that doesn’t mean they’re
focus on research
“More and more reef
currently producing tox-
in. “No one really knows
what turns on a ciguatera
fishes are being event,” he says. As part
Clockwise from top: of a study funded by the
A barracuda hunts around
exported...and
National Oceanic and At-
an oil platform in the Gulf mospheric Association’s
of Mexico, photo by Tracy ECOHAB program, Villa-
Villareal; the dinoflagellate they’re exporting real is growing G. toxicus
Gambierdiscus toxicus, in his Port Aransas lab to
photo by Maria Faust;
the toxin, too.”
determine what environ-
Dr. Tracy Villareal, mental conditions might
photo by Matt Lankes. cause them to produce
toxin.
Ciguatoxin turns up in fish on our dinner plates because it passes
Toxic Seafood
up the food chain from the dinoflagellates to the fish that we like to
eat. Fish like barracuda, snapper and grouper accumulate the toxin
The hunt for ciguatera is on in the Gulf of Mexico
much the same as mercury or DDT. These fish, and the fishers who
seek them out, are drawn to the artificial reefs growing on the oil
arine scientist Dr. Tracy Villareal has platforms.
discovered that oil platforms peppering To find out if fish from around these platforms are harboring the
the Texas Gulf coast could be acting as toxin, Villareal collected barracuda brought in by fishers competing
the perfect incubator for ciguatera, the in the Summer 2005 MSI Barracuda Hunt. He and his collaborators
most common form of seafood poison- are analyzing a heap of barracuda—a total of 169 fish weighing-in at
ing in the world. 1.2 metric tons—for the presence of the toxin. “The initial results show
Ciguatera affects up to 500,000 that we can measure ciguatoxin in some of these fish,” says Villareal.
people every year worldwide, but cases Regardless of the direct threat to Texas fishers, Villareal says that
are still rare in Texas and the United ciguatera could become more of a problem throughout the United
States, says Villareal, associate professor at the Marine Science Insti- States. “More and more reef fishes are being exported to the higher
tute (MSI). The illness, found primarily in the tropics, causes nausea, latitudes and they’re exporting the toxin, too,” he says. “It’s a real
vomiting, teeth pain, numbness, prickliness, and a reversal of hot and interesting problem that the developing world is exporting to the
cold sensations. Occasionally, ciguatera is fatal. developed world.” ✥
People get ciguatera after eating fish loaded with a toxin produced
by a tiny, one-celled dinoflagellate called Gambierdiscus toxicus. The
soft and muddy bottoms of the Texas coast are not good habitat for
Got Ciguatera?
G. toxicus, which likes to grow on hard surfaces in warm waters. “But
when you get an oil platform sticking-up into the clear blue water, If you’ve ever become sick from eating fish caught offshore in Texas,
you get corals growing on them,” explains Villareal. “The coral is call 1-888-474-5929 or e-mail ciguatera@cdc.gov.
an indicator of the type of water conditions and habitat G. toxicus The following fish, if caught in tropical hotspots for ciguatera, should
prefers. It’s enough of a coral community that the ciguatera dinofla- be eaten with caution: barracuda, greater amberjack, king mackerel,
gellates are there.” black grouper and blackfin snapper.
Villareal found the dinoflagelletes growing on one hundred percent For more information on ciguatera and a complete list of affected fish,
of the Gulf oil platforms he sampled in summer 2005, but he says visit www.cdc.gov/nceh/ciguatera.
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