South East India

Summary

The districts of Tuticorin and Ramanathapuram in the state of Tamilnadu have been identified as climate change hotspots of the Indian subcontinent. The coastal district of Ramanathapuram which is bordered by Gulf of Mannar on one side and Palk bay on the other side scores the highest in the vulnerability index among the districts of Tamil Nadu. Precisely the gulf extends from Rameshwaram in the north, to Kanyakumari in the south, fringing nearly 30% of Tamil Nadu’s total coastline (Haastrecht & Schaap 2003). Gulf of Mannar envelops an area of 10,500 sq.km along 8o 35’N- 9o 25’ N latitude and 78o 08’E- 79o 30’E longitude. On the Indian side, the gulf is situated on the south east border of Tamil Nadu, India’s southernmost maritime state (Rengasamy et al., 2003). It has been reported that the total area of the Indian EEZ is approximately 2.02 million square kilometers and that of the Gulf of Mannar is 15,000 km2.

Oceanographical context

Over the Bay of Bengal the upwelling occurs in the western coastal boundary upwelling (whereas the classic coastal boundary upwelling regions are along the eastern boundary of the oceans). The East India Coastal Current (EICC) in the Bay of Bengal reverses direction twice a year. By late October, water from the Equatorial Jet enters the Bay in the east and cyclonic circulation is established. The role of freshwater and that of coastal Kelvin waves propagating northward along the eastern boundary of the Bay of Bengal plays important role in the local forcing and governs the dynamics of Upper Ocean.

Economic and social context

Among the 49 coastal villages, 38 are in Ramanathapuram district and 11 are in Tuticorin district bordering the Marine Biosphere area. 14,000 out of the 54,000 traditional fisherfolk of these villages are active fishermen earning an average of Rs.500-5,000 per month.

The traditional fishing is the primary occupation of the coastal village inhabitants in the GoM. They are below poverty line, with poor education and infrastructure facilities and are in a permanent disadvantageous position both socially and economically. Majority of fishermen are in debt due to inadequate income from fishing. Ramanathapuram district contributed 23% to the overall marine fish state production while Turticorin contributed to 13%. The proportion of crafts used by the traditional fishermen is 87%, while only 13% of the 1573 crafts operating in the GoM are mechanised trawlers showing the socioeconomic importance of traditional fishing activity. Small-scale fishing is carried out predominantly in the ‘trapped sea’ between the islands and the mainland. Fishing takes place throughout the year, but changes in nature according to the availability of different species. Use of non-motorised or motorised crafts with low horse power out board engines and passive gears is prevalent.

Important fisheries

The GoM supports finfish and shellfish fisheries as well a number of aquaculture activities. The finfish fishery includes perches, carangids, barracudas, mackerels, milkfish, mullets, tunas, sardines, scrombroides, silver bellies, pomfrets, lethrinids, groupers, sharks and rays. The shellfish fishery includes oysters, mussels, clams, prawns, lobsters and crabs. In addition to seaweed, aquaculture trials have been conducted for pearl oysters, edible oysters, crabs, sea cucumbers, prawns, and milkfish. Elasmobranchs are the largest group of fishes and are well represented in the fishery wealth of Rameshwaram Island on the Palk Bay side. The common fishes found in this area include Scoliodon, Rays, Skates, Tiger-sharks, Saw-fish and Hammer-head sharks. The squid is the most common edible mollusc of Rameswaram.

Biodiversity of the region

The GoM and the Palk bay are endowed with a rich biodiversity of coral reefs, rocky shores, sandy beaches, mud flats, estuaries, mangrove forests, sea-weed stretches and seagrass beds. These ecosystems support a wide variety of fauna and flora including rare cowries, cones, volutes, murices, whelks, strombids, chanks, tonnids, prawns, lobsters, pearl oysters, seahorses and sea cucumbers. Among other reasons, the GoMBR is particularly important, it provides a safe habitat to the declining populations of the endangered dugong, an herbivorous aquatic mammal of the Indian Ocean. Krusadai Island in the Mandapam group is of biological significance. The island harbours a unique, endemic organism called "balanoglosus" (Ptychdera fluva), a taxonomically unique "living fossil" which links vertebrates and invertebrates. The island is referred to as "biologist's paradise". This island harbours three species of sea grasses endemic to Gulf of Mannar. 

Key Climate Concerns

  • Occurrence of Sardine events and Unusual landings of mackerel over the last two decades
  • Loss of coral ecosystem due to changes in salinity due to heavy rains and intense storms  
  • The Bleaching of corals in the GoM during caused by EI-Nino phenomenon increasing global seawater temperature (April-May 1998.) 
  • The tsunami of 26th December 2004 caused social and ecological damage to many of the islands in the GoM. 
  • Temperatures have risen by an average of 0.90±0.1ºC per century in the GoM.