About Caulerpa prolifera

Caulerpa prolifera is a fast-growing species of algae commonly sold in aquarium stores. It is native to the warm, tropical waters of Florida and in the Caribbean. C. prolifera is a particularly hardy strain, able to tolerate depths most other macroalgae cannot. In California, it is considered invasive as it can choke out native species of plants and seaweed and is inedible to most native fish.

An established patch of Caulerpa prolifera was identified in the China Cove area of Newport Bay in early 2021 by Coastkeeper divers, the first time this species has been identified in the waters of California. The Caulerpa genus is popular in the aquarium trade due to its hardy nature and fast growth rate, and was likely introduced to Newport Bay via improperly dumped aquarium water.

After the infestation was identified, removal efforts began quickly, but portions of the patch became fragmented and buried under the sand, making it more difficult than expected to remove completely. Orange County Coastkeeper partnered with the Southern California Caulerpa Action Team (SCCAT) to conduct surveys of the area to get a better idea of the extent of the problem. Currently, SCCAT has laid out a plan for removal dives, followed by several months of monitoring to ensure it does not return.

The process will likely be long, and funding is limited, making it difficult to take the necessary next steps for Caulerpa eradication.

The Caulerpa genus has been shown to rapidly outcompete native plants in areas where it is introduced, displacing wildlife and altering the ecosystem around it. A single blade can sprout a whole new plant, making it hard to remove without constant monitoring. It also contains toxins that repel most fish outside its native range. A close cousin of C. prolifera, Caulerpa taxifolia, was discovered in California in 2000 and took almost 7 years to eradicate. In that time, it did serious damage to native eelgrass habitats. While they have since recovered, this new species of Caulerpa is poised to do the same if it is not swiftly eradicated.

In 2001, the transportation and sale of Caulerpa taxifolia and several other Caulerpa species were banned in California. However, C. prolifera and the rest of the genus are still legal, increasing the risk of a new infestation.

Coastkeeper’s Goals

• Educate the public on the continued threat of the current Caulerpa prolifera invasion
• Get local aquarium dealers to stop Caulerpa sales
• Pass legislation to classify the entire Caulerpa genus as illegal to sell and transport in California so we can prevent this from happening again