Boats leaving Pyramid Lake and Castaic Lake are subject to restrictions to help prevent the spread of quagga mussels, which were discovered last week in a tunnel that connects the two Los Angeles County lakes, the California Department of Water Resources (DWR) announced Thursday.

Effective Thursday, boats are subject to inspection as they leave Pyramid Lake and Castaic Lake and Castaic’s Lower Lake Lagoon.

Boats will be inspected by the Los Angeles County Parks and Recreation Department to ensure all water is drained from outboards, bilges, live-wells and any other areas where water may have collected.

As with boating anywhere in California, it is advised that boaters contact the destination waterbody so they are informed of any inspection requirements before their arrival. As a general practice, boats and equipment should be cleaned, drained and dried after every use to prevent spreading invasive species.

Boats leaving Pyramid and Castaic lakes will not be granted a “clean boat” tag, which normally is attached to boats upon departure. The tag is an indicator that the boat has only been used in mussel-free lakes and may not require inspection prior to entering other bodies of water, depending upon a lake’s specific launching requirements.

Additionally, the California Department of Fish and Wildlife (CDFW) urges other waterbody managers with quagga prevention programs to consider Pyramid Lake, Elderberry Forebay, Castaic Lake and Castaic Lagoon as infested waters. Watercraft originating from these waterbodies should be considered high-risk and managed accordingly.

The quagga mussel is a small, non-native freshwater mollusk that DWR had successfully prevented from infesting the State Water Project since the species was first discovered in California in 2007.  The mussels, native to the Ukraine, pose an ecological threat to California’s native species and can colonize hard surfaces, clogging water intakes, screens and pipes.

DWR found six adult mussels on December 8 during an inspection of the Angeles Tunnel, which connects Pyramid Lake to the Elderberry Forebay and nearby Castaic Lake. CDFW has concluded Pyramid Lake is infested and both Elderberry Forebay and Castaic Lake are presumed infested.

DWR has found no evidence of mussel reproduction, and no larval or “veliger” stage mussels have been found in Pyramid Lake or Castaic Lake during DWR’s routine monthly veliger detection monitoring. No young sub-adult mussels were found in the tunnel, and while no mussels have been found in Castaic Lake, infestation there is presumed. Both lakes are actively monitored each month.

CDFW has permitted black bass tournaments in Castaic and Pyramid lakes beginning in January. At this time, these tournaments will proceed. When tournament permits are issued, special conditions are required of the permittee, including boat inspections before entering new waterbodies. The boating restrictions above will be required for all tournament participants.

In addition, tournament organizations and participants must comply with all federal, state and local laws, regulations and ordinances pertaining to the spread of quagga mussels. These laws include additional responsibility for the tournament organizer and participants to properly clean, drain and dry boats before and after the tournament, and educational briefings and literature must be provided to all participants.

CDFW has authority to take enforcement action for any violation of FGC section 2301 related to the transportation of quagga mussels.

The Boat Cleaning Guide Book can be found at https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=4957 .