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Quagga mussels discovered in Pyramid Lake


With the discovery of quagga mussels in Pyramid Lake in northern Los Angeles County this past week, there are now 32 waters in Southern California certified to have the invasive species. Those waters include the entire Colorado River and its aqueduct system, most of the lakes and reservoirs in San Diego, Riverside, and Orange counties, and Piru Lake in Ventura County.

This is the first time the quagga mussels have been discovered in the state water project. There were just six adult quagga mussels found on Dec. 8 in the Angeles Tunnel, which connects Pyramid Lake and Elderberry Forebay. With the find, the Department of Fish and Wildlife has concluded that Pyramid Lake must be considered to have the mussels now, and it is a certainty they will also eventually end up in the forebay and Castaic Lake, both which are downstream from Pyramid.

The quagga mussel is a small, non-native mussel that was first discovered in California when they were found in Lake Havasu in 2007, with additional waters being added to the list every year since.

According to the Department of Water Resources, the “infested” determination for Pyramid Lake means boaters at Pyramid must now jump through the quagga hoops. All boats from Pyramid must now be inspected and thoroughly washed upon leaving the lake. It also means those boats will not be granted a “clean boat” tag. That tag is given to boats when they leave water bodies that do not contain quagga mussels, and it is a visual sign that the boat does not require inspection prior to entering other bodies of water.

Since their discovery, quagga mussels have set in motion a series of expensive lake surveys throughout the state, and they have led to draconian boat inspection measures and boating restrictions that have been a component in the steady and dramatic decline in recreational and fishing boat use in fresh waters in this region.

The quagga mussel is feared because it reproduces rapidly and it clogs water transport facilities, requiring expensive maintenance.

It is also feared the mussels will harm sportfisheries throughout the region. They are filter feeders and there is concern they can have negative impacts on the bottom of the food chain, which will cause a ripple effect and led to declines in fish populations. The mussels are credited with clearing up the water in Lake Havasu because they feed on algae and phytoplankton. However, there little empirical evidence to prove that fisheries are being negatively impacted, only speculation. In fact, just the opposite has been show to occur in the Great Lakes where many warm water species are actually benefiting from the mussels.

There is also anecdotal evidence they have been a boon to the redear sunfish population in Lake Havasu, where numbers of redears and the size of the fish has increased because they feed on the mussels. With the nearly endless food supply, the redear are growing to record sizes. The current world record was caught at Havasu just two seasons ago.

But, the line from the fishery scientists is that the sky is falling. The sky was falling when whirling disease was discovered in trout fisheries in California in the 1980s. It didn’t fall, and it has been hard to see any negative impacts in whirling disease-infected waters. Then the sky was falling when New Zealand mud snails were discovered in the Eastern Sierra. One biologist said he believed it would be the end of quality trout fishing in the region. But the sky wasn’t falling then either, and the New Zealand mud snails have proven to have very, very minor impacts and those only in localized spots.

Now the sky is falling again as the march of quagga mussels (and a close relative the zebra mussel) is spreading across the state’s waters.

Well, maybe the sky is falling this time. Maybe our fisheries are doomed. But no one will blame you if you are skeptical.

What is known is that no one has measured any significant declines in California fisheries because of quagga mussels, and water agencies have been able to keep the water coming to our taps.

What is also known is that annual fishing license sales declined by 200,000 between 2007 and 2015, going from 1.28 million to 985,000. Now we all know that correlation is not causation. But license sales had increased for five consecutive years up until 2007, but they have declined every year since. Certainly quagga mussels and the restrictions on fishing boats they have caused are not the only reason for the decline, but they are certainly one of many factors.

A little over a decade ago, it was pretty common for a fisherman with a trailer-able boat to fish Havasu one weekend, Lake Perris the next, Lake Casitas the next, and Lake Crowley the next -- and launch and fish all those waters with no restrictions. Quagga mussels have changed all that and the restrictions are just making life more miserable for anglers and boaters, not stopping the spread of quagga mussels. Today, there are expensive inspections, dry dock requirements at some waters (even if the inspection comes back clean), or costly cleaning regimes.

With so many waters now infected with quagga mussels, instead of continuing the inspections and cleaning mandates for waters that now have the mussels, how about the state issue a boat “stamp” that allows boats to be used in ALL infected waters without the hassles and costs. And how about, every time a new lake is added to the “infected” list, that water is opened up to all boats that operate on infected waters.

If the state did that, do you realize where bass (and other) anglers could once again fish without worrying about restrictions? Here’s a list of popular fishing waters in this region that are already quagga-positive. They include Lake Havasu (and all of the other Colorado River reservoirs, backwaters, and aqueduct systems), Lake Skinner, Dixon Lake, Lower Otay Reservoir, San Vicente Reservoir, Murry Reservoir, El Capitan Reservoir, Lake Jennings, Irvine Lake, Anaheim Lake, Lake Poway, Lake Cahuilla, Lake Piru, and now Pyramid Lake.

And more waters are and will be added each year.

Are quagga mussels causing the sky to fall? Probably not for fisheries or water deliveries. But the quagga restrictions might be another nail in the coffin of sportfishing in the Golden State.


[Jim Matthews is a syndicated Southern California-based outdoor reporter and columnist. He can be reached via e-mail at or by phone at 909-887-3444.]

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