Crassostrea madrasensis   (Preston)  (Oyster)
Organism information awaits expert curation
Class: Bivalvia

Image copyrights: FAO

The shell is moderately thick and externally scaly and with the inner surface of the valves porcellanous and whitish. The adductor muscle scar is of a deep purple color; the hinge is narrow and elevated. Shell straight, shape irregular, covered by numerous foliaceous laminae, left valve deep, right one slightly concave, hinge narrow and elongated, adductor scar sub-central, reniform and dark purple in colour, inner surface of valves white, glosssy and smooth, purplish black colouration on the inner margin of the valves.
The right and the left mantle lobes of the oyster enclose a large mantle cavity which is divisible into a lower inhalent chamber and an upper exhalent chamber. In the inhalent chamber are two pairs of gills one each on the right and left sides extending forwards upto the two labial palps between which the mouth is present. In about the middle of the body is the adductor which runs across the two valves of the shell. It consists of a large anterior translucent portion formed of striated muscle fibres, which brings about rapid contraction that can close the shell quickly and a narrow posterior portion composed of smooth muscle fibres, which functions as a catch muscle to fix the valves in a particular position either partially or fully open. In front of the posterior adductor is the pericardium enclosing the heart with two auricles and a ventricle. The digestive system consists of a narrow oesophagus leading from the mouth, a spacious stomach closely pressed against the ramifications of the digestive gland of either side, a slightly twisted midgut with a style sac in the oral process, a long intestine partly within the oral process and partly encircling the stomach and a rectum opening into the exhalent chamber by the anus located on the dorsal side of the adductor muscle. Much branched vesicles with connective passages at the junction of the mantle with the body constitute the kidneys. The gonads of the oyster are creamy white, highly branched, tubular follicles lying below the body epithelium around the visceral organs.The follicles of the two sides almost fuse at the hinge region and are absent below the oesophagus and around the pericardium. The gonoducts of the two sides open into two separate urino-genital clefts near the adductor muscle. In fully ripe females the ramifications of the follicle tubules are clearly discernible and this is not the case in ripe males. In partly spawned oysters of both sexes the upper portion of the gonad is flabby and there is accumulation of watery fluid, while lower below there are ripe germ cells within the follicles. The amount of watery fluid in the gonads depends on the extent of spawning. Generally the fully spent female oyster presents a more flabby appearance than a fully spawned male.

The oyster is normally unisexual, but change of sex has been observed with a fair number of individuals in a transitional hermaphroditic phase.

The species has a wide range of tolerance to variations in salinity of waters in the environment.

Synonym (s)
Ostrea cucullata Hornell, 1910
Ostrea virginica Annandale & Kemp, 1916
Ostrea virginiana Hornell, 1922b
Ostrea virginiana var. madrasensis Moses, 1928
Ostrea arakanensis Winckworth, 1931
Ostrea madrasensis Preston, 1916
Ostrea madrasensis Awati and Rai, 1931
Ostrea madrasensis Gravely, 1941
Ostrea madrasensis Paul, 1942
Ostrea madrasensis Rao, 1951
Ostrea ( Crassostrea) madrasensis Rao, 1956
Ostrea madrasensis Satyamurthi, 1956
Crassostrea madrasensis Rao, 1958

Common Name (s)
• Estuarine Oyster (English)
• Ali (Tamil)
• Kalungu (Tamil)
• Patti (Tamil)
• Muringa (Malayalam)
• Muru (Malayalam)
• East Coast Edible Oyster
Economic Importance and Threats
Importance:  Commercial
Possess high antiviral activity)

Habitat:  Reef Associated, Demersal, Estuarine, Sandy, Coastal
Trophic Level:  Consumer
Prey:  Diatoms (Biddulphia, Rhizosolenia, Chaetocersa and Coscinodiscus) and detritus


• Orissa, Mahanadi Estuary INDIA
• Tamil Nadu, Ennur Backwaters INDIA
• Tamil Nadu, Pulicat Lake INDIA
• Tamil Nadu, Thondi INDIA (Record: 06/2005-05/2006)
• Karnataka, Netrani Island (Lat: 14.01) (Long: 74.32) INDIA (Record: 08/05/2006) (Depth: -12 mts)
• East Coast, Coromandel, Pulicat Lake INDIA (Record: 1997-1998)
• Kerala, Vypin Island INDIA
• Tamil Nadu, Pichavaram (Lat: 11.42) (Long: 79.79) INDIA
• Tamil Nadu, Pichavaram INDIA
• Tamil Nadu, Vellar Estuary (Lat: 11.48) (Long: 79.76) INDIA
• Pondicherry, Pondicherry mangrove (Lat: 11.76) (Long: 79.82) INDIA (Record: 01/2002-12/2003)
• Pondicherry, Pondicherry mangrove (Lat: 11.89) (Long: 79.8) INDIA (Record: 01/2002-12/2003)
• Kerala, Vembanad Kol INDIA
• Kerala, Tellicherry INDIA
• Kerala, Beypore INDIA
• Kerala, Kochi Harbour INDIA
• Kerala, Azhikode INDIA
• Kerala, Vembanad Lake INDIA
• Tamil Nadu, Cuddalore INDIA
• Tamil Nadu, Covelong INDIA
• Tamil Nadu, Chennai Harbour INDIA
• Tamil Nadu, Ennur INDIA
• Andhra Pradesh, Godavari Delta INDIA
• Andhra Pradesh, Krishna Delta INDIA
• Andhra Pradesh, Visakhapatnam INDIA
• Orissa, Chilika Lake INDIA
• Pondicherry, Pondicherry mangrove (Lat: 79.8) (Long: 11.88) INDIA (Record: 01/2009)
• Pondicherry, Pondicherry mangrove (Lat: 79.81) (Long: 11.76) INDIA (Record: 01/2009)
• Tamil Nadu, Arukkattuthurai (Lat: 10.39) (Long: 79.86) INDIA (Record: 09/2007-08/2008)
• Tamil Nadu, Kodikkarai (Lat: 10.3) (Long: 79.85) INDIA (Record: 09/2007-08/2008)
• Tamil Nadu, Mallipattinam (Lat: 10.27) (Long: 79.32) INDIA (Record: 09/2007-08/2008)
• Tamil Nadu, Manalmelkudi (Lat: 10.42) (Long: 79.31) INDIA (Record: 09/2007-08/2008)
• Tamil Nadu, Adirampattinam (Lat: 9.95) (Long: 79.18) INDIA (Record: 09/2007-08/2008)
• Tamil Nadu, Chennai INDIA
• Tamil Nadu, Thondi INDIA (Record: 07/2005-06/2006)
• Andaman and Nicobar Islands, Port Blair INDIA
• Kerala INDIA
• Tamil Nadu, Pulicat INDIA
• Tamil Nadu, Athankarai INDIA
• Tamil Nadu, Mandapam, Kanchanagudi INDIA
• Tamil Nadu, Karangadu Mangroves (Lat: 9.64) (Long: 78.94) INDIA (Record: 02/2010) (Depth: 1-2 mts)
• Tamil Nadu, Karangadu Mangroves (Lat: 9.64) (Long: 78.96) INDIA (Record: 02/2010) (Depth: 1-2 mts)
• Andhra Pradesh, Gokulapalle INDIA
• Orissa, Sonepur INDIA
• Tamil Nadu, Kalpakkam INDIA (Record: 1987-1988)
• Tamil Nadu, Edaiyur Backwaters (Lat: 12.56) (Long: 80.18) INDIA (Record: 04/1988-03/1989)
• Andaman and Nicobar Islands INDIA

Literature Source(s)
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Bal, DV and Rao, KV (1984) Marine fisheries Tata McGraw-Hill Publishing Company Limited 470 pp Available at - NIO, Goa
  • Sealifebase Available at -
  • Serebiah, JS; Stella, C and Kadhar, AA (2008) Assessment of benthos in the subtidal area of Thondi (Palk Bay), southeast Tamilnadu- GIS based explication Proceedings of the national symposium on marine and coastal ecosystems 27-29, August 2007 Seaweed Research and Utilisation Seaweed Research and Utilisation Association, Marine Fisheries- 623 520, Tamilnadu, India 30 279-296 Available at - NIO, Goa
  • Lovatelli, A. (1990) Regional seafarming resources Atlas Available at -
  • Zacharia, PU; Krishnakumar, PK; Dineshbabu, AP; Vijayakumaran, K; Rohit, P; Thomas, S; Sasikumar, G; Kaladharan, P; Durgekar, RN and Mohamed, KS (2008) Species assemblage in the coral reef ecosystem of Netrani Island off Karnataka along the southwest coast of India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin, India 50(1) 87-97 Available at - NIO, Goa
  • Raj, PJS, Tilak, JL and Kalaimani, G (2002) Experiments in restoration of benthic biodiversity in Pulicat Lake, south India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin 44(1 & 2) 37-45 Available at - NIO, Goa
  • Ittoop, G; George, KC, George, RM; Sobhana, KS; Sanil, NK and Nisha, PC (2005) Effect of salinity on the hemocyte profile and phagocytosis in the Indian edible oyster, Crassostrea madrasensis (Preston) Journal of the Marine Biological Association of India The Marine Biological Association of India 47(1) 31-35 Available at - NIO, Goa
  • Prasad, MBK and Ramanathan, AL (2009) Organic matter characterization in a tropical estuarine-mangrove ecosystem of India: Preliminary assessment by using stable isotopes and lignin phenols Estuarine, Coastal and Shelf Science Elsevier 1-8 Available at -
  • Chatterji, A., Ansari, ZA., Ingole, BS., Bichurina, MA., Sovetova, M., Boikov, YA. (2002) Indian marine bivalves: Potential source of antiviral drugs Current Science 82(10) 1279-1282 Available at - NIO, Goa
  • Balasubramanyan, K (1994) Micro-invertebrate benthic fauna of Pichavaram mangroves Conservation of mangrove forest genetic resources: A training manual Available at -
  • Saravanan, KR; Ilangovan, K and Khan, AB (2008) Floristic and macro faunal diversity of Pondicherry mangroves, South India Tropical Ecology International Association for Ecology, Cambridge University Press 49(1) 91-94 Available at -
  • James, EJ (2005) Management of river basins in relation to coastal wetlands: case studies from Indian subcontinent kerala environment congress 2005 Centre for environment and development 21-47 Available at - NIO, Goa
  • Alagarswami, K and Narasimham, KA (1973) Clam, cockle and oyster resources of the indian coasts Living resources of the seas around India CMFRI, Cochin 648-658 Available at -
  • Kesavan, K; Babu, A; Ravi, V and Rajagopal, S (2009) A checklist of malacofauna from Pondicherry mangroves International Journal of the Bioflux Society Centre of Advanced Study in Marine Biology 31-36 Available at -
  • Kesavan, K; Palpandi, C and Shanmugam, A (2009) A checklist of malacofauna of the Vellar estuarine mangroves, India Journal of Threatened Taxa Wildlife Information Liaison Development Society 1(7) 382-384 Available at -
  • Varadharajan, D; Soundarapandian, P; Gunalan, B and Babu, R (2010) Seasonal abundance of macro benthic composition and diversity along the south east coast of India European Journal of Applied Sciences IDOSI Publications 2 (1) 1-5 Available at -
  • Raj, PJS (2006) Macro fauna of Pulicat lake NBA bulletin No.6 NBA Available at -
  • Anbuchezhian, R; Ravichandran, S; Serebiah, JS and Nobi, EP (2010) Geographic information system based assessment of benthic macrofauna in Thondi coastal area, south east coast of India World Journal of Zoology International Digital Organization for Scientific Information 5 (3) 172-182 Available at -
  • Rao, KS (1974) Edible bivalves; mussels and oysters The commercial molluscs of India Bulletin Of Central Marine Fisheries Research Institute CMFRI, Cochin 25 4-39 Available at -
  • Sundaram, KS; Sarvesan, R; Mohamed, KH and Shanbhogue, SL (1969) Catalogue of molluscs, prawns, stomatopods and marine algae in the reference collections of the central marine fisheries research institute Bulletin Of Central Marine Fisheries Research Institute CMFRI, Cochin 9 1-52 Available at -
  • Venkatesan, V; Kalidas, C; Zacharia, PU and Rajagopal, S (2010) Distribution of molluscan fauna in the Karangad estuarine mangroves, south east coast of India Advances in Environmental Sciences - International Journal of the Bioflux Society Bioflux 2 (2) 113-119 Available at -
  • Jones, S (1969) The molluscan fishery resources of India Proceedings of the Symposium on Mollusca CMFRI 906-918 Available at -
  • Sasikumar, N; Rajagopal, S and Nair, KVK (1989) Seasonal and vertical distribution of macrofoulants in Kalpakkam coastal waters Indian Journal of Marine Sciences Scientific Publishers 18(4) 270-275 Available at - NIO, Goa
  • Rajagopal, S; Azariah, J and Nair, KVK (1990) Ecology of fouling organisms in Edaiyur backwaters, Kalpakkam Mahasagar- Bulletin of the National Institute of Oceanography NIO, Goa 23 (1) 29-41 Available at -
  • Rao, GC (1991) Distribution of plants and animals on the rocky sea shores of Andaman and Nicobar Islands Journal of the Andaman Science Association Andaman Science Association, Port Blair 7(2) 30-42 Available at - NIO, Goa
  • Pillai, PKM and Augustine, SK (2000) A code list of common marine living resources of the Indian seas CMFRI Special Publication No.12 CMFRI 1-115 Available at -

Page last updated on:2011-12-19

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