Tropical toxin may be moving north into the Gulf of Mexico
Have a fondness for tropical reef fish for dinner? Beware of Ciguatera fish poisoning (CFP), say National Science Foundation-funded scientists.
CFP is caused by the consumption of seafood, primarily reef fish, contaminated with ciguatoxins. When people eat these fish, they’re exposed to the toxins. CFP can lead to nausea and pain, as well as cardiac and neurological symptoms. It affects tens of thousands of people globally each year, with annual costs of $30 million in the U.S. alone.
“The toxins are most often found in large reef fish such as barracuda, grouper, red snapper, eel, amberjack, sea bass and Spanish mackerel,” said Michael Parsons of Florida Gulf Coast University. “Imported fish served in restaurants may contain the toxins, and produce illness that goes undiagnosed by physicians who aren’t familiar with the symptoms of a tropical toxin.”
Gambiertoxins, precursors of ciguatoxins produced by the subtropical dinoflagellate Gambierdiscus, enter food webs when reef fish consume this dinoflagellate. These precursors are transferred to higher trophic levels until they reach fish species in commercial and recreational fisheries. “Currently, there is no practical means to screen fish to determine whether they contain the toxins, so people consume fish that are prone to CFP at their own risk,” Parsons reported at the recent Ocean Sciences Meeting in San Diego, California.
To study the effects of such ocean pathogens, NSF and the National Institute of Environmental Health Sciences, one of the National Institutes of Health, funded the CFP center.
“To guard against potential health threats, the links between oceans and human health need to be better understood,” said Hedy Edmonds, a program director in NSF’s Division of Ocean Sciences. “This center brings together scientists doing basic research on the oceans with those in biology and human health to study processes that affect thousands of people.”
CFP outbreaks have been linked to warming water temperatures and coral reef degradation, and are expected to increase in coming years. Although CFP is endemic to the Caribbean, the Florida Keys and South Florida, it appears to be expanding northward into the Gulf of Mexico. Toxin-carrying fish were recently identified off the Texas-Louisiana coast.
The Ciguatera center is supporting several research projects, among them: examining the role climate change may play in the expansion of CFP into temperate waters; obtaining a better understanding of the toxic metabolites produced by certain Gambierdiscus strains and the transfer of these compounds into coastal and coral reef food webs; and studying the toxin’s effects on cellular metabolism. “The goals,” said Parsons, “are to predict when and where ciguatera outbreaks are likely to occur, develop effective screening methods to protect people from consuming contaminated fish, and better treat people afflicted with this fish poisoning.”
For now, he said, “your best bet is to steer clear of fish known to cause CFP.”