EFFECTS OF DIFFERENT SUBSTRATA AND PROTECTIVE MESH BAGS ON COLLECTIONOF SPAT OF THE PEARL OYSTERS, PINCTADA-MARGARITIFERA (LINNAEUS, 1758)AND PINCTADA-MACULATA (GOULD, 1850)

Refining techniques for the collection of spat is important to the cul ture of blacklip pearl oysters, Pinctada margaritifera, especially whe re the collection of spat is marginally effective. We deployed 40 spat collectors at 15 sites within the open reef complexes of Solomon Isla nds to test the effects of different collectors (constructed of shadem esh and plastic sheeting) and protective mesh bags on the abundance of spat. After 6 mo, we recorded abundances of P. margaritifera, and ano ther pearl oyster, P. maculata, together with the numbers of predators associated with the collectors. Significantly more P. margaritifera w ere found on the shademesh, whereas live P. maculata were more abundan t on the plastic sheeting. Collectors inside protective mesh bags did not yield more pearl oysters than those left unprotected. Mesh bags tr apped predators such as Cymatium spp. gastropods and portunid crabs se ttling to the collectors from the plankton. The bags also fouled easil y, impeding waterflow to the collector. We conclude that experiments s hould be conducted to identify optimal materials for collecting the ta rget species of pearl oyster and that collectors should not be placed in protective mesh bags in environments similar to those of Solomon Is lands.