The golden mussel, with a name that suggests it could be California’s bivalve mascot, is proving to be quite the menace as the state’s latest invasive species. This tiny freshwater mollusk has the potential to clog essential water supply pipes, marking it as a serious threat as it is identified in the region.
On October 17, sightings of these mollusks were confirmed at Rough and Ready Island, located near Stockton. They have since been reported in at least one additional area, O’Neill Forebay, in Merced County. The detection of the golden mussel in the Sacramento-San Joaquin Delta is noteworthy as it marks the first confirmed appearance of this species in North America, according to a state wildlife agency release.
Experts are concerned that this invasion could signal the onset of a prolonged battle to control its spread. Among the primary worries are the potential impacts on local ecosystems and the Delta’s pumping stations that deliver water to millions of residents and vast agricultural lands. UC Davis biologist Peter Moyle has stated the urgency of containment; if not managed quickly, the golden mussel may become impossible to eradicate. Moyle suggests that a focused eradication effort in the known affected areas may be an effective strategy, but if unsuccessful, the species could severely disrupt the food web by competing with native species for resources.
The California Department of Fish and Wildlife is actively evaluating the possible risks posed by the golden mussel. Officials have highlighted that this species poses a considerable immediate danger not only to the region’s ecological integrity but also to infrastructure and overall water quality.
In a preventive effort, the Department of Water Resources has begun vessel inspections to stymie the potential spread of these invasive mussels. This includes checking watercraft leaving O’Neill Forebay, San Luis Reservoir, and Los Banos Creek Reservoir to ensure that all water is drained from livewells and bilges. Tanya Veldhuizen, a project manager within the department, noted that increased vigilance is required to protect the State Water Project, which is critical for transporting water south from the Delta. Enhanced inspection routines and cleaning protocols are now in place to avert “mussel biofouling,” which could lead to significant operational challenges.
Originating from China and Southeast Asia, the golden mussel (scientifically known as Limnoperna fortunei) attaches itself to underwater surfaces, creating large clusters made of millions of individuals. These mussels feed by filtering water, profoundly changing the local nutrient dynamics by removing food resources vital for native species. Their aggressive spread in South America since the 1990s has resulted in significant environmental havoc, outcompeting indigenous mollusks and degrading ecosystems. They have been known to migrate as quickly as 150 miles per year, with many fearing they might penetrate biodiverse hotspots like the Amazon.
The pathways by which these mussels arrived in California remain uncertain, although it is speculated that they might have arrived via commercial shipping, similar to how they infiltrated South America. Many expected this occurrence; for instance, Moyle has anticipated the mussels’ arrival in California for years, given that the Delta has already been overrun by numerous invasive species, accounting for over 95% of its biomass.
Interestingly, the Delta has already experienced the introduction of other non-native aquatic species, including the Eurasian overbite clam. Such species have already contributed to the decline of local fish populations, as seen in the struggles of the Delta smelt, linked to these clams’ presence.
While many are concerned about the implications of the golden mussel’s spread, there’s a contrasting opinion from local residents like Brett Baker, a water attorney and long-time resident of Sutter Island. He expresses skepticism about the golden mussel’s potential for causing long-lasting damage, suggesting that the Delta’s ecological niches may already be filled and may not allow new invasive species to thrive. Baker, having witnessed numerous invasive species concerns throughout his life, remains hopeful that the golden mussel will not cement itself into the Delta’s ecology for the long haul.
As California grapples with this latest invasive species, the full ramifications will unfold over time, and continued vigilance will be paramount in protecting the region’s delicate ecosystems and vital water supplies.