Six whales that got stranded in southwest Australia just a day after being rescued from another beach have died, a conservation official said on Thursday. Veterinarians shot three of them, while the others died naturally.
The six long-finned pilot whales that died on Wednesday were part of a pod of 10 that rescuers guided back out to sea on Tuesday. But less than a day later, surveillance aircraft spotted the six on a beach about four miles away from where they had been released. Two were already dead and one died while environment officials and veterinarians were on the way to the area. Veterinarians shot the remaining three surviving animals because they were in such poor condition. The whales were too large for lethal injections.
"It's obviously disappointing," Western Australia state conservation department officer Aminya Ennis said. "But we understand that (the whales getting stranded again) was always a possibility."The other four whales from the pod of 10 are believed to be still at sea. The department would continue to monitor the coast and the ocean to verify their safety.
The whales were part of a group of about 90 whales and five bottlenose dolphins that became stranded on a beach in Western Australia state early Monday. Most of the animals died, but rescuers were able to push four dolphins and four whales out to sea at the stranding site and truck 10 surviving whales overland to deeper waters Tuesday. This week's mass beaching was the fifth in Australia in as many months; nearly 500 whales have died.
Scientists say the types of whales that beach themselves are extremely social groups that follow pod members into danger. But they cannot explain what draws the deep-sea animals so close to shore.The possible theories are many. The whales may be chased by predators such as killer whales, or they could be following prey themselves. The sonar they use to navigate the dark seas could be hindered by natural geomagnetic factors such as iron ore deposits.Human activity such as undersea exploration for petroleum or the sonar of submarines can also interfere with whale and dolphin navigation.
They also show traits of following one ill or injured pod member."Certain species of whales are more prone to mass strandings because the social bonds between them are incredibly strong," said Mike Bossley of the Whale and Dolphin Conservation Society. "If one animal is in trouble, the others won't leave him." Once stranded, some are battered by rocks and surf, while others die of overheating or have their organs crushed by their own body weight after leaving the buoyancy of water.
The mass strandings occur most often in the island state of Tasmania, in Australia's southeast, and in Western Australia.