Original subtitles

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.

♪