[Heterogeneity of ciguatoxins extracted from fish caught in the French Antilles]. / Hétérogénéité des ciguatoxines extraites de poissons péchés aux Antilles françaises.

Ciguatoxin-like substances were extracted from the viscera or the flesh of eight Caribbean fish species, including small invertebrate feeders and large carnivores. The had similar properties, i.e. pharmacological action, solubility, chromatographic behaviour on silicic acid or Sephadex LH 20 column, stability in a weak acid solution and instability in alkaline medium. However, Florisil column and thin-layer chromatography showed different ciguatoxins whose number depended on tissue or species but not on fish trophic level. Less polar ciguatoxins appeared in salted and dried flesh. Thus, fish ciguatoxins are believed to be closely related substances, possibly changing in structure according to particular experimental conditions.

[Evaluation of different-stage levels of ciguatera toxicity of the marine food fish chain found around Saint Barthélemy Island in French Antilles]. / Evaluation des niveaux de toxicité ciguatérique des différents étages de la chaîne trophique pisciaire marine présente autour de l'île de Saint-Barthélemy aux Antilles Françaises.

A total of 259 specimens of 32 potentially ciguatoxic fish species from St-Barthelemy, Leeward Islands in the Caribbean sea were checked for ciguatoxin. It was found that flesh and viscera from 229 specimens belonging to 27 species (essentially bottom-dwelling species) were ciguatoxic. No correlation between toxicity and species size or diet was demonstrated since five of the six highly ciguatoxic species Seriola dumerili, Caranx latus, Caranx bartholomaei, Caranx ruber and Scomberomorus cavalla are large roving predators feeding mainly on fishes while the last species (Alphestes afer) is a benthic resident of very small size (less than 300 g) which feeds mainly on invertebrates. Small (less than 1 kg) benthic carnivorous fishes (invertebrate feeders), such as Bodianus rufus, Priacanthus arenatus, Mulloidichtys martinicus, Malacanthus plumieri and Halichoeres radiatus, are significantly ciguatoxic and play an important role in the transmission of ciguatoxin in the food chain. Other ciguatoxic species included large carnivorous fishes and the small surgeon Acanthurus bahianus. Furthermore, additional results suggest that most of edible benthic species from Saint-Barthelemy harbour ciguatoxin as well, though at an extremely low level. The ciguatera food chain in the Caribbean sea is therefore comparable with that described in the Pacific Ocean, except concerning small invertebrate feeders since their role in this chain is demonstrated for the first time.