Port of San Diego Receives Grant to Fight Invasive Seaweed

The $200,000 grant will fund additional diver surveys and eradication efforts of Caulerpa algae in San Diego Bay.

Jan. 28, 2026 at 6:47pm

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The Port of San Diego has received a $200,000 grant from the Pacific States Marine Fisheries Commission to continue its fight against the invasive Caulerpa algae spreading in the San Diego Bay. The port has been working to eradicate the seaweed, which can disrupt the local ecosystem, since it was first discovered in the Coronado Cays in 2023.

Why it matters

The Caulerpa algae is an invasive species that can take over natural habitats and displace native plants and animals. Protecting the San Diego Bay's ecosystem, which includes state and federally protected eelgrass habitats, is crucial for the local marine environment and wildlife.

The details

Since the initial discovery in 2023, divers have found nearly 11,300 square feet of Caulerpa seaweed in the San Diego Bay. The port has been covering the patches with sealed barriers to kill the algae by blocking it from light, oxygen, and tidal circulation. Over $3.1 million has been committed to surveys and eradication efforts, including funding from the port, the state, and federal sources.

  • In November 2023, the Port of San Diego adopted an emergency declaration after Caulerpa algae was discovered in the Coronado Cays.
  • In late September 2023, divers found the first small patch of Caulerpa during a pre-construction survey.
  • In April and August 2025, divers found additional small Caulerpa patches in the San Diego Bay National Wildlife Refuge.

The players

Port of San Diego

The government agency responsible for managing the San Diego Bay and overseeing the eradication efforts of the invasive Caulerpa algae.

Pacific States Marine Fisheries Commission

The organization that provided the $200,000 grant to the Port of San Diego to support the Caulerpa eradication efforts.

Caulerpa

The invasive algae species that has been spreading in the San Diego Bay, disrupting the local ecosystem and threatening native eelgrass habitats.

Southern California Caulerpa Action Team

A coalition of state and federal agencies coordinating the rapid response to prevent the further spread of Caulerpa in California.

San Diego Bay National Wildlife Refuge Complex

The federal wildlife refuge that has received over $1 million in funding from the Bipartisan Infrastructure Law and other sources to support the Caulerpa eradication efforts.

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What’s next

The port must continue its monitoring efforts for two years with no new Caulerpa discoveries before the algae can be declared fully eradicated from the San Diego Bay.

The takeaway

The Port of San Diego's ongoing efforts to eradicate the invasive Caulerpa algae demonstrate the importance of proactive measures to protect local ecosystems from non-native species that can disrupt the natural balance and threaten sensitive habitats.