Species and toxin variability in Gambierdiscus. Implications for CFP risk assessment and management.

Titre: 
Species and toxin variability in Gambierdiscus. Implications for CFP risk assessment and management.
Auteurs: 
Chinain M, Darius T, Litaker RW, Faust MA, Wang Z, Laurent D, Pauillac S
Type de communication: 
Communication orale
Conférence: 
Congrès Ciguatéra et Biotoxines associées (Nouméa, Nouvelle-Calédonie)
Année: 
10/2008

CFP risk assessment and management programs generally include the long-term monitoring of populations of Gambierdiscus, the primary causative agent of ciguatera, their toxicity and the resulting ciguatoxins flux through the upper food chain.

Regarding the surveillance of Gambierdiscus, three important issues need to be considered:
1/ the taxonomy in this genus, which needs to be clarified: up to now, 6 species of Gambierdiscus have been described, but recent data support the existence of potentially 4 new species (see Litaker et al., this workshop),
2/ the different sources of ciguatoxin variability in natural populations of this dinoflagellate, which explains in part why CFP events are spatially and temporally variable: the in vitro toxicity of several strains of G. toxicus, G. australes, G. pacificus and G. polynesiensis from various geographical origins is compared, and data on toxin production dynamics in a highly toxic clone of G. polynesiensis are also presented,
3/ the availability of detection methods and tools allowing to assess both the species composition and proportion of toxic strains within Gambierdiscus blooms: various methods are presented, with a tentative comparison of their advantages and limits.
The need for suitable real-time quantitative tools for the in situ detection of Gambierdiscus is discussed.

Workshop international Ciguatéra et biotoxines associées (Nouméa, 27-31 octobre 2008)