The coral reef health index in Teluk Sebong, Bintan Island

Abstract

Teluk Sebong is one of the areas around Bintan Island, Indonesia, that has potential coral reef resources. Bintan borders directly with neighbouring countries and with a major shipping lane (ALKI I) traversing the Indonesian Archipelago. This makes the coral reef ecosystems in this region particularly vulnerable to disruption from changes in the aquatic environment. There is a need for primary data on the coral reef ecosystem condition as a basis for understanding changes in this ecosystem. One commonly used method is the Coral Reef Health Index (CRHI), which can describe the current status in terms of live coral cover, the level of resilience (potential for recovery) during times of stress, the condition of economically important reef fish biomass, and ecologically related functions. The CRHI can be used in monitoring coral reef status and can provide a basis for the management of coral reef ecosystems. This study examined five sampling sites located in Teluk Sebong, Bintan Island. The in-situ data collection included the condition of coral reefs using the Underwater Photo Transect (UPT) method and reef fish condition using the Underwater Visual Census (UVC) method. The coral data collected were analyzed using the CPCe (Coral Point Calculate with Excel extension) software version 4.0 to determine the percentage benthic cover. The coral reef fish data were analyzed to provide target fish density and biomass values (carnivores and herbivores). The live coral cover in Teluk Sebong ranged from 30.87 - 45.40%. Out of the five research sites, Berakit, Pengudang, and Lagoi Bay had coral cover in the high category while coral cover at Banyan Tree and Rawa Island was in the medium category. Reef fish biomass in Teluk Sebong ranged from 9.26 - 108.07 kg/ha, and at all research sites fish biomass was in a low category. The coral reef ecosystem resilience in Teluk Sebong was high at the Berakit and Banyan tree sites; in contrast, Pengudang, Lagoi Bay, and Rawa Island were in the low resilience category. The coral reef index (CRHI) value was highest in Berakit (CRHI = 6), followed by Banyan Tree (CRHI = 5), Pengudang (CRHI = 4), Lagoi Bay (CRHI = 4), and Rawa Island (CRHI = 2).