Red bass are a species notorious for causing ciguatera poisoning

Many anglers who visit tropical areas will have heard of ciguatera poison. These toxins are produced by dinoflagellates which adhere to coral and algae. They are eaten by small reef fish, which in turn are eaten by larger reef predators that accumulate the toxins in their bodies. Eating certain shallow-reef associated predatory fish – especially the larger ones – in some parts of the Pacific Islands and northern Australia can cause people to become very sick indeed. The species vary in different areas. Cooking does not destroy these toxins and they are resistant to gastric acid.

Symptoms can consist of moderate to severe diarrhoea, nausea, abdominal pain and vomiting. Neurological symptoms commonly include cold/hot sensitivity reversal, numbness around the lips and tongue and tingling in the limbs. In addition, muscle weakness, extreme fatigue, headaches, and dizziness are also reported. These can be onset between two and 48 hours after eating contaminated fish. Severe cases of ciguatera poisoning may result in shortness of breath, salivation, tearing, chills, rashes, itching, and paralysis.

There are about 50,000 reported ciguatera poisonings worldwide per year, but they rarely cause death (less than 0.5%). Ingesting alcohol, fish, nuts, and nut oils after exposure to ciguatera toxin may trigger recurrent symptoms. The symptoms can persist in varying severity for weeks to months after the acute illness.

Reef predators, including large trevally, red bass (red snapper), barracuda, tropical groupers and species like parrotfish, moray eels and coral trout are prime candidates to give ciguatera poisoning if eaten, with larger specimens being a greater risk, as they have built up higher levels of toxins.

Pelagic species, including yellowfin, mahimahi and wahoo are mostly fine to eat, and consequently these are the species usually served in restaurants. Dedicated deepwater dwellers (which stay below 200 or more metres) do not seem implicated in ciguatera poisoning; presumably because they are below the coral (and photosynthetic) zone. However, it pays to seek the advice of locals, especially any knowledgeable ex-pats, in any given area, before eating fish in the tropics.