Original subtitles

All this week we've experienced some of the most incredible ocean

wonders, and had some fantastic encounters with iconic

marine animals.

Tonight I'm in search of one of the

most spectacular whales, the humpback.

humpback. We are in Australia where our

our divers are getting ready to carry

carry out a live night dive to bring you

you a spectacular natural wonder, the

the fluorescent night show of the Great

Great Barrier Reef. I will be trying to

to dive with one of the most threatened

threatened and dramatic of all sharks,

sharks, the great hammerhead. Join us

us for all this and more on Blue Planet

Planet Live!

Welcome to Blue Planet Live. All

week we have stationed ourselves at marine

marine hotspots across the surface of

of the planet and putting our fingers

fingers on the pulse of the health of

of our oceans, accessing that to see precisely

precisely the problem is they are facing.

facing. During the course of this we have

have seen some spectacular wildlife, some

some truly fantastic things and I can

can promise you that tonight we will be

be seeing a lot more as well. Our mission

mission tonight is to throw forward into

into the future, to see what that is in

in store for our seas.

Over the past week we have dived

deep into our oceans, exploring above,

above, on and beneath the surface. We

We have revealed their wonders, explored

explored the challenges they are facing,

facing, and met the scientists going to

to extraordinary lengths to save them.

them. One important question remains.

remains. What does the future hold for

for our Blue Planet?

A very important question indeed and

to answer it this evening we are in three

three separate time zones on the surface

surface of that planet so where are we?

we? I have come 5000 miles from the UK

UK across the Atlantic Ocean and North

North America to the west coast of Mexico

Mexico and the Baja Peninsula. On the

the inside you have the Sea of Cortez

Cortez and on the outside the Pacific

Pacific Ocean and it is because the other

other side of that ocean, 10,000 miles

miles away from here, that we can join

join Liz on the Great Barrier Reef. Thank

Thank you, Chris. We are on Heron Island

Island just off the jetty here and because

because the clocks have gone forward where

where you guys are in the UK, it is still

still dark here just before dawn and I

I will be showing you more extraordinary

extraordinary work that scientists here

here are carrying out to safeguard the

the future of our reefs and we will be

be finding out what the divers are doing

doing in the water at this time of night.

night. Meanwhile, 9000 miles away from

from me, Steve is in a shark century off

off the Bahamas. Yes, that's right! I'm

I'm in the shark sanctuary of the Bahamas

Bahamas and after a week of high winds

winds and cloudy seas, we have finally

finally got our weather window. We have

have a lot of sharks but are there any

any hammerheads? Only one way to find

find out!

Yes, I have moved since the last

time I was with you, we were up in the

the Loretto National Park looking for

for blue whales but we have now come to

to the southern tip of the peninsula so

so I have the sea of Cortez on this site

site and the Pacific Ocean on that site

site and also, live we have humpback whales!

whales! This is coming to you live from

from our chopper with Larry and Matt up

up there and it looked like those whales

whales had just gone down, that is whales

whales for you! Don't worry, they will

will be back up. We have come to this

this particular spot because it is a humpback

humpback whale highway. They have spent

spent their winter in the Sea of Cortez

Cortez and they are moving past this area

area to head back out into the Pacific

Pacific Ocean. We have seen mothers and

and calves, yesterday we got a calf actually

actually reaching almost learning the

the technique, a little playful humpback

humpback calf only a few months old but

but already about six metres long and

and probably weighing in just under three

three tons and growing rapidly on a diet

diet of its mother 's milk. That looks

looks to me like a calf having some fun

fun in the sun even if there is a learning

learning purpose. But where have these

these animals come from? They began their

their journey to this part of the world

world a long time ago. They were up in

in the Arctic summer and have travelled

travelled all the way from the Aleutian

Aleutian Islands, from a lack -- from

from Alaska, the vast majority from Monterey

Monterey Bay off California become all

all the way down the West Coast of the

the States and Mexico and come here for

for the winter in order to give birth

birth and to breed. But to facilitate

facilitate that, because they are fasting

fasting when they are here, they have

have to spend a lot of time eating when

when they are in those Arctic waters and

and they go up there because of the enormous

enormous productivity all of the plankton

plankton that fuels huge shoals of fish.

fish. They will also catch salmon, Heron,

Heron, haddock, and they will swallow

swallow the water and filter it to save

save out all of the food. They can put

put 95% of the energy they gain when they

they are feeding up there in the Arctic

Arctic into blubber so that... Hold on!

on! We have got the whale on the surface

surface again. This is a live whale, oh

oh yes! Superb! There you can see the

the animal still beneath the surface.

surface. Presumably this is the mother

mother or the calf, yes, this is the adult

adult so the calf must still be there

there somewhere. I'm pleased at this point

point to be able to rejoin Geraldine.

Geraldine. Look at this! It is amazing.

amazing. Absolutely spectacular. That

That is 100%! But you have cheated! You

You have cheated on your predictions!

predictions! But this is a good news story

story not just for these whales but humpbacks

humpbacks generally because the wailing

wailing period of the 19th and 20th century

century when we took out about 3 million

million of these animals, the species

species has bounced back. Yes, globally,

globally, a conservative estimate is 100,000

100,000 humpback whales. In these waters,

waters, around 5000 visit this area. The

The resilience of the species has astonished

astonished researchers worldwide. They

They think through serpents that if there

there were 125,000 come back whales before

before it started so it is remarkable

remarkable they have come back to that

that level -- through studies. But the

the thing is, these animals here now are

are in the process of leaving. They have

have been breeding here as well? This

This is where they come to breed and they

they also exhibit courtship behaviour.

behaviour. I'm glad you said that because

because yesterday we went out and we saw

saw some courtship behaviour and it had

had me literally jumping out of my skin!

skin! Look at this! Come on, whales. Just

Just here would be nice. Oh! Oh! My wish

wish came true! Unbelievable! Here, under

under the water alongside us, I can see

see them.

We have more animals out here, at

least another two or three out there.

there. One, two, three, four, five, six,

six, may be seven animals in this group

group now. Could it be that the one in

in the front is a female being pursued

pursued by a number of whales questioning

questioning humpback mating runs or heat

heat runs are initiated by a female who

who signals she might be ready to mate.

mate. The female will lead the run whilst

whilst the males compete to knock each

each other out. This is the biggest courtship

courtship contest on the planet. There

There is so much energy being expended

expended here, they are so close together,

together, there is jostling going on and

and sometimes when they are diving you

you can see one animal is being pushed.

pushed. Look at this! The males blow a

a bubble curtain is to try to disorientate

disorientate competitors. And open up

up their massive pectoral fins to try

try to force others out of the race. You

You can see all of the scarring on the

the backs where they have been rubbing

rubbing each other with those barnacles

barnacles which we think they might actually

actually use as weapons, when they are

are fighting. The biggest male stays closest

closest to the female, doing everything

everything he can to stop the others from

from getting too close. Did you hear that?!

that?! That sounded like a bull elephant!

elephant! And that one. I have never heard

heard that from these animals before.

before. These battles can last for several

several hours and cover up to 20 miles.

miles. Until finally there is just one

one winner. Exhausted, the last male swimming

swimming will escort the female until

until it is time to mate. This really

really is a whale bonanza, a humpback

humpback whale bonanza.

It is not often you can use the word

bonanza in conjunction with whales! I

I was so excited I nearly burst but rest

rest assured we were not breaking any

any of the whale watching protocols, the

the whales were coming to us. But those

those males, how do they find a female?

female? I know they are large, 50 metres

metres long and weighing 30 tons but how

how do they find a female in the past

past ocean? The answer is a song and on

on Thursday I sent you a little quiz.

quiz. What was the single largest pressing

pressing of an LP in history? It wasn't

wasn't the Rolling Stones or the Beatles

Beatles but in 1979 a version of this,

this, 10 million copies were printed for

for National Geographic magazine in 25

25 languages. When you come back to us

us live, we will be trying to record and

and listen to the song of a humpback whale.

whale. This is what it sounds like...

like... WHALE SONG. You might be fantasising

fantasising about seeing Lady Gaga in

in Vegas but we are going to bring you

you a humpback whale live on this programme!

programme! My confidence is soaring now,

now, not least because I'm looking at

at a live picture of one and all I have

have to do is tempt it into singing! But

But let's go over to Liz in Australia

Australia who is also hoping to witness

witness something quite extraordinary.

extraordinary. I am sold on that! Whale

Whale sounds over Lady Gaga every time.

time. On Heron Island we are on a glass

glass bottom boat just off the jetty on

on the Great Barrier Reef and because

because the sun is yet to rise here, it

it is the perfect opportunity to bring

bring you an incredible spectacle from

from the coral reefs themselves. Our divers

divers are in the water shining a special

special blue light on the corals under

under the cover of darkness which shows

shows that these incredible colours coming

coming from the little coral animals themselves

themselves and to find out more, I am

am joined by Anya Salih from Western Sydney

Sydney University. Tell us what they are

are doing when they are emitting these

these almost supernatural lights and colours?

colours? Corals live in shallow, sunlit

sunlit waters and they control the light

light for the photos in the S of the symbiotic

symbiotic algae that live inside them

them and give them through -- photosynthesis.

photosynthesis. But too much light can

can damage the corals and they use the

the fluorescent colours to control the

the light energy reaching the algae so

so they don't damage them. Beautiful,

Beautiful, we have some in the tank here

here to show you what you are talking

talking about. These beautiful green fluorescent

fluorescent colours they are emitting

emitting it is basically testament to

to the coral protecting the algae and

and themselves essentially. We have beautiful

beautiful images from the diverse, thank

thank you to Mike and John for these incredible

incredible images of the reef just outside.

outside. Does it mean that when corals

corals are emitting these colours, they

they are essentially able to protect themselves

themselves from some of the damaging effects

effects of climate change? That's right.

right. The when there is too much light

light and the temperature increases in

in the sea water, the fluorescent colours

colours in the corals can mitigate some

some of the damage, some of the effects.

effects. Not all but it goes to show what

what capabilities these little corals

corals are able to evolve on their own

own to protect themselves. It is quite

quite extraordinary. How do these new

new discoveries about corals help science

science and technology? What are you researching?

researching? We are learning a lot from

from corals. For example, the efficiency

efficiency of energy transfer in these

these fluorescent colours that corals

corals have is so high that we are learning

learning how to improve solar cell and

and solar panel technologies. The current

current solar panels have less than 50%

50% efficiency, which means the conversion

conversion of light into electrical power...

power... Look at that, a total live on

on our cameras at this time of night,

night, just before dawn, wandering amongst

amongst these beautiful corals that are

are not only protecting themselves but

but helping scientists find solutions

solutions to the very problems we are

are imposing on them it is such a beautiful

beautiful site for this time of the morning!

morning! Nature, finding solutions to

to all of our issues, that is a beautiful

beautiful thing to end on. Thank you for

for joining us. It is back over to Steve

Steve in the Bahamas who is in his element

element because he is diving with some

some of the most beautiful animals on

on the planet.

Well, yes, I have a ringside seat at

what has to be one of the greatest things

things I have ever seen. We have dozens

dozens of sharks around us. Most are like

like this one here. It is a nurse shark.

shark. They are quite dopey -looking.

-looking. They hang out on the bottom

bottom and they get their nurse name from

from the way they suck up their food using

using vacuum suction from the sea bed.

bed. But this creature, that's heading

heading towards us now, that really is

is the main event. It's a great hammerhead.

hammerhead. There are at least three of

of them around us right now. And while

while the nurse sharks are quite dopey,

dopey, just hanging out on the bottom,

bottom, this is a far more targeted predator.

predator. You can see it moving with its

its head just shaking from side to side,

side, sensing for food. It's Mallett -like

-like head, the most distinctive thing

thing about the animal, and it's probably

probably evolved as a way of spreading

spreading out in senses. . We have sharks

sharks coming in behind me. That is a

a smaller male shark.

a smaller male shark. Circling around

around trying to find the source of the

the food. They have senses that allow

allow them to target the weak electrical

electrical fields that are given off by

by the moving muscles of their prey. It

It is a super sense that sharks have,

have, and the hammerhead's mallet like

like head, that cephalofoil., spreads

spreads out the senses, allowing them

them to since moving muscles of a pre-.

pre-. It is almost like they see a moving

moving aura around their prey. The hammerhead

hammerhead sharks movement is much more

more targeted than the nurse sharks. Absolutely

Absolutely extraordinary. Other than the

the head, the most distinctive thing about

about them is probably that extraordinary

extraordinary dorsal fin. Huge, tall and

and curved. It's also one of the things

things that makes them most targeted by

by the shark fin trade. A

by the shark fin trade. A fin of that

that size is incredibly valuable. Here

Here comes the larger animal, probably

probably sensing our feed. We have a bucket

bucket full of fish. It's common practice

practice in the Bahamas to feed these

these sharks. As it comes in to wards

wards the food, you can see the mouth

mouth on the underside filled with thin

thin needlelike teeth, that are perfect

perfect for catching its fish and Ray

Ray prey. They have been seen using that

that hammerhead to press stingrays down

down onto the bottom and they will use

use their whole body to tear chunks out

out of their food. They are often found

found with dozens of stingrays embedded

embedded in their mouths. We have a lot

lot more time down here with these incredible

incredible animals. Blue Planet II showed

showed sperm whales off Dominica, some

some incredible images. But since then,

then, in the years that followed, technological

technological advances have enabled us

us to go one stage further.

Sperm whales are highly social

animals. They have the biggest brains

brains in the world and they live in tight

tight family units.

But despite these close bonds,

research in the last decade has found

found their numbers are in decline. One

One in three babies doesn't make it to

to their first birthday. We are losing

losing adult females faster than we can

can explain. Shane runs the Dominique

Dominique sperm whale project in the Caribbean.

Caribbean. He's trying to get to the bottom

bottom of why. Most of the ocean is dark

dark and humans have only explored about

about 5%. We know very little of the part

part of the world that sperm whales live

live in every day. To shed light on their

their lives below the surface, Shane uses

uses multi-sensor tags with cameras that

that he sticks onto the back of the whales.

whales. We have made a lot of assumptions

assumptions about how sperm whales behave

behave based on what we see at the surface,

surface, but with new technology we are

are getting a first-hand look at what

what it is actually like down there. For

For Blue Planet II he filmed an adult

adult female searching and diving for

for squid. But around 200 metres down,

down, we were plunged into darkness, and

and we could only hear the sound of the

the whale's clicks. Now, two years on,

on, we have teamed up with Shane and the

the latest camera tagging technology.

technology. Not only is this one designed

designed to cope with the crushing depths,

depths, more importantly it has lights

lights to illuminate the deep. We are

are hoping that for the first time ever

ever we will get a glimpse of what these

these whales see and do during their deepest

deepest dives. Where are the whales, Kevin?

Kevin? Get us closer. But attaching a

a tag to a 12 metre long rail is not easy.

easy. Sperm whales can disappear for almost

almost an hour when they died. -- when

when they dive.

Hang on.

Hang on. We got that on. Despite a

fight, the tag doesn't hurt the whale.

whale. It's only on-board for around six

six short hours but what it records could

could provide scientific insight.

could provide scientific insight. There

There is the baby! Wow. The calf has followed

followed its mother into the deep. This

This has never been seen before. Shane

Shane had suspected that baby Wales might

might follow adults into the gloom, but

but so far he'd only ever heard their

their clicks in the dark. It's something

something I could never have hoped to

to have seen 15 years ago when we started

started the project. The footage might

might not look like much, but it's revealed

revealed that calves make deep dives much

much earlier in life than first thought,

thought, which could suggest they are

are supplementing their diet of milk with

with squid. This new insight needs a lot

lot more investigation, but it could be

be a vital clue as to why we are losing

losing sperm whales.

We are back on the Baja Peninsula

and I am pleased to take you live to more

more pictures of the humpback whales as

as they move from the Sea of Cortez into

into the Pacific Ocean. This one is slapping

slapping its tail, a means of communication.

communication. They use their tails and

and pectoral fins to slap the surface

surface of the water. I can't see the

the pictures myself right now. This could

could be a male, or a female having fun.

fun. It could be a female and calf that

that we saw earlier, teaching the young

young calf these antics. We want to get

get into some humpback whale song now.

now. I've been joined by Nico Ransome

Ransome from Murdoch University, who has

has a hydrophone. We can drop this in.

in. This should enable us to listen to

to whale song. What sort of distance?

distance? Probably from around three kilometres,

kilometres, whale song in shallow and

and coastal areas like breeding grounds

grounds travels up to ten kilometres.

kilometres. Do you think there is a chance

chance we will hear that tail slapping?

It's too far away. Unfortunately

not. There is a distant Wales singing

singing right now. I can hear a male singing.

singing. Are you sure? Can't you hear

hear it? I have people talking in my ear

ear and my hearing isn't particularly

particularly good was not what we do have

have live humpback whale song. Truly superb.

superb. That song is incredibly complex.

complex. Structured in units and themes,

themes, songs and song cycles. Exactly.

Exactly. It's only the males that same...

same... And we just had a very high pitched

pitched part of the song. Only the males

males sing, and only on breeding grounds.

grounds. 24 hours per day, seven days

days a week, throughout breeding season,

season, if you put down a hydrophone like

like this then you will hear the males

males are singing. These noises are not

not random, they are very specific noises

noises in a set order. All the males in

in this population sing the same song.

song. We are hearing the latest hit of

of the Mexican humpback whales. This is

is the most up-to-date song of the male

male humpback whales of Mexico. They will

will have to pump it up to get on the

the charts. The intricacies of the song

song are such, they almost create it so

so that it can be copied and learned by

by other whales. It's constantly changing.

changing. One whale will add one bit and

and another whale will add another bit,

bit, so the song is constantly evolving.

evolving. At the same time, all the whales

whales should be singing the same basic

basic song. Your work, listening to the

the song, is about informing conservation.

conservation. How does that work, aside

aside from adding to science, it's about

about informing better conservation. My

My study is showing the threat of shipping

shipping in the Pacific. First we are

are trying to find the highest densities

densities of humpback whales to say where

where we should be protecting them, where

where we shouldn't be putting shipping

shipping lanes, not only to not hit them,

them, but also so this noise doesn't get

get masked. So the humpback whales can

can hear each other, find each other and

and successfully reproduce. And hopefully

hopefully they continue to recover from

from the damage we did to them. We don't

don't want to re-enact any of that. We

We don't want them not singing and hearing

hearing clearly. We now have footage of

of a male humpback whale singing. They

They hang in the water. The songs themselves

themselves last between five and 30 minutes,

minutes, but the song cycle can go on

on all day. Hanging in the water there,

there, putting out this extraordinary

extraordinary song. If you speed to the

the song up, it sounds like a nightingale.

nightingale. If you slow down the nightingale,

nightingale, it sounds a bit like a whale

whale and there is a definite musicality

musicality to it. Even artistic flourishes.

flourishes. It could be these humpback

humpback whales are being artistically

artistically creative in their construction

construction of their songs. But of course,

course, we would need more science to

to prove that is the case was that we

we can go back to Liz who is hoping to

to hear an extraordinary underwater concert

concert of her own.

Gosh, how glorious are these sounds

of the whales, utterly mesmerising to

to stop one of the most thrilling parts

parts of my journey here on Heron Island

Island has undoubtedly been following

following the work of scientists and the

the research they are carrying out to

to give our coral reefs a fighting chance.

chance. And the sounds of the oceans go

go far beyond the sounds of those majestic

majestic Wales. As we saw on Blue Planet

Planet II, the reefs are alive with noises.

noises. -- make those majestic whales.

whales. All those animals communicating

communicating with each other to find

find mates and hunt for food. We have

have a hydrophone that we can put in the

the water now. We will see what the reef

reef sounds like before dawn.

We can hear all the little clicks

and groans and squeaks. It's the most

most mesmerising soundscape. It goes to

to show how different the reefs are now

now scientists are helping us to better

better understand them. This is where

where it gets super fascinating. Doctor

Doctor Steve Simpson from the University

University of Exeter has been listening

listening to these sounds for many years,

years, and he's getting super creative

creative and using those sounds to recolonise

recolonise and restore degraded coral

coral reefs.

In Blue Planet II we met an

incredible tusk fish, who they revealed

revealed used tools. He became known as

as Percy. But we also saw the devastation

devastation on that same reef. It's something

something that marine biologists Steve

Steve Simpson witnessed first hand. The

The reef died in front of our eyes and

and we saw the fish leave. The coral was

was crumbling down into the sea bed. We

We know climate change is probably the

the biggest impact on coral reefs. Now

Now he is working to restore the reef

reef and bring the fish like Percy back.

back. We are working with coral reef restoration

restoration projects. They build these

these large artificial structures and

and start growing corals on them. The

The corals grow but the fish are not there.

there. We need to get the fish in for

for it to work. Having already spent almost

almost 20 years recording the sounds in

in our oceans, Steve wondered whether

whether he could use sound to encourage

encourage the fish back.

All these animals live in an

acoustic world, everything is using sound

sound as a way of finding a habitat to

to live in. If we can recreate that, we

we can get that recovery to happen much

much faster. But in order to attract the

the fish back, they first need to find

find out what sound is the fish prefer.

prefer. To do this, Steve has devised

devised a chamber with a speaker at each

each end. Each spigot then plays different

different recordings from different reefs.

reefs. -- each speaker in the dark, fish

fish are released into the chamber and

and can swim either sound. By repeating

repeating this hundreds of times, Steve

Steve and his team can record which sounds

sounds attract which species. The more

more we explore this, the more we are

are finding different fish have different

different references at different stages

stages in their lives. We have to build

build a whole repertoire of sounds, a

a whole library of different recordings.

recordings. If we know we are trying to

to bring in a certain species, we can

can play different tracks. We are working

working out how much we can be the conductor

conductor of this orchestra but the orchestra

orchestra is not there, we are trying

trying to pretend it is there and tricked

tricked them into coming into these areas

areas so they can be part of the recovery

recovery that is missing. We have got

got to keep these reefs alive. We have

have got to be throwing them lifelines

lifelines to give them every opportunity

opportunity as one of the greatest wonders

wonders on the earth. Isn't that the most

most beautiful description of science

science in action? Our understanding of

of the natural world and how to protect

protect it. Steve is finding out that

that the sound of snapping shrimp, those

those little clicks, tempt back the early

early young stages of fish that need those

those little boroughs of the snapping

snapping shrimp make to grow and and he

he is re-colonising the reefs step-by-step.

step-by-step. Just incredible and it is

is that kind of creativity and thinking

thinking outside the box that can really

really help the reefs survived. That includes

includes the work Peter Harrison who we

we met earlier this week as he was kind

kind enough to allow me to join him on

on one of his test site just off Heron

Heron Island where he is carrying out

out coral IVF and it was such a thrill

thrill to you measure these new little

little corals sprouting up so thank you

you so much. Tell me how you found those

those reefs to look after when you came

came here first in 2016? We are thrilled

thrilled at what we have seen. The corals

corals are growing well and they are looking

looking really healthy. Within a couple

couple of years they will be breathing

breathing size. How are you rolling this

this out and where else are you carrying

carrying out this incredible research

research and how happy are you with results

results so far? So far we have looked

looked at three different reef systems

systems in the Great Barrier Reef and

and six different areas in the Philippines

Philippines and the work in the Philippines

Philippines is really exciting because

because we have grown for the first time

time in the world from larvae, microscopic

microscopic larvae settling on the reef

reef through to dinner plate sized corals.

corals. That is the Philippines you're

you're saying and we are seeing that the

the fish have started to come back into

into these restored sites. Those corals,

corals, when they get to this size, are

are reproductive so we have closed the

the life cycle. Even more exciting, in

in the second generation we have got even

even faster growth rates so they are growing

growing through to reproductive size within

within two years and that's a world record.

record. That is incredible, how does it

it feel to see the fruits of your labour

labour and the success about? It must

must be incredible after all that hard

hard work. We're really thrilled by the

the outcomes and what we now know is that

that this can be scaled to much larger

larger scales, and applied onto many a

a bit reef systems around the world. What

What we want to do now is start using

using technology to help us. What we will

will do is adapt an underwater robot to

to deliver larvae at larger scales on

on the reef and we think we should be

be to get them to hit the scales in the

the next few weeks and eventually onto

onto kilometre scales. They can be kitted

kitted out especially for you to help

help spread the larvae which is amazing

amazing how technology can help you scale

scale up your work. The work that you

you and other scientists are carrying

carrying out on the reefs is nothing short

short of heroic but what support do you

you need so that all of this is not in

in vain? Yes, we are trying to restore

restore reef systems now but we are only

only able to buy time if we can manage

manage climate change. What we need is

is real action on climate change, we need

need all individuals, families and communities

communities to get involved. Because we

we only have one blue planet, it is our

our essential life support system and

and we have to protect it far better than

than we are doing at the moment. All levels

levels of society responsible for our

our planet, that is without question.

question. And all of the information that

that scientists are gathering to better

better understand what our marine life

life needs to helping to continue to inform

inform how to better protect our blue

blue planet. One of our teams met up with

with a scientist who is making new discoveries

discoveries about a very special shark

shark indeed.

Six miles off the coast of the

island of Andros in the Bahamas, a naval

naval boy has become a magnet for one

one oceanic wonder. This lone beacon is

is a big draw for passing travellers.

travellers. Providing shelter for schools

schools of fish. Which attract the hunters.

hunters. Top of the food chain out here

here are these, silky sharks.

They get their name from the silky

sheen of their skin.

So little is known about the

migrations of these open ocean drifters.

drifters. When shark biologist Kristin

Kristin Gutteridge heard rumours of this

this location, it was an opportunity for

for him to uncover the secrets -- Triston.

Triston. Which might just help protect

protect these frightened sharks.

protect these frightened sharks. These

These silky sharks are a completely different

different type of animal. They have this

this curious, bold personality that is

is a bit intoxicating. I love it. This

This inquisitiveness is this shark's Achilles'

Achilles' heel. Silky sharks are in trouble

trouble globally. In fact, silky shot

shot of the second highest court shark

shark species in the world. Industrial

Industrial scale fishing often uses floating

floating objects, working just like the

the naval buoy to help attract an aggregate

aggregate fish like tuna in the open ocean.

ocean. But they don't just attract tuna.

tuna. Every year, hundreds of thousands

thousands of silky sharks get accidentally

accidentally caught. For a fish that grows

grows slowly, mature late, and produces

produces few young, these losses have

have caused a 90% decline in some populations.

populations. I see the evidence of the

the pressures that these animals are under

under from the hooks in their mouths and

and the wire coming out of it. You can

can see these sharks are in trouble. They

They have a lot to deal with out in the

the open ocean on top of just surviving,

surviving, they had to survive this fishing

fishing pressure as well.

fishing pressure as well. Tristan wants

wants to find out exactly where these

these sharks are troubling to understand

understand where they might be at greatest

greatest risk but to do that he has got

got to catch one. One method that we can

can use to catch silky sharks is you can

can actually bend the top of the

can actually bend the top of the tale

tale over and it sends them into this

this kind of bizarre trancelike state

state and if you turn them upside down

down at the same time, they are almost

almost playing dead, they are just out.

out. It's not fully understood why but

but many shark species and that this trancelike

trancelike state called tonic immobility

immobility when upside down, enabling

enabling the team to tether the shark

shark for its safety and theirs. And to

to discover the great journeys these sharks

sharks make, a satellite tag is affixed

affixed to its dorsal fin. Every five

five minutes, this tag will record important

important information about where this

this shark is including depth, light levels,

levels, and water temperature. And in

in 30 days, it will release from the wire,

wire, pop to the surface and start sending

sending a stream of vital data to Tristan.

Tristan. They deserve to be on this planet

planet like us, like anything and they

they deserve to be here. As humans, we

we should be responsible. It is critical

critical that we learn more about these

these animals and it is critical that

that we protect them.

Everything that was said that about

those silky sharks is also true about

about great hammerheads. When you see

see this many sharks around you in one

one place, it is very easy to forget the

the challenges that these animals are

are facing around the world. We are taking

taking as many as 100 million sharks from

from the world's oceans everything all

all year, many of those simply taken for

for their fins. It cannot be sustained.

sustained. I want this spectacle to be

be going on for many years to come. And,

And, unfortunately, our actions are making

making that less and less likely. It is

is also worth remembering that great hammerheads,

hammerheads, although they may look fierce,

fierce, have never had a recorded human

human fatality. Not ever. Since records

records began in 1580. They were talking

talking about the tagging of sharks and

and that is critically important. The

The scientists I have been working with

with him in the Bahamas at Bimini Sharklab

Sharklab had been tagging these great

great hammerheads and finding out where

where they go.

where they go. Because, until very recently,

recently, that was a complete mystery.

mystery. And we are now starting to learn

learn about the migrations of these majestic

majestic animals. When you look around,

around, you will see that quite a few

few of them have got tags and the scientists

scientists have at least 30 individuals

individuals that they know by name. And

And not just by name but by personality

personality and character and behaviour.

behaviour. One coming up right behind

behind you, small male. Even in the short

short time since I have been here, I have

have been starting to get to know the

the individual personalities here. You

You might not think of a shark as having

having a personality but they very much

much do. Some of them are quite bold and

and dramatic and others are real gentle

gentle giants. And for the scientists

scientists here, it is a big moment in

in the winter when the hammerheads start

start returning. It is a chance to see

see old friends for the first time. There

There is a moment of excitement when an

an older shark comes back and they see

see it and that moment of sadness when

when one does not

when one does not come back, because their

their second they leave these safe waters,

waters, the shark sanctuary of the Bahamas,

Bahamas, and head out into the open ocean,

ocean, then they are fair game for just

just about anything. I have one coming

coming up behind me here. There are millions

millions of longline hooks trying to catch

catch these sharks. And their chances

chances of survival are very, very slim,

slim, unless we all come together to fight

fight their corner. It is a highly migratory

migratory species and they need a lot

lot of countries to come together to work

work for their future survival. While

While I'm here enjoying this fabulous

fabulous spectacle, Chris is on the search

search for ocean giants.

Steve Backshall, what a

professional! The redoubtable Steve Backshall!

Backshall! He is just beneath the surface,

surface, I am on the surface of the ocean,

ocean, these are relatively easy places

places to explore but if we go any deeper,

deeper, we need some specialist kit and

and this week we have been partnering

partnering with the Woods Hole oceanographic

oceanographic Institute and their submarine,

submarine, Albion. They took it off the

the coast of California to explore an

an undersea mountain and they made an

an extraordinary discovery. Just look

look at this. Deep down beneath the surface

surface they found this octopus brooding

brooding site. These are female octopuses

octopuses who have got their eggs and

and we think, there is so much more to

to be learned, this is the first time

time they have seen it but we think they

they are moved here because the water

water is slightly warmer. They do have

have to stick with those eggs to make

make sure they are aerated and they can

can do this, depending on the temperature

temperature and how much oxygen there

there is, for up to ten weeks.

You can see one of the animals free

swimming in the water, these extraordinary

extraordinary octopus. This really is

is a remarkable discovery, showing us

us all the time that there is so much

much more to be learnt about the creatures

creatures that live in these deep oceans.

oceans. They are extraordinary in their

their shapes and forms and life cycles.

cycles. I am perversely rather pleased

pleased I can't tell you the names of

of these creatures. Sometimes just looking

looking at them and enjoying their simple

simple beauty is enough to stimulate us

us in order to want to try and conserve

conserve them. A couple of months ago,

ago, the very same Alvin was on another

another expedition, this time piloted

piloted by a different scientist altogether,

altogether, Eric Cortez from the Schmidt

Schmidt Ocean Institute in the United

United States and he was off Costa Rica

Rica exploring another undersea mountain.

We are here on the RV Atlantis to

survey a series of seamounts that have

have never been explored before. The deep

deep sea is on average a couple of miles

miles deep. These rise a kilometre or

or more up off the sea floor. They are

are sort of like islands out in the middle

middle of nowhere. And like islands on

on land, seamounts isolate the animals

animals that live there, making some of

of their inhabitants unique. From deep

deep sea sponges to yeti crabs and sea

sea pigs. Living on the pitch dark, these

these creatures are some of the strangest

strangest on our planet.

Today's ten hour dive will take Eric

over 2000 metres down into the unknown.

unknown. 150 metres, thank you.

Everything gets dark as you descend,

and then you feel like you're on another

another planet. It's another world down

down there. Wow, look at that. At depth

depth that would crush your organs, safely

safely inside Alvin, Eric reveals cites

cites no human has ever seen before. I've

I've had a love of the ocean since I was

was a little kid. It's one of the best

best feelings in the world to discover

discover something new, see something

something you know that no one has ever

ever seen before. For a long time it was

was felt nothing could live down there,

there, below where light can penetrate.

penetrate. As we learn more and more about

about the organisms living up the steps,

steps, we also learn more and more about

about their connections to the surface.

surface. To chart what is down here, the

the team carefully take a small number

number of samples on each mission. Every

Every dive we do, we come up with something

something new. It's an exciting thing

thing to be a part of. By charting unexplored

unexplored areas like this, Eric is highlighting

highlighting the importance of seamounts.

seamounts. Aiming to create a marine protected

protected area. This will limit fishing

fishing and other damaging activities.

activities. And protect the exceptional

exceptional creatures that live in these

these waters. If there are human impacts

impacts that are happening further offshore

offshore and deeper on these seamounts,

seamounts, that can have effects that

that could range from across the globe.

globe. Effects

Effects we don't understand yet. It's

It's vital we protect these ecosystems,

ecosystems, and the only way we can protect

protect them as if we fully understand

understand and explore them.

Incredible stuff, and it is such a

powerful idea to know that even now in

in 2019, there are still parts of our

our planet that we barely know anything

anything about. That's also true of these

these sharks. So much about their secret

secret lives that we really are yet to

to understand. That's one of the reasons

reasons why if you are a young person

person out there, and you are looking

looking for a way to change the world,

world, become a marine biologist. You

You could be a huge part of making sure

sure that animals like this have a future.

future. It's also why I have to salute

salute all the scientists we have been

been working with here in Bimini shark

shark lab and all the people working to

to make sure they have a future. It's

It's a shame these animals have to rely

rely on us, but they do now. And if all

all of the world Cross ocean oceans adjoin,

adjoin, they are all connected, then this

this is our back as well. It's up to us

us to do our bit to make sure it's as

as good a place as it possibly can be.

be. -- if all of the world's oceans adjoin.

adjoin. This is live, doing the first

first ever live dive with great hammerheads

hammerheads and a bunch of nurse sharks

sharks as well. I have to say, it's out

out of this world. But just a couple of

of kilometres from where I am now, I got

got a chance just yesterday to do a dive

dive that proves that conservation is

is worthwhile. Give nature a chance and

and it will bounce back.

This is the Sapona. It was grounded

here in a hurricane many decades ago.

ago. Ever since, it has become a living

living reef, absolutely bursting with

with life.

So beautiful.

The structure makes a perfect

habitat, places to hide from predators,

predators, and it's covered with soft

soft corals and fans.

Stingray.

All sorts of animals take up shelter

inside.

These angelfish are just stunning.

It's like swimming through the rib cage

cage of an almighty

whale lying on the bottom. It's

incredible. The sea is full of tiny microscopic

microscopic life just looking for somewhere

somewhere to fix and make home. If we

we protect our seas, then life will bounce

bounce back, if we give it the chance.

Hope can be a very powerful thing. I

think it's so important to know that there

there is a real reason for all the efforts

efforts that scientists are making for

for our seas. If we give them a chance,

chance, they will bounce back. And this

this all has to be worth fighting for.

for. My hope that while we have been here

here we have managed to win a few more

more friends for sharks. They really need

need them. And it's been an experience

experience I will truly never forget,

forget, watching these dark silhouettes

silhouettes just circling around in the

the distance. I really hope it's an experience

experience the next generation are going

going to be able to enjoy just as much

much as I have. We have one small male

male hammerhead just nosing its way towards

towards us right now. What a sight. They

They have been stalking these seas for

for at least 400 million years and I hope

hope they have a few million more left

left in them yet. It's been amazing to

to be here in the Bahamas. And thank you

you all very much. That's me signing out.

Our time on Heron Island is also

drawing to a close. We have been so humbled

humbled by the sheer majesty of what we

we have seen here, from the tiniest little

little corals making up the reefs to the

the thousands of sea birds soaring overhead.

overhead. It's been an incredible experience

experience from beginning to end. But

But one animal has captured our hearts

hearts and minds more than any other,

other, and that is the green sea turtle.

turtle. We have seen them foraging on

on the reefs, watch them come up to the

the sands of Heron to nest. And watching

watching precious little lives and hatchlings

hatchlings emerging from the nests and

and making it out to the big blue. Janine

Janine Ferguson has been with us all week

week and has another five precious little

little individuals. Six! To release. These

These will stay in the nest. Getting a

a helping hand if they are found in the

the hatcheries. Go ahead and release them.

them. They have no mothers to watch over

over them. They are left to their own

own devices, to the elements and predators

predators that are waiting for them and

and also the ever increasing man-made

man-made threats. But they embark on epic

epic migrations, thousands of miles, the

the gardeners of the oceans. They are

are incredibly healthy and important,

important, incredibly important for the

the health of our oceans. I hope I was

was allowed to help that there! Hopefully

Hopefully these hatchlings will spend

spend hundreds of years in the oceans.

oceans. It's our responsibility to safeguard

safeguard their future. Scientists can't

can't do it alone. This is our blue planet

planet to fiercely protect through our

our actions and making our voices heard.

heard. We hope we have inspired you to

to grab that responsibility with both

both hands. Goodbye from the barrier Reef

Reef and thank you to all the scientists

scientists who have helped us here. Back

Back over to Chris.

One last chance to take a view from

the eye in the sky up there with Larry

Larry and Matt. We don't have any live

live whales at the moment but thank you

you to them for their endeavours. Liz

Liz is absolutely right. Our oceans are

are under enormous pressure. Scientists

Scientists and conservationists are working

working very hard, but this is what they

they are working for, this sort of spectacular

spectacular wildlife. Our blue planet,

planet, wild, wondrous and worth fighting

fighting for. Here goes nothing. Look

Look at the eye. I feel just as comfortable

comfortable being in here as I would do

do with a pack of humans. You are hit

hit between the eyes with so much colour.

colour. It went right between my legs!

Here it comes. Whoa! Even the camera

is covered in snot. A live turtle. Holy

Holy moly! That is one of the most amazing

amazing wildlife experiences I've ever,

ever, ever had.

I've been thinking. In 1977, Nasa

launched to space probes, the Voyagers,

Voyagers, to study Jupiter and Saturn,

Saturn, but they knew they were going

going further out into space, so they

they put a time capsule on board, an interstellar

interstellar message in the form of a

a record. On it they put some of the whale

whale song from this very record. In 1990

1990 they turned that spaceship around

around and took a photograph of our planet,

planet, from 3.7 billion miles away. And

And this is what it looked like. A pale

pale blue dot floating in some sunbeams

sunbeams deep in space. You see, our planet

planet isn't defined by the colour of

of its polls, the yellow of the deserts,

deserts, the green of the forest. Our

Our planet is defined by the blue of the

the oceans. It's an ocean planet. And

And now those space probes are 13 billion

billion miles away out in space. And to

to date, no one or nothing has listens

listens to that whale song. Nothing and

and no one is coming to save us. All of

of this beautiful life we have on the

the planet, everything that scurries across

across the ground, everything that flies

flies through the air, everything that

that swims through the ocean, is in our

our hands. It's in our hands. And now

now we are the only ones who can make

make a difference. Who is the we and the

the our? That's me and to you.

the our? That's me and to you. That's

That's me and we. Me and we just have

have to make a difference now. The open

open University has explored a free booklet

booklet exploring our impact on the oceans,

oceans, including a tearout guide to the

the different types of plastic that can

can be recycled. You can order your free

free copy.