Postlarval survival and growth of Argopecten purpuratus (Lamarck, 1819) inBahia Inglesa, Chile: effects of origin, distribution in the bay and larval bacterioflora

Argopecten purpuratus is one of the most commercially important marine reso urces in Chile. One of the most critical steps in the massive culture of th is species is the transference of postlarvae from hatchery production to th e sea where significant mortality regularly occurs. The factors behind this low survival rate are probably diverse, and are as yet unknown. In the pre sent study, postlarval survival and growth was observed as a function of or igin of postlarvae, distribution of postlarvae in the bay, and microbial lo ading of the postlarvae. Survival rates were measured for different sites i n Bahia Inglesa, Chile (27 degrees 03' 24" S, 70 degrees 5 F 30" W) as well as changes in the bacterioflora of the postlarvae. Postlarvae utilized in the study were obtained from Cultivos Marinos Internacionales (III Region) and Cultivos Guayacan (IV Region). Results of the study clearly indicated t hat survival in culture of the postlarvae was related to their location in the bay and the origin of the postlarvae. However, the growth of the post-l arvae is not affected (P < 0.05). Microbiologically, it was observed that V ibrio spp. were the bacterial component most represented among strains isol ated from the postlarvae 53.36 %) from both populations studied. Principal component analysis revealed no differences between cultivable vibrios from both cultures. However, microflora from the Guayacan group were less suscep tible to increases in bacteria originating in their surrounding environment .