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Why do whales beach themselves?

Rescuers say the noise is the hardest part. When whales are stranded on a beach, they keep calling to one another. Others will come in from safe water and join their dying pod.

Whales and orcas move through life alongside family and friends, as humans do. But instead of GPS, they navigate using sound through echolocation, even in the empty darkness of the deep. Sometimes, something throws off their well-honed sonar and leads the whales astray, to where they were never made to go: land.

Why whales beach themselves is still largely a mystery, even after centuries of recorded strandings. But as humans deplete fish stocks and make noise of our own in the oceans, as water temperatures rise and ocean currents change, these events seem to be happening more and more.

On September 21, about 280 pilot whales were found beached in Tasmania’s remote and treacherous Macquarie Harbour inlet. Two days later, aerial surveys discovered 200 whales 10 kilometres further down the coast, making the stranding the largest in Australia’s history and one of the worst on record. By September 25, the fourth day of rescue efforts, about 350 whales had already died, 88 had been returned to sea alive and crews were still fighting for 20 others deemed healthy enough to survive.

For the whales themselves, marine biologist Olaf Meynecke describes a mass stranding like this: imagine trying to find a door in a pitch black room while hearing your loved ones screaming for help on the other side. “When one whale gets into trouble, it calls,” he says. “Like we would, some whales will choose their relatives over their own survival, they’ll try to reach them. The calls they make are very disturbing. They’re not normal calls. You can hear it in their voice, the distress.”

How do strandings happen? What goes on during a rescue? And are we getting any better at saving whales?

(And a warning: this content may be distressing)

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Members of a rescue crew help a stranded whale on a sand bar in Tasmania.

Members of a rescue crew help a stranded whale on a sand bar in Tasmania.Credit:AP

What are the likely causes?

Whales can strand alone, often sick and unable to keep swimming. A sperm whale might wash up with a belly full of plastic. Or animals can strand in groups, as commonly happens with pilot whales and other orcas such as killer whales. The biggest on record involved more than 1000 pilot whales in New Zealand in 1918.

Marine scientist Vanessa Pirotta says there are plenty of theories, from misadventure to navigation errors. Food shortages could be to blame, forcing whales to travel into less familiar waters to hunt prey closer to shore, as could a flight from predators, poor weather or changes to the nutrient-rich sea currents that whales follow around the world.

Others have pointed to earthquakes, solar flares and underwater military sonar, believed to throw off the whale’s echolocation. When it comes to big events, experts theorise it could also be a case of “follow the leader” taking a wrong turn. Perhaps a sick or confused matriarch wanders into dangerous waters.

But Meynecke notes a pod that numbers in the hundreds is not typically led by one leader. “Pilot whales do form bigger groups than a lot of other whales, but they’re not in their hundreds all the time together, usually they have a core group, about 20 or 30, and they come together as a big pod to mate, sometimes to hunt.”

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It’s like high school, he says: there are cliques. And that means mass strandings of this scale happen in more of a chain reaction than one mad rush.

“They never all beach together, some come in and then later, hours, even days on, more come.”

In this case, he says, many subgroups may have come together and the leader of one, perhaps confused or starving, may have led her own companions astray. “Those whales might be close to some in another subgroup, so those ones come and then others won’t leave them, so they come, one after the other, until there’s chaos.”

Pilot whales, he says, are “the masters of strandings”.

“You might have one or two humpbacks but with pilots it’s often whole groups.”

Workers cover a beached pilot whale (but not its blowhole) to keep the sun off as they attempt to rescue it after a mass stranding at Marion Bay, Tasmania, in 2005.

Workers cover a beached pilot whale (but not its blowhole) to keep the sun off as they attempt to rescue it after a mass stranding at Marion Bay, Tasmania, in 2005.Credit:Getty Images

How does a huge whale even get onto a beach?

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Whales do not normally venture into shallow water. There’s no food there, apart from the odd errant squid. But some stretches of coast can trap them in its geography, with waters shifting suddenly from deep water to sand banks and mud. In another very rare event in September, three humpback whales took a wrong turn inland and ended up in a Northern Territory river filled with crocodiles. Two quickly turned back out to sea but one whale travelled upstream more than 30 kilometres before returning safely to the open ocean more than a week later, at high tide, under the anxious gaze of rangers.

“Their echolocation works best when they’re in the open ocean or where there’s hard rocks to bounce off,” Meynecke says. “Sand banks absorb their sonar too fast so they have to get very close to know it’s there.”

By the time the whales realise they have strayed too far, they are already trapped. “They don’t know where to go, or how to get out, they run out of water. They panic.”

Tasmania and neighbouring New Zealand are known hotspots for mass strandings and Macquarie Harbour is notoriously treacherous for boats, let alone whales. The inlet is also remote, making it difficult to get people down to the beach and extra equipment into the water. Nic Deka, of Tasmania’s Parks and Wildlife Service which is running the rescue, said it was unlikely extra resources could have saved more of the animals.

The whales stranded on a sandbank at Macquarie Harbour off Strahan in September.

The whales stranded on a sandbank at Macquarie Harbour off Strahan in September. Credit:Getty Images

Why is it so hard to save them?

Imagine you’re on an alien planet without a spacesuit. You can breathe but gravity is crushing your lungs against your chest, forcing you down to the ground. Not only that but the radiation of the sun is so strong your skin is dry and you’re boiling hot. You don’t know where you are or how to get home. You can’t even move.

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That’s how whales might feel on shore. And from the moment they wash up, they are running out of time.

Whales are marine mammals, they breathe air just like we do, so they can survive periods out of the water. But they are not built for land, they live in the ocean, in low gravity. In the case of larger whales, Meynecke says their bones can break as their own weight crushes them.

During the Tasmanian stranding, drizzly, overcast weather has helped keep the animals cool – even if big swells in the surf did slow down rescue efforts early on. “The sun is always a big problem,” Meynecke says. “Whales can’t sweat, they can’t cool themselves down, and especially these pilot whales, they’re black, they will overheat very fast.”

‘They don’t have hands, they can’t roll themselves over. When the tide comes up, sometimes people have to move them so they can breathe.’

The whales can also drown on the beach if they are leaning with their blowhole underwater. “They don’t have hands, they can’t roll themselves over,” Meynecke says. “When the tide comes up, sometimes people have to move them so they can breathe and you’ll just see this desperate run from one animal to the next, trying to tip them over.”

But the big killer is often stress – chemicals in the body triggered by the animal’s panic will start to build to lethal levels. So rescuers must move fast. The first 48 hours are critical, Meynecke says.

Still, beached whales can be saved. During past rescues, researchers used satellite tags to track those carried back out to sea and found pleasing proof of survival.

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A rescue team at Macquarie Harbour in Tasmania on September 24.

A rescue team at Macquarie Harbour in Tasmania on September 24.Credit:Getty Images

What’s involved in a whale rescue?

In Tasmania, about 60 rescuers have been working to “refloat” the animals off the beach and guide them out to deeper water using slings attached to the sides of boats. It’s a grim and often time-consuming task of triage awaiting rescuers on such a beach, Meynecke says. “You have to assess which animals are too far gone, which can be moved, if there’s a calf, where’s the mother?”

‘Whenever we’ve got live animals that have a chance, and we have the resources, then we’ll certainly give it a go.’

Moving just one whale is exhausting, he says, and there are only so many boats and so many trained volunteers on hand. Usually, teams will need to wait for high tide, where there is more water near the animal. It can be dangerous too, both for the rescuers and their charges, as animals can thrash around.

On the third day of the Tasmanian rescue, about 88 whales had been guided out of the shallows and through Hells Gates, the narrow mouth of the Macquarie Harbour, but most had died. Four had been euthanised, although the tally of 380 dead was later revised down to 350 after some additional live whales were discovered late in the day. Rescue efforts have continued for a calf spotted swimming in the shallows beside its beached mother, following a positive veterinary assessment.

Deka says: “Whenever we’ve got live animals that have a chance, and we have the resources, then we’ll certainly give it a go.”

Wildlife biologist Dr Kris Carlyon says crews are rotating regularly but the job still takes a physical and emotional toll. “It’s pretty confronting. This is such a tricky event … any whale we save we are considering a real win.”

But sometimes they back in.

Why do whales come back after being rescued?

It’s a well-known but heartbreaking phenomenon, now playing out in Tasmania. Whales seem to deliberately re-strand themselves to get back to those still on the shore.

Meynecke thinks the whales know they are facing death and do it anyway. “They want to be together.”

During some rescues, lines of boats or even human chains of volunteers will block off the rescued whales from returning to the shallow waters.

Meynecke said studies of the whales which chose to re-strand themselves do not always reveal a genetic connection between the animal left on the beach and the one that returned.

‘What they hear is a call for help, so it doesn’t matter that it’s not their calf on the beach, they still go.’

“But we know whales and dolphins form life-long friendships just like people, and their families can change. Or perhaps they can’t recognise each other’s calls the same way they can at sea. What they hear is a call for help, so it doesn’t matter that it’s not their calf on the beach, they still go.”

Experts expect the stranding will leave a big vacuum in local pilot whale populations. “It’s not just about genetic diversity,” Meynecke says. Whales carefully hand-rear their young, teaching them not only how to survive, but also, some scientists think, a kind of culture. Imagine whole generations of our parents vanishing in a single tragedy.

But Carlyon says the rescued whales are still likely to recover and regroup further out at sea, even if they have to learn new behaviours. “We hope … they are reforming those bonds again.”

Dead pilot whales on the beach near Strahan in Tasmania.

Dead pilot whales on the beach near Strahan in Tasmania. Credit:Getty Images

Are we getting any better at saving them?

While no tech start-up has yet come up with an easy fix for moving lots of big, heavy animals off a beach, a few innovations are helping speed up rescues (such as inflatable gurneys designed to slide under the whale). Some not-for-profits around the world now train their own whale rescue commandos to deploy when tragedy strikes and Tasmania’s Parks and Wildlife Service has skilled up locals in recent years (sometimes using a blow-up whale named Mark who can weigh up to three tonnes when filled with water).

“It’s getting a bit more co-ordinated, particularly in New Zealand, but sometimes it’s still left up to poor local councils,” Meynecke says. “The cost, particularly of clean-up, can be huge.”

So how do you dispose of hundreds of semi-buoyant whale carcasses? Usually by burying or at least sinking them, authorities say. Letting them float back to sea can create hazards for boats, or rescuers.

Today, the ocean that whales have swum for millennia is being radically transformed – by overfishing, by global warming, by pollution. But Meynecke says one thing has changed for the better: how we see them.

“Even just 200 years ago, people went out in droves to slaughter them. Now, they are turning up on a beach to save their lives, and there’s lots more of us who would do anything to go down there too and help them find their way again.”

With Mary Ward and Laura Chung

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