Development of small scale village farms for blacklip pearl oysters in the Solomon Islands using wild spat

• Ministry of Agriculture and Fisheries, Solomon Islands
• James Cook University, Australia
• James Cook University, Australia

The purpose of this project is to assess the potential for developing village-based industries for culture of pearl oysters in the Solomon Islands. This application seeks to build on the results of the initial SPG FIS/93/720. The objectives of phase 2 are 1) to work with local villages to scale up collection of blacklip pearl oyster spat at sites with the best collection in phase 1; 2) to continue experimentation to identify the optimum system for collecting spat of the blacklip pearl oyster; 3)to develop methods for maximising the survival of oysters in the juvenile grow-out phase; 4) to assist villagers to establish small-scale pearl farms based on oysters derived from wild spat; and 4) to collect information on rates of spat collection, the cost of collecting spat, mortality of juveniles etc., that is needed to produce an economic analysis of the likely returns to small scale village pearl farmers in the Solomon Islands.

The annual report was received on 29/11/96. During the first year it was confirmed that spat are likely to be abundant enough in the vicinity of Gizo and Noro to support village based farms for blacklip pearl oysters, and that the best collections are made during summer. Survival rate of spat on collectors was improved, and ways to reduce the cost of constructing the most effective type of spat collectors were identified. The research also yielded other important observations about the collection of spat: 1) Longlines at inshore sites produce good catches of spat prior to the wet season, but are not productive once there is heavy runoff. Conversely, longlines placed further from land at clearwater sites with moderate currents produce good numbers of spat throughout summer. 2) The longer collectors are left in the water after 3 months, the fewer live spat they produce. By comparison, spat removed from collectors at 3 months survive well in intermediate culture, provided fouling on grow-out systems is controlled and predators are removed regularly. Hypotheses stemming from these observations will be tested during the second year of Phase 2.