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SPECIES COMPOSITION AND STRUCTURE OF THE PROTECTED REEF IN THE CAM RANH BAY
N-I- Selin'. Yu.Ya. Latypov', M.L Bui^ L.Q.Pham' I. A.V. Zhirmunsky Inslitute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041 Russia 2. Nha Trang Institute of Technology Research and Application, Vietnam Academy of Science and Technology 3. Institute of Natural Products Chemistry- Hanoi, Vietnam Academy of Science and Technology For the last decades global climate changes, industrial development and grovrth of population in coastal cities led to changes of coral reef ecosystem. These changes are often negative. They appear as reef degradation. In 2010 we found the coral reef Sannest Islands, located not far from Cam Ranh city in East Vietnam Sea. We were impressed by coral species and other associated organisms abundance of the reef, which made it different from other nearly islands. That's why we studied the species composition and structure of this reef adjoining to the biggest island - island Hon Noi.
In our work scuba technique and standard hydrobiological methods of frames and transects were used. We took pictures of underwater landscapes and reef inhabitants as well (more than 900 pictures).
282 species of macrophytes and invertebrate were found on the reef of the Hon Noi Island. 169 species were scleractinians. The following 27 species dominated:
macrophytes Padina australis, Halophyllia ovalis, alcyonarian Sinularia dura H Sarcophylon trocheliofonim, scleractinian Acropora microphthalma, A.nobilis, A.valenciennesi, A.venveiy, Montipora aequiluberculata, M.hispida, M.gricea, Hydnophora rigida, Porites cylindrica, P.rus, Platygyra daedalia, Leptoria phrigia, Favia speciosa and Favia sp., mollusks Tridacna maxima, T.crocea,
T.squamosa, Lambis chiragra, echinodermata Diadema setosum, Hololhuria aira, Siihopus chloronalus, Linckia laevigata and Ohpiocoma nigra. Monospecific settlements of up to 100m" formed Acropora microphthalma and A. nobilis. These two species together with H. rigida, M. aequiluberculata and M. gricea formed dense settlements, totally covering big areas of the bottom. In toial the coral species diversity of scleractinians was 27.4.
Zone of Acropora microphthalma -I- Hydnophora rigida was located at a depth of 0.5-1.5m. It completely covered 20-40m of the bottom from the shoreline.
Acropora cylherea, A.humilis, Montipora gricea, M.hispida and M.vielnamensis were also widespread in this zone and Seriatopora hyslrix, Stylophorapistilala and Porites lobata could be found as well. Mats of algae Chnoospora implexa were
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Fig.l. Zone of Acropora nobilis
located between branches of Acropora. Because of dominating of just two species (A.microphthalma and Hrigida) coral species diversity was very low (4.3).
After zone of Acropora microphthalma + Hydnophora rigida there was more rich with coral species zone of Acropora nobilis (Fig.l), which covered 25-30m and reached 2.5-3m in depth. Here we could find big colonies of A.nobilis, A.spicifera, A.hyacintus, M.aequituberculata, M.gricea, M.vielnamensis, Hrigida, Porites nigrescens, P.cylindrica,
Pocillopora eudouxi, P.woodjonesi, as well as mollusks Lambis chiragra, L.scorpius, Trochus nilolicus T.maculatus, and echinoderms Linckia laevigata, Hololhuria atra, Stichopus chloronalus.
Coral species diversity was 9.7.
At a depth of 3m zone of polyspecific settlements began (Fig. 2). It covered 20-30m up to 6m in depth.
There were 73.5% of total scleractinian numbers in this zone. Coral species diversity was 20.7. Corals of more than 30 genera were found there. A.cytherea, A.monticulosa, A.humilis, Porites lobata, P.rus, P.cylindrica, Pocillopora eydouxi, P.verrucosa, Platygyra daedalia, P.lamellina, Galaxea fascicularis, Merulina ampliata, Lobophyllia hemprihii and Symphyllia recta, hidroidea Millepora dichotoma and M.platyphyla were the most widespread.
Fungia scutaria, F.scruposa, F.granulosa and Polyphyllia talpina were sporadical. Substrate covering by corals was 30-75%. Often found associated species were Tridacna maxima (0.2 spc./m^), Lambis hiragra (0.1 spc.W), Trochus nilolicus, T.maculatus (0.2 s p c W ) , Diadema selosum (up to 5 spc/m^), Stichopus chloronalus (0.2
s p c / m ) , Synapta maculala, Linckia laevigata, Acanlhaster plancL
Around 70-lOOm from the shoreline there was a fore reef platform. About 30 species of scleractinians (18.9%) inhabited the area. Coral species diversity was 7.5. Few species such as G.fascicularis, P.lamellina, Goniastrea pectinata, Favia maritima, Porites cylindrica, P.lobata, Montipora verrucosa, Sinularia polydactila, Lobophytum pauciflorum, M.platyphyla, M.dichotoma and Heliopora coerulea lived on coralogenic substrate. Substrate covering by corals didn't exceed 5-7%. In associated macrofauna D.selosum was dominating (up to 7- 10 spc./m), Culcita novaeguineae, Linckia laevigata and spongia Callyspongia sp. were sporadical. On the- sandy bottom there were gastropods Strombus luhuanus (up to 14 spc./m^); bivalve Vaslicardium,
Fig. 2. Zone of polyspecific settlements
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Fulvia, Laevicardium, Malleus malleus (up to 0.5 spc./m^) and Isognomon isognomum could be recorded rarely.
The reef of Hon Noi island was similar to other reefs of South Vietnam in morphology, degree of coral development, their quality and quantity composition. 58-69% out of 169 scleractinian species were the same with reefs of Nha Trang bay. Con Dao Islands, Siam and Tonkin Gulf (Latypov, Long, 2010).
For example, one genus Acropora included 34 species, which made 40% from the total scleractinian on the reefs of whole Vietnam and 14 of total coral richness on the Indo-Pacific reefs (Latypov, Long, 2010). Abundance of these corals indicated good conditions on the reef, because, as it's known, Acropora reacts quickly on the environment pollution: dies, absents or exists scantily in the polluted areas (Latypov, 2006). Their abundance shows climax state of the reef
The results of hydrobiological researches of Vietnam continental and island reefs during last years showed their biological degradation, mostly caused by anthropogenic press (Pavlov et al., 2004; Latypov, 2006). Protection and minimization of anthropogenic influence on some Vietnam reefs (Mun Islands, Bach Long Vi and Con Dao) improved their ecological condition. For the last 5 years species diversity here didn't decrease and exceeded the same on the nearly unprotected reefs (Latypov, 2006; Latypov, Selin, 2008). The results of researches near Hon Noi island (being under protection of Sannest Company) showed visually positive influence of protecting measures on the wellbeing of the reef
Acknowledgment:
The work was made within Open Russian-Vietnamese Laboratory of Biochemistry of A.V. Zhirmunsky Institute of Marine Biology Far East Division Russian Academy of Sciences (IBM, Vladivostok) and Nha Trang Institute of Technology Research and Application Vietnam (NITRA, VAST Nha Trang) and Institute of natural Products Chemistry -Hanoi (INPC-VAST), We are sincerely grateful also for finacial support by Project No.l/I9/47 "Vietnam-Russia collaboration on marine biologycally active compounds and biodiversity of Vietnam"
BIOLIOGRAPHY
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2. Latypov, Yu.Ya., Selin, N.L Coral communities of barrier reefs of Vietnam // Russian Journal of Marine Biology, 2008, vol. 34, no. 3, pp. 143-150.
3. Latypov, Yu. Ya., Long. P.Q. The common hard corals of Vietnam. Hanoi. 2010. 281 p.
4. Pavlov, D.S., Smurov, A.V., Ilyash, L. Ketal. CurrentStateof Coral Reefs in Nha Trang Bay (South Vietnam) and Probable Causes of Adverse Habitat of Scleractinians // Biol.
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