The Port of San Diego is keeping up its fight against an invasive algae spreading in San Diego Bay. The Port of San Diego received a $200,000 grant from the Pacific States Marine Fisheries Commission to support additional diver surveys and eradication efforts of an invasive algae known as Caulerp a in San Diego Bay, the Port of San Diego said in a news release. The Aquatic Invasive Species Rapid Response Fund, in cooperation with the U.S. Fish and Wildlife Service, provides grants to rapidly deploy measures for newly discovered invasive species found in freshwater and marine environments. In November 2023, the Port of San Diego adopted an emergency declaration after Caulerpa algae was discovered in the Coronado Cays. Since then, the board has approved 18 continuances of the local emergency, most recently extending through March 15, 2026. The algae are native to Florida and other subtropical and tropical locales, but can take over non-native natural habitats, disrupting the ecosystem and displacing native plants and the animals who rely on them. It spreads through “fragmentation driven primarily by tidal movement, vessel traffic and fishing activity,” according to a port statement. The port said the algae is not harmful to humans, but Caulerpa is putting state and federally protected native eelgrass habitats at risk in San Diego Bay. In late September 2023, divers found a small patch of the plant while conducting an in-water, pre-construction eelgrass/Caulerpa dive survey as a permit condition for a dock replacement project. Additional patches were discovered nearby during follow-up surveys. San Diego Bay May 16, 2024 Port fights invasive algae as another patch found in San Diego Bay Port of San Diego Nov 16, 2023 Fighting non-native seaweed in Coronado Cays costs Port of San Diego $92,000 In April and August 2025, divers found small Caulerpa patches in the San Diego Bay National Wildlife Refuge outside of and adjacent to the Cays. To date, nearly 11,300 square feet of seaweed have been discovered. Trained divers have covered all the patches with a sealed barrier to kill the algae by blocking it from light, oxygen and tidal circulation. It is illegal in California to possess, sell, or transport any Caulerpa seaweed. Caulerpa is used primarily in saltwater aquariums. Fines can range from $500 to $10,000 for each violation. According to the port, it is working closely with the Southern California Caulerpa Action Team, a coalition of state and federal agencies coordinating a rapid response to prevent further spread. As part of the eradication process, two years of monitoring with no new discoveries are required before the algae can be declared fully eradicated. More than $3.1 million has been committed to surveys and eradication, including $1,192,000 from port funds, $600,000 from state funds, and more than $1 million awarded to the San Diego Bay National Wildlife Refuge Complex from the Bipartisan Infrastructure Law, Inflation Reduction Act, and other federal sources. In California, workers have conducted routine monitoring of Caulerpa since the early 2000s. ...read more read less