The Bahamas.
A beautiful island wonder in the wild-blue waters
of the Atlantic Ocean.
An underwater Eden for large and dangerous predators.
You can feel their power, their speed and their strength.
If you are a diver,
and if you have never seen a shark,
Bahamas guarantee you that.
Voracious, gentle giants...
Cunning and intelligent thinkers.
Sometimes you get a little nervous
because it's a smart animal,
you never know what it's gonna do.
Spectacular schools of fish,
giant underwater swarms
all caught in a daily battle for survival
and deep, mysterious underwater caves
that hold the key to the secrets of Earth's past
and future.
(♪♪♪)
The Bahamas.
A stunning nature-lover's paradise
spread over more than 100,000 square miles
of the Atlantic Ocean.
About 150 miles from Florida's south-eastern coast.
Its 3,000 islands, islets and cays
fringed by white, sandy beaches and calm, turquoise waters
were forged over millions of years.
The islands of the Bahamas rest on two massive banks
of limestone nearly two-and-a-half miles deep
and created by ancient marine sediments
such as sand and the skeletal remains
of coral reefs.
Just 30 of the Bahamas' 700 islands
are inhabited by humans.
27 National Parks spread throughout the archipelago
and provide protection for critical habitats
and endangered species such as the rock iguana.
(♪♪♪)
The Bahamas is roughly the same size as New York State
and is home to a dazzling array of diverse ecosystems...
Thick forests...
Twisty mangrove swamps...
And the deep and mysterious vertical submarine caves
known as Blue Holes.
But perhaps its most breathtaking ecosystems
lie under the clean blue water.
The world's third-largest barrier reef
measuring 190 miles long provides food and shelter
to more than 160 species of coral and fish.
(♪♪♪)
Shallow coastal waters nurture ancient creatures
perfectly adapted to life on the sandy bottom.
But the waters of the open ocean belong to sharks.
For a diver, the Bahamas will give you
for sure the guarantee
that you are gonna see some sharks.
So if you are a diver, if you have never seen a shark,
Bahamas guarantee you that.
Some 40 species of shark cruise these clear,
blue Bahamian waters.
These are nurse sharks...
Caribbean reef sharks...
And where the shallow turquoise waters
give way to the deep-blue,
one of the open ocean's great wanderers:
The Oceanic whitetip shark.
(♪♪♪)
Oceanic whitetips are stocky, heavy-set creatures
reaching weights of 370 pounds and lengths of up to 10-feet...
and are not to be confused with their smaller cousins:
Whitetip reef sharks.
Oceanic whitetips typically prowl the deep waters
far from shore.
This shark stays close to the upper layer of the ocean:
Its large, rounded dorsal fin breaking the surface.
Its dark, lifeless eye the size of a baseball.
The legendary oceanographer Jacques Cousteau
called these powerful, silent animals
"The most dangerous of all sharks."
It is a belief held by many
and stems from what has been called
"The worst shark attack in history."
In 1945, a United States naval ship
called the USS Indianapolis was sunk by a Japanese submarine
leaving about 900 men drifting in groups
in the waters off the Philippines.
Survivors of the torpedo attack recounted how sharks
believed to be oceanic whitetips
prayed for days on both the dead
and the living.
Oceanic whitetips are pelagic animals,
they inhabit those parts of the sea
that are neither close to the bottom
nor near the shore.
(♪♪♪)
The open ocean is like a desert
with little life and little food.
To survive out here
oceanic whitetips need to be bold,
opportunistic hunters urgently investigating
any possible source of food.
Some sharks will bump potential prey
before mounting an attack.
And there are stories of marauding oceanic whitetips
fearlessly circling and bumping uneasy divers.
(♪♪♪)
In the open ocean conserving precious energy is essential
for creatures on a boundless search for food.
Oceanic whitetips swim slowly though they are capable
of powerful bursts of speed
when in pursuit of fast-moving prey
such as tuna, barracuda and white marlin.
In this vast expanse of the open sea
there is nowhere to hide
and oceanic whitetips are equipped
with large triangular serrated teeth
used to clench and tear apart
their prey.
(♪♪♪)
Like all sharks the oceanic whitetip
has an acute sense of smell.
As it swims water passes into its nostrils
on the undersurface of its snout and across sensory cells
allowing the shark to locate prey by scent.
(♪♪♪)
Incredibly, each nostril can detect smells separately.
The shark is able to identify the direction of a scent
by which nostril detected the smell first.
(♪♪♪)
Oceanic whitetips swim with an entourage of pilot fish
so named because they were once believed
to lead, or pilot, larger fish to prey.
Pilot fish follow the sharks to feed on skin parasites
and left-over scraps of food.
They also conserve energy by hitching a ride
in the slipstream created by the larger fish.
(♪♪♪)
This shark has a tag attached to its dorsal fin
which allows a researcher to collect information
about its behavior.
(♪♪♪)
Because they live so far out in the open ocean
oceanic whitetips are among the least studied
of all marine creatures.
A large-scale tagging operation conducted by researchers
in the Bahamas made surprising findings:
Oceanic whitetips will roam as far as 1,200 miles
then return to their home base in the Bahamas
within a few months.
The first evidence of return-migration
in these sharks.
Commercial shark fishing is banned in the Bahamas.
But when sharks venture far from these islands
they enter dangerous waters.
Oceanic whitetips are often caught in long lines
set for other species.
The findings from this tagging operation
will be used in conservation strategies
to protect this species.
The oceanic whitetip was once one of the most abundant
apex predators on the planet.
But it is now considered critically endangered.
Overfishing has resulted in huge declines
in their population.
Oceanic whitetips are killed cruelly and illegally
for their fins.
The costly and destructive key ingredient
of shark-fin soup.
Each year, about 70 million sharks
are killed.
The Bahamas is one of the few places on Earth
where oceanic whitetips thrive in relatively large numbers
plying the open ocean consumed by the endless search
for food.
But oceanic whitetips aren't the only sharks
that flourish here.
The Caribbean reef shark is one of the largest predators
in the tropical coastal waters off the Bahamas
Reaching lengths of 10-feet and weights of up to 150 pounds.
Caribbean reef sharks are not dangerous to humans
unless provoked.
They are the main attraction of shark dives
in which bait is used to lure sharks
to within arm's length of divers.
It's not a dangerous animal.
Because of all this references to sharks,
people feel intimidated when they see a shark
or most likely they think that something is wrong
or something is gonna happen.
But I'd encourage anyone to feel safe
when they see a Caribbean reef shark
because they are scavengers, they have no interest in humans.
You never see a Caribbean reef shark
attacking a human.
If you're not a dead or sick fish,
you should have no worries about seeing
a Caribbean reef shark.
A shark is magic, it's majesty, it's elegant, it's excellent.
It's a warm fuzzy feeling that you get
because it's so beautiful,
they just glide through the water
and they have these little eyes, and they look at you
and they're not interested in you.
They're just living their life like a good neighbor.
So how do you feel?
You just feel freed.
The experience of coming eyeball-to-eyeball
with these majestic predators has proved popular
and shark-related tourism now brings an estimated
$40 million annually to the Bahamian economy.
And while humans may not be part of the food chain
of the Caribbean reef shark another species is not so lucky.
The southern stingray is a favorite food
of the sharks that prowl these waters.
They are the largest rays in this part of the Atlantic
reaching six feet in diameter.
Though they appear weightless floating over the sea grass
southern stingrays can tip the scales
at more than 200 pounds.
(♪♪♪)
Unlike most fish
the ray does not have an air bladder.
The internal organ that provides buoyancy
in the water.
If the ray stops swimming it will sink to the bottom.
But it is perfectly adapted to life
on the coastal sand flats of the Bahamas
feeding on molluscs and worms buried in the sand.
Electro-receptors on the underside of the ray
detect vibrations created by buried prey
which the ray uncovers by blowing water
through its mouth and gills
and flapping its large pectoral fins
to disturb the sand.
It is a feeding behavior known as "hydraulic mining."
The southern stingray is a peaceful fish
but if threatened, it will raise its long tail
like a scorpion to stab predators
with a venomous barb.
Divers and waders must exercise caution
to avoid an unwanted stingray encounter.
If you're shuffling your feet through the sand
and a stingray is aware that you're coming,
it will just swim away.
But if you were to suddenly step on one,
it would shoot that barb as a defense mechanism
to defend itself.
It's apparently a burning sensation,
a very painful sensation,
like a wasp sting, I say probably times a thousand.
Meanwhile, near the shoreline
is one of the most unique creatures in the Bahamas
the Cassiopea or upside-down jellyfish.
As the name suggests these jellies live upside down
on the sea bottom.
Their ancestors roamed the oceans
500 million years ago.
Upside-down jellyfish are farmers
offering algae a home among their tentacles.
Algae use photosynthesis to turn sunlight into energy
which is then absorbed by the jellyfish.
By floating upside down in the shallow water
the jellyfish provides ample sunlight to the algae
thereby getting itself a free meal.
One jellyfish alone is an extraordinary sight.
Millions of jellyfish altogether are spectacular.
A dense bloom of thimble jellyfish
shimmers in the twilight sea.
Thimbles are the most common jellies in the Bahamas.
They explode in swarms in the late spring
feeding on crustacean zooplankton and barnacle larvae
which they sting with venomous threads.
The uncoiling of these threads is one of nature's
most remarkable feats.
Each thread is armed with a venomous barb
that can fire faster than a bullet from a gun.
These vast swarms of jellyfish appear to be occurring
more often around the globe.
Either part of a natural cycle
or possibly the result of climate change.
As oceans warm jelly embryos develop more quickly
and jellyfish populations explode.
They may have no brains, no blood and no heart
but these thimble jellyfish can be a menace.
Swimmers can pass through a swarm
of invisible thimble jellyfish larvae
without even realizing it.
That is, until the appearance of a nasty, itchy rash
caused by the stings of young jellyfish
no larger than a speck of ground pepper.
As twilight turns to night,
an equally mesmerizing sight unfolds on the reef.
Tomtate, thousands of them.
It's something that makes you belong,
you are surrounded by life, life is all around you
and that's what you feel under the water.
With a big school of fish, if you move slowly and calm
they let you be in the middle and you feel surrounded by life,
very powerful life.
The sea never stops, never gets tired,
so it's a very special feeling.
Yes, very strong.
Each night, shortly after sunset
these tomtate migrate off the reef
to the sandy, sea grass beds
where they will prey on small, bottom-dwelling invertebrates
such as shrimp, crabs and molluscs.
Just before sunrise they will return, en masse,
to the safety of the reef.
Tomtate are just one of about 150 species of marine fish
known as grunts.
As their name suggests these fish make a grunting sound
that is caused by the grinding of their teeth.
The peculiar noise made by a grunt
is not unlike that of a pig.
The creatures of the ocean are locked in a daily battle
for survival and like many fish
tomtate swim in schools to protect themselves
from predators.
Targeting individual prey from a tightly packed school
is no easy task for a visually oriented hunter.
For the tomtate, there is safety in numbers.
Swimming in unison the fish may appear
as a single large creature to would-be predators
such as groupers and sharks.
Schooling also helps the tomtate forage for food
on the sandy sea bottom.
Thousands of eyes are better than two
and can mean the difference between finding prey
or going hungry.
There is another reason why fish swim in schools:
To conserve energy.
Those at the back of the school are pulled along
by the slipstream created by their neighbors
conserving precious energy needed for this nightly forage.
Schooling fish maintain
these stunning synchronized formations
by using what's called a lateral line:
Cells along the head and body
that are sensitive to gentle currents
and vibrations.
As a fish swims, it displaces water
which creates ripples.
When those ripples hit the lateral line
of another fish
it is able to detect both the direction
and the speed of its neighbor.
This allows the school to turn with astonishing precision
and to close ranks tightly in the presence of a predator.
(♪♪♪)
A cloud of sand is stirred up by one of the largest predators
in these waters:
The nurse shark.
These bottom-dwelling hunters can reach lengths
of up to 14-feet.
For divers getting close to even a smaller nurse shark
can be exhilarating.
Of course, you can feel their power, their speed
and their strength.
They may be five feet
but these guys can swim very fast
in a very explosive wave,
something that for a diver is completely impossible.
They are very peaceful,
and one of the beautiful creatures of the underwater.
(♪♪♪)
The nurse shark is an apex predator
in the Bahamas.
Only larger sharks feed on these strong hunters.
At night, it prowls the sandy bottom.
Using a whisker-shaped organ near its mouth
called a "barbell" to detect shrimp, squid
and lobsters.
It sucks them into its mouth with tremendous force
and swallows them whole.
Then expels inhaled sand through its gills.
As the night begins its retreat
the nurse shark will return to the submerged ledges
on the reef to rest up for the next night-time hunt.
Another day breaks in the Bahamas.
These islands sit atop a thick bed of limestone
comprised of sand and the broken skeletal remains
of marine organisms.
Limestone is porous
and saltwater from the surrounding seas
penetrates the rock beneath the island surface.
During past ice ages fresh rainwater
made acidic by carbon dioxide in the air and soil
percolated down into the earth.
It mixed with the saltwater eating away at the limestone
to form sink holes, hundreds of feet deep.
As the Earth warmed and oceans rose
sink holes filled with saltwater
creating dark and mysterious underwater caves
that may now unlock the secrets to the Earth's past
and its future:
Blue Holes.
The Bahamas contain the highest concentration
of blue holes on the planet.
In the dark waters deep below the surface
is an ecosystem unlike any other on Earth.
A thin layer of fresh rainwater sits atop a denser layer
of salty marine water.
The freshwater lens prevents oxygen in the air
from reaching the salt water.
Yet somehow, extreme life forms manage to thrive
in these deep, oxygen-deprived waters.
Cave-diving scientists have discovered
colonies of microbes
that are toxic to most other organisms.
By studying these hardy bacteria
that are able to survive in the anoxic waters
of blue holes,
researchers can deepen their understanding
of what life was like on the planet
more than three billion years ago
when earth was an oxygen-free environment
and bacteria the primary life form.
Similar inhospitable conditions
exist on distant planets and moons.
The mysterious blue holes of the Bahamas
may hold the key to how life is able to survive
in oxygen-free environments on Earth and beyond.
These blue holes also act as a time capsule.
Deep sheltered waters that are low in oxygen
are ideal for protecting fossils.
The skeletons of ancient crocodiles,
tortoises and bats have all been found here
remarkably preserved.
Without blue holes much of the fossil record
of the Bahamas would be gone destroyed by hurricanes
and exposure to the elements.
For divers, each descent into a blue hole
is an opportunity to visit a strange and distant past.
It feels like you are diving through the arteries
of Mother Earth.
You are going through the history of geology
of our planet.
It's like flying and getting into another time.
You stop thinking about anything else.
These vast underwater chambers house monumental formations
that hang like glowing icicles.
These are stalactites.
They are formed when dissolved limestone
in the water escapes into the air
and hardens as calcite.
Over time, miniscule amounts of calcite
build up and drip from the cave ceiling.
(♪♪♪)
Mineral-rich water that seeps through the cave ceiling
or drips off the end of stalactites
creates stalagmites
which rise from the cave floor.
Each of these remarkable sculptures begins
with a single drip.
You feel in another world.
You are no longer in the normal living realm of your days.
You are under the water in a cave
sometimes 600-feet in into a cave
and you are just enjoying but also are very focused
in what you are doing exploring a new territory.
Few have explored the farthest reaches
of these vast and twisting underground waterways.
Cave diving is extremely dangerous.
In the darkened depths
it is easy to become disoriented.
A single wrong turn or equipment failure
and you're doomed.
Hundreds of divers have perished in caves like these.
It's believed that less than 20%
of the 1,000 blue holes in the Bahamas
have been explored.
These dark underwater passageways
remain one of Earth's final frontiers.
On the island of Eleuthera
another unusual underwater environment
continues to fascinate scientists.
An inland saltwater lake, separate from the ocean
is home to an extraordinary and intelligent creature.
This is the Caribbean reef octopus.
The octopus are believed to be the smartest
of all invertebrates on the planet.
Experts believe they have the intelligence,
memory capacity and skills development
of a three-year-old child.
In captivity, they have managed
to unscrew a bottle cap to remove a crab inside.
In the wild, an octopus can remember
the location of a predator and stay clear.
When faced with a predator the octopus is armed
with multiple defense strategies.
It is one of the few creatures on Earth
able to completely alter its appearance in a flash.
Thousands of color-changing cells
just below the surface of the skin
allow it to blend in with its surroundings.
A complex network of muscles and nerves
controls projections on the skin
creating bumps and spikes
that match the texture of plants or rocks.
Predators such as sharks and dolphins
may swim over the octopus without even noticing it.
If discovered, an octopus can make a fast getaway
by sucking water into its mantle
and expelling it through a siphon tube
to jet through the water.
When cornered, an octopus will release
a cloud of black, foul-tasting ink
to blind and disorient an attacker.
And even dull it sense of smell
while the octopus makes its escape.
And if caught by a predator
the octopus has a remarkable last line of defense.
It is able to lose an arm
then miraculously regrow it later
without lasting damage.
In this saltwater lake there are few predators
and the octopus swims freely on the lookout
for crabs and molluscs.
It grips prey with powerful arms
as long as eight feet then paralyzes it
with nerve poison secreted in its saliva.
The oldest known octopus fossils date back
almost 300 million years.
Well before the age of the dinosaur
creatures like these have roamed the oceans
adapting perfectly to their surroundings.
The octopus has three hearts:
Two pump blood to the gills
the third keeps circulation flowing for the organs.
When the octopus swims the third heart stops beating.
It crawls along the sea bed to conserve precious energy.
In the shallow seas that flank the islands of the Bahamas
sunlight penetrates the surface nourishing the sea grass
which in turn nourishes
one of the ocean's gentle giants:
The manatee.
These peaceful, slow-moving creatures
are sometimes called "sea cows"
though they actually evolved from the same land animal
as the elephant more than 50 million years ago.
At 10-feet long
and reaching weights of up to 1,200 pounds,
the average adult manatee is similar in size
to a large polar bear.
A powerful tail pushes the manatee
along the sea meadow.
It will cover three to five miles in an hour.
Manatees are voracious herbivores
and will spend up to 12 hours a day
feeding on sea grass, weeds and algae.
A manatee can consume 10% of its body weight
in plants every day.
Coarse hairs around its lips
enable it to detect and grasp plants
especially helpful when the manatee
is feeding in murky water.
Scientists believe the bristles are as sensitive
as a human fingertip.
Like all marine mammals manatees must surface
to breathe air.
A resting manatee can stay submerged
for as long as 20 minutes by slowing its heart-rate
by 80% to conserve oxygen.
When the manatee does take a breath
it replaces 90% of the air in its lungs.
In comparison, humans replace just 10%.
Manatees are sluggish and docile.
They have no defense mechanisms
because they have no natural predators.
And yet these placid creatures are at risk of extinction.
They are illegally slaughtered by hunters
seeking their hides,
carelessly entangled in fishing nets
and accidentally killed by motorboats
in the shallow coastal waters favored by these gentle beasts.
(♪♪♪)
At the surface
another air-breathing marine creature
catches a breath.
The loggerhead turtle is the largest
of all hard-shelled turtles in the sea
and is named for its sizable log-shaped head.
This female is about five-feet long,
her shell is as broad as a table for four.
Loggerheads swim slowly
but are capable of bursts up to 20 miles an hour
when fleeing predators such as sharks.
You feel small compared to them
and they're so fast, they are so agile
under the water.
We as divers, even with the best buoyancy
that we can achieve,
we are not so good swimmers as them.
This loggerhead turtle has company:
The remora, or suckerfish,
are highly specialized creatures.
A modified dorsal fin on the top of its head
acts as a suction cup and allows it to cling
on the turtle for a free ride.
Remoras will feed on parasites and bacteria
on the turtle's shell as well as left-over scraps.
(♪♪♪)
The loggerhead's days are spent soaring to the surface for air
then down to the bottom to search for prey.
Powerful jaws crush jellyfish, conch and crabs.
Older loggerheads such as this female
show no fear of divers.
Loggerhead turtles have an enormous range.
An adult female will migrate thousands of miles
from its feeding ground to lay its eggs
on the same beach where it hatched, years before.
These warm and shallow waters are home
to another long-distance traveler:
The green sea turtle.
Like its cousin, the loggerhead,
its homing behavior is remarkable.
Tiny magnetic particles in the brain
allow it to use the Earth's magnetic field
to navigate the open ocean
to locate the exact stretch of coastline
where its life began.
Hatchlings have been observed tasting the sand
as they scurry down the beach to the surf.
It's believed this is to create a chemical memory
of their birth place
so they may return to the same spot
in 12 to 15 years to continue this cycle of life.
(♪♪♪)
Life in the open water of the Bahamas is a struggle.
By returning to a successful nesting site
to lay its own eggs,
the sea turtle increases the odds of survival
for the next generation.
Unlike most sea turtles,
the adult green sea turtle is a true herbivore.
It feeds entirely on algae and sea grass
which colors its fat green
and gives the green sea turtle its name.
They eat as much as five pounds of sea grass a day
and control the growth of these flowering plants.
They are the "cattle of the sea."
Without the green sea turtle
this sandy sea floor would be invisible.
(♪♪♪)
Beautiful white-sand beaches
fringe the islands of the Bahamas.
Comprised mainly of the shells and skeletons
of marine organisms.
The fine sandy bottom extends for miles into the sea
and underpins the oceanic food chain.
Plants that grow in the sand
provide food and protection for fish
which attract one of the ocean's most playful
and intelligent creatures:
The Atlantic spotted dolphin.
It's not that easy to get close to the dolphins
unless they want it.
Of course, they feel like they don't know you,
they don't know if you're a threat.
But when they feel curious and they feel safe,
they can swim around you very fast very agile.
They are like surfers under the water.
I wouldn't say spiritual, but it's a loving feeling inside
when you embrace something like that.
That has such intelligence such power and speed.
It's a good feeling,
sometimes you get a little nervous
because it's a smart animal,
and you never know what it's gonna do.
Atlantic spotted dolphins are social animals
traveling through these shallow coastal waters
in pods of 10 to 100.
Groups can include males and females,
adults and young dolphins that are yet to develop
their trademark spots.
Like whales dolphins breathe air
taking in oxygen at the ocean surface
through a blowhole on top of the head.
And just like whales
dolphins are "conscious breathers."
They never fall completely asleep.
One hemisphere of the brain always remains awake.
So, even while sleeping
the dolphin is able to surface for air
and remain alert to predators.
Their brain-to-body ratio
which is believed to be a measure of intellect
is second only to humans.
Dolphins use touch and posture to communicate.
These three touch fins to stay in contact
as they accelerate through the water.
Swimming belly up can signal a male's interest in mating.
In a large social group
efficient communication is essential.
Dolphins use clicks and whistles to keep in touch.
Each member of the pod uses a signature whistle
to identify itself:
A useful tool for a mother keeping track
of a young calf.
Adults emit loud pulses of sound...
(Dolphin pulsing)
...to discipline young dolphins or even scare off sharks.
Even more impressive is the way these dolphins see with sonar.
They are expert at echo-location
making clicking sounds as many as 500 per second
that travel through the open ocean
bouncing off of potential prey and echoing back to the dolphin
to reveal the size, shape and location
of a potential meal.
This sensory system is so precise
that dolphins have been employed by the US Navy
to locate underwater explosives.
The complex social network of dolphins
is designed for one purpose:
Survival.
Dolphins will coordinate hunts, herding,
and then harvesting schools of fish.
A whistle then signals the catch
to other dolphins in the group.
Spotted Atlantic dolphins have also been seen
taking part in post-mortem rituals
that researchers believe are consistent with grieving.
Adult dolphins will use their backs and heads
to buoy up recently deceased calves
at the surface as if unwilling
to part with the dead.
Adult dolphins will hold on to their dead young
for as long as 30 minutes
before surrendering them to the sea
where they will nourish other creatures,
energizing the food chain
and ensuring new generations will thrive
in this beautiful and complex underwater world.
From rich coral reefs and deadly underwater caves
to apex predators of the open ocean
and majestic creatures linked to a prehistoric past,
the Bahamas is a treasure trove for explorers
and one of the many wonders of the Great Blue Wild.
In the Bahamas we have great visibility,
end of story.
I think what is special about it is
is the geological landscape and the fact that
it's unspoiled and it's really unspoiled.
It's a magical place, very still.
You feel like a good strong contact
and in balance.
With 70% of the planet is water,
so diving puts you really close
to what it's like to feeling and living on this planet.
(♪♪♪)