Source and Spread

Source and Spread: Genetic evidence indicates that most likely the source of the infestation in areas where Caulerpa taxifolia is not native is through the release from aquaria. Once introduced, Caulerpa taxifolia spreads by fragmentation, and even a small, broken off fragment can form a new plant. Distances between colonies can be great due to transport on boat anchors and fishing gear. Caulerpa taxifolia does not float, has never been observed to grow on boat hulls, and is unlikely to be transported in ballast water.  Sexual reproduction has not been observed in the aquarium strain of Caulerpa taxifolia.

Mediterranean infestation: The aquarium strain of Caulerpa taxifolia was first found in the Mediterranean Sea off Monaco, adjacent to the Oceanographic Museum of Monaco around 1984.  Since then, Caulerpa taxifolia has spread along the Mediterranean coast and dramatically altered and displace native plant and animal communities. Early eradication was not attempted in the Mediterranean, and the infestation is now considered beyond control. As of 2001, it was estimated the Caulerpa taxifolia has infested over 30,000 acres of seafloor in Spain, France, Italy, Croatia, and Tunisia. Caulerpa taxifolia infestations negatively impacted tourism,commercial and recreational fishing, and recreational activities such as SCUBA diving.

Australia infestation:  The  invasive aquarium strain of Caulerpa taxifolia has been reported in South Australia ands New South Wales and is invading in a pattern similar to the Mediterranean infestation. Efforts are being made to control its spread.

Southern California infestation : Caulerpa taxifolia was first identified in June 2000 in Agua Hedionda Lagoon, a coastal marine lagoon located in Carlsbad in San Diego County. Its growth pattern was similar to that observed in the Mediterranean Sea, having spread to many areas  and displaced the native seagrass. In July 2000, another infestation was reported in a portion of Huntington Harbor in Orange County. Test results indicate that the Caulerpa taxifolia in both areas is genetically identical to the aquarium strain. Releases from aquaria, either directly into the water body, or indirectly through a storm drain, are most likely sources of both Southern California infestations.

Protect our Waters

Aquarium water and other contents should never be emptied into or near any gutter, storm creek, lagoon, bay harbor or the ocean. Aquarium water should be disposed of only in a sink or toilet.  Rock and other solid material from an aquarium should be disposed of in a trash can. Caulerpa taxifolia from an aquarium (and anything it is attached to), should be placed in a plastic bag, put in a freezer for at least 24 hours, and then disposed of in a trash can. If any seaweed suspected to be Caulerpa taxifolia is found on fishing gear, anchoring gear, or vessels, it should be removed, carefully bagged(since even the smallest fragment has the potential to regenerate into a new plant) and reported.  In order to prevent new infestations and comply with the law, Caulerpa taxifolia should not be purchased sold or distributed.

Any sightings should be immediately reported to the California Department of Fish & Wildlife at 858.467.4218 (wpaznokas@dfg.ca.gov) or NOAA Fisheries at 562.980.4037 (Bryant.chesney@noaa.gov)