(THEME MUSIC PLAYING)
DAVID ATTENBOROUGH: An olive ridley turtle.
She's resting in the shallows off Costa Rica,
having swum a thousand miles to be here.
All because the eggs she carries must be laid on dry land.
Now she's returned to the very same beach
where she hatched 10 years ago.
She must leave the safety of her marine world
and brave the alien world beyond.
She's heavily laden
but the future of the next generation of her kind is at stake.
All along the beach in a spectacle that has remained unchanged
for millions or years,
mother sea turtles emerge from the ocean
in their hundreds of thousands.
Only those animals that overcome the great challenges
of both land and sea
can make the most of life here on the coast.
Our shores are places of sudden changes and rich rewards.
The Galapagos Islands in the tropical Pacific Ocean.
Their barren coastline looks inhospitable,
but one group of animals has learnt to use it to their advantage.
(EXHALES)
(BOTH BARKING)
Sea lions.
Bachelors.
They need to pile on the pounds
as only the biggest males will attract a female and manage to breed.
If these young bulls fail to grow big enough,
they will remain exiled on this isolated shoreline.
So one hungry young bull heads out alone.
He's on the hunt for big game.
Yellowfin tuna.
Each weighing 60 kilos
with a top speed of 40 miles an hour.
He can't possibly catch one in the open sea,
but he has a plan.
Ahead lies the entrance to the cove.
He herds them towards it
into his trap.
Driving them into a dead end.
But they give him the slip.
(BARKING)
He's failed.
(CONTINUES BARKING)
But there might be another way.
Now they head off as a team
to round up more tuna,
driving them back into the cove.
The sea lions fan out channelling the tuna towards the bottleneck.
Once again the tuna hit the dead end.
But this time, the young bull doubles back
to act as a blocker sealing off the exit.
This time when the shoal tries to escape,
he blocks them and drives them back into the next blind alley.
The gang can now pick them off one by one.
This clever fishing technique,
demanding foresight, planning and cooperation,
has only every been seen here in the Galapagos.
Each massive fish provides them with five times more protein .
than a normal day's hunting.
Finally, the young bull leaves his post
to claim his reward.
(SQUAWKING)
On a diet of protein-rich tuna,
he's well on the way to becoming a full-sized breeding bull.
By using this cove,
these Galapagos sea lions have made the most of the opportunities
that occur where the coast's two worlds meet.
Coasts are the most swiftly changing of all ocean habitats
because of the tides.
Tides are created as the moon's gravity pulls at the sea.
As the moon circles our planet, the seas rise and fall.
Typically twice a day,
creating the most constantly dynamic landscapes on Earth.
Nowhere else do sea-living creatures face such changeable conditions.
With the daily risk of drying out and being scorched by the sun.
Where the tide retreats across a rocky shore,
it can leave behind a temporary oasis.
A rock pool.
Seemingly, it's a haven of calm.
But not for long.
Turning minutes into seconds reveals unexpected dramas.
In rock pools, grazers, scavengers and filter feeders
must all make the most of the few short hours
before the tide returns.
Anemones gulp down anything they can reach.
Though some meals are harder to digest than others.
These magical worlds soon become battlegrounds.
A deadly predator with five arms and on the underside a mouth.
The ochre starfish.
And it's in search of limpets.
For some, there is no escape.
But other limpets have a secret defence.
They deploy a slippery shield
which allows them to slide to safety.
And this limpet has its own personal bodyguard.
A scale worm with a nasty nip.
The starfish prefers food that doesn't bite back.
The limpet carries on,
its bodyguard tucked safe under its shell.
But there is one creature
that limpets have no defence against.
A clingfish.
It has teeth that can lever under the shell
and twist the limpet off like a bottle top.
The clingfish then swallows it
shell and all.
(GULPS)
Rock pool dramas like these last just a few short hours
before the tide returns.
Every day the sea becomes land and the land becomes sea.
Bringing new opportunities.
A Sally Lightfoot crab,
one of thousands of shore crabs just waiting for their moment.
Every day they gather on the tropical shores of Brazil,
waiting for the tide to go out.
Which exposes their feeding ground,
seaweed covered rocks, a hundred metres from the shore.
Getting there is a race against the tide.
They leap from rock to rock.
These crabs seem to be afraid of the water.
And for good reason.
The Moray eel.
The chain Moray is a specialist crab hunter.
It's blunt teeth can easily grip and crush a crab's shell.
It's the crab's deadliest enemy.
But the crab's feeding grounds are still a long way off.
They must press on.
Halfway.
But their enemy has other ideas.
Crossing the land
to reset the ambush.
To feed, the crabs must keep going.
But nowhere is safe.
An octopus. Also a crab killer.
The crabs make a dash for it.
Made it.
Risking life and limb
to graze on these seaweed pastures.
But in two hours' time when the tide starts to turn,
they will have to run the gauntlet all over again.
Tides are not the only force to have an impact on the coast.
(WAVES THUNDERING)
The greatest waves originate far out to sea
and roll in towards the coast, growing as they come.
As the shallowing sea floor drags at their underside,
their crests rise up to a hundred feet high,
topple over and break.
Many of the biggest surfed waves in the world
are formed off Nazare in Portugal.
Every day along this coast, the impact of the waves is equivalent
to one and a half million tonnes of TNT.
Wave power gradually moulds and reshapes our coasts.
In some parts of Europe,
waves wear away as much as three metres of coastline each year.
The rate at which the waves reshape the rock
depends on its hardness.
Where soft rock lies below hard,
dramatic arches are craved.
It's an endless assault
that gradually sculpts vaulted cathedrals of stone
as here in northern Spain.
(BIRDS CHIRPING)
And wave power creates towering fortresses
like these cliffs in these Arctic,
home to tens of thousands of breeding seabirds.
The faces of the cliffs are accessible only from the air
and have plenty of nooks and crannies for those that can get there.
But to feed, seabirds must still master the ocean world beyond.
(GULLS SQUAWING)
The puffin.
He's a fisherman...
(SQUAWKING)
...and a father.
He has a mate for life.
Both share the burden of raising their week-old chick,
their puffling who needs five square meals a day.
The parents alternate fishing trips.
(CHIRPING)
It's dad's turn.
(SQUAWKING)
When fish stocks are low,
puffins must fly as much as 30 miles off to sea
to reach the good fishing grounds.
Once there, they plunge into another world.
Good fishing spots are hard to come by, and they have company.
Guillemots.
Like the puffin, their wings are short and good for diving.
Puffins can hold their breath for over a minute
and dive as deep as 40 metres.
A catch.
But it's a long way home.
(BIRDS SQUAWKING AND CHIRPING)
(SQUAWKING)
After an exhausting round trip of almost 60 miles,
this puffin's nearly made it.
But there are pirates on this coast.
Arctic Skuas.
All around returning parents are being robbed.
The skuas' long rake back wings
make them faster and more manoeuvrable.
Puffins must choose their moment wisely.
A near miss.
A last desperate burst of speed,
and it's made it.
(BIRDS CHIRPING AND SQUAWKING)
Safely home after a three-hour round trip...
(SQUAWKING)
... where his patient partner is waiting.
(CHIRPING)
Today their puffling will eat.
But where fish numbers are in decline,
many puffins now find it hard to get enough food for their chicks.
In the changing seas of today,
it can be even harder to be a successful puffin parent.
Overcoming the challenges of two worlds is seldom easy.
One marine creature has virtually abandoned the sea altogether.
On a few remote pacific islands,
lives the most terrestrial fish on the planet.
At the top of this metre-high limestone cliff,
an eight-centimetre long blenny has chosen a nest hole.
Up here, he can graze on the abundant algae
without any competition from sea-going fish.
The females are feeding beneath him.
He's keen to attract their attention,
but they are busy moisturising.
Staying damp is essential as they breathe through their skin.
To make himself conspicuous, he turns black
and flashes his orange fin.
He catches her eye.
But these Pacific leaping blennies,
seem afraid of the waves.
They're poor swimmers
and will be easy prey in the sea.
Time to try again.
She's tempted.
But once again distracted by a wave.
The male just won't give up.
Finally, she's hooked.
He makes way...
so she can enter his cave.
And he encourages her to lay her eggs
with his seductive dance.
He then fertilizes them in the safety of his nest.
The blenny has given up the sea for a life on land.
Others have made an even more successful move
but in a different direction.
Penguins have abandoned flying
and instead spend most of their lives swimming.
Their sleek survival suits of tightly packed feathers
are perfect for these freezing waters.
Yet, they must still come ashore once a year.
South Georgia, an island wilderness close to Antarctica.
(PENGUINS SQUAWKING)
Each spring, its beaches become the busiest on Earth
as hundreds of thousands of king penguins return here.
(SQUAWKING)
They're heading for the colony.
(GRUNTING)
But in their way lies the biggest wall of blubber on the planet.
(ROARING)
Elephant seals.
It's the breeding season
and the four-tonne bulls are fighting for control of their harems.
(TRUMPETS)
Best to wait for them to calm down.
(ROARING)
He can't fly over this barrier,
so he will have to walk as unobtrusively as possible.
And hope that sleeping giants will continue to lie.
(SNORES)
Careful.
(SQUAWKS IN FRIGHT)
(SEALS SNORING)
This could be tricky.
(PENGUINS SQUAWKING)
(ROARING)
A rival bull mounts a challenge.
The penguins could be caught in the crossfire.
(ROARING CONTINUES)
Eight tonnes of blubber collide.
(SCREECHES)
The towering beach master is victorious.
In the confusion, this penguin slips through.
Ahead are 40,000 chicks.
Hungry and over-excited.
(ALL CHIRPING)
But not every penguin has a chick to feed.
That's not why they're here.
There is another reason.
There is a trial of endurance that every penguin must face,
and it starts with a persistent itch.
His survival suit has been worn thin
by months of swimming in the rough southern ocean.
His solution is drastic.
Shed all four layers of feathers as quickly as possible.
The process is known as a catastrophic moult.
Until their feathers regrow,
penguins will remain rooted to the spot.
(ALL SQUAWKING)
Having starved for a month,
they're now fully waterproofed and insulated once more.
Lean, hungry and eager to return to a life at sea.
(SQUAWKING)
Thanks to their waterproof plumage,
penguins are able to make the most of both worlds
even in some of the harshest conditions on Earth.
The coasts of South Georgia
are currently protected by their remoteness.
Other coastlines are much more vulnerable,
and they are now changing faster than ever before.
Two thirds of our major cities are on our coasts.
It's estimated that in the next decade,
we can expect 10% of the world's remaining wild shores
to be taken over by human development.
Yet every year, just off Florida 's Palm Beach
and extraordinary spectacle appears almost unnoticed.
The biggest gathering of coastal sharks on the planet.
Spinners and blacktips.
Ten thousand of them.
Every January, they seek out these warm shallows
as a stopover on their migration northwards.
Sharks have been gathering here since long before people arrived.
But today, they face levels of pollution
and habitat degradation as well as fishing pressures
that their ancestors would never have experienced.
It's not longer enough for coastal creatures
to master their own worlds.
Now they must face the many challenges that come from our world, too.
To film the most surprising coastal wildlife,
the Blue Planet II team
travelled to some of the remotest shores on the planet.
One destination was the Galapagos islands.
Here they were in search of an almost unbelievable story
brought to them by a local cameraman Richard Wollocombe.
RICHARD: Well, I was talking to a friend of mine
who's a fisherman over here,
and he said that one day he turned up here in this bay,
and suddenly he saw a group of sea lions chasing these massive tuna
up onto the beach.
And I was like, "Yeah, funny one. I don't believe a word of that."
That just sounds too unreal.
Still the lure of the fisherman's tale
was too great to ignore.
RICHARD: I'm a little nervous that if it doesn't happen,
there goes my credibility.
The Blue Planet II team launch a full-scale expedition,
but one of them is still skeptical.
It's gonna be pretty spectacular if...
if a sea lion could actually chase down and kill a tuna.
I'm still yet to be convinced.
They set up camp in this barren cove,
home for the next month.
The local wildlife, famed for its tameness,
is curious to meet its new neighbours.
(SHOOING)
With no sign of the sea lions,
the crew stake out the cove with remote underwater cameras.
Field assistant Roby Pepolas takes first watch.
ROBY: This is the point of view
where we try to see the sea lions come in
jumping over the water.
If they're definitely coming very close,
they say, "Action, action," or "Rock and roll."
(LAUGHS)
Three hours later...
(SPEAKING SPANISH)
The aerial team are first up.
It's a sea lion chasing tuna into the bay.
Oh, he's got it. He's got it.
Unbelievable!
Look at that, he's still struggling.
Holy moly!
He's lost him.
The tuna gives the sea lion the slip.
Over the coming days, more sea lions arrive in the cove
chasing in yellowfin tuna.
RACHEL: Yeah, yeah, yeah, ooh!
I bet you there's more tuna and another sea lion.
There's like six tuna in that bay.
One sea lion has caught Richard's attention,
and he's affectionately called him Tagboy.
RICHARD: He's really different. He's, like, a prolific hunter,
and he's really agile.
It's just fascinating to watch and see the picture emerge about who he is.
From above, the drone is revealing
how the group of sea lions are hunting together.
From the air, we really see the strategy of the sea lion
and see them with their individual roles as well.
Tagboy stays off in the middle of the channel
to make sure none of them escape.
Everyone's got a role
and they're really a team in bringing them together.
Although the sea lions have been hunting in the shallows,
the crew are yet to see them drive a tuna onto the beach.
And to make matters worse, the sea lions aren't alone in this cove.
Galapagos sharks, each two metres long.
The shark almost beached itself
and stole the tuna from the big sea lion,
who is now really angry.
Despite the sharks,
to reveal the full story, Richard needs to get in the water.
RICHARD: Classic shark attack scenario. Blood in the water, shallow,
and easy mistaken identity.
RACHEL: Watch your hands, Roby.
DAVID: The crew gain some protection from chain mail suits.
This is not a shark pool.
One, two, three, four, five, six sharks (CHUCKLES) now.
With so much blood in the water, the sharks go into a feeding frenzy.
RICHARD: Make mince meat of these tuna in seconds.
To be so close to something so unbelievably ferocious
and dangerous, quite frankly,
is amazing. It's... It's...
It's nice to be able to hide behind all this though.
But then, after a week of increasing activity,
the sea lions suddenly stop fishing.
ROBY: It's the first day though
that we haven't seen any action during the whole day.
Since we start.
We are kind of worried.
The tuna have disappeared.
Richard is worried.
The signs are starting to show across the globe
that the seas are warming, they're becoming less productive.
Galapagos marine life relies on cold, deep currents
welling up intermittently to fertilize the surface waters.
(BARKING)
If those upwellings become less consistent,
er, their lives could well be in jeopardy.
In the past,
when these cold water upwellings have temporarily stopped,
many sea lions have starved to death.
And a warming ocean could further weaken these upwellings.
Then after two weeks of nervous waiting,
a hopeful sign.
A thick fog descends over the cove.
We've got very cold water that's come up, upwelled,
and spread across the ocean,
and mixed with the warm air, creating the fog
and hoping that this cold water
will just kick things off a bit, you know, and get the action going.
As the fog clears, a welcome sight...
The tuna are back with sea lions hot on their heels.
The crew leap into action.
(SPEAKING SPANISH)
Being in the water,
Richard can at last follow the sea lions' teamwork
and finally film Tagboy beaching a tuna.
RICHARD: The know the bottlenecks in this labyrinth.
They know how to push them into those bottlenecks
and threre was just Tagboy,
almost his entire body was blocking the entrance,
and he was just gently back and forth tiring the fish out.
Absolutely extraordinary. Really, really impressive.
Director Rachel
has a newfound respect for the sea lions.
RACHEL: I had no idea they were capable
of this level of planning and strategy and teamwork.
I had no idea they were this intelligent.
Richard has succeeded in filming this unique hunting strategy
and in doing so has proved the fisherman's tale to be true.
RICHARD: The sea lions' intelligence is unbelievably sophisticated.
So to say that my expectations have been exceeded
is a sight understatement.
This is been one of the most remarkable times
I've ever had here in the Galapagos.
Next time...
We travel the world to uncover the biggest issues facing the ocean...
meet the passionate people
who've devoted their lives to protecting it
and discover what the future holds for our blue planet.
(THEME MUSIC PLAYING)