Protected and Inaccessible Reefs of Vietnam

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1 Int. J. Environ. Eng. Nat. Resour. Volume 1, Number 2, 2014, pp Received: June 16, 2014; Published: August 30, 2014 International Journal of Environmental Engineering and Natural Resources Yuri Yakovlevich Latypov A.V. Zhirmunsky Institute of Marine Biology, FEB-RAS, Vladivostok, Russia Corresponding author: Yuri Yakovlevich Latypov Abstract: Some protected and inaccessible reefs of South Vietnam were studied by SCUBA in 80-th years of the last century and at the beginning of the Decade of the current century. Optimal composition and structure of their communities, stably state that persists for more than a quarter of a century. Thanks to the protection of the reefs and the weak human impacts through their distance there are preserved rich biodiversity of corals and associated maсrobenthos, as well as a high degree of substrate coverage of live corals. Such coral reefs can be seen as a "savings bank" where of corals, the commercially important invertebrate and fish are preserved from overfishing, and this is a constant flow of maggots to areas South China Sea depleted marine resources. The high species diversity of the reef community of protected and inaccessible reefs and its ecological status require special attention, and therefore recommendations were given to the Academy of Science and Technology of Vietnam regarding the creation of a protected such area reef for the purpose of conservation and restoration of the biological diversity of the South-China Sea as a whole. Key words: Reef, species composition, structure, community, stability. 1. Introduction Coral reefs of Vietnam are an integral part of Indo- West pacific tropic center of origin and diversity of corals [1, 2]. They represent a very productive natural ecosystem with a variety of ecological niches and multiple inhabitants. At the same time, coral reefs serve as a basis for many branches of economy (fishery, construction works, SCUBA diving, etc.). They form a natural barrier against destructive energy of waves, protecting coastline from erosion. Coral reef is actually a living barrier, which permanently replaces its destroyed basis due to its growth. Besides, coral reefs through their erosion serve as a main source of sand, replenishing critically eroded coasts. Results of hydrobiological studies on coastal Mainland and the island reefs of Vietnam in recent years clearly demonstrated their biodegradable, largely due to strong anthropogenic press [3, 4]. Study of protected and best pre- served reef is necessary to determine it s damage and to develop recommendations for the restoration and preservation of disturbed communities of reef. Coral reefs are under threat worldwide. An estimated 58% of reefs are classified as threatened [5], and 11% of the original extent of coral reefs have already been lost [6]. The composition of remaining coral reefs is also changing rapidly. For example, coral cover on reefs across the Caribbean has decreased by 80% in the past three decades [7], and some formerly abundant coral species have almost disappeared from the region [8]. The causes of coral decline are thought to include a combination of direct anthropogenic factors, such as overfishing, pollution, and sedimentation [9]. Hurricanes and tropical storms are perhaps the most obvious and frequent natural disturbances affecting reef communities. They have long been recognized as being important determinants of both the structure and function of reef ecosystems. It becomes especially important to observe and explore the coral community protected and isolated reefs. It is from these reefs may replenish and restore biodiversity on the oppressed and degraded reefs.

2 93 2. Materials and Methods Using SCUBA equipment we studied the species composition and distribution of scleractinian and mass species of macrobenthos (a little more than 600 species, including 348 species of corals), structure of communities in every zone of reefs at some islands {Bath Long Vi (20 08 N, E), Hon Nai (12 03 N, E), Con Dao (8 40 N, E), and Lodd ( E, 8 39 N)}. Surveys have been done according to the generally acceptable hydrobiological method, using frames and transects method [10]. Two hundred meters transects with the footage marking were mounted in the open and closed bays, on the headlands, near rocky, stony and sandy shores in order to maximally cover the diversity of reef communities in the region of survey. Along the transects, on every square meter the quantity of branchy,massive,incrustingandfunnel-formcoloniesofs cleractinian,degreeof substrate covering with corals in the form of a frame divided into 100 squares, and the quantity of mass species of mollusks and echinoderms were accounted. In the mass accumulations of invertebrates the density of their settlement and biomass for every species on the area of m 2 were accounted. Similarity level of different communities was determined by the Serensen s similarity parameters [11] using software program STATISTICA6.0. During analysis of communities, 1250 photos of landscapes and macrobenthos taken by Olympus and Kodak cameras were used. The following designations were accepted for Figs. 1-Spongia; 2-Sarcophyton troncheliophorum; 3-Lobophytum paucijlorum; 4-L. sp.; 5-Junceella fragilis; 6-Zoanthus sp.; 7-Seriatopora hystrix; 8-Isopora palifera; 9-Acropora robusta; 10-A. nobilis; 11-A. cytherea; 12-A. millepora; 13-Montipora hispida and M. aequituberculata; 14-Pachyselis rugosa; 15-an aggregation of Fungia; 16 - Porites lobata; 17-P. cylindrica and P. nigrescens; 18-Goniopora stokesi; 19-Faviidae; 20-Leptoria phrygia; 21-Diploastrea heliopora; 22-Turbinaria peltata; 23-Spirobranchus giganteus; 24-Lambis truncata; 25-L. lambis; 26-Cyprea arabica; 27-Arca ventricosa; 28-Lopha cristagalli; 29-Tridacna crocea; 30-T. squamosa; 31-Beguina semiorbiculata; 32-Malleus malleus; 33-Culcita novaeguineae; 34-Linckia laevigata; 35-Acanthaster planci; 36-Diadema setosum; 37-Brissus latecarinatus; 38-Bohadschia graffei; 39-Holothuria atra; 40-H. edulis; 41-Stichopus variegatus; 42-Caulerpa racemosa; 43-Turbinaria ornata; 44-Dictyota indica; 45-Padina australis; 46-Laurencia obtusa; 47-Asparagopsi taxiformis; 48-Sargassum japonicum. 3. Results and Discussion Reefs of Bath Long Vi and Lodd Islands are remote from human impact areas. A large part of the reef Con Dao Islands is in a national conservation area. The company Sanest owns the Hon Nai Island. In all of these reefs, there is a restricted if any at all access to the underwater resources. By the specificity of geomorphological and climate conditions, Vietnam s adjacent reefs are clearly distinguished into two types. The first type includes the reefs with a distinct zonation (reef lagoon, reefflat, etc.) with a developed carbonate framework, so-called structural reefs [12] that are common for the tropical zone of the World Ocean. Reefs of the second type display a weak morphostructural zonation, with some zones occasionally absent. Carbonate deposits in such reefs comprise only coral settlements of a low thickness, hardly changing the overall substrate profile (Fig. 1). These are so-called structureless or encrusting reefs [13]. However, differing morphologically coral communities of these reefs are quite similar to their bionomical composition and structures. In protected and inaccessible reefs are rich in biodiversity and high degree of up to 100% coverage of the substrate of living corals (Fig. 2) Only representatives of the genus Acropora, there are up 34 to 42 species, representing 82% of the total membership

3 94 Fig. 1 Reef cross section showing the distribution of common species of macrobenthos (A), the degree of substrate coverage by corals and relations between the colonies of different shape (B) off stony and corallogenous coasts. a) lagoon; b) inner reef flat; c) outer reef flat; d) slope; e) under slope platform; 1) degree of substrate coverage; II) branching colonies; III) encrusting colonies; IV) funnel form colonies; V) massive colonies; (1-48)-see Materials and Methods. The abscissa shows the offshore distance, m; the ordinate indicates the degree of substrate coverage, % along the left side and the number of colonies along the right side. F-structure and G-unstructured reefs. of these Scleractinian on reefs throughout Vietnam and a quarter of the total wealth of these corals on reefs Indo-Pacific [2, 14]. The abundance of these corals showed favorable terms on the reef, as it is known that acroporids among the first negatively react to environmental changes, primarily to anthropogenic pollution and eutrophication of the surrounding waters and therefore the first to die, there is no or very few and far between in the contaminated areas. The species diversity of macrobenthos in all transects was rather high and the number of species ranged from 312 to 457 (of which species of corals). The macrobenthos was dominated by 20 species: corals Sarcophyton trocheliophorum, Lobophytum pauciflorum, Junceella fragilis, Seriatopora hystrix, Montipora aequituberculata, Acropora palifera, A. F G nobilis, A. cytherea, Pachyseris rugosa, and Goniopora stokesi, mollusks Area ventricosa, Tridacna crocea, and Malleus malleus, echinoderms Metalia sternali sand Brissus latecarinatus, algae Dictyota divaricata, Sargassum polycystum, Padina australis, and Laurencia obtusa. However, each reef was usually dominated by only three to five species of macrobenthos. The research reefs, like other reefs of Vietnam, reveal clearly distinguished physiographic zones. These include both the well-known reef zones (lagoon, reef flat, etc.) and zones comparable with the former: algal-coral zone and zone of poly- and monospecific coral settlements [15-17]. The lagoon and reef flat extending into a well pronounced reef slope arise in the bays with sandy or corallogenous shores. On the grounds of geomorphology of the coastal line and the distribution of the corals and macrophytes together with the associated macro zoobenthos, the reefs of the surveyed area fall into three types: the reefs of rocky shores, the reefs of boulder-block shores, and the reefs of embayed sandy shores. The distribution of macrobenthos in all examined reefs reveals many similar features. In the first case, it is the vertical and lateral zonation in the exchange of facies and communities that depends significantly on the substrate nature. The general patterns of community development are similar, though their qualitative and quantitative compositions differ significantly. The number of common species ranges between 79 and 138. The degree of resemblance between different communities ranges within the limits of , and only in the communities of soft bottoms it is somewhat lower: from 10.2 to The species complexes of scleractinian reveal small differences in degrees of resemblance, though the highest values may differ from 29.6 to In mollusk taxocene, for 50% of the communities, the degree of resemblance does notdrop lower than 30.0 (Fig. 3). It is necessary to note here that the resemblance between neighboring different communities

4 95 (a) (b) Fig. 2 (c) (d) Coral community on different reefs: a-con Dao, b-hon Nai, c-bath Long Vi, d-lodd (Spratly Islands). Fig.3 Variations of the similarity of communities on the research reefs. m - macrophytes, a-common composition, b-soft bottom, c-reef slope, d-corals community, e-similarity community at various transects on reef Con Dao, f-community of soft corals of one and the same reef is higher than between the same communities on different separated reefs. A similar picture is revealed in communities of soft bottoms and reefs in other parts of Vietnam [18-20]. The presence in researcher reefs of lagoons with renewing thickets of macrophytes, with rather stable populations of echinoderms and herbivorous mollusks with a large number of juveniles allows us to judge that both the heterotrophic and autotrophic parts of the examined reefs are stable. A similar condition of reefs in the Red Sea was considered by Mergner [21] as the climax one. Most reefs in the area studied reveal a pronounced physiographic zonation, a high degree of species diversity and substrate coverage, mass development of spherical and tabular forms of coral colonies, and solid monospecific settlements of Acropora. This is characteristic of the climax condition of reefs [20, 22-26]. 4. Conclusions Stability of coral ecosystems of protected and laborious reefs, its exceptional biodiversity on most reefs provided them uninhabited, i.e. the lack of

5 96 human influence, and its great distance from the Mainland. Maritime continental ecosystem of the South China Sea can be dependent on the utilization of ecosystems such reefs resume resources larvae. The coral ecosystem of reefs Bath Long Vi, Hon Nai, Con Dao, and Lodd Islands can be seen as a "savings bank" where of corals, the commercially important invertebrate and fish are preserved from overfishing, and this is a constant flow of maggots to areas South China Sea depleted marine resources. The high species diversity of the reef community of protected and inaccessible reef sand its ecological status require special attention, and therefore recommendations were given to the Academy of Science and Technology of Vietnam regarding the creation of a protected such area reef for the purpose of conservation and restoration of the biological diversity of the South-China Seas a whole. Acknowledgment The authors express their gratitude tomy colleagues I. Budin, A. Goloseev, V. Brykov, N. Selin and Yu. Yakovlev for help with field studies. References [1] S. Ekman, Zoogeography of the sea, London, Sidgwick and Jackson, 1953, pp [2] Y.Ya. Latypov, Scleractinian corals and reefs of Vietnam as a part of the pacific reef ecosystem, Open Journal of Marine Science 1 (2011) [3] N.T. An, V.D. Son, P.M. Thu, N.H. Huan, Tracing sediment transport and bed regime in nha trang bay, Collection Marine Research Works 10 (2000) [4] D.S. Pavlov, A.V. Smurov, L.V. Iliyash, et al., Present-day status of coral reefs of nhatrang bay (Southern Vietnam) and possible reasons of the disturbance of scleractinian habitats, Biologia Morya 30(1) (2004) [5] D.L. Bryant, J.W. Burke, Mc. Manus, M. Spalding, Reefs at Risk, A Map Based Indicator of Threats to the World s Coral Reefs, World Resources Institute, Washington DC, [6] C.R. Wilkinson, Status of Coral Reefs of the World: 2000, Australian Institute of Marine Science, Townsville, [7] T.A. Gardner, I.M. Côté, J.A. Gill, A.Grant, A.R. Watkinson, Long-term region-wide declines in caribbean corals, Science 301 (5635) (2003) [8] W.F. Precht, A.W. Bruckner, R.B. Aronson, R.J. Bruckner. Endangered acroporid corals of the caribbean, Coral Reefs 21 (1) (2002) [9] J. Geister, The influence of wave exposure on the ecological zonation of caribbean reefs, in: Proceeding of 3 rd International Coral Reef Symposium, Miami l (1977) [10] Y. Loya, L. Slobodkin, The coral reef of Eilat (gulf of Eilat, Red Sea), Symp. Zoological Society of London 28 (1971) [11] T. Serensen, A method of establishing groups of equivalent amplitude in plant sociology based on the similarity of species content and its application to analysis of the vegetation of Danish common, Kongelige Danske Videnskabernes Selskab 1(5) (1948) 34. [12] S.A. Wainwrigh, Reef communities visited by the Israel South Red Sea expedition, 1962, Bulletin of Sea Fish Station Israel 38 (1965) [13] Y.Ya. Latypov, Community structure of scleractinian reefs in the Baitylong Archipelago (South China Sea), Asian Marine Biology 12 (1995) [14] J.E.N. Veron, Corals in Space and Time: The Biogeography and Evolution of the Scleractinia, Cornell University Press, New York, [15] Y.Ya. Latypov, Composition and distribution of scleractinia on the reefs of Fukhan Province (South Vietnam), Biol. Morya 6 (1982) (in Russian) [16] Y.Ya. Latypov, Coral communities of the Namsu Islands (Gulf of Siam, South China Sea), Marine Ecology Progress Series 29 (1986) [17] Y.Ya. Latypov, Communities of coral reefs of central Vietnam, Russian Journal of Marine Biology 27 (4) (2001) [18] Y.Ya. Latypov, Benthic communities of coral reefs of Tho Chu Island, Bay of Thailand, South China Sea, Biologia Morya 25 (3) (1999) [19] Y.Ya. Latypov, Benthic Communities of coral reefs of Con Dao Islands, South China Sea, Biologia Morya 5-6 (1993) [20] H. Mergner, Quantitative ekologische analyse eines rifflagunen areals bei agaba (Golf von Agaba, Rotes Meer), Helgolnder Wissenschaft Meeresuntersuch 32 (4) (1979) [21] R.W. Grigg, J.E. Maragos, Recolonization of corals on lava in Hawaii, Ecology 55 (1974) [22] J.H. Connell, Diversity in tropical rainforests and coral reefs, Science 199 (4335) (1978) [23] R.G. Pearson, Recovery and recolonization of coral reefs recovery and recolonization, Coral Reefs (1981) (4) [24] C.R. Sheppard, Coral population on reef slopes and their major control, Marine Ecology Progress Series 7 (1982)