Original subtitles

BARRY HUMPHRIES: As the dawn breaks across Australia,

the marsupials go to bed.

Except for the ones that don't.

Because there are exceptions to every rule

in this land of wonders.

And magic does not have rules.

It has dragons...

miniature dancers...

spiky egg layers.

But the land is only where the wild things begin.

The seas surrounding the island hold even more wonders.

Three different oceans circle Australia -

the cold Southern Ocean,

the calm sanctuary of the Pacific with its reefs and islands,

the warm Indian Ocean supporting schools of awe-inspiring predators.

Together, the three oceans create a rich mix of marine diversity

and an explosion of life

in the magical land of Oz.

Australia's ocean wilderness

is one of the most extraordinary places on Earth.

It is both beautiful and bountiful.

It starts with the tiniest fish...

which, in turn,

support an astonishing array of larger creatures.

Dusky sharks are fast, streamlined predators

that can grow over four metres in length.

Dense schools of sardines on this Western Australian coastline

attract their hungry mouths.

The fish are fast

and their quick shimmering changes in direction

make it hard for the predators to pick out an individual.

Their prey are herded towards the shallows.

In the shallows, there's also a group of young board riders.

Confident that the sharks are keeping themselves busy,

the swimmers have entered the fray for a close encounter.

There are 375 shark species in the world,

yet only three are responsible for most human attacks.

Dusky sharks are not amongst them.

More and more sharks join the feast,

drawn from far and wide.

From higher up, the sheer size of the scene becomes clear.

They have become one colossal bait ball.

A seething mass of predators and prey spreads along the coast,

in a scale rarely seen anywhere else on the planet.

The abundance of fish still teeming in Australia's oceans

supports many marine predators.

But not all of them remain underwater.

Just over 60 kilometres off South Australia

lies Pearson Island.

Often compared to the Galapagos,

this archipelago has a precious cargo of species

found nowhere else on earth.

The Australian sea lion is amongst the rarest of its kind in the world.

Its population reached dangerously low levels

after being hunted for close on two centuries.

The world's least polluted and best stocked waterways

have helped sea lions back from the brink of extinction.

These are ideal fishing grounds for a sea lion mum.

The island's small sandy bay

provides the perfect nursery for her pups.

He's not confident enough

to follow his mother into the waves just yet.

Alone, he watches the more experienced youngsters

mess about in the water.

Perhaps someone close to his own age will provide some company.

But mothers can be protective...

..and fathers horribly hostile.

[SNARLS]

[GROWLS]

The colony can be a dangerous place to wander in search of a playmate.

Mothers come ashore and reunite with their pups for a feed.

[SEA LIONS CALL]

But his wait continues.

In Pearson Island's toddlers' pool,

the young pup has finally found a friend...

..from a different species...

..a long-nosed fur seal pup.

These rock pools at the back of the bay

provide the perfect playground.

[BIRDS SQUAWK]

As the pup's hunger grows, he watches for his mother's return.

Sea lions are some of nature's greatest ocean acrobats.

So simply coming ashore should be easy.

She needs to pick a landing spot.

But the crashing waves are making it hard.

If she's not going to clear a wave in time,

she needs to abandon the plan for a wiser one.

The sandy beach is surely an easier landing site.

[SQUEALS]

As fast as his flippers can carry him, the pup runs to his mum...

..and finally gets his milk.

He will rely on his mother for 18 months

before he must catch his own dinner, like the older sea lions.

One of the reasons sea lions can thrive

in the seas around southern Australia

is the abundance of prey.

And now, in winter,

one of their favourite foods is starting to mass

in one of the most intriguing and graceful animal congregations,

known only in these waters.

In the wide shallows of Spencer Gulf on Australia's south coast,

as the water temperature drops below 12 degrees in winter,

a magical phenomenon takes place.

Giant cuttlefish, up to a metre in length,

are found only in Australia.

Masters of disguise,

they can change the colour and texture of their skin

to blend with their surroundings.

At this time of year, though,

it's all about standing out from the crowd.

This patch of reef, just over a square kilometre in size,

has been inundated with thousands of courting cuttles.

With a ration of 11 males to every female,

not every male is going to get lucky.

This female has accepted the protection of a larger male.

But now he must hold on to his mating rights

in the face of constant challenges from eager rivals.

The males quite literally size each other up.

By splaying out his tentacles,

turning white and angling his body at 45 degrees,

this alpha male attempts to appear larger than his challenger.

The female is hidden below

while waves of black add to his display of strength.

As rivals converge on either side,

it's almost impossible to keep his mate concealed.

While the alpha male is distracted,

his mate drifts from cover.

A smaller male sees an opportunity and moves in.

The interloper drags her as far as he can,

before forcing her into his twisted embrace.

But the larger alpha male is quick to reclaim his prize.

Like a fire hose,

he flushes out the sperm of previous copulators.

As the last to mate, he will be the one to fertilise her eggs.

The pair can finally get down to the business

of finding a place to nest.

Any prospective home for their eggs requires close inspection.

Satisfied, she begins depositing their first clutch.

It takes around six minutes before she can lay another egg.

So the male must guard her closely.

It's a prime nesting place, coveted by other cuttles,

who feel their way closer to the crevice and the fertile female.

One by one, the delicate eggs are fixed.

To stop others entering the cave,

he flattens his body,

making him appear even larger,

doing his utmost to impersonate a monstrous kraken.

Males venture closer, testing his resolve.

His fatherhood is on the line.

It's a warning sign -

stay away from this monster's lair!

Despite the show of brute strength,

challengers persist.

The monster allows them even closer,

until...

Cuttlefish expel ink to confuse predators.

But this is a desperate attempt

to escape the clutches of one of their own...

..the largest male on the reef.

This unique marine spectacle was on the verge of being lost.

In a single season,

commercial fishermen caught 240 tonnes of cuttlefish

at this breeding site,

before a fishing ban was put in place.

Today, these calm inshore shallows

allow this amorous gathering to continue in relative peace,

while further out to sea,

storms are brewing.

In the depths of winter, polar winds from Antarctica

whip up huge swells across the Southern Ocean.

This is the ocean's engine room,

generating waves that will roll across the planet.

And Australia's southern coastline is shaped by this powerful force.

As the ocean swell nears the outer fringes of Australia,

huge waves, as high as seven-storey buildings,

have been recorded off Tasmania.

In winter, many of the ocean wanderers

leave this violent sea scape...

..to seek refuge in the Great Australian Bight.

The arid Nullarbor plain reaches a dramatic end,

as land plummets to the ocean, 150 metres below.

Every year in winter,

Southern Right whales gather in these cliff-side coves.

This female left her feeding ground in the Antarctic,

and travelled over 4,000 kilometres to give birth.

The warmer water is gentle on her newborn,

yet to grow its insulating blubber.

She will nurse her calf here

until it's strong enough to face the long migration south

at the start of spring.

But it's not all gentle play

for whales in these waters.

These cliff-side coves are the arena

for spectacular mating events.

At nearly 15 metres and each weighing as much as 100 tonnes,

four males close in on the lone female.

Dolphins become curious onlookers.

Females are known to go belly-up

in an attempt to keep their genitals away from males,

as they wield their supersized anatomy.

Almost four metres long,

the penis of the whale delivers a gallon of sperm during mating.

Unlike the Southern Right whales,

this dolphin pod remains by the coast throughout the year.

[DOLPHIN SQUEAKS]

And despite the size difference,

the dolphins are happy to share their home with the visiting giants.

The whale even appears to mimic its more agile playmates.

Play tends to be a preoccupation for most of the mammals

in the southern seas.

In mid-winter, surfers also take to the water.

It's a time when waves are often at their best

because of the Southern Ocean swell.

And when the surf picks up,

it's not just people trying to catch a wave.

It's also the dolphins.

Reaching up to 50km an hour,

they rocket through the waves.

Research has shown that these synchronised displays

help male dolphins form alliances.

Of course, surfing's also fun.

[DOLPHINS SQUEAK]

While dolphins frolic,

below the water's surface

there are far darker goings-on.

Port Phillip Bay is on the doorstep of Melbourne.

But very few of its residents, including me,

have ever witnessed the eerie marine spectacle

that mysteriously unfolds in these shallows

for a few weeks every winter.

At nearly half a metre in width,

giant spider crabs are amongst the world's largest crustaceans.

Seldom seen, they spend the year scavenging on the seabed.

But this crab's spider senses are tingling.

It's time for a change.

It's soon joined by others.

Normally dwelling in depths of up to 800 metres,

these crabs migrate to the shallows each winter,

not to mate but to moult,

to shed their old shells.

It's believed the winter's drop in temperature

triggers this mass migration.

Before long, the ocean floor is writhing

with a carpet of claws and spindly legs -

sometimes several creatures thick.

In the world above, life continues as usual.

While just a few metres below,

thousands of giant spider crabs

are entering the most vulnerable stage in their lives.

Scratching at its face is a sure sign

this crab's transformation has begun.

In order to grow, the crab must remove its old shell

and reveal a new one beneath.

Its new orange shell, though larger,

is flexible and able to bend

as the crab works its way out.

However, this temporary softness will prove its downfall.

It's one of the first to expose its new soft shell.

And its hard-bodied neighbours waste no time

in seizing an opportunity for a meal.

When growing a new shell,

crabs need as much protein as they can get,

no matter how macabre the source.

Once a leg is plucked from a victim,

the attacker quickly retreats with its prize.

Despite the perils of moulting in the midst of cannibals,

these crabs are playing a numbers game.

There's a greater threat to their kind.

Smooth stingrays,

armed with venom-tipped tails,

have stalked the crabs to the shallows.

These are the largest stingrays in the world,

but they have no need for toxic barbs here.

Swooping over the scrum of panicked shellfish,

the ray vacuums up the crabs.

Defenceless crustaceans are sucked from their soft shells.

The carnage continues well into the night,

the rays gorging themselves to bursting point.

Yet, with this many crabs moulting at once,

even the most insatiable rays can't eat them all.

But then, a week or two later,

just as suddenly as they arrived,

they are gone...

..disappearing back to the deep,

where their lives largely remain a mystery.

A few leftovers from the feast of rays are all that remain.

One reason for Australia's many marine marvels

is that while the Southern Ocean chills the south,

two more oceans bring warm tropical water from the north.

In the west, it's the Indian Ocean.

In the east, the mighty Pacific.

The huge area of continental shelf shapes life here.

It forms gentle sloping beaches,

and the coast is dotted with islands.

Off the New South Wales coast sits a rather special place.

Cabbage Tree Island is the only island in the entire region

which remains covered in rainforest.

The tall slender palms have given rise to an extraordinary seabird,

evolved for this very specific habitat.

Beneath the forest canopy,

the rocky slopes are littered with nooks and crannies.

And at the right time of year,

a little ball of fluff

can invariably be found inside each one.

It is the world's only breeding colony of Gould's petrel.

This chick is around three weeks old.

It's left alone while its parents are fishing at sea.

The spider poses no real threat.

But best not to take your chances

when a spider's 15cm leg span

is wider than you are.

By nightfall, there's still no sign of Mum or Dad.

But then...

..a somewhat undignified entrance.

But landing takes practice.

And it's a skill seldom used...

..by petrels.

This species spends years at sea without touching dry land.

So walking over a rocky forest floor is an alien sensation.

To make matters trickier,

almost every available hole under a rock...

..has a chick in it.

It's believed the adults use a keen sense of smell

to find their way back to their nest hole.

But it doesn't appear to be a fail-safe method.

Wrong hole.

Finally, after some searching,

mum and chick are reunited,

and chick gets a meal of regurgitated squid.

Over the next 12 weeks, night after night,

crash-landing after crash-landing,

chicks all over this tiny island

will wait for parents to return...

..until the one night when they won't come back.

Four months later, with only a tiny crown of fluffy down left,

the petrel chick has been abandoned by its parents.

It's been weeks since it's had anything to eat at all.

Hunger, desperation and instinct need to sufficiently combine

before it has the will to make its move.

For those who don't, the island holds no future.

The young bird decides it's time to leave the nest.

Seabirds like petrels rely on the wind

to give them the lift needed for take-off.

But down here beneath the forest canopy,

the air is listless.

An ill-judged effort at flight could be its last.

Sharp palms and jagged rocks don't make for good crash mats.

If it's going to stand any chance of getting off the island,

it will need to get out from under the canopy.

But trees cover the whole island.

There's only one thing for it.

And webbed feet and wings are not ideal climbing equipment.

But the petrels here have evolved sharp claws and a hooked beak

to aid their ascent.

As the saying goes, if at first you don't succeed...

Attempting the climb again

pushes the starving fledgling closer to exhaustion.

Panting, the fledging wraps its wings around the trunk

for a moment's respite,

using its tail feathers as a prop to rest.

Frantic wing flapping helps to propel the bird up the tree.

Having made it to the top, more obstacles lie in wait.

The thick stems at the centre of the palm fronds

are lined with sharp spikes.

Feathers are easily entangled.

Part fall, part flight,

either way it's airborne

and it won't touch land again for five or six years.

As the Gould's petrels head off to a life far out at sea,

other ocean wanderers are being drawn

to Australia's Pacific coastline.

Once a year, humpback whales pass Cabbage Tree Island

on their journey north.

They have come to give birth to their young in the warm shallows.

The most famous of all is one of myth and legend.

Migaloo, the albino humpback whale.

His name means "white fella" in Aboriginal language

and his pale colour is most likely due to a rare genetic mutation.

Believed to be 32 years old,

Migaloo is in his prime,

and he knows how to demonstrate his power.

Scientists believe that tail slapping and rolling

is a form of communication between whales.

His companion applauds with a tail slap of its own.

First sighted in 1991,

Migaloo was thought to be the only white whale in existence.

Since that time, newborn white calves

have been spotted in the Pacific around New Zealand and Australia.

It's thought that Migaloo may be the father

of some of these pale youngsters.

Migaloo travels up and down the humpback highway,

as he makes the journey from Antarctica

to the Great Barrier Reef.

And while the reef is famously home

to some of the ocean's most colourful characters...

..it's also home to some of the ocean's most endangered.

Ancient mariners, such as the green sea turtle,

have for thousands of generations returned here every year.

She has come back to lay her eggs in the very same place

where her life began.

With flippers designed for sea and not sand,

hauling her 200-kilo body up onto the shore

is an enormous effort.

The expectant mother is able to carefully carve out

a nest in the sand...

..her one and only act of parental care.

She deposits a clutch of around 100 eggs.

As she returns to the waves, more mothers clamber up the beach.

In fact, many, many more.

14,000 turtles can come ashore here in a single night.

In a single year, the turtles of Raine Island

could lay as many as 36 million eggs.

Two months later, the sand begins to stir.

A hatchling begins its frantic race to the water.

But by night, ghost crabs haunt this beach.

Flapping flippers are its only defence

in a desperate attempt to get free.

Exhausted from its escape...

..it unwittingly walks right into the arms

of a waiting ghost crab.

But luck is on its side.

Running the gauntlet,

the baby turtle makes it to the open ocean.

It's estimated that just about one in a thousand hatchlings

survive to adulthood.

From here, the young turtles travel on currents circling Australia.

Some will swim further east into the South Pacific.

Others may travel north towards Asia.

The separation of the land between Asia and Australia

creates a passageway for tropical water to flow.

Because of this, it's the only continent

with warm water flowing south on both coasts.

Currents jettison into the Indian Ocean,

and the rush of tropical water spills south

along the Western Australian shore.

This coastline is the world's most pristine...

..an example of what marine ecosystems should look like -

healthy, interconnected,

teeming with life.

30 kilometres off the Kimberley coast lie the Lacepede Islands.

18,000 pairs of brown boobies nest here.

A new pair of boobies is hoping to start a family.

Their courtship is under way.

With a weedy offering, he attempts to woo her.

Perhaps another try.

No, surely his efforts have been sufficient.

But maybe not.

At the height of the breeding season,

chicks of all sizes crowd the rocky shore.

As with humans, boobies approach parenting in a variety of styles.

Some respond to the nagging of the chicks immediately.

Others are less attentive.

Chicks born earlier in the season

are taking part in beak skills lessons.

Becoming adept at flipping sticks and stones

will help with manipulating slippery fish mid-flight.

As the temperature rises to over 40 degrees,

parents hover like a beach umbrella over their chicks.

Communication between this pair is on point.

They are the perfect tag team,

taking domestic duties in turn,

allowing the other to go fishing.

Out at sea, the boobies move en masse.

They have spotted splashing in the distance.

A school of tuna and sharks

have driven a bait ball of sardines to the surface.

Before long, frigatebirds join the plunder.

Having got their fill, the birds head home to their hungry chicks.

Some frigatebirds haven't bothered to head out to sea.

There's good reason these birds are known

as the pirates of the skies.

Larger and faster than the boobies,

they can bully the smaller seabirds into giving up their lunch.

Outmanoeuvred, it's forced to disgorge its food in midair.

Yet another chick will go hungry.

On shore, the tiny chick's wait for a meal should finally be over.

The mates greet each other, but lunch was stolen.

Now the onus of providing a meal falls to the other parent,

with added pressure.

Fortunately, it's the time of year

when the westerly winds strengthen the flow of currents,

fueling the plankton blooms.

This sudden bounty of food attracts many mouths...

..including the biggest fish of them all, the whale shark.

Despite their imposing size...

..they feed on microscopic plankton.

Chemicals released by the plankton are carried on the ocean current.

The whale sharks follow their sensitive noses

to find these blooms in the waters of Ningaloo.

With a large resident population of whale sharks in the area,

scientists want to understand

how individuals are related to each other.

To do this, the scientist needs a sample of each whale shark's DNA,

and he's come up with a rather unusual way of doing this.

Remarkably, the giant animal will hang very calmly in the water column

whilst its nose is scratched.

Completely relaxed,

the shark seems to enter a dream-like state,

allowing the scientist to scrape tiny parasites off the shark's body.

These parasites, known as copepods,

chew the shark's skin

and drink their blood.

In return for the DNA sample,

the whale sharks get rid of a few freeloaders.

Research has now shown that Australian whale sharks

are the offspring of ocean-wandering parents,

from as far away as Indonesia and Papua New Guinea,

where they can be targeted by commercial fishermen.

Here in Ningaloo,

the juvenile giants have a precious sanctuary

where they are a protected species.

These gentle creatures prove not all sharks are ravenous meat eaters.

But in Australian waters,

there are always other sharks who fit the stereotype.

Shark Bay, in Western Australia,

and the water is as warm as a bath.

The faintest trace of blood in the water sends a signal.

While an entire whale carcass is like a siren going off,

alerting sharks for miles around.

Tiger sharks.

Threatened globally,

but here it's a recently discovered hotspot

for these majestic predators.

A frail old whale, having succumbed to its end,

becomes a banquet for the tigers.

These perfect predators have hunted the world's oceans

for more than 50 million years,

but they're not above a bit of scavenging.

The feeding frenzy has attracted tour boats.

The passengers are treated to ringside seats

for the grisly feast.

Such impressive schools of predators

show Australia's ocean wilderness

is still filled with life.

Predators are the ultimate expression of a healthy ocean.

But while scenes like this once dominated our planet,

today they are ever diminishing.

Such a rare and remarkable spectacle

is also a reminder of whose territory the ocean really is.

The abundance and diversity of Australia's ocean realm

provides another opportunity...

..for the island nation to lead the world

in marine conservation,

at a time when global oceans are under threat.

Australian waters not only nurture unique species found nowhere else,

but also provide protection to species from distant shores.

And because of this,

there's no underwater world more worthy of safeguarding than here,

in the magical land of Oz.