$1M+ allocated to tackle invasive seaweed species in Coronado Cays

There’s seaweed like eel grass that an ecosystem depends on, then there are other species that aren’t so welcome in San Diego Bay.

If you have your own saltwater aquarium at home, then you might be familiar with a seaweed that has made its way into San Diego Bay, despite it being illegal in California, according to the Port of San Diego. Not only is the seaweed invasive, but it’s costing local agencies thousands of dollars to remove.

“It’s a very bright fluorescent green algae. It looks very different from the drab olive green eel grass that you see in the bay naturally,” Dave Gibson, the executive officer with the San Diego Regional Water Quality Control Board, said.

It’s called Caulerpa prolifera. Despite its catchy green hues, Gibson says it’s invasive and a threat to the ecosystem.

”Caulerpa has a way of forcing out, basically out-competing eel grass and other forms of life in San Diego Bay that affect the fisheries,” Gibson said.

Teams of divers are always looking for this algae that doesn’t belong there, but it’s likely many have seen it elsewhere.

“These are commonly-sold aquarium plants algae,” Gibson said.

“In an aquarium it’s fine, it’s when people sometimes, unfortunately, dump their aquarium contents into the bay to free the fish, that they unfortunately free the Caulerpa,” Gibson said.

You can imagine the response when it was discovered during a dock project last year in Coronado Cays.

”Heartbreak and disappointment,” Gibson said.

Those emotions stem not just from the initial detection but to the future if this invasive species were to spread.

”Everything that the fish depend upon for habitat, breeding habitat for food we lose, and all the commercial benefits of having a healthy bay and healthy fishery are lost,” Gibson said.

To keep that from happening, U.S. Fish and Wildlife announced more funding Wednesday to keep the problem from getting worse.

”This is all a part of bipartisan infrastructure law, part of President Biden’s Investing in America agenda,” Matthew Strickler, the Deputy Assistant Secretary told the Department of the Interior, said. “We have $2 billion across the federal government, they’re investing in environmental restoration and environmental protection.”

Between the Port of San Diego, U.S. Fish and Wildlife, the Rapid Response for Aquatic Invasive Species, the State Water Resources Control Board, and the bipartisan infrastructure law, more than $1 million has been allocated to help resolve the issue.

”We’re deploying pieces of tarp and broad areas of tarp to control where we found it,” Gibson said.

Even if you can’t see it, the health of the ecosystem depends on stopping this threat.

”If we can get on top of these invasions quickly and make sure that we eradicate these small isolated patches of Caulerpa that we’ve seen here in the bay, that’s a huge win for us,” Strickler said.

Gibson says it will likely take several months to a couple of years to remove the invasive seaweed. The hope is that it doesn’t spread beyond Coronado Cays.

"The fear is that it’s already spread beyond the Coronado Cays area, it’s in the fish and wildlife refuge now, we’re trying to keep it out of the active part of the bay with props, and motors, and tides," Gibson said.

The Port of San Diego recommends the following when maintaining a saltwater aquarium:

• DO NOT use Caulerpa in your aquarium.
• DO NOT dump your aquariums into California waters or even pour the contents into streets or down storm drains that often discharge to the bay or ocean. ONLY drain aquariums into sinks or toilets as the water will circulate to a treatment plant that would help minimize the threat.
• DO NOT share or sell Caulerpa.