A particularly worrisome species of mussel has entered North America for the first time through the Sacramento-San Joaquin River Delta, triggering what many call an immediate threat to California’s most important watersheds.
Golden mussels, invasive freshwater bivalves that have devastated ecosystems and critical water infrastructure in other parts of the world, were recently discovered near Stockton Harbor. Limnoperna fortunei also appear to have found their way several miles downstream to O’Neill Forebay of the San Luis Reservoir, where Merced County authorities quickly conducted genetic testing.
“The species poses an immediate and significant threat to the ecological health of the Delta and all state waters, water systems, infrastructure, and water quality,” according to a public alert the California Department of Water Resources and the California Department of Fisheries. and wildlife. “This discovery is the first known occurrence of golden mussels in North America.”
These mussels likely infiltrated California by ship from an international port and are likely to spread throughout the Delta and through water infrastructure associated with the Delta, officials said in a statement. “Without containment, golden mussels are likely to spread to other freshwater bodies in California, as well as other ports and inland waters in North America and abroad.”
These tiny, dark yellowish molluscs, native to rivers in China and Southeast Asia, have already wreaked havoc in South America and kept U.S. officials and environmentalists on high alert for years. In each country where mussels have taken over, the initial introduction also appears to have come from ships—on hulls or from the discharge of ballast water.
And in most of these cases elsewhere, the golden mussel’s range expanded rapidly upstream or downstream from the point of introduction – usually in a port, then through local pathways of human intervention, have indicated those responsible.
A species of both freshwater and brackish water, the golden mussel can tolerate wide ranges of salinity levels, temperature and pH, and can travel much further than one might think. Shortly after fertilization, the larvae become mobile and are able to swim in a coordinated manner dispersing throughout the water column.
Acquisitions of golden mussels from other countries have shown that the species can grow in clumps or colonies containing up to 80,000 to 200,000 organisms per square meter.
Wildlife officials have noted that the golden mussel can survive in waters considerably lower in calcium than the quagga mussel or zebra mussel, which has caused many problems in California’s lakes and reservoirs, as well as the Great Lakes region and many other countries. lakes across the United States.
In addition to disrupting the ecological balance of an entire body of fresh water, golden mussels pose a significant threat to California’s water infrastructure. These mussels can clog critical water intakes and fish screens and also clog main water supply lines.
Agricultural irrigation and power plant operations could also be significantly hampered, and if past mussel infestations are any indication, golden mussels could also seriously harm boating and recreation by encrusting docks, engines and steering equipment.
In California, a team of state, local, and federal agencies are actively monitoring and coordinating next steps to prevent the species from spreading further in California and beyond. Authorities have called on anyone working or recreating in California’s lakes and rivers to clean, drain and dry their personal watercraft and equipment whenever they are removed from a body of water. (The California State Parks Division of Boating and Waterways has a web page detailing how to “clean, drain and dry” a boat.)
“This simple measure has helped prevent the spread of quagga and zebra mussels and is equally effective in stopping the terrestrial spread of golden mussels,” officials said.
Those who observe suspected golden mussels in California are asked to file a report through the CDFW Invasive Species Program, either by completing the online form or sending an email to invasives@wildlife.ca.gov or by calling (866) 440-9530. Please note that authorities request that these citizen reports include the specific location of the sighting and at least one clear close-up photograph of the mussel.
