All language subtitles for Great.Blue.Wild.S03E01.WEBRip.x264-ION10

This is the sardine run.

The world's largest marine
migration.

It's like the greatest showon earth.

It's madness.

It's absolute chaos.

There's so much energy
and so much life.

Whooo, look at that ball!

This mass of fish on the
coast of South Africa,

draws the ocean's most
feared predators.

It also draws one of its mostdocile,
the manta ray,

an unlikely guest.

As I'm jumping into
thesewaters that are full of sharks,

my mind's racing because I
don't understand why mantas

would be in this hostile
environment to begin with.

What is it that they're
comingdown here to do?

Manta researcher
Andrea Marshall and her
team of specialists dive

into the sardine run to
unlock this mystery

on a first ever manta ray
expedition

to South Africa's wild coast.

The wild coast of South Africa,
stretches for 170 miles.

Here, the waters of the
Indianand the Atlantic converge,

forcing powerful waves
towardsthe shoreline.

Its savage winds and heavy
seashave claimed many ships.

There's a reason why they
call this the wild coast'.

It's incredibly hostile:
really cold waters,

incredibly turbulent.

I've been put into all kinds
ofdifferent environments but

this is by far the hardest
conditions

that I've ever worked in.

Andrea Marshall is one of
the world's leading experts

on manta rays.

Oceanic Mantas are among the
world's largest fish.

Andrea's research isprimarily
based in Mozambique

but today she's embarking
onher first manta ray expedition

across the border
to South Africa.

And it's one of her own
mantarays that's brought her here.

The very first manta that
I tagged made a beeline

down the coast from
Mozambique to South Africa

and it begged the question

where is this manta going?'

And for the first time
Irealized that they may not live

in Mozambique

where I've been studying
them for the past 15 years.

Mantas inhabit tropical
waters in every ocean

and are heavily fished for
their gill rakers,

which are used in
Chinese medicine.

Despite their size,
little isknown about their movements,

which makes them hard
to protect,

especially in
international waters.

Andrea is hoping to prove
thatthe mantas she studies

in Mozambique are migrating toSouth Africa.

She believes mantas may be
attending the sardine run,

a mass fish spawning event
onSouth Africa's wild coast.

But mantas eat plankton,
notfish, so the question is: why?

I couldn't wait to make
this sort of migration

of my own, to find out what
ishappening down at the sardinerun.

Are there mantas there?

What are they doing along
this coastline?

Andrea and her team
travelnearly 900 miles south

from Tofo in Mozambique
to Port St. Johns.

Known to divers as the
heart ofthe sardine run.

Though the forces that drive
theannual journey of the sardines

aren't completely understood,
it's believed that the fish

abandon colder waters off
the southern tip of Africa

and travel north in pursuit
of more favorable conditions.

For much of the year,
the warmAgulhas current sweeps

southwest, keeping
temperaturestoo high for the sardines.

But in winter, a corridor of
cooler water allows

the fish to comfortably move
up the coast.

As the sardines move north,
Andrea believes the mantas

in Mozambique are
migrating south.

It's June,
the start of winterin South Africa.

The cold water is beginning
tomove up the coast,

bringing with it, the sardines.

Millions of them, in
rippling masses,

that can stretch for
more than nine miles.

It's a migration that rivals
thejourney of the wildebeest

across the plains of the
African savannah.

Along the way, strong
currentspush plankton to the surface,

providing a steady source
offood for the migrating sardines.

As the fish converge on thesurface,
they make ideal targets

for hungry predators.

Super pods of dolphins,
sharks, birds and whales.

So essentially all of thesepredators
from all over SouthAfrica

descend upon this really
narrowstretch of coastline.

Swimming through this swirlof sharp teeth

are giant oceanic manta rays.

With a wingspan of 22 feet,

they're as wide as a pickup
truck is long.

But these passive filter
feeders are easy targets

in an area teeming with
top predators.

The giants are defenseless
against sharks.

Manta rays rely solely
on their speed,

and their flattened bodies
for protection.

A bite to the manta's flat,
large wings generally won't
be fatal.

To kill a ray, a shark must
through the central body

that contains its vital organs.

Manta rays are incredibly
fastthrough the water.

And can hit top speeds of
20 miles an hour,

to escape predators.

Manta rays have no
sharp teeth, no venom,

no defensive weapon to speak of.

Unlike their relatives,
the stingrays,

which have a protective
spine atthe base of their tail.

Mantas don't have a stinger
to fend off attackers.

They're really quite vulnerable.

Why they would come all this
wayand hang out in this area

when there's so many
predators, we have no idea.

And that's the question
that's driving us:

what are these manta rays
doing off this coastline?

I've assembled a team of
international scientists.

We've brought in Dr. FabriceJane
all the way from Australia

who's a telemetry
specialist on manta rays

and we're going to try and
deploy the first tags

in South African history.

Andrea hopes her satellitetags
and Fabrice's new cameratags

will provide some much
needed answers.

If they can fit a manta ray
with both tags,

they'll learn where
the ray is going,

And get a first-ever
look at what it's doing

when nobody's watching.

But first, they need to
analyze the manta track

that's brought them here
to the sardine run,

in the first place.

They hope that retracing the
steps of this manta ray

will help them find others.

So for the first part of
the track,

it spent quite a bit of
time in front of Tofo

where you were based.

Wow it really did.

Eventually it decided
totravel south and it went south

all along the coastline,
fairlyclose to the shelf edge again

and it ended up

in South Africa and it ended
up near Port St. Johns.

What are these animals
doing down here?

It's freezing and there's a
lot of sharks.

Yeah, I mean look,
thecontinental shelf seems to be

right up close to the coastline.

That's quite interesting; theremay
be some upwelling happening.

A lot of productivity being
brought up to the shelf

near the coastline.

It may be food-related,
but it may be related

to the sardine run as well.

You know a lot of food
scrapsin the water and so on.

I mean dolphins and whalesand
sharks all descending upon

this coastline, every year.

And so to have mantas here
inthe mix is just so exciting.

I can't wait to get
in the water.

I know, I can't wait to getin the water.

Tomorrow will be the
first ofmany grueling days

of field work, to uncover
why this manta ray migrated

to the sharkiest
coastline on earth.

t's going to be a really
challenging few weeks

because this is a really
wild part of the world,

in fact it's probably the
mostchallenging place

I've ever had to do research.

I've prepped my team.

I've told them that this is
notgoing to be a walk in the park

but I'm actually excited to
come out and do research

in places like this because
it is a challenge.

Day one of the expedition,

and the team faces
its first obstacle,

before they
even make it out to sea.

The pounding waves of
the wild coast limit

the launch of the boat
to just one spot.

Andrea and her team must
leavethrough Port St. John's

river mouth, and tackle
incoming waves head on.

We're waking up at 4 or 5
o'clock in the morning,

and it's bitterly cold.

The launches are extreme.

We're launching through thesemassive waves.

So you get soaking wet.

I mean it is such an
excitinglocation but obviously

it's not a very easy
locationto do any research.

The team eventually clearsthe breakers.

But the hardest part,
is yet to come.

You're freezing cold on theboat
in this wind looking formantas.

You have to get in this
freezing cold water

and you have to find it in
visibility that sometimes

is less than a meter

and you know there are sharkseverywhere.

I knew from the outset that
it was going to be

really difficult
in-water conditions.

So I really wanted to give
myself the best leg up

that we could possibly have.

And one of the most
importanttools in our arsenal

is having aerial support.

The fact that my husband's
apilot and we can fly the coast

and find the mantas from
the airis a huge blessing for us.

My role at the sardine
runis to fly in a plane

and to spot the animals
from the air.

It's very difficult: harsh
conditions, bad visibility,

big swell, everything.

So you can see way
better from the air

than in the water itself.

Plankton blooms cloud the water,

creating the poor
underwater visibility.

An aerial perspective
allowsJanneman to spot disturbances

on the surface caused
by swarming sardines,

and guide the divers
to the action.

Like the sardines,
mantas feed on plankton.

The hope is that finding
the sardines,

will lead the team
to the manta rays.

As millions of sardines
migrateup South Africa's east coast,

in their wake, a convoy of
predators trails behind.

In an army of sardines
thousands strong,

a single fish is much
harder to target.

The sardines move as one,
in aformation called a bait ball.

These bait balls can be huge.

They can be bigger than a
football field sometimes

and what happens is the
sardinescome up and they get pushed

to the surface by the predators.

It can be small fish like
tuna, or it can be dolphins

and as soon as they push
them out of the water

and they disturb that water
that's what I see.

Janneman has yet to
spot a manta,

but the seas below are
exploding with action.

Dolphins work as a team
to herd the sardines

into an even tighter formation,

increasing their odds
of catching a fish.

They surround the school and
use their fluke, or tail,

to drive any fish that
swimastray back to the formation.

Once a tightly concentrated
bait ball is formed,

the dolphins take turns hunting.

As each dolphin rockets
through the shoal,

the others stay close by to
herdthe fish back into the group.

Then, the dolphin pod
tightens the noose.

They force the sardines to
the surface,

eliminating a possible
escape route.

For the sardines, it goes
from bad to worse.

The feeding frenzy attracts
theocean's most-feared hunters:

Sharks.

A bronze whaler shark
arrives on the scene.

Unlike dolphins,
the sharks huntindependently.

The very first time I
jump inin the sardine run,

my mind is blown.

It's unlike any environment
I've ever worked in:

there's predators everywhere,
visibility's not good,

it's cold water, there's
birds all over the place

smashing in the ocean.

It's been two days,
and theteam has seen plenty of action

in the water.

That is awesome!

Whooo!

Look at that ball!

Go little fishies, go!

But so far, no manta rays.

I show up at the sardine
runand there's nothing there

and I thought what if
they don't come?'

There's so much pressure
as a field biologist.

You have such a narrow
windowof time to execute some

of this research.

I really want to protect thembut
in order to do that properly

we need to know
everything about them,

including where they go
when they leave Mozambique.

That's fundamentally
importantto their conservation

and that's what's driven me
all the way down

the coast to SouthAfrica
is to try and find out:

do they spend time along
this coastline?

What are they doing?

Actually, do they spend the
majority of their time

off this coastline?

You know, these are the
questions that are really

important to answer.

The manta ray population
backnorth in Mozambique

seems to be in sharp decline.

In the last 15 years, manta
sightings at Tofo beach,

where Andrea works, have
dropped by more than 80%.

Some rays are accidentally
tangled in gill nets

cast along the beach.

Others are targeted for
their gill rakers,

the filaments that help
manta rays filter feed.

Rakers are popular in
Chinese medicine,

and are in high demand on
the black market.

Knowing that we're runningout of time,

that these animals are
threatened with extinction,

that we have no idea
what's happening to them

along this coast,
whytheir numbers are plummeting,

and if we don't answer
these questions

then we're not going to be
able to help protect them.

The team's air-to-ground
search uncovers no mantas.

There's a tremendous amount
of internal pressure

as well as a biologist that says

we don't have the time
to screw this up'.

This is mission
critical, you know,

and we have to get this done.

Andrea and Fabrice revisit
the manta ray track.

They enlist the help of
oceanographer Lisa Holton

to interpret the data.

The team hopes that
anunderstanding of the topography

and ocean currents can provide
some much-needed clues

on the whereabouts of
these mantas

so Andrea and
Fabrice can tag them.

The interesting bit of the
track is really off

Port St. Johns there.

It did that circle pattern
off shore.

Whenever as an oceanographer
you see circles it points to aneddy

and it's very possible there
isan eddy around there.

An eddy is a circular
movement of water,

that counters
the general direction

of the ocean's current, to
create a whirlpool.

Eddies are common in the
ocean, and can range

from several inches to
hundredsof miles in diameter.

Their swirling motion
forces nutrients,

normally found in colder,
deeperwaters, to the surface.

Your manta probably came
downon the Agulhas Current, which is

the big, warm current that
comesdown the western coast.

The Angulhas is very
strong and fast.

It's about four centimeters
a second.

Okay.

Wow.

At the surface, which
is pretty speedy.

And when it comes down it
obviously creates a lot

of instabilities and that's
whatforms these circular motions or

meanders and all of these
thingscan lead to upwelling

and produce nutrients,

which drives productivity
and food for your mantas.

The possibility that the
mantas are drawn to feed

at a revolving eddy in the
oceancurrent is an important clue.

Manta rays feed almost
entirely on plankton.

Their favorite is zooplankton,

the tiny animals that float
in the current.

When plankton is evenly
distributed within

the water column,
a manta raywill feed mid-water,

by swimming with its giant
mouth wide open.

A specialized set of gills
outfitted with filters,

traps the plankton as the
water flows through.

When enough plankton is caught,
the manta ray closes its mouth,

and coughs the food into its
throat to swallow it.

An adult manta ray can weigh
as much as a car,

and can eat more than 60
poundsof plankton in a single day.

With a diet composed of
tiny organisms,

eating is a full-time
job forthis giant fish.

The manta ray will travel
milesacross the open ocean,

in search of dense
patches of plankton,

where it can feed
more efficiently.

Upwelling events provide thisopportunity.

Currents force plankton to thesurface,

where it collects
in large sheets:

an easy meal for the manta rays.

If Lisa and the team are
right, and the manta rays

are in fact migrating here
to feed on plankton.

Delivered to the coast
by the upwelling,

the rays should be easy to spot.

When these ocean giants
surface to feed,

they create large
turbulent wakes,

which can be
seen from great distances.

We've been at the
sardine run now,

on expedition in Port St.
Johnsfor the last three days

without seeing mantas at all

which is what we're here
to dosome research on,

I don't know why we're
not seeing any.

Andrea and Janneman
carefullyscan the water,

keeping an eye out

for manta rays feeding
at the surface.

Armed with a camera,

Andrea zooms in on
anypromising shadows in the water.

Finally she spots an oceanicmanta
ray and then another one.

Janneman sees a third ray,

but this one isn't what
they expected.

Stunned at what they
think they've seen,

Janneman spins the plane
aroundto get a second look.

What they've spotted is
a big surprise.

That was an epic flight.

I cannot believe
we found mantas.

After three solid days of
not seeing mantas we found,

two giant mantas and
incredibly, a reef manta.

Reef manta rays are
almost half the size

of giant oceanic mantas,
about 10 feet wide.

as the name suggests,

reef manta rays live on reefs,
along tropical coasts,

and oceanic islands.

It's believed they migrate
across their range

to exploit seasonal
resourcesand find mates.

The two are easy to tell apart.

A reef manta has a Y'
shaped pattern on the back,

and a spotted belly, the
Giant Manta has fewer spots

on its underside, and a T'
shaped pattern on its back.

The discovery of a reef
manta ray in these waters

is a huge coup for the team.

Reef manta rays move far
lessthan migratory oceanic rays

and likely are resident off
thispart of the South African coast.

This is the most southerly
distribution of reef mantas

in all of Africa.

Glad the mantas are here
andI'm just excited for the week

and hopefully we can
get the tags on.

Although the team has
located the rays,

there's still a lot
of work to be done.

Andrea brought her
satellite tags.

Which measure everything
from water temperature

to depth and pressure,

as well as tracking a
manta'swhereabouts via satellite.

In addition,
Fabrice hopes totest a brand-new technology

that will allow the team to see,
for the first time ever,

what a manta sees.

So the idea.

Wow!

That's amazing looking.

It's a bit of a contraption
but it's actually quite nice.

So the tag is pretty
much thislittle bullet there.

That's the camera.

The main thing is, it's got
a camera in the front,

which can film HD.

Then we've got a
pressure sensor,

light sensor,
temperature sensor.

So it's very similar to
those satellite tags

but in addition to that,
it has a camera

and it also has acceleration
in three dimensions.

Amazing.

How does it work?

So pretty much the way
we'vedesigned is that you just lodge

the camera in the slot
pretty much.

That orange thing is pretty
much the float.

So we've tried to streamline
itas much as possible so based

a bit on a remora design.

Fabrice's tag mimics theshape
and size of a remora fish.

Also known as suckerfish.

Remoras attach themselves tolarger hosts,
like manta rays,

for easy transit.

As the name suggests,
the suckerfish uses

its modified dorsal fin as
a suction cup to cling onto

its host for
long-distance voyages.

Similarly, Fabrice's tag
attachment

uses specialized suction cups,

modeled after the
remora's mouth.

I'm so impressed by that design.

It's, I cannot wait to get
it on a manta.

That's going to be so exciting.

Yeah look it's taken a few
years of development and, you
know,

ideas put together and all
ofthat so we're really hoping

that we get some success.

I love when we can makehistory
like this and, you know,

put something on that's,
you know, so wild and wacky

but is going to give us
some great information.

With their tags prepped,

the team heads out in
hopes ofputting the first-ever

camera tag on a manta ray.

This is the moment
they've been waiting for,

a chance to deploy the new tags.

Just right there, we can
see its back.

Manta as big as the boat.

This is it Fabrice,
make it happen.

There it's at the surface again.

Standby.

It's turning.

No we got it.

We got a visual.

It's coming right at us.

For Fabrice, he'd been
workingon this tag for two,
three years

and we have this really
narrow window of time

and so the pressure
is really on.

Straight ahead!

Swim!

I'm rooting from the boat,
you know,

as these guys are in the
waterswimming as hard as they can,

but the mantas stay
one step ahead of them.

Left!

Going to Fabrice!

Going towards Fabrice!

Oh there's the dorsal.

Oh, c'mon guys.

They just never let
them get close.

We had come so far and
the manta's right there

and they just seem to be a
bodylength in front of them.

Fabrice isn't able to deploy
his camera tag.

But the manta ray
is still nearby.

So now it's Andrea's turn.

She'll try to deploy one
of her satellite tags and,

like Fabrice, she must do
itwithout the help of scuba gear.

As I jump in the water it's
a really different situation

than I'm normally used
tobecause normally I'm on SCUBA.

At the sardine run, the manta
rays feed on the surface.

Free diving gives the team
thebest chance at tagging.

Foregoing the scuba gear,
allows the divers to act fast,

and swim fast.

As I hit the water I realize

I have only a few minutes
with this animal

and I have to do allthis
work on a single breath.

Straight ahead of you!

Left Andrea.

You're swimming as fast
as you possibly can

and then trying to hold
your breath.

And as I'm swimming
towards this manta.

I hardly have any breath
as itis and as I duck under

I have about 30 seconds
to get this tag on

and you just feel that pressure.

Against these odds, Andrea
manages to attach the tag.

Did you get it?

We got it!

Whoo-hoo!

Well done you guys!

Andrea carefully aimed her
pole spear toward the crease

of the manta ray's wing,

where it won't hurt,
or limit its mobility.

Even so, this type of tag
requires piercing the skin

of the animal.

Marine biologists worldwide

are looking for a
safer tagging method.

And Fabrice's non-invasivesuction
tags may be the answer,

if the team can find
a way to get close enough

to properly secure the
tag onto a manta.

The next few days produce
mixedresults for the team.

There are several more
manta sightings and Andrea

is able to deploy another
satellite tag.

The team will now be able

to track two manta rays'
whereabouts,

and hopefully uncover why
these gentle giants

are coming to some of the
sharkiest waters on earth.

But they're still no closer
to attaching Fabrice's

new camera tag.

He manages one close call

and the suction cupbriefly
sticks onto the manta,

but detaches as
the ray speeds off.

We weren't having luck withthe
suction cups the other day,

so Fabrice spent all night
kind of re-working it

so the camera has
like a fin clamp on it now,

which is amazing.

The whole idea is we're
goingto deploy that clamp

onto the dorsal fin.

The clamp's going to
stayattached for a couple of hours.

That sounds amazing!

All right I've got a manta.

It's swimming at the surface.

It sounds like Janneman
just found another manta,

which one are you going to try?

Are you going to try this
firstand then that one?

I'm going to go for this one.

All right let's give it a go.

Fabrice it's huge!

Stop!

Perfect go straight!

You guys swim!

Swim!

Coming straight for you!

But the manta turns upside
down, and ducks below Fabrice,

making a quick escape.

Was it a female?

Big beautiful giant,

we'll have to double checkbut
it's definitely interactive.

Very friendly, very relaxed.

Let's go again!

Thirty meters.

This time Andrea tries herluck
deploying one of Fabrice'stags.

Now that we had the first
attempt the manta knows

that we're after it.

It's not necessarily scared

but it's just cautious
as we approach it.

It wants to see what we are.

She comes within inches
of the ray.

But at the last second,
it flees.

Manta rays have good vision.

Their wide-set eyes
provide abroad field of view.

But they have a blind spot,
directly behind them.

An approach from the side,

will cause the ray to flip
its body upside-down,

so it can turn around
toevaluate any possible threat.

This technique gives
the manta a better view.

It also presents the largest
possible surface area

of its body to the
unknown object,

to dissuade potential
predators from attacking.

Once again, Andrea
approaches the manta,

this time from the rear.

She's careful to remain in
its blind spot.

To not spook the ray.

Janneman's yelling from the
air like "there's the manta".

You know, the people from
theboat are saying "swim faster"

but nobody knows what it
feelslike to be in the water

with that type of
pressure on you.

Straight ahead!

Five meters!

Look underwater!

And it's all riding on you
and on that moment.

The tag is on!

But not for long.

Ahh!

Shame man.

That was so exciting!

Ahh!

Science!

We followed this manta for ages.

It's at the surface, dorsal
fin right there,

managed to get it on.

I thought "It's done!" and
itswam away with speed

and it looks like the speed
of the manta's movements

kind of broke the tag apart
soit floated to the surface.

- It's really exciting to be ableto test tags for the first time.
- I love this kind of work.

It's basically like pushing
theenvelope on science, you know,

and the methodologies
andfiguring out how we can study

these animals in a new way.

They spend the next two
dayssearching for giant manta rays,

desperate to test the new
attachment.

What they find instead,
surprises them.

What's happening?

Baby manta.

Where?

80 meters, 11 o'clock.

I was absolutely shocked
the very first time

that we approached
with the boat.

It became clear to me
that this was a baby.

I see it!

There's the ripples on
the surface.

Very chilled.

Fab do you see it?

Was he feeding?

It's super, super small guys.

Let's try and approach
really gently.

It's just here, it's just here.

Alright, it's coming
towards the boat.

I think this might be
thesmallest manta I've ever seen.

Three o'clock guys.

Got a visual.

Oh my God, it's so small.

Oh c'mon this is the one.

This is the history right here.

It's gonna not just be the
first tag on ever like this

but it's going to be the
babiest manta ever.

The team gives the suctioncup
attachment another shot,

but the manta takes off.

Looks like they had a close one!

What happened, Fabrice?

It's a beautiful small
reef manta, female

and she's really tiny.

She's like one to one
point five meters.

And she's very relaxed
just feeding at the surface.

Very chilled.

So we tried to get really
closegently and then she dived down

and disappeared.

In the coming days, the
excitement continues.

Look at that!

That is amazing!

They find more baby mantas.

Oh wow, that is a
miniature manta, oh my,

that is a newborn manta.

It's a baby.

That one was born yesterday.

The team gets a second
chanceto tag a baby reef manta ray.

Turning towards you, 10 meters

Coming towards you, it's a
little bit on your left,

Ninety degrees right.

It's just there guys keep going!

Woohoo!

Wow!

Baby manta!

Breaching!

Amazing!

Once again, the suction
tagsjust don't seem to be sticking.

But these sightings alone,
excite the researchers.

Now to me that is so
shocking because at birth

these animals are very, very
small,

only about 1.5 meters, and
completely defenseless.

I would assume that a lot
of these baby mantas

would become shark bait.

But at the same time I mean
ifthis is a natural pupping ground

then we need to know about
itbecause that will be another

really important
part of the puzzle.

We very, very rarely see babymantas so,

again it was a shockto
be able to see not just one

but several of them
at the sardine run.

It's really telling you know.

It obviously shows that
babymantas are born in the vicinity.

It's unlikely that adult
reef mantas would come

to these shark-filled waters
specifically to give birth.

So the presence of
all the babies

implies there is a
residentpopulation of reef manta rays

along this coast,

the most southerly distribution
of reef mantas

known to science.

As the expedition continues,
theteam consistently finds mantas,

though only in specific
pockets of water.

They're eager to
find out why the rays

are favoring
these particular areas.

As research picks
up on the water,

Janneman faces
anunexpected problem in the air.

I started hearing a clicking
sound in my engine.

I knew something was funny.

I radioed the boats instantlyand
told them guys get ready'.

And that's when I
starteddescending without an engine,

so you're literally just like
drifting through the air

and there's that sweeping
sound of the wind.

Anything can happen while
you'rein the sky and for me

the scariest part of all this:

anything can happen
over the ocean.

So normal people fly over land.

If something happens they
canjust find a place to land

or a road.

In the ocean there's only
oneway and that's in the drink,

in the water.

I don't know what you call it, maybe luck,

but I made it back to the beach.

Janneman was able to land
unscathed,

but the same can't be said
for his plane.

He enlists the help of some
local kids to move the plane

closer to the mouth of a
riverflowing to the beach.

Push, push, push.

It's the only entry point
tothe beach from inland.

It'll be a few hours before
help arrives.

While Janneman deals with
recovering the plane,

the team must find new ways

to carry out their finaldays of research.

The winds have picked up,
andthe water's choppy.

Spotting animals from the
boatbecomes an even bigger challenge

now that they've lost their eyesin the sky.

So they turn their attention
ina slightly different direction,

trying to determine why the
mantas seem to be

favoring certain
pockets of water.

They enlist oceanographer
Lisa Holton to help.

She uses the coordinates
wheremanta rays have been spotted

so far as a guide.

And analyzes the water
in that specific area.

She has CTD machines

that measure salinity
and temperature,

so we thought why
not bring her out

and try to put some of these
machines down

so that we can capture this
information

and find out if there's
upwelling in these areas

and the mantas may
be specifically

using these areas to feed.

So where are the actual
sensorson this thing?

Ok so this one's temperature.

This is conductivity, which issalinity.

Right.

And that'll be depth.

Excellent.

It's actually pretty compact.

Yeah and this is batteries.

So strategically we just
dropped one in the morning

we should obviously
do it incrementally

throughout the day.

Yeah, it would be interestingto
see if the conditions change

throughout the day.

Temperature, salinity and
depth measurements will help
determine

if there's an upwelling,
bringing colder water,

rich with nutrients, up
to the surface.

These nutrients support the
growth of plankton,

which in turn provides food
for filter feeders,

like manta rays.

We just stopped the boat
because I can see

there's just substantial
amounts of zooplankton

at the surface.

This is exactly what mantas
love to eat.

It's actually, Lisa,
a greatplace probably to drop the CTD.

The team spends the day
taking measurements

in different locations
and at different depths

along the coast.

Just finished the very
last CTD drop.

It was a really long day on theboat today,

but what we did is we
actuallywent to all the different areas

where we had seen the mantas

and some of the areas where
weconsistently don't see mantas

and dropped: some inshore,
some offshore.

So hopefully we'll be able
to get some good data.

You off?

Yeah.

Awesome having you.

Let's get you out of here.

Big long drive eh?

The expedition comes to a
bitter-sweet end.

Glad you came buddy.

Thanks very much.

Fabrice and Andrea weren'table
to deploy the camera tags.

But they were able to prove
thatoceanic manta rays are routinely

here at the sardine run.

We managed to deploy the
first two satellite tags on
manta rays

in South African waters,
which is amazing.

Hopefully the data will
complement what we found out

from that Mozambique manta
that migrated here before.

The team also found several
baby reef manta rays,

suggesting there's a
residentpopulation of reef mantas

in these waters as well.

The most southerly populationof reef mantas

ever documented in Africa.

But while the expedition
has come to an end,

the analysis of data is
only just beginning.

Three months later,
some of theresults from the expedition

are finally ready for Andrea
to review.

When we tagged the animals

I think the assumption
on my part

was that we were going to
see tracks along the coast.

The track couldn't be
moreopposite to what I was expecting

which is that they kind of look
like they nipped inshore

to the Port St. Johns area
very quickly

and then almost as quicklythey
seem to have disappeared

straight off into,
the Indian Ocean.

The more we're learning
about these mantas

the more we're learning

that they're actually
an offshore species,

a species that actually,

spends a lot of time in
international waters,

waters that are not policed,

and that's going to
have huge implications

on their conservation
because these are the areas

where we have the majority
of our industrial fishing.

And even more to the point,

these are the areas where a
lotof illegal fishing is happening.

This information needs to get
togovernment on local levels

and regional areas so they
canexamine what these animals

are doing in their location
and figure out how

they're going to tackle
this conservation problem.

Although Andrea's
results confirmed

that oceanic manta rays do
attend the sardine run,

what they're doing there
remains a mystery.

I'm still baffled

by why they're choosing to
comeinto the Port St. Johns area

and that's one of the reasonsI
brought my friend Lisa out.

I thought maybe she could help,
you know shed some light on why

these mantas would be
choosingthis specific area and

unfortunately we weren't
ableto solve that mystery.

Lisa's CTD results
showed no indication

of a specific upwelling

that would suggest nutrients
being pumped into the coast.

If they're not there for
the plankton,

are they actually there
for the sardines?

This is the first hint thatperhaps
mantas would be moving

inshore to target something
like an anchovy ball

or a sardine ball

and so I think that's
going to be the thing

that takes me back there
becauseI want to solve this mystery.

You know it's probably one
of the toughest places

to research manta rays
that I've been to,

but you know this
is not the end.

We're not giving up.

Every year I promise myself
I'm not coming back.

This is too dangerous,
this istoo hard, this is too cold,

what am I doing spending
a lot of time here?

But a month later I book
for the next year

and we start it all over
againevery single time.

There's something about it
that's just addictive.

You know, you need to go
backand it's real exploration.

That place really needs help
andI think there's more to it

than people think and we want
tofind out what's going on there.

Solving this mystery could
help save the future of both
reef

and oceanic manta rays in
this part of the world.

♪