Original subtitles

tribe.

In the course of making Blue Planet 2, 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. HE SQUAWKS

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 fields.

The Blue Planet 2 team spent three years documenting this astonishing event.

Such a wealth of prey attracts predators in extraordinary numbers.

Orcas.

And humpback whales. HE SQUAWKS

But this migration hasn't always been so bountiful. Leif

Nogestad 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. ORCAS

SQUAWKS

Today, this is once again an immensely productive

fishery. Closely monitored by teams of scientists.

Marine biologist Yves Jourdan is one of the resident orca

experts. From 1982, orcas got protected in Norway, and we

have clearly one of the largest orca population 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, Yves 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. The 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 it

is not a scratch on the whale afterwards, which is something

we really like.

While studying the orcas, Yves 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 net. 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 Yves 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 fishermen

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 fishermen 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 attacking an orca, it's released and Yves collects it.

This tag is full of secrets, you know, because it has been

on the whale for several days and we just reveal exactly

what the whales have been doing. Pictures from

the tag reveal a hunting technique in detail.

They dive below the ball of fish.

And then backflip.

The powerful tail slap stuns the herring.

Yves 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 here 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.

Southeast Asia. The coral reefs are the most important

and the 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.

There's a whole language underwater that

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

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.

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

While filming for the series, we followed this particular

family of Saddleback clownfish as they searched for a

suitable place to lay their eggs.

It's a noisy affair.

The clownfish sound, really, is everything. They spend

all day talking to each other. You've got dominance in 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.

The clownfish are known to be the most dangerous fish including coral trout.

Will this model trout fool the clownfish?

They react almost immediately.

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. And all the little ones are just popping,

pop, pop, pop, as if to say, oh, my God, I'm going to die.

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.

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. 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.

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.

HEAVY METAL RUMBLING 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. HEAVY METAL RUMBLING

Since its invention some 100 years ago, plastic has become

an integral part of our daily lives. But every year, some

eight million tonnes of it ends up in the ocean. And there, it can be lethal.

While filming Blue Planet 2, the crews found plastic

in every ocean. Even in the most remote locations.

South Georgia.

900 miles north of Antarctica, this isolated wilderness is

the breeding place for vast numbers of penguins and elephant

seals. HEAVY METAL RUMBLING HEAVY METAL RUMBLING

It's also a favoured nesting site for the

largest bird in the sky. The wandering albatross.

HEAVY METAL RUMBLING Here we learned of the extraordinary

lengths aged parents go to give their chicks the best chance

of survival. HEAVY METAL RUMBLING Each devoted parent

travels thousands of miles searching for fish and squid to

feed their hungry chick. HEAVY METAL RUMBLING 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 over the past 10

years have 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 toothpick that had actually gone through the

stomach. Something just as small as that has actually

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 the nests, it's a problem around

these remote parts. This is happening worldwide, and it's

our rubbish that's going into the oceans. 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 heartbreaking.

Leslie takes tissue samples. Their chemical analysis could

provide crucial evidence. We have a very high probability

that it's a young dolphin. 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. Microplastics.

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, and 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 Industrial pollution and the discarding

of plastic waste must be tackled for the sake of all life in

the ocean.

INDUSTRIAL POLLUTION 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.

INDUSTRIAL POLLUTION 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 tonne 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 harvests a turtle, including my

parents. It's only when I became exposed to things that

were being published about leatherback and the verge of

extinction, and nobody cares, that piqued my interest. Len

took the leatherback's 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 have had person

curse me, I have had person physically try to harass me. I'm

a little 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 train some villagers to be their guides.

To help secure the turtle's future, he took the message

to the next generation. Now, what's the largest size a

leatherback can grow to? Er... Shani. 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. I just want to touch base on some of the things we

wanted 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 rebury 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 sea, the nesting

season, the numbers would 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 Greene 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 problem. 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're good to go?

These sharks only stay in the area for a few days. This may

be his only chance. He's going to try and find out where the

sharks are.

Jonathan has to attach the tag before the shark dives to dangerous depths.

He's going to try and find out where the sharks are.

The tag will remain on the giant's fin for

two days before it's automatically released.

Once retrieved, it reveals some unusual behaviour.

What beautiful, beautiful...

There's a silky rubbing up against the front. Next to a

rock. The silky is trying to find out where the sharks are.

The 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 centre 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.

Deep rover, deep rover, control. You are cleared

to vent. Cleared to vent. Have a good dive.

Out of the gloom, a shape materialises.

Another massive whale shark. Look at her. 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 staring around.

She's staring around.

It goes to show. We can follow them. We can follow them in the submarine.

She leads them down into the darkness.

Deep rover, control. Passing 100 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, she can. 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 them.

Perfect conditions for the formative years of these ocean -travelling giants.

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 around. 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 the great whales being caught

in the sea. There were also reports of assemblies of sperm

whales, the likes of which had not been seen for centuries.

Marine guide Dyer was determined to get to the truth behind

these fishermen's tales. The fishermen told me that there

are lots of whales a little bit north from here. They didn't

actually tell me a number, but in big numbers, not one or

two, many.

It took him three years, but eventually he found evidence to support these rumors.

We saw about 15 sperm whales go past us.

Then another boat came past us.

After about 40 went past me, I started counting.

Still, they kept coming, so I lost count. I estimated 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 seagoing 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 film stories which reveal just how smart fish can be.

This ingenious tuskfish, for example, used a

favourite coral anvil to smash open shellfish.

This astonishing behaviour has been closely studied by

local scientist Alex Phail. 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 2, 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 Niño 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 tuskfish. 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. So what's

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 the 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 natural or fossil fuels.

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

not to fix it. Yeah, absolutely. So this future

does not have to play out, it's up to us.

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. Yeah.

For the Blue Planet 2 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 meters and

reach the Antarctic seabed. A true journey into the unknown.

SO rover, hatch secure, life support running.

Control rover, passing 4, 0 meters, over.

Leading the team on this historic dive is deep sea scientist John 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 John 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, John 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, John 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 floodgates.

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 meter or even two. Were that to happen,

parts of this city would certainly be submerged.

Around the world, the world is changing. 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 firsthand.

But we've also worked alongside men and women, dedicating

their lives to safeguarding the ocean's 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.