Quagga/Zebra Mussel News

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.

DWR has published a press release.

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. 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.

Looking for ways to keep your kids creatively engaged? We're accepting submissions for the 8th Annual California Invasive Species Action Week Youth Art Contest. This year's theme is "Be an Invasive Species Detective." We're looking for art that shows how young people can use their powers of observation to help stop the spread of invasive species. We encourage students to get creative with submissions and use any medium they'd like, including but not limited to drawing, painting, animation, and video.

The art contest is open to grades 2-12. Entries will be placed into three grade divisions and three winners selected from each division. Department of Fish and Wildlife staff will select one contestant to receive the Invasive Species Program Choice Award. Winners will be announced on CDFW's Facebook page during California Invasive Species Action Week, June 5-13, 2021.

Deadline: May 5, 2021

Submission instructions