Stocking density effects on larval growth and survival of two catarina scallop, Argopecten ventricosus(= circularis) (Sowerby II, 1842), populations

Two populations of catarina scallop, Argopecten ventricosus (= circularis) (Sowerby II, 1842), were evaluated for their larval growth and survival responses to different stocking densities. Larvae from the Magdalena population had a significantly higher growth but equal survival at a density of 10 larvae ml−1 compared with 20 larvae ml−1. Larvae 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 survival was lower at higher densities. The differing response of these two populations to increased stocking densities is explained as a possible consequence of different population adaptations related to behavioural and physiological mechanisms. The importance of establishing optimum stocking densities for molluscan larvae is stressed in two contexts: maximizing growth and survival for different populations when artificially reared, and understanding the effects of stocking densities on phenotypic variance, especially during the course of genetic studies.