Warm waters bleach coral reefs in south

V M Mariappan, 48, sits idling at home recalling how 10 years ago men from his village would cast nets into the sea and find a rich catch. Shore-netting fishermen, as they are called in the Tuticorin port area, use a method of fishing where an entire village gathers on the beach to draw in semicircular nets laid in the early hours a few nautical miles from the coast. Today, the catch has dwindled in the region, and Mariappan who grew up here, finds himself in unfamiliar territory. “We should have started fishing by middle of June, but there is no fish near the shore even in September,” says the fisherman.

Earlier seasoned fishermen could sense a school of fish by judging currents and winds. But their traditional knowledge fails these men today. “At this time of the year there should not be strong winds. But it has been nearly 20 days and we have not been able to set sail because of treacherous gales,” said G Arul, a fisherman and president of Pamban Country Boat Fishermen Association.

Far away from Arul’s hut, world leaders are busy putting together a document that will be debated at meeting in Paris later this year. Scheduled between November 30 and December 11, the UN Climate Change Conference would aim to achieve a legally binding and universal agreement on climate change once and for all. There have been reports that the polar ice caps and the Greenland ice mass are melting faster and that consequently sea levels would rise at a more rapid pace than expected. But for the likes of Mariappan and Arul, such conferences have no relevance, nor do they understand the melting ice cap theory. Unaware of the trends, these men have been enduring the brunt of climate change for years now, forced to venture deeper into the ocean for their catch; their attempts to adapt may be their only chance for survival.


But unlike the fishing community, marine life -- also dependent on the sea -- is not adapting to change. The new climatic patterns have taken a deadly toll on it. In the Gulf of Mannar (GoM) region in Tamil Nadu, rising temperatures have bleached corals and are threatening to expose the land mass to direct waves. Once known for its chain of 21 islands, the GoM today has 19 land masses with one among them four-fifths submerged. Former director of Zoological Survey of India, Dr K Venkataraman, who has worked extensively on corals, said a mass bleaching had occurred in the Indian Ocean due to the 1997-98 El Nino. “There are around 40-45% of live corals in the GoM. In the last three decades, GoM has lost a lot of its corals,” said Venkataraman, adding that GoM was once home to pearls of high quality which are not found today.

Vanishing coral reefs leave the substratum of islands open to waves. “Corals act as shields and guard the land mass. But once they die and there is no recolonisation, the waves eat away the land mass,” said director of Suganthi Devadason Marine Research Institute Dr J K Edward Patterson.

Marine vegetation too is under threat. Rising water levels and temperature are detrimental to seagrass that sustains animal life. According to seaweb.org, a website that compiles research on ocean issues, “increased water depth will restrict the amount of light reaching seagrasses thereby reducing photosynthesis, productivity, and geographic distribution.”

Further, an increase in temperature is likely to affect the peripheral parts of seagrass and also promote growth of competitive algae that would eventually reduce the light and carbon dioxide the vegetation needs to survive. On the land too, changes are visible. The sea laps the basement of the famous Kappal Matha church in Uvari. Locals say the sea was at least 500m away before the 2004 tsunami. To save this coastal town in Tirunelveli, the district administration is constructing a groyne but residents do not see much hope. “The sea is eroding the shore faster than ever and it is worse after the tsunami. The groyne they are building is not long enough to prevent sea erosion”, says former head of Uvari town panchayat M Raymond.

Corroborating Raymond, Bangalore-based marine biologist Naveen Namboothiri said there is truth in what the fishermen say about the sea.

“The winds are connected with the sea currents and there has been significant change in them after the tsunami as the seabed was altered due to the impact. Climate change has slowed down sea currents leading to a cascading effect on coastal ecology,” said Namboothiri.

But all is not lost either. Venkataraman says the situation can be salvaged and the marine diversity in Gulf of Mannar, especially the corals, can be protected. “We have all the basic data, now we need a permanent monitoring plan. Focus should be on sustainable management of coral health and an integrated plan to oversee our marine resources. All this is time-consuming, but we will benefit in the long run,” he said.