The South Pacific is a vast ocean wilderness.
Its waters are teeming with life...
...from tropical coral reefs that attract the great variety...
to the cooler, temperate waters that attract the great numbers.
So why is it that in the midst of all this richness
the world's largest predators can struggle to survive in this...endless blue?
Nothing brings home the challenges of surviving in the South Pacific better
than the epic true story that inspired MobyDick.
On 23rd February 1821, a lifeboat was found drifting
in the eastern Pacific.
In it lay two American whalemen,
barely alive.
Their whale ship had been sunk by an enormous sperm whale.
For a staggering three months, these shipwrecked mariners had sailed
across 4,500 miles of what may be the loneliest region on Earth.
For these sailors, the South Pacific had become a living hell.
So what is it about this ocean that makes survival here such a challenge?
Of all the oceans, the Pacific is by far the largest,
stretching almost a third of the way round the globe.
It's so huge that the current in the South Pacific
takes several years to complete just one cycle.
In an ocean this vast, many animals have to travel huge distances to survive.
None more so than the sperm whale,
one of the greatest voyagers on the planet.
Every year, thousands of bull sperm whales,
some from as far as Antarctica, come to the tropics to breed.
After 15 years away, fattening themselves up in colder climes,
they are now back and big enough to compete for a mate.
These warm, equatorial waters make ideal nurseries.
At just a week old, this white calf already weighs over a tonne.
For the next six years, he will stay by his mother's side,
relaxing in these tropical waters where killer whales,
his only natural predator, are rarely found.
But it was in these peaceful stretches of ocean that, 200 years ago,
whales met whalemen.
In the 19th century, oil from the whales' massive heads could make great fortunes.
Whalemen targeted the calves first,
knowing the rest of the pod would soon come to their aid
...and into the range of the harpoons.
But for one ship, the whales got their revenge.
Without warning, a huge bull rammed the hull of the 87-foot Essex.
Within days, the broken ship was lost to the deep.
With their ship gone,
the 21 survivors squeezed into three whaleboats,
which now became their lifeboats.
The men salvaged what they could,
but they were woefully ill-equipped for the trials that lay ahead.
The survivors of the Essex were in virtually unexplored waters,
2,000 miles west of South America on the equator,
almost as far from land as it's possible to be.
They were about to find out
just how challenging survival in the South Pacific can be.
Unable to sail directly east because of the prevailing winds,
they were forced south and into the area of the South Pacific
known then as the Desolate Region.
A vast, uncharted, windless ocean the size of Australia.
These beautiful blue waters are the clearest in the world.
But they are a watery desert,
clear and blue because there is so little plankton,
the key to all marine food chains.
Plankton need nutrients, but most nutrients are locked in the deep,
denied access to the surface by a layer of water called the thermocline,
around 200 metres down.
The little life that does exist at the surface seeks shelter,
no matter how superficial it may be.
In time, whole communities build on the flotsam.
Barnacle larvae settle,
along with miniature predators.
Frogfish.
On just a piece of drifting rope,
tiny creatures may spend their entire lives.
Three weeks on, the shipwreck survivors
were in the heart of the Desolate Region.
And in deep despair.
In the boat's log, one of the survivors wrote,
"The violence of raving thirst
"has no parallel in the catalogue of human calamities."
They had almost run out of rations,
and despite being experienced sailors, failed to catch a single fish.
But there are pockets of richness in the South Pacific.
One was well known to the crew of the Essex
and would have been in their reach, but for the prevailing winds.
Lying over 700 miles off the coast of South America are the Galpagos Islands.
Unlike the open ocean, the seas surrounding these 100 or so islands
are bursting with life,
with many creatures you wouldn't expect to find
in tropical seas, like these sea lions.
Despite sitting on the equator,
the waters around the Galpagos are cooled
by currents flowing all the way from Antarctica.
It is this that allows the Galpagos to be home
to the world's only tropical penguin.
Tropical fish live here, too.
Thanks to the nutrients carried by the cool current,
there is an abundance of life.
Unlike the open ocean,
the water here is rich in plankton, feeding huge shoals of fish...
...and even giant manta rays.
Each sea lion needs over 6kg of fish a day.
With shoals this size, it shouldn't be too difficult.
But it's not easy picking one fish out of the crowd.
The fish know there's safety in numbers, so for the sea lions
the trick is to snip the shoal into smaller and smaller balls.
Finally, a fish breaks for cover. It's what the sea lions have been waiting for.
Crevices in the reef might seem to offer shelter.
But that's no problem for the sea lions,
who simply scare them out with bubbles.
With the sea lions distracted, the fish regroup
and the chase starts all over again.
The riches of the Galpagos
were something the survivors of the Essex could only fantasise about.
One month into their ordeal, and still adrift in the Desolate Region,
they were slowly starving.
What the sailors didn't know was that the endless blue hides a secret.
At dusk, huge areas of otherwise empty ocean are transformed.
Squid shoot up from the depths to feed near the surface.
Surprisingly, there are more squid in the ocean than fish...
...and they take part in the greatest migration of animals on the Earth.
Every night, a world of creatures
rise up from the depths to dine on the small amounts of surface plankton.
They are among the strangest-looking life forms on our planet.
In this dark world, some are see-through, perhaps for camouflage.
Some create their own light to communicate or lure in their prey.
Others form inexplicable alliances.
This young slipper lobster
may be using this jelly as a buoyancy aid.
Some of these ocean vagrants may offer protection,
like this pyrosome is doing for the shrimp.
In the world's deepest ocean,
averaging over two-and-a-half miles deep,
new species are constantly being discovered.
Like this seahorse, never filmed before.
At dawn, these little-known creatures
retreat into the safety of the abyss.
But there are some predators that can follow them down.
Short-finned pilot whales are accomplished deep-sea divers.
Leaving the barren upper layers behind, they can swim over half a mile down
and use their sonar to track the huge shoals of squid.
But they too are being tracked.
Oceanic whitetip sharks, three metres long,
and completely at home in the open ocean.
They may not be able to dive deep enough to catch the squid themselves...
...but that won't stop them hanging around for scraps.
Or maybe they're sizing up the calf.
This one, however, is well guarded
by the bulls.
But in the endless blue, where the odds of finding a meal are so low,
even the slimmest opportunity is worth a try.
Perhaps this is why the oceanic whitetip is thought to be responsible
for more attacks on shipwrecked sailors than any other shark in the Pacific.
The survivors of the Essex were at the mercy of sharks.
As one sailor wrote,
"Our utmost efforts, which were at first directed to kill him for prey,
"became, in the end, self-defence."
Now, more than ever, they needed the salvation of land.
Seabirds would have been a ray of hope.
While tropic birds can survive at sea for months on end,
others, like frigate birds, return to roost every night,
so are a sure sign of nearby land.
Guided by the sun, stars and the Earth's magnetic field,
seabirds navigate over thousands of miles of featureless ocean.
They must all return to land to breed,
often on little more than dots of sand,
which makes their navigational skills even more impressive.
The greatest ocean wanderer, with its two-metre wingspan,
is the albatross.
To find enough food for its oversized offspring,
this black-footed albatross may have travelled a staggering 6,000 miles
across the open ocean looking for hotspots of squid and fish.
The albatross nest
on the tiny Hawaiian islands of French Frigate Shoals.
This island may be only half a mile long,
but it provides a base for around 300,000 seabirds.
With food so hard to come by in the open ocean,
newly-hatched sooty tern chicks are easy pickings
for the larger frigate birds.
For hours on end, they survey the nesting ground...
...waiting for a chance to strike.
A mother tries desperately to protect her helpless chick.
But an unguarded chick is desperately vulnerable.
It's what the frigate has been waiting for.
No wonder the crew of the Essex called them the Man of War birds.
For two weeks, the frigate birds keep up their relentless aerial assault
until finally the sooty tern chicks are old enough to get away.
Tropical islands are an obvious magnet for life.
But things are just as busy underwater.
Deep currents collide with these islands,
forcing small, but vital, amounts of nutrients up from the depths.
At 50 metres deep, sea fans are amongst the first to benefit.
Closer to the surface, corals have sunlight to help them grow.
And thanks to the smallest trickle of nutrients,
a barren desert can bloom into an underwater oasis...
...supporting a greater variety of life than any other ocean habitat.
These coral reefs are a magnet for green turtles,
offering a service not available in the open ocean -
a good clean-up by a shoal of tangs.
This work-over is far from cosmetic.
As well as removing parasites,
the cleaning stops the build-up of algae, so the turtle can swim freely.
But it's also got to feel good!
These turtles navigate their way across 1,000 miles of featureless ocean
to reach these tiny isolated islands.
Perhaps they use their super-charged sense of smell
to detect the traces of land in the ocean currents.
Or maybe, like the seabirds, they too have an internal magnetic compass.
But however they do it, when they're ready to nest,
the females return to the very same beach on which they were born.
Just as she arrives, others are preparing to leave.
These seven-month-old black-footed albatross chicks
have recently been abandoned by their parents.
And now, driven by hunger, it's their time to get airborne.
Unfortunately, with space at a premium, there is little room for manoeuvre,
and they must make their maiden flights over water.
But this is no place for a paddle.
Tiger sharks.
A dozen sharks, each over three metres long,
have crossed hundreds of miles of ocean to attend this annual feast.
Uncannily, these fearsome predators often arrive on the same day
as the first chicks take to the air.
Nothing could've prepared these chicks for such an encounter.
Yet, despite looking like sitting ducks,
inexperienced sharks find them hard to sink their teeth into.
In an ocean where food is so hard to come by,
the sharks can't afford to keep missing.
They must quickly perfect their technique.
For these albatross chicks, running the gauntlet of sharks
may seem an impossible challenge,
but the vast majority make it to a life in the open ocean.
Specks of land were just as vital to our shipwrecked survivors.
Not that they were easy to find.
Only 1% of the Pacific is land.
On the 20th December, the sailors arrived on the Pitcairn Islands,
over 2,000 miles from where they were first shipwrecked.
Described by them as "a paradise before our very eyes",
the starving sailors quickly set to work on the island's wildlife.
But the good times were not to last.
Within a week, they'd eaten all its seabirds.
Leaving three of their group behind on this now impoverished island,
the others chose to take their chances back at sea.
They could've ridden the prevailing winds to the nearby Society Islands,
but they were terrified of cannibals.
Instead, they struck out east, to the distant shores of South America,
2, 500 miles away...
...and back into the dreaded Desolate Region.
Bull sperm whales also undertake epic voyages across the Pacific.
To reach such a gargantuan size,
young bulls must leave their family groups in the tropics
and go in search of richer pickings.
And so they head for the temperate seas of the higher latitudes.
Crossing thousands of miles of ocean,
many voyage to one of the greatest feeding grounds in the South Pacific -
New Zealand.
Its two main islands span almost 1,000 miles,
and journeying south, its coastal waters become progressively cooler
and weather-beaten.
At 40 degrees latitude,
severe westerly winds known as the Roaring Forties blast the coastline.
Yet, it is the foul weather that produces the abundance of life
found in these cold waters.
Storm-churning and colliding currents
unlock the deep's great reserve of nutrients and send them to the surface.
In these temperate seas, corals are replaced by forests of seaweed.
In the summer, giant kelp can grow a staggering foot and a half a day.
These waters may not support the diversity found in coral reefs,
but they boast a far greater volume of animals.
And a lot of fish means a lot of fish-eaters.
Dusky dolphins off the coast of Kaikoura
in New Zealand's South Island are so well fed
that they can form superpods a thousand strong.
After their epic journey from the tropics,
the young bull sperm whales have finally made it.
Sperm whales dive deeper than any other whale.
They are drawn here by the fabulous wealth of deep sea creatures.
Even the giant squid that lurk in the depths of a vast underwater canyon.
To dive so deep and remain there for over an hour,
whales must spend around ten minutes
filling their lungs and blood with oxygen...
...much to the interest of a passing fur seal.
These young bulls will now spend another 15 years bulking up
in the nutrient-rich seas.
Only when they have become 30-tonne giants will the largest predators on Earth
finally return to the tropics to compete for a mate.
200 years ago, on the other side of the South Pacific,
the journey of our whalemen was coming to an end.
94 days after the ship was scuttled by a sperm whale,
one of the whale boats was finally spotted 400 miles off the coast of Chile.
Only Captain Pollard and Ramsdell remained,
gnawing on the bones of their dead shipmates.
17 days earlier, in their darkest hour,
they had drawn lots, executed and eaten them.
Of the three boats that were cast adrift,
two resorted to cannibalism.
One was never seen again.
Navigating and surviving in this vast, remote wilderness
had proved almost impossible for these experienced sailors.
And at times, even the ultimate ocean travellers need help.
Natural harbours may be safe havens for sailors...
...but for the migratory whales, they can be death traps.
A pod of 12 bull sperm whales has become fatally stranded.
Was this stranding caused by one whale making a navigational error?
No-one knows.
But with social bonds so strong, the other whales can't help but follow.
One whale is still alive,
but without sufficient water to support his incredible bulk,
his internal organs will be crushed.
Left like this, he will die within days.
Thankfully, our attitude to sperm whales has changed
from exploitation to conservation.
So, a rescue team tries to dislodge him with waves from the bow of their boat.
But he's held fast.
His sunburnt skin quickly blisters.
The only option left is to use nets.
At last he's free.
Badly weakened, he's chaperoned towards the harbour entrance.
But he's not out of trouble yet.
First, he must negotiate the rocky heads of the bay.
His sensitive skin, never designed to touch rock, is badly lacerated.
He's through,
and back into the safety of the endless blue.
The sperm whales' story sums up the difficulties of surviving
in this world of extremes.
They succeed, thanks to their great stamina
and extraordinary design.
But at times, even the whales struggle to cope with the challenges
of this vast ocean.
Tiger sharks.
They're one of the Pacific's most formidable predators.
The goal was to film them hunting from above and below the water.
This proved to be the team's greatest filming challenge.
To film this behaviour,
the team sailed 800 miles to one of the remotest islands in the Hawaiian chain -
French Frigate Shoals.
We should just pass...
The timing was critical.
For just two weeks a year,
a dozen tiger sharks gather round this tiny island
ready for the albatross chicks' maiden flights.
So as not to disturb the bird colony,
a scaffold tower was erected offshore
in the middle of the shark-infested lagoon.
This small filming platform was going to be the topside crew's base
for the next ten days.
A daunting prospect for landlubber cameraman John Aitchison.
It's pretty scary being out here when they're really close.
Sometimes the platform wobbles when the waves hit the back of it,
and I do wonder about what would happen if I fell in.
From this vantage point, producer Mark Brownlow was able to spot the sharks
and direct the dive team to the action.
Although experienced,
cameraman Richard Woolocombe was understandably anxious.
I have never dived with tiger sharks.
And I'm incredibly excited on the one hand to see tiger sharks,
but also somewhat reticent, knowing they have such a dangerous reputation.
So shark expert and photographer Doug Perrine was hired to watch his back.
And in one hand, I'll have an aluminium camera housing,
and in another hand, I'll have this high-tech shark billy.
And then it's just a matter of giving them a little poke
to let them know that you're alive and capable of defending yourself.
The moment of truth had arrived.
Bird on the water, 80 yards to the right.
It was time to swim with tiger sharks.
Pulling the boat up at a respectful distance from the bird,
the divers' final approach was from underwater.
To stop any surprise attacks from a shark beneath them,
they hugged the sea bed.
But the bird was long gone.
They waited back-to-back for a tiger shark to show.
None did.
But as they surfaced,
a shark appeared.
Right behind you! Shark, right behind you!
It's a pretty intimidating sight to see a shark that big and that fat.
It's huge girth, absolutely incredible girth.
Standing on his platform, John was perfectly placed to cover the action.
But would Richard be quick enough to get to the birds before the sharks?
Oh! Ohhh!
Just a fraction earlier, we might've got the shot.
This one's moving out towards it now.
- The bird didn't fly off, he got eaten. - You're joking!
With their highly-tuned senses, the sharks were onto the chicks in seconds.
Oh, man! We got so close!
While the dive team lagged behind, John's success continued.
That's it. Oh, no, it's got away!
Shark came up and it's got away. Flying off.
That was a lucky albatross!
Each day, by mid-morning, the activity levels dropped.
The birds stopped flying and there was no sign of the sharks.
In the down time, the topside crew got the chance
to get better acquainted with some new friends.
I just think it's such an honour when birds treat you as a perch!
But I'm quite glad it's not an albatross!
The following day, it began to blow.
The strong wind's really helping them.
It's given them enough lift to take off and carry on flying to get back in.
Oh, no. No...
While unseasonal winds were good news for the birds,
they made Richard's task much tougher.
They're just taking off too much at the moment.
This wind is too strong.
It's not allowing us the time to get to the birds,
or the sharks to get to them.
After the wind came the rain.
More bad news for the crew.
But not for the chicks, who seemed invigorated by the downpour.
The weather cleared up,
but there was a new problem.
A big tiger shark came in.
From your perspective, I think you could see him more clearly than I.
It was so poor visibility down there that I could just make it out,
but I could see it was a pretty big one.
Visibility's gone down to about five feet. That's just not safe enough
to dive with these big tiger sharks. We're gonna have to call off the dive team.
Very disappointing.
The poor underwater visibility
didn't seem to stop the sharks from finding their prey,
giving John some concerns.
I've got very mixed feeling about this,
because I don't really want to see the albatrosses eaten,
but that's what I'm here to film.
You can't help wishing the albatrosses will get away each time.
I sort of cheer inside when they do. There's a shark, right in the shallows!
John continued to film the action.
But it was another three days before the visibility cleared sufficiently
to make diving safe again.
After days of practice,
Richard was finally getting to the birds ahead of the sharks.
Yet, still no success.
What did you see?
The albatross gave us the run-around for a while,
and then he finally decided he'd had enough of us and flew away.
But why didn't the sharks take the bird?
Were they now avoiding the divers?
Whatever senses they're using, they've shown us they want to stay away from us.
Over the next two days, Doug's theory was confirmed,
and Richard realised he had little to fear.
The sharks are not interested in us.
They're only interested in a slightly oilier substance
in the form of a nice, fat, juicy albatross.
I've got a very positive feeling about today.
Conditions are improving. Lots of sharks around,
come to...close to the boat. I think they're inviting us in.
But filming a successful strike from underwater required a different strategy.
No longer worried about being hit from below,
Richard and Doug opted for the quieter approach of snorkelling at the surface...
...only going under at the final moment.
Would this new technique work?
From the surface, the signs were good...
Oh, whoa!
...and John was once again following the action from his platform.
So, how did it go for Richard?
Unbelievable!
That happened in a second!
It was out of nowhere!
My first hint that something was happening
was when I saw a bunch of bubbles around the bird.
Then, I could kinda see the shape of the shark.
That is THE most astonishing thing I've ever seen.
But there was more to this story.
You know, you've got this incredible predator
who's lurking around and you know he's out there.
You know this animal is circling you. You can't see it, it can see you.
And so, you can't help now and again just to look away for a second,
and in that split second on this occasion that I looked away, the shark hit.
The power of the animal as it took the albatross
was on the one hand terrifying, but on the other hand
completely transfixing.
I think that shot's going to haunt me for the rest of my life.
Richard may only have filmed half the strike,
but in the end, given the nervousness of the sharks,
he was lucky to get even that.