5/17/2023 0 Comments Oyster spat collectors![]() ![]() Third, blacklip pearl oysters from sheltered locations in the central- western Pacific have faster growth rates than those from eastern Polynesia Ž Friedman et al., 1996. Second, methods for collecting spat and growing blacklip pearl oysters are relatively simple. were exported annually from Solomon Islands until the end of 1993, when a moratorium on export of wild-caught pearl-shell was introduced Ž Richards et al., 1994. ![]() First, reasonable populations of blacklip pearl oysters still occur in some countries for example, about 25 tons Ž f 100,000 shells. Despite these differences, there are at least three reasons to explore the potential for culturing pearl oysters in the central-western Pacific. As a result of the more ‘open’ layout of reefs in the central-western Pacific, there are fewer obvious places where the spat of blacklip pearl oysters may accumulate. margaritifera, which are planktonic for ) 20 days Ž Southgate and Beer, 1996. , and there is no guarantee that larvae will be retained in the vicinity of natal reefs. Water movements are inherently less predictable Ž Andrews and Pickard, 1990. In general, reefs in the central-western Pacific have a more ‘open’ structure, with numerous passages linking patch, fringing and barrier reefs with deep-water. In the central-western Pacific, most reefs fringe high islands or occur in shallow, sub-littoral areas Ž Wells, 1988. However, there are major differences in the structure of reefs in the central-western Pacific compared to those in French Polynesia and Cook Islands Ž Wells, 1988. are particularly eager to assess their potential for farming black pearls. Several of the high-island nations of the central–western Pacific Ž Fiji, Vanuatu, Solomon Islands and Papua New Guinea. margaritifera is also distributed throughout much of the tropical Pacific Ž Sarver and Sims, 1996. Although the industry is confined mainly to lagoons in eastern Polynesia, P. The spat are then grown-out to a size suitable for the implantation of nuclei for the culture of pearls. of blacklip pearl oysters in such lagoons Ž Coeroli et al., 1984. ![]() ![]() Pearl oyster farmers in French Polynesia and Cook Islands capitalise on this situation by placing collectors for the spat Ž plantigrade larvae. When pearl oysters spawn within these habitats, the pelagic larvae are ‘trapped’ within the ‘enclosed’ lagoon Ž Richard, 1985. These atolls are favourable for the collection of juveniles because they have large lagoons, with limited exchange of water to the open ocean Ž Gabrie and Salvat, 1985. In French Polynesia and Cook Islands, a proportion of coral atolls are rich sources of juvenile P. and incur low transport costs Ž Sims, 1993. The national spat collection program will generate significant livelihood benefits across Fiji and support continued expansion of the Fijian cultured pearl industry. Results identified sites supporting high levels of pearl oyster recruitment as a basis for an ongoing national spat collection program, and support better targeting of spat collection activities that maximise oyster supply to the Fijian pearl industry. margaritifera based on greater levels of recruitment at these sites. penguin have greater tolerance of more turbid inshore sites than P. penguin ranged from 7.53 cm to 13.62 cm across sites. penguin were collected from all sites, with the highest number of recruits (495) recorded from Namarai (Viti Levu). margaritifera recruitment during the study and these were generally sites with relatively turbid water. margaritifera at any site was 8.61 ± 0.30 cm while the smallest was 4.26 ± 0.13 cm. The largest mean dorso-ventral measurement (DVM) of P. margaritifera juveniles were collected from all sites with the highest number of recruits (693) and the highest number of recruits per collector (2.10 ± 0.17) occurring at Nacobau (Vanua Levu). Spat collectors were deployed for a period of 10–15 months when the number of pearl oyster ( Pinctada margaritifera and Pteria penguin) spat attached to each collector was counted and shell size recorded. Spat collectors consisted of a 100 m longline from which 310 individual spat collectors were suspended. Twenty-nine sites across Fiji were used in this study. This supply can be inconsistent and a research program was implemented to determine recruitment of pearl oysters to spat collectors at sites throughout Fiji as a basis for developing a national spat collection program to improve reliability of oyster supply to the industry. Cultured pearl farming in Fiji relies on wild spat collection to supply the oysters used for pearl production. ![]()
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