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Two invasive mussel species pose a threat to the environment and water supply in California. The quagga mussel, Driessena bugensis, and zebra mussel, Driessena polymorpha, were detected in California water bodies in 2007 and 2008. Together, the are also known as invasive Eurasian mussels. 

These species have great potential to cause ecological harm by modifying aquatic habitats. They reproduce rapidly and reach very high densities. Thus, they compete for space with native species, and because they filter phytoplankton out of huge volumes of water, they can change the physical and biological properties of the ecosystem.

They may also cause significant economic harm by clogging pipes and covering infrastructure from boat engines and docks to dam gates and irrigation channels.

More information

Quagga/zebra mussels in California
For information about Eurasian mussels and other invasive species in California, and to report sightings, start with the California Department of Fish and Wildlife at https://wildlife.ca.gov/Conservation/Invasives/Quagga-Mussels
You may find local information by contacting your lake or water supplier.
Visit UC ANR's Aquatic Invasive Species Page for more information about this and other aquatic invaders. 


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UC Resources

Interested in starting a detection program? Check out our Early Detection Monitoring Manual for Quagga Mussels! 

Looking for guidance on eradication and control? See CA SeaGrant's Quagga and Zebra Mussel Eradication and Control Tactics Technical Report

This practical report explains how to use an Integrated Pest Management (IPM) approach and specific tactics for eradicating and/or controlling invasive dreissenid (quagga and zebra) mussels in lakes and reservoirs. It covers how to develop and get started on a management strategy, manual & mechanical removal, oxygen deprivation, chemical application, emerging technologies, and an overview of permitting and regulatory processes.