The Gulf of Mannar Biosphere Reserve

Page - November 8, 2004
The Bay of Bengal is a world treasure, supporting a variety of special and fragile habitats including pristine islands, mangrove forests and coral reefs and is home to such endangered creatures as sea turtles, dugongs, whale sharks and seahorses. Millions of people are dependent on these waters. Unfortunately, destructive coastal development, unsustainable fishing practices, climate change and illegal trade in protected species are all taking their toll. The Gulf of Mannar Biosphere Reserve is the first marine biosphere reserve in Asia, located in the Southern part of the Bay of Bengal. The reserve was created by the Indian Government in 1989 when the IUCN Commission on National Parks and Protected Areas, with the assistance of UNEP, UNESCO and WWF, identified the Reserve as being an area of "particular concern" given its biological diversity. But despite its protected status this extraordinary Reserve is under threat.

Dugongs, Sea Horses and mangroves, all play their part in Gulf of Mannar being a Marine Biosphere Reserve.

The Gulf of Mannar Biosphere Reserve - a world treasure

The Gulf of Mannar is the biologically richest coastal region in India with 3,600 species of plants and animals known to live within its boundaries. In the Gulf of Mannar you can still see the globally endangered dugong, several species of dolphins and whales and three species of endangered sea turtles. Furthermore, the Reserve is home to sea horses, 450 species of fish, hundreds of species of sea cucumbers, sponges, all kinds of corals and species of sea grass found nowhere else. In addition more than 150 species of bird are found on islands in the reserve. Vital to the ecology of the reserve are the 17 species of mangrove which act as important fish nurseries.

The reserve covers 10,500 sq. km and has 21 islands with continuous stretches of coral reef. The core area of the reserve is comprised of a 560 km2 core area of coral islands and shallow marine habitat.

Commercial fishing is done in about 5,500 sq. km. and nearly 50,000 people dwelling in 47 villages along the coastline bordering the Gulf of Mannar depend directly on the natural resources of the Biosphere reserve for their livelihood.

The Reserve's fishery is dominated by fish species like lesser sardine, silver belly, mackerel, anchovy, thread fin, bream, lobster, molluscs and prawns.

Threats to the Gulf of Mannar Biosphere Reserve

The fragile Coral reefs and the unique flora including Sea Grasses of Gulf of Mannar, which provide homes to an abundance of marine creatures, are under multiple threats.

Destructive coastal development

The most direct threat to the Marine Reserve is the proposed Sethu Samudram Canal on the coast of Tamil Nadu. The canal threatens to destroy the near pristine Gulf of Mannar Biosphere Reserve.

The construction of the canal will destroy the unique and fragile marine ecology of the area through constant dredging to maintain a canal depth of about 10 m. Aside from the immediate destruction of the sea bed, the consistent churning of sediment will smother the coral reefs adjacent to the canal. The increase in shipping traffic will inevitably result in an increase in oil spills and marine pollution.


Untreated Chemical effluents, including vast quantities of mercury and dumping of fly ash from the industries and thermal power plant in Tuticorin are the biggest threat to the health of the marine reserve

The dumping of fly ash slurry into the Karapad bay by the thermal power station has resulted not only in filling up of an extensive portion of the Bay, but also fly ash entering the sea directly. The ash, on being carried far into the sea has caused irreversible and extensive damage to the sedimentary organisms, algal beds, chank (Indian conch), pearl oysters and to all the corals and associated creatures. Mangroves, which grow on the margin of the shoreline, have accumulated alarmingly high levels of ash borne minerals.

Mechanized fishing

The increase in the number of mechanized fishing vessels using bottom trawls results in physical damage to the fragile corals - the heavy trawl gear breaking off branches and destroying fragile structures that have taken many years to grow. In addition, large numbers of juvenile fish and other marine species are taken in the fine mesh nets as bycatch. Sea grass beds which act as important spawning and nursery grounds for many fish species are also harmed by inappropriate bottom trawling practices.

Also the increased numbers of larger mechanized boats that catch most of the fish threatens the livelihoods of artisan fishermen. Mechanized boats use multi-gear systems such as fish trawls, pair trawls (illegal), drift nets, gill nets and bottom set gill nets. Smaller, traditional motorized and non-motorized boats use bag nets, purse seines, gill nets, trammel nets, and hook and line set-ups. The on-going mechanization of the fishery has displaced traditional fishermen and women, forcing them to take up the harvesting of wild seaweed or coral, which has now reached a point of exploitation.

Coral mining

More and more coral mining takes place in the southern part of the Gulf of Mannar Biosphere Reserve. It has stripped most of one island's coral and threatens to do the same in other parts of the park.

As the local fishermen cannot catch enough fish anymore, they are forced them to take up other destructive practices such as mangrove cutting and coral mining in and around the park, that are locally used as nutritional supplements, souvenirs and cosmetics.