SEA SURFACE TEMPERATURE RISING TREND AND ITS INFLUENCE ON THE CORAL MORTALITY IN PAGAI STRAIT, MENTAWAI ISLANDS, INDONESIA

Pagai Strait is threatened by warm water temperature. The Indian Ocean Dipole (IOD) is the major factor which influences the water temperature anomaly in the West Sumatera, which resulting in the high rate of coral mortality (bleaching). This study aimed to identify trends and changes in temperature anomalies that occurred during the last few years and their impact on coral bleaching in the Pagai Strait. The regional sea surface temperature (SST) was analyzed spatially and graphically, inverse distance weighted (IDW) is employed to process the spatial analysis of temperature data. The supporting coral's data is conducted by the previous research which employing the Line Intercept Transect (LIT) method, then calculate the percent cover and mortality index. The temperature trend is increased ± 3oC for 5 years due to the IOD event which occurring along the year, in 2016 the dipole mode condition was dominated by a negative value. It causes the high temperature in the western waters of Sumatera. The most pernicious impact is coral bleaching phenomenon, which is very alarming due to the low of percent cover and high mortality. It indicates that the water condition is not supporting the marine life.