Original subtitles

The oceans are places of wonder.

Blue Planet II showed us the beauty

and extraordinary behaviour of marine life

whilst highlighting how fragile and threatened our seas have become.

Now, as Blue Planet Live carries out a health check

on the world's oceans, we are staying closer to home.

Our British seas are rich, varied and key to our island heritage,

but how are our lifestyles affecting them?

Whoa!

We'll meet the unsung heroes dedicated to protecting our waters

and the wildlife that relies on them.

If we don't look after nature, nobody else will.

And celebrate the scientists striving for solutions

to the challenges.

Whoa!

Plus we'll meet the crabs with a flair for style.

They're dressing up in seaweed

as a means of camouflaging themselves. Yeah.

And delve into our very own deep sea coral reefs.

This is the most important deep sea coral, I think, in the whole world

and this is just off Scotland.

So dip into our UK waters and see them like you've never

seen them before.

BOTH: Welcome to Blue Planet UK.

Hello and welcome to Blue Planet UK

and it really is blue today.

But whatever the weather, there are some amazing things

to explore in our oceans.

There certainly are and today I'm pleased to say we're back

in my old stomping ground Kent or more specifically

the picture-perfect Victorian seaside resort that's Herne Bay.

Not only is it a place steeped in history,

the marine life here is one of the best.

So while the Blue Planet Live team had been carrying out a health check

on the world's oceans, we are sticking closer to home

where there are plenty of incredible stories.

There certainly are and this is what's coming up today -

how spiny dogfish have taken a battering

because of our love for fish and chips.

Who would have thought

that underneath that lovely crispy batter could be a kind of shark?

I discover how British science may offer a lifeline

to Australia's Great Barrier Reef.

This is beautiful.

Yeah, this is South East London's coral reef.

I love science experiments!

I soak up the science as I find out

how washing our clothes can cause a plastic problem.

We're finding a lot of fibres in the marine environment

and we're finding them in marine creatures as well.

And we join the Blue Planet Live team

as they descend into the unexplored depths of Costa Rica.

You know what, Gillian?

It seems like us Brits enjoy nothing more than finding a nice spot

in the sun on the coast and tucking in to the humble fish and chips.

Well, you know, the great British tradition of fish and chips

originated in the 19th century.

But the chip originated from Belgium - les pommes frites -

and fish came from Spain - pescado frito - who'd have thought it?

Doesn't sound that British at all!

When did this simple supper land in Britain?

I've been investigating.

Fish and chips first appeared on our high streets way back

in the 1860s and fast became a firm favourite for the nation,

so much so that it was one of the few foods that wasn't rationed

during World War II.

I usually go for cod or plaice myself,

but there's always plenty of other white fish on offer,

although some varieties may not be quite what you were expecting.

Who would have thought that underneath that lovely crispy batter

could be a kind of shark?

But you wouldn't have seen shark advertised on any chippy menus.

The industry has been using different names for decades to make

the fish in the dish more palatable for the public.

Rock salmon, rock, huss, rigg, flake -

these are all traditional names for shark in the UK.

Dr Andrew Griffiths of Exeter University has been researching

the use of shark products in the UK.

Andrew and his team have trawled fish and chip shops

up and down the nation

and brought fish suppers back to the lab for DNA testing.

We've analysed around about 89 fish and chip samples

and what we discovered is that over 90% of the samples that we analysed

were actually identified as spiny dogfish.

Spiny dogfish were once one of the world's most abundant shark,

but our taste for it has led to numbers being decimated.

Now endangered in the northeast Atlantic,

the EU has banned targeted fishing since 2010.

But the UK waters are still no safe haven.

Spiny dogfish have a low reproductive rate,

meaning their numbers are slow to increase.

Like many fish, they shoal together for protection,

but this behaviour is the species' downfall because when they get

caught accidentally, it's in devastating numbers.

However, there are people trying to help.

I'm joining the team from SharkStuff,

who are attempting to tag spiny dogfish, headed by Georgia French.

They're there somewhere, but you've got to land over the shoal

get on top of them... Yeah. ..and find them. Exactly.

It's hoped that by tagging the spiny dogfish

they will be able to identify their favourite marine habitats,

in the hope of making them protected sites

to safeguard the species in the future.

The team will be using specialised equipment to assess the size

of specimens in the water.

The stereo...ster... Oh, I'll be honest, I can't pronounce its name.

Using the stereo photogrammetry equipment,

we're getting measurements of sharks in the water with big sharks.

One of the worst things you can do is take them out of the water,

but it's important that you do know how big they are, so we wanted

to come up with a method where you could do that in the water.

We're getting bites.

Not spiny dogfish, but another type of shark -

spotted catfish, to be precise -

and they're small enough to land safely

and take manual measurements from, which will help judge

the accuracy of the equipment.

Perfect.

Bye, bubs.

That's actually quite a cool defence mechanism

where they curl up like that.

In South Africa,

they've got species they call shy sharks because they're supposed

to hide, like, under their tail, they curl up.

As well as small spotted catfish,

the equipment is also picking up spotted ray - a close relative

of the shark and a congo eel, even a dolphin.

No spiny dogfish yet, but it's fishing, isn't it?

There's no guarantees.

One man who knows the challenges of sea fishing better than most

is Paul Burridge.

He's an angler, not a scientist, but he's more than happy

to offer his expertise to the cause.

Yeah, there's something on there.

Little 'un.

Got a nipper.

About five years ago, I started fishing large sharks

and found it interesting that the amount of information

to be gained from the scientific community as well as fishermen

being out here on the boat.

It's all worked hand in hand.

Well, unfortunately, it looks like

we're going to go back without a spiny dogfish today,

but are you surprised?

Catching any fish on cue is always a bit of a red herring really -

it's quite hard work, but there's not a lot of them around.

They are under threat and when there's not many of them,

it's a needle in a haystack.

What I really want to ask you about on this is how important

you feel, from a fisherman's side of things,

the stuff that SharkStuff are doing?

I love their ethos. You know, it's education.

And most anglers, especially big fish anglers,

don't want to harm their catch.

And if we can show the data to say - "This is a better way of doing it,

"this is how we suggest things are done" - it's important.

We haven't been lucky on this expedition, but organisations

like SharkStuff are providing hope for the spiny dogfish,

and scientists like Andrew want to see changes in legislation.

It'd be much more useful to have clearer labelling

which becomes much more tied to a very small number of species

or a single species, which would allow the consumer to know exactly

what they're buying.

If we embrace adaptations like these,

we can make informed decisions and carry on enjoying

our fish and chip suppers without harming our sharks.

So how can we enjoy a 150-year-old British tradition

without harming our fish stocks?

Well, the Marine Conservation Society have a Good Fish Guide

where you can see which fish species

are the most sustainable - the green rated -

and the least sustainable - the red rated.

There's loads more information on the website.

Very often, it's the scale of the fishing that's the issue,

and there's a lot of smaller companies

that just aren't finding it viable

to compete against the bigger outfits,

but there's one lone fisherman in Devon

that's trying to keep alive the tradition.

For centuries, the seas around Britain have provided a livelihood

for coastal communities.

Hope Cove is one of these

historically vibrant fishing villages.

In the 1930s, there were more than 30 men fishing from here.

But times have changed.

Centuries-old traditions and the heritage of a Devon fishing village

are on the brink of being lost forever.

Over the years, one by one,

the fishermen have left and now only one man remains.

My name is David Morgan.

I'm the last full-time fisherman living in Hope Cove.

If you're in fishing, you have to work every day

that presents an opportunity for you to go fishing.

I mean, our day typically starts

at four or five o'clock in the morning

and if you're not prepared to do that,

then don't entertain the idea of going fishing.

We normally arrive at the first fleet of the pots,

any time between half past five and six o'clock in the morning

and we would haul maybe 500-600 pots continuously

until about half past two, three o'clock in the afternoon.

In the winter, the weather on average might affect us

to the extent where we don't go to sea for perhaps two or three weeks.

The long-term decline is due largely to the fact

that it's no longer possible to earn

a decent living from small-scale fishing.

Over the last 10 or 15 years, the value of crab, in real terms,

has gone down considerably.

The crew don't live in Hope Cove.

I would go so far as to say that it's impossible to find

any crew in Hope Cove and that's been the case for...

..many, many years.

The resident local population is just getting smaller and smaller

and smaller, to the extent now where, in the winter,

you've barely got a community of people here at all.

It's very interesting that when we were young lads,

there were many of us that couldn't wait to jump aboard

a fishing boat and find out about fishing,

but I don't see that happening at all any more.

I cannot see the fishing industry in Hope Cove ever returning

to anything like it was 50, 60 years ago.

There's nothing to say

that small-scale fisheries shouldn't succeed...

..but you've got to be very efficient at what you do.

It's very difficult to compete with the larger players in the market.

I don't see too many coming into the industry at all.

It's a poignant story that young film-maker Nick Adams captures

perfectly and it's one that's representative

of many of our fishing villages,

but there are some marine communities that are bouncing back,

so I went to go and find out more.

I've come to Weymouth to meet Charlotte Bolton.

She's part of a national drive to survey our seas

and has a passion for spectacular shellfish - the spiny lobster.

What on Earth is a spiny lobster?

It's like a lobster. But spiny! It has spines... But spiny!

All right, OK! And it lacks the big pincers and it has stripy antenna...

OK, right. ..so it tends to work in the reef.

And they've had a pretty rough time of it

in the past, haven't they? Oh, yes.

Spiny lobsters were effectively extinct in this country.

Basically they were fished out in the '70s and '80s

and we just didn't see them at all.

So that was a combination

of commercial fishing pressures and also divers.

Divers have to take their share of the blame here because they were

also responsible for collecting them and we simply didn't see them.

So it's really nothing to do with it being predated on

or anything to do with the environment,

but it was purely overfishing. It's us.

It's us - the apex predator is to blame again, unfortunately, yes.

And I think... I mean, now they're incredibly valuable

because there are so few of them, but we are seeing them coming back

and last year we saw them here in Dorset which was... It was amazing.

As a local diver, it's really exciting to know that they are back

in our local waters.

So what on Earth has brought around all this change for them?

If we're honest, we don't really know.

It might be one of these big planetary,

you know, sort of ocean systems.

The Atlantic Decadal Oscillation has been mentioned.

Who knows? Is it the warming seas?

We don't really know. And I suppose that's one of the things, isn't it?

There's so much going on with our oceans at the moment, man-driven

and otherwise, that it's hard to be able to put your finger

on why things might be changing.

Yes, and it's so complicated out there, you think...

You know, one little thing changes and then that knock-on effect -

this whole web of life we just don't know

and that's what for me makes it really exciting.

But whatever that change is, to have spiny lobster back on the shores

of Britain is fantastic, isn't it? Yes, it is, it is.

As a diver, I love them.

You can hear me finding them underwater because I get

all high pitched and I scream.

They are just...they are really exciting to find.

I don't think I'd ever get bored of it.

It's not all doom and gloom.

Some of it is, but there are plenty of good news stories out there,

which is really exciting.

You know, I love a story like that

and look at the passion Charlotte's got.

It is amazing, but I have an even bigger news story for you.

Steve, listen to this.

RAPID PULSING

Well, that's a bit different, isn't it?

What am I listening to there?

That is the very first minke whale

to have been recorded off the east coast of Scotland.

No way! How cool's that?

It is very.

The minke whale is one of the largest marine species

that regularly visits the Scottish coast, but it's secretive

and unpredictable which means much of its behaviour remains a mystery.

They can grow up to eight or even ten metres in length,

but are hard to track because of their behaviour.

Unlike humpback whales and dolphins,

they don't display when they come to the surface.

The Scottish Association for Marine Science and Marine Scotland Science

are thrilled to have captured that audio and it is the beginning

of hopefully learning more about these really mysterious animals.

And to be finding out that kind of thing

is really ground-breaking, isn't it?

Now before Chris Packham headed off to Mexico for Blue Planet Live,

he caught up with a biologist that has dedicated his career

to looking at some of the wildlife that lives on our British coasts.

Today I've come to meet a man called Paul Naylor and I like him.

He applies classic naturalist values,

enhanced skills in observation,

only he does it in the marine environment

and another thing I like is that he's content to work

with common species,

but he wants to know not just the species but individuals

and learn about their personalities.

Paul, what is it that lured you in there in the first place?

When the conditions are right and you can get in there and see

the animals that live in there, you just find amazing characters.

Hold on. We've got some perfectly good animals on land.

Yeah, but we see them all the time.

The ones in the sea are less familiar to us.

And one of those animals you've got to know is the tompot blenny

and this is a familiar species to anyone who's had their toe

in a rocky...rock pools and just offshore, isn't it?

Yeah, it's a very close relative of the common blenny or shanny,

which is that small greeny-brown fish

that people know in rock pools so well.

What's so... I mean, I think apart from them looking...

A very sort of early '70s glam rock fish, isn't it? Yeah.

Yeah, they look great

and then from a study point of view, what's so brilliant

about them is that they've these individual skin markings

and you can recognise them,

so you can follow an individual.

And this is a rogue's gallery

on one particular reef that we study.

These are your blenny friends... Yeah.

..that you've got to know as individual animals

and that gives you a lot more empowerment

to study them. Absolutely.

For a start, you can find out how long a male -

cos they're territorial, the males -

how long they keep territories. Go on. Tell me.

I would imagine a fish like this, two or three years seasonally.

Certainly up to five years... Five!

..five years and they'll keep the same territory. OK.

I know you've got some footage here

that you've shot of some of your blennies.

Let's have a look at this. What's going on?

Well, what's happening here is -

this is a female and she's laying eggs

and, behind, is one of the territorial males

and appearing is what we thought was another female,

but when we looked very close up later, we found that you could

just see the glands underneath it that make it a male.

But this male has snuck in presumably to try and fertilise

some of the female's eggs... Exactly.

..which is a strategy that we see in all sorts of other animals. Exactly.

But never before in the tompot blenny

before these sets of observations. And this is not a one-off.

You've seen this repeatedly. Absolutely.

And just there, he seems to have sussed it out and off he chases him.

Do you know what's striking about this is that just out there,

literally a few metres off the beach,

this new behaviour's now only being uncovered.

Exactly. What else have we got?

Another animal is the spiny spider crab.

Now all round our coasts...

This was filmed near Torquay and groups of them come together

and they go through what's called the pubertal molt, where they emerge

from their old armour as adults.

But what we didn't realise was that when they got this new armour,

they need to camouflage it again

and it's quite an intricate process.

They rub each piece of seaweed on the spines on their backs

until it sticks. So they're dressing up in seaweed

as a means of camouflaging themselves? Yes.

Maybe they've evolved the spines specifically to make it possible

to attach the seaweed. I think so, because in between the big spines,

there are these tiny curved hooks which, I think, is what the seaweed

attaches to and those hooks look just like Velcro,

the hooks on Velcro, so the spider crab invented Velcro.

What about that?

But, Paul, you don't have to be a diver to access marine life.

I mean, rock pools are full of similar species, aren't they?

Absolutely, yes.

Look into any rock pool and you can see animals

going about their lives.

And if you move things around, it is an animal's home.

I mean, it could be a blenny's territory or a shanny's territory.

Exactly. Put it back, and then safety - a little bit of a concern -

if you're going rock pooling, check the tide times, good stout footwear,

Wellingtons, that sort of stuff and if you're a young person, make sure

your parents know where you are. Absolutely. That's the key thing.

But, look, I have to say thank you very much.

It's been an absolute eye-opener. Just out there.

I've been looking at badgers and birds -

they don't dress themselves up in weed.

Amazing, absolutely amazing.

And you can see Chris and the team on Blue Planet Live tonight

when they take another look to see

how healthy the world's oceans really are.

And the health of the oceans or not, a lot of it is down to us

and although we're very aware

of the problems with single-use plastics,

who knew the clothes you wear can make such an impact?

The UK puts on a staggering seven billion washes a year,

so, with that in mind, anything that indicates

they're causing plastic pollution is a big deal.

I'm visiting a lab

at the International Marine Litter Research Unit in Plymouth

where Richard Thompson and PhD student Imogen Napper

have been researching how washing our clothes

can end up with synthetics in our seas.

Wow! You know, when you said "lab",

this isn't quite what I was expecting.

This looks more like a launderette.

It feels a bit like that sometimes, but, actually, it is a lab.

What we're trying to do here is quantify how many fibres

are coming off everyday items of clothing when you wash them.

A lot of people don't know that our clothes are made out of plastic

and this can be polyester, acrylic or natural synthetic blends

and when it's swishing and swirling around in the washing machine,

tiny fibres can come off and go down the waste water

and potentially into our oceans.

We know that we're finding a lot of fibres

in the marine environment - we're finding them in the deep sea,

we're finding them in Arctic sea ice

and we're finding them in marine creatures as well.

To find out what kind of fibres are making their way into our oceans,

we're going to run a test on three different fabrics.

So we've got 100% acrylic jumper, 100% polyester jumper

and then a blend of polyester and cotton.

Different colours means different fibres

and you just use that all the time? Yeah. See, there was me

just thinking you're separating your lights and darks. Yeah.

I love science experiments.

Never been so excited about washing.

Each item gets washed on an identical cycle

with the same detergent at the same temperature.

MUSIC: Where's Me Jumper? by The Sultans Of Ping FC

The water from the outlet pipes is filtered to collect any fibres

that would have gone down the drain and whatever is found is dried

in a petri dish.

Each sample has come from just one item of clothing after a single wash

and the next step is to take a closer look under the microscope.

OK, so first one I can see is blue

and that was the hoodie, wasn't it? Yep.

This is the blue hoodie and this was polyester-cotton blend.

This is all of the fluff

that we extracted from that one hoodie in one wash.

That is unreal, isn't it?

Because normally I'd look at that as fluff... Mmm.

..but I don't think about what the fluff is made up of. Yeah.

So this is plastic fluff,

well, polyester and cotton.

Some past research that we did showed that for a typical wash,

on average, about 130,000 fibres can come off

a polyester-cotton blend wash.

And how many washes did you get this average from?

I did over 200 hours of washes. Oh, my word!

So you really do know your blue hoodies

and the fluff that comes off it. I know this very well. OK. All right.

So, moving on, what else have we got?

The next one that we had was the fluffy black jumper

and this was made out of polyester,

different material - completely plastic this time.

It's a big tangled mess. That looks so different.

For a typical wash, up to 500,000 fibres could come off in one wash,

so three times more than the polyester-cotton blend.

Wow! All right. And we've still got another one yet. Number three.

So the next one was the beige jumper. That was made of...?

Acrylic. Hardest to see, cos it's beige.

But in our past research, we showed up to 700,000 fibres could come off

a typical clothes wash, so the most by quite a mile.

And that is all plastic. Yep.

Oh, my word!

These fibres could make their way through the sewage treatment works

and into our oceans, making it a big plastic soup.

So it really is a one way street, isn't it?

Once the plastics are in there,

it's very hard to get such small plastics out again.

So what's the answer, then? I'll just stop wearing acrylic, I guess.

Well, it's really not that easy.

Even though in our research

we've shown that acrylic shed the most fibres,

it can depend how the clothes are made, how they're woven,

so we need to look right down to the beginning of the manufacturing stage

so we can stop them shedding fibres when we're washing them.

The devil really is in the detail with this, isn't it?

At every stage of the clothes being manufactured... Yeah.

..to the way that they're washed. It's very complex.

When it comes to shed-ability, we can say that mixed fabric is bad -

the polyester three times worse

and the acrylic, by a country mile,

is bottom of the tops.

And these are the culprits here -

the microfibres, the plastic fibres that come out the clothes

and there's no real solution to it yet,

but it's all being looked into and one option is to put together

a textile that doesn't give off microfibres in the first place

and the other is to find a way to capture the microfibres

before they make their way to the ocean.

And this is a prototype to do just that.

It's a washing machine filter.

The idea being that every single washing machine would be installed

with one of these to capture all those microfibres

as micro plastic pollution entering the environment.

And it wouldn't just benefit the large marine mammals,

it would benefit the tiny things as well

cos even plankton is being affected by this micro plastic pollution.

And plankton is the cornerstone for every ocean ecosystem,

as The One Show's Mike Dilger found out.

If someone sent you the greatest migration on Earth,

what would you think of -

wildebeest crossing the Serengeti plains,

caribou crossing the Arctic tundra?

Nice guesses but, no, because it's plankton

and this amazing journey happens just off our shores.

The animals that take part in this huge migration underpin

all marine life in the British Isles,

but, for the most part, you'll probably have never even seen them.

I've come to the west coast of Scotland and the beautiful island

of Mull to take a closer look at plankton -

these tiny but incredibly important organisms.

During the summer months, the seas off the British Isles transform,

filling up with swirling patterns

covering hundreds of square kilometres,

which can even be seen from space.

These patterns are, in fact,

blooms of tiny plants called phytoplankton -

most no bigger than a pinhead.

These tiny plants are so numerous.

they produce over half the oxygen we breathe,

they even give the sea its smell and, most importantly,

they're the food of the creatures I've come to investigate today.

I'm on a quest to find zooplankton,

some of the weirdest animals on the planet.

They're so small that if we want to find them, we need to look out

for the predators that feed on them.

Zooplankton make an incredible journey each day,

moving between the surface waters where they feed

and the dark depths where they're safe from predators.

Some of these tiny individuals

travel to depths of half a kilometre.

This monumental feat by so many minuscule animals makes them part

of the biggest migration on the planet.

Here off the Hebrides, the upwelling waters, which are rich in nutrients,

create a plankton hot spot.

And in these waters off the coast of Tiree,

it isn't long before we find what we're looking for.

This is fabulous behaviour.

You've got sand eel that feed on plankton,

being pushed to the surface by bigger fish

and then we've got the birds piling in from the top.

I'm watching gannets diving from 25 to 30 metres up and slamming

into the water and they're feeding on big shoals of fish

and where there are fish, there are going to be huge plankton blooms

and that's what we want to see.

Zooplankton may be amongst the most numerous animals on Earth,

but catching them isn't easy,

so we've brought plankton Professor David Pond to help us.

With his specialist net system,

we soon catch some of these marathon migrators while they're up

at the surface feeding and head back to the lab.

David, this is a whole new world.

So talk me through this very distinctive creature

with what looks like a fantail and red in its body.

It's a really large copepod.

It's about seven millimetres long

and it's kind of the lion of the sea.

It's carnivorous and it basically eats all the other chaps.

There's one as well that's incredibly distinctive

with long antennae that also has red running through its body

and this seems almost the most numerous.

It's found across the North Atlantic, up into the Arctic.

It's really important as a source of fish food

for commercially important species and you can see along here,

running along the length of its body,

you can see an oil sac like lipid - it's fat basically.

Fish like herring and mackerel feed on these copepods in huge numbers

and then transfers that lipid, that oil, into its tissues.

And that's the omega-3 that we need to eat for our own diet.

Absolutely.

It's incredible to think that the world's marine life

is so reliant on such tiny animals,

so the next time you're sitting down to a fish supper,

remember - it's all down to the plankton.

Microscopic organisms are crucial to healthy ocean habitats

like coral reefs.

Coral are affected by climate change, however,

because as sea temperatures rise, it causes them to go white.

It's called bleaching and can lead to the coral dying.

It's a really sobering sight but I went to London to meet

a scientist who thinks he may have come up with a solution.

Jamie Craggs of the Horniman Museum is leading the fight

to save the world's coral,

and this little piece of Australia's Great Barrier Reef holds the key.

Hello. Nice to meet you. Nice to meet you.

Oh, my goodness. This is beautiful.

Yeah, this is southeast London's coral reef. That's incredible.

So this is where all the action happens? Absolutely, yeah.

Reproduction is obviously the process

that a species and population continues,

so studying reproduction gives us that fundamental knowledge,

but then getting them to reproduce is very difficult.

So our work is focusing on triggering them to reproduce

and understanding what happens in the wild,

replicating that in aquariums.

Some of these individual corals are special,

because they're genetically resistant to coral bleaching.

It's hoped their offspring can help save the world's dying reefs.

But breeding coral is easier said than done.

These corals only spawn over just a couple of nights a year,

so there's a very small window of time to get the material you need

for your experiments.

Coral spawning is triggered by a precise combination of day length,

water temperature and the phase of the moon.

To get coral to breed in the lab,

all these conditions must be mirrored exactly.

So that's the sun. How do you replicate a moon?

We have four LED lights and then

a ping-pong ball's been cut in half to act as a diffuser.

And really importantly, three bits of sticky tape have been put

over the top to make sure it's

exactly the same amount of light as a full moon.

In the natural world, other creatures live amongst the coral,

like sea urchins.

These resilient little animals graze on algae

which can kill the coral if left unchecked.

So these are going to be like room mates or tank mates, I should say,

for the corals. Yeah, so we've got four different age groups here

of urchins and they each have their own use.

So when they're nice and small, they're great with the baby corals.

As they get older, we then move them in to control the algae

in with our adult corals.

If the young corals are to feel at home,

they need the sea urchins there too.

And Jamie has a breeding programme to maintain his supply

of juvenile urchins.

It's all kicking off in here, isn't it? Absolutely. Oh, my goodness.

We've got five males spawning and then a female over here

is producing eggs. That's a huge, massive egg. That's incredible.

The Horniman Museum was the first institution in the world

to successfully breed coral in captivity

and they filmed the magical moment it all began.

Once the coral starts to spawn, the eggs and the sperm are collected

so that Jamie can maximise the chances of fertilisation.

While we can get the corals to spawn in a very planned way now,

we can rear potentially hundreds of thousands of embryos.

The next frontier and the next challenge for us is to get those

hundreds of thousands of larvae to settle, grow into baby corals

and then have hundreds of thousands of corals.

As the coral grows, it's transplanted into tanks.

Here, the team has come up with a novel way

of monitoring their health.

I'm guessing these are here for a reason.

Yeah, if we use the light, the blue light in combination with goggles,

it allows us to highlight the fluorescence

that are inside the corals.

That is beautiful.

They glow.

Why would coral need to fluoresce?

There's a lot of debate about it.

One thought is the proteins, the fluorescent proteins, act

as a sunscreen, a bit like suntan lotion, for the corals

and it protects them against the harsh UV rays of the sun.

In successfully spawning, breeding and growing coral,

Jamie has made amazing progress.

The next hurdle is to grow thousands of warm-water-tolerant coral

and take them back into the oceans

to help fortify our reefs against climate change.

That was a superb bit of research

and hopefully will make a real difference.

Tomorrow, we're going to be looking at British coral reefs,

only in much deeper water.

And to help understand the challenges, our cameras follow

the Blue Planet Live team as they drill down

deep off the coast of Costa Rica.

So it's about five o'clock in the morning.

We've been up since about four, four-thirty.

We're about 50 miles off

the Pacific coast of Costa Rica.

As you can probably see,

we're just about to rendezvous with the RV Atlantis.

The Atlantis is a scientific research vessel

carrying some very special cargo.

We are filming with Erik Cordes, who's the leader of this expedition

to a series of sea mounts that have never been explored before.

What they're going to find - who knows?

These underwater mountains rise from the ocean's floor

but their peaks never break the water's surface.

To embark on the expedition, Erik Cordes will be using

a submarine called Alvin.

So, Alvin, by the time we get on board, is already in operation.

They're doing their dive checks

and making sure it's completely safe, it's operational.

So that's all going on as we turn up,

so as soon as we start the day,

as soon as we get on board, it's go.

So they're just about to go on a dive.

You can see here at the front of Alvin,

you've got all the area

where essentially these robotic arms can pick up samples.

We've got soil samples here.

You've got places where they can pick up specimens and keep them

until they're on the way up.

Just as a bit of filming equipment, it's pretty incredible.

You have pan and tilt cameras up the top there.

It's equipped with 4K camera.

It's got cameras on the arms here.

It can actually grab cameras with these arms and then place them

on the sea floor and then be able to move around them.

It's absolutely incredible.

All of them of course have got their own pressure...specialised casing,

so they can deal with the pressures

at thousands and thousands of metres deep.

So we haven't be able to take our own cameras into Alvin,

so we are using the cameras that they've got.

You know, we've been having to test that out as we go.

Usually you do that back at base -

you'd do that before you'd arrive, but it's still just a challenge,

just to try and work that out and make sure that we get it right,

because Erik is only going down once.

So if it goes wrong...

..then we could have a problem.

With final checks complete, Alvin is ready to start its mission

exploring the sea mounts.

So Erik's just left now.

He's going to be down there for about eight hours.

I just can't wait to see what he comes back with.

It's going to be amazing.

Watch Blue Planet Live

to find out the results of Alvin's deep sea dive.

That's it for today.

Don't forget Blue Planet Live on BBC One tonight.

We're going to be back tomorrow, same time, but from Scotland

for our final Blue Planet UK. See you then.

In our final programme, I delve into the deep of our British oceans.

We're actually looking at an area 1.5km deep.

We learn about one of the most secretive species in UK waters.

I remember the very first time I saw a seahorse in the wild.

Absolutely amazing.

Chris reveals why he has a passion for our coastline.

I feel a closeness to the sea because of the birds

that are an intrinsic part of that environment.

And there's a sight to behold as herring return to Scotland's coast.

There's a great wall of herring going round and round me.

It's fantastic.