Winged oyster pearl industry development in Tonga

• Ministry of Fisheries, Tonga
• Secretariat of the Pacific Community, New Caledonia

The winged pearl oyster, Pteria penguin, is traditionally used for production of half-pearls ('mabe') in Tonga for which there is an export market in Japan and elsewhere. Pteria penguin was introduced to Tonga in 1975 by the Tasaki Pearl Co. of Japan. Subsequent research conducted by the Ministry of Fisheries in Tonga and supported by FAO SPADP attracted the interest of local investors and there were 25 small pearl farms in Tonga at the end of 2000. The current value of the industry is not known as the majority of pearls are sold locally.

A major impediment to the sustainability and expansion of the pearl industry in Tonga is a reliable and adequate supply of oysters. Over recent years, poor recruitment of spat has resulted in the harvesting of adult oysters from the wild, which has further impacted recruitment, and natural spat fall of Pteria penguin in Vava'u is now extremely limited. This project will focus on the developing of appropriate hatchery culture techniques for Pteria penguin and the use of hatchery-propagated oysters for pearl production.

Further development of the pearl industry in Tonga is hindered by a lack of knowledge of the culture requirements of Pteria penguin. Research is required to optimise culture methodology and pearl production as a basis for sustainable industry development. This project will address the following major aspects:
Hatchery culture of Pteria penguin and optimisation of hatchery culture techniques
Nursery culture and grow-out; optimising culture techniques
Half-pearl production and aspects effecting pearl quality (position, location, time)
Investigation of round pearl production from Pteria penguin
Training of Tonga Fisheries staff in culture methods and pearl production
Training of farmers and members of the PGA.