoir users of the infestation risk and measures to prevent an infestation,
  • monitoring for early detection of these mussels, and
  • management of recreational, boating, and fishing activities, as may be needed.

California Department of Fish and Game Boat Inspection Guidelines

These mussels will clog water pipes, coat piers, and ruin boat motors. Transferring a boat from an infested waterbody to another could spread the mussels. Boaters should check their boat, trailer and vehicle every time their boat is taken out of the lake or reservoir.

When leaving the water:

  • Inspect all exposed surfaces - small mussels feel like sandpaper to the touch.
  • Wash the hull of each watercraft thoroughly.
  • Remove all plant 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 5 days in hot weather and up to 30 days when cool and moist. Keep watercraft dry between launches into different fresh waters.

For more information, boat owners can download the California Department of Fish and Game’s A Guide to Cleaning Boats and Preventing Mussel Damage.

Report quagga and zebra mussel sightings to the California Department of Fish and Game’s mussel hotline: 1-866-440-9530. Please visit the CDFG quagga and zebra mussel webpage for more information.

PG&E appreciates your vigilance and support to keep California’s waters free of invasive mussels.

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