Evaluation of culture enclosures for the mangrove oyster Crassostrea rhizophorae suspended from raft and long-line systems

Abstract

 We evaluated the growth and survival of the mangrove oyster Crassostrea rhizophorae (30 mm maximum length) reared in two suspended-culture systems (raft and long-line) using three types of enclosures (oyster enclosures, lantern nets and enclosures based on crates used to transport fish), at a density of 750 ind m^–2, in La Restinga Lagoon, Margarita Island, Venezuela, over the course of six months. No significant differences were found in shell growth (length and mass) due to the system and enclosures used; however, raft-cultured oysters showed better tissue growth. At the end of the study, the oysters in lantern nets suspended from rafts obtained a tissue mass that was around 40% higher than that of the rest of the oysters cultured in the other enclosures. Significant differences in oyster survival were not observed for the raft and long-line systems used, but the cumulative survival at the end of the study was significantly higher for the oyster enclosures (52–56%) than for the lantern nets (36–39%) and fish crates (24–25%). We therefore recommend employing rafts and discarding the use of crate-type enclosures in the culture of C. rhizophorae in lagoon systems.