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.