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 About This Project


The County of Lake Water Resources Department launched this project in December of 2022 to develop an Invasive Mussel Introduction Rapid Response and Containment Transition Plan for Clear Lake, in Lake County, California. The overall goal for the project is to improve the current aquatic invasive species prevention program while preparing for an invasive quagga or zebra mussel (“QZ”) introduction into Clear Lake, or Lake County. Preparing for an introduction by developing a containment strategy that can be implemented quickly and efficiently will reduce local impacts as well as prevent the spread of invasive mussels in northern California and other uninfested western waters. This plan will build on the Lake County Quagga and Zebra Mussel Prevention Plan.



Clear Lake is the largest natural freshwater lake located entirely in California and consistently ranks in the top 10 list of  bass fishing lakes by Although Clear Lake provides ideal water quality conditions and habitat for an established mussel introduction, Clear Lake currently has no quagga or zebra (QZ) mussels. The county relies on a prevention program supported primarily through state grants as well as sales of local mussel stickers.


Clear Lake provides drinking water to 60% (~40,000) of the population of Lake County and provides a reliable water source for nearby agriculture within the basin and downstream through Yolo County and to the California Central Valley. Lake County is a recognized disadvantaged community comprised of low-income and tribal communities. Clear Lake is the county's most valuable asset, providing economic and ecological stability to the entire region. The popularity and accessibility of Clear Lake combined with its ideal water quality conditions suitable for mussel establishment, make the risk of an invasive mussel invasion extremely high.


There are currently 11 free public boat launches and five marinas and harbors are open year-round to trailered vessels ( Lake County Department of Public Services maintains 13 free public swim beaches on Clear Lake. California State Parks owns and operates the Clear Lake State Park that has both beach access and boater launch facilities, and Anderson Marsh State Historic Park, which boasts non-motorized water trails. Both of these parks are big draws for visitors to the lake. In addition to 11 public access facilities, there are at least 20 private resorts with launch ramps, and numerous private access points, totaling 749 private or public access points on the lake - about 450 are motorized boat accessible. Clear Lake is a fishing destination that hosts more than 100 tournaments annually from local club contests to large-scale commercial events with more than 1,000 entries. 


Proper preparation for a QZ introduction, using targeted rapid response planning, would ensure that the natural resources and economies dependent on Clear Lake are minimally impacted. A containment transition plan would simultaneously reduce costs for short-term response actions and reduce the long-term costs and impacts from the potential spread of mussels to other waters throughout northern California and the western United States. Development of a plan, and course of action now, will allow the District, and partners, to plan and prepare, financially and logistically, for the unfortunate event that an introduction does occur. The project “plan” will include two main components:

  • Rapid Response Strategy; and 

  • Transition to a Containment Program, to be implemented if a QZ mussel introduction is detected and confirmed in Clear Lake, or other publicly managed water bodies in the County.

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