20 DECEMBER • WORLD AQUACULTURE • WWW.WAS.ORG Pearl culture in India has historically focused on offshore rearing techniques, particularly in ecologically sensitive marine zones such as the Andaman and Nicobar Islands. Among the most valued species is Pinctada margaritifera, renowned for producing high-quality black pearls. Traditional offshore culture systems typically involve suspending pearl oysters beneath floating rafts in protected lagoon environments, where natural parameters such as temperature, salinity, and food availability generally favor growth and biomineralization. In early 2024, an integrated research initiative was launched to augment these efforts by introducing onshore pearl culture systems aimed at enhancing biological performance, environmental control, and operational sustainability. This shift was motivated by limitations increasingly observed in offshore systems — including predation, biofouling, stormrelated risks, and labor-intensive maintenance — that constrained scalability and introduced ecological stress to natural reef systems. The initial phase of the study was conducted at North Bay, South Andaman, a biologically rich coastal site characterized by abundant coral reefs and diverse marine fauna. Notably, P. margaritifera and Pteria penguin, which are usually found scattered in rocky crevices and reef fissures, were observed colonizing suspended rafts in high densities. This natural colonization facilitated a steady and sustainable supply of oysters for both experimental and commercial rearing. Preliminary offshore trials using 6 mm nuclei implants yielded nearly 1,000 pearls within six months, with minimal mortality and high retention rates. These encouraging outcomes validated the biological potential of local oyster stocks and set the stage for controlled onshore experimentation. Building on this foundation, larger oysters were subsequently selected for 10 mm nuclei implantation (Figure 1), extending the gestation period to approximately 15 months to maximize nacre deposition and pearl quality. The transition from opensea conditions to a closed, landbased culture model marked a critical innovation in this project. The onshore systems were designed to simulate nearnatural marine conditions while enabling precise regulation of temperature, water quality, nutrition, and surgical care. These advancements aimed to overcome offshore limitations and explore a sustainable path forward for decentralized, highefficiency pearl aquaculture adaptable to diverse geographies across India. Experimental Setup Controlled onshore pearl culture trials were conducted in the Andaman Islands in January 2024, focusing on two native marine pearl oyster species: Pinctada margaritifera and Pteria penguin. The study was designed to investigate the comparative efficacy of controlled versus semi-natural rearing environments on post-operative recovery and pearl formation. To achieve this, two distinct oyster batches - Batch 1 and Batch 2 - were established under different environmental management regimes. Both batches were reared and cared for in two identical conical fiberglass tanks, each with a capacity of 2,000 liters (Figure 2). These tanks were equipped to support the unique requirements of each experimental group. Batch 1 was housed in a fully controlled environment that incorporated a series of technological systems designed to maintain water quality and simulate stable marine conditions. A biological filtration unit, with a circulation capacity of 1,200 liters per hour, was installed to remove nitrogenous waste products such as ammonia and nitrites. This filtration system was vital in stabilizing water chemistry and supporting the metabolic needs of the oysters during their sensitive post-operative period. From Ocean to Land: Eco-Friendly Pearl Production through Onshore Marine Oyster Culture Ajai Kumar Sonkar FIGURE 1. In preliminary trials, oysters received 6 mm or 10 mm nuclei implants. FIGURE 2. Two identical fiberglass tanks were used, but with different environmental management regimes.
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