Credit: NASA

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It was a scene akin to a war zone. Hundreds of bodies scattered in the surf as the sun rose above the postcard-perfect coastline. Some showed little signs of life, while others cried out for help.

This was the distressing sight for residents of King Island in Tasmania who woke earlier this month to find more than 200 whales and a few dolphins stranded on Naracoopa Beach.

"When we arrived at noon there were 54 pilot whales still alive and five bottle nose dolphins," said Chris Arthur, the Incident Commander at Parks and Wildlife Tasmania.

Arthur has overseen the rescue efforts of four of the mass strandings that have occurred in Tasmania this summer. Most recently, 62 whales and dolphins died this week when they were stranded at Hamelin Bay in WA - bringing the total to more than 460.

Despite advances in science, experts seem at a loss to explain exactly why whales and dolphins beach themselves. After all, aren't they supposed to be intelligent creatures?

Theories abound: is it herd mentality? Illness? Sonar from Navy ships? Changes in weather patterns?

Beached as

What is known is that rescuers need to act quickly to save the animals from themselves.

"The sun is the main problem," Arthur said. "They have low blubber so tend to heat up quickly." The stranding at King Island was a happy ending for Arthur's team with all 54 whales and 5 dolphins making it back to the open ocean, but it isn't always the case.

"Every situation and every beach is different," he said. "You have to work with the weather and with the tide."

Last November, Arthur and his team transported 11 pilot whales 17 km to another beach where calmer low tide conditions allowed the animals to be safely released back into the ocean.

"Animals usually die by being crushed or rolled in the surf and drowning," he explained so properly talking stock of the weather and tide conditions is vital for a successful rescue.

Unfortunately, success is the exception rather than the norm when it comes to mass strandings. Late last year 53 whales died when they stranded at Anthony's Beach and 155 died near Sandy Rocks.

"101 reasons"

It is difficult to pin point the exact reason for each stranding said Ronny Ling, President of whale rescue group ORRCA, which is often the first on the scene of a stranding. "Every time that an animal strands in mass it could be for 101 different reasons," he said.

ORRCA is a non-government organisation that fund a 24 hour, 7 day a week hotline for people to call in the case of a stranding or distressed marine animal. He says most of the calls they receive are for single animals.

"Every part of the coast line in Australia whether it's bays or the open ocean has the potential for an animal to strand," said Ling.

"Normally the open ocean animals are the ones that strand in pods or mass numbers but every species of whale or dolphin has been known to strand singly at least."

Many species of whale and dolphin travel in pods, said Ling, and it's been known for one distressed or ill animal to lead an entire pod into the shore.

"One animal gets into strife and the others come into help it and when they get in strife more animals come in and it sort of pyramids in and then you end up with a lot of animals on a beach," he said.

Catherine Kemper, a marine mammal expert from the Australian Antarctic Division said this was the most likely scenario but that most mass strandings still remain a mystery.

"The reasons for this is probably that these species are not used to being near shore and their social behaviour involves 'following the leader' even if it means to their death," she said.

Ocean currents

Mark Hindell, a marine ecology expert from The University of Tasmania who has been working with marine animals for over fifteen years agreed.

But it's likely that the whales were being brought closer to shore in Tasmania because of changes in the ocean current cycle, he said. Cyclic changes in the oceans currents periodically bring cold, southern Atlantic water closer to Tasmania and bring the whales, specifically pilot and sperm whales close to the coast.

"It's a cycle of about 10-12 years," he explained. "When you are at a peak you will get several years of quite a few strandings and then they will slowly tail off and then they will slowly ramp up again."

Some beaches are more prone to mass strandings because of the place on the migration route and the landscape of the beach itself. Beaches with offshore sandbanks can lead to confusion for whales that suddenly find themselves in shallow water.

"There are some places where there have been multiple strandings over the years and the reason for that is - we are not absolutely sure, but we suspect it is -some beaches are just less safe for whales than other beaches," Hindell said.

Hindell admits that pin pointing a reason for whale strandings is not an exact science. "There's probably as many causes as there are strandings," he said.

Whales have also been known to strand due to illness or disease with toxic algal blooms in California being linked to large numbers of deceased animals washing ashore in the US.

Human causes

There is also the controversial issue of human involvement, particularly defence sonar. According to Kemper, little research into sonar involvement has been done in Australia but it has been linked to strandings in the US.

"Recent evidence from some strandings, particularly the deep-diving beaked whales, shows that low-frequency and powerful underwater sounds can result in animals stranding," she said.

Rosemary Gales from the Department of Primary Industries in Tasmania said the first point of call after a stranding is to investigate sonar involvement.

"Our standard practice is to contact Defence and industry by phone to immediately check if there are exercises in the area of the strandings," she said.

This is the driving force behind current research into whale strandings and other such events.

"Whale's have been standing forever but the initial concern is whether it is increasing," said Hindell.

"There is certainly more human activity that could influence these sorts of things. We want to understand whether or not we are dealing with a purely natural phenomenon or whether there is something else over laying that."