Original subtitles

The Ocean....

the last frontier on earth.

So much is unexplored and unexplained.

To change that...

a kickass team of insanely talented specialists is

setting out to push the frontiers of what we know

about our oceans.

Oh my gosh.

Zoleka Filander, deep sea scientist.

Being a deep-sea researcher means

having front row tickets to the best movie that everybody

wants to watch.

Melissa Márquez...

Straight ahead, 12:00.

Shark biologist.

We just saw what no one has seen before.

Eric Stackpole...

Scan now!

Ocean tech innovator.

I love building tools that allow us

to see things in ways we've never seen before.

And Aldo Kane...

This is insane.

Former Royal Marine; special ops.

It doesn't get any more cutting-edge

exploration than this.

Their secret weapon...

...the OceanXplorer.

The most technologically advanced research vessel

ever built.

There's never been a more urgent need to understand

our ocean and the animals that call it home...

Because their lives and ours depend on it.

This time the team takes on a deep-sea shark.

She's huge.

And get closer than they ever imagined.

Oh she just hit the sub.

The OceanXplorer is in the Azores.

A group of volcanic islands

in the middle of the Atlantic Ocean,

1,000 miles west of Portugal.

For this mission, the team is heading into the deep.

To uncover the secrets of one of the ocean's

most elusive creatures.

The sixgill shark.

These animals live at depths of over 4,000 feet...

and are so perfectly adapted to the abyss, it's believed

they've barely evolved in 200 million years...

they're as old as the dinosaurs.

Sixgill sharks are secretive,

I've spent hundreds of hours in subs,

I've only ever caught glimpses.

They can live so deep they're really difficult to study,

so the team is here to push the scientific frontiers of

what we know about these animals.

We will be rolling the subs out in just a

couple of minutes.

To reveal the shark's mysteries, the team

will make a series of dives into the sixgill's world.

I've always been fascinated by the deep

because it is so unusual, it has this feeling of being

scary but your curiosity makes you go anyway.

Move into position for the sub launch.

Their ultimate goal is to tag a shark

in an ambitious plan.

Nobody has managed to tag a sixgill shark

from a sub at depth and get the data back, so what we're

doing here is really pushing the boundaries.

Ready for passengers.

Melissa Márquez studied sharks for her PhD,

but she's never come face to face with a sixgill.

I'm gonna be a little intimidated if I've got

a sixgill coming straight at us in the sub.

I mean these big animals and it definitely, if it wants to

clamp on to some part of the sub and shake us around a bit.

Just through here?

Just this way, up the steps, sit here hands either

side and lower yourself down.

So yeah a little bit nervous of getting

up close and personal with them but really, really excited.

The team is joining forces with Jorge Fontes

and Pedro Afonso,

shark scientists from the University of the Azores.

There's amazingly little known about

these creatures, in spite of the fact that they are

the top predator.

Right can I...

Yeah, just put your feet there and then down

on to the seat.

It's good.

The first mission is to observe these

well-adapted sixgills, which survive in a cold, dark world

of intense pressure and to get an idea of how many there are

in this area.

Clear!

Neptune hatch secure, life support running,

safety brief complete, ready for the water.

It's really happening.

It is.

You ever been in a sub before?

Nope, my first.

It's 10:30 pm.

Pedro knows where the sharks hang out at night, but until

now he hasn't had a chance to go there.

Ok bridge all ready.

All stations SO, launching Neptune.

We know that the sharks spend their days in

the depths of the ocean, and that every sunset they start

an epic three hour journey

nearly 1,800 feet up to this island ledge.

Melissa and Pedro are hoping to meet them there.

Down here light barely penetrates,

and temperatures are just above freezing.

See the bottom?

- Yep, yep. - Yeah, really close

Now we see it.

OK here we go.

Just so much biomass here, there's got to

be some sort of nutrient rich water here,

some sort of upwelling,

to explain just how much we've got going on right now.

Melissa and Pedro will stake out this

ledge for eight hours.

Just 20 minutes in, a shape emerges out of the darkness.

Shark, shark, shark,

OK, here we go... Port side, port side.

A sixgill shark.

That's huge!

Adult, definitely an adult, about 15 feet long.

Female, no yeah

Yeah female.

Males are identified by their claspers,

their sexual organs under the pelvic fin.

It's so interesting,

that she's so sluggish.

Guess she is conserving her energy, I mean it's cold out

there, it's only 39 degrees.

The sixgill is different from almost

all modern sharks.

It has six pairs of gills, instead of the more normal five.

A relic from the ancient conditions they evolved in.

They really look like a prehistoric creature.

Literally unchanged since the Jurassic,

perfectly adapted.

Sixgill sharks are the masters of the deep,

they've got specialized eyes that actually allow them to see

in really low light conditions down there

and that area is pretty hypoxic,

so there's not that much oxygen.

So their blood is actually adapted to being able to

extract more oxygen from its surroundings, so these animals

can actually thrive down there.

This close encounter is a good start,

but we need to know more about these Jurassic sharks.

No one knows how many sixgills are living

here so Melissa and Pedro are carrying out a population

survey throughout the night.

Think it is, yes, it's coming.

Do you see it?

Oh yes, yes there it is.

Yep. It's coming.

Ohhh shark.

Shark?

Yep.

A small one...

Ah... not so small.

No, not so small.

These sharks were showing

all different types of personalities.

She's under. She's under.

A hell of a big shark.

Some were really interested in the sub.

That's a big tail.

Woohoo, it's really close.

You can feel the power.

Some wanted nothing to do with it.

As the hours go by, they count 11 sixgills,

one juvenile male and ten females.

It's interesting that we haven't

really seen any males here, just that one, it's mostly

just been females, no boys allowed, females only hangout.

Shark mating be violent and outside the

breeding season many species of shark carry out segregation

of the sexes, it looks like this could be happening here.

Our team has confirmed that this is a sixgill hotspot.

Now the likely reason they come here is to feed,

but how are they hunting?

To find that out the team is attempting to tag a sixgill

from a sub.

The submersible team has fitted the tag deployment rig.

Set of lasers here, and that will give you an

approximate position within a few centimeters.

The whole team is feeling tons of

pressure, because there's so many things that could

go wrong, when doing this from a sub.

Everything's got to line up perfectly to

make sure we get this once in a lifetime shot.

There's only been one previous attempt to

tag a sixgill from a sub, but the data was never recovered.

For this mission,

Pedro and Jorge have developed a hi-tech prototype.

These electronic tags allow us to go

much further into a window onto their behavior,

they combine very, very fine scale sensors that tell you

the movements of the animals.

Succeeding in this mission, will mean

getting even closer to the sharks.

All the planning has come down to this dive, the pressure is on

for Melissa and sixgill researcher Jorge Fontes.

We just need to find the right shark with the

right attitude.

That has to be confident and get in the right place at the

right time, so the tension builds up.

The tagging system is carefully primed,

ready for firing.

I think we're good.

Ok guys what do you think?

Yeah looks good.

This is gonna be shark bait, this is

basically the way that we're gonna get the sixgills to come

towards the sub...

Oh god that's gross... I'm gonna smell for days.

All stations, all stations SO.

Launching Neptune.

The sub is diving in parallel with the ROV,

the Remotely Operated Vehicle,

which sends a live feed back to the control room,

where the rest of the team can watch and hope.

There it is, lower right.

Observing animals in the deep is

one thing, but trying to tag one at depth,

that's a different ball game altogether.

As the sub descends to the sharks' hangout,

they encounter a shoal of boarfish.

Wow.

Woah, look at that.

It's a really dense aggregation,

the lights of the sub could be illuminating the plankton they

feed on and they've come in to eat.

These guys are bait fish, everybody

eats these guys.

Have you ever seen so many fishies?

At very very few places, this is pretty wild.

These boarfish are everywhere.

Yeah. Feeding frenzy.

Is it just cos of the bait, it's got to be.

Could be the lights.

Control, Neptune I have you loud and clear

on bottom 255 meters.

Copy Neptune.

OK I'm gonna hand that to you.

It's midnight and the sharks have completed

their journeys from the deep,

but will they come towards the sub?

Come on big mamma.

Hey, you guys we got a shark, yeah coming in coming in,

it's coming this way.

Wow.

OK well here we are.

I love how she's really just taking her

time just assessing the situation.

It doesn't seem super excited about the bait.

I wonder what's distracting it.

Come this way.

Come on.

This adult female has detected a morsel

of fallen bait, and avoids going up to the sub to feed.

Oh you're kidding me.

You cheeky girl.

The sub team must be so frustrated right now.

I'm frustrated.

.

I have lost sight of her.

Oh big shark!

There's two.

Oh there's two of them now.

Oh my gosh.

Well that might get them competing for the bait.

Sixgills will congregate if there's food

around, and that can lead to aggressive behavior.

OK we've got that second one right there.

OK.

Woah, she just hit the sub.

It just hit the sub.

He's under the sub.

Ohh it is mad.

.

With a shark in direct competition, this

female has made it clear she is large and in charge.

You're not armed.

When you want to be armed you let me know.

This is a good time.

It would be a good time now.

Come on come on.

Ok lasers are on.

Number one right?

Alright, it's armed.

OK this could be it.

Alright it's heading this way.

Slow.

He's gonna take it, he's gonna take it,

take the shot.

Ah damn it.

Oh!

Huh, I can't believe it.

Jorge overshot by a matter of inches.

We're not done!

We have one spare.

If they can't get this tag on,

they will fail in their mission.

Oh there we go.

Another sixgill,

this one is alone and she's focused on the bait.

Smell that nice blood.

- Yeah there you go. - Yeah!

The shark needs to follow the end of the

pole to the bait, and line up precisely in the laser beam.

This is a big shark.

This is it, you got this.

Wait until you see the lasers.

This is it.

Right here come this way this way this way.

Nice one.

Camera tag away, camera tag away.

You did it!

They got it. It's tagged.

- Oh yeah. - Hey, hey.

Wow.

The tag is suspended

six feet above the shark,

they can now, for the first time,

follow its movements in detail through the deep.

Here, here's a shark coming right towards us

and I think that's the tag.

This is the one we were holding just moments ago...

this was in our lab up on the desk.

That's really cool.

I'm really excited, we've successfully

tagged a shark,

and if all the electronics are working properly,

and the software's working properly, we're recording data

that basically no one has ever had before.

But the shark is in no rush to leave.

You're back for more huh?

You can, you can have some fish yes.

Look at her eye, look at it roll back.

Sixgill sharks don't have that nictitating membrane so they

need a way to somewhat protect their eye, just in case the

prey fights back.

The tag won't hurt the shark...

its sensors record speed, depth and movement,

for the next 12 hours,

then it detaches and floats to the surface.

But if the team can't recover it,

they won't find out how the sixgills are hunting.

The next day, the tag has surfaced and

pinged a satellite with its GPS coordinates.

So I'm going out to collect the tag, if I can't

get the tag, then all that data will be lost,

and that means all the hard work of tagging the shark

will be in vain.

The precious tag is being swept dangerously

close to the cliffs.

Guys.

Keep your eyes on the water now.

Tag, tag.

OK Aldo I'll get on the starboard side of it so

you grab it on portside.

Yeah. Do you see it?

Yeah seen.

Oh man this is close huh?

Aldo has one chance to pluck the tag

from the swell.

Alright. Alright.

There we go.

Good job, man.

Good job.

The tag has been successfully retrieved,

but what's it going to show us?

The information from the sixgill tag has been processed

and the results are ready to be revealed.

What have you got for us?

I have got some of the best footage

captured from our many hours of shark exploration.

Shall we hit it maestro, ok here we go.

So this obviously is the light from the sub

as seen from the shark.

That's the sea floor.

And I noticed in some other parts of the

footage, you can actually see the fish scattering...

Yeah.

As the shark moved through.

This is kind of how the shark sees it, you know so

you almost get, you get in the mind of the shark.

There's Jorge.

.

I've taken so many pictures of sharks in

my studies, now a shark's taking my picture!

Now it's chomping down on the bait.

The motion sensors on the tag will detect

when the shark is eating, even if you don't have video.

Oh right because it's bobbing

up and down.

But can the other sensors reveal how the

shark may be hunting here?

Here on the top line, will be depth.

So we can see that from here

he was going away from the sub for periods,

because he's going deeper and then he's coming back up,

then he's going deeper, he's coming back up.

So, he's roaming, he's exploring.

Then you can see as we go over, that this is a big climb.

Yep.

You know it's climbed up to 200 meters, then

it goes back down again, and then the nice thing is towards

the end of the deployment it just starts going down and

this is when... sun is about to rise.

Sunrises.

So as the sun's coming up the last thing

we see this shark doing is going down deeper into the abyss.

Straight down.

Here you have speed, so you can see speed changed

you know, varied a little bit.

Do you see a few places like here and here

where the speed increases rapidly for a moment.

What do you think happened there?

Could it be predation?

Could be.

And you know it's interesting that it's

coming up because I know a lot of these predators,

they look for silhouettes.

I mean I guess there's no light at this point I thought

maybe it could...

Maybe enough for them, you know, just moonlight

is enough for them to see a silhouette...

Wow.

Because they have very sensitive eyes.

So, so it could have come from below,

seen its prey come up, eaten it, that's what this spike is

then it's gone back down or something.

It could be.

The shark's upward movements are intriguing

and may be helped by its huge oil filled liver,

that accounts for over 20% of its body mass

and makes it buoyant.

This buoyancy could be behind its hunting strategy.

Some scientists suggest that

sixgills are ambush predators gliding up to capture their

prey, they just hit 'em from below.

Yeah I mean we know from their gut content

that they're mostly eating things

- that are way faster than they are. - Yeah.

So stealth gliding to sneak up on their

prey makes a lot of sense.

The tag results suggest an interesting

hypothesis on how the shark may be hunting,

but our guys need more information.

Can they capture footage of a sixgill actually predating?

To give themselves the best chance, they have to time

their dive perfectly to when there's maximum prey.

We know that at night many creatures come up to feed.

A mass vertical migration occurs in all the world's oceans,

triggered by the rise of plankton,

fish, jellies and squid travel through

the ocean's twilight zone,

and following them, larger creatures.

If they can hit the peak of this vertical migration,

Melissa and Pedro may have a chance of recording

a sixgill on the hunt.

Keep that biologist's sharp eye on

the camera, yeah?

No pressure.

Aldo's also preparing a dive, but his will

be in the shallows, to understand the scale of the

vertical migration in the Azores.

As a former special ops Royal Marine,

Aldo is the only member of the team

with the experience to lead this night dive.

When you have moving boats and diving operations

and then you add into the mix nighttime operations

you can quickly and easily lose control of things.

It's 11:30pm,

only if they've timed their dive perfectly,

will they fully experience the vertical migration.

OK guys are you ready, so 3, 2, 1 go.

Guided in the darkness by his dive computer,

Aldo descends 60 feet.

Immediately he's engulfed by

the smallest creatures in the ocean,

the plankton, that underlie the entire food chain.

This is the vertical migration that

we're talking about,

all of these fish coming in to feed on the plankton

which has made its way up to the surface.

It's amazing, look at all the fish coming in below us now.

Tonight, the rise of the plankton is

followed by something else...

purple stinger jellyfish.

It's amazing seeing them all migrating

up to the surface.

What appears to be a few at first,

grows into a mass bloom.

I've never seen anything like this.

This is literally thousands and thousands of jellies.

It's one of the strangest things I've ever seen,

they're just stunningly beautiful, ha-ha in its own way

The vertical migration is at its peak.

The deeper waters are now rich with shoals of fish,

and the ledge where the sharks make their nightly visits,

is a hive of activity.

It's dinner time.

It's an Angler fish.

See that's the lure, look.

Oh yeah.

He's lifting the lure right.

Yeah, yeah, yeah.

See he's waving the lure.

Yeah.

That's what he uses to attract the prey, then.

A bunch of rays around.

That's so cool.

We just saw a predation.

Conger eels rely on the vertical migration

for food.

They're in feeding mode, that's for sure.

Yeah.

Actually, being down in the sub and putting faces to the

animals that make up this migration, you've got fish

eating smaller fish, you've got the skates and the rays

burying themselves and eating their own fish.

This happens on a massive scale, every single night in

our ocean and the fact that I got to kind of sit in the

middle of it and observe it all is mind-blowing.

These large creatures are perfect prey for

sixgills, but can the team film the sharks actually hunting?

This female has completed

her three hour journey up from the depths.

There we go,

now it's coming a little bit closer.

Yeah cos I got her on camera.

Yeah she is.

She's staying close to the seafloor.

Something's got her interest.

A conger eel.

The conger eel escapes,

but this sixgill is on the prowl

and she's not the only one interested in the seabed.

Oop, there we go.

Yeah, yeah.

She's really low to the ground.

Like all sharks, sixgills have highly sensitive

electrical sensors around the nose,

which can detect the smallest muscle twitch of its prey.

She may be seeking rays hiding out under the sand.

Suddenly she makes a move.

She thrusts with her tail, to get on top of the prey.

Do you see anything in its mouth?

Capturing this behavior on camera

is incredibly special

and will help the team understand how

this top predator hunts.

Oh man that is quite something.

See why we want to study these guys?

Yeah of course.

As a scientist you always hope you get to experience the

rare and extraordinary,

it doesn't get much rarer than this.

That footage is incredible, has that been

filmed before?

No we don't think so, which makes it even

more exciting, because it's probably a first for science

and you know you don't really get that that often.

You know the data from the tag was telling us one thing,

but our own eyes are telling us something

completely different.

Right on the tag data I assumed it was like

an ambush predator where it sees maybe like the silhouette

from below, it snatches its prey.

But that's not what we saw here,

it's using its positive buoyancy to actually lift up its rear end

so its nose eventually actually points down in to the

sand once it finds prey and with that really powerful tail

grind down into the sand.

So it's using its positive buoyancy to,

to glide up the gradient and then pin whatever it is,

the ray, down in to the sea bed.

That's it and that's not to negate the

theory that we got from the tag it just means they might

be using different hunting tactics for different prey.

It's mind blowing to see a brand new to science data point

that we didn't have for these animals before.

I'd call this a pretty successful mission.

Oh 100%! 100%.

In their time here, the team has gained

important new insights into the lives of the sixgill sharks.

They've observed how they're perfectly adapted to the abyss.

It's so interesting seeing them be

so sluggish.

Discovered their different personalities.

You cheeky girl.

And confirmed that a large population of

females live here.

Only a handful of people have been

able to see these sharks from a sub, at depth,

with their own eyes, I feel really lucky to be one of them.

There it is, lower right.

By successfully tagging a sixgill

from a sub...

- You did it! - Oh yeah.

They've gained a whole new set

of scientific data.

This is awesome guys.

What we've done has paved the way for sixgill research and

it has been awesome to be a part of this mission.

They've explored these rich waters of

the Azores at night.

It's one of the strangest things I've ever seen.

Being in the middle of that vertical migration

was just unbelievable.

The greatest achievement,

has been capturing the sixgill's predation behavior.

We know so little about the residents of

the deep, but today we have gained some valuable insights

on how these prehistoric animals have survived.

Some of the sixgill's secrets have been

uncovered, but there's still so much more to learn

about these mysterious sharks of the abyss.