Around a tiny
chain of islands
off the coast of Oman,
the stage is set for one of
nature's greatest spectacles.
Summer weather drives
nutrients in
from the oceans depths,
where they meet
the Arabian sun,
causing an explosion
of life.
For four months,
there's a feeding
opportunity like no other.
Creatures journey from far
and wide to join the feast.
Ocean travelers like
hawksbill turtles
and seabirds.
But no visitor
is more dramatic...
than the largest fish
on earth:
the whale shark.
This whale shark
is a tiny giant.
Nine feet long, just a third
of his full potential.
Based on his small size,
he's probably just entering
his teenage years.
The little giant's
on the move.
But he's not alone.
A larger male...
and a huge female
are traveling nearby.
Whale sharks are mysterious.
Despite being the biggest
fish on the planet,
they're poorly known
and endangered.
These three are part
of a population
of 500 whale sharks
that live most of the year
in the Arabian Gulf.
The gulf stretches between
Iran and Saudi Arabia
for more than 600 miles...
providing nearly 100,000
square miles of inland sea.
Setting out
on an epic journey,
the sharks are leaving
waters north of Qatar,
passing the coast of
the United Arab Emirates
on the Arabian Peninsula.
They avoid the shallows,
as they pass the coast
off Abu Dhabi.
The shallow seas
of the Arabian Gulf
can reach over 95 degrees.
The waters here are
sweltering and very salty.
They create the perfect
conditions for mangroves
and a number
of bird species.
(Squawking)
Below the waves,
seagrass meadows waft
like open prairies.
Rich in fish, the meadows are
a favorite hunting ground
for humpback dolphins...
..and fish-loving osprey.
Despite the abundance,
for the whale sharks it
might as well be a desert.
They typically avoid
the shallows
because there's little here
that they can eat.
Instinct drives them
forwards.
They know there are feeding
opportunities ahead.
Beyond the Arabian Gulf
lies the Gulf Of Oman:
cooler, deeper water
where life abounds.
Within this safe haven,
tucked nine miles
off the coast of Oman,
is a chain of rocky islands
known as
the Damaniyat Islands.
At first glance, the
dramatic rocks appear barren
and uninviting.
But the real riches
lie beneath.
Here, the slightly
cooler waters
create
the perfect conditions
for corals to grow.
Like an oasis in the desert,
the coral reefs are magnets
to marine life...
..offering food and shelter
to a colorful community
of residents.
The reefs support
over 100 species of coral
and nearly 600 species
of fish.
It's June.
Along the southern shores
of the Arabian Peninsula,
the waves are churning.
This brooding sea marks
the start of the monsoon.
(Thunder rumbles)
Driving weather fronts,
winds and currents
race north across
the Arabian Sea...
..stirring up cold water
from the ocean depths...
..and battering
the Arabian Peninsula.
But tucked inside
the Gulf Of Oman,
the Damaniyats are protected.
Ideally located,
the islands are sheltered
from the ocean storms,
but do receive swirling
eddies of cold water...
..that bring with them
nutrients from the abyss.
The Damaniyat Islands
are in a prime position
to host a dramatic
explosion of life.
Seabirds spend most
of their lives offshore
but, sensing a change
in the seasons,
they start homing in
on the islands.
They need to return
to their breeding sites
and find their mates.
A critically endangered
female hawksbill turtle
joins the journey.
She was born on the islands
and it's also time for her
to return to breed.
She travels 600 miles
between her feeding
and breeding grounds
and can set a good pace...
..covering 12 miles a day.
She's been swimming
continuously for weeks.
But her effort
is about to pay off.
Any day now...
she'll reach the islands.
When nutrients from the
ocean meet Arabian sunlight,
it creates the perfect
conditions for growth.
Thanks to this seasonal
fertilizer,
productivity of marine life
can increase tenfold.
Tiny plant-like algae bloom,
the basis of the ocean's
food chain.
The dominant species
covering the reef is coral.
These tiny animals
form huge colonies,
laying down
protective shells
that become the foundation
of the reef.
Corals are prolific,
but they grow slowly
and only when it's warm.
The cooler monsoon
conditions tip the balance
in favor of microscopic
plant-like algae
that thrive
in the frigid currents.
They grow faster
than the corals,
cloaking the reef
in thin green filaments.
It's a welcome feast for
some of the smaller locals.
So-called dancing shrimps
use their tiny pincers
to pick the algae
from the coral fronds.
These seasonal greens
break up their typically
carnivorous diet.
Their foraging
will help ensure
the algae doesn't drown out
the coral.
Wrasse, in turn,
enjoy feasting
on the small creatures
of the reef.
Wrasse are key players
in the reef ecosystem.
They comprise the second
largest family of marine fish
and are abundant on reefs
all over the world.
The most common around
the Damaniyat Islands
are these big shoals
of crescent wrasse.
They're also known
as moon wrasse
in both cases because
of the yellow,
crescent-shaped portion
of their tails.
This gang has a complex
social structure.
A larger and more colorful
dominant alpha male
maintains a harem of lesser
males and females.
They're a rowdy bunch,
constantly squabbling,
nipping at their
shoal mates...
..or any other fish
that get in their way.
The big dark-blue male
is about 18 inches long.
His minions are smaller
and greener in color.
They may be small, but they
have fiery tempers
and can hold their own
on the reef.
As the monsoon conditions
heighten,
productivity increases,
filtering through every
level of the food chain.
The churning waters
become cloudy
with dense wafting blooms
of tiny algae
called phytoplankton.
These, in turn,
feed zooplankton,
the minute larval forms
of shrimps and crabs
that drift in the ocean.
Carried by currents
through the open water,
the bloom of plankton
acts as a dinner gong
to the creatures
of the reef.
Many small species
of fish dart away
from their safe crevices
in the coral
to snack on this
profusion of plankton.
The larger crescent wrasse
join the feast.
Everyone wants to eat
as much as they can
as quickly as they can.
The monsoon will
only produce these riches
for a few months.
But this abundance of food
is a mixed blessing
for the fish.
(Squawking)
Birds flock over the waves.
They've travelled vast
distances to take advantage
of the densely-packed
pickings.
White-cheeked terns pluck
small prey from the surface.
(Chattering of terns)
Bridled terns have also
made the journey,
but not solely to feast.
They've timed
their breeding season
to coincide with
this abundance of fish.
But first they must find
their mates.
About a third of bridled
terns are monogamous
and will reconnect
with the same partner
for several years.
Not all couples
will be reunited.
The sea's a dangerous place.
Storms and predators
can take their toll,
and some travelers
don't make it back
to the sanctuary
of the islands.
This male bridled tern
scans the horizon.
The faithful featherweight
ignores the singletons.
He hasn't seen his mate
for nine months
while he's been out at sea.
He waits to see if she can
find her way back to him.
The tern colony
is very strategic
in where it makes landfall.
Away from the mainland,
the islands are free
of mammalian predators
like rats
that would eat their eggs.
The Damaniyat Islands
also provide easy access
to the food-rich reefs.
Below the waves,
the feasting continues.
Thousands of deadly
ocean wanderers
emerge from the blue,
lured to the islands
by the smaller fish
feasting
on the plankton bloom.
These are striped,
or Indian, mackerel,
each a foot of muscle
built for high-speed pursuit.
Larger still, the three-foot
Talang queenfish,
a powerful solitary hunter.
Joining them, six-foot
stripy brown cobias.
All of these predators
usually trawl the open sea
looking for prey.
But they have easy
pickings here.
Their targets
are smaller fish
that risk leaving
the safety of the reef
to enjoy the plankton soup.
The appearance of these
deadly shoals is a prelude,
a sign that summer
is well underway,
and conditions are just right
to lure in the ocean giants.
The unmistakable form
of a shark
dwarfs the huge cobia.
The first of the travelers
arrives from
the Arabian Gulf.
The largest whale shark ever
recorded was 65 feet long,
and tipped the scales
at 37 tons.
Whale sharks are the biggest
fish on earth.
But, mysteriously,
all of these newcomers
are juveniles,
only a fraction
of that size.
Whale sharks can live
for a century,
but, based on their size,
these are probably
twenty-somethings.
Despite their relatively
young age,
they've made
this journey before.
Whale sharks
are highly migratory,
ranging over vast distances
around the warm oceans
of the world.
Between June and October,
the juvenile giants
grace the reefs of Oman
with their presence.
They bring with them numerous
other ocean travelers.
These three-foot-long
remoras are hitch-hikers.
Their dorsal fins
are highly modified,
with a sucker on the top
of their heads.
They swim up
to larger animals
and clamp onto the host's
skin with the suction cup.
When space is running out
below,
they cling
to the top of the fin,
which means turning
upside-down.
Though with
their streamlined shape,
it's hard to tell
which way is up.
When a remora wants off,
it simply swims forwards,
releasing the vacuum.
By riding bigger animals,
the remoras travel
over large distances,
but hardly
expend any energy.
They steal crumbs
from whatever their host is
eating and consume its waste.
To pay their way,
they remove parasites
from the whale shark's skin.
It seems the whale shark
is fed up
of quite so many
uninvited guests.
The remoras won't be easy
to shake off.
They know their ride
is taking them
to good feeding grounds.
Unlike many sharks,
the whale shark is not armed
with ferocious teeth.
He's a filter feeder,
carefully sieving plankton
from the sea.
Like all sharks,
whale sharks can detect the
faint electrical pulses
of other animals
in the water,
so that they can sniff out
the tiniest traces of food.
An ever-growing entourage
of cling-ons gathers
to take advantage
of the young behemoth.
These golden trevally
edge towards the giant,
looking to shelter
against his bulk.
The juvenile trevallies
will become
fearsome hunters
in adulthood,
reaching nearly four feet
in length.
But these infants are still
small enough
to be food for fish
like the large cobia.
Riding the pressure wave
ahead of the huge shark,
they can also save energy
and pick off plankton
before it disappears
down the shark's gullet.
As June progresses, more and
more whale sharks arrive.
There are other species too.
The female hawksbill finally
makes it to the Damaniyats.
At three feet long,
and weighing in at 170 lbs,
she's no small fry.
Though she will
occasionally eat fish,
the profusion of prey
doesn't interest her.
She's quickly greeted
by another hawksbill,
a curious younger female.
But the older turtle
isn't here to socialize.
She's on a mission.
She's come here to mate
and lay eggs.
Mature males, distinguished
by their long thick tails,
are already making themselves
at home on the reef.
An old salty seadog...
..this male has spent
decades at sea.
Like the whale sharks,
he's picked up hitch-hikers.
Not just barnacles,
but also a huge conch.
The conch is a sea snail
and uses a rasp-like tongue
to scrape algae
off the turtle's shell.
The first month
of monsoon conditions
brings in many new visitors.
And now,
as June moves into July...
..the next phase of life gets
underway in the Damaniyats.
The male bridled tern is
still waiting for his mate.
But around him
the colony grows.
Like the turtles,
the seabirds time their
arrival on the reef to breed,
knowing that
the seasonal abundance
will provide well
for their chicks.
The island's low vegetation
gives the male a vantage
point to scan for his mate.
This tern's lost a leg
on its journey
perhaps to a large ocean
predator like a shark.
He's one of the lucky few
that survive such trauma.
The injury doesn't seem
to have affected his health
and won't impact
his fishing skills.
But he's a reminder of the
hardships of life at sea.
Bridled turns
are characterized
by their striking
black and white faces.
Each of the birds has
distinctive markings
to help them recognize
each other in a crowd.
Most settle on the ground...
..near other birds
like sooty gulls...
(Shrieking)
..and these swift terns
with their large
yellow beaks.
Close cousins
to the bridled terns,
the swift terns are pale
with black caps.
They bundle together
in tightly packed colonies.
(Squawking)
There are about 4,000
breeding pairs
around the coast
and islands of Oman.
(Squawking and cackling)
They space themselves out at
neck length from each other.
The occasional peck
reminds neighbors
of the boundary lines.
Nesting so close together
provides safety
from predators.
There are more pairs of eyes
to look out for danger,
and more birds
to work together
to drive away any threats.
The bridled terns, however,
prefer a bit more space.
The love-struck male's mate
has finally made it back
from her winter at sea.
The couple reaffirm
their bond
through a courtship dance.
They need to maintain
their close bond
to present a united front
against other pairs
that would like to muscle in
on their relationship,
or their newly chosen
nest site.
They're going to have
to work closely together
if they're to successfully
raise a chick.
Usually ground nesters,
the bridled terns
will use the barest scrapes
in the rocks
in which
to lay their eggs.
Some seek
a springier mattress.
The low-lying vegetation
provides a little more cover
for the nest
to keep out the neighbors.
Sooty gulls
can be egg thieves.
(Thunder rumbles)
By the end of July, the
monsoon reaches its peak,
stirring things up for
the Damaniyat islands.
Both residents and visitors
make the most
of its seasonal riches.
The young whale shark,
still looking
like a floating commune,
plows on in his mission
to feed.
The great arching slits
along the side of his head
are modified gills.
Water goes in through
the mouth
and out through
these openings.
They house gill rakers,
hair-like structures that
catch particles in the water,
trapping even
microscopic plankton
as the water passes through.
The retained food can
be wafted to the throat
and swallowed.
A medium-sized whale shark
like this one
filters more than
160,000 gallons,
collecting 6 lbs. of food
per hour.
Recent studies suggest
a shark like this male
will consume around 46 lbs.
of food a day.
That's the equivalent
of 184 typical hamburgers.
In addition
to filtering food,
the gills are also
responsible for breathing.
The whale shark must
always keep swimming
to pass oxygenated water
through its gills.
Like other open-water sharks,
if he stops swimming,
he'll die.
(Squawking)
By mid August,
thousands of birds
are nesting on the islands.
The reunited bridled terns
have a nest site
and are ready
to lay their eggs.
The swift terns
have already laid theirs.
It's hot weather
for brooding.
They all face
into the breeze and pant,
trying to keep cool.
Some stand over their eggs,
shading them and allowing
the breeze to circulate.
The eggs are mottled
for camouflage.
For many species of birds,
the unique markings
also allow the parents
to distinguish their eggs
from those
of their neighbors.
It's been shown
that swift terns
don't have these skills.
Even after they hatch,
it takes a few days
before these birds are able
to recognize their own young.
Occasionally, an egg
is damaged or infertile,
or one of the parents
is lost at sea
and the nest is abandoned.
Without an adult shading it
from the sun,
the egg will boil
in the heat.
Nearby, the sooty gulls
have laid two.
The female takes over
nest-shading duties
while the male patrols
the tern colony.
This abandoned
hard-boiled egg
would make a good meal.
But the terns stand
shoulder to shoulder,
so that there is
no way through
the densely-packed flock.
It's not just the birds
laying eggs.
With so much food available,
the Damaniyats' marine life
is also ready to breed.
All crescent wrasse
are born female,
but as they mature, some
of them will become male,
a process that takes
just ten days.
Now that the breeding season
is getting underway,
that transformation
is taking place for some.
With new males around,
the big blue dominant male
will have to work harder
if he wants to be the one
to breed with the females.
Parrotfish are
also breeding.
Like the wrasse,
their shoals are a mixture
of drab youngsters,
mature females,
and a big, colorful,
dominant male.
As the excitement grows,
the males follow the females.
They all dash out
and release sperm and eggs
by the millions.
It's a scattergun approach.
The idea is that
if enough are pumped out,
at least a few of
the eggs and sperm
will fertilize each other
and manage to escape
the other fish
that gather to feed on them.
Some of the crescent wrasse
risk venturing
far above the safety
of the reef
to launch their eggs
directly into the current,
so that they'll be carried
away from the hungry mouths.
The fish orgy creates a soup
of caviar.
Mass spawning events
are common.
It makes sense
for many animals
to release their eggs
at the same time
to limit the chances
of them all being picked off
by predators.
Despite the abundance
of eggs,
perhaps only one in a million
will survive to adulthood.
The hungry wrasse gang,
and a vast array of
other opportunists,
hang around below,
waiting for any eggs
that sink to the sea floor,
even if it means
cannibalizing their own.
This is a fish-eat-fish
world.
Only a lucky few will
survive the onslaught.
This breeding bonanza is what
has prompted the whale sharks
to swim hundreds of miles
to join the feast.
Individual sharks sometimes
hover over particular reefs
for as long as 14 hours,
waiting for the spawning
to take place.
The male uses
a gulping technique
to vacuum up thousands
of eggs.
Despite their fame as
the world's biggest fish,
whale sharks
are still an enigma.
The species itself has only
been known to science
for 200 years.
Many aspects of their
biology remain poorly known.
Both accidental
and deliberate fishing
for meat and fins
are driving down
whale shark numbers.
As their populations
diminish,
greater efforts are being
made to understand them.
It's believed that around
three-quarters
of the world's whale sharks
live in the Indo-Pacific.
But even these populations
have declined by around 63%
in just 75 years.
Protected reserves, such
as the Damaniyat Islands,
are a vital sanctuary.
Hawksbill turtles, too,
are in trouble.
They're
critically endangered
due to hunting,
entrapment in fishing gear,
harvesting of their eggs
and the destruction
of their nesting beaches.
But they, too,
find protection
in the Damaniyat Islands.
This female hawksbill
was likely born here.
After hatching, she will have
gone out to sea for 20 years
until she reached maturity.
Now she returns
to the same beach
every two or three years
to lay her eggs.
Since arriving on the reef,
she's mated and now carries
over a hundred fertilized
eggs inside her.
Hawksbills feed mostly
on sponges and soft coral,
which they demolish
with the tough beaks
that give them their name.
But the female's not eating
as much sponge as usual.
Instead she's devouring
harder pieces of the reef
for calcium carbonate
that will help with
the formation of eggshell.
As the turtle feeds, she's
breaking off bits of coral,
flushing out
the small creatures
that were hiding there.
For that reason,
she has a posse in tow.
The crescent wrasse
and other reef opportunists
are hot on her heels,
picking off any scraps
in her wake.
She will wait until
the cover of darkness
before she drags
herself ashore,
digs a nest
and lays her eggs.
The island has
so much to offer
that both the turtles
and the whale sharks
make their vast journeys
to get here.
Both cover similar distances,
roughly 500 miles.
The turtles move up
from southern Arabia...
..whereas the whale sharks
travel down the Arabian Gulf
from the north.
Unlike the breeding turtles,
only juvenile whale sharks
migrate to the Gulf of Oman
for the plankton feast.
It's possible the reef's
like a summer camp,
a seasonal, teenage hangout,
where the sharks can bulk up
and ready themselves
for adulthood.
This male is the smallest
whale shark
ever recorded in the region
at just nine feet long.
Scientists can distinguish
individuals
by the patterns
on their skin.
Each is as unique
as a fingerprint.
So far,
500 have been identified
in the Arabian Gulf.
By September,
the whale shark numbers
are reaching their peak.
This larger individual,
a huge female
about 26 feet long,
is a rare sight in
the Damaniyat Islands.
Only 30% of the sharks
that come here are female.
Just why isn't clear.
The season's
passing quickly.
Fish have spawned,
the bird colony's well fed,
and the sharks continue
their gorging.
But the favorable conditions
that follow the monsoon
only last for four months.
By October,
things are changing.
The nutrient-rich
upwellings decrease,
and higher temperatures
return to the reef,
as warm surface waters
once again
push in towards Oman
from the Indian Ocean.
(Squawking)
Exhausted from raising
their families,
the last small flocks
of terns bathe,
cleaning their feathers,
readying themselves
for the next eight months
feeding out at sea.
These will be the last days
together
for the young couple
this season.
Soon, they'll head off
to drift around
the Indian Ocean.
But, hopefully, they'll pair
up again next summer.
As the birds leave, the stage
is set for new arrivals.
60 days after their eggs
were laid,
tiny turtles emerge
from the sand.
The sheltered bays of the
Damaniyats offer sanctuary
to green
and hawksbill turtles,
both of which
are critically endangered.
Most turtles hatch
during the night,
but it's not uncommon
to see some emerge
during daylight hours.
With soft shells
an inch and a half long,
they're extremely vulnerable
to predators.
Somehow, imprinted
in their tiny brains,
is the knowledge to migrate.
Instinctively,
they head for the water.
Where these little ones
will grow up is unknown.
They'll drift
with the ocean currents,
feeding far out at sea.
Only a fraction
will survive.
But those that do might not
visit the reef again
until they're sexually
mature in about 20 years.
As October draws to a close,
things calm down
for the inhabitants.
The birds and migratory
fish move offshore.
The adult turtles return
to their feeding grounds.
After four months
of binging,
the whale sharks have
big round bellies,
and are ready to move on.
The young males will head
back to the Arabian Gulf.
They still have time before
they reach adulthood
and will likely return
next year.
The large female
that's been feeding here
is about 30 years old
and reaching maturity.
She may never return
to this reef.
She'll mix with the older
sharks of the Arabian Gulf,
looking for a mate.
Once she's mated,
she's likely to disappear
into the ocean depths
to have her young.
Though exactly where she'll
go and what she'll do
is still largely unknown.
The giants leave the reef,
taking with them the many
mysteries of their lives.
Only when the monsoon again
stirs up the reef
will they return and grace
the waters of Oman once more.
***
***
***
