Effects of different feeding regimens on larval growth and the energy budget of juvenile Chilean scallops, Argopecten purpuratus Lamarck

Abstract

Effects of continuous and discontinuous feeding regimens on growth and survival of Argopecten purpuratus larvae and the partitioning of energy in juveniles are presented. Larvae from a single cohort were cultured under three feeding regimens: (1) fed once a day, (2) fed twice a day and (3) fed continuously, while keeping the total daily amount of food equal for each treatment. Larvae cultured under the continuous feeding regimen had faster growth and higher survival than those fed discontinuously. Early juveniles from a single cohort of larvae were cultured under the same conditions as larvae. Organic weight, energy content, filtration rate, oxygen consumption and excretion rate were measured after 16 days under these regimens. Maximal increase in shell length and in ash-free dry weight was attained by those juveniles fed continuously. No significant difference in energy content was found between the three groups of individuals. Juveniles fed continuously showed a higher metabolic rate than those fed once or twice a day. Ingestion rate and ammonia excretion did not differ significantly among individuals in the three feeding regimens. Results indicate there is better assimilation of food in both larvae and juveniles under a continuous feeding regimen.