Ocean Sentry
Six whales believed to be part of a small pod that was rescued from a mass stranding in southwest Australia earlier this week were dying on the shore Wednesday after re-beaching themselves, the government said. Two of the long-finned pilot whales were already dead and the others appeared to be deteriorating rapidly, according to a statement from the Department of Environment and Conservation.
The department was sending specialists and veterinarians to euthanize the ailing animals, which were spotted by airplane on a beach almost four miles (six kilometers) away from where a pod of 10 had been released a day earlier.
“We believe they are part of the rescued group from yesterday, so it’s very disappointing” said John Carter, operations officer with the department. “We’ll compare photos and measurements when we can get out there.”
He said they thought the other four rescued whales were safe at sea.
“At this stage we’re assuming they are OK but we’ll be monitoring the coast and waters over the next few days,” Carter told The Associated Press.
The whales were part of a pod 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.
They whales appeared disoriented at first, trying to swim back to shore, but rescuers guided them to deeper waters and the animals began swimming away. Officials had hoped they were swimming to safety.
This week’s mass beaching was the fifth in Australia in as many months; nearly 500 whales have died in those strandings.
Scientists say the species of whales that beach themselves are extremely social groups that follow pod members into danger. But they cannot explain the mass beachings or what draws the deep-sea animals so close to shore.
There are a number of plausible theories: 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. They may swim into an area where sandbars or peninsulas block their exit. Or they may follow one ill or injured pod member and refuse to leave it.
Human activity such as undersea exploration for petroleum or the sonar of submarines also can interfere with whale and dolphin navigation.
Whatever the reason, once one animal heads for the dangerous shallows, the rest are likely to follow.
“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 weightlessness of water.
The mass strandings occur most often in the island state of Tasmania, in Australia’s southeast, and in Western Australia.
(From google.com, by Tanalee Smith)
