On Friday, Australian rescuers raced against time to rescue the last surviving pilot dolphins on a beach in Tasmania, where about 200 of their fellow dolphins breathed their last.
Fewer than a dozen of these black and shiny mammals, also called pilot whales, are still alive, according to authorities in the southeastern island state of Australia. About 30 of them were released into the ocean on Thursday, but some were stranded again.
“The priority remains rescuing and refloating animals that are still alive,” said Brandon Clark of the Tasmanian Parks and Wildlife Service.
He told reporters on site that three pilot whales have not yet been found because they are too far from shore and due to difficult tidal conditions.
The next step, he said, would be to remove the carcasses, as if left in shallow water or on a beach they could attract sharks or transmit disease.
Marine wildlife experts sent to the beach have been working Friday in cool rain on their difficult rescue operation, which has been ongoing since Wednesday when the animals were discovered.
A tractor equipped with a fork was used to drag the carcasses of dead pilot dolphins along the coast, now lined up with their tails pointing towards the freezing ocean.
“Gorgeous and smart”
A long white rope connects dozens of dead pilot whales to each other so they can be towed out to sea and dropped.
Weather forecasts show the “best opportunity” to do so will be on Sunday, Mr. Clark said.
As for the surviving animals, employees of Petuna Aquaculture, a marine farming company in Tasmania, helped release them back into the sea.
“It’s very sad to see these beautiful and intelligent animals on land where they shouldn’t be,” Defa Mideke, Petuna’s chief strategy officer, told AFP. “We will go all the way to also remove the unfortunately non-surviving whales.”
Two years ago, Macquarie Harbor, where the phenomenon occurred, was already the scene of another massive stranding involving nearly 500 pilot dolphins.
By that time, more than 300 of them had died, despite the efforts of dozens of volunteers who fought for several days in the icy waters of Tasmania to free the animals.
The reasons for these large twists are unknown.
The researchers speculated that they might be caused by groups of cetaceans huddling too close to shore after feeding. These pilot whales, which can grow up to six meters, are very sociable animals and can follow members of their group who are lost and in danger.
This sometimes happens when old, sick or injured animals swim ashore and other cetaceans in the group follow them, trying to respond to distress calls from trapped animals.
Other researchers believe that gently sloping beaches, such as those in Tasmania, interfere with pilot dolphin sonar and trick them into believing they are on the high seas.
The event comes just hours after a dozen young sperm whales were found dead, also stranded, on King Island, between Tasmania and mainland Australia.
The cause of death for the sperm whales could be an “accident,” as biologist Chris Carlyon of the Tasmanian Conservation Agency reminded the local Mercury newspaper a few days ago.
It’s “the most common reason for stranding,” he explains. “Perhaps they were looking for food near the shore … they could be caught at low tide.”
Stranding is also common in New Zealand, neighboring Australia. According to official figures, about 300 animals fall ill every year.
In 2017, about 700 pilot dolphins washed up on the coast of New Zealand.