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

Water Temperature and Cyclone Frequency in the Pacific: Implications for Pearl Farming Final, June 2008This in-situ logger network has subsequently been expanded by the Fijian branch of theGlobal Coral Reef Monitoring Network (Sykes 2007). By December 2006, sea temperaturewas being monitored in nine regions (Coral Coast, Savusavu, Suva, Somosomo Straits, EastTavenui, Yasawa Island, Namena, Kadavu and Vatu-i-Ra). An additional logger wasinstalled in Beqa Lagoon, near Storm Island in January 2007. Data from January 1997 toNovember 2007 were obtained from a logger facing the ocean at a depth of 5-7 m on MountMutiny, a pinnacle, in Vatu-i-Ra Passage (Figure 4). During this period the temperaturevaried from approximately 24.0 °C (September/October 1997) to just over 30 °C (February2002). It is also evident that the minimum water temperature in 1997 was well below thatexperienced in any of the other years and that the minimum temperatures in 1998, 2002-2005were below those in 1999-2001 and 2006-2007. An analysis carried out on data from January1999 to May 2006 indicated that the number of days per year with temperatures in excess of29 °C varied from < 20 in 1999 and 2003 to > 80 in 2000 and 2002 (Sykes 2007).Temperature data from the loggers deployed at Yasawa Island, Vatu-i-Ra, Kadavu and SuvaHarbour over the period September 2006 to October 2007 have also been compared (Figure5) (Helen Sykes pers. comm.). The overall trend was similar across the four locations,however, peak temperatures were clearly maintained over a longer period (January to April)at Yasawa and Vatu-i-Ra than at Suva and Yasawa Island (February to April). Thetemperature at Yasawa Island was generally greater while that at Kadavu was smaller thanat the other locations. From December to April, temperatures in excess of 29 °C wererelatively common at Yasawa Island, but of rare occurrence at the other locations.The SEAFRAME gauge installed at Lautoka on the western side of Viti Levu in October 1992indicates that sea temperatures since then have varied from a minimum of 24.2 °C in August1993 to a maximum of 32.5 °C in April 2006 (Bureau of Meteorology, Australia 2006b).2.3.3.4 French PolynesiaIn French Polynesia, the sea temperature varies from 20-22 °C in winter and from 26-30 °C insummer (Wells and Jenkins 1988). In this region, sea temperatures decrease southward andeastward to Rapa, where the minimum temperature suitable for growth of coral is found. Inthe Gambier Archipelago, the sea temperature varies from about 22 °C in August to 26 °C inMarch.2.3.3.5 Papua New GuineaA water temperature probe deployed on the eastern side of Lion Island in Bootless Bay,Papua New Guinea between August 1998 and February 2000 indicated that watertemperature ranged from 25.55 °C (September 1999) to 30.85 °C (February 2000) (Quinn andKojis 2000). Sea temperatures recorded during a rapid assessment of marine biodiversity inMilne Bay Province ranged from approximately 26 °C to 30 °C, with the northern section ofMilne Bay experiencing warmer temperatures (28-30 °C) than the southern section (26-28 °C)(Allen et al. 2003). The highest temperatures were recorded at Fergusson Island, AmphlettsGroup, and Cape Vogel and the lowest temperatures in the western part of the CalvadosChain.The SEAFRAME gauge installed at Lombrum on Manus Island in September 1994 indicatesthat sea temperatures since then have varied from a minimum of 27.8 °C in September 1997and April 1998 to a maximum of 32.6 °C in November 2000 (Bureau of Meteorology,Australia 2006c). The SEAFRAME records also show that mean water temperatures offManus Island were about 2 °C below normal during the 1997/1998 El Niño.The Ecology Lab Pty Ltd – Marine and Freshwater Studies Page 7