An ecosystem in peril

Print edition : March 28, 2003

The Gulf of Mannar Biosphere Reserve, the biologically richest coastal region in India, is under tremendous pressure, and the legal measures that are in place to protect it have not been quite effective.

PARVATHI MENON in Mandapam and Thoothukudi Photographs: K. Ganesan

ON a blustery day in January, the sea off the Mandapam coast in the Gulf of Mannar is a turgid green that blocks the weak morning sunshine from penetrating its surface. But around the island of Kurusadai, less than a kilometre from the mainland, the picture is altogether different. Here, amidst the shallow coral reefs that fringe the densely foliaged island, plant and aquatic life of an extraordinary range of colour and form pulsates gently in the shallow sunlit water. Colourful molluscs that play dead upon being touched, sea anemones that shudder and collapse into their amoeba-shaped bodies at the first sense of a disturbance, corals of diverse shapes that range from subtle shades of violet to vivid red, and a wide variety of sea weed and sea grass that are also part of the busy environment of the coral reef. The shallow seabed here is carpeted with life in unending motion.

Coral reefs at Mandapam near Kurusadai island in the Gulf of Mannar.-

Often referred to as a "biologist's paradise" Kurusadai island is said to exemplify the biological wealth of the Gulf of Mannar. The island is noted for the presence of a unique endemic organism called "balanoglossus" (Ptychodera flava), a taxonomically unique "living fossil" that links vertebrates and invertebrates.

It is nevertheless obvious, even to the untrained eye that Kurusadai's ecosystem is under tremendous pressure. A good part of its fringing coral reefs, for example, are dead, owing primarily to sedimentation. As in Kurusadai, the coral reefs that fringe a string of 21 uninhabited islands along the coastal arc of the Gulf of Mannar between Thoothukudi and Rameswaram are also threatened to a lesser or greater extent.

The 21 islands, the closest just 500 metres from the shore and the farthest 4 km, with their shallow, marine-rich waters, today form the core area of the Gulf of Mannar Biosphere Reserve. The Gulf of Mannar, with its spectacular yet highly endangered biological wealth, was declared a Marine National Park in 1986 and a Biosphere Reserve in 1989. The reserve covers an area of 10,500 sq km. Its core area is in turn surrounded by a 10-km buffer zone, which further extends inland and offshore for approximately 10 km. It extends from 78o11' to 79o15' E longitude and from 8o49' to 9o15' N latitude.

The Gulf of Mannar falls in the Indo-Pacific region, considered the world's richest in marine biological resources. The Gulf has been chosen as a biosphere reserve primarily because of its biological and ecological uniqueness. The region has a distinctive socio-economic and cultural profile shaped by its geography. It has an ancient maritime history and was famous for the production of pearls, an important item of trade with the Roman empire as early as the first century A.D. Rameswaram, with its links in legend to the Ramayana, has been an important pilgrim centre.

Fishing has historically been the primary livelihood of the coastal communities here and continues to sustain them, although the damage to the coral reefs constitutes a serious threat to this particular livelihood source. The region has been and continues to be famous for its production of chank (Indian conch). The Gulf of Mannar thus constitutes a live scientific laboratory of national and international value. It has 3,600 species of plants and animals that make it the biologically richest coastal region in India. It is, of course, specially known for its corals, of which there are 117 species belonging to 37 genera.

CORAL reefs are a distinctive shoreline habitat of stunning visual appeal found only between latitudes 30oN and 30oS. They grow only where sea surface temperatures are above 20oC, the seabed is kept silt-free by prevailing currents and waves, and there is intense surface sunlight. Most living coral communities do not grow at depths of more than 50 m, although some grow at depths of 100 m.

They are considered the most productive of marine ecosystems, supporting as many as 3,000 species. Their importance stems from the fact that they support a complex biological community - the crevices of their hard structures offer cover to fish and invertebrates and also act as fish nurseries and breeding grounds. Corals are extremely fragile and grow at a very slow pace. Their preservation is therefore essential if coastal fisheries, the primary livelihood source in the Gulf of Mannar, are to be sustained.

The coral reefs are central to the Gulf of Mannar's status as a marine park. But corals are not the only living organisms that constitute this unusual environment. Acting as a linking habitat with the coral reefs to provide shelter and sustenance to aquatic life forms are sea grasses, which grow in communities in the shallow coastal waters. Six of the 12 sea grass genera and 11 of the world's 50 species occur in the Gulf of Mannar, giving it the highest concentration of sea grass species along India's coastline. The sea grass beds are some of the largest remaining feeding grounds for endangered marine mammal protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the dugong (Dugong dugon), which is now rarely sighted in the reserve. All five known species of marine turtles have been recorded as nesting on the islands. Many species of crustaceans, molluscs, gastropods, sponges and fish inhabit the world of coral reef and sea grasses here. The sea grass communities are valuable habitats for commercially valuable aquatic species such as the tiger prawn. Scientific papers on the Mannar bioreserve point out that whales belonging to 10 species have been reported over time in the Gulf of Mannar. They include the toothed whale, the baleen whale, the blue whale, the sie whale, the fin whale and the pilot whale. Two species of dolphins, the spinner dolphin and the bottlenose dolphin, inhabit the Gulf of Mannar and are often caught in fishing nets. So too is dugong or sea cow. Around 200 dugongs were caught in nets in 1983-84, and the figure came down by nine every year between 1986 and 1988, according to an estimate by M. Devaraj of the Central Marine Fisheries Research Institute.

A sea anemone in Kurusadai.-

The Gulf of Mannar is famous for its chanks, although irrational chank fishing has severely depleted the stock. In addition to this, the biosphere reserve has 17 different mangrove species.

THE wide range of legal measures that are in place to protect the biosphere have often resulted in conflicting jurisdictional responsibilities amongst different government departments and agencies. Marine parks that have coral reefs fall under the Ministry of Environment and Forests (MoEF) and therefore come under the ambit of the Wildlife Protection Act (WPA), 1972. The Act, however, has no special provisions to protect coral reefs as they are not included in the schedules to the Act.

Thus, while the illicit removal of corals, which become the property of the government in a national park, would be illegal as per the provisions of the Act, corals are not included in the schedule to the Act, which lists those animals/trophies/items that are prohibited from trade or commerce. This is a glaring anomaly in the Act, which conservationists have long pointed out.

Other national laws bring more government agencies into the picture, like the State Forest Department, the State Fisheries Department and the State Coastal Management Authority. The Coastal Regulation Zone Notification of 1991 outlaws coral mining and places restrictions on industries, operations and processes in an area that extends up to 500 m from the high-tide line. However, it too does not extend protection to pearl culture, or coral digging for limestone (as against coral mining). Having a plethora of enforcement agencies in the picture has often resulted in over-policing, especially towards the poor fisherfolk who depend on the aquatic resources that fall squarely within the `protected' waters of the marine park, for livelihood. On the other hand, the same jurisdictional confusion allows the major offenders - the owners of the large trawling boats that dredge the ocean bed, or those who finance coral mining operations - to get away.

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