Natural Perspectives

Vic Leipzig and Lou Murray

Getting sick of television’s “all Anthrax, all the time” coverage?

We’ve got something else for you to worry about.

We have a foreign menace invading us right here in Huntington Beach --

killer algae. Turn out the lights and settle down in front of the

fireplace to read this hometown horror story.

A tropical alga called Caulerpa taxifolia grows naturally in the

Caribbean, and is a popular saltwater aquarium plant. Unfortunately, it

has “escaped from captivity” and has shown up in bays and shallow lagoons

in other parts of the world, including here.

Caulerpa sends out as many as 200 feathery, fern-like fronds from its

base, forming a mat that is so dense that nothing else can survive. Local

marine life is effectively destroyed when Caulerpa invades a habitat.

Caulerpa was first spotted in the Mediterranean Sea near the French

Riviera in 1984. Within a few years it had covered over 10,000 acres.

Because Caulerpa became well established before its effects were

understood, efforts to eradicate it from the Mediterranean proved

fruitless and it continues its relentless progression.

Now we’re infested, too. Someone, probably an aquarium hobbyist,

accidentally introduced Caulerpa into Huntington Harbour. Colonies were

spotted in Seagate Lagoon, a three-acre impoundment connected to the

Harbour, in August, 2000.

Huntington Harbour is one of only two known sites along the entire

Pacific coast that Caulerpa has infested. The other colony is in Agua

Hedionda [Dirty Water] Lagoon in Carlsbad in San Diego County. The plants

in these two places are genetically identical to the Caulerpa that is

choking the Mediterranean Sea.

This invasive plant can clog boating channels and crowd out native

marine plants such as eelgrass with a beautiful but deadly forest of

greenery. Spiny lobsters, sea bass and flatfish such as halibut depend on

eelgrass beds for survival. Grebes dive there to find pipefish -- one of

their favorite foods. Dense blankets of Caulerpa rapidly overgrow

eelgrass beds, leaving the lobsters and fish with no place to live.

Why can’t animals simply adapt and eat Caulerpa? There’s a simple

answer. The alga has developed a defense mechanism in the form of a

toxin. While this toxin is harmless to humans, our local marine fish and

invertebrates wisely avoid it. Thus, with nothing here to eat it, the

plants can grow unchecked, crowding out the native plants that our local

marine wildlife depends upon.

According to Bob Hoffman, a biologist with Southern California’s

National Marine Fisheries Service who is involved in the Caulerpa removal

project, divers have attempted to eradicate Caulerpa from our local

waters. It is a particularly difficult task because the alga spreads from

broken fragments. If water containing even a tiny piece of alga is dumped

in the ocean or down a storm drain, the plant can become established.

It’s so hardy that it can survive for 10 days out of water. Even the

process of eradicating it can send fragments floating off to start new

colonies.

In 2000, divers dug some of the alga out. They covered larger infested

areas with underwater tarps and added chlorine-emitting devices to kill

the plants chemically. To see if the removal project was successful, they

marked spots where the algae had grown and checked periodically. They

killed the bulk of it, but some grew back.

The problem is so serious that federal and state agencies have funded

$700,000 for Orange County for Caulerpa removal and monitoring. During

the summer of 2001, divers killed new growth in both Huntington Harbour

and Agua Hedionda Lagoon. They also searched for Caulerpa in other areas,

including offshore, but fortunately found none.

Apparently the infestation in Huntington Harbour was caught in time to

avoid the horrendous problems this plant has caused in the Mediterranean.

Hoffman expects that all the algae will be destroyed by next summer.

However, some areas of the water are murky and it is possible that

colonies are lurking undetected and could spread from there. If you think

you see this fern-like alga, contact the Caulerpa Action Team via

e-mailat o7 [email protected] or by phoning (858) 467-2985.

This story has a happy ending. Future local releases of Caulerpa are

now far less likely, thanks to a bill sponsored by our district’s

Assemblyman Tom Harman and signed into law last week by Governor Gray

Davis. It is now illegal to import, sell or even own the banned algae in

California. It was already illegal to import the algae into the country

or sell it over the Internet because it was covered under the Federal

Noxious Weed Act of 1999.

If you have this awful alga in your home aquarium, get rid of it. Put

it in a plastic bag, freeze it solid to kill it and then either flush it

down the toilet (not the storm drain) or put it into the trash.

This attack of killer algae reminds us that the biggest threats to our

environment are likely to come not from foreign terrorists, but from our

own actions. We’re delighted that Harman took steps to stop this new

threat to our waters.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at o7 [email protected] .