All language subtitles for D6623AD4D541D92064B316C96837B4CA_eng

The world's greatest
wilderness, the open ocean.

It covers over half the
surface of our planet.

Here, there is nowhere
to hide and little to eat.

It's the marine equivalent of a desert.

And patrolling this
desert, spinner dolphins.

They stick together.

In a super pod, 5,000 strong.

That maximizes their chances
of finding something to eat.

Like all who live here, they
must go to extraordinary

lengths to make their
home in the Big Blue.

There are rare moments when
these empty seas can explode with life.

Lanternfish off the Pacific
coast of Costa Rica. They're

scarcely bigger than minnows,
but what they lack in size,

they make up for in numbers.

They are one of the most
numerous fish anywhere.

Normally, they only come to
the surface at night to feed on

plankton. But this immense
shoal has risen during the day,

almost certainly in order to spawn.

For the dolphins, this would be a balancer.

They have located the shoal
using their echo sounding calls.

But they have to get to it quickly.

They are not the
only hunters here.

Yellowfin tuna have
also detected the shoal.

And behind them, with their
two-meter wingspans, mobula rays.

Now, sailfish, one of the fastest
fish in the sea, have joined the chase.

The lanternfish may return
to the deep at any moment.

But now, the dolphins have got here.

They swim beneath the
shoal, pinning it to the surface

and forcing the lanternfish
to pack more closely together.

And now, the sea begins to boil.

The tuna charge into the
shoal at over 40 miles an hour.

The slower swimming rays arrive at last.

With their immense mouths agape, they
scoop up the lanternfish by the hundred.

The shoal has now been
largely dispersed, and the sailfish

pick off the survivors. In
just 15 minutes, all that's left

is a silvery confetti of scales.

But here, such feasts
are only too infrequent.

Whilst the dolphins perform
great feats of endurance, others

are driven to even greater
extremes to find food in this

ocean desert.

A sleeping giant.

A sperm whale.

This family is resting
between bouts of feeding.

Who knows what the owners of the
biggest brain in the planet dream about?

One has a calf. It's
about two weeks old, but

still dependent on its
mother's milk. It's hungry.

It communicates with its
mother using a pattern of clicks.

But its mother slumbers on.

The calf, covered in suckerfish, of which
it can't yet rid itself, has to be patient.

Sleep over and refreshed.
The whales move on.

Sperm whales don't wait
for their prey to rise to the

surface. They swim down
into the depths to find it.

They take a series of heavy breaths to

saturate their blood with
oxygen. Then, down they go.

This entire family dives
together in search of squid.

A mother will push her body
to the limits of her endurance,

and already it's hard for
her calf to keep up with her.

The calf sticks to its mother as
closely as it can, touching her frequently,

as if for reassurance.

About 300 meters down, it seems
the calf can't hold its breath any longer.

In their early years, calves
are forced to sit out the hunt.

The adults continue their dive.

The mother changes her calls into a
series of louder and more rapid clicks.

She's now using sonar to
hunt down shoals of squid.

At 800 meters, a burst of clicks.

Then silence.

She's made a catch.

The hunters could be
away for as much as an hour.

Finally, the mother returns from
the deep with a stomach full of squid.

After a long wait, this hungry
calf can take some milk.

It's one of the richest
produced by any mammal,

and the calf guzzles
a bathful of it a day.

It may be six years
before a calf masters the art

of deep diving and is
able to find food for itself.

The emptiness of the Big Blue is
what makes life so hard for hunters.

But it's this emptiness that makes
it comparatively safe for prey.

A baby turtle, hatched
just days ago, is leaving the

crowded, dangerous waters
of the coast and heading for the

open ocean.

Only recently have we
begun to solve the mystery of

where baby turtles disappear
to in their early years.

To start with, they fill
their little stomachs with

plankton, but soon they need
something more substantial.

Hundreds of miles offshore, in every ocean,
there are communities of young castaways.

So, anything that floats attracts them.

A log. It may have been at
sea for several years, and it

has already become the center
of a small community. Young

pufferfish are here for the same reason.

A floating log is just the
kind of refuge this young turtle

has been looking for. Here,
there's not only seaweed on

which to graze, but barnacles.

But it's important to stay undercover.

A young, ocean-going,
silky shark is here too.

It's learning what tastes good, and

what doesn't.

We now know that
many young turtles stay in

such places for several
years, until adulthood.

Even if it means facing the
full force of the high seas.

The sun, beating down
on the deep blue, warms

the surface waters
so that they evaporate.

As the vapor rises, it condenses
into clouds. They rapidly

build into gigantic, burgeoning
towers, which eventually

generate violent storms some a
thousand miles across. High -enforced

winds sweep across the open ocean, building
waves that can rise to 30 meters tall.

Out here, ships have been
known to sink without trace.

130 million containers are
shipped across the oceans every

year, and on average, four
of them fall into the sea every

day.

In 1992, a few were lost that
contained a consignment of bath toys,

including 7,000 plastic ducks like these.

They started their travels a
thousand miles off Alaska.

Some drifted right across the
Pacific Ocean and reached Australia.

Others were carried north
and landed on shores between

Russia and Alaska. They even
found their way into the high

Arctic.

One duck, having been at sea
for 15 years and crossing three

oceans, eventually landed
on the west coast of Scotland.

Their travels vividly illustrate
how a network of currents

connects all our oceans
into one gigantic circulatory

system.

Many of the inhabitants
of the Big Blue rely on

these currents to carry
them to feeding grounds.

The Blue Shark.

It travels over 5,000
miles a year, riding on the

currents supported by
its broad wing-shaped fins.

This one may not have eaten for two months.

But the currents can carry
promising traces of fatty oils

from many miles away and
will lead it to its next meal.

After days of travel, the
smell of food gets stronger.

A dead whale recently struck by a ship.

This could be a real feast, but
the Blue Shark must be cautious.

Great White Sharks,

ten times heavier than a Blue, are
highly possessive around a whale

carcass. Great Whites

are eager to feed on
energy-rich whale blubber,

which we now know forms
a major part of their diet.

Once the Great White has
had its fill, smaller sharks,

like the Blue Shark, tackle
what's left of a carcass.

As the oils from this
dead whale spread more

widely, more and more
Blue Sharks appear.

Within days, the carcass
will be stripped of its blubber.

Then, no longer kept buoyant by its
oil, it will sink into the depths below.

The Blue, with its reserves
of fat replenished, can

now survive for another
two months without eating.

Over half of all animals in
the open ocean drift in currents.

Jellyfish cross entire
oceans, feeding on

whatever happens to
tangle with their tentacles.

Some can go to a meter, even
two meters across. And when,

by lucky chance, they
encounter a patch of sea rich in

plankton, their numbers

It's such a successful
strategy that jellies

are one of the most
common life forms on the

But among the jellies,
and looking somewhat like

them, is a rather more
complex and sinister creature.

The Portuguese Man O' War.

It floats with the help of a
gas-filled bladder, topped by a

vertical membrane. With that
serving as a sail, it maintains

a steady course through the waves.

Long threads trail behind it,
some as much as 30 meters long.

Each is armed with many
thousands of stinging cells. A

single tentacle could kill
a fish, or, in rare cases, a

human.

But among its lethal tentacles lurks a Man
O' War fish that feeds by nibbling them.

Whilst this fish has some resistance to the
stings, it must still be extremely careful.

Most other fish are not so lucky.

A tentacle has caught
this one and reels it in.

It's already paralysed.

Specialized muscular
tentacles transfer the victim to

others that digest the catch,
liquefying it with powerful

chemicals.

Eventually, all that is left is

a scaly husk.

This voracious Man O' War may
collect over a hundred small fish in a day.

For the most part, the Big
Blue seems featureless,

a place where the winds
blow uninterrupted by land.

But beneath the surface,
there are long mountain ranges,

deep trenches, and isolated
volcanic peaks that make it far

more varied than the human eye can see.

We're only just discovering,
in any detail, how

the inhabitants of the
Big Blue exploit that.

A lonely whale shark on a special journey.

She is as long as a small aircraft
and she weighs over 20 tons.

Like many sharks, she does not
lay eggs, but gives birth to live young.

She carries up to 300 of
them in her swollen belly.

She may be the biggest
fish in the sea, but the place

where whale sharks give
birth has not yet been found.

Today, however, we may
be a step closer to solving this

mystery. We have known that
great numbers of whale sharks at

certain times of the year
appear around the Galapagos

Islands. Here they assemble
around a tiny island that rises

abruptly from particularly deep water.

It's known as Darwin Island.

Here, swirling currents
bring up nutrients from the

deep, so enriching these
waters that they attract great

concentrations of fish from far and wide.

Thousands of hammerhead sharks also
assemble here. They are nearly all female.

They too, it seems,
have come here to breed.

The whale shark receives
an extraordinary welcome.

Silky sharks, themselves three meters
long, bounce against the rough skin.

Perhaps to scrape off any
parasites they might have.

These sharks could be a
danger to any newly born young.

So perhaps to avoid
them, the whale shark dives.

Down to around 600 meters.

And there she may release
her young. In these great depths,

away from the predators that
hunt in the waters above, and

with abundant food, her babies
could grow and eventually disperse.

No one, it is true, has ever seen
young ones in these little visited depths.

But the fact that hundreds of
expectant whale sharks come

here every year is strong
evidence that somewhere here lies

the nursery of the biggest fish in the sea.

There are almost 30,000 sizable islands,
scattered across the world's oceans.

One of them is South Georgia.

An ideal place for those ocean dwellers who
are compelled to land in order to breed.

The wandering albatross.

It may spend as much as
a year continuously at sea.

Searching for food, gliding
on wings that are three and

a half meters across, the
biggest of any living bird.

The entire world population
of 16,000 wanderers nest on

South Georgia and half a
dozen or so of the other smaller

islands that lie in the Southern Ocean.

It's spring, and this bird is returning
to the nest site it's always used.

Its lifelong partner is already here.

In South Georgia, individual
birds have been studied for

their entire lives, revealing
that older pairs in their late

30s will go to
extraordinary lengths to give

their young the best
possible start in life.

This chick is now several weeks
old, but still has its warm downy coat.

The chick will need a regular
supply of regurgitated fish and squid.

With food so scarce in the open
ocean, both parents may have

to scour thousands of square
miles just to provide enough

for one meal.

Aging parents struggle
on all through the Antarctic

winter to raise a chick that
is big, strong and healthy.

After some 130 days, the youngster begins
to replace its down with flight feathers.

Finally, nine months after their egg
was laid, this chick is ready to leave.

Of all the chicks they've
reared in recent years, such a

favored chick will have the
best chance of survival, but it

will also be their last.

Elderly parents never
recover from their exertions.

Surviving in the open ocean
has always tested animals to

the limit. But today they
face a new additional threat.

Plastic.

Just over 100 years ago,
we invented a wonderful new

material that could be molded
into all kinds of shapes, and

we took great trouble
to ensure that it was

hard-wearing, rot-proof
and virtually indestructible.

Now, every year, we dump
around 8 million tons of it into

the sea. Here, it entangles
and drowns vast numbers of

marine creatures.

But it has even more widespread
and far-reaching consequences.

A pod of short-finned pilot whales.

They live together in
what are perhaps the most

closely knit of families
in the whole ocean.

Today, in the Atlantic
waters of Europe, as

elsewhere, they have to
share the ocean with plastic.

A mother is holding her newborn young.

She is reluctant to let it go and has
been carrying it around for many days.

As plastic breaks down, it
combines with other pollutants

that are consumed by vast
numbers of marine creatures.

In top predators like these, the toxic
chemicals can build up to lethal levels.

It's possible her calf may have been
poisoned by her own contaminated milk.

Pilot whales have big brains. They
can certainly experience emotions.

Judging from the behavior
of the adults, the loss

of the infant has
affected the entire family.

Unless the flow of plastics
into the world's oceans is

reduced, marine life will be
poisoned by them for many

centuries to come.

The creatures that live in
the Big Blue are perhaps

more remote than any
animals on the planet, but

not remote enough, it
seems, to escape the

effects of what we
are doing to their world.

The biggest challenge
of filming in the vastness

of the open ocean
is to find your subject.

And the Blue Planet team
wanted to film one of the most

elusive of them all, the
rarely witnessed boiling sea.

Until now, this feeding frenzy
has been the stuff of legends.

After some promising
sightings off the northeast

coast of Australia, the team
heads out to investigate.

We know it's a phenomenon,
we know it's out there, the

scientists have documented
it, the fishermen have told us

about it, so we know it's
happening, but no one has been

crazy enough to attempt to
go out there and actually film it

except for us. The team start their search
a hundred miles out in the Pacific Ocean.

The reason it's called the
boiling sea is that the tuna are

actually coming out of the
water and attacking Atlantic fish

and it creates a lot of white water.

To film the boiling seas, the
team must first find a large

shoal of bait fish, most likely
to be lantern fish rising to

the surface at night to spawn.
A few days out, Adrian thinks

he may have spotted a giant
shoal on the echo sounder. What

we're seeing is a very,
very dense layer at about 200

metres water depth and so
the fact that we've got this would

suggest that we have a very
deep and dense layer of fish.

One of the best ways to film
at such depths in the open

ocean is to use an ROV, a remotely operated
vehicle, carrying a light-sensitive camera.

But working with such heavy equipment
in the high seas is a risky operation.

Fortunately, a team of
technicians is on hand

and 24 hours later
they're ready to relaunch.

Adrian drops them on top of
what he hopes is a large shoal

of lantern fish. Good news is
we've just put the ROV down,

we're down at 250 metres,
which means we've gone to almost

the end of the cable and
nothing's blown up, so we're back

in business. But there's almost nothing
there, just a thick layer of plankton.

Over the next three weeks they
don't find a single lantern fish.

This trip is the perfect illustration
of why we know so much

about the ocean. We came
out looking for something, we've

searched and searched and
searched and we still haven't

found it, even with every
single tool you could wish for. As

it turned out, the team
had been filming at the very

start of El Niño, an unpredictable
climatic event when sea

temperatures can suddenly rise and
disrupt the spawning behaviour of fish.

It would be 18 months
before conditions would

improve and the team
could continue their quest.

The other side of the
Pacific Ocean, off Costa Rica.

This time, rather
than searching for their

prey, the team are
looking for their predators.

But in the endless blue, even finding
a massive pod of dolphins isn't easy.

20 miles offshore, series
producer Mark Brownlow leads an

aerial filming team, scanning
thousands of square miles of

ocean.

But there's not a dolphin in sight.

Day three, no spinner dolphins.

Finally,

after 10 days on the open
ocean, they get their reward.

With dolphins in sight, the dive team
race to intercept them. The plan is

to film the dolphins feeding
frenzy from underwater.

They catch up with the dolphins.

But they're too late.

To stand the

chance of filming the dolphins feeding,
the dive team need to be more proactive.

Rachel hitches a ride,
following them underwater,

searching for any clue to
where they might go next.

Finally, after three weeks of
searching, the dive team catch

a huge feeding event. A
massive shoal of lanternfish being

rounded up by hundreds of spinner dolphins.

For the first time, the aerial team can
record the epic scale of this spectacle.

The vastness of

the ocean wilderness made capturing
this extraordinary event a great challenge.

But this is the reward, a
moment of unparalleled

drama in the immense
expanse of the Big Blue.

Next time, we journey into
the bountiful Green Sea.

These are enchanted worlds
home to strange creatures, where

only the most ingenious will live.

Thanks for watching.

See you next time.