Reproduction de l'huître creuse (Crassostra gigas) dans le Bassin de Marennes Oléron. La pêche expérimentale de larves d'huîtres, indicateurs de ponte et de recrutuement. Analyse spatio-temporelle et relation avec l'environnement

This study is based on catched larvae data base produced since C. gigas was first imported into the Charentais Sounds (late 1960s, early 1970s). The method for catching larvae using a towed net remained unchanged between 1950 and 1998. Four sites have been sampled in the Bay since 1970, two situated in the Seudre estuary and two in the middle of the Bay. Two other sites from near the mouth of the Charente River have been sampled since 1982. For each sample, oyster larvae were counted in four size classes, from the young larva (1-4 days) to near metamorphosis (16-20 days). Each year, 100 to 150 captures were carried out at all sample sites between June and September. Captures from July and August represent 99% of the total. The main variables were: capture frequency, start of the spawning season (PP), date of first spawning peak (DP), spawning index and recruitment index (IR)2. From a descriptive point of view, the spawning season may begin in late June or only during the first two weeks of August. It lasts 2 to 8 weeks with one to four major spawning peaks. Thus, the "classification" of the spawning season in C. gigas, as observed through larvae capture, shows high interannual variability....