INFLUENCE OF DENSITY AND DEPTH ON THE GROWTH OF JUVENILE SEA SCALLOPS (PLACOPECTEN-MAGELLANICUS) IN SUSPENDED CULTURE

We examined the influence of depth and stocking density on the growth and survival of juvenile sea scallops (Placopecten magellanicus) in suspended culture at Gascons, Baie des Chaleurs. An increase in density greatly reduced the growth of the shell, adductor muscle, and other tissues, possibly because of lower food availability and diminished space. Growth was also influenced by depth and was greater at 9 m than at 21 m. However, the effect of depth was largely masked by the effect of stocking density and fouling of pearl nets. The pattern of seasonal variations in growth varied with the parameter used to quantify growth, and the changes were correlated with temperature and with chlorophyll a in one size fraction (0.7-5 mu m) Survival was high at all depths and densities studied. Maximum growth was obtained at a density of 50 scallops.net(-1). However, the growth was only slightly reduced at 100 scallops.net(-1) and thus, this would be an ideal stocking density for growing scallops commercially if the objective is ear-hanging or bottom-seeding after 1 yr of suspended culture.