ENVIS Centre, Ministry of Environment & Forest, Govt. of India

Printed Date: Tuesday, August 4, 2020

Gulf of Mannar

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Gulf of Mannar
     
Name of the area
:
Gulf of Mannar
Place :
:
Between Thoothukudi and Dhanuskodi
State :
:
Tamilnadu
Latitude :
:
8°47’N and 9°15’N
Longitude :
:
78°12 ’E and 79°14 ’E
     
     
Key Physical Characters
     
Total reef area
:
94.3 sq km
Depth
:
2 to 9mts
Transparency :
:
1 to 3m
Water temperature:
:
25° to 30°c
     
     
Chemical Characters
     
pH :
:
7.6 to 8.4
Salinity :
:
32.4 to 32.8ppt
Dissolved Oxygen :
:
4.5 to 4.9
     
     
Major Flora and Fauna
     
Benthic Fauna :
:
Shrimp, lobster, crabs, seacucumber, mollusk, gastropods, polychaetes etc.,
    Name of the species - IUCN status
Sponges
   
   
Heteronema erecta - Not avilabale 
   
Dentriela cactus - Not availabale
   
Sigmadocia fibulata - Not Available
   
Sigmadocia pumila - Not evaluated
   
Echinodictyum clathrat um -Not evaluated
   
Microciona aceratoobtusa - Not available
   
Optulitaspongia rimosa - Threatened
   
Phycopsis sp. - Not Evaluated
   
Spirastrella coccinea -Not evaluated
   
Cliona celiba - Not available
   
Cliona orientalis - Not available
   
(Source: Asir Ramesh Ph.D Thesis - 1996)
     
Polychaeta
   
   
Syllis sp.
   
Nereis sp.
   
Perinereis cultrifera
   
Eseudo rereis gallapogensis
   
Eunice atra atra
   
Eunice antennae
   
Salbellaria Pectinata
   
Sabellaria spinulosa
   
Serpula vermiularisis
   
Hydroides minax
   
(Source: Asir Ramesh Ph.D Thesis – 1996)
     
Phytoplankton
 
126 species of phytoplankton were reported (Kannan, 1996).
     
   
Diatoms : 97 species (33 genera)
   
Dinoflagellates : 16 species (6 genera)
   
Blue-green algae : 7 species (5 genera)
   
Green algae : 3 species (3 genera)
   
Others : 3 species (3 genera)
   
The population density varied from 34000 to 86000 cells / litre.
     
Zooplankton
 
360 species of zooplankton were reported (CMFRI, 1998).
   
Planktonic and Larval forms
   
Copepods 223
   
Cumacea 10
   
Amphipods 52
   
Ostracods 57
   
Isopods 18
   
Decapod larvae 8
     
Commercially Important Shell fishes
 
Penaeid and non-penaeid shrimps, lobsters, crabs, cephalopods, bivalves and gastropods etc.,
     
Commercially Important Fin Fishes
   
   
441 species of fishes have been recorded, among these 200 species are commercial important including sardines, mackerel, anchovies, seerfishes, tunas, ribbon fishes,
     
   
elasmobranchs, perches, catfishes, silver bellies, goatfish, lizard fishes, ribbon fishes, mullets, barracudas etc.,
     
Ornamental Fish
   
   
128 species of ornamental fishes were recorded in Gulf of
Mannar, of which 91 species were recorded around the Mandapam group.
The dominant species were Chaetodontidae, Pomacentridae, Balistidae and Apogonidae.
     
   
Family : Pomacentridae
   
Abudefduf bengalensis -Not evaluated
   
Abudefduf saxatilis -Least concern
   
Abudefduf septemfasciatus - Not evaluated
   
Abudefduf sexfasciatus -Not available
   
Abudefduf vaigiensis - Not evaluated
   
Amphiprion allardi - Not evaluated
   
Amphiprion clarkii - Not evaluated
   
Amphiprion sebae - Not evaluated
   
Chromis dimidiata -Not evaluated
   
Chromis viridis- Not evaluated
   
Dascyllus aruanus - Not evaluated
   
Dascyllus trimaculatus - Not evaluated 
   
Plectroglyphidodon dickii - Not evaluated
   
Pomacentrus trilineatus - Not evaluated
   
Pomacentrus vaiuli - Not evaluated
   
Stegastes fasciolatus - Not evaluated
   
Stegastes nigricans - Not evaluated
     
   
Family : Pomacanthidae
   
Pomacanthus annularis - Least concern 
   
Pomacanthus imperator - Least concern
   
Pomacanthus semicirculatus - Least concern
   
Pomacanthus sexstriatus - Least concern
     
   
Family : Acanthuridae
   
Acanthurus leucosternon - Least concern
   
Acanthurus lineatus - Least concern
   
Acanthurus nigricans - Least concern
   
Acanthurus nigricauda - Least concern
   
Acanthurus triostegus - Least cooncern
   
Acanthurus xanthopterus -Least concern
   
Aethaloperca rogaa - Data deficient 
   
Zebrasoma desjardinii - Least concern
   
Ctenochaetus striatus - Least concern
     
   
Family : Gobiidae
   
Amblyeleotris guttata - Not evaluated
   
Amblyeleotris steinitzi - Not available
   
Amblygobius decussatus - Not evaluated
   
Amblygobius phalaena -Not evaluated
     
   
Family : Apogonidae
   
Apogon compressus - Least concern
   
Apogon fraenatus - Not available
   
Apogon kallopterus - Not evaluated
   
Apogon nigricans - Not evaluated
   
Apogon nigrofasciatus -Not evaluated
   
Apogon novemfasciatus - Not evaluated
   
Cheilodipterus quinquelineatus -Not evaluated
     
   
Family : Tetraodontidae
   
Arothron meleagris - Least concern
   
Arothron nigropunctatus - Least concern
   
Canthigaster bennetti - Least concern
   
Canthigaster solandri - Least concern
   
Canthigaster valentini - Least concern
     
   
Family : Balistidae
   
Balistapus undulatus - Not evaluated
   
Balistoides viridescens - Not evaluated
   
Rhinecanthus aculeatus -Not evaluated
   
Rhinecanthus rectangulus - Not evaluated 
     
   
Family : Caesionidae
   
Caesio cuning - Not evaluated
   
Caesio teres - Not evaluated
   
Caesio xanthonata - Not evaluated
     
   
Family : Caracanthidae
   
Caracanthus maculatus - Not evaluated
   
Caracanthus unipinna - Not evaluated
   
Carangoides malabaricus -Not evaluated
     
   
Family : Carangidae
   
Caranx ignobilis - Not evaluated 
   
Caranx melampygus -  Not evaluated
   
Caranx sexfasciatus - Least concern
   
Gnathanodon speciosus - Not evaluated
     
   
Family : Chaetodontidae
   
Chaetodon auriga - Least concern
   
Chaetodon collare - Least concern
   
Chaetodon melannotus - Least concern
   
Chaetodon meyeri - Least concern
   
Chaetodon octofasciatus - Least concern
   
Chaetodon plebius - Least concern
   
Chaetodon trifascialis - Near threatened
   
Chaetodon trifasciatus - Least concern
   
Chaetodon unimaculatus - Least concern
   
Chaetodon vagabundus - Least concern
   
Heniochus acuminatus - Least concern
   
Heniochus intermedius - Least concern
   
Cheilinus trilobatus - Least concern
   
Cheilinus undulatus - Endangered
   
Chrysiptera unimaculata - Least concern
   
Diodon hystrix - Least concern
   
Diodon liturosus - Not evaluated
   
Ecsenius midas - Least concern
     
   
Family : Serranidae
   
Epinephelus fasciatus - Least concern
   
Epinephelus lanceolatus - Vulnerable
   
Epinephelus tauvina - Data deficient 
   
Cephalopholis boenak - Least concern
     
   
Family : Fistulariidae
   
Fistularia commersonii - Not evaluated
     
   
Family : Muraenidae
   
Gymnothorax favagineus - Not evaluated
   
Gymnothorax fimbriatus - Not evaluated
   
Gymnothorax flavimarginatus - Not evaluated
   
Gymnothorax meleagris - Not evaluated
   
Gymnothorax tessellata - Not evaluated
   
Gymnothorax undulatus - Not evaluated
   
Echidna catenata - Least concern
     
   
Family : Labridae
   
Labroides bicolor - Least concern
   
Labroides dimidiatus - Least concern
   
Thalassoma amblycephalum - Least concern
   
Thalassoma hardwickei - Least concern
   
Thalassoma lunare - Least concern
   
Halichoeres hortulanus - Least concern
   
Halichoeres scapularis - Least concern
   
Hologymnosus doliatus - Least concern
     
   
Family : Lethrinidae
   
Lethrinus harak - Not evaluated
   
Lethrinus nebulosus - Not evaluated
     
   
Family : Lutjanidae
   
Lutjanus biguttatus - Not evaluated
   
Lutjanus decussatus - Not available
   
Lutjanus fulviflamma - Not evaluated
   
Lutjanus fulvus - Not evaluated
   
Lutjanus kasmira -Not evaluated
     
   
Family : Blennidae
   
Meiacanthus atrodorsalis - Least concern
     
   
Family : Holocentridae
   
Myripristis adusta - Not evaluated
   
Myripristis vittata -Not evaluated
   
Neoniphon sammara - Not evaluated
   
Ostracion cubicus - Not evaluated
   
Ostracion meleagris - Not evaluated
     
   
Family : Mullidae
   
Parupeneus barberinoides - Not evaluated
   
Parupeneus barberinus - Not evaluated
   
Parupeneus bifasciatus - Not evaluated 
     
   
Family : Pemoheridae
   
Pempheris vanicolensis - Not evaluated
   
Plagiotremus rhinorhynchos -Least concern
     
   
Family : Ephippidae
   
Platax orbicularis - Not evaluated
   
Platax pinnatus - Not evaluated
   
Platax teira - Not evaluated
     
   
Family : Scorpaenidae
   
Pterois antennata - Not evaluated
   
Pterois volitons -Threatened
     
   
Family : Holocentridae
   
Sargocentron cornutum - Not evaluated
   
Sargocentron diadema -Not evaluated
   
Sargocentron rubrum - Not evaluated
   
Sargocentron seychellense - Not evaluated
   
Sargocentron violaceum - Not evaluated
     
   
Family : Scaridae
   
Scarus frenatus - Least concern
   
Scarus ghobban - Least concern
   
Scarus sordidus - Least concern
     
Flora
 
147 sp. of seaweeds, 13 sp. of seagrass etc.,
     
Endangered species
 
Turtules, Seahorse, Sharks, Dolphins, Whales, Dugongs, etc.,
     
Archeologically/Ecologically Important Places
:
 
 
:
 
No. of. Islands
 
21
 
:
 
Environmental status
:
 
 
:
 
Associated ecosystem
:
 
   
Seaweed, seagrass, pearl banks, sockred chank bed, mangroves, estuaries, mudflats and beaches etc.,
     
   
Seagrass
   
Cymodocea serrulata - Least concern
   
Cymodocea rotundata - Least concern
   
Syringodium isoetifolium - Least concern
   
Halodule uninervis - Least concern
   
Halodule ovalis - Least concern
   
Halophila ovata - Least concern
   
Thalassia hemprichii - Least concern
   
Enhalus acoroides - Least concern
   
Halophila stipulacea - Least concern
   
Halophila decipiens - Least concern
   
Halophila beccarii - Vulnerable
   
Halodule pinifolia - Least concern
     
   
Mangrove
   
Avicennia marina - Least concern
   
Rhizophora mucronata - Least concern
   
Ceriops tagal - Least concern
   
Bruguiera cylindrica - Least concern
   
Lumnitzera racemosa - Least concern
   
Pemphis acidula - Least concern
   
Excoecaria agallocha -Least concern
   
Aegiceras corniculatum - Least concern
   
Rhizophora apiculata - Least concern
     
   
Associated Species
   
Salvadora persica - Not assessed
   
Pandanus sp. - Vulnerable
   
Sesuvium sp. - Least concern
   
Scaevola plumieri -Threatened
   
Suaeda sp. - Least concern
   
Salicornia brachiata - Lower risk near threatened
   
Thespesia populnea - Threatened
     
Gross average productivity in benthic floor
 
74.460gc/m3
     
Major threats
 
Nature Calamities, Industrial pollution(Ash), liquid effluent, mining, fishing,
   
diseases etc.,
     
   
Microbes isolated from the diseased corals
     
   
Bacteria
   
Viblio sp. - Not available
   
Beggiatoa sp. - Not available
   
Desuefovibrio sp. -Not available
   
Achrobacter sp. - Not available
   
Rseudomonas sp. Not available
   
Bacillus sp. - Not available
   
Coryne bacterium sp. - Not available
   
Flavobacterium sp. -Not available 
     
   
Cyanobacteria
   
Phormidium corallytiaum - Not available
   
P. tenue - Not available
   
Lyngbya sp. - Not available
   
Spirulina subsala - Not available
   
Plectonema terebraus -Not available
   
Oscillatoria sp. - Not available
   
Microcystis sp. - Not evaluated 
   
Dark brown coloured sporulating fungus (Source : R.Balasubramanian- 2003)
     
Corals recorded
 
117 species recorded
     
   
Family : ACROPORIDAE
   
Acropora corymbosa - Least concern
   
Acropora cytheria - Least concern
   
Acropora diversa -  Near threatened
   
Acropora formosa - Near threatened
   
Acropora humilis - Near threatened
   
Acropora hyacinthus - Near threatened
   
Acropora indica - Not evaluated
   
Acropora micropththalma - Least concern
   
Acropora millepora - Near threatened
   
Acropora nobilis - Least concern
   
Acropora variabilis - Data deficient
   
Acropora valenciennesi - Least concern
   
Astreopora myriophthalma - Least concern
   
Montipora digitata - Least concern
   
Montipora divaricata - Least concern
   
Montipora exerta - Not avaliable
   
Montipora foliosa - Near threatened
   
Montipora granulosa - Not evaluated
   
Montipora hispida - Least concern
   
Montipora jonesi - Least concern
   
Montipora manauliensis - Least concern
   
Montipora monasteriata - Least concern
   
Montipora spumosa - Least concern
   
Montipora subtilis - Least concern
   
Montipora tuberculosa - Least concern
   
Montipora turgescens - Least concern
   
Montipora venosa - Near threatened 
   
Montipora verrucosa - Least concern
   
Montipora verrilli - Data deficient
     
   
Family : AGARICIIDAE
   
Pachyseris rugosa - Vulnerable
   
Pavona decussata - Vulnerable
   
Pavona divaricata - Not evaluated
   
Pavona duerdeni - Least concern
   
Pavona varians - Least concern
     
   
Family : CARYOPHYLLIIDAE
   
Heterocyathus aequicostatus - Least concern
   
Paracyathus profundus - Not evaluated
   
Polycyathus verrilli - Not evaluated
     
   
Family : DENDROPHYLLIIDAE
   
Balanophyllia affinis - Critically endangered
   
Endopsamnia philippinensis -Critically endangered
   
Dendrophyllia coarctata - Not evaluated
   
Dendrophyllia indica - Not evaluated
   
Heteropsammia michelini - Least concern
   
Tubastrea aurea - Not evaluated
   
Turbinaria crater - Not evaluated
   
Turbinaria peltata -Vulnerable
   
Turbinaria undata - Not evaluated
     
   
Family : FAVIIDAE
   
Cyphastrea microphthalma - Least concern
   
Cyphastrea serailia - Least concern
   
Echinopora lamellosa - Least concern
   
Favia favus - Least concern
   
Favia pallida - Least concern
   
Favia speciosa - Least concern
   
Favia stelligera - Near threatened
   
Favia valenciennesi - Near threatened
   
Favites abdita - Near threatened
   
Favites halicora - Near threatened
   
Favites melicerum  - Near threatened
   
Favites pentagona - Least concern
   
Goniastrea pectinata - Least concern
     
   
Family : FUNGIIDAE
   
Cycloseris cyclolites - Least concern
     
   
Family : MERULINIDAE
   
Merulina ampliata - Least concern
     
   
Family : MUSSIDAE
   
Symphyllia nobilis - Least concern
   
Symphyllia radians - Least concern
     
   
Family : OCULINIDAE
   
Galaxea astreata - Vulnerable
   
Galaxea fascicularis - Near threatened
     
   
Family : POCILLOPORIDAE
   
Pocillopora damicornis - Least concern
   
Pocillopora eydouxi - Near threatened
   
Pocillopora madrasis - Least concern
   
Pocillopora verrucosa - Least concern
     
   
Family : PORITIDAE
   
Goniopora nigra - Vulnerable
   
Goniopora planulata -Vulnerable
   
Goniopora stokesi - Near threatened
   
Porites compressa - Least concern
   
Porites exserta - Least concern
   
Porites lichen - Least concern
   
Porites lutea - Least concern
   
Porites mannarensis - Not available
   
Porites solida - Least concern
     
   
Family : SIDERASTERIDAE
   
Pseudosiderastrea tayami - Near threatened
   
Psammocora contigua - Near threatened
   
Siderastrea savignyana - Least concern
     
   
Family : RHIZANGIIDAE
   
Culicia rubeola - Not evaluated
     
Protection status
 
Biosphere reserve – Declared in 1989
     
   
Gulf of Mannar National Park (Ramanathapuram/ Tuticorin) Tamil Nadu –
   
Declared in 1980 – Area 6.23 sq.km – Ecosystem: 21 islands, coral reefs,
   
mangroves, sea grass beds and beaches.
     
   
Great Nicobar – State of Andaman and Nicobar – Year of Notification 1989 –
   
Area sq.km 10500.

Map

 

Photo source: GOMBRT