2001–2002 - California Sea Grant - UC San Diego

potential for the plant to spread uncontrollably, California Sea Grant and
other state and federal agencies quickly organized to make sure that what
happened in Europe would not repeat itself in the United States. Although
Caulerpa has not yet been totally eradicated, there is hope that it
will be. As of mid-2002, the biomass of the Caulerpa infestation in
Carlsbad had been reduced by about 90 percent.
In collaboration with other agencies, Sea Grant provided support for
three key projects designed to help agencies eradicate
existing infestations and prevent new ones. The projects
were also tailored to complement a larger, multi-agency
Caulerpa eradication effort led by the Southern California
Caulerpa Action Team (SCCAT) and the biological
consulting firm, Merkel and Associates. The California
Regional Water Quality Control Board, the National
Marine Fisheries Service and the California Department
of Fish and Game are members of SCCAT.
A point of pride for Sea Grant is the rapidity with
which we were able to respond to the discovery of
Caulerpa. Through our Rapid Response program, which
provides a mechanism for dealing with urgent, marine-
A close-up of Caulerpa growing among eel grass shoots in Agua
Hedionda Lagoon in Carlsbad, California. Photo: City of Carlsbad
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related issues, Sea Grant scientists were able to initiate their projects soon
after Caulerpa was identified. Such prompt attention is not common
within the structure of most marine-science funding programs. As the
situation in Europe has painfully shown, hesitancy from Sea Grant, or any
other institution, could have been disastrous. Of particular concern is the
possibility for the seaweed to spread to the open coast, where containment
would become costly and technically very difficult.
To evaluate areas vulnerable to
future infestations, Sea Grant
funded Dr. Susan Williams, director
of the Bodega Marine Laboratory of
University of California at Davis, to
map out the potential geographic
range of Caulerpa based on available
light, salinity and coastal ocean
water temperatures. Her research
looked at how far and how fast
Caulerpa could potentially spread,
and she identified waterways that
share the characteristics most
favorable to the introduction,
proliferation and spread of
Caulerpa. Her work suggests that
all lagoons in Southern California are at potential risk, as well as colder
waters in Oregon and even Washington. Mexico is also at potential risk.
Originally a tropical seaweed, Caulerpa, Williams reported, has become
tolerant to colder coastal climates. San Francisco Bay is at high risk, she
added, because it is a destination for “live rock” shipped overseas for the
aquarium trade. Live rock is typically a piece of live coral covered with
other living marine organisms. Caulerpa fragments have been found on
live rock imports.
In the second Sea Grant project, biologist Dr. Steven Murray of California
State University, Fullerton, and Sea Grant Trainee Susan Frisch
documented the commercial availability of Caulerpa at retail aquarium
stores in Southern California. Of the 50 stores visited for their survey, 52
percent sold specimens of the genus Caulerpa. Ten percent sold the
invasive strain of C. taxifolia. About 95 percent sold live rock. Since their
“We said early on, we were not going to
duplicate the mistakes of the past. The
reason we have been so successful is that
all the groups involved have worked
collaboratively, that includes Sea Grant.”
—BOB HOFFMAN, Southern California
environmental coordinator for the Southwest
Regional Office of the National
Marine Fisheries Service, the lead federal
agency in the Caulerpa eradication effort.