Alimentation et déterminisme environnemental de la reproduction des huîtres perlières P. margaritifera sur l'atoll d'Ahe (Archipel des Tuamotu, Polynésie française)

While pearl culture industry represents one of the dominant business sector of French Polynesia, it still entirely relies on natural reproduction and spat collection. A better knowledge of reproduction determinism is thus of particular interest for the black lip pearl oyster P. margaritifera. This work is based (i) on in situ studies of the pearl oyster diet and of the environmental determinism of reproduction; and (ii) on the application to the black lip pearl oyster of a bio-energetic and deterministic model of growth and reproduction based on the Dynamic Energy Budget theory. In Ahe atoll lagoon, plankton concentration and composition fluctuations were strongly linked to wind regimes. These variations had a great impact on the diet of pearl oysters which was dominated by nanomicroplankton (especially nano-flagellates and dinoflagellates). Peaks of plankton concentration were associated with an increased gametogenesis rate and were shown to enhance spawning synchronisation in the population. Eventually, estimates of DEB parameters for P. margaritifera allowed us to correctly simulate its growth and reproduction and to clearly demonstrate the influence of plankton concentration on maturation and spawning synchronization of pearl oysters in atoll lagoons of French Polynesia. These results provide relevant features for a better understanding of spat collection variability in French Polynesian atoll lagoons. Moreover, the pearl oyster DEB model of adults growth and reproduction constitute a promising complementary tool for the comprehensive description of spat collection variability in atoll lagoons of French Polynesia.