All language subtitles for CD0CC3C68508ED3A9FCAB39BB7AAC3D7_eng

Here in Britain and Ireland, we have
some of the richest seas in Europe.

Our varied coastline, if you include
all the many offshore islands,

is over 22,000 miles long,

and none of us live more than
70 miles away from the sea.

Yet few of us have seen the
wonders beyond the beach

and beneath the waves.

In this episode,
we will take you

from the most
southerly point of the

United Kingdom to
the furthest north,

to explain why our seas
can be so productive

and reveal the threats
that they face today.

Every winter, a warm ocean
current, the gulf stream,

drives huge storms
across the Atlantic...

..away from the Caribbean and
straight towards our shores.

There, every winter, they batter
the west coasts of our islands.

Waves with energy built
up across an entire ocean

are hurled at our coasts.

Walls of water more
than ten metres tall

crash repeatedly onto the rocks.

And as the water at
depth is churned,

it brings nutrients up
towards the surface.

These nutrients, combined with
the warmth of the gulf stream,

are the reason why marine
life here proliferates

with such extraordinary
richness and variety.

Each year, in autumn,

evidence of this marine
abundance appears on land.

13,000 grey seals haul out
on Blakeney Point in Norfolk.

It's the largest seal
colony in England.

Females, having spent most of the
year feeding in our rich waters,

are preparing to
produce their young.

Newly born, the
pups are helpless...

..and for their first few weeks,
entirely dependent on their mothers.

Seal milk is more
than 50% fat...

..and the pups put
on two kilos a day.

At first, parent and
pup are inseparable.

But then, after a few days, the
youngsters start to explore.

Other females don't
tolerate the appearance

of unrelated pups
on their patch.

Posing an even greater
threat than the females...

..are the males.

Three metres long and
weighing 350 kilos...

..they have come here to mate.

They know that soon
after the pups are born,

the females will become
sexually receptive once again.

This big male tries to
control all the females

on this stretch of the beach.

But he has a rival.

ROARS

The big male warns
off the challenger,

but the intruder
takes no notice.

ROARS

There's only one
way to settle this.

Violence.

When the males fight,

they take no notice of any
pup that gets in their way.

GRUNTS

The pup's mother intervenes...

..allowing her pup
to wriggle away.

Finally, the battle turns.

The intruder starts to
retreat towards the sea.

Now, the smaller
males join the chase.

The big male has retained
his right to mate.

Despite these battles, Blakeney
Point still provides the pups

with an excellent start in life.

5,000 are born here each year.

A remarkable 40% of the world
population of grey seals

lives around the British Isles.

Impressive evidence of
the richness of our seas.

Beneath the surface, that
wealth is very evident.

Cold, nutrient-rich
currents from the north

mingle with the warm
waters of the gulf stream,

and support an astonishing
variety of plants and animals.

There are more than 10,000
different species here.

The effect of the gulf
stream is felt most keenly

at our southernmost point,
around the Isles of Scilly.

Here grows one of the
biggest stretches of seagrass

to be found anywhere in
British and Irish waters.

Seagrass is important globally
because it collects carbon

up to 35 times faster than
a tropical rainforest.

But we have lost nearly
90% of our seagrass,

mainly because of pollution
and disturbance of the seabed.

Nonetheless, these
marine meadows

are home to a wide
variety of small animals.

Including this perhaps
somewhat surprising one.

A spiny seahorse.

One of just two species of
seahorse that live in our waters.

They thrive in the warmth
brought by the gulf stream.

The seagrass provides them

with the seclusion they
prefer for their courtship.

A crucial part of
their underwater dance

involves a gentle
entwining of their tails.

It's behaviour you might
think to be more typical

of the warm, balmy waters
of the Mediterranean.

And there is another creature

that is also more usually
found in warmer waters.

The common cuttlefish.

It's the most northerly
of all cuttlefish species.

This pregnant female, about
the size of a rugby football,

is being guarded by a male as
she prepares to lay her eggs.

First, she cleans
her chosen site

by squirting jets of
water over the seaweed.

Several dozen black
eggs are already here,

having been laid
the previous day.

And now she adds more...

..one by one, until there
are up to 3,000 or so.

A month later...

..during the night, the
eggs start to hatch.

A perfectly formed baby
cuttlefish, no larger than a pea.

Within a few weeks,

a male has grown to a length
of around six centimetres

and is already a
stealthy hunter.

His eyesight is so sensitive that
he's able to hunt by moonlight.

But when the moon disappears...

..even he cannot see

and the darkness usually
brings hunting to an end.

But on just a few
nights each year...

..something
extraordinary happens.

Tiny light-producing algae create
vast clouds of bioluminescence.

They're stimulated to switch on by
any sudden movement in the water.

Even the slight swirl produced
by a tiny crab as it breathes

has an effect.

The hunter must
move very smoothly,

to avoid creating a
light show of his own.

The light of the algae has
enabled it to see its prey

and so hunt
throughout the night.

A year later, the
cuttlefish are fully grown

and this male is now
looking for a female.

But the traditional
breeding site is empty.

The cuttlefish that
gathered here to mate...

..have been caught
in a fishing pot.

They may be among the most
intelligent animals in the sea...

..but they've been
fooled by a simple trap.

And once in it,
there is no escape.

The male outside
spots a possible mate.

But he can't reach her.

Our cuttlefish population can
tolerate some loss to fishing,

but surely we shouldn't put pots
where they habitually breed,

and prevent them from
producing their next generation

Away from the coast, the seabed
may seem barren and lifeless.

But looks can be deceptive.

This muddy seafloor is
rich in bacteria and algae

and provides food for
one animal in particular.

A slow-moving creature that can grow
up to a length of six centimetres.

The royal flush sea slug.

Thousands graze
the seafloor here.

But with so much competition
for the same food,

supplies eventually run out.

And the sea slugs
have to move on...

..in their own strange way.

They flap their wing-like mantles
and rise up from the seabed.

Drifting on the slow current,
they can travel for miles.

This extraordinary mass migration
has never been filmed before.

Eventually, they reach
new feeding grounds.

And now they can start
hoovering the seabed once more.

As spring turns to summer,

another very different migration
begins all along the south coast,

and for a very different reason.

A young female spider crab.

She is searching these sandy
plains for others of her own kind.

Spider crabs are
normally solitary,

but now, in the summer, they
start to assemble into groups.

And then, when there are enough
of them, they start to travel.

Together, they journey for
miles across the seabed,

all heading in the
same direction.

Groups join together

and the travellers become one great
horde, several-thousand strong.

They are about to face the most
dangerous time of their lives.

They have outgrown their hard shells
and must now escape from them.

A new shell is expandable,

but it remains soft
for several hours

and until it hardens,
its owner has no defence.

That is why they've made
this journey together.

There is safety in numbers.

Ocean currents are one reason
why our waters are so rich.

Another is the exceptional
size of our tides.

Vast amounts of water

are continuously transported
around our islands

by these powerful currents.

The third biggest tidal
rise and fall on the planet

occurs in the estuary
of the River Severn.

From low tide,

the sea level rises by as much as
the height of a five-storey building

and then falls again,
twice every day.

These huge transformations
churn-up the nutrients

and replenish the mudflats.

Further north, on the
west coast of Scotland,

the power of our tides creates
another great spectacle.

The Corryvreckan whirlpool.

25 metres across.

It's the third largest
whirlpool in the world.

These powerful tidal
currents mix-up the water,

constantly bringing nutrients from
the depths up to the surface layers.

And the influence of the tides can
extend right down to the seafloor.

The animals down here thrive
in these ever-moving currents.

Every square inch is
bursting with life.

The flowing water brings a
never-ending supply of food.

Brittle stars and sea cucumbers
compete to collect all they can.

So many creatures inevitably
attracts predators.

The seven-armed starfish
- half a metre across.

The brittle stars do their
best to get out of their way.

The huge starfish
feel for their prey

using hundreds of
sensitive tubed feet

that line the underside
of their arms.

Yet, not every animal they
encounter tries to escape.

This hermit crab, with
its powerful claws,

is well able to defend itself.

Finally, the persistent starfish
find what they're looking for.

A queen scallop.

Its lines of simple black eyes are
able to detect fast-moving threats.

But the starfish
moves quite slowly...

..and the scallop
doesn't notice.

Only when the scallop feels
the predator's probing feet,

does it react.

It swims away by clapping together
the two parts of its shell.

It's a surprisingly
effective technique,

and with luck will carry
the scallop to safety.

But scallops don't have a
strong sense of direction...

..and the starfish
just keep coming.

The starfish first pulls
the scallop shell apart

and then inserts its
extendable stomach

to digest the scallop's flesh.

The smell of the feast
drifts through the water

and attracts scavengers.

Whelks.

They are the clean-up crew.

Tidal beds like these can easily
be destroyed by bottom-trawling.

Protecting those that
survive is essential

if we are to preserve
the richness of our seas.

100 miles from mainland
Scotland lies Shetland,

the most northerly part
of the British Isles.

Because this archipelago
is in the open ocean,

it has some of our
cleanest waters.

This is one of the
reasons why Shetland

is our main
stronghold for otters.

More than 1,000 live along its 1,600
miles of undisturbed coastline.

Shetland's isolation and its
relative lack of pollution

suits these animals very well.

Elsewhere, most live
in or beside rivers,

but here they spend much
of their time in the sea.

Each has its own territory

and knows where its prey
is likely to be hiding.

But the waters in which they spend
so much of their time are chilly,

and otters need a lot of
food to keep themselves warm.

They can hold their breath
for up to 90 seconds..

..and reach hunting grounds
as deep as ten metres.

In summer, the waters teem with
small fish, such as eelpout,

which are easy to catch and are
excellent food for the cubs.

Little wonder that Shetland has
the greatest density of otters

anywhere in Europe.

Otters are not the only stars
in Shetland's natural history.

Around its coast are habitats
of global importance.

Forests of kelp.

They are among the thickest
and most vigorous of their kind

in Britain and Ireland,

with individuals growing
to over two metres tall.

Like the seagrass,
this underwater forest

captures great
quantities of carbon...

..and provides a home for
a wide range of animals.

One type of kelp
here, the furbellow,

has an especially
feisty resident.

Its hollow base is the
favourite home of clingfish.

This minute
two-centimetre-long male

has been left by his female
to look after the eggs.

Hundreds of them are glued to the
interior of a furbellow's stem...

..and they're almost
ready to hatch.

It's quite a
responsibility for him.

All day long, he fans
fresh, oxygen-rich sea water

across the eggs.

He inspects them regularly

and quickly removes any
that are infertile or dead.

But his nursery is under attack.

Sea urchins are
devouring the furbellow.

Their powerful jaws are
destroying the clingfish's home.

His babies are under threat, still
stuck to the walls of their nursery.

There is no escape.

Their tiny father takes action.

He tries to drive the urchins
away by beating his tail.

But it makes little difference.

Time for another strategy.

The urchins are covered
in sharp spines...

..so the brave little father nips
the urchins' sensitive tubed feet.

Finally, the urchins give up and
go in search of easier meals.

The little male clingfish
has saved his young.

He is part of a
crucial community

that maintains the balance
in this marine rainforest.

At the height of summer, the
power of the sun combines

with the stirring action of
the tides and the waves...

..and the ocean blooms.

The creators of these blooms

are myriads of floating,
microscopic algae.

They are the basis of the entire
food chain in the open ocean.

And when conditions are right, they
multiply at an astonishing rate.

Their repeated blooms are
one of the main reasons

why the seas around Britain
and Ireland are so productive.

The floating plants support a great
community of tiny floating animals,

the zooplankton.

Tiny creatures that drift in great
clouds driven by the ocean currents.

Among them are copepods,
tiny crustaceans

that feed on the microscopic
algae floating alongside them.

The rest are mainly predators.

Many of these are also tiny.

The larvae of bottom-living
animals like lobsters and crabs,

some only 5mm long.

There are also sea gooseberries,

which propel themselves
through the water

with rows of pulsating bristles.

They may look fragile, but they
are surprisingly effective hunters.

They extend long,
thread-like tentacles.

Other drifters that get entangled
are reeled-in and eaten.

The sea gooseberries
themselves, of course,

are also prey for
larger predators...

..such as the melon comb jelly.

It has a particularly
large mouth.

When it opens it, the
suction it creates

pulls its prey straight
into its stomach.

Despite the richness
of our seas,

climate change is seriously
reducing the amount of zooplankton.

And this has an effect on
the entire marine food chain,

right up to real giants.

The largest fish in our waters is
as long as a double-decker bus.

The basking shark.

It uses special sieve-like
structures on its gills

to filter out the zooplankton.

And they feed on nothing else.

In summer, these giants come close
to the coast all around our isles.

They're normally solitary,

but when the plankton reaches
the peak of its abundance,

the sharks come together.

They swim in formation.

Plankton that escapes one mouth
will be scooped-up by the next.

In just a few special places

along the western coasts
of Britain and Ireland,

basking sharks gather in large
numbers to feed and breed.

Thousands find their
way here each year...

..a major part of the
global population.

Plankton feeders
come in all sizes.

Sand eels are only
30 centimetres long,

but they occur in vast shoals.

Like so many species,
overfishing and warming seas

have drastically
reduced their numbers.

They are essential prey for a
wide range of top predators.

Dolphins scour vast areas of the
open ocean to track down the shoals.

And following the dolphins
comes an ocean legend...

..bluefin tuna.

Weighing up to 700 kilos

and with a top speed
of more than 40mph,

these powerful predators can
make quick work of the shoal.

Bluefins have been absent from
our waters for more than 50 years.

And they have only
recently returned.

If they are to stay,

the overfishing of our seas
will have to be stopped.

In the sky above...

..gannets, looking for fish
such as mackerel and herring.

They hit the water
at over 60mph.

The impact is enormous.

To avoid breaking their
wings, they fold them back

and turn themselves
into streamlined arrows.

65% of the world's population
of northern gannets

find their food in our seas.

But perhaps the bird that depends
most on the still-rich waters

around Britain and Ireland
is the Manx shearwater.

Every year, our
coasts are visited

by almost the entire global
population of this sea bird.

Here in Cardigan Bay
off central Wales,

they gather in their thousands,

attracted by the
richness of our seas.

Each summer, 350,000
pairs all return

to this tiny island of Skomer
off the Pembrokeshire coast.

This is the largest
breeding colony in the world

and most of the island is
honeycombed with their burrows.

Tonight, under the
cover of darkness,

their chicks are starting
to leave these burrows

for the very first time.

Watching them do so is an
unforgettable privilege.

This young bird has just
emerged from its nest hole,

maybe for the first time.

It's about to make the most
important journey of its life.

And it needs to get every inch
of altitude before it takes off.

I can just see beyond me...

..there are more of them.

One, two, three, four.

It's just exercising
its wings...

..in preparation for this
extraordinary flight...

..which will take it 6,000
miles across the oceans

to South America, to
Brazil and Argentina.

And then, after some four years,

once again it will set out
on a long oceanic journey,

a further 6,000 miles back to
this one small island of Skomer.

Are you going to go?

It's hesitating and
who can blame it?

An enormous journey awaits it
once it takes off from here.

This is the headquarters
of this astonishing species

..and we are its custodians.

Come along.

Come along. Come along.

Are you about to take off?

Good luck!

HE CHUCKLES

What an astonishment.

A lot has changed in my lifetime

and today the
wildlife we still have

faces greater threats
than ever before.

Our sea birds remind us that
here in Britain and Ireland

we are very fortunate to have some
of nature's greatest spectacles

right on our doorstep.

Because this is our home,

it can only be our responsibility
to restore and protect our wildlife.

Perhaps you can be the first
to pass these wild isles

on to the next generation in better
shape than you inherited them.

From the Isles of Scilly in the
south, to Shetland in the north,

the ocean team spent 300 days
filming the marine wildlife

of the British Isles
as never before.

They captured new behaviours,

experienced the worst
of the Atlantic weather,

and witnessed intimate moments in
the lives of our ocean wildlife.

Doug Anderson, is one of the world's
leading underwater camera operators.

He's worked all over the planet,

filming some of the ocean's greatest
spectacles and largest inhabitants.

And for this series, he filmed
the majority of the ocean episode.

His passion for the underwater
world began on the Isle of Arran,

off the west coast of Scotland.

My first underwater
experience was in Lamlash Bay

in front of my
grandparents' house

and it is burnt into my memory.

My dad had made me a wet suit and I
remember putting my face underwater

and just being blown away
but the wildness of it.

You know, there were
crabs and little fish

and it felt like a wild place.

I remember lifting my head up

and looking over my shoulder
back at the village -

there was, like, the
policeman doing his round,

and people going to the
shop and I was like,

"Oh, the ocean is a wild place
and behind me is what people do."

And I never recovered.

After learning to dive,

Doug's passion for
the underwater world

took him on a journey
far from home.

I eventually got a job on a
series called The Blue Planet,

back in the mid-'90s.

And then just found myself
on plane out to the Azores.

Yeah, I was, like, 27 years
old, and that was the start.

Until now, he's never
had the chance to show

what the British
Isles has to offer.

On the Wild Isles project, it just
felt like an amazing opportunity

and responsibility to take
everything I've learned

in 25 years of working
all over the planet,

and just applying
all of that to here.

Although they might
be easier to reach,

our waters have
their own challenges.

This project, in many ways,

has been the hardest professional
experience of my life.

Everything that you do on the ocean
in the North Atlantic is tough.

We can have four
seasons in a day.

This unpredictability
makes filming in our seas

a matter of boom or bust.

The team must be
on constant standby

to mobilise quickly when
conditions are right.

In Shetland, they're
heading for the seabed.

To record life down here,

Doug has designed and built his
own bespoke underwater tripod.

High-powered lights
illuminate the seafloor...

..and weights stabilise the rig,

allowing Doug to film a time-lapse
of these slow-moving creatures,

revealing a world that few people
will ever see in actuality.

Below the kelp, Doug takes
his design a step further -

a motion-controlled slider
for tracking timelapses.

Now, he can move the camera
with pinpoint accuracy,

revealing how urchins travel
through this marine forest.

A shot that's taken
months of preparation.

But not everything in our
oceans is as slow-moving.

Off the coast of Cornwall,

the team are chasing one of the
ocean's fastest inhabitants,

bluefin tuna.

They have only retuned to our
waters in the last few years.

We've got all the ingredients
that we need here.

We've got dolphins,
we've got tuna,

there's gannets here,
and shearwaters.

But we need it to come together
into something that we can film,

and that's a bait ball.

So it has to be a patch of fish
jammed up against the surface

in reasonable visibility
to make it work, so...

..fingers crossed.

Bait balls don't last long.

They can be over in
a matter of minutes.

So to film tuna hunting,
speed is everything.

Radio call from one of our
contacts, so we screamed down there,

only to discover we were
just a few moments too late.

Which is really frustrating.
We've got a really fast boat.

This is so new, this set-up here,
these bait fish coming here.

It's five years,
so we're just...

Everyone's just working it out
and it seems like we're not alone

cos it's like the dolphin and the
tuna are just beginning to find it

and exploit the
resource as well.

The team use a drone
to help locate the tuna

before the bait balls disappear.

The exciting thing
is, this is England.

We've got literally
Falmouth right there

and we've got these crazy pods of
common dolphins rolling through

and there's bluefin
showing every now and then.

It's an amazing
kind of ocean scene.

Although it looks
good from the air,

poor visibility underwater prevents
Doug from getting a clear shot.

Yeah, a total glimpse, just
like the briefest of moment.

Pretty green water,
I just get in,

and they just come through
and just roll through.

In the hope of finding clearer
water, the team change location.

We're further down the coast.

We're going to be
working further offshore,

and we're going to be trying to join
the blue water with the bluefin.

If a big patch of pilchards on the
surface or mackerel comes together,

then come away with
what we want from this.

We have tuna, they're all
over the place just now.

We just need to wait for this
sort of pot to boil, you know.

For the bait to come
together into a lump

for long enough, for it to go static
so that we can get in and film it.

The plan works!

The team finally get the conditions
they have been seeking for so long.

To actually see a bluefin
tuna underwater in England

is just unbelievable.

The return of bluefin
tuna to our waters

is a sign that their
population is recovering.

But it's still a fraction of
what their numbers could be.

Since Doug left Arran
over two decades ago,

the coastal community,
including his family,

created Scotland's first
marine No Take Zone.

Since its creation in Lamlash Bay,
biodiversity has increased fourfold.

But it's one of just a handful of
No Take Zones around our wild isles,

that combined, cover
less than 1% of our sea.

The abundance of
life within them

spills out into the
surrounding waters,

enriching and strengthening
the wider marine environment

The way to get British seas
back is to allow large areas

to return to a natural state,

and maintain those very highly
protected areas for a long time.

For Doug, celebrating the
beauty of British waters

has been a chance for him
to give something back.

If I can play a tiny part
about providing the visuals

to allow that conversation to
happen in a meaningful way,

for people on all
sides of the argument

to imagine what lies
beneath those grey waves,

then I think it would be
an extraordinary thing.