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ATTENTION

EPISODE 8

Much of our planet still remains unexplored.

For most of it is covered by water.

Every journey below the surface can reveal something extraordinary.

More than a thousand new species are discovered here every year.

The ocean is home to 80% of all animal life on planet Earth.

But today, thriving in this varied world

sometimes demands the most surprising behavior.

The shallow seas of the tropics.

This may look like a paradise.

But beneath the surface, it is an arena for constant life

and death struggles. Where not everything is quite as it

seems.

A predatory lionfish.

On the hunt for shrimp and small fish.

With so many places for its prey to hide, the lionfish has to be patient.

This shrimp appears tempting. As the lionfish closes

in, it fans out its fins to disorientate its prey.

The hunter becomes the hunted.

Tricked by one of the shallow seas most extraordinary predators.

A clown frogfish.

On its head, it carries a fishing rod. A modified dorsal

fin, baited with a lure. Easily mistaken for a shrimp.

But when the fish stop biting, it's time to pack the rod away and move on.

And for a frogfish, that takes time.

Rather than swim, frogfish walk. Its fins have, in effect, become feet.

It may not look pretty, but what appears to be

coral living on its skin is actually camouflage.

As every good angler knows, picking the right spot is important.

Jigging the rod sends out pressure waves to attract the attention of possible prey.

These dragonettes are certainly interested.

Almost there.

Hook, line and sinker.

Like all shallow seas, the cold waters off the coast of

North America benefit from the intensity of the sunshine.

Here, that fuels one of the fastest growing organisms on the planet.

Giant kelp. Towering forests can eventually reach the height of a 12-story building.

These forests are nurseries for young horn sharks.

As the sun begins to set, they leave their daytime shelter

and set off into the heart of the kelp forest to find food.

Nearly half a meter long, this little shark is extremely vulnerable.

There are monsters here. A giant sea bass, weighing over 200 kilograms.

And wolf eels with big teeth that can crush little red sea

urchins. But the biggest danger comes from other sharks.

Hound sharks.

And huge, broad-nosed sevengills.

In this forest, it pays to keep a low profile.

An angel shark.

One of the most deadly sharks in the kelp forest, and certainly the best camouflaged.

An angel shark will lie in wait for days.

But this one has already attracted too much attention.

It's not welcome here.

Now the coast is clear.

But angel sharks hunt around the clock.

Openings for breathing called spiracles blow out sand that helps cover its body.

The trap is set.

Staying close to the seabed is a good way to avoid most predators.

Faster than the blink of an eye. But it's not over yet.

Horn sharks have a secret weapon.

Sharp spikes keep them very much off the menu for most.

So this young horn shark can hunt in safety for now. But it's

not

over yet. Violent winter storms batter these kelp forests.

The plants can be ripped from the seafloor and

carried away far out to sea.

The open ocean is a vast, featureless desert.

Even a small piece of drifting kelp can become valuable.

It's just what these fish have been searching for.

Here, shelter where eggs can be laid unobtrusively is rare.

So they make the most of it. Each female produces up to a

thousand eggs and the males rush in to fertilize them.

All this activity attracts the attention of blue sharks.

They can travel thousands of miles through the ocean in search of food.

And they may not have eaten for weeks. It seems that they're in luck.

But these fish are no easy meal.

They are flying fish.

Music The blue shark, however, are not here for the fish.

They have come for the caviar.

But flying fish lay so many eggs that the shark's feasts hardly make an impact.

And in a few months' time, a new generation will take to the skies.

Floating islands of weed are always attractive to creatures

looking for shelter out in the big blue. But in today's

ocean, they're being replaced by something else.

Plastic.

Twelve million tons of it end up in the ocean every year.

The deadliest kind are discarded fishing lines and nets.

Each year, it's likely over half a million animals

are ensnared and killed by these ghost nets.

But some animals are learning how to take advantage of the plastic rafts

and use them for shelter or even as a home.

This male Columbus crab, barely bigger than your thumbnail, is a castaway.

Clinging to his net, he may have been drifting on ocean currents for months.

Now fully grown, he needs to find a partner. But where?

Certainly not here, alone on the net.

Columbus crabs are not good swimmers, so this male is marooned.

Perhaps a passing loghead turtle could be the chance to hitch a lift.

Made it.

But there is more than one passenger here. A female Columbus crab.

They waste no time in getting acquainted.

And start to mate.

This pair may well stay together for the rest of their lives.

The turtle, after all, makes an excellent home.

In return, the crabs provide an onboard grooming service.

Finding a partner in the vast ocean is not easy.

Dawn in the Sea of Cortez.

Mobula rays.

They're gathering here, most likely to breed.

No one is sure why they leap, but the loud

splashes certainly seem to attract more rays.

Other creatures, however, are also listening.

Orca have heard the splashes.

This female specializes in hunting rays.

But today, she is teaching two youngsters the finer points of mobula ray hunting.

The rays are fast and can outmaneuver an orca.

She knows she needs to herd the prey into a tight group.

But she can't do that on her own. It'll take teamwork. And that is today's lesson.

The young orca are quick to catch on.

The rays are surrounded.

They dive.

Only to be forced back up again by the experienced female.

And now, with the exhausted rays trapped against the surface, she attacks.

And the young ones follow her lead.

This family are the only orca known to hunt

rays like this. And they are lethally efficient.

But it appears that school is over for today. For a

few battle-scarred survivors, it's a lucky reprieve.

With the orca gone, the rays can resume their courtship.

And they do so in astounding numbers.

Tens of thousands of rays in a single show.

Vast areas of our ocean are yet to be explored.

The least known parts of it are its great depths.

Only highly specialized vessels can take you there. As you

descend, the sunlight rapidly fades.

Two hundred meters down, you enter the twilight zone.

An alien world inhabited by creatures beyond imagination.

A siphonophore with a cloak of lethal, stinging tentacles.

Siphonophores repeatedly clone themselves, and so grow to immense lengths.

This one measures forty-five meters, and is the longest animal ever recorded.

With such deadly predators around, creatures here go to great lengths to hide.

A glass squid,

completely transparent, except for its eyes and

stomach. So it is extremely difficult to find in the gloom.

Below one thousand meters, all traces of sunlight

have disappeared. This is the midnight zone.

Catching food in the perpetual darkness is not easy. A gulper

eel.

Its giant, extendable mouth can engulf prey larger than its own body.

Two miles down, you finally reach the ocean floor.

We know more about the surface of Mars.

The pressure of the water is three hundred times greater

than at the surface, and it's freezing cold. Yet amazingly,

there are animals living here.

Mus octopus robustus, nicknamed the pearl octopus.

Breeding in these extreme conditions poses a particular problem for these animals.

At these low temperatures, this female's eggs could take over ten years to develop.

So she travels to a very special place.

This is the largest known gathering of octopus in the world.

She joins twenty thousand other females, all here to lay their eggs.

Water, heated deep in the Earth's crust, rises through cracks in the seabed,

raising the temperature to as much as ten degrees Celsius. A deep sea thermal spa.

This warmth significantly speeds up the development of their

eggs. Even so, they will still take nearly two years to

hatch.

Once a female is settled, she won't move from her spot. Not even to feed.

She will constantly tend to her brood, keeping

them clean and oxygenating them with jets of water.

Pearl octopus mothers must surely be amongst the most devoted.

After almost two years, the ordeal takes its toll.

But the vigil is almost over.

The last of the brood's

eggs. The brood are gently encouraged to leave.

But this will be a final act. Like all the mothers

here, this octopus is starved and exhausted.

Her life will soon be over.

But this devotion means that her offspring are among the

largest and most developed of any octopus. And have the best

chance of survival in the demanding world of the deep.

We are finding more of these strange hot springs every year.

In some places, they can be astonishingly violent.

Superheated water, hot enough to melt lead, spouts from the

seafloor. Dissolved minerals condense around them to form

towering chimneys known as hydrothermal vents.

They are home to unique communities of animals that

all rely on the nutrients in the scalding water.

Some suggest that vents like these could be the places

where life on Earth first began four billion years ago.

And there is now evidence of hydrothermal vents on the moons

of Jupiter and Saturn. Could they too be supporting life?

Here on Earth, the influence of these vents extends far

beyond their chimneys. The essential nutrients carried in

these plumes can rise all the way to the surface two miles above.

Here they stimulate the rapid growth of tiny marine plants on an astronomic scale.

This phytoplankton is so abundant that it produces half of all the oxygen on Earth.

It's also food for a host of minute animals.

Zooplankton.

Together, they are the basis of the food chains

that sustain nearly all life in the ocean.

In the Pacific waters off South America, they

feed anchovy that gather here in buildings.

This is one of the world's most productive ecosystems.

These South American sea lions are on the hunt.

But the anchovy shell has already been located.

By the planet's most efficient hunters.

A net over half a mile long encircles the shell.

It can trap over a million fish.

But the sea lions aren't about to go hungry.

They have learned to look for holes in the net.

Why waste energy when food comes to you as easily as this?

As more and more sea lions arrive, some change their tactics.

They line up on both sides of the net and wait.

As the net tightens, the anchovy panic and rush for the surface.

This is the moment the sea lions have been waiting for.

It's such an effective way of hunting that the sea

lions here are changing their natural behavior.

And are raiding the fishing nets in their thousands.

With the net almost drawn in, the fishermen beat out a warning signal.

Time is up.

In the confusion. Not everyone manages to escape.

The trapped sea lions are in danger of being drowned.

The pups are separated from their mothers. The

pups are separated from their mothers. The pups

are separated from their mothers. The pups

are separated from their mothers.

Then at the last minute, the fishermen briefly drop their net.

And the trapped sea lions can escape.

And many are not so lucky. Around the world, millions of

animals are accidentally caught and die in fishing nets

every day. And this bycatch, as it's known, is pushing many species toward extinction.

Animals have evolved in remarkable ways to the demands of life in the ocean.

But can they now adapt to the new challenge, living alongside us?

The open ocean is home to some of the largest and most

extraordinary animals on Earth. But here, off the Canary

Islands, the Planet Earth team are searching for one of its

smaller and less familiar residents. We're looking for a

tiny creature called a Columbus crab, which is only about

the size of your thumbnail, which live on floating objects

in the open ocean. Columbus crabs were once only found on

natural debris like driftwood or seaweed, but the oceans are

changing and they've been forced to adapt. One of

the

most common items they find is discarded fishing gear.

Over a million tons is left to drift in the ocean each

year. And Columbus crabs are now making their homes on these

unnatural materials.

Surprisingly, Columbus crabs are thriving on this new habitat.

But for larger ocean creatures, these nets can be lethal.

Loggerhead sea turtles are especially vulnerable.

Many times they are very injured and many times

they don't even survive. It's a sad situation.

As a rule, wildlife filmmakers observe natural behavior and do not interfere.

But this is far from natural. The team feel they must take action.

It seems that the turtle is quite OK. We'll just

finish to cut the plastic and then we release it.

It's a bittersweet moment, as this is one of eight turtles

they rescued whilst filming here. This situation is not

natural. It's something that is being caused by human beings.

Sadly, the crew now face dilemmas like this on many of their filming expeditions.

Including when they travel to the Pacific coast of Chile to

show how sea lions are competing for food with one of the

biggest fisheries on Earth.

Expedition leader Fernando Olivares takes the team to the fleet.

Diving near fishing nets is extremely dangerous, so the crew

must ensure they have the full cooperation of the fishermen.

It's a pretty hazardous place to dive. It's just a case of

trying to keep an eye on the divers, but the sea lions also

like to go down and blow bubbles, so you'll think you're

following the divers and then a sea lion will pop up.

Taking the utmost care, the divers get a close-up

view of the sheer scale of the operation.

This one net must have about 15 tonnes of fish in it, and

there's eight or nine boats in this one little bay. And

these are just the small boats. Out there, there are huge

factory ships that are taking even bigger catches. How much

fish a year from just to here? From a million tonne a year, more or less.

The catches are so vast that sea lions have changed their

natural behaviour to collect anchories directly from the

nets.

But it's a risky strategy. The crew witnessed sea lions

caught in nets multiple times. Wow, it's intense, mate.

There's so many in there.

There's a puff stuck in the net, calling to its mother, and

its mother's just on the outside of the net, calling back.

That's really hard to watch.

The puff's really panicking now.

Sometimes, fishermen are able to release trapped sea

lions. But not this time. The puff is in serious danger.

Once again, the crew decide to step in. He's

going to go inside of the net to save him.

No,

no, no.

Nice,

really nice. It's a relief this time. But it highlights the

new realities of filming wildlife in today's changing ocean.

Thank you for watching!