STOCKING DENSITY EFFECTS ON LARVAL GROWTH AND SURVIVAL OF 2 CATARINA SCALLOP, ARGOPECTEN-VENTRICOSUS (EQUALS CIRCULARIS) (SOWERBY-II, 1842), POPULATIONS

Two populations of catarina scallop, Argopecten ventricosus (= circula ris) (Sowerby II, 1842), were evaluated for their larval growth and su rvival responses to different stocking densities, Larvae from the Magd alena population had a significantly higher growth but equal survival at a density of 10 larvae ml(-1) compared with 20 larvae ml(-1). Larva e from the Concepcion population grew better at densities of 15 and 20 larvae ml(-1) than at densities of 5 and 10 larvae ml(-1), although s urvival was lower at higher densities, The differing response of these two populations to increased stocking densities is explained as a pos sible consequence of different population adaptations related to behav ioural and physiological mechanisms, The importance of establishing op timum stocking densities for molluscan larvae is stressed in two conte xts: maximizing growth and survival for different populations when art ificially reared, and understanding the effects of stocking densities on phenotypic variance, especially during the course of genetic studie s.