WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2015 51 that are generally covered by pearly layers. Intricate aspects of the design are not visible but concentric thin microlayers were deposited over the Ganesha image and most aspects of the design were visible. The color of the upper portion of the pearl was golden and the lower was silvery-white. During implantation, a natural pearl with a diameter 6.3 mm and length of 15.2 mm long was encountered in the penguin’s wing oyster (Fig. 6). The natural pearl suggested the possibility of free nucleated pearls being cultured in this species. This natural pearl opened a new road of trials to introduce nuclei in new locations other than the gonad region. Several trials to introduce foreign bodies in different locations were carried out (Fig. 7). A breakthrough came when one showed success in producing free, 10 to 14-mm, nucleated pearls in the penguin’s wing oyster, which is usually not known as a species that produces nucleated cultured pearls. In this way, advanced technique to produce free nucleated pearls in the penguin’s wing oyster have been developed. Challenges The tsunami of 2004 destroyed the entire pearl culture facility, including sea-based floating installations situated at North Bay, South Andaman. Land at the project site sank more than one meter, reducing the intertidal area. Now the major portion of the area is underwater during low tide. There was a large shallow sea bottom area to place oyster cages but an unwelcome occurrence changed everything. The behavior of some fish species changed after the tsunami. Parrotfish Scarus ceruleus began preying on oysters. We did not immediately understand that they were preying on the oysters because they had always been there with the oysters below the floating rafts but had never harmed them. The tsunami destroyed corals and also buried them with sand brought up from the depths, causing a food constraint for parrotfish, inasmuch as they previously fed on algae attached to corals. As a consequence, parrotfish began preying on the available shellfish, such as pearl and rock oysters. The most productive harbor — North Bay — was no longer safe for oysters. From the initial stage, oysters were preyed upon by parrotfish. The crisis created an adverse situation for the project. We were compelled to find a way to protect the pearl oysters in the sea and to explore the possibility of rearing pearl oysters onshore FIGURE 5. The author with a Ganesha pearl. FIGURE 6. A natural pearl formed in a penguin’s wing oyster. FIGURE 7. The author implanting a nucleus into a pearl oyster. FIGURE 8. Cages for the protective rearing of pearl oysters. (CONTINUED ON PAGE 52)
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