Original subtitles

(gentle piano music)

- [Narrator] It covers 1/3 of the world's surface.

(inspiring instrumental music)

Ringed by fire.

Constantly reshaped

by the almighty clash of Earth's tectonic plates.

Creating lifeforms that, in turn,

become the architects of underwater empires.

Here the world's most primitive life forms

have outlived dinosaurs,

(whale bellowing)

and found astonishing ways

to adapt and survive

in one of the most competitive environments on the planet.

This is "The Wildest Pacific."

(gentle instrumental music)

The Pacific Ocean spans more

than 155 million square kilometers.

Its depths are less mapped

than the surface of Mars.

As we forge further into the underwater frontier,

numbering species are being uncovered

at a rate of nearly 2,000 each year.

The Pacific Ocean's terrains

are as varied as the land mirrored above.

From hulking sea mounts,

island atolls and lagoons,

to a monumental network of barrier reef

so long it can be seen from space.

The complex ecosystems of reefs

are the lifeblood of the Pacific.

One of the most important reef areas

is known as The Coral Triangle.

This small western corner of the Pacific

has scientists enthralled.

Below the water line,

a vast empire of coral reefs

has flourished from Indonesia,

north to the Philippines,

and west to the Solomon Islands.

This area packs in 3/4 of the planet's coral species

and is home to the world's largest

and smallest fish.

Like an underwater Amazon,

the coral triangle has the highest concentration

of marine biodiversity on the planet.

There are single reefs

that contain more species

than the entire Caribbean.

Here major ocean currents converge,

allowing species to intermingle.

Millennia of stable temperature

have given evolution time to do

its astonishing work.

(lava erupting)

The triangle is flanked by volcanic activity,

sandy beaches, and the world's

densest concentration of mangrove forests.

This range of topography in such a small area

has forced nature's hand

into specialized and curious adaptations.

Reefs flourish on submerged continental shelves,

on remnants of collapsed volcanoes,

or take hold on new sea mounts

rising up to meet the surface.

Over time, a reef develops zones

with varying currents, temperature, and structure.

Like rainforests on land,

coral reefs form huge, complex ecosystems

spanning hundreds of kilometers.

Each habitat hothouses its own variations of life.

From algae to crustaceans.

The smallest fish to apex predators.

Each tier of the food chain

supports the one above

and those at the top

keep populations in check.

It's an intricate dance

that has surged and subsided time and time again

for some 400 million years.

Modern reefs have risen

in the evolutionary blink of an eye

as sea levels for the past 10,000 years or so

have remained somewhat stable.

These immense underwater empires

are engineered from the tiniest of building blocks.

Coral.

Often thought of as a plant or rocklike mineral,

its neither.

A coral polyp is an animal,

a tiny carnivore just millimeters wide

feeding on passing zooplankton.

Little more than a mouth encircled

by stinging tentacles.

Coral does, however, have vegetable and mineral qualities.

Polyps themselves are clear.

A reef's striking color

comes from an even tinier organism within.

Algae called zooxanthellae.

Like terrestrial plants,

the algae photosynthesizes,

converting sunlight to energy.

Hard corals build limestone exoskeletons.

New polyps grow in the remnants

of the forebearers,

creating the structural framework of a reef city.

Hundreds of millions of years ago

coral cousins broke free to become swimmers.

Today seen as jellyfish.

An evolutionary explosion

took place in the seas.

Swimmers became walkers.

Sea life adapted to poorly oxygenated waters

with tubes and gills.

The first vertebrates appeared as bony fish.

Then amphibians, reptiles, and animals graduated on land.

Occasionally, taking an evolutionary U-turn

and returning to the sea.

(whale bellowing)

(bright music)

The reef itself is engineered,

not only by the living coral,

but by the animals around it.

From drifting algae and plankton

up to the apex hunters,

is one of the most complex

and delicately balanced ecosystems on Earth.

This titan triggerfish

is one the reef's hardest workers.

It has strong, rounded teeth

designed to crunch into coral walls and seabeds

in search of tiny crabs and molluscs.

The titan's mouth is so strong,

it's able to life large lumps of coral and rock

to uncover the best of the reef's hidden smorgasbord.

An intelligent fish,

the titan will spit water jets to uncover food.

Today this trigger has an unearthed a clam.

The shell is too tough to crack

even for a titan.

But this is one of the few tool using fish.

The titan drops the clam onto the seabed

in an effort to crack it open.

This trigger fish hasn't quite found the right tools today.

The sand here is too soft.

The clam's hard casing remains unbreached.

Reef builders like titans and parrotfish

aren't just a part of this environment.

They help shape it.

With formidable teeth fused into beaks,

they gnaw into the limestone coral

to reach the algae within.

(bright instrumental music)

This fish excrete the hard parts they don't digest

as calcium carbonate, or sand.

A single fish can create up to 90 kilograms of sand

every year this way.

Nearly every animal on the reef

contributes in some manner.

Shells, carapaces, bony skeletons,

all break down into tiny mineral fragments.

Their remains line beaches,

form islands,

line bays and burrows

of new lives just beginning.

The sand surrounding a reef

is made up of its last tiny remnants.

Over time, it builds up

and births new kingdoms.

Between reef and land is the inshore zone.

These areas are protected from incoming waves

but the shallows are exposed to harsh elements,

lower oxygen levels, and UV rays.

Only the hardiest of corals survive here.

Dense boulder and brain corals dominate.

There's enough gentle tidal flow

for nutrients to pass through

and protection from strong currents and waves.

Inshore animals can maneuver comfortably

and develop ingenious methods to do so.

Boulder corals grow at a rate

of just three centimeters a year.

Some are estimated to be over 1,000 years old.

(gentle instrumental music)

A master of the boulder domain

emerges from its coral lair to begin dawn patrol.

While most octopuses prefer to hunt at night,

the day octopus takes advantage

of the less competitive sunlight hours.

This boldness is backed

with exceptional camouflage skills.

The day octopus can change body color

in just 3/10 of a second.

A sophisticated network

of pigmented chromatophore organs in its skin

allows it to not only change color

but its entire texture.

Every second the day octopus

reassess where it is

and where it wants to go

and dresses appropriately to hide

or to hunt.

This hunting technique

is an all in approach.

Try everything at once

and see what morsels the reef gives up.

Boulder corals are a haven

for small fish and crabs.

Staples of the octopus diet.

It completely envelopes a small coral head

and employs a net fishing technique.

(dramatic instrumental music)

The octopus sucks sea water

into the webbing between each tentacle

and blasts it out,

hoping the force will flush out

any hidden treats.

Nearly 2/3 of this octopuses neurons

are located in its arms.

So they can work independently from the brain.

This makes it the ultimate smart mover.

It can apply several hunting techniques at once.

Using its arm to thoroughly explore nearby crevices

at the same time it's flushing out

an entire coral head.

Apart from a centralized feeding beak within its head,

the day octopus is boneless.

Allowing it to squeeze into almost any coral cavity.

(soft instrumental music)

Its eyes have sensory receptors

to keep vision oriented on the move.

Like an inbuilt stabilizer,

they'll see the same view

even as they flip upside down

and move quickly.

Which is useful when under attack

by damselfish.

(dramatic instrumental music)

Damselfish are perennials of the reef.

There are nearly 250 species

of these small, fork-tailed fish

and most of those live in the Indo-Pacific.

Despite their size of less than 15 centimeters,

damsels are highly territorial.

They won't hesitate to take on

a much larger octopus.

These fish are dedicated farmers.

They tend a small algal patch

which provides food.

They also have egg laying zones

within male territories.

The males will guard

the clutch of fertilized eggs ferociously.

When intruders enter their zone,

damselfish release a chemical alarm

into the water.

Other species join the attack on the octopus.

For this day octopus,

ambush hunting can become a little difficult

when shadowed by an agitated amassing school.

Some mornings it proves easier

to abandon the hunt

and go back to bed.

(soft instrumental music)

Shoals of fish begin to thin out

as the reef outskirts give way

to undersea sand beds.

The corridors between reefs

can feel like abandoned hallways.

Beyond the beach and boulder gardens,

protected in sheltered bays,

are expanses of sandy sea floor.

Vast tracks without protective cover

are a high risk area

for animals to venture into.

However, these seemingly deserted

underwater expanses

are teeming with life.

In fact, the sea floor

supports more species

than anywhere else in the reef ecosystem.

The bottom dwellers and diggers,

crabs, worms, and shellfish,

all looking for a life

away from the hungry mouths

of a crowded reef.

Reef rubble rolls down and gathers

at the edges of the long flats.

It has just enough nooks and crannies

to hold the interest

of one of the Pacific's most extraordinary crustaceans.

The brilliantly hued peacock mantis shrimp

digs burrows in the sand at the reef's edge.

(dramatic instrumental music)

From here it ventures out to hunt.

Despite its size of just a hand span or two,

this mantis shrimp has developed

exceptional hunting apparatus.

It has one of the most complex sight systems

in the animal kingdom.

Each eye can contain millions

of light sensitive cells

that pick up more wave lengths of color than mammals,

10 times more than humans.

They can even see ultraviolet light.

The peacock mantis shrimp's eyes

are able to work independently

to scan for food

or zero in on a target.

Folded up underneath its body

are these oversized claws,

modified into clubs.

The clubs are covered in a thin layer

of crystalline hydroxy appetite.

A coating that makes the clubs

much harder than the rest of the flexible exoskeleton.

These hammers can snap out with more speed

than a 22 caliber bullet.

Enough to shatter the hard shells

of marine molluscs and crabs.

It's the fastest punch in the animal kingdom.

While this formidable mini predator

boasts one of the strongest punches on the planet,

most marine floor dwellers

rely on another time honored technique to survive.

They hide.

(playful instrumental music)

For some, it's simply a matter

of replicating the sea floor as much as possible.

Others become expert burrowers.

Like gobies.

They're one of the largest marine families.

Estimated at more than 2,000 species and counting.

Many of those,

like the rare blue-barred ribbon goby,

are only found in the Coral Triangle.

Most gobies have developed fused pectoral fins

to help cling to coral rubble and rock.

These crab-eyed gobies

use their modified fins

to dig and fan at the soft sand.

Crab eyes form monogamous pair bonds.

They quickly dedicate their partnerships

to round the clock housework.

Their brooding burrows

can tunnel more than half a meter down.

If they can't hide quickly enough,

the twin spots on their fins

might be mistaken for the eyes of a crab in the shadows.

When the time comes for the female to lay her eggs,

the male will be the one to tend to them

in the burrow below.

The female may even seal up the entrance

with the male inside.

Until then, the sand is soft

and the tunnel keeps collapsing.

Home maintenance is constant.

The jawfish is a close relative of the goby

and is equally small

at just 12 centimeters long.

It's evolved earth moving equipment of its own.

Incredibly strong mandibles to scoop out its den.

Jawfish have learned they can stabilize

the soft entrance by lining it with shell and rock

which means less upkeep.

And to shut out unwelcome night visitors,

they'll seal the entrance for a restful sleep.

(gentle instrumental music)

Eels are the dedicated homebodies

of the suburban reef flats.

Fields of spotted garden eels

can be found along Indo-Pacific floors.

They'll burrow into the seabed

as soon as they're big enough

to make decent headway

or tailway,

as they descend tail first.

When they're wiggled their body length

well below the surface,

garden eels secrete a mucus

which acts as a cement

to harden the walls of the tube

they'll live in for the rest of their lives.

They'll even spawn within these burrows,

only extending on mass into the current

to feed on passing zooplankton.

Blue ribbon eels also rarely leave their holes

in their 20 year lifespan.

They don't congregate in large groups

but often pair up.

These ribbon eels have developed large flared nostrils

to act as nets to catch passing tidbits

and to detect any changes in current

that may forecast the approach of predators.

(dramatic instrumental music)

In this case, a notorious larger cousin.

The yellow-edged moray eel

can grow nearly two and a half meters in length.

It has a formidable set of teeth

to snatch crustaceans, fish, and other eels

in its nightly hunt.

Rather than burying itself in the floor,

it prefers a premade home a little higher up

in a coral bommie.

Bommies are columns of emerging reef.

Satellite suburbs away from the dense bustle

of the busy marine metropolis.

It's usually a small patch reef in a lagoon

growing towards sunlight in a column.

As the coral colonizes

and grows into a spire,

territorial animals like morays

will claim the home

and defend it from others of their own kind.

These patches also become

important geographical markers for ocean migrators

and pillars of industry

where marine business deals are exchanged.

The elongated body of the yellow-edged moray eel

is perfectly designed to wind its way

into protective nooks and crevices.

(dramatic instrumental music)

Here it sits with its body tucked inside

and the large toothed head poking out,

ready to strike at passing prey or interlopers.

This moray doesn't have the protection of scales.

Rather, it secretes a thick mucus coat through its skin.

To keep parasites at bay

and dead cells from building up,

it engages the services of a professional cleaner.

(playful instrumental music)

These coral bommies often double up

as a one stop marine cleaning station.

It's a competitive marketplace.

A number of species all vie for a customer's attention.

Several coral triangle shrimp species

are cleaners.

They rock and wave,

frantically advertising their availability.

Most cleaner shrimp

are thought to only see in gray scale.

Fish will stop and open their mouths

or fan their fins to indicate

they're ready to clean.

Some will even darken or lighten in color,

which the colorblind shrimp

can take as their cue to board.

With shellfish high on the menu for a moray,

this eel seems to have a feast at its doorstep.

But it recognizes the cleaners

and grants a Pacific cleaner shrimp

permission to board.

It's a delicate dance

to judge the right time for a deep clean.

The prized parasites live inside

of the moray eel's sizable mouth.

The benefit of a parasite clean out

far outweighs the nutritional profit of a single shrimp.

But a mistimed step

can irritate the moray.

It has an extra long holding tooth

on the roof of its mouth.

A sudden snap could be fatal.

Success.

The Pacific shrimp has got the job done.

Scavenger hinge-beaked shrimp

wait eagerly for scraps below.

Nearby, a bluestreak cleaner wrasse hovers.

It's also advertising its services.

The wrasse's ability to swim freely

allows it to tend to a wider range of clientele.

Cleaner station bommies

effectively act as a marine Switzerland.

A neutral ground where the usual

predator prey interactions are paused

and a ceasefire is declared

for the benefit of all.

(playful instrumental music)

A fish will signal readiness to be groomed

by slowing and moving into vertical position.

It then spreads its fins and gills.

The tiny wrasse works fast and efficiently.

They whip around the mouth

and even enter the gill openings

to devour thousands of parasites.

Their diligence is extraordinary,

completing up to 2,000 cleaning sessions daily.

Bluestreaks lump their fish clients into three categories.

Dangerous predators,

which, unsurprisingly, get top tier service.

They'll be tended to first.

Next are the floater fish.

These are astute clients

that roam from bommie to bommie

in search of the most efficient service.

In a competitive market,

wrasse will often squabble

over rights to a customer.

And finally, the coral bommie's residents.

These fish are often forced to wait their turn,

even if they arrive in line first.

The resident fish are often subjected

to a subpar service.

The bite and dash.

With skin and protective mucus,

offering a more nutritious meal

than ectoparasites alone,

a bluestreak has to make a tactical decision.

Will it nip off a little more than it should?

Bluestreak wrasse have very good memories.

They can keep track

of more than 100 individual clients

and can recall if their last interaction was positive.

If the cleaner is aware

it mistreated a valued customer last time,

it's more likely to follow up with a pleasant clean

and possibly even a fin massage.

(peaceful instrumental music)

The grand buffet of all clients

is one that travels far and wide

and has a large surface area

in need of constant grooming.

This bommie sits in a strong current of Milne Bay

in Papua New Guinea.

These underwater highways between bommies

are dense in plankton.

Easy pickings for filter feeding manta rays.

Where the plankton is heavily concentrated,

manta rays begin barrel rolling.

These tight loops keep them in the feeding zone,

working the water columns

while the nutrients are thick.

Some of these reef migrators

have traveled several hundred kilometers

in search of new nutrient rich currents.

They may stop over for a day

or stay in the area for months.

The manta train rolling into the station

is always cause for a flurry of excitement.

All cleaner species will compete

to tend to one of these oceanic giants.

In fact, some species

that aren't usually cleaners

will even temporarily take on the role

just for manta rays.

Small, vividly hued moon wrasse

are highly territorial,

harassing anything that ventures

into their home range.

Moon wrasse are not ordinarily cleaner fish.

However, their behavior changes

in the presence of a manta.

Seemingly smitten,

moon wrasse suddenly join the queue

of species vying for cleaning right.

They'll even follow the mantas

for long distances,

drawing them far from the home reaches

they fought so hard to protect.

Researchers are yet to identify

why manta rays have this hypnotic effect

on the moon wrasse.

When the mantas leave the bommie,

they'll venture far beyond

the protection of the reef

in search of new feeding grounds.

The outgoing passage

from the reef's safety to open ocean

crosses the outer reef drop off.

The drop off faces seaward

and slopes to the ocean floor.

Depending on the age and height of the reef,

the descent may be just a few meters

or a plunge down to 50.

This is where waves,

traveling hundreds of kilometers,

finally meet resistance.

It's a place for the hardiest of corals,

plates and brain corals.

Those strong enough to withstand

the constant buffeting.

The agitated surface water

stirs up algae and plankton,

sparking a web of feeding.

(dramatic instrumental music)

Fish schools of all size and shape

patrol the drop off

and the big predators know that.

Here the cues to mate, feed, and hide

all come from the tide and the skies above.

Anthias are the jewels of the reef edge.

(gentle instrumental music)

They're small, brightly colored,

and school in large numbers

for protection from seaward predators.

Anthias feed on the reef edges.

But on this particular dusk,

they have another agenda.

Within these super schools

are hundreds of harems,

a large male surrounded by several females.

The males are larger and brighter.

For several minutes around sunset

the amphias carefully time their rush into the water column

to release eggs and sperm.

Midnight snapper lurk meters below.

They patrol the seaward facing reef

for the tiny larval stages of animals

that make up drifting plankton.

For the amphias,

tonight's date has been chosen

to coincide with the conditions and currents

most likely to carry the genetic material

as far away in the open ocean as possible,

away from hungry mouths.

(gentle instrumental music)

How these fish all know

the precise time and place to meet

is undetermined.

They are here in the thousands.

Across the reef,

others begin their own courtship dance.

A porcupine puffer fish male

will spend days wooing a potential mate.

The courting window for mandarin fish

is within 20 minutes of sunset.

Males stake out a reef ledge

to transform into a stage

to put on a display of their vigor.

This female has come to watch the show.

Like a peacock on parade,

the mandarin male struts back and forth,

raising his dorsal fin

and flashing his colors.

The more dazzling he is,

the more likely she is to fall for his charms.

The female is impressed.

Together they align belly to belly

and rise about a meter above the reef.

They synchronize the release

of delicate spawn clouds

and, in an instant, the dance is over.

Inshore of the reef,

the day octopus ventures out

one last time before nightfall.

Notoriously solitary,

they barely even tolerate their own kind.

For this male,

an encounter with another male

leads to a quick arm wrestle

for the right of way.

When it does seek out company,

it's to mate.

The male stands tall

and raises 3D skin spikes, called papillae.

His approached display

catches the eye of a female

at the end of a day's hunt.

But the females are known to rebuff

unwelcome advances

and, on occasion,

eat their suitor.

A confident male will pounce and mount.

This octopus is cautious.

He employs a mating strategy

that keeps him at arm's length.

One of the male's tentacles

stores spermatophores,

small packets only centimeters long

that he must reach up and place

into the oviduct.

It sounds like a simple mission

but the female's oviduct

is within the same area

as her other vital organs.

The head.

With any luck,

she's had a successful day of hunting.

She accepts.

The more spermatophores he can place inside,

the likelier his lineage continues.

Flush with confidence,

the male attempts a second pairing at closer range.

(dramatic instrumental music)

This time he is less welcomed.

She attacks.

Her grasp loosens just enough

for the male to make his escape.

As the sun drops,

the reef's day residents

begin to take refuge.

(dramatic instrumental music)

Darkness will bring the night hunters.

Boxer crabs arm themselves.

No bigger than a bottle cap,

these crabs attach

stinging sea anemones

to their pinchers.

They wield the tiny stinging animals

like weapons,

waving off potential predators.

The anemone could deliver a nasty zap

for anything that ventures too close.

These boxer crabs

will even steal anemones from each other

during the night if they can.

Feather stars take flight.

These are 200 million year old animals

that look like plants.

Long ago, many species evolved

to swim or crawl to evade predators.

They anchor for the evening

in plankton rich currents.

Beyond the reef,

one of the greatest mass migrations

in the animal kingdom is taking place.

Billions of tiny marine creatures

begin a nightly ascent of several hundred meters

to feed on plankton closer to the surface.

Schools of large fish amass at the reef edge

looking for a final meal.

(dramatic instrumental music)

Others are looking for their first.

Whitetip sharks

are the reef's apex predator.

They are night hunters.

A smaller shark,

rarely more than a couple of meters long.

Reef sharks have learned to hunt in a pack.

The trevally's defense is also a number's game.

They confuse the sharks with large schools,

swimming together with others

of a similar size.

The whitetips are visual hunters.

The twisting and turning mass

makes it difficult to pinpoint

an individual target.

On the reef, standing out is like ringing a dinner bell.

Night hunts begin

right across all of the Pacific's reefs.

From the corners of The Coral Triangle,

to the west coast of the Americas,

an army of predators is on the march.

(dramatic instrumental music)

Even the tiniest of mouths are hungry.

A coral polyps animal nature awakens.

It catches and consumes a baby squid.

The sea is thick with larvae and plankton

and a feeding frenzy builds along the food chain.

A parrotfish spins a mucus cocoon

to ward off night crawling parasites.

But tonight, it's under attack

from something else.

Something much larger.

A reef shark pack is on the move.

They're armed with electro receptors

to detect the faintest electrical signal.

Even the elevated heartbeat of a fish in fear.

These whitetips detect the odor

of a distressed fish in the water.

Food is close

and the pack's feeding instincts

reach a frenzied pitch.

Incredibly, they still maintain

a form of pecking order amongst themselves.

Some pack members move to block off escape routes.

Their bodies are live enough

to squeeze into crevices.

Sometimes it's not quite enough

to stop the occasion misdirected bite.

Together, they work as a hungry hoard,

systematically flushing out hiding places.

It's a close escape for this fish

but the reef has many more in hiding

and this pack will hunt until dawn.

Across thousands of reefs,

decisions are being made in every second of darkness.

Fight or flee.

The wolfer life is played out nightly.

For every life sustained,

another is lost.

The digested carbon calcium fragments

of skeleton and shell

are the only remnants,

born again, somewhere as sand.

A minuscule contributor

to a new Pacific Ocean reef.

(inspiring instrumental music)