THE ECOLOGICAL HEALTH OF CORAL REEFS IN THE WATERS OF ENGGANO ISLAND, THE OUTERMOST ISLAND IN THE EASTERN INDIAN OCEAN

Enggano waters are located in the outer waters of the eastern Indian Ocean which is thought to have a cluster of coral reefs that are important for marine ecosystems. Coral reef ecosystems have important benefits for marine and human life. The existence of coral reefs in the outer waters needs to be monitored so as not to exploit its natural resources. This study aims to monitor coral reef ecosystems through biological and physical-chemical approaches. Coral reef data collection using the Underwater Photo Transect (UPT) method was supported by 50 m transect lines and quadrant transects measuring 58 x 44cm. Underwater data recording used an Olympus Tough TG-6 digital camera. Physical-chemical data were taken in situ using portable devices and ex situ data in the form of nitrate and phosphate were analyzed in the laboratory. The results showed that the percentage of live coral cover ranged from 8.83% - 71.11%. Based on the results, 7 forms of coral reef growth were found and consisted of 14 coral reef genus. In general, the health level of coral reefs in Enggano Waters was in the medium category. Coral reef density ranged from 1.67 - 5.52colony/m2, diversity index was moderate, evenness index was high and dominance index was low. In general, physical-chemical parameters were at optimal values for coral reef life except salinity which was quite low. Salinity ranging from 14 - 19‰ was a parameter that was feared to be able to significantly affect the life, sustainability and balance of the coral reef ecosystem.