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

Water Temperature and Cyclone Frequency in the Pacific: Implications for Pearl Farming Final, June 2008these waters. On the basis of our current knowledge, it is not possible to say whether the seatemperature regime in Solomon Islands would be more advantageous for pearl farming thanthat in the other South Pacific nations considered.4.2 Risk of Damage to Pearl Farms from Tropical CyclonesAs the South Pacific region (east of 160°) usually experiences fewer tropical cyclones thanthe Australian region, the risk of damage to pearl farms and associated infrastructure is alsolikely to be smaller. The risk of cyclone damage also differs across the South Pacific region,being 60%, 50%, 30%, 15% and 10% for Vanuatu, Fiji, southern Cook Islands, FrenchPolynesia and the Solomon Islands, respectively (NIWA 1997). It is, however, important tonote that in a widespread nation, such as French Polynesia, the risk of cyclones varies acrossthe archipelagos and that the risk of cyclones within the Australian/South-West PacificBasin also depends on the ENSO phenomenon. For example, during El Niño years, the riskof cyclones in the Southern Cook Islands and French Polynesia increases to 75% and 50%,respectively, remains at 50% in Fiji, but decreases to 40% in Vanuatu and 10% in theSolomon Islands. The risk of tropical cyclones also declines in the Australian region(Nicholls 1984).If the strength or frequency of El Niño events increases, as is predicted with global warming,the easterly shift in tropical cyclone activity in the South Pacific region is likely to becomethe norm rather than an occasional event. Tropical cyclones are also expected to persist forlonger and travel further south before they lose energy and decay. The low-lying nature ofmany of the islands in the Cook Islands and French Polynesia means that they arevulnerable not only to overtopping by storm surges and extreme wave action generated bycyclones, but also to sea-level rise associated with global warming. The pearl farmindustries in the Cook Islands and French Polynesia are both known to have been adverselyimpacted by cyclones in recent decades (Ponia et al. 2000; UNESCAP 2000). In the future,they are likely to be impacted not only by cyclone activity, but also by sea-level rise.Although impacts from cyclones are periodic, it may be wise to establish new pearl farms innations, where the risk of damage from natural disasters and climate change is smaller.Whilst cyclones are less frequent in Solomon Islands than in most pearl farming areas, it isnot possible, on the basis of our current knowledge, to determine whether pearl farmingwould be more advantageous there than in other South Pacific nations.Due consideration should also be given to ways of avoiding or minimizing damage to pearlfarms. The development of better advance cyclone warning systems, for example, couldenable farmers to move longlines into deeper water and bring portable equipment ashorebefore weather and sea conditions deteriorate. It may also be possible to cyclone proof subsurfacefarm infrastructure by using better attachments or “bunching up” longlines on thelagoon floor to reduce impacts from surges.4.3 Overall ConclusionsIn the South Pacific region, the identification of potential culture sites for black-lip andsilver-pearl pearl oysters is currently hindered by the lack of information on latitudinaldifferences in their optimal temperature ranges and the general lack of easily-accessibleinformation on prevailing sea temperatures. Whilst sea temperature and cyclone frequencyare important, they are only two of a range of environmental factors that could influenceproduction of pearl oysters. The identification of potential culture sites should also be basedon a sound knowledge of fluctuations in a number of other environmental parameters,The Ecology Lab Pty Ltd – Marine and Freshwater Studies Page 17