0:00:02 > 0:00:05They cover two thirds of our planet.
0:00:07 > 0:00:11They hold clues to the mysteries of our past.
0:00:11 > 0:00:15And they're vital for our future survival.
0:00:18 > 0:00:23But the secrets of our oceans have remained largely undiscovered.
0:00:23 > 0:00:25I am with a six-gill shark.
0:00:25 > 0:00:28Yes! Yes!
0:00:28 > 0:00:32Explorer Paul Rose is leading a team of ocean experts
0:00:32 > 0:00:36on a series of underwater science expeditions.
0:00:36 > 0:00:43For a year the team has voyaged across the world to build up a global picture of our seas.
0:00:43 > 0:00:46We are doing some pretty uncharted research here.
0:00:46 > 0:00:49That is psychedelically purple!
0:00:49 > 0:00:51We're here to try and understand
0:00:51 > 0:00:54the Earth's oceans and put them in a human scale.
0:00:56 > 0:01:00Our oceans are changing faster than ever.
0:01:00 > 0:01:04I've never seen ice like this before!
0:01:04 > 0:01:10There's never been a better time to explore the last true wilderness on Earth.
0:01:23 > 0:01:27We're about to see one of the most remarkable creatures in the Indian Ocean.
0:01:27 > 0:01:29And this is the only way we can get there.
0:01:29 > 0:01:35This is a dive of a lifetime. It's not going to be very easy.
0:01:40 > 0:01:47This expedition will explore the third largest body of water on Earth, the Indian Ocean.
0:01:48 > 0:01:55More than 6,000 miles wide, it covers 13% of the world's surface.
0:01:55 > 0:02:01It's home to 5,000 species of fish, many unique to this sea.
0:02:05 > 0:02:07But it's an ocean on the edge.
0:02:07 > 0:02:13Global pressures like climate change and overfishing threaten to push it to a tipping point.
0:02:20 > 0:02:26The team has come to the western Indian Ocean to find out what effect these changes are having.
0:02:28 > 0:02:35Environmentalist Philippe Cousteau is the grandson of ocean pioneer Jacques Cousteau.
0:02:35 > 0:02:41He'll investigate the threat to one of these waters' greatest predators.
0:02:41 > 0:02:48By removing them in such large numbers, that has drastic impacts on all the other species underneath it.
0:02:48 > 0:02:52Maritime archaeologist Dr Lucy Blue will experience the treacherous
0:02:52 > 0:02:56effects of the unpredictable currents here.
0:02:56 > 0:03:00She hit this reef behind us and then broke her back.
0:03:00 > 0:03:03And marine biologist and oceanographer Tooni Mahto
0:03:03 > 0:03:08will explore what can be done to save this pristine wilderness.
0:03:08 > 0:03:14What we're looking at here is almost the Indian Ocean equivalent of a garden centre.
0:03:17 > 0:03:22The expedition begins off the southern coast of Mozambique.
0:03:22 > 0:03:28Paul and Tooni have come here in search of the largest population of manta rays in the world.
0:03:31 > 0:03:36We actually stand a chance here of being right alongside
0:03:36 > 0:03:40or underneath or right with these huge mantas.
0:03:40 > 0:03:44- Some of them are about five or six metres.- Eight metres.
0:03:44 > 0:03:46I'm going for a giant eight-metre one.
0:03:46 > 0:03:49Eight metres across - that's a huge fish!
0:03:49 > 0:03:52It's very exciting indeed.
0:03:52 > 0:03:55The team's been brought here by a mystery.
0:03:58 > 0:04:0476% of the manta rays here have been attacked by sharks, attacks that
0:04:04 > 0:04:06should have decimated their numbers.
0:04:06 > 0:04:09So, how have they survived?
0:04:10 > 0:04:12Ready, ready, ready.
0:04:16 > 0:04:18It's a beautiful sight.
0:04:24 > 0:04:27The visibility is a little bit murky.
0:04:27 > 0:04:31It means there's a chance this water is very plankton-rich.
0:04:35 > 0:04:37Here, close to the edge of the continental shelf,
0:04:37 > 0:04:44the plankton is fed by nutrient-rich water welling up from the deep.
0:04:44 > 0:04:50It helps support an entire eco-system, everything from giant potato groupers...
0:04:52 > 0:04:54..to poisonous lionfish.
0:04:58 > 0:05:02Tooni spots a sign that they're in the right place to find mantas.
0:05:02 > 0:05:07This is a very particular environment, a cleaning station.
0:05:07 > 0:05:09The clue?
0:05:09 > 0:05:11These tiny fish.
0:05:11 > 0:05:13There's a whole load of small cleaner wrasse that
0:05:13 > 0:05:18are waiting here, the very small black-and-white-striped fish.
0:05:19 > 0:05:25And they're waiting here until the mantas actually come here, so they can go up to their skin
0:05:25 > 0:05:30and pick off all the parasites, which apparently feels really good on the mantas as well.
0:05:30 > 0:05:32They seem to like the sensation.
0:05:32 > 0:05:38So it's a bit like going for hair and make-up and a massage at the same time.
0:05:41 > 0:05:44Looking for mantas.
0:05:44 > 0:05:48I'm waiting for one to just sneak up on us from behind!
0:05:49 > 0:05:52I keep imagining that I'm seeing them coming out of the gloom.
0:05:54 > 0:05:57Tooni, there's a manta. Come on!
0:05:57 > 0:06:01Oh, oh, oh! Oh, my goodness!
0:06:01 > 0:06:03Oh, my goodness!
0:06:03 > 0:06:05It's a whopper, Tooni!
0:06:06 > 0:06:09That is beautiful!
0:06:14 > 0:06:17Oh, my! So elegant.
0:06:18 > 0:06:24The largest of the ocean's rays, mantas weigh up to one and a half tonnes.
0:06:24 > 0:06:29Yet they fly gracefully through the water, using their wing-like fins.
0:06:30 > 0:06:31They are bizarre-looking.
0:06:32 > 0:06:37The horns at the front that gave them their name, the devil ray.
0:06:40 > 0:06:45The horns can unroll to funnel food into the manta's mouth.
0:06:46 > 0:06:52As the water passes through, spongy tissue traps the plankton they feed on.
0:06:55 > 0:06:58But this one shows no sign of a shark bite,
0:06:58 > 0:07:04so it provides no clue as to how so many mantas survive these attacks.
0:07:04 > 0:07:06And time has run out.
0:07:07 > 0:07:12We're both low on air, both got 50 bar, so we need to leave the bottom.
0:07:12 > 0:07:18Unfortunately, in man versus manta, the manta gets to win this one.
0:07:27 > 0:07:29There was a whopper behind Tooni!
0:07:29 > 0:07:33And then we didn't see any more.
0:07:34 > 0:07:40They have located a manta cleaning station, but they still haven't found what they're looking for.
0:07:40 > 0:07:44The manta that we did see didn't have any injuries at all.
0:07:44 > 0:07:49And it's actually specifically the injuries that I'm really interested in going and having a look at.
0:07:50 > 0:07:54With the light fading, they decide to try again in the morning.
0:08:00 > 0:08:04Next day, weather and sea conditions are perfect.
0:08:07 > 0:08:09But Tooni's not.
0:08:09 > 0:08:11Oh, God!
0:08:14 > 0:08:15SHE RETCHES
0:08:15 > 0:08:21I'm feeling really ropey, and I think I've got a stomach bug or something.
0:08:23 > 0:08:26Being sick underwater could be deadly.
0:08:26 > 0:08:29With the masks we're using, which are full-face masks,
0:08:29 > 0:08:32where the air comes from is right down in the front.
0:08:32 > 0:08:35And if someone was to throw up in them,
0:08:35 > 0:08:40there's a reflex inhalation, isn't there, when you breathe in?
0:08:40 > 0:08:46That reflex inhalation, which can't be controlled, would bring stuff back into the throat.
0:08:46 > 0:08:50There's a chance of being brought to the surface unconscious.
0:08:50 > 0:08:52She's experienced enough to know
0:08:52 > 0:08:53that she can't just push it.
0:08:53 > 0:08:57I think you should probably go, and I'll sit this one out.
0:08:59 > 0:09:03I know we saw the mantas yesterday, but we didn't
0:09:03 > 0:09:06see specifically what it was we came to see.
0:09:06 > 0:09:08I've read about this for years.
0:09:08 > 0:09:11I would be really interested
0:09:11 > 0:09:14to see the mantas and the cleaning behaviour.
0:09:15 > 0:09:19It's just frustrating, really frustrating.
0:09:22 > 0:09:27It's all up to Paul to find out what helps the injured mantas survive.
0:09:35 > 0:09:38This time, the elusive mantas turn up straightaway.
0:09:38 > 0:09:40Look at this!
0:09:45 > 0:09:47Look at him go!
0:09:47 > 0:09:51Effortless, but incredibly fast.
0:09:54 > 0:10:01What's really fascinating is that the whole life on this reef changes when the mantas come and go.
0:10:01 > 0:10:04All the attention is focused on them.
0:10:08 > 0:10:11There's a shark bite right there at the very back.
0:10:12 > 0:10:17A shark attack like this is often fatal.
0:10:18 > 0:10:23Oh, there's another one. This one has two great bites out of the back end.
0:10:23 > 0:10:28No-one's sure why so many of these mantas have been attacked by sharks.
0:10:28 > 0:10:32But the location of their wounds is less of a mystery.
0:10:32 > 0:10:36The manta's eyes are on the side of its head, leaving a blind spot
0:10:36 > 0:10:41directly behind, exactly where the sharks have taken a bite.
0:10:41 > 0:10:43I'm gonna stay still here
0:10:43 > 0:10:45to see if he'll come my way.
0:10:47 > 0:10:49Here he comes.
0:10:51 > 0:10:54Just look how big he is compared to me!
0:10:56 > 0:10:59And look just how well he moves.
0:10:59 > 0:11:02And here's some cleaning. Can you see the cleaning going on?
0:11:02 > 0:11:05That's what I'd dreamed we would see.
0:11:16 > 0:11:23The yellow butterfly fish and moon wrasse clean the wounds, removing dead and infected tissue.
0:11:27 > 0:11:30It's like pulling into a hospital and having your wounds dressed.
0:11:30 > 0:11:32Stops infections forming.
0:11:41 > 0:11:45More and more mantas arrive to have their wounds treated.
0:11:46 > 0:11:50This could be why they're so resilient to shark attacks.
0:11:54 > 0:11:58A cleaning station with fish that target the shark wounds.
0:12:03 > 0:12:05Behaviour that's rarely seen.
0:12:20 > 0:12:23Really, really marvellous.
0:12:23 > 0:12:30Then here comes this great manta. Just kind of came over me. Shark wounds on the back end,
0:12:30 > 0:12:33and was smothered in cleaner fish. It was a great dive.
0:12:35 > 0:12:38The cleaning station is a perfect example
0:12:38 > 0:12:44of how complex interactions make the world's marine eco-systems function.
0:12:44 > 0:12:52Every living thing here is vital to this ocean's health, right up to its most extreme predators, sharks.
0:13:00 > 0:13:07Next, the team will investigate what's happening to shark populations in this ocean,
0:13:07 > 0:13:12because sharks have turned from the hunters into the hunted.
0:13:12 > 0:13:18Up until now they have reigned supreme, and we are totally decimating their numbers.
0:13:18 > 0:13:23And, as the apex predator, by removing them in such large numbers out of these areas,
0:13:23 > 0:13:26that has drastic impacts on all the other species underneath it.
0:13:28 > 0:13:32Overfishing means shark numbers are plummeting.
0:13:32 > 0:13:40Estimates suggest that each year as many as 73 million sharks are fished worldwide.
0:13:40 > 0:13:4426 shark species are now listed as critically endangered.
0:13:47 > 0:13:53Along this coast, shark fishing has grown dramatically over the past few years.
0:13:53 > 0:13:57Philippe and Lucy have come onland to find out more.
0:13:57 > 0:14:00This is Pomene in Mozambique.
0:14:00 > 0:14:05Lucy and I are here to try and figure out kind of exactly what's happening and why and how.
0:14:05 > 0:14:10We're here early because this is when they take their boats out to check their lines.
0:14:10 > 0:14:15Little is known about shark fishing in this part of the world.
0:14:15 > 0:14:17It's a unique chance to investigate it first hand.
0:14:19 > 0:14:21How many sharks does he catch?
0:14:21 > 0:14:24HE SPEAKS IN LOCAL LANGUAGE
0:14:28 > 0:14:32Between three and seven.
0:14:32 > 0:14:35- Wow. So is he from here? - He's from Vilanculos.
0:14:35 > 0:14:39- Oh, he's from Vilanculos. And he came here five years ago to fish?- Yeah.
0:14:39 > 0:14:43But Vilanculos is several hours away.
0:14:43 > 0:14:49These fishermen are not from here, and the locals have no history of shark fishing.
0:14:49 > 0:14:51This is something new.
0:14:53 > 0:14:59These people have come or been brought here deliberately, within
0:14:59 > 0:15:04some structured organisation, to specifically do this type of fishing.
0:15:04 > 0:15:06And that is most unusual.
0:15:07 > 0:15:14The fishermen head out to check their three kilometres of line with its 65 separate hooks.
0:15:14 > 0:15:19This one boat can land up to 1,000 sharks in a single year.
0:15:33 > 0:15:37The fishermen return with their catch.
0:15:38 > 0:15:39Two males.
0:15:39 > 0:15:41Little blacktip reef shark.
0:15:45 > 0:15:48Both sharks are extremely young.
0:15:50 > 0:15:54These aren't anywhere near sexual maturity.
0:15:54 > 0:16:00They're little baby reef sharks, maybe two years old, a year old maybe.
0:16:00 > 0:16:04Sharks don't start reproducing until they're several years old.
0:16:04 > 0:16:08When they do, most have few offspring.
0:16:08 > 0:16:11So catching young sharks like these is particularly worrying.
0:16:11 > 0:16:15The worst thing for me is the fact they're so small, you know.
0:16:15 > 0:16:18They haven't reached maturity.
0:16:18 > 0:16:23So there's no reproduction. That's the end of this particular lineage.
0:16:23 > 0:16:28But why is this industry growing so fast?
0:16:30 > 0:16:34The fins are the most valued part of the catch,
0:16:34 > 0:16:41the essential ingredient in the Chinese delicacy shark-fin soup,
0:16:41 > 0:16:44demand for which is growing rapidly.
0:16:52 > 0:16:55It's pretty barbaric when you see it here now.
0:16:55 > 0:16:57- It's- BLEEP.- Look at this.
0:16:57 > 0:16:59This little pile of fins for...
0:17:00 > 0:17:02..soup.
0:17:02 > 0:17:04The waste is disgusting.
0:17:07 > 0:17:11The only reason they sell the meat is because they can get a few cents for it.
0:17:11 > 0:17:13It's worth nothing.
0:17:13 > 0:17:17The only reason they're doing this is for those fins.
0:17:18 > 0:17:20And there's a huge incentive.
0:17:21 > 0:17:24How much will they sell those fins for?
0:17:24 > 0:17:30The fish, big one, bigger than the fish today,
0:17:30 > 0:17:36only the fins, they can make 50, 60.
0:17:36 > 0:17:3850, 60, just the fin?
0:17:39 > 0:17:46In a country where most people live on less than 1 a day, six sharks can provide a year's income.
0:17:46 > 0:17:49There you go. Merry Christmas.
0:17:49 > 0:17:52The fishermen show off a recent catch.
0:17:52 > 0:17:55This pile of fins is worth a small fortune.
0:17:57 > 0:18:01- Where do they go now? - They go to Maputo,
0:18:01 > 0:18:02and then they go out.
0:18:04 > 0:18:08According to the fishermen, the big money means that regulations
0:18:08 > 0:18:12to control the export of fins are being ignored.
0:18:12 > 0:18:14So the trade flourishes.
0:18:14 > 0:18:21Across the globe each year, millions of sharks continue to be wiped out.
0:18:21 > 0:18:26It's scary when you think that so few individuals can come into a community like this
0:18:26 > 0:18:29and take out so many animals.
0:18:29 > 0:18:34Over 1,000 animals a year come out of this little cove!
0:18:34 > 0:18:36- This is not big!- Four boats.
0:18:36 > 0:18:42- It's shocking.- And when you think what's going on around the other shores of the Indian Ocean...
0:18:44 > 0:18:48And, to add insult to injury, shark fin has no flavour.
0:18:48 > 0:18:52They have to flavour the soup with chicken broth, for God's sakes.
0:18:52 > 0:18:55It's ridiculous.
0:18:55 > 0:18:57It's absolutely ridiculous.
0:18:59 > 0:19:07They've discovered that along this coast shark fishing is an organised industry driven by fat profits.
0:19:07 > 0:19:12It's just one part of a global trade that's decimating species
0:19:12 > 0:19:15and disrupting the balance of life throughout the Indian ocean.
0:19:21 > 0:19:24But overfishing is not the only threat.
0:19:26 > 0:19:31A changing climate will impact the ocean, altering its weather patterns.
0:19:33 > 0:19:39These are dominated by heat transfer to and from the sea.
0:19:39 > 0:19:42But this is a complex process we know little about.
0:19:46 > 0:19:51To try and find out more, the expedition will take part in a huge project
0:19:51 > 0:19:56run by scientists around the world, including the British Met Office.
0:20:01 > 0:20:06They head north to the equator, where the heating effects of the sun
0:20:06 > 0:20:10have a powerful impact on the ocean and on the weather.
0:20:14 > 0:20:20There's no clearer example of the link between the oceans and the climate than a tropical storm.
0:20:35 > 0:20:37The energy in the Indian Ocean!
0:20:37 > 0:20:39There it is, coming right at us!
0:20:39 > 0:20:41Maybe a bit more than we ideally want right now.
0:20:41 > 0:20:44- I don't know.- It's definitely coming. It's a proper good
0:20:44 > 0:20:47pile of rain, and the sea's picking up a little bit.
0:20:49 > 0:20:52The heavens have opened. It's bucketing down.
0:20:52 > 0:20:55The captain advises that this thing rolls quite a bit.
0:20:55 > 0:20:59It's not unusual to have two feet of water swilling around on this deck.
0:21:06 > 0:21:10Storms are powered by the constant exchange of heat and moisture
0:21:10 > 0:21:12between the ocean and the atmosphere.
0:21:13 > 0:21:17So, understanding these processes is vital.
0:21:20 > 0:21:22I've got goosebumps!
0:21:27 > 0:21:30Look at the sea. Look what the rain does to the sea.
0:21:30 > 0:21:33It's knocked down. It's fantastic.
0:21:35 > 0:21:39The global project to gather data on the forces driving our weather
0:21:39 > 0:21:41is based around one vital piece of equipment.
0:21:43 > 0:21:45I've gotta make sure that it's in there.
0:21:45 > 0:21:48I can see it's been opened by customs.
0:21:48 > 0:21:54You never know with these things. It's supposed to be yellow and expensive-looking.
0:21:55 > 0:21:59This is the Argo float, a robotic buoy, designed to gather
0:21:59 > 0:22:04readings on temperature and salinity from the depths of the ocean.
0:22:04 > 0:22:09How this thing works is it descends to 1,000 metres and then comes back up again.
0:22:09 > 0:22:14Uploads all of its data and then sinks again.
0:22:15 > 0:22:21This will be one of a vast network of floats transmitting their data
0:22:21 > 0:22:25to satellites to build up a dynamic picture of the ocean.
0:22:28 > 0:22:32The plan is to launch it into an area that's poorly covered by
0:22:32 > 0:22:36Argo floats to help plug a gap in the survey network.
0:22:39 > 0:22:43I should hear at some point...
0:22:43 > 0:22:44ARGO FLOAT BEEPS
0:22:44 > 0:22:46There we go, one. That's working.
0:22:51 > 0:22:56Now it's turned on, it's programmed to be deployed in just six hours.
0:22:56 > 0:22:58Here we go!
0:22:58 > 0:23:03I can hear it. It runs for five or ten seconds and then stops.
0:23:03 > 0:23:06You can't put enthusiasm into this unless
0:23:06 > 0:23:09you have some empathy and some interest in it, and I do.
0:23:09 > 0:23:12I really do. I mean, this is a... Hang on.
0:23:13 > 0:23:15Yeah, there it goes again!
0:23:18 > 0:23:21En route to the launch site, the £6,000 worth of equipment
0:23:21 > 0:23:26must be kept upright while it makes contact with the satellite network.
0:23:26 > 0:23:29What sort of information is being collected in this?
0:23:29 > 0:23:33It's temperature, salinity and depth.
0:23:33 > 0:23:35And when it comes up, it's also position as well.
0:23:36 > 0:23:40The data will help scientists worldwide
0:23:40 > 0:23:44to improve climate-change prediction and tropical-storm forecasting.
0:23:44 > 0:23:48So how much longer do we have before it needs to be in the water?
0:23:48 > 0:23:50It's six hours from when we turn it on. It's now 10,
0:23:50 > 0:23:52so four hours, 50 minutes.
0:23:56 > 0:23:59But the journey is taking longer than expected.
0:24:01 > 0:24:06It would suit us better if we could be on the eastern side of the target area, where it's deeper.
0:24:06 > 0:24:09A bit twitchy about... Everything seems to happen just once.
0:24:09 > 0:24:16The plan is for Paul to be in the water when the float is launched to make sure it deploys correctly.
0:24:18 > 0:24:21All systems go, and we've got 45 minutes to go.
0:24:22 > 0:24:27It took a little bit longer to get here than we thought.
0:24:27 > 0:24:30As you can see, I'm not dressed for the dive yet!
0:24:30 > 0:24:33But we just can't afford to be loafing at the moment.
0:24:35 > 0:24:40Far from land, with no reference points to gauge position and depth,
0:24:40 > 0:24:45dive safety supervisor Richard Bull is concerned about Paul's dive into the big blue.
0:24:45 > 0:24:50What I'm worried about is sinking down without noticing it.
0:24:50 > 0:24:53Because you get to a point where
0:24:53 > 0:24:56you're so deep, you can't see the surface,
0:24:56 > 0:24:59you can't see the bottom, you can't see that way and you can't see that way.
0:24:59 > 0:25:02You can't tell which is up and which is down.
0:25:02 > 0:25:06Yeah. It'd be easy to do on this dive, because I'm just watching that yellow float.
0:25:08 > 0:25:11We're getting late, we're going to miss it.
0:25:11 > 0:25:14The float is timed to begin its first descent in just a few minutes.
0:25:16 > 0:25:19Lucy is in charge of the crane.
0:25:19 > 0:25:21You know yourself, when handling a crane...
0:25:21 > 0:25:24"You know yourself, when handling a crane"!
0:25:24 > 0:25:27I have to point out, this is the first time I've done any crane-handling!
0:25:32 > 0:25:34I'm really, really concerned
0:25:34 > 0:25:37about it hitting the side of the boat, though.
0:25:39 > 0:25:41Wahey! Oh, God!
0:25:42 > 0:25:48A tiny bump against the metal hull could dent the casing, creating a weak spot that might
0:25:48 > 0:25:55rupture deep below the surface, where the water pressure will reach 200 times atmospheric pressure.
0:25:55 > 0:25:56Five minutes, five minutes.
0:26:01 > 0:26:06The rolling of the boat is also a problem for Paul.
0:26:06 > 0:26:11I'm just swimming out of the way here because our dive boat is right there.
0:26:15 > 0:26:20I don't want to bang myself into it, and he's going to have to start positioning soon.
0:26:20 > 0:26:24And that propeller's going to start going round, so I want to get it out the way.
0:26:24 > 0:26:25Woo!
0:26:25 > 0:26:29I have to make a note of a number of things so the Met Office have an
0:26:29 > 0:26:34understanding of the sort of basic sea state when the Argo's launched.
0:26:34 > 0:26:40Knocks and bangs against the side of the vessel? Apart from the initial swing I induced, I think it was fine!
0:26:40 > 0:26:45God, I'm shaking a bit, actually, because I don't want to mess it up. You've only got one go.
0:26:45 > 0:26:47You can't take two on this one!
0:26:48 > 0:26:52But the descent time comes...
0:26:52 > 0:26:55It's still there. Look!
0:26:55 > 0:26:57..and goes.
0:26:57 > 0:26:59That's...
0:26:59 > 0:27:01Oh, no!
0:27:02 > 0:27:05If it doesn't go down in the next minute or so,
0:27:05 > 0:27:07there could potentially be a problem.
0:27:07 > 0:27:09It's not ready just yet.
0:27:12 > 0:27:14It hasn't sunk yet.
0:27:17 > 0:27:20Finally, the launch begins.
0:27:20 > 0:27:22Five, four,
0:27:22 > 0:27:26three, two, one!
0:27:31 > 0:27:34Wow, there it goes!
0:27:35 > 0:27:37I'm waving goodbye to it on its
0:27:37 > 0:27:39four-year mission.
0:27:47 > 0:27:54If it works, it'll help scientists gain a better understanding of the Indian Ocean monsoons.
0:28:02 > 0:28:07It goes down 1,000 metres and then 2,000 metres
0:28:07 > 0:28:11and comes to the surface repeatedly
0:28:11 > 0:28:15up to 150 times, for four years solid.
0:28:15 > 0:28:18I can just see it. Look!
0:28:18 > 0:28:20Just pick her out.
0:28:22 > 0:28:28In ten days, it should surface and transmit back to base for the first time.
0:28:28 > 0:28:33Only then will the team know if the launch has succeeded.
0:28:33 > 0:28:34It's gone!
0:28:48 > 0:28:52We're now under way for the southern coast of Zanzibar, the south-western tip of Zanzibar.
0:28:52 > 0:28:56A brilliant feeling. You just mention the name Zanzibar to me and I want to go there.
0:28:58 > 0:29:01The team takes the opportunity to go ashore.
0:29:17 > 0:29:20It's such a public game. Such a great game.
0:29:20 > 0:29:22And I think we have a winner.
0:29:29 > 0:29:33- Thank you very much.- Thank you. Very happy with that.
0:29:39 > 0:29:41With coastal development and over fishing,
0:29:41 > 0:29:44human pressure on this sea is increasing.
0:29:44 > 0:29:48So, for the next mission, the team wants to see how that's impacting
0:29:48 > 0:29:51one of the ocean's most precious eco-systems.
0:29:51 > 0:29:56Environmentalist Philippe heads out with Lucy,
0:29:56 > 0:30:00to check on the health of the Indian Ocean's world famous coral reefs.
0:30:09 > 0:30:13Worldwide, coral reefs are vital to the lives of a billion people,
0:30:13 > 0:30:17who rely on them for food and income.
0:30:17 > 0:30:22And they're home to a vast variety of marine life.
0:30:22 > 0:30:25But the reefs may have reached a tipping point.
0:30:28 > 0:30:32I have to be honest with you, I'm a little disappointed.
0:30:33 > 0:30:40I'm not seeing the abundance of fish life that I'd expect here.
0:30:40 > 0:30:45It just seems a little light to me and that's kind of disappointing.
0:30:45 > 0:30:52For three generations, Philippe's family has been documenting this ocean's threatened habitats.
0:30:54 > 0:31:01Having grown up with images of my grandfather's films and my father's films, back in 1948.
0:31:01 > 0:31:07You look at that, even though it's in black and white, it's like an amazing forest.
0:31:07 > 0:31:09Just richness is unparalleled.
0:31:09 > 0:31:12You go back to those places today and it's just a desert.
0:31:12 > 0:31:18Coral reefs are disappearing at such a scary rate.
0:31:20 > 0:31:26Across the globe, 25% of coral reefs are under threat.
0:31:26 > 0:31:29Philippe spots what's attacking this reef -
0:31:29 > 0:31:32one of its most voracious predators.
0:31:32 > 0:31:35Wow, look at that!
0:31:35 > 0:31:37That's a crown-of-thorns, right?
0:31:39 > 0:31:41It's enveloping that piece of coral.
0:31:43 > 0:31:48A crown-of-thorns starfish eats the coral alive.
0:31:48 > 0:31:54They can eat up to 16 or 17, maybe even 18 or more,
0:31:54 > 0:31:57square feet of coral reef a year.
0:31:57 > 0:32:01You can see right there,
0:32:01 > 0:32:04they take their stomach literally and turn it inside out
0:32:04 > 0:32:05when they get on the coral
0:32:05 > 0:32:10and then start to eject all these stomach enzymes all over it.
0:32:10 > 0:32:13And it oozes out all over the coral and liquefy it
0:32:13 > 0:32:15and then they just suck it up.
0:32:15 > 0:32:18Kind of nasty!
0:32:18 > 0:32:22Recently, a hundred fold increase in the numbers
0:32:22 > 0:32:26of crown-of-thorns has devastated local reefs.
0:32:26 > 0:32:31It may have been caused by people over fishing its predators.
0:32:31 > 0:32:34They are very, very prolific.
0:32:34 > 0:32:37These guys are just wiping coral out.
0:32:39 > 0:32:41But killing crown-of-thorns is tough.
0:32:41 > 0:32:46Cut them in two and both halves can survive.
0:32:46 > 0:32:50The only ways to get rid of them - inject them with poison,
0:32:50 > 0:32:53or bag them up and take them away.
0:32:53 > 0:32:56We're going to actually remove these from the reef.
0:32:56 > 0:32:59These guys are just wiping coral out.
0:33:01 > 0:33:03Look at it reacting!
0:33:07 > 0:33:11We're finding more and more of them all over the seabed.
0:33:11 > 0:33:17And you can actually just see the way they're moving over the surface of the coral.
0:33:17 > 0:33:21Together with other factors like warming seas, this has
0:33:21 > 0:33:25contributed to the destruction of over 22% of the reefs
0:33:25 > 0:33:28in the south west Indian Ocean alone.
0:33:36 > 0:33:39But there is still hope.
0:33:39 > 0:33:43Tooni and Philippe head off to discover how damaged coral reefs
0:33:43 > 0:33:48could be revived using a new scientific technique.
0:33:48 > 0:33:53Leading the work here is Tanzanian scientist, Nsajigwa Mbije.
0:33:53 > 0:33:57- Hello, I'm Tooni.- Tooni, I'm Mbije.
0:33:57 > 0:33:59- Philippe.- Philippe.
0:33:59 > 0:34:01- Nice to meet you. - Thank you for coming.
0:34:01 > 0:34:04Hello, everybody. How are you?
0:34:04 > 0:34:10Mbije's working on a project around Chumbe, which is just,
0:34:10 > 0:34:13to me, a great example of really innovative science.
0:34:13 > 0:34:17It's the first time this methodology has been used in the Indian Ocean.
0:34:17 > 0:34:20They gear up to visit Mbije's laboratory,
0:34:20 > 0:34:25not on land, but about ten metres beneath the water's surface.
0:34:25 > 0:34:26Go, Mbije!
0:34:28 > 0:34:31Go, Philippe!
0:34:31 > 0:34:36It's a facility which could hold an answer to saving the coral reefs.
0:34:36 > 0:34:39A man-made coral garden.
0:34:48 > 0:34:49What we're looking at here,
0:34:49 > 0:34:54is almost the Indian Ocean equivalent of a garden centre.
0:34:54 > 0:35:01In this whole nursery, there are about 9,200 individual little pieces of coral.
0:35:02 > 0:35:08These little bits of coral or nubbins are taken from a mother colony
0:35:08 > 0:35:09from a different location
0:35:09 > 0:35:13and moved into this area, where they're basically grown.
0:35:13 > 0:35:17It's a little bit like pruning.
0:35:17 > 0:35:23The plan is to help save endangered reefs by transplanting living coral into them.
0:35:24 > 0:35:28But direct transplantation has had little success.
0:35:28 > 0:35:33Mbije and his team are growing young coral in this protected environment,
0:35:33 > 0:35:37till it's strong enough to survive being transplanted.
0:35:37 > 0:35:39The first thing Mbije does
0:35:39 > 0:35:43is collect young coral from a healthy reef.
0:35:43 > 0:35:46Then he cuts the coral nubbins off.
0:35:46 > 0:35:49Kind of like taking prunings from a tree
0:35:49 > 0:35:53and he puts them into these small little rubber tubes.
0:35:55 > 0:36:01Although it doesn't look like much, that little section of coral is actually alive.
0:36:01 > 0:36:07The coral will grow from what looks like something that potentially doesn't amount to much
0:36:07 > 0:36:11and that could spell the survival of the coral reef
0:36:11 > 0:36:15in some areas where they've been decimated in the Indian Ocean.
0:36:15 > 0:36:18The coral can't be left on its own.
0:36:18 > 0:36:21It needs constant care.
0:36:21 > 0:36:25So, Mbije's weeding the garden.
0:36:25 > 0:36:28This blanketing algae can smother the corals.
0:36:28 > 0:36:30So, by removing all of this,
0:36:30 > 0:36:35these corals have an opportunity to grow in as healthy a habitat as possible.
0:36:37 > 0:36:42Once the nubbins have spent about ten months here, they're ready for transplantation.
0:36:44 > 0:36:49If this technique is successful, it could help regenerate damaged reefs,
0:36:49 > 0:36:53not just in the Indian Ocean, but across the entire world.
0:37:00 > 0:37:05It's really encouraging to see that kind of methodology is actually being used in
0:37:05 > 0:37:11areas such as this, where there obviously isn't a huge amount of money to invest in marine science.
0:37:11 > 0:37:13But this technique is so simple
0:37:13 > 0:37:17and so cheap, basically, it just requires an awful lot of manpower.
0:37:17 > 0:37:21We've already lost at least 25% of the world's coral reefs,
0:37:21 > 0:37:24so now, because we're taking an active role in their destruction,
0:37:24 > 0:37:28this is an opportunity to take an active role in their restoration.
0:37:28 > 0:37:32And it's a very hopeful time right now.
0:37:37 > 0:37:39As the day ends...
0:37:39 > 0:37:42- I planted coral today.- Yay! - Fingers of greenness.
0:37:42 > 0:37:45It's a chance to plan the next stage of the expedition.
0:37:45 > 0:37:48Yeah, so up here... I've not been here before.
0:37:48 > 0:37:50This looks fantastic!
0:37:56 > 0:38:02People have been living on the shores of the Indian Ocean for over 100,000 years.
0:38:02 > 0:38:09How they've related to this vast body of water is the speciality of maritime archaeologist, Lucy Blue.
0:38:11 > 0:38:16I'm trying to work out how different people, different cultures
0:38:16 > 0:38:19would have approached this sea, this ocean.
0:38:19 > 0:38:24Obviously, there are certain parameters they were constrained by, so the winds and the currents...
0:38:24 > 0:38:27What were the challenges that they faced?
0:38:30 > 0:38:32Trade and migration in the Indian Ocean
0:38:32 > 0:38:36has been dominated by the powerful currents that flow
0:38:36 > 0:38:39uninterrupted for thousands of miles across it,
0:38:39 > 0:38:43before crashing into the East African coast.
0:38:43 > 0:38:48This gives you a really good idea of the way the currents are moving along this coastline.
0:38:48 > 0:38:54Particularly this East African coastal current or the Zanzibar one.
0:38:54 > 0:38:58The combination of the currents and the winds have dictated the way people manoeuvred
0:38:58 > 0:39:01around this - particularly this part of the Indian Ocean.
0:39:01 > 0:39:08Lucy believes there's much to learn from mankind's battles with these treacherous currents.
0:39:08 > 0:39:13So the expedition's heading for a site of particular interest to her.
0:39:13 > 0:39:20The wreck of a ship sunk 40 years ago in the unpredictable waters of the Indian Ocean.
0:39:20 > 0:39:27To avoid the same fate, the expedition ship will have to be extremely cautious.
0:39:27 > 0:39:33When I was talking to the skipper earlier, he was saying this is actually quite a treacherous area
0:39:33 > 0:39:39and we're not actually mooring up because the currents are quite complex and unpredictable.
0:39:40 > 0:39:45But when they reach the site, they find they aren't the only ones interested in it.
0:39:45 > 0:39:48A group of local salvagers are already here,
0:39:48 > 0:39:53trying to break up the ship and recover valuable metals.
0:39:53 > 0:39:56They're none too pleased to have competition.
0:39:56 > 0:39:59All right, folks, we got a bit of a situation out there.
0:39:59 > 0:40:04There's a bunch of guys who are trying to cut off the propeller with welding gear.
0:40:04 > 0:40:09I don't know whether they think we're going to try and poach their propeller from them,
0:40:09 > 0:40:13it's big and its worth a lot of money, but they're protecting themselves with spear guns
0:40:13 > 0:40:16and Scotty actually had one of them go to him...
0:40:19 > 0:40:24As expedition leader, Paul's worried about the safety his team.
0:40:24 > 0:40:29But for Lucy, this is an example of a worldwide problem she often faces.
0:40:29 > 0:40:33The destruction of archaeological sites.
0:40:33 > 0:40:37There's nothing we can do and if they start ripping off the portholes
0:40:37 > 0:40:40and all the rest of it, there's nothing for anybody to see.
0:40:40 > 0:40:44- There's nothing for anybody to learn about it.- I'm actually rooting for them.- Why?!
0:40:44 > 0:40:47- Well, I feel...- I think we could end up having some contretemps!
0:40:47 > 0:40:50I feel the ship is in their waters
0:40:50 > 0:40:54and that propeller and any other bits they can use will sustain
0:40:54 > 0:40:57their livelihood better than tourists coming to look at it.
0:40:57 > 0:41:01I'm not sure about that because you have that thing is there for an instance.
0:41:01 > 0:41:04They are going to reap an immediate reward.
0:41:04 > 0:41:07It's just condoning that whole activity and encouraging other people
0:41:07 > 0:41:10to do it on wrecks throughout the world and then it's gone.
0:41:10 > 0:41:12Whichever one of you is right
0:41:12 > 0:41:14it's not the immediate problem.
0:41:14 > 0:41:17The immediate problem is that they've got spear guns
0:41:17 > 0:41:20and they exhibited very threatening behaviour.
0:41:22 > 0:41:24The situation is tense.
0:41:24 > 0:41:28A crew member who speaks Swahili has gone over to explain
0:41:28 > 0:41:31that the team are just here to dive the wreck.
0:41:34 > 0:41:36Mike... Mike this is Richard. Come in, over.
0:41:36 > 0:41:40We've had a talk with the salvage crew
0:41:40 > 0:41:44and they've given us permission to dive on the site.
0:41:44 > 0:41:47Mike, that's fantastic.
0:41:47 > 0:41:51The salvagers stop diving and the team can get to work.
0:42:01 > 0:42:03This is what the salvagers are after,
0:42:03 > 0:42:06the remains of the Paraportiani.
0:42:06 > 0:42:10Wow, it's absolutely huge!
0:42:10 > 0:42:11After 40 years on the bottom,
0:42:11 > 0:42:15there's still a lot left of this 94 metre cargo ship.
0:42:18 > 0:42:21It's clear from the chains and pulleys that the salvagers are
0:42:21 > 0:42:25well on the way to removing the huge bronze propeller.
0:42:25 > 0:42:28Bronze scrap is worth thousands of pounds per tonne.
0:42:30 > 0:42:32It's going to be a lot of work to shift this.
0:42:32 > 0:42:35And ultimately it's setting a precedent for just ripping
0:42:35 > 0:42:40shipwrecks apart, regardless of whether they're 40 years old
0:42:40 > 0:42:43or 400 years old.
0:42:46 > 0:42:50All shipwrecks tell the story of a moment in time when a combination
0:42:50 > 0:42:55of circumstances came together to create a catastrophe.
0:42:55 > 0:42:59The Paraportiani sunk here in 1967,
0:42:59 > 0:43:04early in the evening, carrying wheat from Romania to Jeddah.
0:43:04 > 0:43:08The ship was meant to go via the Suez Canal,
0:43:08 > 0:43:13but with the Arab-Israeli war in full swing, that was closed
0:43:13 > 0:43:17forcing the Paraportiani to travel right round Africa.
0:43:17 > 0:43:20For weeks the voyage went well.
0:43:20 > 0:43:24Then with just days to go, things went badly wrong.
0:43:24 > 0:43:28We believe that they'd lost their radar and their echo sounder
0:43:28 > 0:43:33and they were basically travelling in very unfamiliar waters
0:43:33 > 0:43:38so they had to resort to compass and sextant and navigating by the stars
0:43:38 > 0:43:42in currents which they didn't understand.
0:43:42 > 0:43:46Just imagine the sense of terror
0:43:46 > 0:43:50coming up on this reef completely lost.
0:43:50 > 0:43:53The noise, the panic...
0:44:01 > 0:44:04She hit this reef behind us and then broke her back.
0:44:06 > 0:44:09Sprawling down here onto the sand.
0:44:12 > 0:44:15Somehow, everyone on board, survived,
0:44:15 > 0:44:21but the reef and the currents battered and sank the Paraportiani.
0:44:21 > 0:44:28Considering she's only been down 40 years there's an amazing amount of marine life down here.
0:44:30 > 0:44:35The Paraportiani may be home to many fish, but Lucy is shocked
0:44:35 > 0:44:39at how the salvagers are wiping out precious historical information.
0:44:43 > 0:44:46I mean, they've got rigs up there, they've got the whole works.
0:44:46 > 0:44:48Is it pretty much free game?
0:44:48 > 0:44:53It's free game, this is not in the marine reserve area so there's
0:44:53 > 0:44:57nothing in terms of the conservation of this particular zone that says...
0:44:57 > 0:45:00and anyway, I'd imagine it's very difficult to police.
0:45:00 > 0:45:02I know how difficult it is in the UK!
0:45:08 > 0:45:12My job, on a daily basis, is trying to battle against the problems
0:45:12 > 0:45:14with treasure hunters and salvage work.
0:45:14 > 0:45:16When you do meet it face-to-face,
0:45:16 > 0:45:22you can't but despise it and everything it represents.
0:45:28 > 0:45:32Ten days ago, the expedition launched the Argo float
0:45:32 > 0:45:36to monitor the depths of the Indian Ocean.
0:45:36 > 0:45:41There it goes! I'm waving goodbye to it. It's a four-year mission.
0:45:41 > 0:45:47It's now scheduled to surface and upload its first data,
0:45:47 > 0:45:50but has its mission succeeded?
0:45:50 > 0:45:52- So this is...- The moment of truth.
0:45:52 > 0:45:56Well it is the moment of truth because with any luck,
0:45:56 > 0:46:01if we can get this through we're going to figure out if the Argo
0:46:01 > 0:46:04actually worked. So hang on.
0:46:04 > 0:46:08- Is that the map?- That's it.
0:46:08 > 0:46:11- That's it! It's a transmit.- It is!
0:46:11 > 0:46:12So it's working?
0:46:14 > 0:46:17The map tracks the float's position from where Paul
0:46:17 > 0:46:22powered it up, to when it surfaced and successfully uploaded its data.
0:46:22 > 0:46:25This must be us going out.
0:46:25 > 0:46:29This is when we deployed it and it sank.
0:46:29 > 0:46:31And this is it here. It didn't get stuck.
0:46:31 > 0:46:36It's going on the expected track which is north and then north west.
0:46:36 > 0:46:39It's come up and it's sent the right expected data up.
0:46:39 > 0:46:43So do you feel a flutter of pride that it actually worked?
0:46:47 > 0:46:49The big thing for me, and it does excite me,
0:46:49 > 0:46:53is that it's real-time data so they're all coming up and down
0:46:53 > 0:46:56all sending up temperature, salinity, depth and where they are.
0:46:56 > 0:47:00For me, it's the fact that there are 3,000 plus
0:47:00 > 0:47:02of the Argo floats all over the world.
0:47:02 > 0:47:05So our little float is basically
0:47:05 > 0:47:09representative of this huge, global data set.
0:47:11 > 0:47:15Scientists are already using the data to look into the future and
0:47:15 > 0:47:20determine how our oceans and climate might change over the next decade.
0:47:26 > 0:47:30With just two days left, the team wants to see how one of the oceans
0:47:30 > 0:47:34most elusive residents is faring in these fast changing waters.
0:47:39 > 0:47:43The hunt brings them here to the Bazaruto Archipelago,
0:47:43 > 0:47:47a chain of islands 20 miles off the coast of Mozambique.
0:47:53 > 0:47:56The islands are hammered by the powerful waves and winds that have
0:47:56 > 0:48:02shaped these 100-metre high dunes, built up over thousands of years.
0:48:04 > 0:48:10You really get a sense of the power of the wind and the ocean here.
0:48:12 > 0:48:16Just looking out over the Indian Ocean. Next stop, Australia.
0:48:16 > 0:48:19All of that power of the Indian Ocean just slams into this coast
0:48:19 > 0:48:22and it kind of stings the back of your legs
0:48:22 > 0:48:24like you're getting sandblasted.
0:48:24 > 0:48:26Slamming into us at the moment!
0:48:30 > 0:48:34The Bazaruto Archipelago acts as a barrier, absorbing the fury
0:48:34 > 0:48:38of the Indian Ocean and protecting the 20-mile stretch
0:48:38 > 0:48:40of water on the other side.
0:48:43 > 0:48:47Tooni believes its here that the team may find a sensitive barometer
0:48:47 > 0:48:51of the health of the Indian Ocean, one of its rarest animals.
0:48:53 > 0:48:58So this is the dugong, with the best Latin name ever. The Dugong dugong.
0:49:00 > 0:49:05A really bizarre hybridisation between the dolphin tail
0:49:05 > 0:49:11and then you've got a cow-like/ elephantine front end.
0:49:11 > 0:49:15They grow up to about 3.4 metres so they're a fairly decent size.
0:49:17 > 0:49:23Dugongs once thrived in this part of the Indian Ocean, but not any more.
0:49:23 > 0:49:26Hunting and entrapment in fishermen's nets
0:49:26 > 0:49:29have drastically reduced their numbers.
0:49:29 > 0:49:33So how well is this tiny population doing?
0:49:37 > 0:49:42Right here is pretty much the last viable population of dugong in the western Indian Ocean.
0:49:42 > 0:49:46So we've come to this specific area to see if we can find them and,
0:49:46 > 0:49:50to be honest, it would be an absolute joy and something really special if we did.
0:49:50 > 0:49:54But finding them, I think, is going to be a bit of a nightmare.
0:49:54 > 0:49:59Dugongs have always been mysterious.
0:49:59 > 0:50:04Their unusual body shape probably inspired the myth of the mermaid.
0:50:04 > 0:50:08They have what's called a fusiform body, combining the fluked tail
0:50:08 > 0:50:12of a fish with forelimbs and a snout-like head.
0:50:15 > 0:50:18This isn't the first time Tooni's searched for them.
0:50:18 > 0:50:24She knows how tough it is looking for a few dugongs in a very big ocean.
0:50:24 > 0:50:29I spent a month hunting for dugong and I didn't see a single flipping
0:50:29 > 0:50:35whisker so if we do see them we are going to be exceptionally lucky.
0:50:35 > 0:50:36Ready then, team?
0:50:39 > 0:50:43If they can find them it would be a rare chance for Tooni
0:50:43 > 0:50:45to see how well they're coping.
0:50:47 > 0:50:52They head for an area they've been told has a high density of dugongs,
0:50:52 > 0:50:56but Tooni is not convinced.
0:50:56 > 0:50:59High density is a bit of misnomer. It's a slightly misleading name.
0:50:59 > 0:51:04High density suggests that there's loads of them swimming around but in actual fact that's not true.
0:51:04 > 0:51:09It just means that more of them have been spotted in that location than anywhere else.
0:51:12 > 0:51:17Tooni still hopes to find a few, but dugongs are notoriously timid.
0:51:19 > 0:51:21The plan is to just cut the engines.
0:51:21 > 0:51:27It's gonna have to be really, really quiet and a slow operation so we don't freak them out,
0:51:27 > 0:51:32cos as soon as they hear the boat noise or hear splashing they're just going to be gone.
0:51:35 > 0:51:38If we smell a dugong. it's going to be miraculous.
0:51:41 > 0:51:44One of the crew believes they've seen a dugong.
0:51:48 > 0:51:52So Tooni takes a chance and jumps in, to try and get close.
0:51:59 > 0:52:03But underwater the visibility is terrible.
0:52:05 > 0:52:08Finding the dugongs will take more than this.
0:52:10 > 0:52:13It just shows how bad the visibility is cos we didn't see diddly.
0:52:16 > 0:52:20Paul is going to try and spot them from the air and guide Tooni to them.
0:52:24 > 0:52:26These things are really hard to find,
0:52:26 > 0:52:29so this is our secret weapon and Tooni's really counting on me
0:52:29 > 0:52:34up there. She's counting on me to be able to see them from about 500ft and I can steer her in.
0:52:54 > 0:52:55There's a bunch of goats ahead of us.
0:52:55 > 0:52:57So what we've got to try and do is
0:52:57 > 0:53:01get airborne before we hit any of the goats.
0:53:21 > 0:53:26Tooni, Tooni, it's Paul in Victor Charlie here. Copy.
0:53:26 > 0:53:28Paul, this is Tooni, over.
0:53:28 > 0:53:32We can see you. If you just follow us now, follow this bearing.
0:53:32 > 0:53:34Great. Keep us posted. Out.
0:53:52 > 0:53:56- Suddenly, Paul sees a grey smudge in the water.- There's a dugong!
0:53:56 > 0:54:00Dugong dugong. Right there!
0:54:00 > 0:54:03Just coming around, the wing's in the way but you'll see him in a bit.
0:54:06 > 0:54:09We've got a dugong. In fact, there's a small group.
0:54:11 > 0:54:16Tooni, Tooni, we are over a group of dugongs.
0:54:16 > 0:54:18Get your foot down cos we're over them right now.
0:54:18 > 0:54:22That's great news, Paul, great news. We'll make our way towards you now.
0:54:25 > 0:54:29We head straight for the aeroplane. Straight for the aeroplane.
0:54:33 > 0:54:35I can sense dugong.
0:54:35 > 0:54:37I can sense them.
0:54:42 > 0:54:45Paul, Paul, which direction are they travelling in? Over.
0:54:45 > 0:54:48They're right ahead, right ahead.
0:54:52 > 0:54:55They're kind of 2 o'clock running parallel with you.
0:54:57 > 0:55:00They're at the surface, they're at the surface.
0:55:00 > 0:55:02Oh! I can see them!
0:55:02 > 0:55:06Tooni, can you see them? They're right in front of you, over.
0:55:06 > 0:55:09Roger that. I can see them, Paul. I can see them.
0:55:25 > 0:55:31I'm so happy that we've seen them cos I didn't think we were going to at all, if truth be told.
0:55:37 > 0:55:40Seeing the group of dugongs
0:55:40 > 0:55:44is positive evidence that the population here is surviving.
0:55:47 > 0:55:51But then Paul spots something even more encouraging.
0:55:51 > 0:55:55A sign that the dugongs here may be in better shape than they had thought.
0:55:56 > 0:56:00And a calf, you see the calf as well? Right there, right there.
0:56:01 > 0:56:04Fantastic news! Look at them.
0:56:04 > 0:56:06Whoo! Three and a half dugong.
0:56:09 > 0:56:14The dugongs are doing more than surviving, they're reproducing.
0:56:14 > 0:56:16It's incredibly good news.
0:56:16 > 0:56:18How's that, that's all right, isn't it?
0:56:28 > 0:56:32The team's success has come just in time.
0:56:32 > 0:56:34We're off, we're getting so low on fuel, over.
0:56:34 > 0:56:40OK, Paul, thank you so much, we did see the dugong which is absolutely fantastic.
0:56:51 > 0:56:52Here we go!
0:56:52 > 0:56:55It's the end of their Indian Ocean Odyssey.
0:56:55 > 0:56:58It was excellent.
0:56:58 > 0:57:00They've journeyed through seas
0:57:00 > 0:57:04that supports some of the most varied marine life on the planet.
0:57:04 > 0:57:08Diving with the manta rays is one of the finest dives I've ever had.
0:57:08 > 0:57:11You know, I've done over 6,000 of them.
0:57:15 > 0:57:18The most special part of this expedition, for me,
0:57:18 > 0:57:21has been getting a chance to see this part of the world.
0:57:21 > 0:57:25The diversity that's here, the diversity of life and abundance of life.
0:57:25 > 0:57:28From an ocean perspective, because coral reefs
0:57:28 > 0:57:32here in the Indian Ocean are some of the most bio diverse in the world.
0:57:33 > 0:57:38Coming on this project and seeing, you know, looking at the marine life
0:57:38 > 0:57:40as well as the cultural context
0:57:40 > 0:57:44has just reinforced to me how little we know about this ocean.
0:57:44 > 0:57:47The Indian Ocean is so rich.
0:57:47 > 0:57:49I'm worried about it, though.
0:57:50 > 0:57:53So far, the Indian ocean is holding it's own
0:57:53 > 0:57:56but in a world that's being transformed so rapidly,
0:57:56 > 0:57:59how much longer can it cope?
0:58:02 > 0:58:06Next time the team continues to explore the the Indian Ocean.
0:58:08 > 0:58:10They'll investigate how marine creatures can help
0:58:10 > 0:58:12predict extreme weather.
0:58:12 > 0:58:15They'll dive the remains of a medieval village...
0:58:15 > 0:58:18See this design here, that's got to be oriental.
0:58:18 > 0:58:22And try to protect the largest fish in the sea.
0:58:32 > 0:58:34Subtitles by Red Bee Media Ltd
0:58:34 > 0:58:36E-mail subtitling@bbc.co.uk