Growth of blacklip pearl oyster ( Pinctada margaritifera) juveniles using different nursery culture techniques

Abstract

This study was based on blacklip pearl oyster ( Pinctada margaritifera) juveniles, that were hatchery-reared and 8 months old. They were held for 5 months in suspended culture using five culture techniques: in 24-pocket juvenile panel nets (PN24); enclosed within 5-mm plastic mesh ‘inserts’ placed in the pockets of eight-pocket adult panel nets (PN8); in 5-mm plastic mesh inserts without being placed into panel nets (INSERT); in plastic mesh trays (55×30×10 cm) with lids (TRAY); and by ‘ear’ hanging (EAR). Survival was high during the experiment and ranged from 100% in PN24 and PN8 to 90.6% for the INSERT treatment. Juveniles held in 24-pocket nets (PN24) and ear-hung juveniles showed the greatest growth during the experiment, and had significantly greater dorso-ventral height (DVH) and wet weight (WW) than oysters in all other treatments ( P <0.05). Pearl oysters held in inserts within adult panel nets (PN8) and alone (INSERT) showed the lowest mean DVH and WW. This probably resulted from heavy fouling by rock oysters associated with mesh inserts. When other factors such as cost, ease of construction and degree of fouling were considered with growth and survival, the five nursery methods were ranked in decreasing order as follows: PN24>EAR>TRAY>PN8>INSERT.