As if the imperiled Sacramento-San Joaquin River Delta didn't already face a number of problems, the California Department of Water Resources staff has discovered a new invasive species, the golden mussel, in the Sacramento-San Joaquin River Delta while conducting routine operations.
The non-native freshwater bivalve (Limnoperna fortunei) was found in the Port of Stockton. Suspected golden mussels have also been identified at O’Neill Forebay in Merced County and are currently undergoing genetic testing for confirmation, according to a statement from the CDFW.
“This discovery is the first known occurrence of golden mussels in North America,” said Steve Gonzalez from the California Department of Fish and Wildlife. “The species poses a significant immediate threat to the ecological health of the Delta and all waters of the state, water conveyance systems, infrastructure and water quality.”
“In waterways where this species is present, heavy encrustations of golden mussels have blocked municipal and industrial water intakes, necessitated ongoing biofouling removal, harmed native species in the ecosystem, increased water clarity due to intense filter feeding, and diminished water quality,” Gonzalez stated.
Gonzalez said the Golden mussels were likely introduced to California by a ship traveling from an international port.
“They are likely to spread throughout the Delta and through the water conveyance systems associated with it. Without containment, golden mussels are likely to spread to other freshwater bodies in California, and to other ports and inland waters of North America, and abroad,” he said.
Following the initial discovery of golden mussels in the Port of Stockton, Gonzalez said observations of additional mussels have been made on monitoring equipment downstream. Species confirmation is pending for these organisms.
He noted that golden mussels are similar in appearance, biology, and impacts to quagga and zebra mussels and are a “continued priority for prevention and containment in inland waters of Southern California and across the state.”
Golden mussels are native to rivers and creeks of China and Southeast Asia. They are known to be established outside of their native range in Hong Kong, Japan, Taiwan, Brazil, Uruguay, Paraguay and Argentina, according to Gonzalez.
“The initial introductions to these countries were also likely the result of ships from biofouling on the hulls and/or ballast water release. In most cases, the invaded range has expanded upstream from the point of introduction and inland from ports through local, human-mediated pathways. Within the invaded range significant impacts are widely documented resulting from the dense colonization of golden mussels on hard surfaces,” said Gonzalez.
The discovery of the golden mussel comes at a time when the San Francisco Bay-Delta is in its worst-ever crisis. Imperiled Central Valley salmon populations and Delta smelt, longfin smelt and other fish species have collapsed, due to massive water exports to corporate agribusiness and Southern California water agencies, combined with the impacts of toxics, pollution and invasive species. No Delta smelt, once the most abundant fish species in the Sacramento-San Joaquin River Delta, have been caught for six years in the California Department of Fish and Wildlife’s Fall Midwater Trawl Survey.
In addition, a weekly survey by the US Fish and Wildlife Service targeting Delta smelt caught only one smelt this summer. “A late April IEP juvenile fish survey (the 20-mm Survey) caught several juvenile Delta smelt in the same area,” noted scientist Tom Cannon in his blog on the California Sportfishing Protection Alliance website: calsport.org/...
All salmon fishing has been closed in California ocean and river waters over the past two years — and the season is likely to be closed next year, due to the collapse of the Sacramento River and Klamath River fall Chinook salmon populations. A shockingly low number of fall run Chinook salmon have returned this fall to Coleman National Fishery, located on Battle Creek, a tributary of the upper Sacramento River. A total of 3.9 million green eggs have been taken to date at the hatchery, only a fraction of the typical 20 million eggs harvested during the spawning season.
Gonzalez said the California Department of Fish and Wildlife (CDFW), California State Parks, California Department of Water Resources (DWR), U.S. Fish and Wildlife Service, Bureau of Reclamation, and other state, federal, and local agencies regularly coordinate through the Aquatic Invasive Species program. This partnership aims to limit the spread of invasive species in California’s waterways, which cause damage to native species and the ecosystems they need to survive.
“The California Natural Resources Agency and its partners call upon everyone working and recreating in waters of the state to clean, drain and dry watercraft and equipment every time it is removed from a waterbody. This simple measure has served to prevent spreading quagga and zebra mussels and is equally effective in stopping the overland spread of golden mussels. DWR is now conducting boat inspections at O’Neill Forebay in an effort to reduce the spread of aquatic invasive species,” said Gonzalez.
CDFW is continuing to work with state, local, and federal agencies to enhance monitoring efforts, communicate additional detection and response information, and coordinate on potential next steps.
“I think the solution to stopping the speed of golden mussels lies with all of us, the people of California,” said Gonzalez. “We must clean, drain and dry watercraft. This strategy has worked for slowing the spread of quagga and zebra mussels in California.”
Please report organisms observed in California suspected to be golden mussels to CDFW’s Invasive Species Program. Include the specific location of the observation, and at least one clear close-up photograph of the organism, and your contact information. Submit reports via one of the following options:
Online at https://wildlife.ca.gov/Conservation/Invasives/Report
Via email to invasives@wildlife.ca.gov
Via telephone to (866) 440-9530
To prevent the spread of invasive mussels, be sure to clean, drain and dry your boats. Learn more at California State Parks’ Division of Boating and Waterways webpage: https://dbw.parks.ca.gov/StopQZ.
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