Intensive rearing of juvenile oysters Crassostrea gigas in an upwelling system: optimization of biological production Cédric Racher(') and Jcari-Picrrc Baud (2'

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Crassostrea gigas; Skeletonema costatum; cconomic cfficiency; multidimensional contin- gency table analysis; corrcspondence analysis; growth; nursery. Élevage intensif d'huîtres juvéniles Crassostrea gigas dans un système d'upwelling; optimisation de la
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.507.5062; http://archimer.ifremer.fr/doc/1992/publication-3061.pdf

Abstract Scasonal growth of juvenile oysters (Crussostreu gigus) kcpt in an intcnsive upwelling system was studied from 1984 to 1986 in 60 to 90-day growth cxpcrimcnts. Saline ground water was used to produce Skeletonema costatum which was injected as food into the water supplying the upwclling systcm. Oystcr dcnsity, water flow, phytoplankton concentration, tcmpcraturc and frequency of food addition were controlled. Oyster growth was analyscd with multidimensional contingency tables and correspondence analysis. The factors, in ordcr of dccreasing influence on growth, were temperaturc, food conccntration and oyster density. A rearing strategy was deduced from thc growth analysis for summer and winter. In summer, the density of 120,000 oystcrs/m2, the flow rate of 1 liter/d/oyster and the food conccntration of 0.5 10 " phytoplankton cells/litre gave the most interesting rcsults. Thc oystcrs grew from 0.014 g to 2.2 g after 60 days. In winter, thc hcat cxchangcr was necessary to increase the temperature from the 5°C naturally obscrvcd to thc 11°C required for valuable growth. Oyster density and food conccntration wcre the same as in summer. For a flow rate equal to 3 litcr/day/oystcr, oysters grew from 0.01 g to 0.5 g within 100 days. The cos1 and profit computations were derived from these strategies. It was concludcd that this typc of nursery would be profitable in spring, summer, and autumn but not in wintcr due to the high cost of heating the water.