The Sacramento-San Joaquin Delta in California has been invaded by a species of mussel never before seen in North America. The discovery is raising concerns about the ecological and infrastructure impacts the golden mussels (Limnoperna fortunei) may have in the Stockton and O’Neill Forebay areas. Native to China and Southeast Asia, these freshwater mussels are known for disrupting water systems and local ecosystems. Let’s take a look at the golden mussels, the threats they pose, and the recourses that governments, communities, and conservationists have.
Migrating from Asia to California
The golden mussels are believed to have arrived in California through ballast water discharged from international ships into San Francisco Bay and the Delta, which releases non-native aquatic species into new environments. Once introduced, these organisms can thrive in certain conditions, as seen in the area, and now without strict and regular “mussel biofouling” measures, such as cleaning and flushing, invasive species will continue finding their way into ecosystems unprepared for their impact.
Historically, mussels have clogged the intake pipes of an unwater supply system in urban Brazil by fixing themselves to underwater surfaces. They are also known to destroy underwater infrastructures, such as hydroelectric plants and water supply systems. They can spread up to 150 miles annually.
Meet the Golden Mussel
Golden mussels are small (half to two inches), freshwater mollusks native to Asia. They are golden or yellow in color, and their inner surface has a purple mother-of-pearl-like layer. They reproduce exceedingly fast by releasing larvae that spread quickly. Attaching themselves to surfaces such as natural rock and man-made structures, they create thick clusters known as “reefs” made from millions of animals. Despite filtering plankton (making the water cleaner), they also deplete nutrients in the water that other species depend on, disrupting the native food chain.
The Threat They Pose
The introduction of golden mussels into the Delta is concerning, particularly since it is already home to over 185 non-native plants and animals, making it fairly overwhelmed by invasive species as it is. Mussels tend to outcompete native organisms for food and habitat, leading to massive biodiversity loss, and habitat loss could lead to further biodiversity loss. They pose a particular threat to native endangered species, such as Longfin smelt, Chinook salmon, and native mussels.
Golden mussels over filter the water, reducing plankton populations and forcing native species to compete for food. This overly filtered water changes ecological dynamics and is likely to see more invasive plant growth in areas where mussels lodge themselves. It decreases nutrients, devastates native species, and constantly changes waterways as it spreads. The presence of golden mussels in the Delta ultimately means a decline in fish populations and the collapse of fragile food chains as the mussels begin to take over.
In addition to negatively affecting native ecosystems and species, mussels pose a significant threat to water infrastructure as they attach themselves to pipes, filters, and pumping stations, creating blockages that affect water flow and require expensive maintenance and repairs. This increased need for maintenance could result in an increase in community water rates, as the public pays for the mussels’ removal from their waterways.
Containing the Invasion
Biologists generally agree that early containment is critical in minimizing the golden mussel’s spread and impact on California’s waterways. Once established, invasive species like these are almost impossible to eliminate. Thus far, California has launched emergency measures to limit the spread of golden mussels through boat inspections, monitoring and maintenance of infrastructure, and the use of mechanical and chemical methods to remove mussels in some areas. These boat inspections aim to ensure vessels are free of larvae before entering new waterways, which means they have less chance of introducing the species to California’s waters. While these steps may slow the invasion, and early detection is of the utmost importance, complete eradication may be unattainable as the invasive species is so quick to spread.
Further, California’s communities are encouraged to take an active role in preventing the spread of these invasive mussels, and public awareness campaigns are underway to spread information on the invasive and destructive nature of the mussels. Boaters are encouraged to practice good cleanliness by thoroughly cleaning, draining, and drying their boats after each use. Even the simplest, smallest actions can make a significant difference in protecting the state’s waterways and residents’ cooperation is essential as officials work to limit the mussels’ invasion.
Conservation and the Way Forward
While the major concern is to control the spread of the invasive golden mussel, it can be argued that these efforts involve hard-to-swallow tactics, environmentally speaking. Chemical treatments, for example, are effective against the mussels, however, they pose risks to water quality and other aquatic ecosystems. Further, mechanical removal is labor-intensive and expensive. Therefore, it is up to officials to find a balance between ecological preservation and the maintenance of expansive and important water systems. On the other hand, an argument can be made that the costs of not removing the mussels from California’s waterways far outweigh those of proactive containment. Either way, California’s response to this invasion will likely set a precedent for managing future threats.
The presence of the golden mussel in California highlights the ongoing struggle to safeguard ecosystems and infrastructure from invasive species. While current efforts are focused on containment, long-term solutions include ongoing public awareness, stricter enforcement of shipping regulations, and innovations in biological control methods. With sufficient data on past invasions, California can learn how to better reduce future threats. As the state tackles this challenge, the future of the Delta—and those ecosystems, communities, and industries that rely on it—will depend on continuous preventative measures and collaboration.
