Stimulating investment in pearl farming in ... - World Fish Center

Suitability of Habitats for Growth of Black-Lip and Silver-Lip Pearl Oysters Final, June 2008shallows, but has a silty bottom and a narrow silty beach in the north. There are tworelatively wide (450-550 m), deep (14 and 35 m) passes on the northern side, each of whichhas a patch reef at their entrance to the lagoon. There are also about 150 hoa (shallowchannels separating individual narrow islands on atoll reefs), some of which are open to thelagoon but blocked from the ocean, others are closed to the lagoon but open to the oceanwhile others are totally isolated. The water within the lagoon is similar to the ocean due tothe exchange that takes place through the passes and its large size. The reef flat has an algalridge approximately 10- 20 m wide. The submerged reef flat consists of a calcareousplatform studded with small colonies of coral. The abundance and diversity of corals issmall within the lagoon, but increases where the slope drops off. Patches of coral arerelatively abundant in the shallow areas in the southern part of the lagoon, where the wateris less silty, but abundance declines with depth. The pinnacles have a wide coral rockplatform on their sheltered sides, which is covered with sand, and scattered patches of coraland a sandy shelf with Acropora and encrusting algae on their exposed sides. The areaaround the base of the pinnacles is also sandy. A variety of scattered corals are found on theslope.Fakareva is a rectangular atoll. The lagoon is 56 km x 24 km, has islets at its eastern end andtwo passes. Takaroa atoll is 28 km x 8 km and has one pass into the lagoon.The volcanic islands Raiatea and Tahaa are surrounded by the same barrier reef. The lagoonis continuous except for two sections on the west coast. Mangareva is a high volcanic islandwith a 150 m wide fringing reef on the south coast, a 100-500 m wide, well-developed reef onthe east coast and reefs in shallow water on gentle slopes on the north and west sides,mainly around headlands.3.1.5 Solomon IslandsThe establishment of black pearl farms using wild spat and/or hatchery production hasbeen investigated (Friedman et al. 1996; Lane et al. 2003). A demonstration farm based onthe collection and rearing of wild spat has been established at Nusatupe, near Ghizo. Thissite is situated in the mid-lagoon and is subject to moderate near channel flows (Friedman etal. 1998). No information was found about water depth, temperature, salinity or foodsources at this location.3.1.6 VanuatuA black pearl culture feasibility study has been conducted at Peskarus in the MaskelynIslands, but trials were abandoned because there were insufficient stocks to support acommercial farm (SPC 2002). The potential for establishing black pearl farms has beeninvestigated (Lane et al. 2003).3.1.7 ConclusionsThe most productive black pearl farms are located in sheltered lagoons associated with atollsin French Polynesia and the Cook Islands, where this species reaches its greatest naturalabundance and wild spat for rearing are readily available. The feasibility of establishingfarms based on collection and rearing of wild stock/spat has also been investigated in othercoral reef habitats in Fiji, the Solomon Islands and Vanuatu. Several farms havesubsequently been established in Fiji. Commercial farm operations based on the supply ofjuvenile pearl oysters from hatcheries have also recently been established in WesternAustralia. Information is available about the environmental conditions in the vicinity ofsome of the farms in French Polynesia and the Cook Islands, but not those in Fiji andThe Ecology Lab Pty Ltd – Marine and Freshwater Studies Page 9