All language subtitles for BBC Blue Planet Revisited 1of2 A Sharks Tale 1080p HDTV x265 AAC MVGroup org_Subtitles01.ENG

Sharks - nature's perfect solution
to an underwater life.

They've been swimming in the oceans
for over 400 million years...

..and, as top predators,

play a vital role
in keeping our seas healthy

and productive.

But they're coming under
increasing pressure,

millions are hunted and killed
every year.

Never have sharks needed friends

more than they do today.

For three weeks, I've been
in the Bahamas for Blue Planet Live.

Watching,

monitoring,

and diving with one of the richest
shark populations on the planet.

I want to reveal why sharks
are thriving here

and find out if there are lessons
to be learned

from these crystal clear waters

that could help secure their future
elsewhere around the world.

Our blue planet is home to more than
a thousand species of shark...

..and their cousins, the rays.

They come in a myriad of shapes...

..and sizes...

..and are found across
all of our oceans...

..from the tropics...

..to the Arctic...

..and into the deep abyss.

There are a few places where
the number and diversity of sharks

is unparalleled.

The Bahamas is one of them,

earning it the title of
shark diving capital of the world.

700 islands are scattered
over 84,000 square miles of ocean.

This location is unique -

perched on the edge of deep water,

where the seabed plunges
to a depth of 4,000 metres.

The meeting of shallow water
and deep, open ocean

leads to a profusion of life.

In winter, the resident
Caribbean reef sharks

and bull sharks

are joined by visitors,

bolstering the shark
and ray population to 78 species.

In 2011, the Bahamas were declared
a shark sanctuary,

making it illegal to fish for
or kill any species of shark.

These protected waters offer me
a unique chance

to get close to
these amazing top predators...

..and to see first-hand
what it takes

to have a healthy, thriving
population of sharks.

Within seconds of coming down here,

I'm greeted with
one of the most dazzling displays

you'll ever see underwater.

There's probably two or three
different sort of shark

at this location,
but the dominant kind

is going to be
the Caribbean reef shark.

And I can already see at least 20
of them here in the water around us.

I guess the first question that
people would ask would be,

isn't it dangerous, isn't it risky
to be surrounded

by this many apex predators?

And I have to say,

I feel just as comfortable
being in here,

surrounded by all these
extraordinary animals,

as I would do going for a walk
with a pack of poodles.

These animals are so good
at sensing their environment,

they know what's prey
in the water around them,

and it's not us.

They may well swim in close
but at the last second,

they just bank away.

They could not be less interested,

and the statistics about sharks
prove that's true.

Around the world, you're more likely
to be killed taking a selfie

than you are to be killed
by a shark.

In fact, statistically speaking,

the chance of being killed by a cow,
a deer or even a vending machine

is higher than the risk posed
by one of these.

Sadly, this abundance of sharks
is not typical

across all of our oceans.

This is not a sight that you get to
see just anywhere.

So, around the world,
we human beings are taking

at least 100 million sharks
from the world's oceans

every single year.

In some places, sharks have
declined by over 90%.

And in the time it'll take
for you to watch this programme,

over 11,500 will be killed.

It's a number that simply
cannot be sustained.

If it carries on like this,

then our children will not
have the opportunity

to dive in seas like this,

surrounded by these
stunning predators.

The Bahamas isn't the only place
to offer protection to sharks.

Today, a total of 17 sanctuaries
have been created around the world,

covering over
7.5 million square miles.

But this still amounts
to only 5% of our oceans.

Sharks need more help,

and if we don't give it to them,

much of the life in our oceans
will suffer.

As apex predators,

they remove
any sick or injured animals,

keeping fish stocks healthy.

Animals below them in the food chain

are kept in check.

And removing sharks would unbalance
whole ecosystems.

Over 3 billion people depend on
the ocean for their livelihoods.

It's essential we protect sharks
for our sake

as well as theirs.

And a vital step towards this
is combatting the reputation of fear

that many sharks still hold.

I always had a passion
for the ocean.

I fell in love with scuba diving.

I fell in love with everything.

It was a calling, I think.

Cristina Zenato left her homeland
of Italy over 20 years ago,

heading for the Bahamas.

Ever since, she's become
an advocate for sharks.

And two decades of diving
at one site,

off the island of Grand Bahama,

has convinced her that these animals
are a long way from being

mindless killers.

Cristina is known locally
as the Shark Dancer...

..and this is her stage.

I love that there is a busy silence.

It is the most peaceful
and calming moment of my day.

My babies are Caribbean reef sharks.

I love watching their behaviours

and their interactions.

They appear to me as different

as any other human being
that I encounter.

Some of them are more dominant.

Some of them are shy.

And some seemingly seek out
a closer encounter with Cristina.

The first time that shark
settled in my lap...

..and every time,
she settles in my lap,

and I feel her weight over my legs,

that is the most amazing feeling...

..and there's nothing, to this day,
that beats that.

You can feel everything
about the shark.

You can feel that it's a living,
breathing creature

that is aware of her surroundings,

that is aware
of what I am doing to her,

that is aware of my touch.

And the suit might actually have
a nice feeling to their skin.

These sharks are 8ft long.

I could never force an animal
of that size

to do anything or to sit anywhere.

It's their decision to come in,

it's their decision to stay,

it's their decision to go.

There is a total disconnect
from humans to sharks.

We can swim in the ocean with sharks
in a way that you could never

walk around on the snow
with a polar bear following you.

We have to make that connection
with the sharks,

understanding they
are way, way less dangerous

than many creatures out there.

Cristina's unique relationship
with sharks

allows her to do something
quite extraordinary.

She can take out fishing hooks
that are caught in their mouths.

Over the years,
she's removed more than 300 hooks.

We must change our ways,

because we need to protect
the oceans

and we need to protect the sharks.

And when you reach that message,

then you have a victory.

A greater understanding
of these misunderstood creatures

can undoubtedly help sharks.

And with such a diverse and healthy
population on its doorstep...

..the Bahamas has long been at the
forefront of global shark research.

The Bimini Biological Field Station,

or Shark Lab,

has been increasing our knowledge
of sharks and rays

for the last 29 years.

Heading this institute is
Matt Smukall,

who's had a passion for
the marine world

for as long as he can remember.

MATT: My first memories were
snorkelling in the Florida Keys.

Growing up, I always had an affinity
and a connection with, you know,

spending pretty much every weekend
and all summer in the ocean.

My favourite group of animals are
the sharks.

That's what originally brought me
to the Shark Lab,

that's what makes me enjoy
waking up every day

and doing this job.

The Bimini Shark Lab
started in 1990.

Right now at the Shark Lab,
we're studying everything from

southern stingrays to bull sharks,
tiger sharks,

lemon sharks, hammerheads,

but we take it from
a very ecosystem-driven model,

where we want to understand

everything that's going on
around Bimini

and how that's impacting
these big sharks.

One of the biggest and most
impressive species,

and the focus for a number
of Shark Lab studies,

can be found a stone's throw
from the heart of a busy marina.

These are bull sharks...

..drawn in by the scraps
discarded from fishing boats.

They spend much of their lives
in murky estuaries...

..so this clear water gives me
a unique opportunity

to see them up close,
and Matt a chance to learn more

about this little understood
species of shark.

I'm here on the bottom
of the harbour

and, as you can probably see,

I'm absolutely surrounded
by bull sharks.

This is an opportunist
that has a very wide array

of different kinds of prey,

so they'll feed on fish, on rays,
on birds at the surface,

on dolphins, they'll even bite
through the shells of turtles.

Now, all the sharks that I'm seeing
around me at the moment

are females, I haven't seen
a single male.

And they're quite big in the belly.

Why the warm waters
of the Bahamas attract

these large, slightly rotund females

has long been a mystery.

One Matt and his team from Shark Lab
are hoping to solve.

But to do that, they first have
to catch one.

To go ahead and catch, say,
a big female bull shark,

what we'll do is drop a baited hook,
throw it right in,

and they pretty quickly will
normally take the hook.

All right. On, on, on.

Hooking the bull shark
is the easy part.

As soon as they start running around
with the balls and the rope,

this is a bit of a dance between
the person bringing it in

and the shark.

We have to be very careful

cos they are not expecting to be
caught and handled by humans.

In order to help, number one,

for human safety
but also for shark safety,

we'll put a tail rope on.

That helps to secure the shark
to the boat.

Quick! Quick!

INDISTINCT CHATTER

With the shark safely harnessed
and calm,

the team can take the measurements

and assess the shark's condition.

And one of the most crucial jobs

is to find out
her reproductive state...

..using a very familiar method.

Ultrasound.

I think there's something
right there.

You can see it moving
slightly there.

That looks like the pup.

Over 50% of the females that
we catch are actually pregnant.

They have paired uterus,

so we check both sides.

And we're going to try to count

the number of pups that we can see,

the size of pups in both sides,

to get a better understanding
of her offspring litter.

After ten months, bull sharks
give birth to up to 13 pups.

These fully-formed pint-size sharks

are then left to fend
for themselves.

Now that we've confirmed
she's pregnant,

we're going to go ahead
and let her go on her way.

Give her a push.

All right, nice job.

At the end of the procedure,

it's great to be able
to give that shark a push.

We're blessed here
with beautiful, clear water

and we can always observe the shark,

basically follow her to make sure
that she's swimming strong

and that she's doing well.

And it's not just
the visiting bull sharks

who are carrying
the next generation.

Many other species
found in the Bahamas

are also pregnant.

It's thought that the warm waters
and rich feeding grounds here

help raise the shark's metabolism
and speed up gestation.

MATT: We know a lot about sharks
but there's so much more

that we still need to understand.

We still don't even know some of
the basic reproductive biology,

some of their life history things,

and these are all very important
for conservation.

This is what's really
going to help us manage

the next generation of sharks.

And it's managing
this next generation

and the habitats that are
essential to their survival

that's vital to maintaining
a healthy population of sharks.

This tangled mass of roots
is the mangroves.

It's an environment that
changes constantly

with the tides throughout the day.

And provides the perfect spot
for baby marine animals

to hide out in.

I'm joining Clemency White
from Bimini Shark Lab

to see how these mangroves
are key to the success of sharks

in the Bahamas.

Whoa! Look at that!

Yep, they're all waiting for us.

Baby sharks!

That's absolutely incredible.

These are lemon sharks.

And they've been studied by Clemency
and her fellow researchers

for over 30 years.

It looks like they want to be fed.

Yeah, we actually have
a little bit of squid

if you want to give it a go.

I...I would genuinely love to.

So, Clemency, how old are the sharks
we're looking at here?

Most of these sharks are
in their first few years of life.

So the majority of them will be
maybe two or three years old.

And some of those larger sharks
you can see

are maybe four or five.

So this is a refuge.

This is an area that's pretty much
only accessible

to these guys at high tide.

So that small, narrow walkway
that we walked in,

bigger sharks can't use that.

What sort of things
are they taking shelter from?

The biggest predator of juvenile
lemon sharks is actually

lemon sharks themselves,
adult lemon sharks.

So they're cannibalistic?
Yes, they are cannibalistic.

And also other large sharks,
so maybe bull sharks,

other species like that.

So this genuinely is a nursery,

it's a place where the youngsters
are safe from other...

Oh! That went right between my legs.

Yeah. I should be wearing a
cricket box or something. Um...

Are you OK?

THEY LAUGH
No!

Seriously, they're all making
a beeline

straight between my legs.

This would be a disaster if

all the things I've done in my life

and I was to get savaged
in the goolies by a baby shark.

Well, they must like you.

That one there's a decent size.

Yeah, so they'll be pretty loyal to
the mangrove that they were born in

until they're about 13 years old,
when they sexually mature.

Then they'll also come back to give
birth here as adults.

So they really rely on
those mangroves

for their entire life cycle.

What are the main threats
to mangroves in the Bahamas?

So, a lot of places, even in Bimini,

we see the mangroves are being
removed to facilitate bigger hotels,

bigger resorts,
and that in itself means

that these pups will still be born
in the same place,

they'll still be using
the same areas,

but they won't have that
same security from the larger fish.

So, lose the mangroves and
you lose the lemon sharks? Yep.

It may not look like any other
nursery you've seen before,

but you can see how vital
this environment is

to these rather wonderful and
surprisingly cute animals. Mm-hm.

All over the world,
baby sharks and rays seek refuge

in mangroves, seagrass
and estuaries.

Throughout their lives,

sharks need a whole variety
of ocean habitats...

..and protecting these is essential

if shark numbers are to bounce back.

Most sharks take many years
to reach sexual maturity.

Female great white sharks
need a whopping 33 years

before they can breed.

This, combined with their tendency
to produce just a few offspring,

means that shark populations are
extremely vulnerable to overfishing.

Right now, sharks are being killed
at a staggering rate.

They're deliberately caught
for food.

And accidentally caught in nets
or long lines

set for other species.

They're also harvested
in their millions for their fins,

to make shark fin soup -

a delicacy that's seen shark fins
sell for $650 a kilo...

..fuelling a cruel, wasteful trade,

which sees the rest of the shark
being thrown back into the sea...

..often still alive.

A third of all shark species are now
threated with extinction.

And this is being driven
by human activities.

But all is not yet lost.

There is hope.

And it comes from the fact
that these sharks

can be worth more alive than dead.

I'm heading 12 miles north
of Grand Bahama

to a site of global importance.

This could well be the best
shark dive in the whole world.

And what happens here is key
to securing the future of sharks

right across the world.

Whoa! Great hammerhead! Amazing.

Look at that. Powering straight in.

That is just extraordinary.

Drawn to
the warm, productive waters,

this is also the best place
in the world to see tiger sharks.

A tiger shark is unmistakable
in form.

It has the dappling running down
its sides,

which gives it its tiger name.

They'll feed on just about anything
they can find in the water.

And with those teeth, they can even
go through the shell of a turtle.

This is absolutely dazzling.

I don't know which way to look!

Tiger sharks, great hammerheads,

lemons, bull sharks, reef sharks.

It's the world's greatest safari,

it just all happens underwater.

Here and throughout the Bahamas,

sharks are drawn in with food

so tourists can reliably
get close to them.

Feeding of sharks
is a hotly debated topic.

there's people who think
that it's a bad idea

and might, potentially,
change the behaviour of sharks,

and I can totally see that,

but there's no doubt that
shark tourism here in the Bahamas

is incredibly important.

Each year, 20,000 people come to
the Bahamas to dive with sharks...

..making it the largest shark diving
industry in the world.

Shark diving here in the Bahamas

is worth an estimated $114 million
every year to the local economy.

Unquestionably, the sharks are worth
more alive than they are dead.

And that's hugely important

for the survival
of these extraordinary animals.

INDISTINCT CHATTER

All across the world,

shark tourism is fast becoming
a thriving industry -

not just for dive operators,

but boat drivers, hotels,
restaurants,

and bringing much-needed income
to shark hot spots

from all over the world.

I came from Philadelphia today

to swim with the sharks.

It was just invigorating.

It's a whole 'nother world
down there.

I'm from Argentina.

It was a long trip but it's amazing.

It's estimated that well over
half a million people

come to watch sharks every year.

Not only are sharks gaining
more advocates,

but they now hold
an indisputable monetary value.

And this will certainly help
to secure their future.

Shark conservation is something
that will require human effort

for many years to come.

And right here in the Bahamas,

there's a very special project
that's training up

the next generation
of shark champions.

Marine biologist Jillian Morris
has set up Sharks4Kids.

A charity to show children
across the Bahamas

that sharks are something
to celebrate,

not to fear.

I really believe that the best way
to change the way people see sharks

is to let them get in the water.

We take kids out to see sharks

and a lot of them are very afraid.

They don't want to get off the boat,

they don't want to step off
the beach,

and we get them to put a mask
and a snorkel on,

and we kind of ease them in.

And then they're snorkelling around

and they're seeing the sharks
and the rays up close

and realising they're not
trying to attack them,

that they're actually
really beautiful animals.

It's really incredible to see
students go from being terrified

and not wanting to get in the water,

to we're having to drag them out -

"We've got to go.
It's time to go home."

And to see that transition happen
right in front of you,

very quickly, is really,
really powerful.

The Bahamas is a shark sanctuary,

which is incredible and has set
a standard around the world

for shark conservation,
shark diving, shark science,

and so it's vital to have
the locals involved at all levels,

from kids to adults,

to protect the future
of this sanctuary

and the sharks here in the Bahamas.

While places like the Bahamas
offer protection

when the sharks are here...

..once beyond the invisible boundary
of the sanctuary,

sharks are immediately vulnerable.

Knowing where they go in
this vast, featureless landscape

is essential if we're to offer
them protection.

A few miles off the coast of Andros,

the endless blue is interrupted...

..by a naval buoy.

This lone beacon is a big draw
for passing travellers...

..providing shelter
for schools of fish...

..which attract the hunters.

Top of the food chain out here
are these -

silky sharks.

They get their name from
the silky sheen of their skin.

So little is known
about the migrations

of these open ocean drifters.

When shark biologist
Tristan Guttridge

heard rumours of this location,

it was an opportunity for him
to try and uncover these secrets,

which might just help protect
these threatened sharks.

There's nothing that gives me
more energy

than being in the water with sharks.

These silky sharks, they're a
completely different type of animal.

There's just something about them
that, you know,

brings them closer
and draws them in to you.

They have this curious,
bold personality

and it is a bit intoxicating.

And I love it.

But this inquisitiveness
is this shark's Achilles heel.

Silkies are in trouble globally.

And, in fact, silky sharks are the
second-highest caught shark species

in the world.

Industrial fishing often
uses floating objects,

working just like the naval buoy,

to attract an aggregate fish
like tuna

in the open ocean.

But they don't just attract tuna.

Every year, hundreds of thousands
of silky sharks

get accidentally caught.

I see the evidence of the pressures
that these animals are under

from the hooks in the mouths

and the leader wire
that's coming out of it,

you can see these sharks
are...they're in trouble.

They've got a lot to deal with
out in the open ocean.

Tristan wants to catch a shark

in order to attach a tracker,

which will reveal,
for the first time,

where these curious sharks go.

One method that we can use
to catch silkies is

that you can actually bend the top
of the tail over

and it sends them into this kind of
bizarre trance-like state.

And if you turn them upside down
at the same time,

then they're almost playing dead,
they're just out.

It's not fully understood why,

but many shark species enter
this trance-like state

called tonic immobility
when upside down,

enabling the team to tether
the shark next to the boat.

INDISTINCT SPEECH

A satellite tag
is fixed to its dorsal fin.

Every five minutes, this tag will
record important information,

including depth, light level
and water temperature.

After 30 days,
it'll pop to the surface

and start sending a stream of data
to Tristan.

TRISTAN: There's nothing more
exciting than the few days

when we know a tag is going to pop

as to where it's going to pop.

It's very important that we learn
more about their migration patterns,

their population structure,

in order to try and put management
measures in place

to improve their conservation.

They deserve to be on this planet.

Like us and like anything,
they deserve to be here

and we, as humans,
should be responsible.

So it is critical that we learn
more about these animals

and it's critical
that we protect them.

Tristan's tags have shown that these
sharks not only traverse oceans...

..but dive down to feed at depths
of over 400 metres.

Showing that if we want
to protect sharks,

we need to look after
every part of our oceans.

Satellite tags
are now being deployed

on many different species of sharks

and they're revealing
some incredible journeys.

The greatest distance ever recorded

was by a great white shark
named Nicole,

who swam from South Africa
to Australia

and back again -

a staggering 12,000 miles
in just nine months.

While understanding where
these top predators go is important,

another vital piece
of this conservation puzzle

is understanding why they go.

Just off the coast of Bimini
in the Bahamas,

there's a dive site that,
for a few months each year,

provides a close encounter

with one of our most iconic
and well-known migratory sharks.

This is the only place
in the whole world

where you can reliably see
great hammerhead sharks.

So we have dozens of sharks
around us.

Most are like this one here.

It's a nurse shark.

And the reason they have this name
is that when they're feeding,

they make a sucking noise,

kind of like a baby
when it's nursing,

when it's feeding.

You can see that they're quite
content lying on the bottom.

They can pump water
through their gills

and they don't have to swim
constantly in order to breathe,

like many other sharks do.

But this creature that's heading
towards us now,

that really is the main event.

It's a great hammerhead.

There are at least three of them
around us right now.

And while the nurse sharks
are quite dopey

and just hanging out on the bottom,

this is a far more targeted
predator.

There is nothing else quite like
a great hammerhead shark.

The shape of the head,

the giant dorsal fin.

It's so unusual-looking

and, yet, so perfectly adapted
to its job.

Shaking the hammerhead
from side to side

as it moves along the bottom,

sensing the potential
moving muscles of its prey.

Perhaps the most incredible thing
about this

is that great hammerheads are
an endangered species.

There are very, very few of these
almighty sharks left

in the whole world.

And right now,
I think we have seven.

I don't quite know what to say.

I'm completely blown away.

These great hammerheads
are seasonal visitors,

spending the winter months here,

between December and April.

Many return year after year.

The scientists have at least
30 individuals

that they know by name...

..and not just by name,
but by personality

and character and behaviour.

And even in the short time
since I've been here,

I've been starting to get to know
the individual personalities here.

You might not think of a shark
as having a personality,

but they very much do.

Some of them are quite bold
and dramatic,

and others are real gentle giants.

This almighty great hammerhead here
is called Gaia.

She's a female.

And the largest that they see here.

What an absolute beauty!

I will never, ever get tired
of this.

Holy Moley!

HE LAUGHS EXCITEDLY

For five months of the year,

these hammerheads are seen
virtually every day.

But in April,
they suddenly disappear.

One female was tagged here
at Bimini.

She then headed north
to the coast of the Carolinas,

before turning south again,

ending up off the coast of Florida.

A journey of over 3,000 miles
in less than two months.

But what's causing these ocean
wanderers to travel so far

and so fast?

I'm taking to the air to find out.

This is Palm Beach, Florida.

It's a playground for the rich
and the famous.

But little do they know that
just off the coast

is one of the greatest gatherings
of large predators on the planet.

These are blacktip sharks.

Massing in their thousands

before migrating north
to their summer feeding grounds

off the coast of North Carolina.

It's these sharks that attract
a host of larger predatory sharks,

including the great hammerheads,

which travel from the Bahamas
to feast on this bounty of food.

I've joined Stephen Kajiura,

a professor at
Florida Atlantic University.

Each year, he takes to the air
to monitor the number of sharks.

Just a slick of sharks going on
all the way parallel to the coast.

That is absolutely fantastic.

They stand out so well against
the sandy bottom, don't they?

That's one of the reasons
we're so successful

with the aerial surveys here.

We have clear water,
a light, sandy bottom,

we're able to see everything.

And they're in nice and shallow.
They're nice and shallow.

They really make it easy for you,
don't they?

But all's not what it seems.

Stephen's long-term study has shown

that this spectacular migration
is changing.

And this could have serious
consequences.

I've been doing these aerial surveys
for the last nine years.

We've seen this decline
in the number of sharks

over the past nine years.

At the same time,

we've seen an increase
in the water temperature down here.

They have a very narrow
thermal tolerance.

They like water between about
21 and 25 Celsius.

And as water temperatures
keep rising,

we're getting fewer and fewer sharks
coming this far south.

Presumably the blacktips
that you've got here,

there are constant interactions
between them

and the larger predatory sharks

like the tigers,
the great hammerheads and the bulls.

How is that likely to be affected?

That's a really good question.

If you don't have these blacktips
sweeping down here

in the tens of thousands
every spring,

there's no food
for the big hammerheads

and these blacktips are not eating
all the bait fish.

And so, we don't even know
what might happen.

You know, these ecosystems

have remained pretty much unchanged
for millennia,

but they are dramatically changing
in my lifetime,

and where that will lead
we simply don't know.

The rate at which our seas
are heating up is accelerating.

And the effects of this warming
are now being felt

in every one of our oceans.

Sharks are under pressure
from all sides -

fishing, their habitats changing,

and now, in these protected waters,

their fellow sea creatures.

Recently, an unwanted visitor
has appeared in Caribbean waters.

This is a lionfish.

A predator that could eat
fish populations out of existence...

..threatening the future
of the resident sharks.

Ten years ago, I saw for myself

just what devastating predators
they are in their native waters

off Malaysia.

There's a small fish over here.

The lionfish has spotted it.

This could be trouble.

It's moving in.

Oh! Unbelievable!

Did you see the speed
of that strike?

Lionfish eat about 70 different
species of fish and invertebrate.

If it fits in their mouth,

they'll eat it.

It did it again.

This is just the most astounding
display of feeding

I think I've ever seen.

Such an elegant fish is,
unsurprisingly,

a favourite of the aquarium trade.

And in the 1980s, a few unwanted
pets ended up being released

in the seas off Florida...

..with devastating results.

In just over 30 years,
they've spread from coastal Florida

with alarming speed.

They're now found as far north
as New York

and south to Brazil.

This is the wrong fish
in the wrong place

and at the wrong time.

And it's threatening to unbalance
the already fragile system

upon which the sharks depend.

This is a growing problem

that people like marine biologist
Alex Fogg

are trying to find a solution to.

ALEX: The reefs have changed
actually quite a bit

since I first started diving.

I started diving about ten years ago
and in this area in particular,

lionfish weren't here yet.

When we first started seeing
lionfish on the reef

it was one here or one there,
but now you go to a reef site

and you can see upwards
of 100 lionfish.

I mean, they're here eating
everything.

It's like an all-you-can-eat buffet,
if you will.

They're not just voracious hunters,

they're prolific breeders too.

A female lionfish can lay more than
20,000 eggs every four days.

They can reach densities of
over 200 adults per acre of reef

and that quantity can hoover up
nearly half a million fish a year.

This is having a devastating effect
on an already fragile ecosystem.

But Alex has a plan.

You can't really catch them
on hook and lines.

There's really only one way to
harvest lion fish

and that's through diving
and harvesting with spears.

And all these fish
don't go to waste.

Lionfish are definitely one of the
most environmentally-friendly fish

that you can actually eat.

This is one fish that we want to
eat into extinction.

Hey, Chef. Got you a bunch of fish.
Right, man. Appreciate it.

Thank you very much. Thank you.

Alex hopes that by making
a commercial market

for these lionfish,
more will be caught...

..allowing reefs and sharks
to recover.

Ten years down the road from now,

lionfish are still going to be here.

Are they going to be at the numbers
that we have today?

I'm not sure. I think that if we can
just get lionfish to a point

to where the ecosystem can actually
deal with it,

or they find their space
in the ecosystem,

that's our best bet.

The market for lionfish
in restaurants is growing.

But to fully combat this invasion,

things are being taken
a step further.

Along the coast of America, locals
have created lionfish derbies.

The aim - to collect and remove
as many lionfish as possible.

Each fish is measured and prizes
are awarded for catching the most,

the biggest,

and the smallest lionfish.

Hundreds gather
to share in the prize...

..and eat the catch.

These derbies serve to
reduce numbers,

as well as raising awareness
of a fish

that threatens the ocean ecosystems
upon which the sharks rely.

INDISTINCT CHATTER

Our blue planet is defined
by its oceans...

..and if they are to stay healthy
and productive,

we need a healthy population
of sharks.

At present, sharks are being killed
faster than they can reproduce

and we're set to lose
some of our most iconic species

in the next 50 years.

But across the globe,

many people are working tirelessly
to uncover the secrets of sharks

in order to save them.

People are seeing sharks
in their true light

and starting to appreciate them

for the essential role
they play in our oceans.

There is still much work
that needs to be done...

..but, for now, there is hope...

..for our oceans are packed
with the ingredients for recovery.

The seas are full
of tiny, microscopic life

just looking for somewhere
to fix and make home.

This is the Sapona.

It was grounded here in a hurricane
many decades ago,

and ever since,
it's become a living reef...

..absolutely bursting with life.

So many fish.

So beautiful.

The superstructure
makes a perfect habitat,

places for them to hide
from predators.

And it's covered with encrusting
soft corals and fans.

All sorts of animals
take up shelter inside.

Oh, stingray!

It's like swimming through
the ribcage of an almighty whale

lying on the bottom.

Incredible.

This is the basis of the food chain
upon which sharks depend.

If we protect our seas then life
will bounce back in our oceans,

if we give it the chance.

The interconnectedness of our oceans
and their inhabitants

is intricate and far-reaching.

Sharks depend on the creatures
around them

as these creatures in turn

depend on the sharks.

They've been stalking our seas
for at least 400 million years.

I hope they've got a few million
more left in them yet.

The Bahamas are at the forefront
of shark research and conservation.

And lessons learnt here
now need to be applied

all across our blue planet.

The future of sharks
is in our hands.

And it's for us to decide where
this sharks' tale goes next.