On the eve of November 2 (Monday) a pod of at least 120 short fin pilot whales became stranded on the beaches of Sri Lanka’s western coast. It was a sight never seen before in the island nation. This, in fact, was the biggest ever mass beaching incident reported in Sri Lanka or in any other South Asian country to date.
According to witness accounts, a few whales were found beached in the afternoon on Monday, only for the numbers to increase rapdily towards late evening.
Overnight rescue
But even as public movement in the country’s Western province was restricted due to the quarantine curfew, on the day rescuers and volunteers rushed to the Panadura beach to assist in saving the mammals and to direct them back into the deep waters. As the Sri Lanka Navy and Police helped by residents in the area began the rescue mission, following a public appeal for help from the Pearl Protectors Organisation and Sri Lanka’s leading Marine Biologist Dr. Asha De Vos. In a matter of hours, many other volunteers joined in the race against time to save the distressed whales.
However, this was no easy task said Dr. De Vos. “Rescuing these animals is not just about rolling them out to sea again. It’s a little more complicated than that. It’s important to refloat the animals as soon as possible and guide them back to deeper waters or they will keep getting pushed back to shore. This causes them to fatigue. If they end up on the beach they must be kept wet and their blowholes must not be obstructed.” According to de Vos, if the whales lie on the beach for more than a few hours, the animals are “as good as dead.”
“The weight of their bodies will crush their organs in the absence of the buoyancy of the water. In this case, the animals often need to be euthanised,” she said. The fatigue of the rescuers during the effort to push back the mammals that can weigh between 1000 - 3000 kg also had to be factored in.
The rescuers also faced more challenges as darkness set in. The beach lacked adequate lighting for the rescue mission that would have to be continued overnight if the whales were to be rescued alive. This is when Team IRONMAN 4x4 stepped in by lending their off-road jeeps to the rescue efforts. The jeeps of the team’s members lit up the area allowing for the efforts to continue into the early hours of the morning.
Following the grueling overnight rescue, the efforts of the rescuers were praised the world over. They were even commended by the Sri Lankan President himself. Releasing a statement, President Gotabaya Rajapaksa said “I’m grateful for the Sri Lanka Navy, Police, Coast Guard, Wildlife Department, Villagers and other voluntary organisations who worked tirelessly to rescue more than 120 pilot whales off the shallow shores of Wadduwa, Panadura recently” he said. Rajapaksa called the efforts of the rescuers and volunteers a great act to demonstrate to the world the virtue of non-violence rooted in Sri Lanka.
While the rescue mission was hailed as a success, concerns among the public remained about the cause behind the mass stranding. Many appeared to think this could be perhaps a sign of something far more dangerous such as a tsunami.
Dispelling fears
But dispelling these unfounded fears Dr. Asha De Vos putting up a post on her social media account said pilot whales are a species known to strand for reasons not fully understood. In the post, De Vos wrote “We experienced a stranding event on the east coast a few years ago and in September 2020 Australia witnessed the largest pilot whale stranding event in its history with an estimated 470 whales stranding. Sadly not all survived.
Why do they strand? We don’t fully know. But scientists assume it’s because of their highly social nature. If one animal strays too close to the coastline and gets pushed onto the beach by the waves, there is a high chance the others will follow.”
According to the General Manager of the Marine Environment Protection Authority (MEPA), Dr. Terney Pradeep Kumara, they may have been suffering due to nitrogen saturation. Kumara said the whales had shown signs of the effects of a deep dive probably forced by encountering ships using sonar. “These whales navigate using sonar and when they encounter shipping which is also using sonar tend to dive deep to escape,” he said. If they dive as deep as a kilometre they become saturated with nitrogen, a condition that deep divers sometimes get called ‘bends’ he added.
Environmentalist Nayanaka Ranwella said that he believes the Malabar Military Exercise, a naval joint exercise of India, the United States, Japan and Australia in the Indian ocean ( which kicked off this week) could have led to the mass stranding due to the sonars of the military naval vessels.
In fact, scientists have repeatedly called for a wide-scale ban on the use of sonar to protect whale populations after a study highlighted a link between the military sound pulses and mass strandings in which dozens of the mammals have died.
Sonar ban
Marine biologists have long warned that the creatures’ senses could be damaged by sonar, with the unfamiliar noises coming from vessels confusing the animals.
Experts said the mammals often attempt to swim away from the sound source, and this leads them to become disorientated.
For deep-diving marine life such as the beaked whale, which was the focus of the study, sonar can lead the animals to ascend too rapidly, causing decompression sickness. Researchers at the University of Las Palmas de Gran Canaria focused exclusively on beaked whales in the seas surrounding the Canary Islands.
They found that a sonar ban introduced there in 2004 had been effective in reducing whale strandings and called for more sites to be established to prevent further deaths, including in the Mediterranean, where beaked whales are listed as vulnerable.
“Animals may respond to stressful situations by exhibiting the ‘flight or fight response’ with increased heart and metabolic rates, often accompanied by fast movement away from the perceived stressor,” wrote the authors of the report.
“We recommend a moratorium on mid-frequency active sonar in those regions where atypical mass stranding events continue.”
Whatever the cause may be behind the recent mass stranding in Sri Lanka,unfortunately not all the pilot whales directed back to sea survived the distressing ordeal. Seven whales and a dolphin have since died and their carcasses have washed back on to the shore. To determine the cause the samples of dead whales that washed up on Sri Lanka’s coast this week will be sent for testing.
Having already conducted an autopsy on the dead whales, Dr. Tharaka Prasad, Director of Wildlife Health at the Department of Wildlife (DWC) said he believes disorientation had caused the marine mammals to the beach.
According to Dr. Suhada Jayawardana, a veterinary surgeon at the Department of Wildlife Conservation more samples will most likely be sent to the Veterinary Research Institute in Peradeniya.
“After sending them for testing we believe that we will be able to determine the reason for their deaths and also why they had beached on the coast,” he said. Despite several deaths, Dr. Tharaka Prasad has called the rescue mission one of the most successful he has witnessed. The authorities had braced themselves for possible mass deaths as seen in Tasmania in September when about 470 pilot whales were stranded and only about 110 of them could be saved after days of rescue efforts. But it was a much happier ending to the mass stranding at Panadura.
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Whale stranding incidents in Sri Lanka
May 2017 - A pod of 20 pilot whales was stranded in Sri Lanka’s northeastern coastal town of Sampur near the Trincomalee harbour. All the animals were safely sent back.
April 2011 - A sperm whale was stranded inside the Trincomalee harbour. Two navy boats were able to guide it out into deeper waters where it was reunited with waiting whales.
