Officials make ‘hard decision’ to euthanize whales after mass stranding in Western Australia

(CNN) — Wildlife officials in Western Australia said they had to make a heart-breaking decision to euthanize a group of whales who became stranded on a beach after a frantic rescue effort to refloat them failed to yield results.

A pod of almost 100 long-finned pilot whales were first spotted on Tuesday at the Cheynes Beach in the southern tip of the Australian state. By the next morning, local authorities confirmed at least 51 had died.

Video posted to social media shows dozens of the whales – some laying sideways, others on their backs – flapping their tails in shallow waters. Another video shows the whales huddling together, remaining still.

More than 250 volunteers and a team comprising veterinarians and marine life experts joined a rescue mission to try and coax the remaining 45 whales to the ocean.

But the Parks and Wildlife Service of Western Australia said the surviving whales later restranded themselves, with experts concluding that euthanizing them was the best option to “avoid prolonging their suffering”.

Incident controler Peter Hartley, from the Department of Biodiversity, Conservation and Attractions, called the decision “one of the hardest” in his 34 years of career in wildlife management.

“Really really difficult. But it was a considerate and well-thought out decision,” he told reporters on Thursday.

“We know that whale stranding is a natural phenomenon. But we gave it a good go, spending the whole day in the water to give them to best opportunity,” Hartley said, adding how “the conditions were trying” due to the cold water in Australia where it is currently winter.

Long-finned pilot whales, which can grow up to 25 feet (7.6 meters) long, are identified by their black color and bulbous foreheads. They can be found in waters of the Southern Hemisphere and North Atlantic Ocean.

Wildlife researcher Vanessa Pirotta said it remains unknown why the pilot whales became stranded, but noted the pod demonstrated the rare behavior of huddling together prior to their beaching.

“It could be that they are trying to avoid a predator, like a killer whale,” she said.

Pilot whales are “very social and dynamic with strong bonds with others,” she said, meaning they could end up getting lost if they followed a disorientated pod member.

Toothed whales such as pilot whales that use sonar to navigate are more commonly prone to stranding than their toothless counterparts, Pirotta said.

And pilot whale strandings are common across the world.

Last September, around 200 were beached along the coast of Tasmania, Australia. Of that number, only 35 survived and were refloated. Tasmania’s largest stranding was in 2020, when more than 450 pilot whales were found.

Earlier this month, a pod of more than 50 pilot whales died after a mass stranding on a northwestern Scottish island.