WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2013 45 The black-lip pearl oyster (Fig. 1) is native to lagoons and shallow coastal waters (~1 to 40 meters) of the tropical Pacific Ocean (Carpenter et al. 1998, Wada 1991, Martin 2004). As adults, oysters attach by byssal threads to rocky habitat, primarily coral reefs. Fertilization is external and oysters begin life as a male; a few years later oysters become female, a process dependent on environmental conditions and food resources (Ellis and Haws 1999, Haws 2002). The lifespan of black-lip pearl oysters can reach 60 years if environmental conditions are favorable (Martin 2004). Pearls are produced when there is a foreign object inside the oyster, causing the oyster to secrete an iridescent liquid that forms around and conceals the particle. Over time, this foreign object evolves into a pearl. Only one oyster in 2000 produces pearls in a natural setting. However, with trained and skilled technicians, 800 marketable pearls can be produced from 1000 oysters (Ellis and Haws 1999). The production of pearls has evolved over many years with newer technologies to enhance production (Kurihara et al. 2012). There were once vast natural populations of black-lip pearl oysters; now there is only a small fraction of wild populations remaining (Sims1992). Environmental conditions have deteriorated and, along with pollution, have affected growth and development of the black-lip pearl oysters (Ellis and Haws 1999, McGladdery 2007). Pearl Mariculture in the Marshall Islands The Republic of the Marshall Islands (RMI) is located in the Western Indo-Pacific geographic region. Population growth and reduction of the importance of copra (dried coconut kernels from which oil is extracted) as the primary source of income has The Black-Lip Pearl Oyster Hatchery at the College of the Marshall Islands Gulnihal Ozbay, Anthony Jackson and Tabwi Aini resulted in a declining standard of living over the past 20 years. In the climate of this area, cultured black-lip pearl oysters can grow, mature and maintain sexual reproductive functions actively year-round (Le Moullac et al. 2011). Mariculture of black-lip pearl oysters has good income earning potential (MIMRA 2005) and has been one of the most important and sustainable commercial aquafarming activities in the RMI (Figs. 2 and 3; Haws and Ellis 2000, CTSA 2003, Chutaro 2007). Income generated by blacklip pearl oyster farming can provide economic opportunities that may arrest the current trend of outer islanders gravitating to the capital seeking work (Dybdahl et al. 2005). The pearl industry in Micronesia is in its infancy and there are pressing needs for research on quality improvement of cultured black-lip pearl oysters (Ito 2007, McGladdery et al. 2007). Activities of the College of the Marshall Islands’ Black Pearl Research Program The College of the Marshall Islands’ Black Pearl Research Program started large-scale hatchery production in 2003 and produced 1.07 million black-lip pearl oyster spat for distribution to two local companies (CTSA 2003). This was the first time in more than two years that spat had been produced and distributed to RMI farms. The former Black Pearls of Micronesia hatchery at Woja experienced mass mortality of larvae in 2002, making the College hatchery the only spat provider in the islands. In 2003, there were two local pearl oyster aquaculture companies (MIMRA 2005). In 2009, there was no commercial pearl aquaculture industry remaining because of a lack of a reliable supply of spat from hatcheries and available spat in (CONTINUED ON PAGE 46) FIGURE 1. Black-lip pearl oyster. FIGURE 2. To prevent potential loss of rejected pearl nuclei, seeded pearl oysters are sewn into fine-mesh bags
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