The use of high resolution satellite imagery to identify coral reef cover and its correlation with the abundance of reef fish in Nias Island, North Sumatera, Indonesia

Indonesia is located in the Southeast Asia region, which is famous for its coral biodiversity. It formed the well-known Coral Triangle Initiative with other six countries in the region. Coral reefs, as the most fertile and diverse ecosystem, with massive biogenic structure, are prone and vulnerable to several stressors and changes. Fishery resources, especially reef fish, are associated with coral reefs, with a significant correlation with coral reef communities. The study was conducted in Soma Islands, Nias District, and used the remote sensing technique in maximizing Pleiades satellite images combined with the Lyzenga algorithm and in situ observation. The Diversity Index, Uniformity Index, and Dominance Index were used to identify coral reefs in Soma Islands. Coral reefs were dominated by fringing reefs, where the coverage of the live coral in the islands was categorized as very good, ranging from 67.8 to 92.28%. The total extent of live coral reefs observed from satellite images was 5.8 ha or almost 47% from the total seafloor substrate. There was a positive correlation between live coral reefs and reef fish abundance, with 676 individuals 250 m-2 in Soma Sebua Island, 595 individuals 250 m-2 in Soma Sideide Islands, and 1107 individuals 250 m-2 in Soma Shoal