3 dead sperm whales wash ashore within 3 days in Tamil Nadu, India

© M. Karunakaran

An adult male sperm whale stranded at Uyali Kuppam near Kalpakkam on Sunday.

The washing ashore of three sperm whales in the last three days has taken fishermen and marine researchers along the east coast by surprise.

While the first dead whale was found near Puducherry on Friday, a second carcass was located at Alambaraikuppam near Marakkanam on Saturday with the third being found at Uyyalikuppam near Kalpakkam on Sunday.

The stranded whale at Uyyalikuppam was a male measuring 50 feet in length and weighing nearly 4 tonnes. The carcass found on Saturday at Alambaraikuppam was that of a female sperm whale which measured 35 feet and weighed nearly 3 tonnes. Both died of injuries suffered on the tail after getting entangled in large nets near the sea surface, said researchers.

Supraja Dharini of TREE Foundation, who visited Uyyalikuppam village, said the flipper of the dead whale was 52 inches long and 30 inches wide, the short dorsal fin was two feet wide -- measurements which indicate that it was full grown adult male. The carcass, which bore superficial injuries, had begun to decompose badly when washed ashore. Oil globules were found all over the dorsal side of the body, she said.

S Venkataraman, director, Zoological Survey of India (ZSI), told TOI that often earthquakes under the sea could disorient these deep sea mammals forcing them to move towards the sea surface where they could have swum into nets and died. With its large population of squids and flow of water currents, the Bay of Bengal region is believed to be a breeding ground for sperm whales though no proper study has been done on this, he said.

But P Dhandapani, formerly with ZSI, suspected the death due to infighting between the older mammals and the young ones. "Certain aspects of the whale's behaviour have not been observed and recorded so far. So it would be difficult to ascertain the exact cause of death," he said.

Sperm whales are one of the biggest and powerful aquatic mammals with a close and complex social structure. They can dive up to 2,000 metres and can hold their breath for two hours. Due to their deep diving capabilities, they frequently hunt giant squids. Spermaceti, an oily substance found in large quantities inside the mammal's head, was used to make candles in the 18th and 19th centuries. Ambergris, another substance, was used to make perfumes. Extraction of both are banned now.