0 Chinain, M Darius, T Ung, A. Tchou Fouc, M. Revel, T. Cruchet, P. Pauillac, S. Laurent, D. 2010 Toxicon In press 2010 <p>Based on epidemiological data available through long-term monitoring surveys conducted by both the Public Health Directorate and the Louis Malard</p> 0 Darius, T Ponton, D. Revel, T. Cruchet, P Ung, A. Tchou Fouc, M. Chinain, M 2007 Toxicon 50 5 612-26 2007 Ciguatera Fish Poisoning (CFP) is a tropical syndrome well known in remote archipelagos where the population is still dependent on fish resources. In order to assess the ciguatera risk in two islands of French Polynesia, Tubuai (Australes) and Nuku Hiva (Marquesas), a study was carried out on both Gambierdiscus populations as well as on various fish species using the receptor-binding assay (RBA) to detect and quantify ciguatoxins. Relationship between RBA data and size or weight of fish was evaluated, and when only few individuals for a particular species were available the trophic level was used to help comparisons between studied areas. According to epidemiological data, toxic versus safe areas were explored and compared in both islands. In Tubuai Island, Gambierdiscus cells were surprisingly absent in the north area, considered as a toxic area, but almost 94% of fishes were classified as RBA(+). In contrast, the south area, supposed to be safe, was evolving to be a risky area because of the presence of Gambierdiscus cells and 74% of fishes being RBA(+). In Nuku Hiva Island, Gambierdiscus cells were present in the toxic areas, Anaho, Taiohae and Taipivei, with two toxic blooms in Anaho Bay, but none in Terre Deserte, the fishing area of this island. With RBA data, fishes were analyzed to be RBA(+) at a high percentage in Anaho and Taiohae, higher than in Taipivei and Terre Deserte areas. In general, our findings were congruent with epidemiological data and the knowledge of local people only for risky fish species. 3 Chinain, M. Revel, T. Faust, M. A. Holmes, M. J. Ung, A. Pauillac, S. 2001 In : Harmful Algal Blooms, Hallegraeff G.M., Blackburn S.I., Bolch C.J. and Lewis R.J. , Eds). Intergovernmental Oceanographic Commission of UNESCO, pp 226-229 2001 The benthic dinoflagellate Gambierdiscus is regarded as the primary causative agent of Ciguatera Fish Poisoning, a disease prevalent in the Pacific regions, the Carribean and the Indian Ocean. Six distinct species within this genus, most of them being toxic, have been described so far on the basis of morphological criteria. The genetic characterization of various strains of G. toxicus has also been addressed in recent studies. In the present work, we investigated the usefulness of the rRNA genes for the molecular characterization and classification of Gambierdiscus isolated distributed in 5 of the 6 species described to date.Sequences of the 5.8S+ITS rDNA and the LSU rDNA D8-D10 regions of 11 Polynesian isolates were compared for phylogenetic analysis. Both regions proved to be useful biogeographical markers, as a grouping of these isolates according to their geographic origin (northern versus southern islands) was globally observed. To investigate the potential intesrest of the LSU rDNA D8-D10 regions in Gambierdiscus systematics, sequences of 8 isolates from distinct geographic origins distributed among 5 of the 6 morphospecies described to date, were also compared. Four molecular types corresponding to G. australes, G. polynesiensis, G. yasumotoi and G. toxicus/G. pacificus lineages could be distnguished. These results suggest that, within this genus, genetic data are fairly consistent with morphological classification by SEM microscopy. They also indicate that distinguishing species of Gambierdiscus can combine both molecular and traditional morphological criteria.