Pyramid Lake infested with Quagga Mussels, Castaic Lake feared next

Quagga Mussels found in Lake Piru in December 2013. File photo by Dan Watson, The Signal

Pyramid Lake is now infested with ecosystem-altering Quagga Mussels after state officials found six of the non-native freshwater mollusks Thursday in a tunnel that connects the lake with another body of water along the state’s water delivery system.

In short, the invasive mussels can alter the natural life systems of a lake.

Quagga mussels can clog water systems, alter food webs in ecosystems and damage boat engines, per the California Department of Fish and Wildlife.

The discovery now poses a threat to Castaic Lake, downstream from Pyramid Lake, as it is presumed infested with the mussels, officials with the department announced in a news release.

The discovery prompted officials with the California Department of Fish and Wildlife to conclude that Pyramid Lake must be considered infested with the invasive species.

As a result, all boats entering and leaving Castaic Lake will now be required to undergo an inspection protocol for precautionary reasons, officials with the Los Angeles County Department of Parks and Recreation announced Saturday.


Quagga Mussels found in Lake Piru in December 2013. File photo by Dan Watson, The Signal.
Quagga Mussels found in Lake Piru in December 2013. File photo by Dan Watson, The Signal.

All boats entering Castaic Lake will continue to be inspected to ensure they are completely dry.

Beginning Saturday, boaters leaving the lake have been required to remove the plug in their vessels to completely drain all water, to prevent the spreading of the invasive mussel as mandated by the California Department of Water Resources and the state Department of Fish and Wildlife at all infested lakes.

A small, non-native freshwater mollusk, state officials have successfully prevented the Quagga Mussels from infesting the State Water Project, the state’s water delivery system, since the species was first discovered in California in 2007.

On Thursday, however, six adult quagga mussels were found in the Angeles Tunnel, a connector between Pyramid Lake and Elderberry Forebay, two components of the State Water Project north of Los Angeles.

Elderberry Forebay is a small reservoir which was partitioned from Castaic Lake in 1974 to store water for pumped-storage hydroelectricity generation.

Officials with the Department of Water Resources discovered the mussels during a scheduled inspection of Angeles Tunnel.

They said there is no evidence – early stage or otherwise – of mussel reproduction found in Pyramid Lake during the department’s routine monthly monitoring.

No young sub-adult mussels were found in the tunnel, and no mussels have been found in Castaic Lake. Both lakes are actively monitored each month.

The “infested” determination for Pyramid Lake means boats must be inspected and thoroughly washed upon leaving the lake. It also means those boats will not be granted a “clean boat” tag that normally is given to boats when they leave water bodies that do not contain quagga mussels.

The tag is a visual sign that the boat does not require inspection prior to entering other bodies of water.

State officials have notified other water agencies about the discovery.


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