Aquatic Macrobenthic Diversity in Simlong, Batangay City
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| Aquatic Macrobenthic Diversity in Simlong, Batangay City
Objectives This study generally aims to assess the current status of coral reef in Simlong, Batangas City. Specifically, the study attempts to determine the macrobenthic diversity and identify environmental factors affecting coral communities. Information generated from this study would be useful in decision-policy making and public awareness in order to conserve coral reef ecosystem. Results of this study could be used as input to the monitoring program of the status of coral reefs in the country as stipulated in the Philippine National Plan of Action for the Coral Triangle Initiatives. Methodology Sampling Using SCUBA, the coral reef in Barangay Simlong, Batangas City (Fig.1 c/o Simon) was surveyed to assess its macobenthic diversity and current state. Sampling was done using photo transect technique (Figure 2). Three 5 m bands with 30 meter length (COORDINATES c/o Simon; map c/o Mary Anne) were laid on the coral reef at a depth of 8 m on 15 September 2013 in the morning. Each transect consisted of 30 randomly sampled quadrats, each measuring 1 m x 1 m with 25 equal grids. A total of 90 sampling points were taken for the 3 transects. Photos of the substrate per quadrat were captured using digital camera with waterproof housing. 
Figure 2. Photo transect method with quadrat. Data Analysis Identification of macrobenthos was done using a computer with the aid of Picasa photoviewer and Windows photoviewer. All taxa within each quadrat sample were identified to the lowest possible taxonomic level using published field guides (White, 2001; Colin & Arneson, 1995) and online databases (http://coral.aims.gov.au/info/spatial.jsp; SeaLifeBase, 2013 ). Percentage composition of benthos cover was estimated using the formula below: 
The following abbreviations of life forms are used: AA algal assemblage; BC branching coral; CA coralline algae; DC dead coral; DCA dead coral with algae; DGC digitate coral; EC encrusting corals; FC foliose corals; MC massive corals; SC solitary corals; SFC soft corals; SMC submassive coral; TC table corals; OT others. Results and Discussion Macrobenthos encountered in the sampling area and their corresponding percentage cover are presented in Table 1. In terms of diversity of hard corals, there are 27 genera belonging to 13 families, mainly dominated by the families of Poritidae, Faviidae, and Milleporidae with percentage cover of 32.6%, 26.2% and 9.7%, respectively (Fig. 3). Figure 4 shows the percentage composition of coral cover by genus with Porites (32.6%) as the most dominant genus, followed by Favites (14%) and Millepora (9.7%). The number of genus in the families ranges from 1 to 6 with family Faviidae having the most diverse comprising 6 genera, followed by Acroporidae consisting of 4 genera and then both Fungiidae and Mussidae containing 3 genera. Considering both hard and soft corals, the same trend was observed wherein the reef is mainly represented by Porites (Poritidae), Favites (Faviidae) and Millepora (Milleporidae) as depicted in Figure 5. These corals occur mostly in Indo-Pacific (SealLifeBase, 2013; Veron, 2000). Table 1. Macrobenthos and their corresponding percentage cover.
Figure 3. Percentage composition of hard coral cover by family (TO BE REPLACED) 
Figure 4. Percentage composition of coralcover by genus. 
Figure 5. Percentage composition of live coral cover. In this study, the natural predators of corals identified are corallivorous fish mainly represented by butterflyfishes (Chaetodontidae) and angelfishes (Pomacanthidae). Coralivores function as indicator species in coral reef ecosystem. Their abundance and biomass are relatively low which indicates that the reef is under poor condition. The Other taxa collectively represent 6% of the total cover. These include sponges (Porifera), clams and gastropods including nudibranchs (Mollusca), sea worms (Annelida), tunicates (Chordata), sea anemone and sea ferns (Cnidaria), and Diadema and crinoids (Echinodermata). In terms of variety of coral life forms, the massive corals have the highest percentage cover (~14%) and the table corals have the least (0.13%) as depicted in Figure 6. The different growth forms represent adaptations to different environmental conditions. The massive and encrusting forms are wave-resistant. Branching forms are less wave-resistant, but they can survive higher sedimentation rates than many massive corals (http://www.coexploration.org/bbsr/coral/html/body_basic_coral_biology.html). Since coral of massive life form dominates the coral community in the site, it implies that that the study area is exposed to strong wave action and strong current. Thus, it is not surprising therefore that table and foliose life forms are less likely to dominate the area. 
Figure 6. Percentage composition of macobenthos cover. More than 30% of the total cover in the sampling area is represented by abiotic components. They consist of sand, silt/sediments and rubble, and have the highest percentage cover (Figure 6). Their percentage cover (31.7%) is a little higher than the combined hand and soft corals (31.2%). It is also clear that there is a high percentage cover of dead corals, when both dead corals with algae (DCA) and dead corals (DC) are pooled together (~25%). This is indicative of an unstable and under stress environment. Furthermore, the high dominance DCA can be attributed to high concentration of nutrients or presence and or absence of herbivores and coralivores. The concentration of nutrients in the area was not determined in this study. However, based on phytoplankton biomass assessment, the study area is classified as _________(eutrophic?) (see section of this report). The low abundance of coralivores and herbivores implies that they are not the major limiting factors of coral diversity. Sedimentation/ siltation was observed to be high near the sampling area. This was demonstrated by the high percentage cover of abiotic component composed mainly of sand/silt. Possible source of influx of sediments are believed to be from the connecting river and land-based developments. This may explain also the high percentage cover of dead corals (~25%) in the study area. Corals lack mobility which make them vulnerable to siltation, through smothering and oxygen depletion (UNEP/IUCN, 1988S). Their growth rate is altered in areas where sediments are regularly disturbed and silted substrates inhibit larval settlement (UNEP/IUCN, 1988). Pollution perhaps is a major driver of ecosystem change in Simlong. A portion of the shoreline near the study site has been used as dumping site of waste by the local community (Figure c/o Simon). Simlong is a highly industrialized area. Effluents generated from the industries may affect water quality and ecosystem functions and processes in the marine environment. Recommendations To fully understand the state of coral reef in the study area, both spatial and temporal variability of coral reef biodiversity across Simlong should be carried out. Nutrient concentrations should be determined to correlate this to current biodiversity of coral reef. Sedimentation/siltation rate should be studied to assess its impacts (photosynthesis, smothering of corals) to coral communities. It is also recommended that the dump site of solid waste near the shore should be cleared. References Australian Institute of Marine Science. 2013. AIMS Coral Fact Sheets. Viewed September 2013. http://coral.aims.gov.au/info/spatial.jsp Colin, P.L. and A.C. Arneson. 1995. Tropical Pacific Invertebrates. A field guide to the marine invertebrates occurring on tropical Pacific coral reefs, seagrass beds and mangroves. USA. 296 p. Republic of the Philippines. National Plan of Action for the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security. DENR-PAWB, QC, Philippines, 88 p. Ross, M.A. and G. Hodgson. 1981. A quantitative study of hermatypic coral diversity and zonation at Apo Reef, Mindiro, Philippines. Proceedings of the Fourth International Coral Reef Syposium, Manila 2:281-291. SeaLifeBase, 2013. http://www.sealifebase.org/ UNEP/IUCN. 1988. Coral Reefs of the World. Volume 3: Central and Western Pacific. UNEP Regional Seas Directories and Bibliographies. IUCN, Gland, Switzerland and Cambridge, U.K./UNEP, Nairobi, Kenya, xlix + 320pp. Veron, J.E.N. 2000. Corals of the world. Volume 3. Australian Institute of Marine Science and CRR Qld. Pty. Ltd. Australia. 490 p. White, A.T. Philippine Coral Reefs. 2001. A Natural History Guide. Bookmark, Inc. and the Sulu Fund for Marine Conservation Foundation. Hong Kong. 276 p. |