Boracay Coral Health

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Water Quality and Coral Reef Health In Boracay, El Nido, Isla Verde, and Balicasag, Philippines August 1997 Draft August 27 1997 Revised September 13 1997 Thomas Goreau Maya Goreau James Cervino SUMMARY Coral reefs and coastal habitats were examined during August 1997 at a range of Philippine sites ranging from high to low human impact. 18 out of 23 locations (78.3%) showed moderate to high levels of algae growth, indicating that they are currently exposed to elevated levels of nutrients. The amount of algae at most sites appeared to primarily reflect sewage runoff from groundwater, but some sites located off uninhabited islands appeared also to be affected by nutrients from episodic upwelling of nutrient-rich deep waters. Because coral reefs will be killed by algae overgrowth fertilized by waste-derived nutrients before bacteria reach levels which are dangerous for human health, coral reef assessment should focus on monitoring and assessing the factors leading to algae proliferation in reef habitats, along with detailed year round monitoring of nutrients in order to identify their source regions, and with a focus on assessing coliform bacteria only in severely polluted areas. Such work should be done by greatly expanding the monitoring capability of DENR and the research capability of Philippine marine research institutions. Protection of the remaining reefs still in good condition will require program s to develop sewage treatment to tertiary level and to use dry composting toilets in non-sewered communities, while ending destructive and non-sustainable fishing practices. Only then will Philippine reefs be able to safeguard the future of the nation’s fisheries, tourism, biodiversity, and shore protection. BORACAY The first eight sites mark the eight locations which were concurrently monitored by DENR. We went out with them on their routine sampling, and made observations at the same sites. Following the controversy over water quality at Boracay, DENR initiated biweekly measurements at 15 sites, to continue for a year. Due to weather considerations, the sites on the rougher western side had been omitted in previous samplings, so the focus was on that side even though the seas was rough. Due to lack of time only 8 of the 15 sites could be monitored. 5 sites were examined on the west side of the island, spanning its whole length, and one site each on the north, south, and east sides. We observed that while measurements were made of the temperature, salinity, pH, oxygen, and turbidity of the water, and water samples were collected for analysis of coliform bacteria, nutrients, and biochemical oxygen demand (BOD) by the DENR / DOH / DST team, no ecological assessment was included in the monitoring program . We therefore felt that the most useful addition to their program would be to film and rapidly assess the condition of the bottom marine ecosystems at each site. In addition, because this sampling was conducted in waters around 5 to 10 metres deep in a belt around 100 metres offshore we supplemented this with water sampling and ecological observations in areas both offshore and inshore from this transect. The following notes contain a brief summary of reef or marine ecosystem health at each site. The numbering used here is not the same as that used by DENR. Our site 1, on the southeast, corresponds to DENR site 6, site 2, located off the southwest of the island corresponds to DENR site 9, sites 3, 4, 5, 6, and 7 are taken along a south to north transect along the west coast parallel to the main beach and tourism area and correspond to DENR sites 10, 11, 12, 13, and 15 respectively, while site 8, located off the north of the island corresponds to DENR site 1. All sites are indicated on map 2. 1) This site had very low live coral cover, between 1 and 5%, and is over 90% covered with dead coral rubble. This rubble could have been caused by either old dynamite fishing or by typhoon waves, but the fact that corals are lying randomly in all directions rather than lined up in a predominant direction suggests that dynamite was responsible. The amount of rubble corresponds to what must have once been a large reef dominated by branching corals, and there has been very little recovery since its destruction. The bottom organisms are dominated by large amounts of a branching sponge, which indicates that high levels of bacteria, the food of sponges, are present in the water. The rubble is largely covered with fuzzy brown and green algae growth made up of fine filamentous algae and cyanobacteria (also known as blue-green algae) on which young corals cannot settle and grow. Sand patches between the rubble fields are also covered with cyanobacteria mats. Large numbers of algae eating black long spined sea urchins (Diadema setosum) are present, but appear not to be able to control the algae overgrowth of the hard bottom. Towards the shore there is a sand belt which is largely covered with slimy brown patches of cyanobacterial mats, which appear to be growing on nutrients which are percolating from land through the sandy beach. The water was turbid. 2) This site, located off a rocky unpopulated shore near to the well flushed channel between Boracay and Panay, was in the best condition of any near shore site seen. Live reef building corals covered around 70% of the bottom, and species diversity was high and dominated by fragile and healthy branching and plate corals. There was no rubble between the coral heads, only clean sand. This strongly suggests that typhoon damage did not cause the deterioration of inshore reefs on Boracay, and that dynamite is likely to have been the cause of destruction seen at other sites. The water was blue and far clearer than at any other near shore site seen. Large algae, turf algae, and cyanobacteria were very rare or altogether absent. 3) This site was dominated by broken dead branching coral rubble and small dead coral heads, with sand in between. Live corals were small and covered about 20% of hard bottom. Fuzzy algae turf and red and brown cyanobacterial mats covered a large portion of the dead corals. Although the water was turbid, this site had either been less severely damaged than the first site, or had managed to recover slightly. 4) This site was dominated by sand, which was clean, white, and ripple marked, indicating that it was not stabilized by surface cyanobacterial mats as at other sites. Patches of hard bottom had low live coral cover, and were dominated by soft corals or dead corals and rubble covered with fuzzy cyanobacteria. The water was turbid. 5) This site was dominated by sand and seagrass beds. The water was turbid and there were almost no live corals, except for a handful of small colonies. The sand was covered with patchy mats of cyanobacteria. The seagrass was distinctly eutrophic in appearance, containing large amounts of the algae Hypnea musciformis, Dictyota sp., and Galaxaura oblongata, overgrown with Chaetomorpha linum and cyanobacteria. 6) This site was dominated by sand, with some seagrass. The seagrass had large clumps of the eutrophic alga Hypnea musciformis, but overall the level of algae in both seagrass and sand were less than at the previous site. The water was turbid. There was a single very large coral mound, covered with small to medium sized corals up to a metre across, and with cyanobacterial turf on dead coral surfaces. 7) This site was dominated by sand with small coral heads. Coral heads covered about 30 percent of the hard bottom, and colonies were small. The water was turbid. The bottom appeared very fuzzy due to dense mats of brown cyanobacteria on sand and dead coral rubble. Large green algae turfs, probably Anadyomene or Microdictyon sp., were found on rubble and dead corals. 8) This site was dominated by branching coral rubble, with only small amounts of interstitial sand. The rubble appeared to have been caused by dynamite. No live corals were seen. Fuzzy filamentous algae turf, overgrown by cyanobacteria, covered the dead coral rubble. Small clumps of the weedy alga Acanthophora spicifera were present, along with larger patches of the beneficial sand-producing green alga Halimeda sp. 9) Inshore sandy areas along the beach running along the western shore of the island were covered by cyanobacterial mats. Seagrass areas were distinctly eutrophic with weedy algae, especially the fuzzy green filamentous alga Chaetomorpha linum. This species is a major indicator of high levels of nutrients, in particular phosphorus, which is usually derived from sewage and from detergents. Chaetomorpha was present in small clumps around the bases of the seagrass. This species is especially dangerous because when the water is calm and nutrients build up it is capable of forming long green strands similar in appearance to cotton wool, which are broken off by waves and can be wrapped completely around corals and smother them. It is also certainly the green algae which locals describe as competely covering the inshore sandy areas from January to March, and which forms thick floating mats which wash ashore and must be raked off daily. Although some locals feel that this algae turns into sand this is completely incorrect. Those calcareous algae which turn white and turn into sand when they die, like Halimeda and Galaxaura, do not float, and they are being overgrown by non sand producing weedy species. Chaetomorpha does turn white when it dies, but this is because the green chlorophyll is rapidly destroyed, and the resulting material rots before it can dry, and ultimately decomposes completely. This species is a favorite food of surgeonfish. Local sources indicate that this algae used to bloom briefly in front of the beach at the calmest times, but that the extent and duration of the bloom have steadily increased over the last 10 years and become a season long problem which negatively affects the water bathing quality, as swimmers can not see the sand bottom, and must step on and be wrapped up in large green streamers. This alge species has been a major coral reef killer in other parts of the world. The only effective control known is to cut off its supply of nutrients from land. One bay in Jamaica where the beach and seagrasses, along with the reef, were being overgrown by Chaetomorpha linum and other weedy algae was successfully cleaned up last year by diverting all sewage and detergent from disposal in the sea, and applying it instead to water and fertilize lawns and ornamental vegetation. The weedy algae had visibly decreased within weeks, and were almost completely gone within two months (Goreau et al, in press). This indicates that nutrient reduction can be extremely rapid and effective if it is sufficiently large in magnitude. The same strategy is likely to be the only one which can work in Boracay, as the algae grows so fast when nutrients are high that it is virtually impossible to remove it. In addition to Chaetomorpha, large amounts of other weedy algae were washed up on the beach, including Hypnea musciformis, Acanthophora spicifera, Dilophus alternans, Gracilaria sp., and a calcareous branching red alga resembling Haptolithon or Corallina. To determine if groundwater seepage is enriching nutrients in the nearshore zone, water samples were collected off the beach in waters one metre deep, and groundwater samples were obtained from a local well. 10) Santos Place, offshore northwest Boracay. Surface water sample collected. The reef at this site was located on a smoothly sloping bottom, and was composed of around equal amounts of soft corals and hard corals. Visibility was good, a bit less than 20 metres. The site is subjected to episodic high wave energies, which appear to favor soft coral growth and rounded massive hard corals. The corals were in good health, and there were no large algae or cyanobacterial mats. Sand between coral mounds was clean and free of cyanobacteria. Dead coral surfaces were overgrown with encrusting calcareous red algae crusts, which produce a limestone cement, and are typical of low nutrient conditions. However these were affected to some degree by the recently discovered Coralline Lethal Disease (Goreau, et al, in press). This disease, of unknown origin, kills pink coralline algae crusts. A spreading white rim marks the boundary between pink algae and dead areas overgrown with a green filamentous alga. The disease, which has also been found all across the Caribbean and in the southwest Indian Ocean, appeared to be moderately advanced compared to those other areas. 11) Angol, offshore southwest Boracay. Surface water sample collected. The reefs at this site, although rarely dived on, are regarded by local dive masters as typical of the offshore reefs of western Boracay. The reef was in excellent condition. The visibility was good, over 20 metres. Live coral covered over 90% of the bottom, with very high species diversity, large healthy corals, and good vertical growth. No weedy algae or cyanobacteria were seen. There was little dead coral, and this was covered with the encrusting calcareous red algae, Porolithon, which was somewhat affected by CLD. Diseases were also seen on several coral species, including white band disease on branching Acropora and an unidentified line disease on Porites. The excellent condition of this reef indicates that the source of nutrients must be from the island and not from water masses being pushed onto the island by the southwest monsoon, and that the negative impacts seen in inshore areas have not yet reached the area, even when the wind pattern reverses. This area, around a kilometer from shore, provides prime diving which has not yet been negatively impacted. If nutrient sources from the island can be cleaned up, the reef has excellent prospects for being sustained in prime condition. Moorings should be installed at all dive sites to avoid anchor damage, and tourists rigorously trained to maintain their buoyancy and not touch the corals. 12) Laguna de Boracay, offshore east Boracay. Surface water sample collected. Visibility was poor, less than 10 metres, and the water was green and full of suspended organic matter. There were large amounts of soft coral, and hard coral diversity was lower than on the other side of the island. The reefs had large amounts of algae, including thick gooey cyanobacterial mats overgrowing dead and living corals, filamentous algae turfs, and large clumps of the sand producing algae Halimeda and Galaxaura. This algae abundance was somewhat surprising given that this side of the island was calm and protected, and indicates that nutrient inputs must be considerable. Little diving takes place on this side because reefs are not in as good condition. The clear evidence of eutrophication suggests that a major source of nutrients may lie in discharges of sewage contaminated groundwater from local populations in the interior villages. Although there is still little tourism development on this side of the island, the majority of local residents live in the villages in the interior, and the major natural drainage of wetlands and seasonal streams is towards this side. Any further sewage drainage into this area, whether from increased local populations, new tourism developments on the north and east, the large golf course being constructed, or sewage discharge will cause the reefs to deteriorate further unless strict measures are taken to absorb the nutrients before they can reach the sea. Sewage treatment Boracay has a beautiful beach which unfortunately shows classic signs of the impacts of uncontrolled and excessive development in advance of developing sewage treatment infrastructure needed to protect its natural beauty. While existing data indicates that water quality is generally adequate for bathing, it is episodically unsuitable, especially at the peak of the tourist season when the beach is calm, and rainfall is low. The ecological observations show significant impacts on nearshore and eastern reefs, but western reefs are still in good shape. Protection of the good reefs and restoration of damaged areas will take time once water quality is improved, but that nutrients will need to be reduced to below coral reef eutrophication levels first. At present the island has little or no suitable sewage treatment for a coral reef area. Most of the resident population of around 10,000 people disposes of their sewage directly into pits in the ground or into surface drainage, which soaks directly through the porous sand and limestone into the sea. While some hotels have septic tanks this is not sufficient to solve the problem. First, there are no facilities to pump out the tanks, so they fill up and the excess flows into the groundwater. Secondly, building extra chambers is not a solution, as the bulk of the nutrients generated by decomposition of wastes go into solution and are not removed in the tanks and are discharged into the ground in the overflow. DOT, recognizing the importance of maintaining water quality in Boracay for the viability of the tourism industry, has obtained funding from the Government of Japan’s Overseas Development Assistance Program for building a safe water supply for residents (who now use polluted groundwater wells) and a sewage collection and treatment system. Construction is due to start next year. We met with the sewage design team, and found them to highly knowledgeable and competent. Unfortunately though, the plans now being used are inadequate to reduce nutrients to safe levels for the reef. This is not the fault of the design team, who are fully aware of the problems, but due to inadequate funds for a complete system which treats the sewage to a level which allows the waste effluents to be reused on land and the nutrients to be absorbed by land vegetation (biological tertiary treatment) and prevented from reaching the sea where they over fertilize the reefs and seagrasses. The sewage design team were aware or the need for further treatment, and wished to see the effluents re-used to fertilize land plants in either managed or natural wetlands or on the golf course. Due to their terms of reference they are unable to recommend application to watering the golf course greens, even though this would both absorb nutrients which must be prevented from entering the sea, while at the same time avoiding the need for importing expensive chemical fertilizers which are likely to leach into the nearshore zone through the limestone. Due to lack of funding and inadequate areas of natural wetlands, the designers were instead forced to compromise with an ocean outfall design. The consequence of the present design is that while this system will greatly improve the bacterial water quality on the beach side, it will have the effect of concentrating all the island’s nutrients on the already impacted eastern reefs, and accentuate ecological stress on that side especially during the calm season. In our view additional funds should be sought to solve the environmental health problems by adding a tertiary treatment phase to the current sewage plans, so that effluents are not discharged into the sea but instead used to fertilize wetlands, golf course greens, and ornamental vegetation. Almost all the natural forest on Boracay except on some rocky and uninhabited areas in the north have been cleared, and much has been lost to the golf course and related hotel development. What is left of the vegetation is largely a low value secondary scrub or imported tree species. In our view the Government should require the golf course to use secondarily treated effluent for watering the greens, thereby freeing up the water which would otherwise have to be imported from Panay for this purpose, denying their use to local residents. A further step could be taken to establish an ecological restoration zone for forest restoration in the interior of the island in which the natural vegetation would be fertilized and encouraged to grow back. This area should be a wildlife refuge. After suitable recovery, the watering could be switched to other restoration zones, and the area opened up for nature walks, hikes, and wildlife watching, which would greatly add to the island’s tourism attractions, while providing it with a reputation as a pioneer in environmental protection and improvement. ACKNOWLEDGEMENTS This work was carried out at the invitation of the Department of Tourism of the Philippine Government. The Global Coral Reef Alliance team agreed to conduct the study on the basis of having all expenses covered, and received no salary or fee for the study. The work described could not have been carried out without the excellent logistic and technical support of those we worked with throughout this study, and the information, advice, and discussion provided by our Philippine colleagues. Although we were not able to get the names of all who helped us, we especially wish to thank the following individuals: 1) Department of Tourism: Manila: The Honorable Mina Gabor, Secretary of Tourism, Emily Bilet, Tess Fevidal , Jean , Agnes Bocar, Mignon del Rosario The Philippine Commission on Sport Scuba Diving: Geronimo Reyes, Norman Songco, Gaudencio Pena, Alberto Herrera, Heneage Mitchell Boracay: Edwin Trompeta, Francis Gentoral, Nelson Tungala, Teddy Oczon Cebu: Bebot Estillove, Christine Ordesta, Macario Mercado, Leonelo Mission Bohol: Neil Balaba, Manuel De Erio Balicasag: Norman Balili, Nonoy Norono Department of Environment and Natural Resources: Vicente Diaz, Roberto Bernal Department of Science and Technology: Reynaldo Esguerra, Froilan Dorado, Andrea 2) Diving groups: George Wegmann, Erich Gabriel, Calypso Diving, Boracay Erick Villacorte, Pangulasian Joey Lee, Miniloc Aldo Mercado, Balicasag 3) Research Institutions: International Centre for Living Aquatic Resources Management: John McManus University of the Philippines Marine Science Institute: Gil Jacinto Porfirio Alino Mary Lou San Diego-McGlone Helen Yap Edgardo Gomez 4) Non Governmental Organizations: International Marinelife Alliance: Vaughan Pratt Alejandro Ansula Haribon Foundation: Ed Thompson Ocean Voice International: Don McAllister Jaime Baquero Canadian Urban Institute Philippines: Francis Gentoral 5) Commercial: Ten Knots Development Corporation, El Nido: Emmanuel Pastores, Manager, Environment and Community Development Unit Bert Sumagaysay, Resident Engineer SGS Philippines Inc.: Jocelyn Babaan Dames & Moore, Inc.: Senen Salacup Nippon Jogesuido Sekkei Co. Ltd.: Tatsuyuki Kikuta Yolanda Mingoa CEST Inc.: Jose Ilagan 6) Local residents: Diosa Labiste, Iloilo City, Panay Mrs. ?, Barangay Captain, Isla Verde Residents of Isla Verde Residents of Balicasag