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Death in deep blue seas: Sharp spike in dolphin, whale deaths

A fifty-feet sperm whale was found stranded on the Pacific beach in California in April 2015. Photo Courtesy: Nicole Strasser, Pacifica, California Photograph: (WION)

New Delhi Sep 22, 2016, 11.41 AM (IST) Sana Khan

Abhishek Jalalabad spent the 23rd of March, 2016 praying that he did not see a whale at the Palolem beach in south Goa. Just a day earlier, a local branch of conservation group 'World Wild Fund' got in touch with him. It was a distress call. They wanted his help in rescuing an eight-foot dwarf sperm whale.

Jalalabad, a marine scientist, rushed to Palolem beach. By then, tourists and lifeguards had managed to release the whale into the Arabian Sea. But he stayed back on a hunch and the rescuer's worst fears came true at about midnight.

The eight-foot whale returned to the shore in the dark of the night. Roughly 20 minutes after Jalalabad and his colleague, assisted by tourists, sent it back into the water, the whale beached again. This time, it lay still, dead.

This was one of the roughly 90 reported cases of whale and dolphin strandings along the Indian shores in the past 20 months.

More than 13,000 kilometres away from Goa is California’s Pacifica Beach. Nicole Strasser was heading home after her night shift at the hospital when she experienced a nasty stench in the parking lot. Something was afloat on the beach. To her dismay it was a dead whale -- the second she saw in a matter of weeks.

When WION spoke to Strasser, she was anxious. Last year she had spotted hundreds of whales in the sea. This year she has only seen dead ones.

More and more mass whale and dolphin strandings are being reported the world over. Once beached, they face the risk of injury and death from dehydration. However, January was especially baffling for marine scientists in India. More than a hundred short-finned pilot whales – a species of dolphins – were found stranded along a 15-kilometre stretch of a beach in Tamil Nadu on the east coast of India, of which 45 died.



N Vasudevan, a conservationist for the Indian state of Maharashtra that flanks the western coast, told WION, "The numbers are unusually high. Earlier, we rarely saw so many whales being washed ashore. We cannot say what is causing this.”

 


No marine scientist can pinpoint the exact cause behind cetacean stranding. Giuseppe Notabartolo di Sciara is the president of Tethys Research Institute in Milan that is a non-profit organisation supporting marine conservation through science and public awareness.

"The news about whales and dolphins washing up dead in India in increasing numbers is worrisome. It is clear that there isn't a single agent at work, but multiple causes, and each event has its own story,” di Sciara said.

"We humans are forgetting that all our activities conducted in unsustainable ways at sea are destroying not only the animal world, but our world as well," di Sciara added.

Human disruptions also cost lives with dolphins getting caught-up in fishing lines and dying. A baby dolphin died after it was scooped out of shallow water by a swimmer and passed around at a beach in Argentina by a mob intent on clicking selfies with it.

In 2015, scientists made a grim discovery in Patagonia, southern Chile: 337 dead Sei whales. This is the world's biggest mass whale stranding event ever recorded.

A year on, investigators still have no explanation. Professor di Sciara speculated that the large number of dead whales in Chile must have a single cause, whereas it was “very likely" that the increase of dead whales in India is due to human activities, like plastic waste disposal in the sea, overfishing and underwater sonar”.

 

In 2004, the Scientific Committee of the International Whaling Commission concluded that “there is now compelling evidence about military sonar having a direct impact on the beaked whales”.

In 2001, the US Navy acknowledged that its active sonar played a role in the stranding deaths of 14 beaked whales, two minke whales, and a dolphin in the Bahamas in 2000. Autopsies of the beaked whales revealed that the animals had suffered acoustic trauma resulting in hemorrhaging around the brain, in the inner ears, and in the acoustic fats located in the head that are involved in sound transmission.

Dr N Ramaiah, chief scientist at the National Institute of Oceanography, however, felt behavioral patterns could be a possible factor in the mass stranding of 45 pilot whales in India this year. "As these pilot whales move in large groups, each pod has a leader. Sometimes they land up on the shore while following their leader that may have lost its way due to disorientation,” he said.

Mass strandings may not even be a true indicator of what's going on in the ocean. Clare Embling, lecturer of Marine Ecology at Plymouth University in the United Kingdom, said stranding "is always difficult to place in context because only a small number that die will strand". Many big mammals sink, and where they die in relation to ocean currents, can influence how many strand. Seeing 30 sperm whales strand is upsetting, but it is difficult to know whether it is a fluke climatic event that caused it, or something more alarming."

One major factor, however, is plastic. It is found floating in all the world’s oceans. Among 10 species of baleen whales, 60 per cent have been found to be tangled in ocean debris, while 20 per cent have ingested plastic or other waste by mistake. The study of 65 different species of toothed whales by environmental group Greenpeace reveals that 8 per cent managed to entangle themselves in ocean waste, another 32 per cent ended up ingesting plastic dumped in the ocean.

Kumaran Sathasivam, coordinator of the Marine Mammal Conservation Network of India, said: "Whales and dolphins consume plastic in the ocean thinking it is food. The ocean is already so polluted and it will take a lot of time for all this plastic to deteriorate." But to reduce all cetacean strandings to one cause is difficult without proper statistics, experts say.  

Independent marine ecologist, Dipani Sutaria, says, "A concerted effort to document and publicise these [stranding] events has begun only since 2013. We now have researchers or interested individuals all along the west coast." Sutaria points out that 11 Baleen whales were found stranded in 2015 on the west coast of India -- eight in Maharashtra and three in Gujarat.   
Sutaria believes the number of cases reported is directly proportionate to the response network on the coasts. There are fisher-folk, tourists, forest department staff, independent researchers, and local organisations that pass on information in case a marine mammal washes ashore.  

While this mysterious uptick of beached whales is recent, the phenomenon itself is surprisingly old. Evidence of mass beaching has puzzled scientists as far back as 300 BC. “It is not known why they sometimes run aground on the seashore,” said Greek philosopher Aristotle. “It is asserted that this happens when the fancy takes them and without any apparent reason."  

(WION)  


 

 
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