Quagga Mussels:
Why You Should Care
In 2007…
The first quagga mussel population was found in the Colorado River system in Lake Mead. Since 2007, these invasive fresh water mollusks have spread to 45 waterbodies in California. They are still getting closer. The quagga/zebra mussel threat is still very real for Big Bear Lake. Quagga mussels have been sighted as close as the Upper San Gabriel River, Lower Piru Creek, Pyramid Lake, Castaic Lake, and the Angeles Tunnel which connects Lake Silverwood to Lake Perris. Unfortunately many believe that the invasion of quagga or zebra mussels into Big Bear Lake is inevitable, and without your help it may be. However, the District believes that its quagga prevention program, its staff, and boaters and visitors like you can keep the mussels at bay. The District has received grant funding from the Division of Boating and Waterways since 2014 to help bolster its quagga/zebra mussel infestation prevention program. The District has installed two new decontamination units and an additional catchment drain pad at the East Launch Ramp to process double the amount of decontaminations. The District has been able to purchase new education material and signage to help spread the word about the mussels’ threats to new and returning visitors. The District also holds an annual class to certify anyone interested to become a Level I watercraft inspector - - all marina staff and lake front homeowners with launch ramps are required to attend!
The District still needs your help in defending the lake from quagga and zebra mussels. All vessels should arrive at the lake clean, drained, and dry. This means not only motorized boats but kayaks, canoes, float tubes, stand-up paddle boards, and inflatable kayaks and rafts. These non-motorized vessels require an inspection and a lake use permit which can be provided at any of the launch facilities on Big Bear Lake. Please do not launch your non-motorized vessel without an inspection by District or marina staff. It is quick and easy and it ensures YOU are not the person who ruins Big Bear Lake forever by introducing quagga or zebra mussels!
New Infestations in 2021
From the California Department of Fish and Wildlife
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May 2021 - Santa Margarita River
May 20, 2021 - Summary of Discovery
On May 20, 2021, Rancho California Water District (RCWD) notified the California Department of Fish and Wildlife (CDFW) that RCWD discovered adult quagga mussel in the Santa Margarita River, Riverside County, approximately 1,000 feet downstream from the San Diego Pipeline #5 WR-34 Discharge Site. San Diego Pipeline #5 transports water from Lake Skinner, a lake known to have quagga mussels (Dreissena rostriformis bugensis) since August 2007. Water from Lake Skinner is chlorinated, transported via San Diego Pipeline #5, then de-chlorinated at the WR-34 Discharge Site before being discharged into the Santa Margarita River. Metropolitan Water District of Southern California (MWD) manages Lake Skinner, the chlorination, and the pipeline, while RCWD manages the dichlorination and discharge into the Santa Margarita River.
Santa Margarita River is west of the CA I-15 Highway in Temecula. Murrieta Creek and Temecula Creek merge to form the Santa Margarita River. The WR-34 Discharge Site is located just below the confluence of Murrieta Creek and Temecula Creek, and flows directly into the Santa Margarita River.
On May 21, CDFW Region 5 and 6 staff conducted surface surveys for presence/absence of mussels in Murrieta Creek working downstream to the Upper Santa Margarita River to the WR-34 discharge site. Adults were detected downstream of the WR-34 discharge site. No adults were discovered above that location. CDFW laboratory has visually identified the specimens as quagga mussels and confirmed that identification with PCR analysis. CDFW staff will conduct additional surface surveys in Santa Margarita River and at Lake O’Neill.
In December 2014, the US Bureau of Reclamation (USBR) notified CDFW of a positive detection from an October plankton tow sample collected near the same area of the Santa Margarita River. Follow up sampling by USBR, CDFW, and MWD in 2015 confirmed the presence of veligers in multiple samples, and several unpreserved samples were examined and no veligers exhibited movement. In June 2017 CDFW analyzed samples collected by RCWD and no mussels were detected.
For questions that are specific to RCWD, please contact Eva Plajzer, P.E., Assistant General Manager, RCWD, at (951) 296-6910. For questions regarding CDFW's response, please contact Dominique Norton at (916) 203-4499.
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August 2021 - Castaic Lake
August 30, 2021 - Summary of Discovery
On August 6, 2021, a Castaic Lake park visitor reported finding one adult quagga mussel while kayaking in Castaic Lake (Los Angeles County). The specimen was sent to California Department of Fish and Wildlife (CDFW) for laboratory analysis which confirmed via genetic analysis the species identification as quagga mussel.
On August 17, 2021, Department of Water Resources (DWR) and CDFW staff discovered a ½ shell (dead) quagga mussel and a full shell (dead) quagga mussel along the shoreline of Castaic Lake.
On August 24, 2021, CDFW staff discovered a full shell (dead) quagga mussel along the shoreline of Castaic Lake.
These discoveries constitute the detection of adult mussels at Castaic Lake, thereby triggering management actions be taken to control mussels within the system.
Pyramid Lake, known to have quagga mussels since 2016, is upstream of Castaic Lake. Castaic Lagoon is immediately downstream of Castaic Lake, and therefore is presumed to be exposed to mussels.
To date, DWR and CDFW have not detected larval veliger-stage mussels in Castaic Lake during routine monitoring. CDFW will continue to work with DWR to delineate the population.
DWR, the owner and operator of Castaic Lake, is taking steps to implement a containment program. Los Angeles Department of Parks and Recreation, the recreation manager, began implementing exit inspections at Castaic Lake on August 13, 2021, to prevent the movement of quagga mussels. Boaters at these waterbodies, as well as all other waterbodies, should continue to clean, drain, and dry their watercraft and equipment after every visit.
For questions that are specific to DWR’s response, please contact Maggie Macias, DWR Information Officer, (916) 820-7662. For questions regarding CDFW’s response, please contact CDFW’s hotline at (866) 440-9530.
Funding for quagga and zebra mussel infestation prevention activities has been provided through an agreement with the California State Parks Division of Boating and Waterways. The contents of this web page do not necessarily reflect the views and policies of the California State Parks Division of Boating and Waterways, nor does mention of trade names or commercial products constitute endorsement or recommendation of their use.