See also: Seafood Safety; Food Safety Videos
Ciguatera poisoning is caused by consuming tropical marine fish which have accumulated a toxin which originates from certain species of algae (dinoflagellate). This algae is consumed by small fish, which in turn are eaten by larger fish, and so on up the food chain. The toxin generally accumulates in larger predator reef fish such as grouper, amberjack, sea bass, barracuda, snappers and Spanish mackerel. The toxin is tasteless, and is heat stable, so cooking does not destroy it.
The occurrence of toxic fish is sporadic and not all fish of a given species or from a given locality will be toxic. When cases are reported, or certain types of algae 'blooms' have occurred, warnings are generally issued to avoid eating large fish of the implicated species until testing shows the toxin no longer present.
Symptoms generally appear within 6 hours of eating the toxic fish, and include numbness and tingling, nausea, vomiting and diarrhea. Sensory reversal, feeling hot for cold and cold for hot may occur. There is no treatment, but symptoms generally subside in a few days. There have been some severe cases where the neurological symptoms have lasted for weeks and months. There have been some isolated cases which have persisted for years, and other cases where symptoms have recurred months or even years later. There is a low fatality rate.
Living in Key West, I avoid eating larger specimens of any of the implicated fish, especially when warnings are issued. For example, I only eat grouper under 5 pounds or so. They are not large enough to have accumulated much of the toxin, if it was present.