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Military op in Bay of Bengal may have disoriented pod of whales
Tissue samples were collected from the dead whales to test for pathology, said A Navaratnerajah, National Aquatic Resources Research and Development Agency (NARA) Chairman. The disoriented mammals mostly became stranded together on Monday.
Six whales were washed onto the Panadura beach near the estuary, and Wadduwa. Four whales and a spinner dolphin were found dead on Tuesday and another two carcasses were found the next day.
Whales communicate through echolocation by emitting clicks and squeaks, Prof Navaratnerajah said. They could get disoriented if submarine signals are emitted at a frequency below 14 to 20 khz. Short-finned pilot whales, locally known as “kommaduwa”, is a species that is commonly involved in mass stranding.
These whales grow to an average of 3.7 to 6.0 meters and weigh about 1000 to 3600 kg, Prof Navaratnerajah explained. They live in the deep sea and dive to depths of 1,300 meters. They are capable of short bursts of speed of 32kmph. And they feed primarily on squid and small fish, hunting prey by pursuing them at high speeds. The species moves inshore when travelling the West coast of Sri Lanka.
The rescue operation underway. Pix by Lahiru Harshana
Deaths of such whales could occur when people try to push them back into the sea, as their blowholes (respiratory openings) are blocked with sand and water, the Prof said. The dolphin carcass found in Wadduwa was around three to four days old.
The highly social pilot whales are sensitive to sonar and magnetic fields, said Terney Pradeep Kumar, General Manager of Marine Environment Protection Agency. There could be a mass beaching if something upsets their behaviour.
“We suspect there could have been military operations that disoriented them,” he said. “But we cannot directly say that they beached as a result of such an operation but there have been cases abroad where it happened after these incidents.”
Suhada Jayawardena, the veterinary surgeon in charge of the Western Province for the Department of Wildlife Conservation (DWC), also suspected disorientation due to sound disturbance from a military operation. He carried out a post mortem which showed abnormalities in the whales’ lungs and liver. The colour of the organs also showed signs of pathologies, he said, and some samples were shared with NARA.
But Tharaka Prasad, Director-in-Charge of Wildlife Health, said most whale deaths are likely to have occurred due to stress and fatigue as they attempted to swim back to sea.
“We initially learned that most of the dead whales had external wounds as they had banged against rock and sand,” he pointed out. The post-mortem also revealed their lungs to have been filled with water, as the stranded whales had been in unnatural positions, causing sand and water to enter through their blowholes and cause respiratory difficulties.
The animals also had no food in their digestive tracts. Whenever they are disoriented, they stop feeding and keep moving, Dr Prasad said. Some locals thought the whales were fish and tried to keep them submerged while pushing. This also hindered with their breathing.
| SL could benefit by International co-operation Hiran Jayewardene, a leading proponent of marine affairs and mammal management, said that Sri Lankan efforts to determine the causes of death, stranding of marine mammals and harm to the marine ecosystem could be assisted and strengthened through promotion of international co-operation. The National Marine Mammal Programme of the 1980s should be re-activated as an inter-ministerial programme at the highest level as there is a need for multi-agency capabilities to be marshalled for effective management, Dr Jayewardene urged. Please inform me of these events, urges whales expert Asha de Vos
Dr de Vos only found out about the stranding in the evening as she had not been notified. But she and her team rushed to the site thereafter. “These are pilot whales,” she wrote on the Oceanswell Facebook page. “A species known to strand. 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?” she continues. “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.” Rescuing these animals is not just about rolling them out to sea again, Dr de Vos points out. They need to be refloated as soon as possible and guided back to deeper water or they will keep getting pushed back to shore, causing them fatigue. If on the beach, they must be kept wet and their blowholes unobstructed. “These are not things that everyone realizes, so asking an expert or involving and expert, is always a good idea,” she observes. “If they 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.” “I ask you all repeatedly, if you hear about these events, contact me,” she urged. “My team and I can help. This is what we are trained to do. This is why I exist. While the authorities may have it under control, we don’t have experience in this area and so a little advice goes a long way or it’s just too little too late.” Dr de Vos described the rescue on Monday night: “They were working in darkness, apart from the lights of a bunch of 4×4 vehicles who turned up to help. The moon was behind clouds so we had no real natural light to work with. These people cared less about their own safety in the crashing surf than the safety of these animals, in a very difficult time in our planet’s history. “The whales were stuck in a treadmill. They would be guided past some of the crashing waves, but they were weakening and the waves would push them back. Then the process would start again. I got in the water to help after I had done what I could to guide and explain what needed to happen. Everyone was receptive to the information and were happy to learn which means we will be better prepared next time.” Whale of a job to save the mammals Fishermen, animal rights activists, lifesavers and coastguards carried out a massive operation to save a pod of more than 100 short-finned pilot whales that beached on Monday. They first learned about the stranding around 3.30 p.m., said Chamindra Pinto, Headquarters Inspector of the Panadura police. Fishermen notified them that “kommaduwa” fish had been washed ashore along the Panadura coast. Two officers sent to check soon requested back-up saying a large number of black whales had been washed ashore and were struggling to get back into the seas. More police were quickly deployed. It was a sad sight, said CI Pinto. Fishermen struggled to push the animals back but couldn’t shift them off the sandy beach. Police also had to chase away onlookers and use loudspeakers to urge people to wear masks. “The fishermen didn’t wear masks but their efforts were admirable,” he narrated. “Our officers also joined them in uniform. At least 20 people were needed to push back one whale.” As night fell, the coastguard, activists, environmentalists and others piled in to help. They parked their safari jeeps at the beach and used the headlights to illuminate the beach. The navy used water bikes to drag the whales into deep sea. Later, DWC officials, Wildlife Minister C B Ratnayake and other marine protection authorities also arrived. “By then, around 60 to 70 mammals had been pushed back but some were once again swimming ashore as others were still stranded on the beach,” CI Pintos aid. They were all sent to sea around 2a.m. on Tuesday.
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Marine Biologist Asha de Vos, an internationally-renowned expert on whales, recorded some of the events of this week on the social media page of Oceanswell, a marine conservation, research and education organization that she founded.