Patch of invasive algae species discovered about 1.5 miles away from China Cove in Newport Harbor

A bed of Caulerpa prolifera that was removed from China Cove. Another small patch was discovered near Collins Island.
A bed of Caulerpa prolifera that was removed from China Cove. Another small patch was discovered near Collins Island.
(Courtesy of Merkel & Associates and Marine Taxonomic Services)

Another patch of Caulerpa prolifera was discovered in Newport Harbor late last month about 1.5 miles away from where the invasive algae species was initially discovered in China Cove.

The algae was initially discovered in Newport Harbor in March 2021 by a diver and was removed last summer. City officials confirmed in March this year, however, that though they felt they had “100% removal” that didn’t necessarily mean eradication.

Experts involved in the algae’s extraction confirmed there were traces of Caulerpa prolifera in the patches of eelgrass throughout the harbor. The discovery of this new patch of the invasive species confirms officials’ suspicions and concerns that the algae — which can recolonize through fragmentation, meaning the smallest pieces broken off the plant can become viable plants — may have spread further into Newport Harbor.

OC Coastkeeper marine restoration director Claire Arre said the patch was discovered near Collins Island, considered part of Balboa Island. While Arre was unable to confirm exact dimensions, she did say it was smaller than the patch found in China Cove.


“About 5.5 acres were surveyed around Collins Island … and this appears to be the only patch in the area, which is a good sign,” said Arre.

The nonprofit has partnered with the Southern California Caulerpa Action Team, which was initially established in 2000 for the removal of the Caulerpa taxifolia and disbanded in 2007.

The patch appears to have what Arre described as “rollers,” meaning there are fragments of the plants that are rolling with the waves but are otherwise unattached, along with what are established plants in the sediment. Removal efforts are slated to begin by early summer.

Arre said said the hope is to eventually be able to survey Balboa Island between China Cove and Collins Island for any other growths.

The plant is native to Florida and both tropical and subtropical locales. It is not known to be harmful to human beings but can have untold ramifications on the local ecosystem, officials said.

Support our coverage by becoming a digital subscriber.