The Current

Hundreds of whales die on beach, mass strandings remain a mystery

Hundreds of pilot whales are lying dead on a beach in New Zealand after one of the biggest mass strandings in the country's history. Today we ask why large groups of whales beach themselves.
Volunteers attend to some of the hundreds of stranded pilot whales still alive after one of the country's largest recorded mass whale strandings, in Golden Bay, at the top of New Zealand's South Island, February 10, 2017. (Anthony Phelps/Reuters)

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A mass stranding of more than 650 pilot whales along the tip of New Zealand's South Island has sparked questions about why whales beach themselves.

David Lusseau, professor of behavioural biology at the University of Aberdeen, tells The Current's guest host Laura Lynch that this is a "unusually large mass stranding." 

Local authorities and volunteers have been working hard since Friday to save some of the whales, but as a clean-up operation began on Monday, more than 350 whales had died.

More than 200 whales were able to refloat themselves and swim away while volunteer rescuers were able to rescue and refloat 100 other whales. Despite these efforts to refloat the animals, a portion of those of whales eventually returned to shore again.

"You know and we have to really give our thanks to all the Department of Conservation staff and all the volunteers that been at Farewell Spit over the weekend to try to to help as many to survive," says Lusseau. 

It was the third largest mass stranding in New Zealand's history and the country's largest in living memory.

Why are mass strandings a mystery?

"We cannot be sure about anything," says Lusseau. "We know that mass stranding and strandings can happen for many, many different reasons."

Lusseau says there are a lot of scientific hypotheses, but no simple answer for why so many whales will beach together.

"We have a lot of ideas. And I think the reason why it is so hard to really comprehend it is because actually it's likely that all these hypothesis are right and it's really just depends on each mass stranding what has happened," he says.

In some cases, the reason is simple. "Sometimes some whales are sick and others are following the sick one and the whole school strands."

Can it be stopped?

According to Lusseau, it is unlikely that human intervention could prevent mass strandings of this magnitude from occurring. He says the best way to help is to be prepared to react in the event of a stranding – and know the importance of on-site triage.

"Essentially, you know, if you get to a live whale you have to make a very quick assessment whether it's worth trying to refloat or whether you have to help it."

Listen to the full conversation at the top of this web post.

This segment was produced by The Current's Shannon Higgins.