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

Water Temperature and Cyclone Frequency in the Pacific: Implications for Pearl Farming Final, June 2008cyclones. On the high islands of Fiji, Papua New Guinea, Solomon Islands and Vanuatu, themajor impacts are landslides on hills and deposition of sediment in valley bottoms resultingfrom heavy cyclonic rainfall.Tropical cyclones within the Australian region have caused the loss and stranding ofpearling boats, demolishment of pearling camps and numerous deaths. The accompanyingheavy rainfall, high winds and storm surges have also caused widespread movement ofpearl oysters and equipment on experimental lines and commercial oyster farms, damagedbenthic habitats, caused fluctuations in the availability of wild stock and reduced thelandings of the pearl oyster fishery in Exmouth Gulf. In 2000, damage to pearling facilitiesand loss of eight boats in the vicinity of Broome resulting from a tropical cyclone wasestimated to have cost the industry A$6 million. A tropical cyclone that hit the Cook Islandsin 1997caused the loss of harvested pearls and equipment, damaged above-waterinfrastructure and villages, resulted in the loss of 19 lives, but caused only limited damage tounderwater farming operations. The reduction in number and total area of pearl farms inManihiki Atoll that occurred between 1996 and 1999 has been linked with the impact of thiscyclone. In 1983, French Polynesia was hit by five cyclones; the attendant 4-5 m rise in sealevel and 8-10 m high waves destroyed boats, fishing equipment and pearl aquaculture raftsand submerged many villages on the atolls.General ConclusionsIn the South Pacific region, the identification of potential culture sites for black-lip andsilver-lip pearl oysters is hindered by the lack of information on latitudinal differences intheir optimum temperature ranges and the lack of easily-accessible information onprevailing sea temperatures. Whilst sea temperature and cyclone frequency are important,they are only two of a range of environmental factors that could influence production ofpearl oysters. The identification of potential culture sites should also be based on a soundknowledge of fluctuations in other environmental parameters, particularly food and siltlevels, plus an appreciation of the vulnerability of different areas to earthquakes, tsunamis,sea-level rise, volcanic eruptions and large-scale pollution events. As a number of variablesoperating over spatial scales ranging from regional to site-specific determine the suitabilityof a location for pearl farming, it is impossible, given our current state of knowledge, to saywhether any one variable confers a significant advantage or disadvantage for a particularlocation.Due cconsideration should also be given to ways of avoiding or minimizing damage to pearlfarms. The development of better advance cyclone warning systems could enable farmers tomove longlines into deeper water and bring portable equipment ashore before weather andsea conditions deteriorate. It may also be possible to cyclone proof sub-surface farminfrastructure by using better attachments or “bunching up” longlines on the lagoon floor toreduce impacts from surges.The Ecology Lab Pty Ltd – Marine and Freshwater StudiesPage iv