Original subtitles

The Great Barrier Reef.

It's home to an extraordinarily diverse community

of animals and plants.

'Here, unknown species are still being found

'and astonishing things discovered about creatures we thought we knew.

'In this series, our research vessel, the Alucia,

'will allow us to explore and understand the reef as never before.

'This marine paradise may be best known

'for its spectacular coral reefs...

'..but it also has 300 sand islands.'

600 continental islands.

Miles of lush forest.

And deep ocean channels.

Each of these habitats attracts a very different set of visitors.

When I first came here almost 60 years ago,

we knew very little about these communities.

But today, new tracking systems are allowing us

to follow the lives of these creatures in new ways.

From the ocean's great predators...

..to a mysterious whale that seeks out human contact.

I'll discover their surprising reasons for visiting

and reveal why the reef is so important for their survival.

Last time, we looked at the rich community of animals

that lives among the coral,

but the reef also receives visitors.

Some travel for thousands of miles in order to get here

and stay for only a few weeks.

Others linger on the fringes and come in every day.

Each has its own particular reason for doing so.

The Great Barrier Reef consists of 3,000 individual coral reefs.

It stretches for 1,400 miles along Australia's northeast coast.

And every year, it attracts over a million migrating animals.

We're beginning our exploration in the north,

on the outskirts of this vast wilderness.

Our research vessel, the Alucia,

has brought us out here to Osprey Reef.

90 miles, 150 kilometres out in the Coral Sea

from the edge of the Great Barrier.

Isolated though it is, it nonetheless plays a crucial part

in the lives of many of the inhabitants of the Barrier Reef.

What makes Osprey so interesting

is that it lies in the path of the south equatorial current.

This is a moving highway

that sweeps a host of different visitors towards the great reef.

We are here to discover

why this remote outpost is so important to them.

To do that, we're going to use a very special piece of technology,

the Alucia's Triton submarine.

It's the first submersible of its kind ever to dive in these waters.

Huh! It does look as though water's gurgling up here,

but in fact, my feet aren't wet.

S-O, S-O, this is Nadir. Am I clear to vent? Over.

'Copy Nadir. So you are clear to vent, clear to vent.

'Have a good dive, guys.'

Roger. Venting now.

There we are!

'The sub not only gives us stunning 360-degree views,

'it allows us to dive to depths where no unprotected human has ever been.'

For this dive, we are only going down to about 35 metres,

just over 100 feet,

where much of the wildlife we're hoping to film will be feeding.

Marine geologists have recently gathered sufficient data

for us to create an accurate three-dimensional picture

of Osprey Reef for the very first time.

It is, in fact, a huge mountain hidden beneath the waves

and rising steeply from the seafloor 2,400 metres below.

The top of this vast seamount creates a shallow lagoon

that supports a flourishing community of corals.

This wall of rock ahead of me is the flank of Osprey Reef.

When cold, deep, nutrient-rich currents from the ocean

come in and strike it, they defect it upwards.

And that creates an oasis for living creatures of all kinds.

Many creatures live here throughout the year.

And the boss of them all is one kind, sharks.

There's one! Close up.

Whatever else you say about sharks, they are so beautiful in the water.

Resident predators mean one thing -

a plentiful supply of food.

For creatures travelling vast distances to get to the reef,

that makes Osprey a very desirable waypoint on their journey.

Seamounts are stopping-off points for visitors.

They come from far and wide.

From tiger sharks to turtles.

And they come to refuel and also, it seems, recalibrate.

It appears that this is a signpost

and a checkpoint on the way to the reef.

Visitors arrive year round.

Among them are hammerheads.

Like all sharks, they have tiny sensors on their nose

which can pick up signals from the earth's magnetic field.

And that helps them navigate through the blue infinity of the open ocean.

There are tiger sharks here, too.

They come to the reef to feed.

And they seem to know exactly where they're going.

The proportion of their brain dedicated to smell

is the largest of any shark.

Their two nostrils work independently,

allowing them to smell in stereo and track prey over huge distances.

From Osprey, some tiger sharks

travel to a very specific destination on the reef.

230 miles north of Osprey lies Raine Island.

Every summer, the tiger sharks arrive without fail.

They're here to take advantage of a major event on the reef -

the arrival of the female green turtles.

The tiger sharks aren't here to kill, they've come to scavenge on the dead.

The unlucky turtles who have not survived

their exhausting immigration.

This is why the tiger shark has earned the unflattering title...

..Dustbin of the Sea.

They prefer the easy life of the scavenger,

so the majority of green turtles have little to fear from these predators.

In the summer months, the turtles arrive in thousands.

They have come from as far as New Guinea, Vanuatu

and New Caledonia to the east,

as well as from the Torres Straits and beyond to the west.

Some have travelled an impressive 1,500 miles

to reach this particular beach.

It measures only a few hundred metres across,

a tiny speck in a vast ocean.

But Raine Island plays a major role in their lives.

70% of the Barrier Reef's breeding green turtles come here to lay.

It's one of the most important nesting sites in the world.

I first visited Raine for a television series

called Zoo Quest back in 1957.

At the time, Raine was little known and rarely visited.

It was then I met my first green turtle hatchling.

Back then, we had no idea

just how extraordinary a story these turtles had to tell.

We now know that if they survive,

they'll spend the next 40 years of their lives at sea.

Only then do they return to Raine to breed.

And astonishingly, they return to exactly the same beach

where they themselves hatched.

How they find their way back after decades at sea

is one of the mysteries that surround this species.

But new research is suggesting that, just like the sharks,

they navigate using the earth's magnetic field.

They weigh up to 130 kilos,

so hauling themselves up the beach is a gruelling task.

But it's expected that 30,000 of them

will come ashore to lay their eggs this year.

With space in short supply, it's every female for herself.

Once they've dug a hole, laying can begin.

Each egg is roughly the size of a Ping-Pong ball.

A female may lay up to 120 of them at a time

and she's able to do this six times in a single breeding season.

Once the eggs are laid, she buries them.

For the next 60 days, the sand will conceal them from predators

and protect them from the blistering sun.

Keeping a very close eye on the turtles' progress

is Dr Andy Dunstan of the Great Barrier Reef Marine Park Authority.

Raine Island is the biggest green turtle rookery in the world.

So it's incredibly important

with the state of green turtles at the moment.

Because of this, Raine is the most protected island on the reef.

Only a handful of biologists are allowed to land here

and Andy and his team have done so for very good reason.

A huge number of turtles are certainly coming ashore

to lay their eggs on the island,

but the team's observations have revealed a worrying trend.

The number of young hatchlings surviving incubation in the sand

has dropped to just 20%.

It's a serious cause for concern.

The hatchlings we're seeing coming out

are nowhere near the numbers that they should be.

The nests, when we dig them up,

have got really low levels of successful eggs hatching.

And that is happening because of the very substance

that makes this island so suitable for nest-building in the first place.

Raine Island's a sand island. They move.

But specifically for the green turtles here,

the nesting area has become lower, so what we're seeing now

that we never saw 30 years ago is inundation of tidal waters.

This means that at high tide, the island is being flooded from below

and the developing turtle eggs are being drowned.

75% of the beach-nesting area is not suitable.

Because turtles take a long time to mature,

we expect to see a crash in those adult turtle numbers in the future.

If we do something about hatchling success and nesting success now,

we should see that recover again.

Last year, Andy and his team made an ambitious plan.

In a trial sector, they have raised the turtles nesting area

by one and a half metres.

They hope this will keep the developing eggs

clear of the tidal waters and out of harm's way.

Two long months after the egg laying began,

the team returns to see if their plan is working.

Under the cover of darkness,

the first of the evening's hatchlings start to emerge.

They started to push their way up

through the sand about two days earlier.

Now comes the moment that Andy and his team have been waiting for.

A shallow trench helps to delay the new arrivals temporarily

and allow the team to count them.

So far, the signs are very encouraging.

And as the night wears on, it gets better and better.

This is looking great. We're getting much better nesting success,

much better hatching success,

the turtles are nesting right across the whole area

and not disturbing each other so much.

And those clutches which are underneath the sand

are hatching much more successfully.

It's confirmation that Andy and his team have found the right way

to restore this vital breeding area.

But for the young hatchlings, the trials of life have only just begun.

Each new arrival will have to make a perilous dash to reach the ocean.

Now they're on their own.

Andy and his team must not interfere at this stage.

Inevitably, the tiny, defenceless hatchlings

attract scores of predators.

SQUAWKING

Terns and herons patrol the beach.

And in the shallows, reef sharks lie in wait.

Great numbers are lost,

but enough will make it to the ocean to ensure the species' survival.

As the young turtles leave the reef,

they get a helping hand from the ocean currents.

Swept out into the open ocean and there, they face new hazards.

If they survive, they will eventually return

to the very same beaches where they hatched.

Remote islands like Raine are hugely important

to both turtles and birds

that come to the reef to lay their eggs.

There are 900 isolated islands on the Great Barrier from which to choose

and there's a habitat to suit every visitor.

Turtles need sandy beaches

and many birds need trees.

'The Alucia is taking us to one of these wooded islands

'near the southern end of the Great Barrier.'

Almost 1,000 miles south of Raine is Heron Island.

And every year, it attracts

thousands of birds seeking somewhere safe to nest.

The island is surrounded by fragile coral reef.

So to reach the shore, I'm leaving the Alucia anchored in deeper water.

FAINT BIRDSONG

The warm waters of the Barrier Reef are full of fish.

Full of food, as far as birds are concerned.

There are immense numbers of seabirds throughout the year on the reef.

But the moment comes in the year when, in fact, a bird has to lay.

And to do that, it has to go onto land.

And the number of sites where they can build a nest are very limited.

So they will put up with a great deal of crowding

and even with intruders, like myself, without deserting their nest.

Hello.

'Noddies are very protective parents.

'Very little deters them from their chick-rearing duties.'

Over one-and-a-half million birds

come to the Great Barrier's islands every year to breed.

To see one of the most intriguing, you'll have to wait until after dark.

WAILING

'The first indication that this secretive character has arrived

'is its rather unusual song.'

WAILING

The old sailors used to call it the ghost bird

because of its extraordinary call.

More properly known as the wedge-tailed shearwater.

WAILING

'The birds' haunting calls guide me to their breeding grounds.'

WAILING

These are true seafaring birds. Out at sea when they're feeding,

they are very expert at flying just above the surface,

or indeed swimming on the surface, catching their fish.

But when they come into land, well,

they have to come in in the dark, for a start.

And their landing is sometimes not very expert.

Night-vision cameras probably give us

better pictures of their landing ground than they seem to have.

Their legs with which they paddle over the surface of the sea

are placed far back on their body, and that makes them clumsy walkers.

These birds have travelled

an extraordinary 4,000 miles to get here.

After spending months feeding at sea,

they've had to come to land in order to breed.

Once paired, they're devoted couples

and both male and female share the tasks of parenthood.

Even though there are trees here,

the shearwaters prefer to make their nests underground.

At the bottom of the nest hole, their three-week-old chick

is waiting for its next meal.

TWEETING

Being a shearwater parent is a demanding job.

Their young requires constant feeding.

It consumes so much food

that eventually, it'll outweigh its own parents.

But its demands compel the adults to continually fly out to sea

and come back again with more food.

And their takeoffs are often just as clumsy as their landings.

Fortunately for their nestlings,

there's no shortage of fish in the summer months.

And scientists have only just discovered why that is.

In the waters just beyond Heron Island,

there's a rich, swirling current known as the Capricorn Eddy.

As it spins clockwise, it pulls up cool waters from below,

which bring rich nutrients to the surface.

That fuels the growth of huge blooms of tiny marine creatures, plankton,

the foundation of the entire marine food web.

So this part of the reef is particularly rich with fish.

Vital food for the hungry young.

By choosing Heron Island as a nesting ground,

the birds can give their nestlings the best possible start in life.

When I first came to the Barrier Reef,

we knew very little about these seasonal visitors.

We could only speculate as to why they came here

and where they came from.

Today, new research is enabling us to understand more clearly

why, every year, particular species come to specific locations to breed.

But there are still large animals

whose movements remain something of a mystery.

Manta rays are the nomads of the reef.

They're huge creatures.

They can measure 15 feet, five metres across

and weigh almost one-and-a-half tonnes.

They come to the reef to feed on plankton,

but they also use it as a sanctuary,

where they can breed, or get a good clean.

Many make their way to the waters that surround Lady Elliot Island

on the southern end of the Great Barrier.

For the visiting manta rays, this is a paradise.

A place where these ocean giants can get a little pampering.

These are the beauty salons of the reef.

And they're often run by a pair of wrasse,

small fish with a stripe running from head to tail.

These committed cleaners

regularly tend to a host of different creatures.

They provide a vital service,

removing the dead skin and parasites from outside

and even inside their clients' bodies.

It may seem like a thankless task,

but the cleaner fish are getting a good meal out of it.

And of all their clients, the manta rays are their star customers.

When business is brisk, they patiently wait in line.

Like planes in a holding pattern,

they circle until an opportunity arrives.

When it's their turn, the manta rays surrender themselves completely.

Within seconds, a host of fish rush to their side.

Manta rays are rarely left waiting for long.

Each fish tends to a very specific part of the manta's body.

And the cleaning can last a full hour.

For the most part, the service is second to none.

But occasionally, the cleaners can get a little carried away.

A female wrasse has taken a nibble out of the manta ray's flesh.

She's broken the rules, and there's a price pay.

Her partner chases after her.

It's the cleaner fish equivalent of a stern telling off.

Scientists believe males do this to protect future business.

If the bite is a one-off, the manta ray will return.

But research has shown that if it happens too often,

the pair risks driving regular visitors away.

Fortunately, it seems her indiscretion

hasn't put their client off.

The manta is back and business has resumed.

Manta rays come here in such numbers

that the island has become the focal point for a research project.

Dr Kathy Townsend has been tracking the manta's movements

and numbers for the last seven years.

Lady Elliot Island is like the centre of the universe

for manta rays on the east coast of Australia.

We come back time and time again

because we get large aggregations of these animals.

We are doing several things with the manta rays.

First of all, we're trying to understand

how many there are potentially here.

And to do that, you need to do some sort of tagging.

This is a key part of Kathy's work in tracking these gentle ocean giants.

And the team has already attached acoustic tags

to a large number of study animals.

We have six acoustic listening stations around Lady Elliot Island.

And as an animal goes past,

within a 500-metre radius of this listening station,

it picks up the tag and we know that that animal's been past.

That has revealed that many of the mantas have travelled

hundreds of miles up the eastern coast of Australia to get here.

One of the lovely things about working with manta rays

is that they're extremely curious

and they'll seek you out to come and see what you're up to.

It's really unusual behaviour.

Most sharks and rays have no interest

in having any interaction with people whatsoever.

But for whatever reason, manta rays are highly-curious creatures

and will basically look at you eye to eye.

The manta ray's inquisitive nature works to Kathy's advantage.

It means she can get close enough to photograph them for identification.

And one of the best places to do that is at the cleaning stations.

We need to get in underneath the animal

and take a photograph from below.

Each individual has a very unique spot pattern

that stays with them from birth until they pass away.

That's very handy for us.

When Project Manta began seven years ago,

it was thought that fewer than 40 individuals came to Lady Elliot.

Today, Kathy and her team have catalogued more than 800.

I think manta ray research is quite important

because first of all, this is a very large-bodied animal

that very little information is known about.

Various places around the world,

the manta ray populations have declined dramatically,

to the point where they've now been listed as threatened

on that list for endangered species.

For the visiting mantas, the Great Barrier Reef really is a sanctuary.

Here, this ocean giant is properly protected.

While they're in these waters,

they're safe from the fisheries that threaten them elsewhere.

Manta rays aren't the only animals that find refuge here.

The Great Barrier protects its visitors in many different ways.

'That becomes clear when you look at the reef from above.

'This part of tropical Australia

'lies right in the path of regular seasonal cyclones.

'And from up here, you can see what valuable protection

'the reef can provide.'

This tangle of limestone walls

acts as a barrier against the open ocean.

Between it and the land, the waters are warm and shallow.

An ideal haven for visitors.

In the winter, many creatures come up here to escape

the freezing temperatures of the Antarctic.

Among them are humpback whales.

WHALE SONG

Weighing up to 40 tonnes,

they're the largest of the Great Barrier Reef's visitors

and they have also travelled great distances to get here.

Each year, they make an exhausting 6,000-mile-round trip

from the Antarctic and back again.

Incredibly, 20,000 of them do it.

Here, in these warm and sheltered waters,

they give birth and suckle their newborn calves.

But in fact, we still know very little

about what else they do once they get here.

Where exactly do they go during their time on the reef?

The fact that we don't know

is a reminder of just how vast this great wilderness is.

But not all whales make the task of tracking them so hard.

In fact, there's one species which does quite the opposite.

Incredibly, this whale actively seeks out the scientists

who are trying to study them.

This endearing little character is the dwarf minke whale.

And surprisingly, it was only first observed

here on the reef in the 1980s.

But since then, we've realised that they're extremely faithful visitors,

returning every year to the same location on the northern reef.

Why they do so, we still don't understand.

But research is beginning to reveal their story.

Dr Alistair Birtles knows more about

this still-mysterious species than anyone else.

So he's affectionately known as Professor Minke.

To observe the whales in detail, he has to step into their world.

The very first time I got in the water, um...

was with a degree of apprehension, great excitement.

Um...I don't think I'd ever been in the water with a whale before.

And the first thing you see is the white shoulder, um...

and then the rest of the grey animal emerges around it.

It's very special being in the water

with these animals in their own environment.

It's an extraordinary experience.

Every year, Alistair and his research team

return to spend time with the dwarf minkes.

These annual reunions are beginning to reveal more and more

about these fascinating creatures.

It seems that they spend most of their lives out in the open ocean,

leading what's thought to be a solitary existence.

But surprisingly, when they get here, on the Great Reef,

they actively seek human contact.

Behaviour like this happens nowhere else.

It is entirely the world's curiosity that brings them in.

I think we're a rather strange object.

We're a visitor into their world.

I'm sure they're wondering exactly what we are

and what we're doing, just as we're wondering what they're doing.

For Birtles, there are many familiar faces here.

And he has his own pet names for regular visitors.

Bento, I have seen every year for the last eight years.

She has a bent-over dorsal fin

from I think where she was fairly savagely mauled by a shark.

And last year's encounter was a particularly special one

because she had a calf with her.

That's the first time in eight years that we've known she had a calf.

And it was a little male and it was a very special interaction.

What Birtles and his team want to discover

is why this usually-solitary whale

suddenly becomes so extremely social when it gets here.

There are a number of clues.

We know they're not feeding. We've never seen them feed.

But we see a lot of socialising going on.

Minkes were known as the silent whale when we began working on them

and there were no recordings of dwarf minkes.

It went on for quite a while before we heard any sounds.

And then there's an extraordinary sound they make

which the researcher who labelled it

called it the Star Wars sound.

I thought it was a little more like Beethoven's Fifth

because it's got a triple beat and then a long shwang

that he thought was the lightsaber.

So it goes, da-da-da-dang.

WHALE SONG

WHALE SONG

When you hear it underwater, it kind of reverberates through your chest.

It's a very powerful sound.

WHALE SONG

The song is only produced by males

and it's thought to be related to courtship.

WHALE SONG

Curiously, two thirds of the individuals

Alistair encounters are adolescents.

One theory is that the whales are coming here to find potential mates

and learn the dos and don'ts of minke social behaviour.

Though Birtles' team has amassed

a huge amount of data over the decades,

there is clearly still much to learn.

Where, for example, do the whales go after this social gathering?

But now, a brand-new tagging programme

is shedding more light on their annual journey.

Tagging is not easy.

The diver has to get into position,

choose his mark and then discharge the tag,

all on a single breath.

There's no room for error.

After initially taking fright,

the whale comes back to the dive boat.

It seems that minkes aren't too distressed by the process.

The tracking data the team is now collecting

may reveal the piece of the puzzle that, until now, has been missing.

So for 20 years, we've been studying what the whales do

in this area of the Great Barrier Reef.

We know they're only here for a few weeks

and we had no idea where they went

when they left the Great Barrier Reef

at the end of their sojourn here.

It really is an extraordinary journey

that we now know that they make.

Spot, the young male that was the first ever minke

to have a satellite tag attached in 2013,

he travelled over 7,000 kilometres deep into the Subantarctic.

That's an extraordinary journey for what is a little whale, to make.

The tagging tells us where the whales are travelling fast

and where they're spending extra time.

There's a few places along the east coast of Australia and Bass Strait

where they may spend one, two or even three weeks of time

milling around, probably feeding.

So we may have discovered some of these feeding sites

for the dwarf minke whale along their migration path.

For Birtles, it's not just about

solving the mystery of where the whales go.

I am worried about them when they leave the reef.

The dwarf minkes are well protected

when they're in the Great Barrier Reef,

but when they leave there, they face many threats and dangers

and they have to cross major shipping channels.

There are all sorts of threats from fishing.

I mean, if commercial whaling is resumed in the Southern Ocean,

which is the objective of the research that's going on

at the moment from the Japanese, then these whales would be at risk.

It's hoped the new tagging programme may help us understand

how best to protect these whales throughout the entire year.

By venturing into their underwater world, Birtles and his team

are discovering valuable new facts about these whales.

But their research has only just begun.

The more we learn about the creatures that come here, the more we discover

just how important the Great Barrier Reef is to their survival.

The reef is immense.

Millions of visitors travel great distances to get to it.

And there, find food, shelter and an opportunity to meet a mate.

A global community of animals rely on this great wilderness.

And that makes it one of the most important

and influential habitats on the planet.

Next time, in our final programme...

..we'll investigate the dangers that now threaten the reef

and its inhabitants.

THUNDERCLAP

We'll meet the extraordinary people

who are doing everything in their power

to protect this marine paradise.

It is one of the most magnificent ecosystems on the planet.

What's really quite shocking is that we may lose it

before we truly understand it.

And we'll attempt our most ambitious dive yet.

Nobody has ever dived as deep as this before on the Great Barrier Reef.

As we search for new species and try to predict what the future holds

for the Great Barrier.

For this episode, one of our underwater teams

travelled to Lady Elliot Island in the south.

Here, the reef's majestic manta rays

are stripped of dead skin and parasites by tiny cleaner fish.

The crew's goal was to film a rare behaviour.

The moment when the cleaner fish breaks the rules

and bites a manta ray's flesh.

To film the story, the team worked closely

with marine biologist, Dr Kathy Townsend.

Manta rays will often seek out and spend time with divers,

which, of course, makes them amazing animals to be in the water with.

Manta rays may be inquisitive, but they can easily be spooked.

The challenge for cameraman, Mike Pitts,

was to make himself as unobtrusive as possible.

You are bulky and clumsy,

you've got large cameras, lights.

So what you don't want to do is to obstruct the manta ray.

The manta ray might get disturbed and it'll just swim off.

I generally keep as low as possible.

So your profile sort of matches in with the reef.

And so what you notice after a while is

the manta rays will come closer and closer and closer to you.

And I can literally... I feel them brushing over my head as they go.

While the team's objective was to film the cleaning station,

on the fourth day of the shoot,

they were treated to something truly unexpected.

We were close to the end of the dive

and we hadn't really seen anything for about 58 minutes

and then I spotted a pair.

I saw Kathy and suddenly she zoomed off and we followed.

And I could see out in the distance, there was a male above a female

and he was following her every move

as she moved through the water.

Kathy got really excited.

They were undergoing behaviour I'd never seen before.

I'd seen various types of courtship behaviour

that involves having trains,

where there's a female at the front followed by several males.

What was happening between these two was really quite unique.

The male was obviously trying to court her,

but in a very unusual way.

He was taking his front cephalic lobes

and he was actually stroking her on her back.

Obviously trying to entice her to say,

"Listen, you know, I'm the one for you".

She, on the other hand, was not quite enthusiastic

about the attention that he was bestowing upon her.

And all of sudden, she'd just fling up into the air to shake him off

and say, "No, it's not ready for that yet".

And then she would settle back down.

I knew it was something very special because,

seeing Kathy's reactions to what was going on,

she was so excited about it, she was bubbling.

You could wait a lifetime to see something like that.

Just a very rare event.

In the far north, another wildlife crew had their sights set

on filming a very special seasonal visitor.

In winter, dwarf minke whales come to the reef

for just a few short weeks.

Wildlife cameraman, Dean Miller,

has been documenting these whales for 15 years.

It's a little bit unnerving sometimes jumping in

and seeing a seven-tonne, seven-metre animal

come out from the gloom.

And you're hoping that it is going to be the whale

and not something with a few more teeth.

Every animal presents a very different challenge

when it comes to filming behaviour,

but over the years, Dean has learned the minke tricks of the trade.

It's sometimes a game of cat and mouse, in a way.

Because if you're not looking, they tend to come a lot closer.

So if I can see a whale approaching in the distance

and I know it's going to be a good approach this time,

I'll purposely hold off and turn my dome around

and actually see in the reflection of the dome the whale coming to me

and then, when I think it's probably about five to six metres away,

I'll turn around and get the best shot I've had all day.

They sneak up on you.

Over time, they build up that confidence

and they just really, really try to edge much closer

each and every time and get a good look.

I do have other tricks, as well. I'll sing through my snorkel.

HUMMING

You can be in the water for seven, eight hours a day

and you might only get two of these passes for that whole day.

And when they happen, they're just mind-blowing.

You've got this big, big animal.

I mean, it's the size of a minibus, coming to look at you.

You can get out at the end of a day and just have the biggest smile.

I've just watched the sunset from in the water.

A whale nearly touched me. It just doesn't get any better.

'While our underwater crews

'were rewarded with spectacular interactions,

'on Heron Island, I had the opportunity

'to meet one of my favourite visitors.'

The noddy.

The birds' relaxed nature and attachment to their nests

meant we could tell their story without disturbing them.

Without deserting their nest.

Hello.

But when cameraman, Mike Pitts returns

to film the hatchlings three months later,

disaster hits the island on his first night.

THUNDERCLAP

WIND GUSTS

The following morning, Mike discovers that the storm has destroyed

the very spot where I had filmed.

It was shattered. It was like a warzone.

You think of these idyllic, tropical islands

and you couldn't be further from the truth.

Are you still rolling?

You can see that many of the trees are down.

And it's brought down the chicks with them and the nests.

Eggs are smashed, chicks are dying.

And the chicks that have survived

are now on these trunks and branches

and on the ground of the forest itself,

hoping for their parent birds

to find them and bring the food they need.

But the parent birds are so confused

because so many of the trees are gone.

It's very disheartening to see it, and, er...it's a real sad sight.

I'd never seen the aftermath of such a strong storm.

But, of course, your emotions always get the better of you.

You still see survivors, just sitting on the nest,

protecting the egg or the chick.

It really is quite amazing, their resilience.

It puts the whole reef into a context whereby

you're following the rhythms of life.

We were there to record it and film it

and that's part of the Great Reef story.