Integrating Coral Reef and Reef Fish Community Data to Support Sustainable Ecotourism Management in Lihaga Island, North Sulawesi, Indonesia

Coral reef ecosystems and reef-fish communities underpin essential ecosystem services in tropical seas, particularly for small-island ecotourism. Lihaga Island in North Sulawesi, Indonesia, is experiencing increasing ecological pressure as marine ecotourism expands, highlighting the need for integrated ecological assessments to support sustainable management. This study evaluates coral reef condition, reef-fish assemblages, and the presence of hawksbill turtles to assess their implications for sustainable ecotourism management. Field surveys were conducted from August to September 2023 at two marine stations surrounding the approximately 8-hectare island, quantifying live and dead coral cover, coral life-form composition, and reef-fish species richness and abundance using underwater visual census and benthic surveys, supported by multivariate analyses and spatial visualization. The coral reefs exhibited moderate overall condition, with mean live coral cover of 38.58 percent and dead coral cover of 40.32 percent. A total of 1,152 reef fishes representing 15 families and 72 species were recorded, dominated by Pomacentridae, Labridae, and Chaetodontidae. The presence of the Critically Endangered hawksbill turtle (Eretmochelys imbricata) indicated the persistence of functional nesting habitat. Sites with higher live coral cover supported greater reef-fish diversity, demonstrating strong ecological coupling between habitat complexity and community structure. The findings indicate that habitat degradation, shifts in trophic composition, and spatial overlap between tourism activities and turtle nesting zones pose risks to long-term ecosystem stability. Adaptive spatial zoning, visitor regulation, and ecologically informed governance are therefore essential to support sustainable small-island ecotourism at Lihaga Island.