PATTERNS OF RUGOSITY ON CORAL REEFS AROUND LAE-LAE, SAMALONA, BARRANG LOMPO AND KAPOPOSANG ISLANDS

Abstract

Corals have many growth forms, creating many nooks and crannies which provide specialized places for marine organisms to shelter, live, and breed. Reef rugosity is a simple surface roughness measurement; a high rugosity value will support fish communities. This research measured the differences in reef rugosities in four islands in Spermonde Archipelago, Indonesia based on their distance from the mainland and the reef depth. Observation sites were Lae-Lae (LL; inshore zone), Samalona and Barrang Lompo (SA and BL; inner mid-shelf zone), and Kapoposang (KP; outer zone). At each station, rugosity was measured on the reef slope in two depth zones: 3-5 m shallow and 6-10 m deep using chains. The rugosity index at shallow reefs was increasing towards outer zones (Lae-Lae: 0.143 ± 0.015; Kapoposang: 0.655 ± 0.133), which means shallow reefs further from the Sulawesi mainland have more complex structures. There are differences between sites (P-value: 0.0000641) namely LL-BL sites (0.0001675), SA-BL (0.0001873), LL-KP (0.0016070), and SA-KP (0.0018514). At deeper depths, the rugosity was varied with Kapoposang having a higher value (0.451 ± 0.207). The inshore-offshore rugosity patterns in the four sampled islands are likely linked to anthropogenic pressures from the mainland of Sulawesi.