Abstract
This paper documents the conditions of selected coral communities in the Gulf of Thailand with an insight into the degree of resistance and resilience to coral bleaching and localized anthropogenic disturbances. Live coral coverage at the study sites ranged from 5.2% at Koh Samui to 64.3% at Koh Lan. The most dominant coral species was Porites lutea. Only a few colonies of Acropora were found at the study sites. The most abundant macrobenthic animal was the sea urchin, Diadema setosum, with the highest population density 7.9 of individuals/m2 at Koh Khang Khao and D. setosum was not recorded in the belt transects at Koh Samui. Most coral colonies at Koh Lan showed partial mortality (77%), mainly pink spot and white band syndromes, and reflected potential impacts from coastal tourism. The highest recorded juvenile coral density was 8.3 colonies/m2 at Koh Kood while the lowest one was 1.1 colonies/m2 at Koh Khang Khao. The most abundant juvenile coral at all study sites was Porites spp. The occurrence of low live coral coverage and juvenile coral density in conjunction with high densities of the sea urchin D. setosum at Koh Khang Khao may partly explain why there are no structural reefs on the coasts of many islands in the inner part of the Gulf of Thailand. In addition, the present study documents macroalgae-dominated communities at Koh Samui and implies appropriate strategies and measures for coral reef restoration.
