Scleractinia: India
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Scleractinia
Introduction
Stony corals (Scleractinia) constitute an Order of the Phylum Coelenterata of class Zoantharia. Corals are exclusively marine with a calcareous exoskeleton in which the living part (polyp) exists. The mesenteris or septa are in multiples of six, hence called Hexacorallia. They are either colonial or solitary and sedentary in habit. Corals generally feed on zooplankton though, part of the nutritional requirements are met from the extracellular photosynthetic products of the symbiotic algae living in the tissue. Reproduction is by both sexual and asexual methods, colony formation takes place exclusively by asexual intra or extratentacular budding. Colonial forms are called hermatypic for they form the chief reef builders while the solitary corals are called ahermatypic. About 700 species of hermatypic corals are described in literature from the Indo¬Pacific Ocean but due to taxonomic problems and ecomorphological variations,1 it is still difficult to precisely classify many, into genetically well defmed species.
The classification adopted for Scleractinia (former Madreporaria) by the present taxonomists is that of Vaughan and Wells (1943) as modified by Wells (1956) (Treatise on Invertebrate Paleontology).
Scleractinia is divided into five Suborders with many families and subfamilies. Most of the families and subfamilies are known only in the fossil forms. The recent or extant stony corals belong to the following five suborders:
Suborder Astrocoeniinna: Colonial, hermatypic, with level or projecting corallites and 1 to 2 cycles (6 to 12) septa. The suborder includes common genera like Pocillopora, Acropora and Monlipora, which are common in our waters too. Suborder Fungiina: Solitary or colonial, with more than two cycles of septa; septa united by synapticulae. It includes genera like Fungia, Podabacia, Halomelra, all of which also occur in our waters. Massive chief reef builder Porites also belongs to this Suborder.
Suborder Dendrophylliina: Solitary or colonial, coenosteum perforate; Synapticulae absent. ihese are mostly ahermatypes but a few are hermatypes.Turbinaria, Dendrophyllia. Tubaslreaea etc. are important genera of this suborder.
Suborder Faviina: Colonial encrusting or massive. Corallites single or form meandering valleys. Septa dentate, basically laminar. Important genera are Plalygyra, Symphyllia. Favia, Favites. Leptastres, all of which are dominant reef builders of our waters.
Suborder Caryophylliina: Mostly solitary, rarely colonial, corallum cup shaped or turbinate, septa exsert, margins entire or granular. Pali present around the columella.
This group includes many deep water forms and are generally non-conspicuous on surface reefs. The genera like Caryophyllia. Trochocyathus, Paracyathus; Flabellum. etc. belong to this Suborder.
The modern taxonomic criteria for the classification of corals are generally based on the nature of skeleton. Polyps are rarely taken into consideration. the growth form such as colonial, or solitary; the shape such as massive, ramose, encrusting, foliaceous, turbinate, discoid or createriform are prime criteria. The number of septa and their teeth; nature and form of columella; ornamentation on the surface of the skeleton; nature of cocnostem as to solid or porous are all of importance in the identification of corals.
Corals form the most dominant benthic marine community in tropical waters. They are the chief agents in building mighty reefs o( different kinds. In India, we have well developed reefs in Gulf of Mannar and Palk Bay, Andaman and Nicobar Islands and Lakshadweep that includes fringing reefs and atolls. Asort of patchy reefs' on wave cut aberration of the top of tiny islands as in Pirotan, Paga and Boria are found in Gulf of Kutch. Corals do occur along the west coast of India from Malvan to Cape Comorin though, no well formed reef has not been so far reported.
The skeleton of corals contains mQre than 98% of pure calcium carbonate and form raw material in construction and industrial purposes. In Southern India, reef corals were mined for calcium carbide industry since three decades, causing the deterioration of the shallow reefs. The calcareous sand formed as a result of the bioerosion of the reefs also contains CaCDJ and was mined in Gulf of Kutch. Corals are also used a building blocks in several parts of the world inch,tding India and is still a source of lime. Reefs provide protection from sea erosion and is the most effective natural barrier to continental and island shores. Coral reefs have aesthetic value and are of tremendous importance to development of Tourism. Many reef associated organisms such as crustaceans and molluscs -not to speak of ornamental reefs fishes -are of immense value to mankind as food and curios. Of recent, reef organisms are found to con~in biochemical compounds that.are of yalue in the treatment of many human diseases.
The Marine pharmacology is a fast developing branch of science for which the living raw material is plenty on reefs. However, indiscriminate exploitation of our reefs for industrial purposes coupled with natural interferences have caused great damage to reefs especially in South-east India, Gulf of Kutch and Lakshadweep. It is an ecosystel1l that needs immediate attention for preservation and conservation of its living resources.
Historical Resume
Very little work on coral fauna of India was done prior to 1900 though Alcock recorded a few deep sea corals from the Andaman sea and Lakshadweep as early as 1893 based on the cruises of RIMS Investigator. The Cambridge University .Expedition under the leadership of Prof. Stanley Gardiner also visited Minicoy at the southend of the Lakshadweep archipelago and made a detailed study of the reefs and reef corals. Brook, (1893) incorporated some species of Acropora from Rameswaram in his Catalogue ofthe Madreporarian corals in British Museum (Nat. Hist) based on the collection of Foote (1890) and Thurston (1895). Gardiner (1904, 1905) described many corals from Minicoy.
However, many of the specific names used by him were subsequently synonymised or emended. Gardiner op cit dealt with only Faviina and Fungiina of Minicoy and the rest still remains to be reported. Subsequently, Matthai (1914, 1928) described and revised many corals from Lakshadweep that were described by Gardiner. He also (Matthai, 1924) listed the Fungiina and Faviina from the Indian Museum Calcutta that includes materials from Strait of Malac~a and Andaman and Nicobar Islands. Gravely (1927) listed a few corals from Krusadai Island in Gulf of Mannar.
The presence of Acropora, Pocillopora. Monlipora, Porites, Fungia and Turbinaria were noticed by Sewell on the reefs of Nicobar in 1922, but no efforts were made to list them on species level. Form the Gulf of Kutch, Gideon'et ai, 1957, recorded four genera of corals. In spite of all the above' works, the reef building corals of our waters largely remained unknown till the late sixties of this century.
Of recent years a large number of papers on taxonomy, ecology and resources of our reefs have emerged in• many leading publications as a result of painstaking work of Indian and foreign scientists. Nearly a hundred papers on reefs of India including monographs were published since 1968. Pillai and coworkers in a series of papers described the corals of Gulf of Mannar and Palk Bay detailed taxonomic analysis of the fauna from this area has been made in 1986. He has also dealt with the ecological interferences in our reef system. The coral fauna of the Nicobar Islands was fully described and amply illustrated in a monographic work by Scheer and Pillai (1974) which is mainly based on the•collections of the 2nd Xarifa Expedition, West Germany. Pillai (1963) described some reefs of Andaman and listed the coral fauna.
The coral fauna of Lakshadweep was studied by Pillai from 1967 and has check listed the fauna. Subsequently Pillai and Jasmine described and figured all the known species of corals from Lakshadweep (1980). The cornl fauna of Gulf of Kutch was described by Pillai and Patel for the fust time (1988). The coral fonnation and coral fauna from the south west coast of India from Trivandrum to Cape Comorin was also studied by Pillai and Jasmine and a report is under preparation.
The major areas of reefs so far covered for taxonomic and ecological studies of our reefs include Gulf of Mannar and Palko Bay from Tuticorin to Rameswaram Island. Almost all the atolls and islands of Lakshadweep have been reported by CMFRI. Corals of Gulf of Kutch from Port Okha to Pirotan Island and"some areas of Middle Andamans (The Wandoor Marine National Park) and Nicobars have been studied. Still vast areas of Andaman and Nicobar Islands need study, though Rcddiah (1977) gave some description of the reefs of Andaman and Nicobar Islands. The major aspects of reef studies so far covered by various workers in the last 25 years or so are summarised as follows.
Morphology of reefs and distribution of reef building and reef dwelling organisms (S.E. India, Gulf of Kutch, Lakshadwcep).
Taxonomic studies on corals (S.E. India, Andaman and Nicobar Islands, Gulf of Kutch, Lakshadweep and south west coast of India).
Studies on the anthropogenic and natural impact on reef environs (S.E. India, Lakshadweep and Andamans).
The Coral Fauna or India
A total of 199 species of scleractinian corals from India's territorial waters is hitherto recorded from the major coral growing areaS of Gulf of Mannar, Gulf of Kutch, Andainan and Nicobar Islands and Lakshadweep. Deep water forms still await investigation. It is possible that a few more species await de~tion from our waters especially from the Andaman area
Estimation of Taxa
Phylum COELENTERATA Frey and Leuckart, 1847 Subphylum CN/DARIA Hatschek, 1888 Class ANTJ-IOZOA Ehrenberg, 1834 Subclass ZOANTIIARIA Ehrenberg, 1834 Order SCLERACTINIA Bourne, 1900
The Indian coral fauna includes genera and species of all the five suborders of the order Scleractinia. The suborder Astrocoennina is represented by the families Thamnasterridae with a single genus Psammocora (4 known species). Family Pocilloporidae is represented by 4 genera of which Pocillopora is the commonest genus in all reef habitats. At least seven species of Pocillopora are recorded from India. Family Acroporidae is perhaps the richest in species number all over 'the Indo-Pacific, the common genera being Acropora. Montipora and Astreopora. At least 31 species ofAcropora occur in our waters. M ontipora of different growth forms is represented by 20 species and Astreopora by 2 known species.
The Suborder Fungiina has two superfamilies in Indian waters viz. Agariciicae and Fungiicae. Pavona. Pachyseris. Leptoseris, Gardineroseris are common genera. A total of 15 species of Agariciicae of the family Agariicidae are known. The genus Coeloseris is known only from Andaman waters with a single species. Family Siderastreidae has three genera viz. Siderastrea, Pseudosiderastrea and Coscinarea each with a single species. The members of this family are not very common on our reefs. Superfamily Fungiicae includes the solitary Fungia and allied genera, and the major reef builder Porites and Goniopora. Family Fingiidae has Cycloseris (5 species), Fungia (8 species), Fungiacyathus (1 species), Herpolitha (1 species), PolyphyUia (1 sp.) and Podabacia (1 species).
Fungids are common in Andamans and Lakshadwecp but very rare along the main land coast. The superfamily Poriticae of the suborder Fungiina is represented by the family Poritidae. The genus Porites with 10 species hitherto recorded is the most abundant coral on our reefs and is mainly exploited for construction work and industrial use. The other genus Goniopora is also common and has about 5 species in our waters. A third genus of this family is Alveopora and is extremely rare on 'surface reefs.
The suborder Faviina. is represented by families Faviidae, Trachyphyllidae, Rhizangiidae, Ocu1.inidae. Merulinidae, Mussidae and Pcctinidae. Favia (6 species), F avites (6 species), Goniaslrea (2 species), Platygyra (2 species) and Hydnophora (2 species) are the common genera of the family Faviidae.
They constitute important massive reef builders. Leptastrea and Cyphastrea are also present in all the reef environs. Another genus of Faviidae is Echinopora which cut large foliaceous platforms and is very common in Gulf of Mannar though not common in other parts of India. A total of 30 species of Faviidae is hitherto recorded. The families Trachyphylliidae, Rhizangiidae, Oculinidae, Merulinidae, Mussidae and Pectinidae are not abundantly represented in our waters.
The Suborder Caryophylliina has only two families, Caryophylliidae an Flabellidae. The former has 10 genera, mostly deep water and solitary. Flabellidae is represented by Flabellum (the cup coral) and Placblrochus, both of which are ahermatypcs.
The fifth Suborder of Scleractinia has a single family viz. Dendrophyllidae. Mostly solitary but Turbinaria and Dendropizyllia are colonial. A total of 7 genera and 18 species are known from our waters.
Current Studies
Scientists of Central Marine Fisheries Research Institute, Cochin are studying ecology and human interferences on our reef systems in Lnkshadweep and Andamans. A recent survey in Lakshadweep was made to select suitable islands as biosphere reserves with a view to protecting the endangered reefs. The Central Drug Research Institute, Lucknow and some Universities are screening reef corals and reef associated organisms for biomedical compounds. The Scientists of National Institute of Oceanography reef systems in Lakshadweep. INTACH is having a project to assess the environmental damage on Andaman reefs. The coral fauna 'of the southwest coast of India is being studied in Central Marine Fisheries Research Inslitute, Cochin.
Expertise India
M. Bapuji, Regional Research Laboratory, CSIR, Bhubaneswar, Orissa, 751013, [Biomedical compounds of reef organisms].
M.N. Srivastava, Botany Division, Central Drug Research Institute, Chattar Manzil, P.B.No. 173, Lucknow -226001. [Biomedical research ofreef and other marine organisms].
Pillai, C.M.F.R. Institute, Cochin -31. [Taxonomy of corals. Anthropogenic and natural impact on reefs and reef resources. Conservation of ecosystem]. Jasmine, ClvlFR Research Centre, Vizhinjam, Via Trivandrum. [Taxonomy of corals].
M.I. Patel, Gujarat State Fisheries Aquatic Science Station, Sikka, Gujarat. [Taxonomy and ecology of corals of Gulf of Kutch].
M.V.M. Wafer, National Institute of Oceanography, Goa. [Productivity and nutrition of coral reefs].
Abroad
D.R. Stoddart, Dept. of Geography, University of California, Berkeley, CA. 94720, USA. [Geomorphology, interference and morphology of reefs].
G.J. Bakus, Dept. of Biological Sciences, University of California, Berkeley. CA., USA, [Biomedical research on reef organisma. Reef ecology J.
George Scheer, Dept. of Zoology (Retired), Hessisches Landes Museum,. 61 D. Darmstadt. West Gennany. [Coral sociology and taxonomy, of corals].
H. Zibrowius, Station Marine d'Endoume Rue Batterie des Lions Marselle. France. 13007. [Symbiosis, ecology and taxonomy of deepwater and solitary corals].
H. Schumacher, Universitat G.H. Essen, Postfach. 103764 D. 4300 Essen. West Germany. [Ecology ofrccfs and resources].
Brian, R. Rosen, Dept. of Palaeontology, British Museum (Nat. Hist), Cromwell Road, London. U.K. [Taxonomy of corals].
Veron, Australian Institute of Marine Science Townville. Qld. 4810. Australia, [Taxonomy of corals].
Pichon, Department of Biological Sciences, James Cook University, James Cook Univ. Post Qld. 4811. Australia. [Taxonomy of corals and ecology of reefsl.
D.H.H. Khulman, Natural History Museum of Humboldt Univ., Invaliden Streasse. 43 Berlin. 1040. [Rccf studies on ecology and taxonomy of organisms].
D.W. Kinsey, Great Barrier Reef Marine Park Authority, Towsville. Qld. Australia. [Ecological stress and conservation of reefs].
Glynn, Division of Biology Roscnstcil School of Marine and Atmospheric Science, Univ. Miami, 4600 Florida. 331.49. U.S.A. [Pathology of reef corals, Biology of corals. etc].
Yalnazato, Dept. of Biology, Univ. Ryukyus. Nishihara Okinawa. Japan. [Pollution of coral environs].
Lock M. Chou, Dept. of Zoology, National University of Singapore Kent Bridge, Singapore. 0511. [Reef ecology].
Selected Rererences
Brook G.H.M. Bernard & G. Mattahi. 1893-1927. Catalogue of the Madreporian corals in the British Museum (Nat. Hist). Vol. 1. Madreporaria Vol. 2. Genus. Turbinaria and Astraeopora. Vol. 3. Montipora Vol. 4. Genus Goniopora Vol. 5. Vol. 6. Porites and
Vol. 7. Colonial Astraeidae.
Endean, R (Ed). 1973. Biology and geology ofcoral reefs Vols.4, Academic Press.
James, P.S.B.R. &Pillai C.S.G. 1989. Environmental damage and its consequence in
Lakshildweep. Bull. cent. mar. Fish. Res.lnst. 43 : 179-195. Pillai, C.S.G. 1983. The coral environs of Andaman and Nicobar Islands. Bull. cent. Mar. Fish. Res. Inst., 34 : 33-43. Pillai, C.S.G. 1986. Recent corals from the southeast coast of India. In Recent Advances in Marine .Biology. Today &Tomorrow publishers" New Delhi.' 107-201. Pillai, C.S.G. &Jasmine, S. 1989. The coral fauna of Lalcshadweep. Bull. cent. ¥ar. Fish Res. Inst., 43 : 179-195. Pillai, C.S.G. &.Patel~ M.I. 1988. The coral fauna of Gulf of Kutch. J. Mar. bioi. Ass. India, 30
- 54-64, pIs. 13. Pillai, C.S.G. &Scheer, G. 1976. Recent corals from the Maldives. Zoologica 126 :
1-83. Scheer, O. &Pi1lai, C.S.G. 1974. Report on the scleractinia of Nicob~ Islands: Zoologica 22:
1-75. Scheer, G. &Pillai, C.S.G. 1983. Report on the stony corals of Red Sea. Zoologica, 133 : 1¬ 197.
Veron, J.E.N. et ale 1976 to 80. Scleractinia of eastern Australia in 5 parts. Monogr. sere Australian Inst. Mar. science, 1-5.
