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Caulerpa Prolifera Invasion

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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

5 Ways that You Can Help Caulerpa Eradication


Donate to Eradication and Outreach Efforts

Eradication is a long and tedious process that will require significant funding to complete. Our team appreciates anything you can give!



Advocate for State Legislation

Call your state representatives and ask that they support a ban on the sale and transport of all Caulerpa species in California. As long as the plant is sold and transported along our coasts, there is always a chance of reintroduction and another long and costly eradication effort.

Keep Potential Invasives Out of our Waterways

Caulerpa prolifera was most likely introduced to Newport Bay via untreated aquarium water being dumped upstream. It is important that local aquarium owners are mindful of their impact on the environment and dispose of wastewater safely.

Spread the Word

Awareness is one of the best ways to fight both the current invasion and future Caulerpa introduction. If more people are aware of the issue, we will be better equipped to stop it.

Report Any Sightings

If you see a suspected Caulerpa plant in the wild, do not disturb it! Note down the time, location, number of plants, and surroundings and report the sighting to CDFW on their website. Caulerpa prolifera is a bright green plant. It has several small, flat blades that crinkle at the edges, connected by underground runners to roots in the substrate. It is commonly found in shallow, sandy areas, such as coves and lagoons.