About 90 pilot whales have died and another 180 of these cetaceans are still stranded in a remote bay in Tasmania, southern Australia.
The country's authorities launched, Tuesday, September 22, a particularly difficult rescue operation to come to their aid.
Scientists said two large groups of these marine mammals, sometimes called pilot dolphins, had stranded on sandbanks in Macquarie Harbor, a bay closed by a narrow pass on the west coast of Tasmania.
Shallow waters
Videos showed mammals struggling to escape the shallows.
Lifeguards and semi-rigid rescuers were sailing around in an attempt to help them get back afloat.
In some photos, rescue workers in wetsuits appeared standing, waist-deep in water, a few meters from stranded cetaceans.
Most of the cetaceans in a group of around 30 washed up on the beach had already died on Monday.
Another sixty have died since then.
Saving the pilot whales still alive would be a "challenge" that could take several days, especially as approaching them necessarily involves using a boat, said Kris Carlyon, a biologist employed by the government.
Select the animals to save
Strandings of marine mammals are relatively frequent in Tasmania, but this is of particular concern given the large number of animals involved, 270 in total.
About sixty people, including employees of neighboring aquaculture farms, are involved in this rescue operation.
The cold, the humidity and an irregular tidal regime complicates the organization of relief.
According to Kris Carlyon, most pilot whales, which are partially underwater, should be able to survive for several days.
This weather, unpleasant for humans, could work in favor of these marine mammals.
Rescuers will however need to select which animals to save, focusing on those that are most accessible, and those that appear healthier.
Several hypotheses
Scientists are unable to explain with certainty the reasons for these massive strandings.
Kris Carlyon judged it possible that the group strayed into these stumbling waters getting too close to shore to hunt, or that they followed one or two animals that had stranded.
Karen Stockin, a marine mammal specialist at Massey University in New Zealand, said Tasmania has been a frequent ground for pilot whales, a species not considered endangered.
When these cetaceans are back in the water, the other challenge will be to help the band avoid the sandbanks of Macquarie Harbor and return to the high seas.
Although pilot whales are among the most resilient cetaceans, rescuers are in a race against time, she added.
Among the risks, there is the risk that mammals cannot cool their bodies, that their muscles deteriorate or that some of their organs are crushed due to prolonged contact with the bottom.
"Time is never on their side," she warned.
"The faster the rescue operation, the greater the chances of survival."
With AFP
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