Culture potential of the pearl oyster ( Pinctada imbricata) from the Caribbean. : II. Spat collection, and growth and mortality in culture systems

Abstract

Temporal variation in abundance of larvae and spat of the pearl oyster Pinctada imbricata was studied at several locations on the Colombian coast from May 1997 to June 1998. Larvae were sampled with bongo nets and spat were harvested from collectors at monthly intervals. Abundances of predators ( Cymatium gastropods, and portunid, xanthid and majiid crabs) were also recorded. A relationship between salinity, particulate organic matter and larvae abundance was observed, leading to peaks in abundance of spat on collectors some weeks later. Average catch rates of 10 spat collector −1 month −1, using collectors made of cheap easily accessible materials, indicate that availability of P. imbricata is sufficient to initiate and support aquaculture of this species. Growth and mortality rates of juveniles in three different culture systems at two densities (20% and 30%, i.e. percentage of available area covered by juveniles) showed that density within the same culture system had no effect on growth, but that growth differed significantly among the three culture systems. Growth in “bag” systems was lower than in boxes whereas growth in “suspended” and “bottom” boxes was similar and comparable to the growth of a natural population. The suspended boxes are the easiest to handle because they do not require SCUBA diving and so these systems are recommended.