Our Blue Planet Blue Planet II

In the course of making Blue Planet II,

we've explored every corner of the underwater world.

We've encountered extraordinary animals...

..and discovered new insights into how life is lived beneath the waves.

For years, we thought that the oceans were so vast

and the inhabitants so infinitely numerous

that nothing we could do could have an effect upon them.

But now we know that was wrong.

The oceans are under threat now as never before in human history.

In this final episode, we will meet the pioneers

who are striving to turn things around.

People who are helping to save

the oceans' most vulnerable inhabitants...

..and dedicating their lives to protecting the seas.

But is time running out?

Many people believe that our oceans have reached a crisis point.

So just how fragile is our blue planet?

Winter in the Arctic Circle.

Every year, the waters of Norway are the setting for one

of the greatest wildlife spectacles in the ocean.

Over a billion herring pour into these fjords.

The Blue Planet II team spent three years

documenting this astonishing event.

Such a wealth of prey attracts predators in extraordinary numbers.

Orcas...

..and humpback whales.

But this migration hasn't always been so bountiful.

Leif Nottestad is a Norwegian fisheries scientist.

It's been one of the most important fisheries that we had for centuries

along the whole coast of Norway, but in the late 1960s the herring stock

we see around us here was on the brink of collapse.

50 years ago, fishing was so intensive

that the herring had all but disappeared.

Orcas were seen as rivals,

and hundreds of them were killed.

It was only after the Norwegian government

imposed severe restrictions that the herring began to recover.

Today, this is once again an immensely productive fishery,

closely monitored by teams of scientists.

Marine biologist Eve Jourdain is one of the resident orca experts.

From 1982, orcas got protected in Norway and we have clearly

one of the largest orca populations in the world out here.

There are now over 1,000 orcas here, but with so many mouths to feed,

including ours, can the mistakes of the past be avoided?

To answer this vital question,

Eve and her team are using multi-sensor camera tags.

With the tags, we try to see how the orcas interact with their prey,

how they hunt, and all about the underwater behaviour

that we are not able to see from the boat.

A tag has to be attached to the orca in exactly the right position.

Here it comes, here it comes...

Ah, that's a good shot!

It is the least invasive method, it is suction cups,

so there is not a scratch on the whale afterwards,

which is something we really like.

While studying the orcas,

Eve noticed a worrying change in their behaviour.

They had worked out the easiest way to get a meal.

We have seen that the orcas are waiting

for those fishing boats to drop the nets.

ORCAS CALL

It acts like a dinner bell, and then all the orcas of the area gather.

Quite a lot of herring slip from the net,

and this is exactly what the orcas are looking for.

But this new tactic is dangerous, as Eve has witnessed.

We were there to monitor the behaviour of the orcas

scavenging around the net, and we realised that one large adult male

was actually trapped inside the net.

When the fisherman started to retrieve the net,

the orca was obviously starting to panic

and trying to pull as much as he could.

This orca was really fighting for his life.

Stringent rules require fisherman to get permission

before they open their nets...

..but that took time.

It was such a long process.

We thought that the whale was going to die of exhaustion.

Thankfully, the fishermen finally got the clearance

to release their net, freeing the exhausted orca.

It was a huge relief to see that this orca made it until the end

and finally got back to his family.

With marine mammals and humans competing so directly,

accidents are inevitable.

Two days after tagging an orca, it's released and Eve collects it.

This tag is full of secrets, you know,

because it has been on the whale for several days

and will just reveal exactly what the whales have been doing.

Pictures from the tag reveal their hunting technique in detail.

They dive below the ball of fish...

..and then backflip.

The powerful tail slap stuns the herring.

Eve can even work out how many fish the orcas are taking.

They can kill up to 30 herring with just one tail slap.

And then what is pretty amazing

is all the individuals of the group share the dead herring.

And it's not just the orcas feeding here.

Humpback whales are also drawn to the feast.

They, too, are being tagged and monitored,

giving fisheries scientist Leif a complete picture

of how much herring is being eaten.

The whales, they take probably less than 1%.

The fishermen take less than 10%.

So the balance there is that there is enough for everybody,

given that we manage this stock

in a sustainable and a long-term sustainable way.

But it's estimated that almost a third of ocean fisheries

are being over-exploited.

The remarkable recovery of the herring here

demonstrates what can happen if a fishery is carefully managed.

Our maltreatment of the seas has many effects.

Some are predictable.

But there are others that are rather more surprising.

South-east Asia.

The coral reefs here are among the richest on the planet.

Marine biologist Steve Simpson is discovering how important sound is

to the animals that live in these bustling coral cities.

We're only now just realising, by listening underwater,

that the fish are making all these sounds.

They use sound to attract a mate, to try and scare away a predator.

You hear pops and grunts and gurgles and snaps.

POPPING

There's a whole language underwater

that we're only just starting to get a handle on.

BUBBLING AND SEALIFE CALLS

CHIRRUPING

Using an advanced, multi-directional hydrophone,

Steve is trying to make sense of this extraordinary chorus

by working out who is making which noise.

One fish is especially talkative.

LOW CHIRRUP AND POPPING

It's perhaps the reef's most famous resident, the clownfish.

While filming for the series,

we followed this particular family of saddle-back clownfish

as they searched for a suitable place to lay their eggs.

It's a noisy affair.

BUBBLING AND POPPING

LOW CHIRRUPING

For clownfish, sound really is everything.

They spend all day talking to each other.

You've got dominance and the submission,

you've got all the others calling to each other.

It seems that they also use sound...

..in protecting themselves

from the many predators that hunt around the reef...

..including coral trout.

Will this model trout fool the clownfish?

They react almost immediately.

RAPID POPPING

By mimicking a predator,

Steve manages to record their alarm calls without putting them at risk.

You can really hear the deeper pulsing sound

of the female as she tries to scare the coral trout away.

DEEP, RAPID POPPING

And all the little ones are just popping, "Pop, pop, pop,"

as if to say, "I'm still OK, I'm still alive!"

So they've got this real language of sounds that they're using

just to try and defend the colony against this coral trout.

But that discovery has led to a serious worry.

MOTOR DRONES

The fish were really popping away at the predator,

but, as soon as the boat came over, they looked completely distracted.

With all that noise, it completely changed how the fish were behaving.

Unable to make themselves heard above the noise of boats,

the family can't warn each other of danger

and so they are now vulnerable to attack.

When you think about how many boats are driving around, all the ships,

all of the offshore drilling, and all the noise that we're making

in the ocean, you realise just how much we're drowning out

this natural biological noise, robbing animals of their ability

to be able to talk to each other.

All this noise may have serious consequences for many reef fish

because their babies, as soon as they hatch, are swept out to sea.

There, they feed and grow until strong enough to swim back.

And to find the reef, they use sound.

They listen in, they eavesdrop to the noises that they can hear

and they use that to choose which reef they want to make their home.

But obviously because we're adding all this noise to the ocean,

it's a wonder whether they can even hear the reef at all.

SHIP'S HORN BOOMS AND ECHOES

Man-made noise is now everywhere in the ocean,

and it has an effect on marine creatures of all kinds...

..from tiny fish...

..to gigantic whales.

But Steve believes there are solutions.

Noise in the ocean is a real problem.

But it's something that we can control -

we can choose where we make the noise,

we can choose when we make the noise.

We can directly reduce the amount of noise that we make,

and we could start doing that today.

We're only now beginning to realise what an impact our noise

is having on the inhabitants of the ocean.

Other forms of pollution are only too familiar.

Since its invention some hundred years ago,

plastic has become an integral part of our daily lives.

But every year, some eight million tons of it ends up in the ocean

and there it can be lethal.

While filming Blue Planet II,

the crews found plastic in every ocean...

..even in the most remote locations.

PENGUINS CHATTER AND CALL

South Georgia.

900 miles North of Antarctica,

this isolated wilderness is the breeding place

for vast numbers of penguins and elephant seals.

SEALS GRUNT

It's also a favoured nesting site for the largest bird in the sky...

..the wandering albatross.

Here we learned of the extraordinary lengths aged parents go to

give their chicks the best chance of survival.

Each devoted parent travels thousands of miles

searching for fish and squid to feed their hungry chick.

But, despite all their efforts, the albatross colony here is in trouble.

Lucy Quinn is part of the British Antarctic Survey team

studying the birds here for the last 40 years.

It's only through looking at long-term studies

that you get a sense of these creatures,

and the albatrosses here have, over the past ten years, been in decline.

There are a number of possible reasons.

While foraging at sea, albatross can get entangled

and drowned by fishing gear...

..but Lucy is particularly alarmed

by what the parents are bringing back for their chick.

Albatrosses have the ability to cough up bits of food

that they can't digest,

and from that we can tell what they've been eating.

A healthy albatross chick in its diet

should really have things like squid,

so we can find the squid beaks that come out of the pellet,

and also things like fish, so we can find fish bones as well.

But these chicks are being fed something very different.

We have some plastic that this poor chick has had to bring up.

Plastic bag.

Here we have some food packaging, looks like rice.

Luckily for this chick,

he has managed to get this out of his stomach,

so fingers crossed he doesn't have any more plastic

left in there before he fledges.

For other chicks, plastic can be fatal.

Unfortunately, there was a plastic tooth-pick

that had actually gone through the stomach.

Something just as small as that has actually...

has managed to kill the bird. It's really sad to see.

Lucy collects and records what plastic she finds around the nests.

These are all items that were regurgitated just from last season.

And that's going to be a vast underestimation,

because that's just the ones that we happen to find.

There'll be many more that we never see being brought back.

To find out where all this rubbish is coming from,

Lucy and her team have attached GPS trackers to adult birds.

It's showing where they're going to find food for themselves

and to find food to bring back for their chicks.

It really shows us that they could be picking up plastic

from thousands of miles away.

Plastic's coming from either being dumped at sea,

or also from people's homes.

Plastic gets into the rivers

and then the rivers flow into the sea.

So this isn't just a problem around these remote parts -

this is happening world-wide,

and it's our rubbish that's going into the oceans,

and it's our problem that we need to solve.

In some parts of the ocean, it's estimated that there are now

over one million pieces of plastic for every square mile.

And we're only beginning to discover

just how seriously that affects marine life.

On the east coast of the United States,

researchers are investigating the mysterious deaths of young dolphins.

The team is led by Dr Leslie Hart.

It looks to be a young animal, maybe a little bit over a year.

So we're going to try to find out more information

on why this dolphin died.

Looking at young dolphins, the very young dolphins,

it's always heart-breaking.

Leslie takes tissue samples.

Their chemical analysis could provide crucial evidence.

We are often shocked by the high levels of toxins

that we detect in these animals.

These young calves are dying for a number of reasons.

But we suspect man-made toxins are playing a large role.

And plastic could be part of the problem.

Once in the ocean, plastic breaks down into tiny fragments,

micro plastics.

Along with all the industrial chemicals

that have drained into the ocean, these form a potentially toxic soup.

The really small organisms can mistake these tiny, tiny plastics

as food, then the larger organisms eat the plankton,

the larger fish eat the smaller fish and so on and so forth.

Dolphins are at the top of this food chain,

and it's now thought that pollutants may be building up in their tissues

to such a degree that a mother's contaminated milk

could kill her calf.

Industrial pollution and the discarding of plastic waste

must be tackled for the sake of all life in the ocean.

Around the world, people are now devoting their lives

to saving some of the most threatened sea creatures.

As here in the Caribbean.

Every year, on just a few islands, a remarkable event takes place.

As the sun sets, giant reptiles begin to emerge.

This magnificent creature, preparing...

Whoops!

..preparing to lay her eggs is the largest of all turtles,

a leatherback.

They can grow up to half a ton in weight

and they have an ancestry that goes back 100 million years,

to the age of the dinosaur.

But, in recent times, their numbers have fallen catastrophically.

Here, however, in the Caribbean, there is hope.

Leatherback turtles leave the sea

in order to lay their eggs in the dry sand.

But, out of water, these huge creatures

are easy targets for hunters.

In a small fishing village in Trinidad,

Len Peters has experienced this first-hand.

I grew up in a household where the presence of turtle meat was normal,

the fridge was always full of it.

Everybody, everybody harvested turtles, including my parents.

It's only when I became exposed to things that were being published

about leatherbacks were on the verge of extinction,

and nobody cares, that piqued my interest.

Len took the leatherbacks' future into his own hands.

He began patrolling the beach at night to protect the turtles,

a brave thing to do.

We were met with tremendous resistance -

people would pelt us at night.

I have had persons insult me, I've had persons curse me,

I've had persons physically try to wrestle me with a machete.

So it was really a hostile time back then.

If Len was going to save these turtles,

he needed to win over the whole community.

We had to find a way to get the villagers to benefit

from the presence of these animals.

He began to encourage tourists to visit the beach,

and trained some villagers to be their guides.

To help secure the turtles' future,

he took the message to the next generation.

Now, what's the largest size a leatherback can grow to?

Er, Charlene?

2,000 pounds?

That's correct, leatherbacks can grow to 2,000 pounds.

That's a big turtle.

Len's hard work paid off, and now attitudes have changed.

Just want to touch base on some of the things

we want to accomplish tonight.

It took us a while to reach out to the villagers.

But gradually we got them involved as well -

we got some of the poachers who would be hunting the animals

to be part of the conservation programme.

As well as protecting the adult turtles,

the team also collect any eggs that might be flooded at high tide.

If the eggs are laid too close to the sea,

we relocate the eggs and re-bury them.

Thanks to the efforts of this community,

these turtles have had an extraordinary change in fortune.

This is now thought to be

one of the densest leatherback nesting beaches in the world.

When we started at the height of the nesting season,

the numbers will be 30, 40 turtles.

A night. Now it's over 500.

So we have seen an increase from 40 turtles to 500 turtles a night

in just around 20 years.

Precious new hatchlings are also given a helping hand.

Any that emerge during the day

are collected to be released safely back to the sea,

away from hungry birds.

This little leatherback will have to face 1,000 hazards,

before it returns as an adult to this beach where it hatched,

and those dangers will be greatly increased

because of damage that we have done to the oceans.

Good luck, little leatherback.

Protecting breeding sites on beaches

may improve the fortune of some marine animals.

But safeguarding them while they roam the high seas

is much more difficult.

Out here, there is little protection.

Every night, thousands of miles of fishing lines,

laden with hooks, are set.

There's enough, it's said, to wrap twice around the world.

Nets large enough to engulf cathedrals

trap hundreds of tons of fish at a time.

Long-distance travellers, such as sharks, are particularly at risk.

It's estimated that tens of millions are killed every year,

including the biggest fish in the sea, the whale shark.

Shark biologist Jonathan Green is concerned

that time is running out for these extraordinary creatures.

We know that they're being fished, possibly at a massive rate.

They may be taken by the thousands, possibly tens of thousands a year.

If that is indeed true, we don't know how long

they can withstand that kind of fishing pressure.

To save them, Jonathan is trying to solve the mystery

of where they give birth.

And, for the first time, he has a clue as to where this might be.

Pregnant whale sharks are thought to be travelling

from across the Pacific Ocean to Darwin Island, in the Galapagos.

Jonathan is going to try

and attach a multi-sensor camera tag to a pregnant female.

OK, we good to go?

These sharks only stay in the area for a few days -

this may be his only chance.

Jonathan has to attach the tag

before the shark dives to dangerous depths.

The tag will remain on the giant's fin for two days

before it's automatically released.

Once retrieved, it reveals some unusual behaviour.

Beautiful, beautiful.

There's a silky rubbing up against the front, next to her eye.

The silky sharks are brushing up against her rough skin,

perhaps to scrape off parasites.

These predatory sharks make the surface waters

very unsafe places for young fish of any kind.

There is a surprise in store.

The tag's depth sensor reveals

that she dived to a depth of 600 metres.

But down there it's too dark for the camera.

The only way Jonathan can prove if they're giving birth

is to go down and look.

-RADIO:

-Deep Rover, Deep Rover Control -

you are clear to vent, clear to vent. Have a good dive.

Out of the gloom, a shape materialises.

Another massive whale shark.

Look at that, she's having a look at us, she's looking right at us!

She is huge!

And look at the belly - absolutely massive.

That's a large, pregnant female and she's sticking around,

she's staying around.

It goes to show we can follow them, we can follow them in a submarine.

She leads them down into the darkness.

-RADIO:

-Deep Rover Control, passing one-zero-zero metres descending.

Heading down, I think she accelerated slightly.

She's too fast.

And with a strong current running against them,

the sub can't keep up.

But, for the first time,

Jonathan can see for himself exactly where she's headed.

What specifically Darwin could provide is a safe refuge

for those newborn pups where predators can't access.

Perfect conditions for the formative years

of these ocean-travelling giants.

Ah! That was unbelievable.

Ah! Dream of a lifetime.

His discovery that pregnant whale sharks

are visiting this very deep patch of the sea floor

is strong evidence that this is indeed

where the giants produce their young.

If I can actually prove that they are giving birth in this area,

then we'll have the information necessary

to go to governments to actually say,

"You must preserve those routes that they're migrating through."

And then and only then can we really truly afford protection

to this beautiful ocean traveller.

Today, less than 1% of our international waters are protected.

And the creation of marine reserves is vital

if we're to safeguard the future of many ocean creatures.

It will require international cooperation.

But here, too, there is hope.

We can turn things round.

We've done so once before.

For centuries, the sea-going nations of the world hunted the great whales

until they were close to extinction,

and then, in 1986, those nations got together

and agreed to put a stop to commercial whaling.

Today, although a few nations continue to hunt whales,

some of the great whales are making a recovery.

In the tropical seas surrounding Sri Lanka,

there are stories of vast gatherings of whales.

When the civil war ended in 2009,

locals here were able once again to fish these waters.

There were soon reports of assemblies of sperm whales,

the likes of which had not been seen for centuries.

Marine guide Daya was determined to get to the truth

behind these fishermen's tales.

The fisherman told me there were lots of whales,

a little bit north from here.

They didn't actually tell me a number, but in big numbers.

Not ones or twos. Er...many.

It took him three years,

but eventually he found evidence to support these rumours.

We saw about 15 sperm whales go past us.

Then another pod came past us.

After about 40 went past me, I started counting.

Still they kept coming, so I lost count.

I estimated that we saw about 300 sperm whales.

Sperm whales were once killed in vast numbers,

and it's thought that if the slaughter had continued,

the species would be in danger of extermination.

But now, here at least, they are being seen in huge numbers.

I believe they come here to feed, mate, raise their young.

So this must be a holiday spot for them, you know?

At the moment, I don't know of any other place in the world

that sperm whales gather like this.

Although some whale populations are still in decline,

scenes like this prove that when sea-going nations come together,

they can achieve astonishing results.

But today the oceans face threats on a truly global scale.

The Great Barrier Reef...

..the largest coral reef system in the world.

Here, we filmed stories which reveal just how smart fish can be.

This ingenious tusk fish, for example,

used a favourite coral anvil to smash open shellfish.

This astonishing behaviour has been closely studied

by local scientist Alex Vail.

We call him Percy, Percy the Persistent,

because he took, like, an hour to open the first shell.

He must have hit it well over 50 times,

but he just kept on going and finally he got it open.

Alex grew up on the Great Barrier Reef,

on one of its more remote islands, Lizard.

He knows the reef intimately.

But in 2016, while he was filming for Blue Planet II,

Alex witnessed a catastrophe.

When we started filming, everything was pretty much fine,

all of the corals were basically healthy.

But, in the last few weeks, everything changed.

I have never seen anything like this before.

A combination of a warming ocean

and an unpredictable weather event called El Nino

raised sea temperatures to record levels...

..and this had a disastrous effect on the corals.

The heat causes reef-building corals to lose their nourishing algae,

exposing their white skeletons.

When temperatures remain high, bleached corals die off.

The bleaching this year has been the worst in history

for the Great Barrier Reef.

About 90% of the branching corals

on the reef out here at Lizard Island are dead.

It also has disastrous consequences

for the other creatures that live here.

Percy, swimming around out there,

the really sad thing is that his castle is starting to bleach.

If we lose our coral,

there's a chance we're going to lose our tusk fish.

It's incredibly sad to see areas

that you have dived on since you were a little kid

just turn to rubble.

I cried in my mask when I saw, you know,

some of the devastation from this bleaching.

In the last three years,

over two thirds of the world's coral reefs

are thought to have suffered from rises in ocean temperatures.

This is not the only challenge they face.

Research is revealing

how the fundamental chemistry of the ocean is changing.

Professor Chris Langdon shows me what this might mean

for the future of our seas

by pouring dilute acid over shells.

And how much more acidic is this than the present ocean?

This is more concentrated than the pH of the ocean,

but it accelerates the process so we can see something visually.

So what's happening is these shells,

they're made out of calcium carbonate,

and the acid is dissolving them,

and coral reefs are made out of the same material as these shells here.

But surely this is not happening in the ocean now, right now?

What we're seeing here is more dramatic

than what's happening in the ocean.

But the shells and the reefs are really, truly dissolving.

Coral reefs could be gone by the end of this century.

And the cause of this?

Carbon dioxide.

Dissolved in the seawater, it forms carbonic acid.

The more carbon dioxide in the atmosphere,

the more acidic the ocean becomes.

Evidence points to the burning of fossil fuels as the primary cause

for these increasing levels of carbon dioxide.

And this is man-made, beyond question?

Beyond question.

But Chris believes all is not lost.

All we have to do - I say "all" - is reduce our CO2 emissions.

We can switch to renewable fuels,

wind and solar instead of fossil fuels,

and so none of this has to devolve to the worst case.

And that could fix it?

Yeah, absolutely. So this future does not have to play out.

It's-it's up to us.

THUNDER CRACKS AND RUMBLES

As the climate changes and the seas warm,

our oceans are being seriously affected...

..and this is nowhere more apparent than at the poles.

Antarctica.

For the Blue Planet II team, this was their most ambitious expedition.

For the first time in history,

a manned submersible will try to dive to a depth of 1,000 metres

and reach the Antarctic seabed.

A true journey into the unknown.

-RADIO:

-Deep Rover, Deep Rover Control. Comms check, over.

SO, Rover. Hatch secure. Life support running.

Control Rover, passing four-zero metres, over.

Leading the team on this historic dive

is deep-sea scientist Jon Copley.

We get our first glimpse of this landscape...

..and the carpet of life around us is astounding.

That's beautiful.

Diving in a submersible gives Jon an entirely new understanding

of how this rich ecosystem works.

But it also offers him a unique opportunity

to investigate how the ocean here is changing.

While we're observing the marine life down there,

the subs are also recording what the environment's like,

so we're getting measurements of temperature, of salinity,

that's hopefully going to enable us to understand

the changes that are happening in this vital part of our planet.

To get a fuller picture,

Jon also lowers a deep-sea temperature probe.

His data is contributing to an international attempt

to chart the rise in both sea and air temperatures.

What shocks me about what all the data show

is how fast things are changing here.

We're headed into uncharted territory.

To truly comprehend the effect of the temperature increases here,

Jon takes to the skies.

From here, he can record the number and size of the icebergs

being produced as the ice shelves melt and break apart.

The 'bergs we're seeing all around us give you some idea

of how huge this process is that's taking place on the Antarctic.

As the floating shelves break up,

they allow water, which has been locked up

on land as ice for thousands of years, to empty into the sea.

And this is predicted to push up sea levels.

If the ice-shelves break up, then that opens the flood gates.

Ice on land flows faster into the sea

and that's what pushes up the sea levels.

So what's happening here right now affects all of us.

Already, cities like Miami here are under threat.

Scientists predict that, by the end of the century,

the sea levels could have risen by a metre or even two.

Were that to happen, parts of this city would certainly be submerged.

Around the world, hundreds of millions of people

live near the coast,

and, as sea levels rise, their lives will be seriously affected.

It's now clear that our actions

are having a significant impact on the world's oceans.

During the four years it took to make this series,

we've witnessed many of these changes first-hand.

But we've also worked alongside men and women

dedicating their lives to safeguarding the oceans' future.

The oceans provide us with oxygen, they regulate temperature,

they provide us with food and energy supplies

and it's unthinkable to have a world without a healthy ocean.

I still think we have the capability to change the manner in which

we're wasting the resources, in which we're poisoning our oceans

and we can look to a future with healthy oceans.

When I look forward, I believe that if what we are doing

can be duplicated just a little bit,

these animals will have a chance of surviving.

It comes down, I think, to us each taking responsibility

for the personal choices in our everyday lives,

that's all any of us can be expected to do

and it is those everyday choices that add up.

We are at a unique stage in our history.

Never before have we had such an awareness

of what we are doing to the planet...

..and never before have we had the power to do something about that.

Surely we have a responsibility to care for our blue planet.

The future of humanity,

and indeed all life on Earth, now depends on us.

To find out more about our oceans with this free poster, call...

..or go to...

..and follow the links to the Open University.