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Gulf of Mannar Marine Biosphere Reserve

Gulf of Mannar Marine Biosphere Reserve (GoMBR), extends between Toothukudi and Ramanathapuram districts. It is located in the southeastern coastline of India, and is a unique marine environment rich in biodiversity. The GoMBR came into existence on 18th February 1989, by a joint declaration of the Government of India and the Government of Tamil Nadu. The same has been recognized by the Man and Biosphere (MAB) Programme of UNESCO. GoMBR is one of the most biologically diverse regions in India, comprising 117 species of corals, 450 species of fishes, 4 species of sea turtles, 38 species of crabs, 2 species of lobsters, 12 species of sea grasses, 147 species of marine algae, 160 species of birds, 641 species of crustaceans, 108 species of sponges, 731 species of molluscs, 99 species of echinoderms, 4 species of sea horses, 12 species of sea snakes, besides 11 species of mangroves. The Reserve is also home to several globally important and highly threatened species like the Dugong, whale shark, sea horses, Balanoglossus, green sea turtle, Hawksbill turtle, dolphins, sacred chanks etc. The region has a recorded history of over 2000 years of settled agriculture, well established human-made tanks and supportive water bodies. Seagrasses provide immense indirect ecosystem services to commercially important fishes and macroinvertebrates by acting as nesting and nursery grounds. Abundance of fish larvae in the seagrass bed, reported at 198 individuals/100 m2, was higher than the open sandy areas, with 112 individuals/100m2 in GoMNP in 2008. The region has a high potential for eco-tourism, as the MNP is situated between Rameswaram and Tuticorin, with rich coral reefs and seagrass. It also acts as an educational site, where researchers, bird watchers have studied the area for years. The soil is typical coastal sand, strewn with shingles, and there are swamps in areas of Van Island, Kasuwari Island, Poomarichan Island, Pullivasal Island, Krusadai and Shingle islands. Quick sand is seen in parts of Mulli and Krusadai Island. Mangrove soils are slightly acidic. Anaerobic condition in the soils helps sulphate-reducing bacteria to produce hydrogen sulphide. The characteristic black or grey colour of the soil is due to reduction of ferric compounds to ferrous sulphides. Landscape composed of beaches, algal beds, minor deltas, backwater areas, creeks, mudflats, sea grass beds, coral reef, salt marshes& mangroves. Beaches-extensively spread along GoM coast. It is gently sloping marked with altered crusts& troughs formed by wave action; coastal areas between Mandapam &E of Vaippar River-covered by 12 beach ridges; sand spits are in the S. side of Tuticorin& SW Rameswaram shore. Swales& backwater zones are between coastal plains of Mandapam& Kottakkarai River. Mudflats are near Vaippar River mouth, around Valinokkam backwater lagoon, Kallar River mouth& Gundar River mouth; 21 offshore islands-made up of calcareous dead reef &sand. Coral reefs extend from S of Rameswaram-Tuticorin, believed to be once covered with dense mangrove forests. Salinity values of GoM range between 31.7 to 35.2 ppt (part per thousand). Peak salinity values coincide with peak temperatures in the Gulf. Coastal areas-the rate of evaporation exceeds rate of freshwater input, hence salinity has been reported to exceed 40 ppt. Salinity of mangroves fluctuates considerably ranging from 3 to 33 ppt. Dissolved Oxygen (DO) in the waters GoM is dependent on temperature, salinity, oxygen solubility, consumption and production. Sandy Beaches contributes sand, minerals and better catchment area. Coral reefs are tapped for building material, live trade and as source material for medicine. The site is noteworthy as it is located in one of the major bird migratory routes, called ?Flyways?. It lies in CAF (Central Asian Flyway), of the international flyway zones Coral mining or dredging, anchoring of boats, Coral Bleaching, Predator-Crown of Thorn starfish Siliceous Sponges-fragment the corals, Over exploitation-especially-Holothurians+Ornamental fishes.

Salient Features

First marine biosphere reserve in south & south-east asia, Supports more than 1,10,000 families from 268 fishing villages, International bird and biodiversity area with iba site code: in-tn-09 and is part of central asian bird migratory flyway

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Location Ramanathapuram
Area 52671.88 hectares
Wetland Type Marine or coastal wetlands, A: Permanent shallow marine waters
Date of Designation 08-04-2022
Ramsar Site No. 2472

Values and Benefits

  • Provisioning Services
  • Food for humans
  • Biochemical products
  • Regulating Services
  • Maintenance of hydrological regimes
  • Erosion protection
  • Climate regulation
  • Hazard reduction
  • Pollution control and detoxification
  • Cultural Services
  • Recreation and tourism
  • Scientific and educational
  • Supporting Services
  • Biodiversity
  • Soil formation
  • Nutrient cycling

Threats

  • Biological resource use
  • Logging and wood harvesting
  • Fishing and harvesting aquatic resources
  • Natural system modifications
  • Vegetation clearance/ land conversion
  • Unspecified/others
  • Human intrusions & disturbance
  • Recreational and tourism activities
  • Unspecified/others
  • Pollution
  • Household sewage
  • urban waste water
  • Industrial and military effluents
  • Agricultural and forestry effluents
  • Transportation and service corridors
  • Shipping lanes
  • Human settlements (non agricultural)
  • Commercial and industrial areas
  • Unspecified development
  • Water regulation
  • Drainage
  • Water abstraction
  • Water releases
  • Agriculture & aquaculture
  • Marine and freshwater aquaculture
  • Energy production and mining
  • Mining and quarrying
  • Geological events
  • Earthquakes/tsunamis
  • Climate change & severe weather
  • Droughts
  • Temperature extremes
  • Storms and flooding
  • Invasive and other problematic species and genes
  • Invasive non-native/ alien species

Ramsar Criteria

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Management Authority Gulf of Mannar Biosphere Reserve (GoMBR), extends between Toothukudi & Ramanathapuram districts; joint declaration of Government of India & Government of Tamil Nadu.
Protection Status UNESCO Biosphere Reserve

Species of Global Conservation Significance

Notable Species: There are 117 coral species identified in GoMBR, belonging to 40 genera & 14 families; all protected under Schedule-I of the Indian Wildlife Protection Act (1972). GoMBR has 181 species of seaweedscomprising green, brown, red & blue-green algae out of 1158 species found in the country. 17 economically important species from agarophytes, carrageonophytes, alginophytes and edible seaweeds are recorded here. Seagrasses are marine angiosperms. Halodule uninervis is the dominant primary species in the intertidal zone occurring on sandy and muddy substratum. H.uninversis act as stabilizer and sediment accumulator; occur as a bed of monospecific community or mixed with Cymodocea rotundata, C.serrulata, Halophila ovalis & Enhalus acoroides. C.serrulata occurs extensively in most islands forming significant browsing ground for endangered Dugongs. Thalassia hemprichii and H.uninervis beds are important habitats for Holothurids. A total of 11 mangrove species, 17 mangrove associates & 201 flowering plants are identified; Avicennia marina, Bruguiera cylindrica, B.gymnorrhiza, Ceriops tagal, Excoecaria agallocha, Lumnitzera racemosa, Pemphis acidula, Rhizophora apiculata & R.mucronata ? belonging to 5 families predominating Rhizophoraceae. GoMBR is the only region in India reported to have all 5 sea turtle species. 4 of the 7 sea turtle species found worldwide are reported here-Olive Ridley (Lepidochelys olivacea), Green Turtle (Chelonia mydas), Hawksbill Turtle (Eretmochelys imbricata) & Leatherback Turtle (Dermochelys coriacea). All 4 species are protected under Schedule-I of the Indian Wildlife Protection Act (1972), and also listed in Appendix-I of Convention of International Trade in Endangered Species of Wild Fauna and Flora (CITES). Dugong distribution is discontinuous & patchy in the tropical Indo-Pacific region. In India, dugongs are presently recorded in Gulfs of Mannar & Kutch and Andaman & Nicobar Islands. They are protected under Schedule-I of the Indian Wildlife Protection Act (1972), usually found in calm, sheltered, nutrient-rich water, <5 m deep, usually in bays, shallow island & reef areas with extensive seagrass beds. However, they are sighted near reefs up to 80 km offshore at 37 m depth. It is considered to be rare over most of its range (Bertram& Bertram, 1968). Fishermen along coastal Tamil Nadu are familiar with Whale Shark (Rhincodon typus), locally known as \'Panai meen\'. As per Bird Life International, 187 species of aquatic (shore & pelagic) and terrestrial birds are identified from GoMBR. Red Knot is a regular winter visitor in small numbers; Crab Plovers, Bar-tailed Godwit occur in Manali and Muyal islands; Greater flamingos frequent GoMBR, making it the 3rd largest IBA & an important wintering ground along E. coastline. Rare waders include Broad-billed Sandpiper, Eastern Knot, Dunlin, Long-toed Stint and Red-necked Phalarope.

Endangered: 21
Vulnerable: 27
Critical Endangered: 8

Species Count

Birds 187
Fishes 454
Plants 569
Mammals 1
Reptiles & Ambhibians 16
Coral Reefs & Sea Algae 225

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