Southeast and East Asia

Coral bleaching was first observed in Indonesia in January and February, 1998 as warm waters flowed through the Java Sea eastwards towards Lombok where bleaching was seen in March. During April and May, a warm pool of water developed during the northern summer around Cambodia, Thailand and parts of Sabah, Malaysia. Warm water bathed parts of the Philippines, Vietnam, Taiwan, and Japan in June and July, and also spread southwards towards Singapore and the Riau islands off Sumatra in June and July, before cooling in late July. Warm waters continued around Japan until August when the first typhoon in September cooled the waters.

Warm water temperatures in April 1998 caused widespread coral bleaching in the Gulf of Thailand from Narathivat province (South) and Trat province (far east), up to Chonburi province (the inner part of the Gulf). But there was no bleaching on the other side in the Andaman Sea. Water temperatures in the Gulf increased from the normal of 28-29oC to above 32oC, such that on Ko Samui it was 35oC. It was first noticed in the tourist centres of Chumpon and Surat Thani. Then bleaching spread north to reefs in the inner part of the Gulf (Koh Samet, off Samaesan) and off Pattaya. In some places, bleaching has affected 100% of Acropora, 80% of Pocillopora damicornis, and about 60 to 70% of massive Porites, especially in shallow water. Around Chumporn (Ko Kai, Ko Samet and Ko Tao – 10o50'N), 30-50 % of corals bleached. Around Sichang Island (inner part of the Gulf) and Mun Islands (Rayong), the impact was 50-60% of corals bleached, with mortality of about half. This is the first report of widespread bleaching in the Gulf of Thailand.(Tenshi Ayuki, Vipoosit Manthachitra, Suraphol Sudara)

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