Page 10 - IJMS-526-v3-2-for Dr. Jayachandran

International Journal of Marine Science 2013, Vol.3, No.4, 23-32
http://ijms.sophiapublisher.com
29
northwest. With decreasing depth, the number of large
colonies of corals markedly increased. Soft corals
Sinularia dura, Lobophytum sp., Sarcophyton sp.,
scleractinian Favites abdita, Isopora palifera,
Montipora venosa, Porites lobata, and Goniopora
stokesi predominated in terms of frequency. The coral
covering of substrate was 5%~7%. The reef slope
down to about 12 m depth covered with coral thickets
and large bioherms up to 4~5 m high (Figure 6). This
reef zone dominated by two to three species of
Sinularia, Lobophytum, and Sarcophyton (Figure 7),
Figure 7 Polyspecific settlement of various Alcyonarian on the
reef Bath Long Vi (depth 10 m)
Figure 8 Bioherm on the reef Bath Long Vi (depth 6 m)
massive colonies of Porites, plate-like and encrusting
Montipora, Pectinia, Pachyseris, plate-like and
digitate Acropora, and branching Pocillopora. The
macrophytes Turbinaria, Asparagopsis and Gracilaria
also encountered. The covering of substrate was up to
30%~40% for corals and 10%~20% for algae. Large
colonies of Porites provided the basis for bioherms
(Figure 8). Among other common inhabitants of the
reef were the starfishes A. planci, C. novaeguineae,
and L. laevigata, the sea urchin D. setosum , and
mollusks P. margaritifera , Pteria penguin, Tridacna
squamosa, Lambis lambis and Conus textile. With
decreasing depth to 8~10 m, the number of corals
increased and hence so did the coral cover up to
7%~10%. The most widespread on this part of the reef
slope were S. dura, Acropora humilis , M. venosa, P.
lobata, G. stokesi , Platygyra lamellina, Leptoria
phrygya , Lobophyllia hemprichii, Merulina ampliata
and the hydroid coral Millepora platyphylla (coral
cover 40%~60%). Individual bushes of macrophytes P.
australis, Turbinaria sp. and A. taxiformis, the sponge
P. testudinaria, the starfish L. laevigata , the sea urchin
E. diadema, and the holothurian H. atra were
encountered.
At a depth of 2~6 m, the upper reef slope with a
well-defined system of spurs and grooves (buttress
system) supports the highest species diversity of
scleractinian (more than 150 species). A community of
Acropora and Montipora occurred this depth.
Acropora cytherea , A. hyacinthus, A. formosa, A.
grandis, Montipora hispida, M. aequituberculata, M.
vietnamensis , Pocillopora verrucosa and Seriatopora
hystrix were dominant. As a rule, large colonies of
Acropora millepora , A. specifera and M. hispida (or M.
eaequituberculata) formed stacked aggregations that
covered 100% of the substrate over several tens of
square meters. In this zone, the calcareous algae
Poroliton sp. and Halimeda sp., the alcyonarian
Cladiella pachyclados, the scleractinian Acropora
robusta, A. humilis, A. monticulosa, I. palifera,
Pocillopora woodjonessi, S. hystrix and Galaxea
astreata, various poritids and faviids (5~7 species of
each), the hydroid M. platyphylla, macrophytes
Turbinaria, Gracilaria and Asparagopsis were
widespread. Along with them, the starfishes L.
laevigata, C. novaeguineae, the sea urchins D.
setosum, E. diadema, the holothurians H. atra, and the
individual mollusks T. squamosa, Trochus maculatus,
Cyprea arabica, and C. textile encountered.