Improvement of remote setting of the Pacific oyster (Crassostrea gigas) on French platic pipes

• Main Authors: Baud, Jean-pierre, Jolly, C., Bodoy, Alain
• Format: Conference Object
• Language: English
• Published: ICES-CIEM CM 1991 / K:29 Ref. F 1991
• Subjects: Plastic pipes; Crassostrea gigas; Oysters; Natural spatfall; Oysters culture; Collecteur; Huîtres; Captage naissain; Ostréiculture; Pacific oyster
• Online Access: https://archimer.ifremer.fr/doc/00000/3044/2629.pdf; https://archimer.ifremer.fr/doc/00000/3044/

The oysters culture in France is based on a natural spatfall, collected on cultches in setting areas. The collectors are then transfered on intertidal parcs for development during 1.5 to 3 years. The subsequent ongrowing stage is performed after separating the oysters and putting them in bags or by off-bottom cultivation. In order to improve the stock turnover and to improve the rearing conditions for the juveniles, experiments were performed to define optimal conditions for remote setting. After considering the previous studies a standard density of 2 000 larvae per cultch (plastic pipe) was selected. This corresponded to an average, theoretical density of 2.3 larvae.cm-2. The resulting density, at the end of the growing stage should average 25 kg of oysters (6 pipes) per metre of trestle. This was considered as equivalent to what was assessed on this area, for the end of the on-growing stage in bags. The spats usually aggregate themselves in a extremity of the cultch, which may results in poor growing conditions. Among the factors which act on this aggregation, two of them were considered on the present work. The first was the horizontal distribution of the cultches in two layers, inside the setting tank and the second one, concerned the timing for the distribution of the larvae into the tank (50 % the first day, and 50 % the second day, just after turning the pipes upside down). The parameters analysed were the setting ratio and the spatial distribution of the spats on the pipes (extremities, centre, upper and lower sides). Best results were obtained with horizontally disposed pipes, in two layers. Distributing separate amounts of larvae at 24 hours intervals and returning the cultch, improved the setting. L'ostréiculture française est basée traditionnellement sur le captage de naissains de gisements naturels. Les collecteurs sont ensuite transférés sur l'estran pour une durée d'élevage de 1,5 à 3 ans. La croissance finale s'effectue généralement après avoir séparé les huîtres de leur support dans des ...