The Hindu , 23 March 2006

Study begins to map depth contours of sea

CUDDALORE: The Centre of Advanced Study in Marine Biology of Annamalai University, located at Portonovo, has undertaken the bathymetry study to ascertain the depth contours of the seas after the tsunami from Cuddalore to Nagapattinam.

The Integrated Coastal and Marine Area Management Department, under the Union Ministry of Ocean Development, has assigned the task to the centre, according to L.B. Venkatrangan, Vice-Chancellor and T. Balasubramanian, Director of the centre.

They told The Hindu that in the post-tsunami many improbabilities were turning into realities, as many surprises were cropping up from the fathoms of the seas. After the disaster, there seemed to be a vast variance in the marine system with increasingly bigger animals surfacing off the Cuddalore coast.

The region was not the natural habitat of the sea creatures such as sperm whales. Recently a highly decomposed body of a sperm whale was washed ashore near Cuddalore, which astonished the scientists.

Given their size and area of operation, these sea animals required considerable depth to move about. Moreover, they required ample supply of smaller marine animals for their food. Therefore, it could be surmised that significant transformation should have taken place in the sea to attract these mammoth sea creatures nearer the coast.

For several decades before the tsunami, no such sightings of whales were reported because earlier the shallow coastline rarely attracted them.

Mr. Balasubramanian said these animals required at least a depth of 1000 metres to sail. But, as per the available statistics, such depth could be obtained only beyond 32 km off the coast.

Only at Seyyar near Marakkanam has the required 1000-metre depth at 12 km from the shore. However, the continued presence of increasing number of dolphins, whales, enlarged sailfish and black marlins closer to the coast, were the indicators that conducive environment prevailed for their habitation.

The director said the bathymetry study was being conducted with instruments such as echo sounder, wave recorder, tide gauge and so on.

He hoped that the study would reveal valuable insight into the bowels of the sea that would in turn enrich the fund of knowledge of the marine scientists and also put on alert the decision-makers.