Posts Tagged: zebra mussels

Integrated aquatic pest management shows promise

Carolynn Culver, a research scientist at UC Santa Barbara and an California Sea Grant extension specialist, is researching whether native sunfish can be used in place of toxic chemicals to reduce invasive mussel larvae and other pests in Southern California lakes and reservoirs, reported Sonia Fernandez in the USCB online magazine Futurity.

Quagga and zebra mussels are two of the most devastating aquatic pests in the United States. The small freshwater mussels grow on hard surfaces such as water pipes, and can cause major problems for water infrastructure. First appearing in North America in the 1980s, and in California in 2007, mussel management with chemicals has been shown to impact water quality.

“Commonly used mussel control methods are problematic for San Diego reservoirs since they are primary water supply reservoirs,” said study coauthor Dan Daft, a City of San Diego water production superintendent and biologist.

The researchers found that when one species of sunfish, bluegill, was penned up in an area where mussels occur, it could significantly reduce microscopic larvae and newly settled young mussels on surfaces within the pen, and on the pen itself. This method could be one key piece of an integrated pest management strategy, and provides a nonchemical method for targeting early life stages of the mussels, which are hard to detect.

In another study aimed at protecting water from toxic chemicals, Culver worked with UC Cooperative Extension advisor emeritus Leigh Johnson to study hull cleaning practices that can be alternatives for using copper-based paints, which leach copper into water.

The team showed that frequent, minimally abrasive, in-water hull cleaning was effective and did not cause an increase in fouling as reported for other hull cleaning practices. Results from the study, along with other research findings, informed the development of an integrated pest management framework that boaters can adapt to different regions and specific needs.

“It's not a one-size-fits-all approach — it's adaptive,” Culver said. “Boaters can tailor it to local environments, regulations and boating patterns, and it can be applied in areas where toxic paints have been restricted, as well as where they continue to be used. It can help to keep boat hulls clean, while reducing impacts on water quality and transport of invasive species — three issues that often are not considered together.”

 Read more about UCCE quagga and zebra mussel research and extension.

Zebra mussels and quagga mussels threaten California water systems

Some of California’s many introduced species — plants, animals, insects, and aquatic organisms — have marked impacts on ecological systems.

Invasive aquatic organisms can impact fish, shorebirds, marsh plants, and other wetland species, and alter functions of lakes, watersheds, floodplains, and coastal ecosystems.

Estuarine ecologist Ted Grosholz, a UC Davis professor and Cooperative Extension specialist in the Department of Environmental Science and Policy, is an expert on invasive species and addresses outreach education on zebra mussels and quagga mussels.

These two invasive, freshwater Eurasian mussels—zebra mussels and quagga mussels — could have a profound impact on California’s lakes and water distribution systems.

Both quarter-sized mussels showed up in California about six years ago. They attach themselves to water conveyance systems — pumps, pipes, dams, aqueducts, and fish hatcheries — and proliferate. According to Grosholz, “our drinking water and agricultural irrigation systems could be shut down quickly by these organisms.”

Los Angeles water districts are coping with the mussels, which are in Southern California watersheds, and reservoirs and canals of the Colorado River. The larval stage of the mussels disperses readily in water, so it gets moved around easily. There is tremendous concern about their potential spread into Lake Tahoe, and they have recently shut down a reservoir near San Jose. These mussels have cost the state tens of millions of dollars.

Zebra and quagga mussels pose a serious ecological threat in California. In the Great Lakes, where they became established 25 years ago, they have removed phytoplankton — a food source for juvenile fish — thereby impacting the food web. They have also concentrated the environmental contaminant botulism, resulting in massive kills of diving ducks and shorebirds.

Aquatic invasive species are moved long distances by ships — in ballast water, hulls and attached to ships’ surfaces. Within California they can be moved by recreational and fishing boats, trailers and other equipment.

“Once aquatic species are introduced, the cat is out of the bag — they spread easily, and they’re very difficult to control,” notes Grosholz.

Since the state doesn’t have the resources to adequately enforce zebra and quagga mussel control, areas such as Clear Lake and Fallen Leaf Lake are establishing local mandatory vehicle and boat inspection programs.

Grosholz works closely with resource agencies and other organizations to develop programs aimed at identifying and reducing the spread of invasive aquatic organisms. “It’s important to increase awareness of these species because they’re such a problem,” says Grosholz. “Their impact on ecosystems is big, and early control is very important.”

To read more about invasive aquatic species, including zebra and quagga mussels, see:

CA&ES Outlook magazine, pages 4–7

Quagga/Zebra Mussel Invasion, UC Cooperative Extension Coastal Resources

Quagga and Zebra Mussels, California Dept. of Fish and Game

Quagga and Zebra Mussel Prevention Program, San Luis Obispo County, California

Quagga and Zebra Mussel, Calif. Dept. of Boating and Waterways

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