On April 9, California Department of Wildlife (CDFW) Invasive Species Program staff detected 12 veligers using cross-polarized microscopy in a plankton tow sample collected on February 23 at Castaic Lagoon, which is downstream of Castaic Lake. On April 10, CDFW staff also detected 33 veligers in a plankton tow sample collected on March 30 in Castaic Lagoon. The veligers in Castaic Lagoon have been confirmed to be quagga mussel via PCR and DNA sequencing.
Castaic Lagoon is located near the unincorporated community of Castaic in Los Angeles County. It is immediately downstream of Castaic Lake and used for non-powered boating, canoeing, and swimming. Castaic Lake and Castaic Lagoon are part of the State Water Project and of the Castaic Lake State Recreation Area. The California Department of Water Resources (DWR) is the water manager for Castaic Lagoon and the Los Angeles Department of Parks and Recreation manages recreational access.
Adult quagga mussels were discovered in Castaic Lake in 2021. Pyramid Lake, known to have quagga mussels since 2016, is upstream of Castaic Lake. Castaic Lagoon is immediately downstream of Castaic Lake and has been presumed to be exposed to mussels.
Castaic Lagoon discharges to Castaic Creek, a tributary to the Santa Clara River. Quagga mussels were discovered in the Santa Clara River downstream of Castaic Creek below the confluence with Piru Creek in 2017.
For questions that are specific to DWR’s response, please contact Maggie Macias, DWR Information Officer at (916) 902-7405. For questions regarding CDFW’s response, please contact CDFW’s hotline at (866) 440-9530.