Emmanuel Thouard

Recent improvements in broodstock management and larviculture in marine species in Polynesia and New Caledonia: genetic and health approaches

Abstract Aquaculture production in French Polynesia and New Caledonia relies upon domesticated broodstock of two introduced species (the shrimp Litopenaeus stylirostris , and the fish Lates calcarifer ) and on natural stock of the local pearl oyster Pinctada margaritifera . For L. stylirostris , refrigeration of shrimp sperm lowers the sanitary risk linked to the re-introduction of variability in Tahiti that is proved necessary by microsatellite markers. They also allow paternity controls that will improve future genetic management. Selective breeding programs for shrimp are underway in Tahiti and under assessment at pilot scale in New Caledonia. Conservation strategies are under elaboration for local populations of P. margaritifera that have been proven genetically differentiated. The recent development of pearl oyster hatcheries is the first step towards genetic improvement of this species. Thanks to geographical isolation and sanitary regulations, French Polynesia and New Caledonia are not affected by the viral outbreaks affecting shrimp elsewhere in the world (e.g., white spot and Taura syndrome viruses) and the pearl oyster in Japan (Akoya virus). Furthermore, a zoosanitary surveillance network of pearl oyster stocks is coming up in order to detect the emergence of any pathogen. Recently, alternative methods for antibiotherapy in shrimp larval rearing have been tested using probiotic bacteria, and could find an application in pearl oyster larval rearing.

Assessment of the contamination of marine fauna by chlordecone in Guadeloupe and Martinique (Lesser Antilles)

Chlordecone is an organochlorine pesticide, used in the Lesser Antilles from 1972 to 1993 to fight against a banana weevil. That molecule is very persistent in the natural environment and ends up in the sea with runoff waters. From 2003 to 2013, seven campaigns of samplings have been conducted to evaluate the level of contamination of fish, crustaceans, and mollusks. The present study is the first assessment and the first comparison of the concentrations of chlordecone between marine areas, taxonomic groups, and ecological factors like trophic groups or preferential habitat of fish species. The four most contaminated marine areas are located downstream the contaminated rivers and banana plantations. Crustaceans seemed to be more sensitive to the contamination than fish or mollusks. Finally, when comparing contamination of fish according to their ecology, we found that fish usually living at the border of mangrove and presenting detritivores-omnivores diets were the most contaminated by chlordecone. These results are particularly useful to protect the health of the local population by controlling the fishing and the commercialization of seafood products, potentially contaminated by chlordecone.

Spawning of yellowtail snapper (Ocyurus chrysurus Bloch 1791) in captivity

Abstract Observations on yellowtail snapper maturation indicated a long spawning season (March to October), including two periods of high sexual activity (March and July). Twenty-one batches of good quality eggs (mean viability rate 85%) were recorded without hormonal treatment. Spawning was also induced by HCG injection. Fecundity was high (172 000 eggs/kg), but the viability rate remained low (31%).

Selection of finfish species for aquaculture development in Martinique (F.W.I.)

Since 1981, in Martinique, a programme of selection of fishes suitable for aquaculture has been conducted. Zootechnical and socio-economical constraints have led to the choice of three species, endemic and exotic: the palometa (Trachinotus goodei ), the red drum (Sciaenops ocellata ) and the red florida hybrid (Oreochromis sp.).