Status of Coral Reef Communities on Two Carbonate Platforms (Tun Sakaran Marine Park, East Sabah, Malaysia)

This study concerns three sites, located on carbonate platforms, east Sabah: Gaya West, Gaya East, and Mantabuan. At each site, the dominant coral shapes and their health were recorded (lagoons and outer slopes). Densities of echinoderms, Tridacna, and nudibranchs were recorded while fish density was estimated. Generally, the coral vitality is low (≤50% living corals). Massive corals dominate all sites, except the Gaya West-outer slope where coral coverage and diversity are the highest. On the Mantabuan-mesh reef, a diverse Acropora assemblage dominates the landscape. On the reef flat of Gaya East, monospecific circa 10 meter coral patches occur. Primary producers are scarce on all sites. Sea urchins, dominated by Diadema, are abundant on the Gaya East-reef flat and the Gaya West-mesh reef. Sea stars and holothurids are the most prevalent in Gaya West-outer slope, although they remain scarce. Crinoids are only abundant in Mantabuan. Stegastes damselfish highly characterizes the sites of Gaya East (reef flat and inner slope) and the Mantabuan-mesh reef. On the Mantabuan-outer slope, parrotfish and other fishes are plentiful. No sign of eutrophication has been detected and natural hypersedimentation and/or eventual ancient bleaching events appear to be the direct principal causes of coral death or coral degradation. 1. Introduction An exceptionally high biodiversity prompted the creation of the Tun Sakaran Marine Park (TSMP) in the western part of the Celebes Sea, east of Semporna, Sabah, Malaysia, as the site supports a greater diversity of marine species than recorded elsewhere in Malaysia. The site is therefore of regional, national, and local importance. Marine and coastal habitats include (1) mangroves, (2) seagrass beds, (3) lagoons, (4) fringing, patch and bank reefs and (5) open water. Studies show that the diversity of marine species in the proposed park is very high. There are over 600 species of fish and at least 250 species of corals [1, 2]. Harborne et al. [3], summarizing fragmented studies of coral species’ richness around Malaysia, reported a total of 323 species. Around the reefs, 265 species of molluscs occur [4], and there may be as many as 140 species of sponges, 70 species of soft corals, and at least 50 species of gorgonians [5, 6]. In addition, a high diversity of echinoderms exists, with a total of 109 species recorded [5, 7, 8]. Several of the sponges and soft corals found in the Gaya lagoon are new undescribed species. One sponge is very unusual and possibly endemic to the Semporna reefs [9]. Also, Allen [1] found two new species