All language subtitles for Blue.Planet.II.S01E06.Coasts.2160p.UHD.HDR.BluRay.x265.DTS-SCOTLUHD.he_auto

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.

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.

He's failed.

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.

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.

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.

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.

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.

The puffin.

He's a fisherman...

...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.

It's dad's turn.

When fish stocks are low,

puffins must fly as much as 30 miles

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.

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.

Safely home
after a three-hour round trip...

...where his patient partner is waiting.

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.

Each spring, its beaches become
the busiest on Earth

as hundreds of thousands
of king penguins return here.

They're heading for the colony.

But in their way lies the biggest wall
of blubber on the planet.

Elephant seals.

It's the breeding season

and the four-tonne bulls are fighting
for control of their harems.

Best to wait for them to calm down.

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.

Careful.

This could be tricky.

A rival bull mounts a challenge.

The penguins could be caught
in the crossfire.

Eight tonnes of blubber collide.

The towering beach master is victorious.

In the confusion,
this penguin slips through.

Ahead are 40,000 chicks.

Hungry and over-excited.

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.

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.

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.

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.