They are one of the oldest ecosystems in the world, shielding humans from tsunamis and hurricanes and sheltering a variety of colourful fish.
Today, this fragile structure, which occupies less than one per cent of the earth’s surface, is facing multiple threats: release of effluents from industries and waste from power plants; cultivation of an invasive alien seaweed; manual collection of reefs; and bleaching due to increased heat conditions. These activities are systematically destroying coral colonies in the Gulf of Mannar (GoM) region.
K. Venkataraman, Director, Zoological Survey of India, says 108 coral species are found in the Gulf of Mannar Biosphere Reserve, with many more yet to be identified.
The reef colonies in the Palk Bay are completely dead now, what with increased bleaching especially from May to July; they were alive nearly four years ago. A few years ago, the coral colonies recovered, but the process has stalled because of high siltation from human interference. The best pearls were found only in the Gulf of Mannar region a few decades ago, and the best divers in the world. But there are no pearls or oysters, and no divers today.
Shell collection, and an increased demand for coral reefs and other marine organisms for ornamental purposes, and for sea cucumbers, sea horses and pipe fishes for their medicinal value have pushed these species to the brink. After a lot of struggle, the sea cucumbers have been brought in the endangered category, Dr. Venkataraman points out.
Another major problem is the growth of an invasive alien weed species: Kappaphycus alvarezii . A large portion in the northern part of the GoM has been fully colonised by this weed, which is mainly bought by multinational companies. The species has almost covered 15 square km in the northern region, never allowing the sunlight to reach the seabed and choking the corals to death, he explains.
Many items collected from the region are being exported, including ornamental fishes and shells. Even the curios, souvenirs and trophies that are exported were all collected from here. Climate change has forced several farmers to turn to the sea as an alternative source of livelihood.
Officials in charge of the bio-reserves concede that it is difficult to manage the 150-km coastline, stretching from Rameswaram to Tuticorin, with a meagre staff of 50. The Union government is chipping in with Rs. 10 lakh every year for patrolling, hiring boat drivers and appointing anti-poaching staff. Even that sum is not released regularly, so protection work becomes very tough. This year, the fund has not come so far, they say.
Shekhar Kumar Niraj, Conservator of Forests, Virudhunagar, says that in an attempt to regenerate the corals, the department provided artificial substratum near 10 islands in the biosphere. In the past four years, with the help of this technology, corals have regenerated successfully on three square kilometres in six of the 21 islands. In an encouraging sign, fish have come in large numbers and colonised the regenerated corals.
Shell collection and an increased demand for coral reefs and other organisms have pushed species to