Global Warming

Global Warming: Climate Change Pose Threat to Coral Reefs in Gulf of Mannar

Bleached corals will recover only if the temperature level comes down, says expert The coral reef wealth of the Gulf of Mannar, which is being conserved through joint efforts of various governmental, non-governmental and research agencies, is now facing a different kind of threat — global warming and consequent climate change. Coral reefs, known as [...]

Bleached corals will recover only if the temperature level comes down, says expert
The coral reef wealth of the Gulf of Mannar, which is being conserved through joint efforts of various governmental, non-governmental and research agencies, is now facing a different kind of threat — global warming and consequent climate change.

Coral reefs, known as rain forests of the sea, are a source of food security and livelihood options for hundreds of millions people, coastal defence and tourist hotspots. The Gulf of Mannar (GoM) is one of the four important coral reefs in India and thousands of artisanal fisher folk are dependant on fishery resources from this reef area.

Though direct human impacts have resulted in vast destruction of the reef area and associated flora and fauna for the last three or four decades, strengthened enforcement of law, inclusion of corals under Schedule I of Wildlife Protection Act, 1972 and enhanced awareness among the coastal community of coral reef conservation have arrested the decay.

After the tsunami and various conservation and eco-developmental activities, coral mining was completely stopped in 2005 and there has also been a reduction in destructive fishing activities near the reef. These factors have resulted in the enhancement of live coral cover from 37 per cent in 2005 to 43 per cent in 2009 owing to stable substratum, initiation of coral restoration on six islands, successful reproduction and high coral recruitment.

However, the effect of global climate change is always a threat to the corals, as they are very sensitive, and also to the fish population associated with reefs. The impact of climate change was clearly visible in 1998 in the Indian Ocean with many reefs, previously regarded as near pristine, seriously affected. The corals of GoM were also affected in 1998.

The percentage of bleaching in live coral cover depends mainly on the wind, water currents, rainfall, turbidity and depth. The maximum affected corals are in the shallow waters – ranging from depths of 0.50 metres to 2 metres.

This summer, the coral bleaching was observed from the second week of April when the average surface water temperature was between 29.1 degree Celsius and 33 degree Celsius in Mandapam; 29.3 degree Celsius and 33.1 Celsius in Keezhakkari ; and 29.3 degree Celsius to 33.6 degree Celsius in Tuticorin.

Any external disturbance in the form of heavy trawling would destroy the already affected coral reef. It is essential that the coral areas should not be disturbed by the fisher folk by any kind of illegal fishing and other activities such as trap fishing, trawling, seaweed collection, shore seine operation, ornamental fish collection etc. The Marine National Park authorities have also intensified the vigil in order to avoid any human disturbance in the reef areas.