Preliminary Results of Coral Recruitment in Pulau Redang

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1 PRELIMINARY RESULTS OF CORAL RECRUITMENT IN PULAU REDANG Preliminary Results of Coral Recruitment in Pulau Redang Kee Alfian Abdul Adzis 1*, Tatsuki Toda 2 & Othman Haji Ross 1 1 School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, MALAYSIA. 2 Department of Bioengineering, Faculty of Engineering, Soka University, Hachioji, Tokyo, JAPAN * Correspondence alfian@pkrisc.cc.ukm.my ABSTRACT Recruitment is one of the critical processes in the persistence of corals. It is important to understand the recruitment of Pulau Redang in order to assess the development of coral reefs along with the development of the island. Five sites were chosen and unglazed ceramic tiles were used as artificial substrate. The tiles were submerged for a total of 67 days before retrieval. Pasir Akar area recorded the highest recruits with a value of 0.43 recruits/tile/day, while Pulau Lima area recorded the lowest recruits with a value of 0.01 recruits/tile/day. Pocilloporidae, acroporidae and an unknown species were identified. Pocilloporidae recorded a mean value of 0.11 ± 0.66 recruits/tile/day, followed by acroporidae with a mean value of 0.03 ± Polychaete recorded a mean percentage of ± 5.00%, followed by Bryozoan and Others with a mean percentage of ± 7.18% and 2.47 ± 2.23%, respectively from the total recruits. Coral recruitments in Pasir Akar and Teluk Mat Delah is considered high in comparison with other places in east coast of Malaysia Peninsular waters and Australian waters. Current flow was one of the factors influencing the high and low recruits in Pulau Redang. Generally, Pulau Redang coral recruitment is high compared to different areas in the island. In the future study, parameters such as algae biomass, current flow data and seasonal pattern will be considered towards further understanding its influence on the recruitments of coral around Pulau Redang. ABSTRAK Pengrekrutan merupakan salah satu proses kritikal dalam penerusan kewujudan karang. Ia adalah penting untuk memahami pengrekrutan karang di Pulau Redang, yang mana ia juga memberikan penilaian dalam keadaan terumbu karang selaras dengan pembangunan yang sedang dijalankan di pulau tersebut. Lima lokasi telah dipilih dan 91 91

2 EKOSISTEM MARIN MALAYSIA: PELUANG & PENYELIDIKAN TERKINI jubin yang belum disadur digunakan sebagai substrat tiruan. Jubin-jubin tersebut diletakkan dalam air laut selama 67 hari sebelum ia dikutip semula. Kawasan Pasir Akar telah merekodkan pengrekrutan yang tertinggi dengan nilai 0.43 recruits/tile/day, manakala Pulau Lima merekodkan pengrekrutan yang terendah iaitu dengan nilai 0.01 recruits/tile/day. Pocilloporidae, acroporidae dan satu spesies yang belum dikenal pasti telah dicam. Pocilloporidae telah merekodkan nilai min iaitu 0.11 ± 0.66 recruits/tile/ day, diikuti dengan nilai min acroporida iaitu 0.03 ± 0.01 recruits/tile/day. Poliket merekodkan min peratusan ± 5.00%, diikuti oleh Brozoa dan lain-lain dengan masing-masing mencatatkan min peratusan ± 7.18% and 2.47 ± 2.23%. Pengrekrutan karang di Pasir Akar dan Teluk Mat Delah dikira tinggi jika ia dibandingkan dengan kawasan perairan timur Malaysia dan perairan Australia. Aliran arus merupakan salah satu faktor yang mempengaruhi tinggi dan rendah pengrekrutan karang di Pulau Redang. Secara umumnya, pengrekrutan karang di Pulau Redang adalah tinggi jika dibandingkan dengan kawasan lain di pulau tersebut. Untuk kajian di masa hadapan, parameter seperti biomas algae, data aliran arus laut dan corak musim monsun akan diambil kira dalam pemahaman lanjutan pengaruh yang memberi kesan terhadap pengrekrutan karang disekitar Pulau Redang. Keywords: Coral recruitment; Pocilloporidae; Acroporidae; current flow. Introduction Coral recruitment is one of the critical processes which the persistence of coral reefs depends on (Richmond 1997). It is the process by which newly formed individuals become a part of the reef community. It is important to understand and monitored the recruitment of the corals because the survival and longevity of the coral reefs depends on the recruitment of new juveniles in the area. Coral recruitments is known to be influence by several environmental factors such as seasonality (Banks & Harriott 1996; Gleason 1996; Tanner 1996), depth (Gleason 1996; Wallace & Bull 1981), substratum orientation (Baggett & Bright 1985; Gleason 1996), sedimentation (Richmond 1997; Gilmour 1999) and settlement cues (Morse et al. 1988; Van Moorsel 1989; Richmond 1997). Pulau Redang is one of the islands that were gazetted as a marine park under the Fisheries Act It is located in the state of Terengganu and is one of the best diving spot for diving enthusiast. Development on the island has catch up with the building of more chalets in order to accommodate the increasing numbers of tourist visiting the island. Ibrahim (1992) has reported that sedimentation levels in Pulau Redang are increasing, it is predicted the rate will increase with the development plan of Pulau Redang. Recently, Nik (2003) has also reported that Pulau Redang is showing some indication of stress from the development activity that is carried out. Therefore, Pulau Redang coral reefs are expected to slowly degrading due to anthropogenic factors cause by various developments on the island. This study was carried out to monitor the recruitment of juvenile corals around Pulau Redang in order to assess the development of coral reefs in the area. A better understanding of the coral recruitment and mortality levels of the area can help in managing conservation effort in Pulau Redang

3 PRELIMINARY RESULTS OF CORAL RECRUITMENT IN PULAU REDANG Materials & Method A total of five sites were chosen; Marine Park (T. laut), Pulau Lima, Teluk Mat Delah, Teluk Mak Simpan and Pasir Akar. Unglazed ceramic tiles were used for coral recruitments and a total of 44 tiles for each sites were submerged. The tiles were arranged with different orientations and exposure. For the present paper, the tiles were submerged for a total of 67 days before retrieval (06 August October 2003). Tiles that were retrieved were bleach by using 10% Sodium hypochlorite or commercial bleach to remove all organic materials. The tiles were then dried and hard coral recruits were counted and identified under a stereomicroscope. Other organism were also identified and grouped as polychaete, bryozoans (by colony) and others. Results Coral Recruits All of the station used the same type of tiles, which is to standardize the comparison in recruitment between different areas in Pulau Redang. Figure 1 show that station Pasir Akar has the highest recruits with value of 0.43 ± 0.11 recruits/tile/day, whereas Pulau Lima recorded the lowest recruits with a value of 0.01 ± 0.01 recruits/tile/day. The recruitment rate recorded in Pasir Akar is considered to be high if compared with the work that was conducted by Maekawa (2003) in Tioman Island (0.06 recruits/ plate/ day) and Banks & Harriott (1996) at rocky reef of GBR (0.08 recruits/ plate/ day). Recruits/Tile/Day 0,5 0,45 0,4 0,35 0,3 0,25 0,2 0,15 0,1 0,05 0 Plima TMD Maksimpan Tlaut P.Akar Station Coral Recruit FIGURE 1: Coral Recruits Between Stations in Pulau Redang Three species of coral recruits were identified; Pocilloporidae, Acroporidae and Unknown as shown in Figure 2. Pocilloporidae recorded a mean value of 0.11 ± 0.66 recruits/tile/day, followed by acroporidae with a mean value of 0.03 ± The highest recruits of Pocilloporidae were recorded in Pasir Akar with a value of 0.36 ± 0.01 recruits/ tile/day. The highest recruits for Acroporidae were also recorded in Pasir Akar with a 93 93

4 EKOSISTEM MARIN MALAYSIA: PELUANG & PENYELIDIKAN TERKINI Recruits/Tile/Day Pocilloporidae Acroporidae Unknown Pilma TMD Maksimpan Marine Park P. Akar Station FIGURE 2: Coral Recruits Between Different Stations in Pulau Redang value of 0.07 ± 0.06 recruits/tile/day. The unidentified recruits were only found at Pulau Lima and Teluk Mat Delah but in a very low numbers, ± recruits/tile/day and ± recruits/tile/day respectively. Other Invertebrates Figure 3 shows the recruitment of other invertebrates in Pulau Redang. Generally, polychaete is the highest recruits on the tiles where it dominates more than 50% of recruitment at all stations. Polychaete recorded a mean percentage of ± 5.00%, followed by Bryozoan and Others with a mean percentage of ± 7.18% and 2.47 ± 2.23 respectively. The highest polychaete recruitment is at Teluk Mat Delah station where it dominates 81.08% (0.917 recruits/tile/day) of the total recruitments. This group recorded the lowest recruitment at Marine Park with a percentage of 52.94% (0.212 recruits/tile/ day). Bryozoan recorded its highest recruitment at Taman Laut with a percentage of 42.3% (0.17 recruits/tile/day) and the lowest recruitment at Teluk Mat Delah with a percentage of 3.46% (0.039 recruits/tile/day) from the total recruitments

5 PRELIMINARY RESULTS OF CORAL RECRUITMENT IN PULAU REDANG a ) % 2% 0.00 b) 0% % % % % % c) % 9% d ) % % % % % % e) % % Coral Recruits B ry ozoa n P oly cha ete Ot hers % % FIGURE 3: The Total Recruits of Organism at Each Station. (a: Pulau Lima; b: Teluk Mat Delah; c: Teluk Mak Simpan; d: Marine Park; e; Pasir Akar) 95 95

6 EKOSISTEM MARIN MALAYSIA: PELUANG & PENYELIDIKAN TERKINI Discussion The recruitment of corals in various sites in Pulau Redang generally shows a clear difference between each site. The highest recruitment was recorded at Pasir Akar and Teluk Mat Delah. Both of these sites are quite protected where it is located in a bay, compare to the other sites that are exposed to direct current flow. Pasir Akar is an area that was designated as a research zone. Tourist activity in this area is minimal and frequently monitored by the marine park rangers. The anthropogenic factor in this area can be considered low. Teluk Mat Delah is located north of Pulau Redang and it is quite protected. This area is one of the frequent visited sites for snorklers and divers. The coral community here is vase and there is hardly any sandy patch among the reefs. Both of these sites have a very minimal current effect as it is located in a bay. As for Pulau Lima, Teluk Mak Simpan and Marine Park Jetty, the current flow in this area is quite strong. Pulau Lima is a known area for drift diving. After spawning, coral juveniles will be in planktonic stage for 4 days or more before it is ready to settle on suitable substrates (Richmond 1997). It is predicted during that period the juveniles will be drifted away from its spawning location. The depth between sites also plays a role in the difference of recruitment, Pulau Lima is the deepest area (13 meters) and Marine Park is the shallowest (3 meter). Various studies have reported that depth can have a major effect on the recruitment success of the juvenile corals (Birkeland 1981; Fitzhardinge 1988; Riegl 1995; Richmond 1997; Maekawa 2003). From this study, the highest recruitments were found in the depth of 25 feet (Pasir Akar & Teluk Mat Delah), which shown it might be the optimum depth for coral recruitments. Three species was found recruiting on the tiles during the duration of this study; Pocilloporidae, Acroporidae and Unknown. Pocilloporidae has the highest recruits followed by Acroporidae and an Unknown species. The unknown species was only found in Pulau Lima and Teluk Mat Delah which is the south-east and north-east coast of Pulau Redang. It is cumbersome to identify the juvenile corals due to the facts that the corallite at its earlier stage is almost identical between genus (English et al. 1994). Teluk Mat Delah was the only area in the island that recorded Pavona frondifera and Psammocora haimeana species by Harborne et al. (2000). It is suspected that the unknown species is belonging to the group. Currently, confirmation and consultation with other expert is undergoing. Generally, all sites were only dominated by two species. This situation was also observed by Maekawa (2003) in Pulau Tioman. Both Pocilloporidae and Acroporidae is opportunistic species (Lam 2003), which means they have the ability to settle fast on area that is available. This makes them the dominant recruits at most of the sites in Pulau Redang. Different reproduction strategy also plays a role in the different dominant recruits that was found. Pocilloporidae belongs to the brooder group and Acroporidae belongs to the broadcast spawner group. Brooder group fertilize their eggs internally with the embryo developing to the planulae stage inside the coral polyp (Maekawa 2003). As for broadcast spawner group, it releases eggs and sperms into the water column where external fertilization and development take place (Maekawa 2003). These two modes of reproduction cause it to have different competency periods, availability of zooxanthellae 96 96

7 PRELIMINARY RESULTS OF CORAL RECRUITMENT IN PULAU REDANG on the planulae and dispersal of larvae (Richmond 1997). This factor is important to the readiness of the larvae to settle on suitable substrate. Brooder group coral larvae; Pocilloporidae, have shorter competency period, it is ready to search and settle once it is release from its parents polyp. Pocilloporidae have the tendency to settle near to their parent colony (Harii et al. 2002) compare to Acroporidae which have longer competency periods and will drift along with the current before it is ready to settle on suitable substrate (Maekawa 2003). It is also important to understand the relationship between coral recruits and other invertebrates. Settlement of the other invertebrates might restrain coral recruitments in their competition for space (Richmond 1997; Maekawa 2003). In Pulau Redang, the polychaete group was found to be the most dominant recruits compare to the others. It dominates 50 % of the total recruits at all stations. Besides other invertebrates, algal was also an important spatial competitor (Richmond 1997; Gleason 1998; Miller et al. 2000; Maekawa 2003). Unfortunately, the algal biomass during this preliminary work was not estimated due to the bleaching method that cleaned away any algae that were presence. In the future research, algae biomass will be considered by extracting chlorophyll a. Generally, coral recruitment in Pasir Akar and Teluk Mat Delah considered being high if compared with Harriott & Banks (1995) in Salitary Island, Australia (0.044 recruits/ plate/day) and Banks & Harriott (1996) in Gneering shoals, Australia (0.082 recruits/ plate/day). The low recruits in Pulau Lima and Marine Park might due to the strong current effect as both of these areas have a strong current flow (personal encounter). Harriott & Bank (1995) stated that their low recruits is due to the strong current that swept away the coral larvae supply in the area. Future investigations are needed to further understand the relationship between coral recruitments and current flow. In conclusion, Pulau Redang coral recruitments are different between areas in the island. Some of the areas has good recruitments rate and other places needed to be monitored. The time-frame of this research will be extended to look at its seasonal pattern, and algae biomass and current flow will be added into future work. Acknowledgements This study was funded by The Japan Society for Promotion of Sciences (JSPS) and Univerisiti Kebangsaan Malaysia (UKM). Cooperation and materials support were provided by INAX Company, Japan. References Baggett L.S., Bright T.J Coral recruitment at east flower garden reef. Proceeding of the Fifth International Coral Reef Congress, Tahiti, Vol 4. Pp Banks S.A., Harriott V.J Patterns of coral recruitment at the Gneering shoals, southeast Queensland, Australia. Coral Reefs, 15: Banks, S.A., Harriott V.J Patterns of coral recruitment at the Gneering shoals, southeast Queensland, Australia. Coral Reefs, 15: Birkeland C., D. Rowley, R.H. Randall Coral recruitment patterns at Guam. Proceeding of the Fourth International Coral Reef Symposium, Manila. Vol

8 EKOSISTEM MARIN MALAYSIA: PELUANG & PENYELIDIKAN TERKINI Fitzhardinge R. C Coral recruitment: the importance of interspesific differences in juvenile growth and mortality. Proceeding of the 6 th International Coral Reef symposium, Australia, 2: Gilmour J Experimental investigation into the effects of suspended sediment on fertilisation, larval survival and settlement in a scleractinian coral. Mar. Biol., 135: Gleason, M.G Coral recruitment in Moorea, French Polynesia: the importance of patch type and temporal variation. J. Exp. Mar. Biol. Ecol., 207: Harborne, A., Fenner, D., Barnes, A., Beger, M., Harding, S. & Roxburgh T Status report on the coral reefs of the east coast of Peninsular Malaysia. Pp Coral Cay Conservation Ltd: United Kingdom. Harii S., H. Kayanne, H. Takigawa, T. Hayashibara, M. Yamamoto Larval survivorship, competency periods and settlement of two brooding corals, Heliopora coerulea and Pocillopora damicornis. Mar. Biol., 141: Harriott, V.J. & Banks, S.A Recruitment of scleractinian corals in the Solitary Islands Marine Reserve, a high latitude coral dominated community in Eastern Australia. Mar. Ecol. Prog. Ser., 123: Ibrahim, M. Hj. M., Aziz, H.A. & Ahmad, S.B The impacts of resort development on the coral reefs of Pulau Redang Marine Park. Third Asean Science & Technology Week Conference Proceedings Volume 6, Marine Science: Living Coastal Resources, Singapore, Pp Lam K.K.Y Coral recruitment onto an experimental pilverised fuel ash-concrete artificial reef. Marine Pollution Bulletin, 46: Maekawa, T Coral recruitment study in Tioman Island, Malaysia. Master Dissertation. Soka University, Tokyo. Miller M.W., E. Weil, A. M. Szmant Coral recruitment and juvenila mortality as structuring factors for reef benthic communities in Biscayne National Park, USA. Coral reefs, 19: Morse, D.E., Hooker, N. Morse, A.N.C. & Jensen, R.A Control of larval metamorphosis and recruitment in sympatric Agariciid corals. J. Exp. Mar. Biol. Ecol., 116: Nik, M.M Redang: A marine park in name only? Malaysian Naturalist, 56(3): Richmond, R.H Reproduction and Recruitment in Corals: Critical Links in the Persistence of Reefs. Dlm. Birkeland, C. (pnyt.). Life and death of coral reefs. hlm London: Chapman and Hall. Riegl B., G.M. Branch Effects of sediment on the energy budgets of four scleractinian (Bourne 1900) and five alcyonacean (Lamouroux 1816) corals. J. Exp. Mar. Biol. Ecol., 186: Tanner J.E Seasonality and lunar periodicity in the reproduction of Pocilloporid corals. Coral Reefs, 15: Van Moorsel, G.W.N.M Settlement of stony corals (scleractinia) on artificial substratum on a Carribbean reef: spatial aspects. In: Van Moorsel, G.W.N.M. (ed.) Juvenile ecology and reproduction strategies of reef corals. Pp Artigrafica, Den Helder. Wallace, C.C. & Bull, G.D Patterns of juvenile coral recruitment on a reef front during a spring-summer spawning period. Proceeding of 4 th International Coral Reef Symposium, Manila, Pp

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