Improved ocean-based nursery culture of blacklip pearl oyster (Pinctada margaritifera) juveniles in mesh baskets using cyanoacrylate adhesive

Abstract

The blacklip pearl oyster, Pinctada margaritifera, supports well-established cultured pearl industries throughout the Pacific with various nursery culture methods used to on-grow juvenile oysters to a size suitable for pearl production. Locally-available plastic baskets are commonly used to rear juvenile oysters, but they do not prevent oysters from aggregating, which negatively impacts production. To develop an understanding of how basket-based nursery culture might best be adapted for rearing juvenile P. margaritifera, this study examined growth and survival of juveniles of varying sizes and stocked at varying densities in mesh baskets when using a cyanoacrylate adhesive to prevent aggregation. During a 3.5-month ocean-based nursery culture period, stocking density was shown to have a significant effect on growth (F = 11.53, p < 0.001), yet a minimal influence on oyster survival (χ2 = 5.05, p = 0.28). By contrast, stocking size influenced survival (χ2 = 7.17, p = 0.03), but had minimal impact on growth (F = 3.24, p = 0.08). Given that mean ( ± SD) survival of juveniles ranged from 65.0 ± 14.4% to 94.0 ± 8.2% and dorsoventral shell growth ranged from 13.9 ± 6.2 mm to 19.7 ± 6.3 mm, depending on stocking density and stocking size, these factors clearly merit consideration before fixing juvenile oysters to baskets with an adhesive. Such results broaden our knowledge of nursery culture methods for P. margaritifera and improve options for small-scale pearl farmers in the Pacific.