Mediterranean Sea Oceans


Mediterranean Sea

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They cover two thirds of our planet.

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They hold clues to the mysteries of our past.

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And they're vital for our future survival.

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But the secrets of our oceans have remained largely undiscovered

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until now.

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I am with a shark.

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Yes, yes!

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Explorer Paul Rose is leading a team of ocean experts

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on a series of underwater science expeditions.

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For a year the team has voyaged across the world

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to build up a global picture of our seas.

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We are doing some pretty uncharted research here.

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That is psychedelically purple!

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We're here to try and understand the earth's oceans and put them in a human scale.

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Our oceans are changing faster than ever.

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I've never seen ice like this before!

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There's never been a better time to explore the last true wilderness on earth.

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Looks good,

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perfect!

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The team is about to explore the sparkling blue waters of the Mediterranean sea.

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The remnant of an ancient ocean,

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this temperate sea is now home to over 700 varieties of fish

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and almost 10% of the world's marine species.

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Surrounded by the continents of Europe, Asia and Africa,

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its coastline is one of the most densely populated in the world.

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And the human pressure on this sea

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is magnified by 100 million visitors each year.

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Most people think of the Med

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as a holiday destination.

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It's hot, sunny,

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there's nice sandy beaches,

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but it's an ecosystem under pressure.

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Western civilisation developed around these shores

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but now human activity is threatening to ruin this sea.

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The Mediterranean has been critically important for so many thousands of years

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but the evidence is there.

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The Mediterranean is a shadow

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of what it once was.

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The team is here to explore the profound effect that man is having

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on these endangered waters.

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Quite a bit of life here but no large fish.

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On this expedition,

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environmentalist Philippe Cousteau investigates the delicate balance of marine life here

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and tries to protect one of man's most feared predators.

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The great white shark is definitely the holy grail, so to speak.

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And to search for them here in the Mediterranean, just fantastic!

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You actually can't see a way out. It is like you're surrounded on all sides.

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Marine biologist and oceanographer Tooni Mahto braves treacherous caves

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for evidence of some of the greatest changes to have shaped this sea.

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This cave is like a time capsule.

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This was once all dry land.

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Maritime archaeologist Dr Lucy Blue

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explores how the Mediterranean gave rise to one of Europe's first super-powers.

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The sea is often seen as that big dangerous expanse of blue

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that stops people moving around,

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but the Mediterranean is quite the opposite.

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It was a super-highway for millennia.

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The expedition will begin at the centre of the Mediterranean,

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in the waters between Italy and the island of Sicily,

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the Straits of Messina.

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The team is here to search for a prehistoric creature

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that's increasingly threatened.

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One of the largest predatory sharks in the world

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but one of the most rarely seen,

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the six gill shark.

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Typically, they're found in about 2,000 metres

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or in 6,000 or 7,000 feet of water.

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We assume they ride up in the middle of the night to feed,

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and then return back to the depths before the day.

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To have them here in about 40 metres of depth

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where we can get down and see them is super-rare.

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There's only a few places in the world where they've been found.

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If he's successful,

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expedition leader Paul will be one of only a few people ever to encounter this shark.

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Filming this vulnerable creature

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could give us a chance to learn more about this deep ocean animal

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facing threats from fishing, pollution and habitat destruction.

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We tend to think that obviously they've been filmed and studied loads

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but they haven't, so when I realised a glimpse is a success,

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it really puts pressure on tonight's dive.

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This rare opportunity

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is because of the peculiar underwater geography here.

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The Straits of Messina are a bottleneck

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connecting two deep sea basins.

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Tides and currents create upwellings,

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powerful surges of turbulent deep sea water,

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that are forced up and through this shallow narrow channel,

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dragging up rare creatures normally only found in the depths.

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The danger is that with these big overfalls and upwellings,

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that I'll get drawn to the surface quickly

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and it could be that I could come all the way to the surface

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and I can't afford to do that because I'd get decompression sickness.

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I'd get the bends.

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And it can be serious enough that I can end up, you know, tonight,

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I could do that dive, 40 metres, get blown to the surface

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and be in a wheelchair the rest of my life.

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Adding to the risk,

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this dive has to be made at night around the new moon.

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There are only a few nights when conditions are right,

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with tides strong enough to pull the six gill up from the deep.

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At midnight, Paul heads out into the inky waters.

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He will head the dive team with Philippe as his stand-by.

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I think this is an absolutely incredible opportunity to see a six gill shark

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because we know so little about these animals

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and the more evidence that we can gather about what they're doing down there, the better,

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the better for us to understand them,

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and also the better for us to hopefully protect them.

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Right Paul's good to go?

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Down we go.

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Good luck, mate.

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We're moving pretty fast actually.

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There's a real sense of purpose.

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Sharks are crucial to the health of our oceans.

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The six gill is almost identical to sharks from 200 million years ago,

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a living fossil that offers an insight

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into our prehistoric sea life.

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There's a lot of activity down here, we're swimming like the blazes.

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The night dive reveals some of the sea's nocturnal marine species

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like the moray eel.

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Paul swims by something that could entice a six gill into the area.

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It's not a shark but it's a beautiful octopus.

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Octopus, as well as fish and small sharks,

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are part of the six gill diet.

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But no sign of our shark, I'm afraid.

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The rescue boat is tracking the divers' lights,

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but diving at night in a strong current is a worry for dive supervisor Richard Bull.

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No matter how many times we've checked it,

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I'm always thinking, "What haven't we spotted, what is gonna go wrong?"

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When things go wrong when you're diving, it's bad.

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You know what I think the worst thing is? A missing diver.

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Paul still hasn't seen a shark.

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He's swimming against an exhausting three knot current

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so he is rapidly using up his air supply.

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Hang on, we can't see them for a second. Let me, uh...

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Suddenly the rescue boat loses sight of the divers forty metres below.

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Paul, surface?

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Kill all your lights, kill all the lights.

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To avoid decompression sickness as they ascend,

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Paul and his team need to breathe the pure oxygen the rescue boat is carrying.

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If we can't find them, the O2 tanks that they need for decompression,

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that are hanging under the boat,

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won't be there when they come up, so it's very dangerous.

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Mike Kasic is in charge of communications.

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Paul, surface?

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Paul, surface?

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Yes, just reporting, we've started to leave the bottom.

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We've lost you, we've lost you. So I need someone with lights

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to shine them to the surface so that we can kind of track you, OK?

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Roger, Roger.

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Keep your lights shining up, Paul.

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At last through the gloom, the divers' lights are spotted.

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Let's get some oxygen. Oxygen is going in now,

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and we're right over the top of them.

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We can see the cylinders, thanks guys.

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You know your heart skips a beat for a second but we found them.

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The relief that the team is safe

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is matched by frustration that they failed to find the six gill shark.

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What a disappointment.

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We have just swum our little legs off.

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You know, a bit tired from the exercise

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but disappointed really, blimey!

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I felt that we would find him, really did.

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The next night at midnight Paul dives again.

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Right, we're picking up the pace again.

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But after another exhausting swim, the dive ends.

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No sign of our shark, sorry guys.

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The team is beginning to understand

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why sightings of this shark are so rare.

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I look at the size of the strait

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and the small area that we can cover,

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although it feels like a whopping great big area,

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I realise it's a needle in a haystack job.

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Got one chance left tonight.

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It's the last night of the new moon

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when the tide could bring the six gill shark up from the depths.

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So Paul has pushed his equipment to the limit

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to give himself as much time as possible underwater.

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I've got the biggest cylinders I can carry and swim fast with,

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pumped to the absolute max.

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This is our opportunity to learn something and help study them

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so it means a lot.

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Six gills aren't aggressive to humans

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so to increase his chances of attracting one,

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Paul is attaching a bait bag to his dive belt.

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It's not that that great lump of tuna attracts a shark to bite you,

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but it grabs a lump of tuna and heads off into the deep dragging you with it,

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and that's when you've got to be prepared to get rid of it.

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Survival, it's a strong instinct isn't it?

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At 1:30 in the morning, the final dive begins.

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I do have to tell you, Philippe,

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it's absolutely perfect.

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We've slowed down a bit because we've come across a John Dory.

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It's a fantastic looking fish.

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Identifiable by the dark spot on the side of its body,

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this fish is another food source for predatory sharks.

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But we've got no time to waste, that's for sure.

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What are you seeing down there, over?

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Communications with Paul have failed.

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No I've got nothing, I don't even hear you speaking.

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Unaware that Philippe can't hear him,

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Paul presses on with his search.

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But I can't see anything.

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Where's the shark?

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Come on, baby.

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Where are you?

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Paul is down to his last ten minutes of air

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when he gets a signal from one of his dive team.

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Oh, wow!

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Surface, Paul. Surface, Paul.

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I am with a six gill shark.

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Can you believe this?!

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This is one of the largest predatory sharks in the world.

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It's a rare encounter with a mainly solitary animal

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that spends much of its life at the bottom of the sea,

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diving to depths of 2,000 metres.

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Look at those eyes. He's got those great green eyes.

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The eyes of deepwater sharks like the six gill can reflect light,

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enhancing their vision

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and allowing them to see in the gloom of the deep sea.

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1, 2, 3, 4, 5, 6...

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yeah, there you go!

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Most sharks have evolved to have just five pairs of gills

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but the six gills on this shark

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make it similar to sharks dating from 200 million years ago.

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It's like swimming with a living dinosaur.

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The sixth gill is thought to help them breathe

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in the oxygen-depleted waters of the extreme depths.

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That's not the only primitive feature.

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Its teeth and the structure of the jaw

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mean it closely resembles fossils of sharks from the Jurassic period.

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Six gill sharks spend most of their life at extreme depths

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where they can't be reached,

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so rare film like this will help scientists to study them.

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Ah blimey, there he goes.

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Philippe still doesn't know what's happened

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but as the divers begin to ascend, contact is restored.

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OK Paul, surface. What did you see down there? Over.

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We're now, uh...

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slowly coming up to our first stop,

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but we've all got big grins!

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Paul, surface, uh...

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Confirm, did you see a shark?

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Did you see a six gill, over?

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Roger, Roger. Saw a six gill shark!

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And he was a beauty!

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And it was a wonderful experience,

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we were in contact for five or ten minutes.

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Five or ten minutes?!

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Of course, the five or ten minutes the comms were out!

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I began to wonder if we'd see him before we ran out of air.

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-That's brilliant!

-Guys, it was worth the effort,

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totally worth the effort.

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That is fantastic!

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Paul, my man, how was it?

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You'll never believe it.

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We just swam down and just when we were thinking,

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burning up too much air trying to find this,

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and then he just came straight in.

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Just as smooth and as easy as you like!

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Sharks play a crucial role as predators in our seas and oceans,

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weeding out the sick and injured,

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but numbers are decreasing rapidly.

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Later in the expedition, the team will investigate

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how another shark could be at risk in this fast-changing sea.

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The Mediterranean is famous for its clear blue water,

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but that could be a sign of its vulnerability.

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Clear water indicates low levels of plankton,

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a crucial source of food in the sea.

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So Paul and oceanographer Tooni are using a secchi disc,

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a standard oceanographic tool, to measure the clarity of the water.

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-OK, ready?

-Yeah.

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In nutrient-rich waters the disc would disappear within a few metres.

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There we go.

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So there's nine.

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-Still seeing it?

-Yeah, totally.

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Eleven.

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That's the end of it, we can't go any deeper!

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-It's as clear now as it was at one metre.

-That's amazing.

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The clearer the water, the less plankton there is.

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That means we're in very low nutrient conditions.

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That is essentially why the Mediterranean is so blue.

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There's no microscopic plant or animal activity

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which means there's nothing to suck the light out of the water column.

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The Mediterranean has some of the lowest nutrient levels of any sea.

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This restricts how much can live here,

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as there's a limited amount of food,

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making it a delicate ecosystem

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particularly vulnerable to human activity.

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To find out just what marine life the Med is capable of supporting,

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the team's heading twenty-five miles south-west of Sicily,

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to one place that should be full of life -

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an enormous underwater volcano.

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It's 8:30 and we're on site.

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We've travelled all night and woke up this morning

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to see that we were in position and we've found the summit of the volcano

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which is right under the boat right now.

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Ferdinandea is over four hundred metres high

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and has a base that measures 750 square kilometres.

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Its tip is just eight metres from the surface.

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Many volcanoes were created

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as a result of the Mediterranean's tectonic plates colliding during its formation.

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Some breached the surface to form islands,

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which is exactly what happened to Ferdinandea in the 19th century

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as this contemporary painting depicts.

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It turns out when it was up, in 1831, it was actually a proper island.

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It was 60 metres high and something like four kilometres circumference,

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just under three miles round.

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But it turns out that it only lasted six months, just magma,

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and it just all quickly turned to ash

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and a few big seas and rain and general weather,

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and it demolished the top and once it got low,

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the sea knocked it back.

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Ferdinandea is now completely underwater once again,

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one of thousands of seamounts around the world

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which are magnets for marine life.

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So the team goes to find out what's living here.

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This volcano was created at the collision point

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of the African and European plates.

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Check out the ridges.

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It's very strange how there's a rippling effect

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in the black volcanic basalt.

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The ridges are caused by the speed of the water current

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that passes over them.

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This fertile volcanic sand

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allows the millions of microscopic plant and animal larvae that float in the open sea, to grow here.

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Seamounts are biodiversity hotspots

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because they provide organisms with a place to land and settle

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in an otherwise featureless flat ocean.

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As deep water hits these underwater mountains,

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it rises, bringing nutrients from the seabed,

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creating a rich feeding ground.

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These places, they've become like an oasis

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because they've got such deep waters all around us

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and this thing coming right up in this beautiful light zone

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attracts an abundance of life.

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Marine life uses seamounts as habitats, as spawning grounds,

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even as stepping stones while it travels around the sea.

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Lucy and environmentalist Philippe

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should find the summit teeming with life.

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There are lots of small schooling fish which is a good sign.

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Oh, and a sea urchin!

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Sea urchins just love all the algae that grows in here.

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But it soon becomes apparent something crucial is missing.

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Quite a bit of life here but no large fish.

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There's no sign of the open water fish

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like sardines, tuna and grouper that should be here.

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This is essentially an artificial reef in a big void space

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so all the little fish come here because they've got places to hide.

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And the little fish then attract the big fish

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but it also attracts the fishermen,

0:23:520:23:54

so I'm not surprised to see not a lot of big fish here in this area

0:23:540:23:59

because most likely the fishermen come here frequently.

0:23:590:24:03

Fishing has been an integral part of Mediterranean culture

0:24:050:24:09

for thousands of years.

0:24:090:24:10

Until recently, it was a largely sustainable industry.

0:24:100:24:14

However, since 1970 fishing in the Med has increased by almost 50%.

0:24:160:24:23

Conservationists now warn the entire sea is endangered.

0:24:230:24:29

The problem with the Med is because technology has advanced so swiftly

0:24:290:24:33

in the past 50 or 60 years,

0:24:330:24:35

and because it's such an enclosed area,

0:24:350:24:38

this is the place where the technological advances are going to have the most impact.

0:24:380:24:42

That impact is particularly felt

0:24:460:24:49

by an iconic species of the Mediterranean -

0:24:490:24:52

the Atlantic blue fin tuna.

0:24:520:24:55

They're pretty incredible animals.

0:24:550:24:58

They're fast, one of the few fish that are warm-blooded,

0:24:580:25:00

they're very complex, very interesting animals,

0:25:000:25:03

they're ocean-roaming all over the world,

0:25:030:25:05

and they're very highly prized.

0:25:050:25:07

The value of the estimated total blue fin tuna catch in the Med

0:25:090:25:13

is around £400 million.

0:25:130:25:15

This has triggered the rise in industrial fishing.

0:25:150:25:19

Philippe and marine biologist Tooni are heading off to investigate

0:25:220:25:26

one of the more recent developments in the harvesting of this sea -

0:25:260:25:30

a tuna farm.

0:25:300:25:31

It almost looks like a kind of rubberised pen

0:25:340:25:37

you'd see at an amusement park for people to go splash around in.

0:25:370:25:41

This is going to be full of tuna.

0:25:410:25:43

And ironically enough,

0:25:430:25:45

this is pretty much the only place I'm going to see such large schools.

0:25:450:25:49

-Any more.

-Any more.

0:25:490:25:51

There are now over 40 offshore tuna farms in the Mediterranean.

0:25:510:25:55

One, go for it.

0:25:550:25:58

Go for it.

0:25:580:25:59

Just look at the size of the net, it's huge.

0:26:050:26:09

In one way I was really looking forward to seeing these tuna because

0:26:090:26:13

I've never gotten to see them before in the wild.

0:26:130:26:16

-But seeing them swimming in circle after circle, over and over...

-Yeah.

0:26:160:26:22

20,000 to 30,000 tons are caught each summer in vast drag nets,

0:26:430:26:47

and towed to the tuna farms.

0:26:470:26:49

Well, these tuna have just recently been caught.

0:26:500:26:54

They'll be fed regularly to fatten them up

0:26:540:26:57

and then once they've reached a certain size,

0:26:570:27:00

about 200 to 300 kilograms,

0:27:000:27:02

they'll be taken to the mainland where they'll be shipped to Japan.

0:27:020:27:06

These wild blue fin tuna migrated here from the Atlantic Ocean

0:27:060:27:12

to spawn in the warmer waters.

0:27:120:27:15

They swim with their mouths open to force water over their gills.

0:27:150:27:19

If they stop, they suffocate.

0:27:190:27:21

Look at that blue stripe.

0:27:210:27:25

That's what gives them their name blue fin tuna.

0:27:250:27:27

It's a beautiful blue colour.

0:27:270:27:29

This farm operates within the law

0:27:320:27:34

but conservationists believe the high value of this tuna

0:27:340:27:38

means some fishermen are exceeding quota limits.

0:27:380:27:41

What's more, some are even flouting restrictions

0:27:410:27:44

on the size of the tuna they catch.

0:27:440:27:46

The fear is that more and more tuna farms are catching juveniles.

0:27:480:27:53

Yeah, this is depleting the population

0:27:530:27:55

before they even have a chance to procreate

0:27:550:27:58

and start the next generation.

0:27:580:27:59

And that's pushing the blue fin population here to the brink of extinction.

0:27:590:28:03

Scientists believe that as much as 20,000 tons of blue fin tuna

0:28:060:28:11

are caught illegally in the Mediterranean every year.

0:28:110:28:15

The Med's most iconic fish,

0:28:150:28:17

and the traditional fisheries it once supported,

0:28:170:28:20

are now close to collapse.

0:28:200:28:22

It doesn't just have an implication for the Mediterranean.

0:28:240:28:27

It has an implication for the Atlantic

0:28:270:28:29

because they're a migratory species.

0:28:290:28:31

For the survival of the Mediterranean economy

0:28:310:28:34

and survival of Mediterranean traditions

0:28:340:28:36

that have been in place for thousands of years,

0:28:360:28:39

you have to maintain a population of that species

0:28:390:28:42

and that isn't happening.

0:28:420:28:43

The exploitation of this sea is no new phenomenon.

0:28:460:28:50

Man's influence has been felt here for millennia.

0:28:500:28:54

Some of the greatest civilisations in our history

0:28:540:28:57

have used the Mediterranean to their advantage.

0:28:570:29:01

Maritime archaeologist Dr Lucy Blue

0:29:030:29:07

has worked in the Med for much of her career,

0:29:070:29:09

exploring how this sea is uniquely important

0:29:090:29:12

in the development of western civilisation.

0:29:120:29:14

You know this is where cultures developed, around these shores.

0:29:150:29:19

The sea, in this instance more than anywhere else in the world,

0:29:190:29:22

facilitated the communications and the development

0:29:220:29:25

of these civilisations.

0:29:250:29:27

The Romans ruled this sea over 2,000 years ago

0:29:280:29:32

and became one of humanity's first superpowers.

0:29:320:29:36

Lucy has brought the team to the Egadi Islands to the west of Sicily.

0:29:360:29:42

She wants to search the wreck of a Roman cargo ship

0:29:420:29:45

for any clues to what was being traded,

0:29:450:29:48

and how far these routes stretched across the Mediterranean.

0:29:480:29:52

It's 1st century BC so it's the early part of the Roman period

0:29:550:29:59

where they've just taken Sicily over

0:29:590:30:02

so it's about development and expansion.

0:30:020:30:04

They're going to dive to just one of hundreds Roman wrecks

0:30:060:30:10

that have been discovered in the Med,

0:30:100:30:12

clear evidence of the scale of traffic

0:30:120:30:15

around this sea in ancient times.

0:30:150:30:17

OK, so we're gonna moor up to the buoy that you can see over there

0:30:190:30:22

-where the other boat is.

-Yeah.

0:30:220:30:24

And there's a shotline there. It goes down to 12 metres

0:30:240:30:26

and basically that just slips down quite gradually

0:30:260:30:29

to about 24 metres.

0:30:290:30:32

Is that good? You're clear. Clear behind.

0:30:320:30:35

On your mark, clear.

0:30:350:30:37

The wooden structure of the shipwreck

0:30:450:30:47

has long since disintegrated.

0:30:470:30:49

What remains is some of the cargo it carried,

0:30:490:30:52

a mound of amphorae, enormous ceramic containers.

0:30:520:30:56

Just getting a first glimpse of the amphorae on the sea bed

0:31:020:31:06

and it's really quite remarkable,

0:31:060:31:09

and although I have worked on a number of shipwrecks over the years,

0:31:090:31:13

I have never actually seen such a large number of amphorae

0:31:130:31:17

concentrated in one spot.

0:31:170:31:19

The wreck dates from around the 1st century BC.

0:31:210:31:25

That's over 2,000 years old.

0:31:250:31:28

Now that's a fairly intact one, there.

0:31:420:31:46

But what were the Romans trading?

0:31:460:31:49

Shall I grab that end?

0:31:490:31:52

What have you got?

0:31:520:31:53

I've got 120.

0:31:560:31:58

It's huge.

0:31:580:32:00

From the shapes and the fact that they were lined with bitumen or pitch,

0:32:000:32:04

they likely carried wine.

0:32:040:32:07

Probably would have carried about 20, 25 litres of wine.

0:32:080:32:14

You can see the shape of them.

0:32:140:32:15

It's perfectly made to slot into the hull of a vessel.

0:32:150:32:19

This is how they would have stored them,

0:32:190:32:22

sort of one on top of the other in the hull of a Roman merchantman.

0:32:220:32:26

Having found out that these amphorae are likely to have carried wine,

0:32:280:32:31

Lucy now needs to look for any clues that might reveal who produced it.

0:32:310:32:37

There's one that has the names of the family that produced the wine.

0:32:370:32:42

"Papia".

0:32:420:32:44

Based in southern Italy,

0:32:450:32:46

the Papia family were a powerful dynasty of winemakers

0:32:460:32:50

who exported it around the Mediterranean.

0:32:500:32:53

It's likely that they were transporting them from Sicily

0:32:530:32:57

maybe even to north Africa.

0:32:570:32:59

This would have been part of the general trade in wine and olive oil,

0:32:590:33:05

garum - which is a fish paste -

0:33:050:33:08

that was being conducted around the Mediterranean at this time.

0:33:080:33:12

This is a record of a trade that linked two continents,

0:33:150:33:18

and the scale of this operation

0:33:180:33:21

shows how effectively the Romans established trading routes

0:33:210:33:24

around the Mediterranean.

0:33:240:33:26

There are about forty amphorae here,

0:33:260:33:29

but these are only a fraction of the original cargo.

0:33:290:33:32

There used to be about 400 to 500

0:33:340:33:37

but these have been taken by looters.

0:33:370:33:39

It's a big problem in the Mediterranean.

0:33:390:33:42

Treasure hunters have damaged and stolen

0:33:460:33:48

many of the rich but fragile historical remains

0:33:480:33:52

that scatter the floor of the Med.

0:33:520:33:53

To protect what remains of these amphorae,

0:33:560:33:59

this underwater archaeological site

0:33:590:34:02

is being monitored 24 hours a day by CCTV.

0:34:020:34:06

The pictures are fed to the nearby island of Favignana

0:34:130:34:16

where they're monitored by police.

0:34:160:34:18

Buon giorno, possiamo guardare?

0:34:180:34:21

-Prego.

-Grazie.

-What was that?

0:34:210:34:25

Just asked permission, want to have a little respect.

0:34:250:34:28

-Ooh!

-We've got some visitors.

0:34:280:34:30

There's Paul right in front of the camera. And there's Lucy.

0:34:300:34:33

I think this whole project is so unique,

0:34:340:34:36

the fact that they're very interested in the conservation of these relics.

0:34:360:34:40

It's kind of sad that they had to in the first place

0:34:400:34:43

but it's very cool that they do it.

0:34:430:34:45

Since CCTV was installed,

0:34:450:34:47

not a single Roman amphora has been stolen.

0:34:470:34:51

The cameras protect what remains of this valuable site,

0:34:510:34:55

a record of how the Mediterranean sea enabled civilisations to expand.

0:34:550:35:01

For the team's next mission,

0:35:070:35:09

Paul and Tooni are heading off to Mallorca

0:35:090:35:12

to look much further back in time.

0:35:120:35:14

They'll be diving underground to search for evidence of huge changes

0:35:140:35:19

which transformed the whole Mediterranean,

0:35:190:35:23

changes that helped bring people here in the first place.

0:35:230:35:27

Mallorca lies in the western Mediterranean.

0:35:370:35:40

Beneath the island's east coast is a vast network of flooded caves.

0:35:400:35:46

This cave system is connected to the sea

0:35:480:35:50

but Paul and Tooni must drive several kilometres inland

0:35:500:35:54

to reach the entrance.

0:35:540:35:56

In these flooded caves are unusual formations that you can only see,

0:35:570:36:02

apparently you can pick them up in the Bahamas and a few other spots

0:36:020:36:06

but this is a really rare opportunity to learn more about the Med.

0:36:060:36:12

It's probably the most dangerous diving we're gonna do on this!

0:36:120:36:15

Yeah, that's going to make me feel better. Thanks mate(!)

0:36:150:36:19

-Here we go.

-That looks like a cave.

0:36:250:36:27

Doesn't fill me with joy, it has to be said.

0:36:270:36:29

It doesn't look very inviting.

0:36:290:36:31

Paul and oceanographer Tooni will be searching for proof

0:36:310:36:35

of when Mediterranean sea levels dropped many thousands of years ago,

0:36:350:36:40

changing the coastline and creating the ideal conditions

0:36:400:36:43

for people to spread and settle.

0:36:430:36:45

They'll have to brave a perilous section of flooded caves

0:36:470:36:52

and though they're both trained cave divers, this is a dangerous task.

0:36:520:36:57

There's a definite sense within me that this is a risky dive.

0:36:570:37:01

As soon as you can't get to the surface,

0:37:010:37:03

there's a lot of opportunities for things to go wrong.

0:37:030:37:06

They are hoping to examine rare rock formations deep inside the earth.

0:37:090:37:15

The dive begins with a claustrophobic entrance way.

0:37:260:37:31

Here we go. The trick here, Tooni, is going to be head first for sure.

0:37:340:37:40

Just have to take our time as we go through this squeeze.

0:37:400:37:44

The visibility has gone to next to nothing.

0:37:450:37:48

Very, very, very tight indeed, this.

0:37:500:37:52

You couldn't possibly go through much smaller of a space.

0:37:520:37:57

One hand at a time, one hand at a time.

0:38:000:38:06

It goes down as well.

0:38:070:38:09

Tooni and Paul dive further and further down below ground

0:38:090:38:14

into the cave system.

0:38:140:38:15

Kind of a brutal start this, no visibility and very cold.

0:38:170:38:22

As they travel deeper into the network,

0:38:260:38:29

they reach a mysterious water haze.

0:38:290:38:31

Here we go, halocline coming up, Tooni, look.

0:38:340:38:37

This haze, or halocline, is caused by light rays diffracting

0:38:390:38:44

as they pass through the different densities of clearer fresh water,

0:38:440:38:48

and denser salt water.

0:38:480:38:49

It's the first sign these inland caves are connected to the sea.

0:38:490:38:54

I love the fact that you've got fresh water above

0:38:550:38:58

and sea water below,

0:38:580:39:00

and then you get this crazy kind of lime cordial effect

0:39:000:39:03

where the two meet.

0:39:030:39:04

I've never been able to SEE density before.

0:39:040:39:10

Physics in action.

0:39:100:39:12

Coming out of that halocline, look how clear it is now.

0:39:140:39:17

Oh, that is beautiful!

0:39:180:39:21

The divers emerge into the crystal clear water of an enormous cavern.

0:39:290:39:34

Wow, Tooni, look at the size of this room.

0:39:360:39:40

This is just incredible!

0:39:400:39:42

I'd always fancied being an astronaut

0:39:540:39:58

but maybe this is as close as I'm ever gonna get.

0:39:580:40:00

Instead of outer space,

0:40:000:40:02

it's like the cave divers use that word, "inner space",

0:40:020:40:05

and it's very true.

0:40:050:40:07

Deep inside the earth, they've found what they've been looking for,

0:40:110:40:15

spectacular sculptural rock formations,

0:40:150:40:19

that shouldn't even be here.

0:40:190:40:22

We've come underwater here, below sea level,

0:40:220:40:25

and yet we're seeing these stalagmites on the bottom

0:40:250:40:30

and the stalactites from the ceiling

0:40:300:40:32

which means that this cave was once dry

0:40:320:40:34

because those things only form in dry caves.

0:40:340:40:38

These majestic structures have formed over time

0:40:380:40:42

by mineral-rich water dripping into dry caves.

0:40:420:40:46

To find them in this flooded cave

0:40:460:40:48

is proof that the sea level was once much lower than it is today.

0:40:480:40:53

These rare bulbous formations around the stalactites and stalagmites,

0:40:560:41:00

found almost nowhere else on earth,

0:41:000:41:03

can reveal when the sea level changed.

0:41:030:41:06

This bulge was formed when the sea level was here.

0:41:060:41:09

Lapping water deposited minerals

0:41:090:41:12

which created this blancmange-like structure.

0:41:120:41:16

By dating these mineral deposits,

0:41:160:41:19

scientists can build up a chronological record

0:41:190:41:22

of changing sea levels in the Med.

0:41:220:41:25

Sea levels have been going up and down

0:41:250:41:27

over hundreds of thousands of years.

0:41:270:41:29

This evidence proves that 60,000 to 80,000 years ago,

0:41:340:41:38

the Mediterranean sea was shallower.

0:41:380:41:40

Lower sea levels exposed new ground

0:41:420:41:45

and created land bridges between islands.

0:41:450:41:48

This allowed early humans who'd migrated out of Africa

0:41:480:41:52

to move around the Mediterranean, settling on its coasts and islands.

0:41:520:41:57

This cave is like a time capsule.

0:41:580:42:00

It proves how much the Med has changed

0:42:000:42:02

and that's had a huge influence.

0:42:020:42:03

The Mediterranean has been host to humanity

0:42:090:42:12

for hundreds of thousands of years.

0:42:120:42:14

Today over 150 million people live around its shores.

0:42:180:42:21

That number almost doubles in the summer

0:42:210:42:24

with the influx of holidaymakers.

0:42:240:42:27

Pollution, fishing and coastal development

0:42:290:42:32

are putting enormous stress on these fragile waters,

0:42:320:42:35

threatening marine life.

0:42:350:42:37

Rare species are most likely to suffer.

0:42:400:42:44

And one of the Med's most endangered

0:42:440:42:46

is so elusive many are surprised to learn it's here at all.

0:42:460:42:51

Philippe wants to investigate

0:42:510:42:53

why the Mediterranean is home to one of our most feared predators,

0:42:530:42:58

the great white shark.

0:42:580:42:59

People think oh, Jaws,

0:43:080:43:10

sharks are these monsters of the ocean coming to eat us,

0:43:100:43:13

but sharks are critical to the health of the marine environment

0:43:130:43:16

because they're apex predators.

0:43:160:43:18

They have a perfect place in their ecosystem,

0:43:180:43:21

balancing and keeping it healthy.

0:43:210:43:23

They are...beautiful.

0:43:230:43:25

These great whites were filmed off South Africa.

0:43:280:43:31

They're most likely to be found there,

0:43:310:43:33

or off California and Australia.

0:43:330:43:36

The clear waters of the Med might seem an unlikely habitat for this predatory shark

0:43:360:43:41

because of the limited food supply.

0:43:410:43:43

But there have been rare sightings

0:43:450:43:48

to suggest the great white is living here.

0:43:480:43:51

This extraordinary footage was recorded ten years ago

0:43:540:43:59

by a fisherman on holiday in the Med with his son.

0:43:590:44:02

It shows a great white shark circling the fisherman's boat

0:44:050:44:09

before tearing chunks from a small fresher shark he'd caught.

0:44:090:44:12

But sightings like this are extremely uncommon.

0:44:210:44:25

There is some video of great whites in the past

0:44:250:44:28

but any evidence that we can gather

0:44:280:44:31

to prove that great white sharks live in the Mediterranean

0:44:310:44:36

would help us to protect these incredible creatures.

0:44:360:44:39

To investigate why great whites could be here,

0:44:410:44:44

the team is heading to the middle of the Sicilian channel,

0:44:440:44:47

to the tiny island of Lampedusa.

0:44:470:44:50

This must be him, he's headed right for us.

0:44:540:44:58

That is my man! All right, finally!

0:44:580:45:01

-Buon giorno!

-Good morning!

0:45:010:45:03

-How are you, man?

-OK, great!

0:45:030:45:06

They'll be working with patron of the Shark Trust

0:45:060:45:09

and world expert on great whites in the Med, Ian Ferguson.

0:45:090:45:13

We're ready for you.

0:45:130:45:16

Ian's been looking for the great white here for over fifteen years

0:45:170:45:20

and he's convinced there's a pattern to the occasional sightings.

0:45:200:45:24

Have the sharks that have been caught

0:45:240:45:26

in this particular month in this area just been pure one-offs,

0:45:260:45:30

or are they actually here for a reason?

0:45:300:45:32

And my longstanding hypothesis

0:45:320:45:34

is that the animals are here,

0:45:340:45:36

and the reason is to give birth.

0:45:360:45:38

The Sicilian channel is the only location

0:45:400:45:42

in the entire eastern Atlantic region

0:45:420:45:45

where both pregnant and new-born great whites have been sighted.

0:45:450:45:48

Yeah, we think it's about three...

0:45:480:45:51

Ian believes this could be one of only a few nursery areas

0:45:510:45:54

identified anywhere for these endangered sharks.

0:45:540:45:57

It's an area of great importance,

0:45:570:45:59

it's obviously a very important habitat for them

0:45:590:46:02

and we need to get to understand why is this area so important

0:46:020:46:05

and what can we do to protect the sharks.

0:46:050:46:08

So what might make this a suitable breeding ground?

0:46:110:46:14

The harbour is right there. The proposal is to come round here,

0:46:140:46:18

a deep dive there on the wall - you know, 40 metres -

0:46:180:46:21

to check out the habitat, really.

0:46:210:46:23

The idea behind this is that this could be potential for feeding,

0:46:230:46:29

-this is what great whites like to eat.

-Sure.

0:46:290:46:32

Tooni and Lucy dive to look for any evidence

0:46:360:46:38

that this might be a great white nursery.

0:46:380:46:42

Now keep your eyes peeled out there for large pelagics.

0:46:430:46:47

If we're going to see them anywhere, we should be seeing them here.

0:46:470:46:52

Compared to other parts of the Med,

0:46:530:46:56

the warm water of the Sicilian channel is rich in nutrients.

0:46:560:46:59

This should attract pelagic or open water fish,

0:46:590:47:03

as well as dolphins and turtles that great whites feed on.

0:47:030:47:07

Lucy, there's a shoal of damsel fish just here.

0:47:080:47:12

They're very, very territorial fish,

0:47:120:47:15

so this seems to be quite a productive area we're in.

0:47:150:47:19

Oh, that's a big grouper!

0:47:210:47:23

Bottom-dwelling fish like this

0:47:240:47:27

are a typical part of the diet of juvenile great whites.

0:47:270:47:30

Because this is such a great place for fish,

0:47:320:47:35

it's also a great place for sharks.

0:47:350:47:37

And there's further evidence to support Ian's theory.

0:47:390:47:43

This shallow shelf is typical of the habitat young great whites need.

0:47:430:47:48

It keeps away predators like blue and mako sharks

0:47:480:47:52

that don't hunt in shallow waters.

0:47:520:47:55

But at the surface, events take a turn for the worse.

0:47:580:48:02

I've just been to see the captain. There's gales forecast.

0:48:050:48:08

It'll be 25 knots-plus, which is...

0:48:080:48:11

you know, at sea, isn't the worst weather,

0:48:110:48:13

but for what we've got in mind, it's never going to work.

0:48:130:48:17

With the wind picking up,

0:48:190:48:22

it's urgent to get Tooni and Lucy back on board.

0:48:220:48:25

All divers, all divers, surface.

0:48:250:48:28

We need to get out of the water as soon as possible.

0:48:280:48:31

The wind's really picking up now, the wind's really picking up now.

0:48:440:48:48

So we've called Tooni and Lucy back early.

0:48:480:48:50

We've got the main engines running now.

0:48:500:48:53

We're going to get the guys in, and run for Lampedusa, fast.

0:48:530:48:58

The storm's an unwelcome delay to their investigation of the great white in the Med.

0:49:020:49:07

-It's a totally different sea out there, isn't it?

-Yeah.

0:49:080:49:11

It's like the North Sea and it's getting rougher by the minute.

0:49:110:49:14

Next day, the storm has subsided...

0:49:260:49:29

Keep pulling on yours, Philippe.

0:49:290:49:31

..and the team decide on a last, hugely ambitious attempt to gather direct evidence,

0:49:310:49:35

laying a bait trail of chum -

0:49:350:49:37

pulped oily fish - to try and attract a great white to the boat.

0:49:370:49:42

We're going to deploy the most fantastic shark cage on the planet,

0:49:420:49:46

get some people in there, chum and chum and chum.

0:49:460:49:50

See if we can find some great whites.

0:49:500:49:53

Everyone's aware it's a long shot.

0:49:570:50:00

They now only have a few days

0:50:000:50:02

to create a chum slick big and nasty enough to attract a great white.

0:50:020:50:07

-You got it?

-Yeah, bung it, bung it.

0:50:110:50:14

Give it a shake to start it off.

0:50:140:50:17

Bung it.

0:50:190:50:22

-Just revolting.

-It's horrible, isn't it?

0:50:220:50:25

Overnight, the fish obviously starts to deteriorate,

0:50:280:50:31

so I'm trying to just get the fish mashed up.

0:50:310:50:34

It'll be a very strong mix

0:50:340:50:35

and what we're trying to achieve is a very strong odour trail,

0:50:350:50:39

like a corridor for the sharks to follow right up to the boat.

0:50:390:50:42

That smell is totally revolting.

0:50:450:50:46

Great white sharks have a highly developed sense of smell.

0:50:480:50:52

With tiny holes in their snout, it's thought they can detect

0:50:520:50:56

minute drops of blood in water from up to three miles away.

0:50:560:50:59

-I'm going in.

-That's it. Speed is everything.

0:51:030:51:06

Although they have the reputation for being man-eaters,

0:51:060:51:09

great whites rarely attack humans,

0:51:090:51:12

but Philippe can take no chances

0:51:120:51:14

and uses the cage to keep shark watch underwater.

0:51:140:51:17

Man, it's rough down here!

0:51:170:51:19

If we get a hint of seeing a great white shark in the Med,

0:51:190:51:23

doesn't matter how uncomfortable we are.

0:51:230:51:26

Long day, long night.

0:51:350:51:37

We've just got to keep going

0:51:370:51:39

and we're doing everything we can to keep our chances high.

0:51:390:51:42

The whole team is going to be on watch

0:51:420:51:45

and we're just going to keep at it, all hands, 24 hours.

0:51:450:51:49

The team keeps chumming through the night

0:51:520:51:55

and the oily fish slick attracts a tantalising abundance

0:51:550:51:58

of sea life towards the boat.

0:51:580:52:01

It's just gone midnight and the chum slick is suddenly coming alive.

0:52:010:52:05

Here comes...

0:52:050:52:06

What's that, a flying fish?

0:52:060:52:10

These fish have long fins on their sides

0:52:100:52:12

which they use to fly above the water for around 50 metres

0:52:120:52:16

to escape from predators.

0:52:160:52:18

As well as flying fish, there are needle fish and a pelagic octopus.

0:52:180:52:24

Fantastic. Slick's working, then.

0:52:240:52:27

The conditions are right

0:52:270:52:29

and the smelly chum slick is buzzing with life.

0:52:290:52:33

Great whites often hunt at night, using their sense of smell

0:52:330:52:38

to locate their prey, so Philippe returns to the cage.

0:52:380:52:42

All right!

0:52:420:52:44

It is a little choppy,

0:52:440:52:46

but still good conditions and I'm not giving up hope.

0:52:460:52:50

The last sighting of a great white shark,

0:52:500:52:53

that we know of, in the Mediterranean,

0:52:530:52:55

occurred right around here about a year ago.

0:52:550:52:58

What's even more exciting is that the great white sighted

0:52:580:53:02

was a juvenile - only about five feet long -

0:53:020:53:05

which makes it a critical place for the great white shark.

0:53:050:53:10

So even the slightest sign of great white activity here

0:53:120:53:15

could be significant.

0:53:150:53:18

-We'll see, man. We've got all night, see what happens.

-Just keep going.

0:53:210:53:26

Yeah, it's all we can do.

0:53:260:53:27

With only a few hours left of the expedition, Ian is on dawn watch.

0:53:290:53:34

Then, as morning breaks...

0:53:360:53:39

Guys, we've got a chum bag pulled out.

0:53:390:53:42

One of our mesh bags, the red one, has been pulled out.

0:53:440:53:49

-That's great news, right?

-It takes a lot to do that.

0:53:490:53:52

-That's good news, that. Something's happening.

-Yeah.

0:53:520:53:55

So we have definitely had a shark respond to our chum?

0:53:550:53:58

It certainly wasn't those fish!

0:53:580:54:00

It's happening! Can you believe it?

0:54:000:54:03

Encouraged by the encounter,

0:54:050:54:07

the team tries everything to lure the shark back.

0:54:070:54:10

But as the expedition ends, the bite is the closest they get

0:54:190:54:24

to finding evidence of this endangered creature.

0:54:240:54:27

That's it!

0:54:300:54:31

It's a tantalising end to the trip.

0:54:320:54:35

Down a bit, mate.

0:54:350:54:37

But perhaps not such bad news for the shark.

0:54:370:54:41

Although it's a slightly sort of perverse way of looking at it,

0:54:410:54:44

one side of me is somewhat relieved that

0:54:440:54:47

the animals still remain so cryptic and so distant from us

0:54:470:54:50

that we're finding it, with all of our effort,

0:54:500:54:53

difficult to actually get them to come to us,

0:54:530:54:55

which is a shame for us, but possibly good news for white sharks.

0:54:550:55:00

We've only ever explored maybe 5% of our oceans,

0:55:030:55:07

and in a sense, I think that not finding the great white

0:55:070:55:11

is an extension of that mystery.

0:55:110:55:13

As the team have seen,

0:55:150:55:17

humankind is encroaching more and more on this sea.

0:55:170:55:21

The great white might not be able to avoid us for much longer.

0:55:210:55:25

During this expedition,

0:55:310:55:32

the Mediterranean has revealed some of its many secrets.

0:55:320:55:36

Oh, wow, can you believe this?!

0:55:360:55:40

The team has uncovered proof of this sea's dramatic past

0:55:420:55:46

and explored the long relationship

0:55:460:55:48

humans have had with the Mediterranean.

0:55:480:55:52

The expedition has also shown how humans

0:55:520:55:55

can put untold pressure on a delicate ecosystem.

0:55:550:56:00

Quite a bit of life here, but no large fish.

0:56:000:56:04

I'm not comfortable with always using the word "fragile"

0:56:040:56:07

around the earth because I don't think it's a fragile planet.

0:56:070:56:11

I actually think it's very, very robust,

0:56:110:56:13

but the Mediterranean sea - because it's surrounded by so much input

0:56:130:56:18

and there's so much stock being taken

0:56:180:56:21

and we're asking so much of this small sea -

0:56:210:56:24

that I think anybody that came and experienced what I just have,

0:56:240:56:28

I think it would totally reset people's thinking and attitudes

0:56:280:56:33

towards the Mediterranean sea.

0:56:330:56:35

This sea is many things to many people -

0:56:370:56:41

a holiday destination,

0:56:410:56:43

a historical treasure chest, a food resource for millions.

0:56:430:56:47

It's a rich and diverse environment

0:56:490:56:51

with a precious history and a vital future, both of which need securing.

0:56:510:56:56

Next time,

0:57:060:57:08

the team braves one of the most hostile environments on the planet -

0:57:080:57:12

the Arctic Ocean.

0:57:120:57:13

They dive beneath the vanishing ice cap

0:57:150:57:19

and explore how changes to this frozen sea

0:57:190:57:22

are threatening the ocean's life, and the rest of the planet.

0:57:220:57:26

We are completely dependent on the stuff that keeps the planet cold.

0:57:260:57:31

Subtitles by Red Bee Media Ltd

0:57:500:57:53

E-mail [email protected]

0:57:530:57:56

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