NARRATOR: Indonesia.
The crossroads of two mighty oceans.
Where the waters of the Indian and the Pacific converge...
powerful currents help feed the most vibrant coral reef system
on earth.
An explosion of plankton draws giants
from the depths of the ocean.
LEWIS: It's just incredible when you see a manta ray
sort of come out of the gloom.
They're just magnificent, beautiful creatures.
NARRATOR: A team of researchers has set out to study
and save these gentle giants with secret lives.
(♪♪♪)
The giant manta ray,
the largest ray on the planet.
Nearly as wide as a tennis court,
as heavy as a car.
One of the world's largest fish
fueled by some of the ocean's smallest creatures,
plankton.
The tiny plants and animals that drift through ocean currents.
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The giant manta ray is one of the most intelligent fish
in the ocean
but little is known about them.
Manta rays were first scientifically sighted in 1798.
It wasn't until 2009, that researchers discovered
there isn't just one species of manta ray,
there are two -
the giant oceanic manta ray,
and the slightly smaller reef manta ray.
Both species thrive here in Indonesia's pristine waters.
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On the edge of the Pacific and Indian oceans
lies an underwater paradise.
Raja Ampat.
A coral garden, packed with mesmerizing marine life,
and one of the only places on earth
where both species of manta ray co-exist.
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Raja Ampat is located in the remote eastern corner
of the Indonesian archipelago
more than 1,000 miles south of the Philippines.
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It sits just below the equator
along the southern lip of the "ring of fire",
a belt of raging volcanoes
and tectonic plates that rims the Pacific Ocean.
The reefs of Raja Ampat are a hotbed of activity.
Plunging walls,
and soaring seamounts
encrusted with more than 600 species of coral
erupt with life.
75% of the world's coral species thrive here.
And more than 1,700 species of reef fish
call these corals home.
Raja Ampat means four kings in Bahasa,
the official language of Indonesia.
The name comes from a local myth of a woman who found seven eggs.
From these eggs came four kings
who occupied four of the archipelago's largest islands
known today as Raja Ampat.
Underwater,
the reigning kings of Raja Ampat are the manta rays.
To preserve the thriving population here
Indonesia established a manta ray sanctuary in 2014.
Stretching across two million square miles of ocean.
At nearly twice the size of India,
it is the largest manta ray sanctuary on earth.
ERDMAN: Fortunately there's an awakening,
which is happening now in Indonesia.
It's been led I think by manta rays that's been kind of
because of the tourism value of manta rays.
And so we've seen really an awakening
about the need for conservation.
NARRATOR: Dr. Mark Erdmann and the team at Conservation International
want to protect these charismatic creatures.
Mark has logged over 10,000 dives
throughout Indonesia
and discovered more than 100 new species of reef fish.
He now uses his knowledge of these waters
to track Indonesia's manta ray population.
ERDMAN: From our photo ID database that we have of the manta rays,
there's over 400 individuals of the reef manta rays
that we've recorded.
And something just under 200 individuals
of the oceanic manta ray here.
LEWIS: We think this is quite a big population of manta rays
that we have here in Raja Ampat.
It's a really, really unique place for manta rays
and really important that we protect it.
NARRATOR: Sarah Lewis has worked with Conservation International
and Manta Trust,
a UK based charity that funds manta ray research since 2010.
She and Mark are using a database of photos
to help track the populations of mantas here in Raja Ampat
and throughout Indonesia.
LEWIS: We have a lot of individuals to ID in this population,
which is very exciting.
NARRATOR: Raja Ampat's manta ray population
could be as high as 3,000.
So far, Sarah has identified just 600.
The team still has a lot of work ahead of it.
And Indonesia's powerful currents don't make it easy.
The Indonesian archipelago is bound by two great oceans.
Strong easterly winds lift the waters of the Pacific
one foot higher than the neighboring Indian ocean
pushing water through the islands
and creating some of the strongest currents on earth.
For the tenants of the reef,
these currents present both rigors and rewards.
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For those firmly anchored such as these soft corals
the flow of water brings a steady stream of food.
Others must fight to keep from being swept away.
On the reef, shelter comes in all shapes and sizes.
Crustaceans tuck into nooks and crannies in the coral.
Smaller reef fish sway side to side
beneath the canopy.
Bullied by the current.
Larger fish duck behind the plunging walls and seamounts.
For researchers,
currents are one of the most underestimated and overbearing
of all obstacles.
Water is 800 times more dense than air
creating strong resistance.
Swimming in powerful currents
is like walking through a storm-level wind.
A current of 2 knots is strong enough
to sweep a diver out to sea.
Indonesia's currents can reach up to eight knots
creating a challenge for anyone
trying to observe the undersea creatures.
LIM: Assuming that the current is moving in the regular fashion
and not up or down,
most of us divers we tend to hook in with a reef hook
and stay in position.
NARRATOR: Reef hooking allows divers to stay put
without exerting any energy.
Divers use a metal hook attached to a rope
to secure themselves to the reef.
LIM: And when the current is raging,
the sharks and mantas will generally come closer to you.
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So, if you're lucky they could come by
and hover over you in the current.
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NARRATOR: But reef hooking is not an option for Mark and Sarah.
They must be mobile
to locate and tag as many manta rays as possible.
Mark and Sarah leave a remote camera on the reef
for an extra pair of eyes.
(♪♪♪)
Meanwhile, their colleagues Abam and Abdi
patrol a tried-and-true manta site.
In the last year, their tracking data has shown
that this site is one of the most frequently visited
in Raja Ampat.
Abam assembles a pole spear
so he can get close enough to attach the tracker.
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But there are no mantas in sight.
SIIANIPAR: We wanted to spread around our tags
giving more numbers out there and see what happens
and what we can capture from the behavior of these mantas.
NARRATOR: They're hoping that if they tag more mantas
they can learn what draws them to this place
and where they come from.
But the visibility is poor.
And the currents are strong.
Their best bet is to stay put
and wait for the mantas to come to them.
Mark and Sarah use a motorized scooter
to move from one site to another.
(♪♪♪)
They scour the reef,
but after several dives,
and hours of fighting the current
the team comes up empty handed.
LEWIS: Studying any wild animal,
we have challenges with our research.
Even though we have a really abundant population
of manta rays here in Raja Ampat.
Sometimes we turn up in the right season,
the high season for manta rays,
the sites where we know they aggregate regularly
and they're just not there.
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NARRATOR: But more shocking than what the divers didn't see underwater
is what their remote camera did.
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ERDMAN: We're a bit dumbfounded actually.
We had mantas about every 5 minutes
showing up in the frames.
Unfortunately,
quite a few of them were just a wing or a head.
Not a lot of belly shots
but none the less we have definite proof
that there were mantas there all the time.
And perhaps most exciting we got a manta birostris,
the oceanic manta,
which up until this time has never been recorded
from Northern Raja Ampat
so we're delighted with that, that's a big find actually.
NARRATOR: It's a big find
because typically oceanic mantas and reef mantas
aren't seen in the same area, let alone on the same reef.
ERDMAN: As a general matter of course around the world,
there's very few places
where you get both reef and oceanic mantas together.
Raja Ampat is one of those few places where you do see it,
but for the most part they still segregate.
NARRATOR: Both species live their lives out in the open ocean
visiting reefs to feed and to be cleaned.
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Creatures of all shapes and sizes stop in for a tune-up
at the ocean's most efficient body shop.
Smaller reef fish like these cleaner wrasse
are specialists at removing parasites and dead skin
from larger fish.
Butterfly fish specialize in repairing bite wounds.
Cleaner shrimp tend to concentrate on the mouth.
A manta ray comes in for a cleaning,
hovering almost motionless over the reef.
A host of cleaner fish greets the long-distance traveller.
Gills flared, mouth open,
and wings spread wide,
the manta ray advertises the areas that need detailing.
The T-shaped pattern on its back,
and fewer black spots on the belly
indicate this is an oceanic manta ray.
A reef manta ray has far more spots on its underside,
and a Y-shaped pattern on its back.
Despite these differences, for years,
these two distinct species were thought to be the same.
Largely because they were so seldom seen side by side.
Until now.
ERDMAN: They have their own separate types of cleaning stations.
This is a case where you've got the both species
using the same cleaning station.
That was something we've never seen before,
we've only seen reef mantas
over the last 15 years of diving on that site.
And it really begs the question of how much do we not see
when we're down as bubble maker, divers.
(♪♪♪)
NARRATOR: When the team isn't around to monitor the mantas,
a series of acoustic stations listen in on their behalf.
These stations sit along the ocean floor
and receive pings from any tagged manta ray
that comes within a half-mile radius.
Every tag transmits a unique signal
that's recorded by the receiver.
A network of these listening stations
tracks how long a manta ray spends at each site
and where it travels.
The day is coming to an end
but the team still has work to do.
(♪♪♪)
Mark and his dive partner Eddie
manage to locate the listening station.
It's a simple but effective set-up.
A rope is chained to a sturdy piece of coral
on the ocean floor.
The receiver is attached to the rope
to detect any tagged mantas that pass by.
Buoys keep the top of the rope afloat.
Eddie heads up to the boat to download the data,
while Mark stays behind
to clean barnacles off the listening station.
The receiver is sealed with tape to keep it clean
and prevent malfunctions.
But when Abam downloads the data the results surprise him.
There's nothing there.
After almost three years.
The tags on the mantas are no longer working.
With the old tags now out of commission,
the pressure's on tomorrow
to tag as many new mantas as possible.
As the morning sun pierces through the surface,
the underwater world ignites
in a kaleidoscope of shapes and colors.
Smaller fish swim to the surface
to feast on the plankton
stirred up by the unruly currents.
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A tornado of tiny bait fish whips through the water.
They came here to eat plankton.
A shoal of pygmy devil rays, cousins of the manta ray,
pursues the bait fish.
(♪♪♪)
It's one of nature's most elegant high-speed chases.
The devil ray is one of the deepest, fastest divers
in the ocean.
It can descend more than a mile.
And swim at speeds of up to 13 miles an hour,
nearly three times faster
than an Olympic gold medalist swimmer.
The bait fish defend themselves by joining forces.
An army, thousands strong, moves as one large organism:
a ploy to confuse the hungry predators.
It's hard to pick out a single fish
within this silvery mass.
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Several fall out of line,
and the devil ray zeroes in on its target.
Devil rays are also known for their aerial theatrics.
Like acrobats,
they launch themselves out of the water
then twist and turn through the air.
No one knows for sure why they do this.
It may be a courtship or mating ritual.
Another theory is that devil rays breach
to rid themselves of parasites
that may be shed when the ray smacks back onto the water,
or, they may simply be trying to escape a predator.
Manta rays are also known as devil rays
thanks to the pair of horn-like fins
extending from their mouths.
While feeding,
the manta's fins unroll to direct plankton into its mouth.
After dinner, the fins neatly roll back up once again.
Manta rays are filter feeders.
Most often, they are seen feeding on the surface
where plankton is abundant.
Their mouths are wide enough for an adult human to fit inside.
But the manta's throat is no larger than a human fist
restricting its diet to tiny plankton.
When there's no plankton floating on the surface
manta rays seek it out in other ways.
These manta rays twirl through the water column
performing barrel rolls for hours.
This graceful underwater ballet
is actually a sophisticated foraging technique
designed to clear a densely concentrated patch of plankton.
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Both the surface and mid-water feeding methods
require specialized filaments called gill rakers
that filter food.
Plankton-filled water enters the manta's throat
and is pushed through the gill rakers.
The water comes out through gill slits on its belly
while the plankton is trapped inside.
Fisheries target mantas for these gills.
Rakers are used in Chinese medicine.
And are thought to cure everything from cancer
to the common cold
though there is no scientific proof.
Manta rays are listed as vulnerable to extinction
due to reckless overfishing.
For decades,
Indonesia has been one of the world's largest exporters
of shark and ray parts.
So the study at Raja Ampat is key to manta conservation.
If they can understand
where Indonesia's manta rays spend most of their time,
they can better decide
which parts of the huge ocean territory to monitor.
Patrol boats are assigned to frequently visited manta sites
to ensure illegal fishing boats stay away.
But if they don't know where the manta rays are
they can't protect them.
The discovery last night
that the batteries on the old tags
are beginning to die
means Sarah and Mark urgently need to tag new mantas
to continue the study.
LEWIS: We work together with a lot of this research
and specifically with the tagging
it's really important that we have at least two of us
to do this tagging process,
cause it's important
that we get the photo ID of the manta before we tag it.
NARRATOR: They'll use the photos to keep track of which mantas they tag.
If they manage to tag any at all.
The water is clouded with plankton
which increases the chance
that there will be mantas on the reef.
But decreases Mark and Sarah's ability to see them.
Visibility is less than 30 feet.
Even if the mantas are here,
Mark and Sarah might not see them.
Through the cloud, Sarah spots a moving shape.
LEWIS: Every single individual manta ray
has a unique pattern of spots on their underside,
and these act kind of like a human fingerprint.
So we can use these spot patterns
to actually identify individual mantas.
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NARRATOR: She positions herself beneath its belly for the perfect shot.
(♪♪♪)
LEWIS: And we just aim to try and photograph the bellies,
this spot pattern.
And during this process
we're also observing things like pregnancies,
reserving the sex of the manta, so whether it's male or female,
whether it has any injuries or mating scars
and what sort of behavior it's doing.
NARRATOR: This is a male reef manta ray.
Mark approaches cautiously.
Careful not to spook him.
Tagging requires focus and precision.
He has to aim the pole spear at a small area
in the crease of the wing
where it won't hurt the manta or limit its mobility.
Success!
With one manta tagged,
the team soon spots a second chance.
(♪♪♪)
Sarah tucks beneath to get a photo ID.
Mark waits for his signal then edges forward.
Another tag is in.
LEWIS: These tags give us very different
sort of insights into the manta ray's habitat use
and movement patterns.
We're getting a much better idea of how they're actually moving
between specific sites
and how long they're actually using these sites
and how important they are for them.
NARRATOR: The quick jab feels like being poked
with a vaccination needle.
But a little discomfort now will save this species later.
LEWIS: So this is really important data for us.
And it also means that we are better understanding
which sites are most critical for further protection
and further conservation efforts.
NARRATOR: After a successful day,
Sarah is eager to upload her photos.
LEWIS: Every time we get a new photo
we can then compare that with our database
of already identified individuals
to see if it's a new one
or if it's one that we've already sighted before.
We actually recorded eight new individual mantas,
which is fantastic and adds to our database.
Over time we can actually make estimates of population size.
So if we continually identify individuals from a population,
once we reach a stage
where we're getting mostly re-sighted mantas
we can then start to make an estimate
of how big that population is.
So far altogether in Raja Ampat
we have almost 400 individuals identified.
NARRATOR: With an estimated population of nearly 3,000 mantas
there is still a lot of work to be done.
As night sets in, the team sets out.
Wayag Island.
More than 350,000 acres of lush atolls,
and vibrant corals.
Limestone islands rise from the water
like mushrooms sprouting in the sea.
Green jungle blankets the islands.
Pristine beaches skirt the coast.
The crystal-clear waters of Wayag
offer a window into an underwater world
that is equally enchanting.
Wayag Lagoon is the first manta ray nursery
discovered in Southeast Asia,
a place with the potential to answer
two of the most important questions about manta rays:
where and how they give birth.
Manta rays are ovoviviparous.
They produce eggs that hatch within their body
so the young are born alive.
But a manta birth has never been documented in the wild.
It is assumed that a healthy mother
gives birth to just one pup every 2 to 5 years
throughout her lifetime which is thought to be 40 years.
Most females don't reach sexual maturity
until they're 10 years old.
Pups can weigh up to 25 pounds,
and grow to 5 feet in length.
The pup's fins stay curled up while they're inside the mother.
Once born, the fins stretch out,
and the pup intuitively starts to swim.
Mark and his team discovered Wayag's nursery
just one year ago.
After successfully tagging juvenile manta rays
in these waters.
But many questions remain unanswered.
Mark isn't sure whether females are giving birth in the lagoon
or whether the juveniles have somehow found their way here.
He wants to tag more juveniles
or a pregnant manta ray to find out.
It's rising tide
and the team suspects manta rays will be feeding on the surface.
For the first time,
they will use a drone to survey the area more efficiently.
ERDMAN: So we've got the drone hovering right over the cleaning station
that we found
and just hoping that we're going to see
one of the baby mantas come swimming along right there.
LEWIS: Is it moving?
It does.
Oh my gosh it really does.
ERDMAN: So we're not 100% sure,
but we have what looks like a manta right up on the surface,
its got a lot of glare
so its quite difficult with the overhead sun
but it looks like a manta
so I think we are going to run over there and check it out.
LEWIS: Here we've got a little baby juvenile reef manta Ray,
and we've just discovered this morning
that this site right here is actually a cleaning station,
and we've seen him out a couple of times cleaning right here,
so we're going to get Ronald in
to try to get an acoustic tag on this little baby.
NARRATOR: Ronald is a local diver.
He's worked with Conservation International
for the past decade.
And has been diving here even longer.
LEWIS: What we found with these babies in this lagoon is that
most of them are quite skittish,
a little bit scared of people
but they also tend to be a little bit curious at the same time.
NARRATOR: Ronald slowly approaches the juvenile manta
but his presence isn't well received.
ERDMAN: It was in curious mode
but it very quickly switched to skittish mode and shied away.
LEWIS:
ERDMAN: It's unfortunate
but that's just kind of the game here with the little ones.
NARRATOR: With the juvenile slipping away,
and no pregnant manta rays in sight.
This time, the team must leave Wayag's nursery
with their questions unanswered.
But over the next few days,
the team identifies seven more new individuals,
adding to their growing database of 600.
It's a great start
but there is still a long way to go.
LIM: We reckon that there's probably at least
two or three times that amount in the total population.
NARRATOR: Mark uses the last few dives on this mission
to collect genetic samples.
He wants to know if manta rays in Raja Ampat
are mating with the populations from surrounding islands.
Mark uses the probe attached to his tagging pole
to collect a tissue sample.
And stows it away in a vial for safekeeping
until he's back on dry land.
These genetic samples will reveal
whether the mantas of Raja Ampat
have been breeding with more distant populations
in the last three to five generations.
Knowing whether there is a genetic connection
is critical to their conservation.
If there is none,
it would mean that one population
can't replenish the other.
And these manta rays will require far more protection
than previously thought.
Genetics also provide clues
about how these gentle giants evolved.
Sharks have been swimming in our oceans
for more than 400 million years.
(♪♪♪)
Scientists believe rays originated from sharks
more than 150 million years ago.
(♪♪♪)
They evolved to adapt to life on the seafloor.
Primitive rays are thought to resemble
the present-day stingray.
They swam using wave-like motions
and were armed with a stinger on the tail for defense.
Modern stingrays have a spine in their tail,
serrated with sharp edges.
Many species also have venom
which they deliver through their tail.
Manta rays, as we know them today,
appeared about 5 million years ago.
A subtle bump on the tail of the oceanic manta
serves as a reminder of a time in evolution
when the mantas lost their sting.
Both manta ray species
can be either one of two color patterns
called color morphs.
One is all black.
The other, called a chevron,
has a white underside and black back.
Black morph manta rays have a recessive gene.
And typically make up only 25% of the total population.
In the Maldives,
generally considered to be a mecca for manta ray sightings,
no black manta ray has been identified
in its estimated population of 5,000.
Sarah and Mark have spotted 10 on this dive alone.
Back on the boat,
Sarah's newly identified manta rays support a theory
that has implications for all mantas.
LEWIS: We've added some new individuals to our database
and quite a few black morph mantas.
And this pie chart here is showing the color morph ratio.
So we've got 63% chevron mantas and 37% black mantas.
Why do we here in Raja Ampat
have such a high number of black color morph manta rays?
One of the theories is that this area,
this region of the world
is perhaps the center of evolution for manta rays
and that as the populations,
the mantas spread globally through time
that black morph just got phased out.
But still here in the heart
perhaps where manta rays evolved from
we still have that relatively high proportion
of black manta rays.
NARRATOR: Could Raja Ampat be the birthplace
of the black morph manta ray?
Or is this black manta population growth
actually a cause for concern?
Chevron mantas have what's called counter shading,
whether looking down against the inky black ocean bottom
or up against the white sky,
the chevron manta stays well camouflaged
to evade predators.
From below, the dark belly of the black manta ray
stands out against the light sky.
Making it an easy target for sharks,
the natural predators of manta rays.
But if they are more vulnerable to predators,
why are Indonesia's black manta rays thriving?
ERDMAN: The last 30-plus years,
Indonesia has been the world's largest shark and ray fishery
that they've been exporting more fins
and more bits and body parts of sharks and rays
than any other country on the planet by far.
That's had an impact,
a serious toll on the populations here
to the point where it's quite difficult
to go anywhere in Indonesia and see large sharks anymore,
they're pretty much gone.
NARRATOR: It is possible
that the black manta ray population is thriving
because the low population of sharks
means there are no predators to eat them.
(♪♪♪)
Indonesia's waters are now a protected marine area,
declared a no-fish zone for both sharks and manta rays.
(♪♪♪)
ERDMAN: We're getting there, it's a slow process
and to be sure there's been a major impact
I've been watching their populations recover and rebound
which is something which is really reason for hope
I would say.
SIANIPAR: The manta ray is so fascinating for me,
in their gentle way of moving
and they're actually really graceful animals.
NARRATOR: They're making progress,
but Mark and his team know there's still a long road ahead.
LEWIS: It's a really, really unique place for manta rays
and really important that we protect it.
(♪♪♪)
NARRATOR: From the fight to save these beautiful rays
to the discovery of ground-breaking revelations
about their secret lives.
Every dive at Raja Ampat
is a chance to learn more about the gentle giants
of Indonesia's untamed seas.
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