Document Type : Original Article
Authors
1
Master’s Program in Marine Science, Postgraduate School, Universitas Negeri Gorontalo
2
Department of Marine Science, Faculty of Marine and Fisheries Technology, Universitas Negeri Gorontalo
3
Department of Fishery Products Technology, Faculty of Marine and Fisheries Technology, Universitas Negeri Gorontalo
4
Indonesian Marine Science Graduates Association-ISKINDO, Gorontalo, Indonesia
5
Marine and Coastal Resource Management Agency of Makassar, Ministry of Marine Affairs and Fisheries, Indonesia
Abstract
Soft corals, particularly Isis hippuris, play an essential role in reef ecosystems, yet their population dynamics remain poorly studied in Gorontalo Waters, Indonesia. This study assessed the abundance, density, size-class structure, and environmental drivers of I. hippuris across reef slope and reef flat habitats in Boalemo during July–August 2025. Data were collected from belt transects deployed at six stations, complemented by in situ water-quality measurements. Results revealed pronounced spatial heterogeneity: reef flats supported higher colony densities (0.03–0.38 colonies/m², total maximum 190 colonies) than reef slopes (0.018–0.278 colonies/m², total maximum 139 colonies). Size-frequency distributions were dominated by small colonies (< 30cm), whereas larger colonies (> 50cm) were rare, indicating active recruitment but limited survival or growth into larger size classes. Among the environmental variables measured, statistical analysis using the Spearman rank correlation identified temperature as the most influential factor, showing a significant negative correlation with colony density (ρ= -0.899, P< 0.05). Pulau Bitila consistently exhibited high densities and functions as an ecological hotspot, whereas Batu Keramat exhibited the lowest densities, suggesting local vulnerability. Comparisons with Indo-Pacific studies confirm that Boalemo densities lie within global ranges (0.1–5.0 colonies/m²) but below peaks were reported elsewhere (e.g., Makassar Strait). These findings underscore the ecological importance of I. hippuris and support targeted conservation measures, including marine protected area zoning and adaptive management. The study provides a robust baseline for future work on demographic trends, genetic connectivity, and responses to anthropogenic stressors.
Keywords
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