Ciguatera fish poisoning in humans is most commonly caused by eating carnivorous fish contaminated by a toxin produced by the dinoflagellate Gambierdiscus toxicus. The toxin bio-accumulates through the food chain, and carnivorous fish such as barracuda, red snappser, grouper, sturgeon, and amberjack are usually the most commonly involved.
In Canada, most cases of ciguatera poisoning reported in the past have involved Canadians who ate fish in the Caribbean while on holiday. These cases have implicated grouper in the Dominican Republic, kingfish in Jamaica, and barracuda in Haiti. A fish casserole caused the illness in 57 people during a trip to Cuba.
Ciguatera poisonings have also been reported as a result of importing certain fish. Dried barracuda brought back from Jamaica in 1983 and imported red snapper bought in an Ontario market were identified sources.