Popularity of reef fish spreads poisoning risk

ILOILO, Philippines

Bowls of piping-hot barracuda soup were the much-anticipated treat when the Roa family gathered for a casual and relaxing Sunday meal.

Within hours, all six felt deathly ill. So did two dozen others from the same neighborhood. Some complained of bodywide numbness. Others felt weakness in their legs. Several couldn’t speak or even open their mouths.

“I was scared. I really thought I was going to die,” said Dabby Roa, 21, a student who suffered numbness in his head, tingling in his hands and had trouble breathing. What Mr. Roa and the others suffered that night in August was ciguatera fish poisoning, a rarely fatal but growing menace from eating exotic fish. All had bought portions of the same barracuda from a vendor.

An estimated 50,000 people worldwide suffer ciguatera poisoning each year, though more than 90 percent of cases go unreported. Scientists say the risks are getting worse, because of damage that pollution and global warming inflict on the coral reefs where many fish species feed.

Dozens of popular fish types, including grouper and barracuda, live near reefs. They accumulate the toxic chemical in their bodies from eating smaller fish that graze on the poisonous algae. When oceans are warmed by the greenhouse effect and fouled by toxic runoff, coral reefs are damaged and poison algae thrives, the scientists say.

“Worldwide, we have a much bigger problem with toxins from algae in seafood than we had 20 or 30 years ago,” said Donald M. Anderson, director of the Coastal Ocean Institute at Woods Hole Oceanographic Institution in Massachusetts.

“We have more toxins, more species of algae producing the toxins and more areas affected around the world,” he said.

Homer cited ailment

Although risk of ciguatera poisoning has soared recently, the phenomenon is ancient. Fish poisoning shows up in Homer’s “Odyssey,” written some 800 years before the Christian era. Alexander the Great forbade his armies to eat fish for fear of being stricken, according to Yoshitsugi Hokama, a professor at the University of Hawaii.

Capt. James Cook and his crew probably suffered ciguatera poisoning in 1774 after eating fish near Vanuatu in the South Pacific, according to crew journals and correspondence studied by Dr. Michael Doherty of the Swedish Epilepsy Center in Seattle, writing in the scientific review Neurology.

Cook recorded that they “were seized with an extraordinary weakness in all our limbs attended with a numbness or sensation like … that … caused by exposing one’s hands or feet to a fire after having been pinched much by frost.”

Ciguatera has long been known in the South Pacific, the Caribbean and warmer areas of the Indian Ocean. Some South Pacific islanders use dogs to test fish before they eat.

But in the past decade, it has spread through Asia, Europe and the United States, where more restaurants are serving reef fish, prized for their fresh taste and relative rarity.

In the United States, ciguatera poisoning is most frequent in Florida, Texas and Hawaii, which has seen a fivefold increase since the 1970s to more than 250 cases per year.

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