GROWTH AND SURVIVAL OF JUVENILES OF Argopecten purpuratus IN BOTTOM AND SUSPENDED CULTURES IN CASMA, PERU

This study analyzes and compares the growth and survival of juvenile Argopecten purpuratus cultivated in suspended and bottom systems in Casma, Ancash-Peru. From July 29th to October 21th, 2006 an experiment was installed using pearl nets and yards with individuals of 10mm (0.067g of soft tissue) at densities of 816, 2450, and 4080 indiv/m(2). Every two weeks individuals were measured (mm, shell height) and weighted (g, total and tissue weight) and dead scallops counted. Additionally information on production costs was recorded in order to compare profits in both systems. At the end of the experiment height and weight were higher in suspended than in bottom system and showed an inverse relation with density. Growth rates in height and weight in suspended system ranged from 0.07 to 0.43 mm/day and from 0.009 and 0.100 g/day and in bottom system varied between 0.11 and 0.26 mm/day and between 0.007 and 0.045 g/day, respectively. Survival was higher in suspended (96.8%) than in bottom systems (84.8%). The ANOVA showed a significant effect of density and culture system on growth and survival of juvenile scallops (P<0.01). The cost-benefit analysis demonstrated that scallop culture in bottom systems is more profitable than in suspended systems. Maximum profit is reached in bottom systems at a density of 4080 ind/m(2) and at 816 ind/m(2) in suspended systems. The feasibility of the adoption of bottom systems for culture of juveniles by enterprises and fisherman is discussed.