AHMED_SHAMOON DR_ENRICO_GENNARI FARISH_MOHAMED MORNE_HARDENBERG NARRATOR_STEVE_BACKSHALL STEVE_BACKSHALL NARRATOR STEVE BACKSHALL Sharks are the most feared predators on Earth. NARRATOR STEVE BACKSHALL But, also the most misunderstood. NARRATOR STEVE BACKSHALL I've been diving with sharks for over 30 years, now I'm getting closer than ever before. NARRATOR STEVE BACKSHALL Journeying deep into our oceans to explore their hidden lives. NARRATOR STEVE BACKSHALL Challenging what we think we know. To better understand some of the most mysterious creatures that exist in our world. NARRATOR STEVE BACKSHALL Across the world, sharks come in surprisingly different shapes and sizes. NARRATOR STEVE BACKSHALL But every one of them is a perfect predator. NARRATOR STEVE BACKSHALL One of the best places to witness these extreme hunters in action... is the rich and dynamic habitats of the Indian Ocean. NARRATOR STEVE BACKSHALL The Indian Ocean is home to a vast tropical paradise. Fringed by coral reefs, teeming with life. NARRATOR STEVE BACKSHALL An amazing array of predatory sharks live here, and all have found clever ways to take advantage of the abundant food. NARRATOR STEVE BACKSHALL But now, surrounded by two and a half billion people, this ocean is changing, fast. STEVE BACKSHALL Sharks are the masters of adaptation. For more than 400 million years they've been evolving to conquer all of their challenges. But now, with the threats of climate change and pollution and over-fishing, the question is, is change happening too quickly? And can the sharks keep up? NARRATOR STEVE BACKSHALL I'm on a journey to reveal what makes sharks perfect predators. And find out if they'll be able to survive our rapidly changing world. NARRATOR STEVE BACKSHALL I'm starting my journey south of Durban off the east coast of South Africa. NARRATOR STEVE BACKSHALL Just a few kilometres offshore, there's a species that demonstrates why sharks are at the pinnacle of predation. STEVE BACKSHALL These are Black Tip Sharks. A really classic shark design. STEVE BACKSHALL It is a long-distance migrant, one that will cover thousands of miles. NARRATOR STEVE BACKSHALL These sharks are formidable hunters. The secret to their success is a raft of super-senses, all honed to locating and targeting food. NARRATOR STEVE BACKSHALL They use sight, sound and a supremely powerful sense of smell. But sharks have some unusual senses too. NARRATOR STEVE BACKSHALL Organs in their snouts detect tiny electrical fields produced by the twitching of muscles in fish. And, along their flanks, are sensitive cells that detect movements in the water. STEVE BACKSHALL It's remarkable that you can swim in seas like these where the visibility is so low, and yet they come within touching distance of you, and never show any urge to bite. They know exactly what's food and they stay well away from us. NARRATOR STEVE BACKSHALL But it's not just their bodies that make sharks such effective predators. It's their brains too. Sharks are strategic, using their skills creatively to capture prey in a range of different scenarios. One of the most dramatic displays of this takes place in these same South African waters. NARRATOR STEVE BACKSHALL It's June, and offshore, fish are gathering. NARRATOR STEVE BACKSHALL Seasonal temperature changes in the water trigger hundreds of millions of sardines to swim north along the coastline. NARRATOR STEVE BACKSHALL This is the sardine run. NARRATOR STEVE BACKSHALL Their swirling congregations can measure 30 meters deep and one-and-a-half kilometres wide. NARRATOR STEVE BACKSHALL It's one of the largest migrations of prey animals in our oceans. NARRATOR STEVE BACKSHALL And, where there's prey... there are predators. NARRATOR STEVE BACKSHALL Spinner Sharks have followed their highly tuned senses to find the sardines. Now, they must catch them. NARRATOR STEVE BACKSHALL The sardines have an effective defence, there's safety in numbers. NARRATOR STEVE BACKSHALL In the mesmerising mass, it's difficult for a shark to lock onto a single target. NARRATOR STEVE BACKSHALL But an opportunity is about to arrive. NARRATOR STEVE BACKSHALL A natural banquet like this is rare and attracts a lot of attention. NARRATOR STEVE BACKSHALL Pelted by gannets and charged by dolphins, the sardines are herded into tightly packed clusters known as bait balls. The Spinners seize their opportunity, snatching easy mouthfuls of the densely corralled fish. NARRATOR STEVE BACKSHALL The food they get here could provide a calorific windfall. NARRATOR STEVE BACKSHALL But they need to be quick. NARRATOR STEVE BACKSHALL At 13 meters, a Bryde's Whale is capable of swallowing hundreds of sardines in a single mouthful. NARRATOR STEVE BACKSHALL A combination of physical attributes and smart behaviour has allowed Spinner Sharks to capitalise on this immense feeding opportunity. NARRATOR STEVE BACKSHALL But things are changing. NARRATOR STEVE BACKSHALL A warming of the Indian Ocean is affecting the cold-water currents that trigger the sardine run. The migration has failed to happen three times in the last 20 years. NARRATOR STEVE BACKSHALL Without a reliable sardine run, Spinner Sharks, and other species, will go hungry. NARRATOR STEVE BACKSHALL All across this ocean, human driven change is putting pressure on sharks. I want to know if an adaptable strategy could be a key to their survival. NARRATOR STEVE BACKSHALL While many sharks struggle with human influence, there's one species that may have learned to benefit from it. NARRATOR STEVE BACKSHALL To find out how, I'm travelling over 5,000 kilometres from South Africa to the island chain of the Maldives. NARRATOR STEVE BACKSHALL In Fuvahmulah, local fishermen are bringing in a day's catch of tuna. NARRATOR STEVE BACKSHALL Watching and waiting, are tiger sharks. STEVE BACKSHALL So, for generations now, the fishermen coming back into the harbour have been cleaning their catch right here, so it's likely there will be a lot of big sharks around, they're gonna be excited, they're gonna be food focused. It's critical that we are always on our game watching each other's backs, and just have the ultimate respect for these animals. NARRATOR STEVE BACKSHALL Tiger sharks are big. And, if you're getting in the water, you need to be on your guard. NARRATOR STEVE BACKSHALL But they're difficult to spot until they're close by. NARRATOR STEVE BACKSHALL The tiger-like stripes that give them their name break up their bulk, helping to keep them hidden. STEVE BACKSHALL Diving with Tiger Sharks you have to be super cautious, because you never quite know what they're gonna do next. NARRATOR STEVE BACKSHALL They have a predatory strategy that is extremely flexible. STEVE BACKSHALL Tiger Sharks have a reputation for being the dustbins of the deep, but that's a little unjustified. Actually, they are just opportunists, able to take advantage of any food source that comes their way. NARRATOR STEVE BACKSHALL They eat everything, from live fish, crustaceans and sea turtles to dead animals. This female has found a meal in the discarded fish guts. NARRATOR STEVE BACKSHALL But now I'm up close, I realise there's more to this story. STEVE BACKSHALL Most of the big animals you can see here are females, when you look at their bellies you can see that it's full and round. These are expectant mothers. NARRATOR STEVE BACKSHALL The fishing waste eaten in these waters provides vital nourishment for the 30 pups she is likely carrying. NARRATOR STEVE BACKSHALL And this environment could make a perfect nursery for the next generation of Tigers. STEVE BACKSHALL I can understand how, for many people, this is the ultimate sign of terror. For me, the Tiger is a symbol of the majesty of our ocean's top predators. What an animal. NARRATOR STEVE BACKSHALL What I've seen in the Maldives gives me hope, at least some species of shark are finding ways to co-exist with humans. NARRATOR STEVE BACKSHALL Tigers are able to do this because they're generalists, eating a wide range of food. NARRATOR STEVE BACKSHALL But what does the future hold for the many sharks that are highly specialised hunters. NARRATOR STEVE BACKSHALL Travelling over 6,000 kilometres, the Indian Ocean meets the Pacific on the northern shores of Australia. NARRATOR STEVE BACKSHALL This is the home of the Tasselled Wobbegong. NARRATOR STEVE BACKSHALL Unlike its ocean-wandering cousins, this shark likes to stay local. NARRATOR STEVE BACKSHALL Its bizarre looks are part of a predatory strategy that has to be seen to be believed. NARRATOR STEVE BACKSHALL The Wobbegong seeks out the perfect spot and settles in. NARRATOR STEVE BACKSHALL A master of disguise, he's so adapted to his environment that he's come to resemble it. NARRATOR STEVE BACKSHALL Using his tail like a lure, he waves it back and forth. Mimicking a moving fish. NARRATOR STEVE BACKSHALL Real fish move in, thinking it's safe. NARRATOR STEVE BACKSHALL The Wobbegong is waiting...for the precise moment. NARRATOR STEVE BACKSHALL These sharks are ambush hunters. NARRATOR STEVE BACKSHALL By conserving energy, they need only eat every three days. NARRATOR STEVE BACKSHALL The sudden opening of their mouths sucks water, and prey, into their jaws. NARRATOR STEVE BACKSHALL The wobbegong's predatory strategy can only work if coral reefs stay healthy. NARRATOR STEVE BACKSHALL Being specialists makes them particularly vulnerable to change. And they're not the only ones. NARRATOR STEVE BACKSHALL So far on my journey I've only dived in the daylight. But to really appreciate the secret lives of sharks, I need to see them at their most dynamic. In the Maldives, in the heart of the Indian Ocean, that means diving at night. STEVE BACKSHALL We jumped into the water at dusk, just as the sun's setting. This tends to be one of the most active times for lots and lots of shark species. NARRATOR STEVE BACKSHALL These are Tawny Nurse Sharks. They're nocturnal, reef hunting specialists. STEVE BACKSHALL When feeding begins it turns into a frenetic display, with fins and tails thrashing everywhere. STEVE BACKSHALL They scour the reef for snails and squid. STEVE BACKSHALL They're tangled all over each other as they nuzzle down into every crack and crevice looking for a feed. NARRATOR STEVE BACKSHALL When they find something, they suck it up like a vacuum cleaner. STEVE BACKSHALL Oh, hello. Didn't see you there. I seem to have found myself on top of a Nurse Shark. Just crept right underneath me. [LAUGHS]. NARRATOR STEVE BACKSHALL They're so effective as reef predators they can find everything they need within their small home range. STEVE BACKSHALL You can see how much the lives of the nurse shark are intricately interwoven with that of healthy coral. It's a home, a habitat, yes, but it's so much more than that. NARRATOR STEVE BACKSHALL Tawny Nurse Sharks are widely distributed across the ocean. But, just like the Tasselled Wobbegong, they are specialists that rely on reefs, and could be vulnerable if this habitat changes. NARRATOR STEVE BACKSHALL As much as 25% of all marine life lives on corals. Sharks provide a regulating service over the entire oceanic food chain. Keeping populations of fish and reef dwellers in check. STEVE BACKSHALL So, just as important as these reefs are to the health of sharks, sharks are to the health of these reefs. NARRATOR STEVE BACKSHALL But it's a fragile harmony, highly vulnerable to outside influence. NARRATOR STEVE BACKSHALL Many of the corals in this ocean are already in peril. STEVE BACKSHALL This is like gliding over the equivalent of a ghost town underwater. STEVE BACKSHALL The vibrant colours and abundant life is all gone, and that's down to warming of these tropical seas. STEVE BACKSHALL This is called coral bleaching. NARRATOR STEVE BACKSHALL Even a small increase in the water temperature can make coral sick, and cause them to die off, taking their abundance of food with them. STEVE BACKSHALL That will have knock on effects for everything that lives here, including the sharks. NARRATOR STEVE BACKSHALL The Indian Ocean is the warmest of all the world's oceans, and, due to climate change, its temperature is now rising the fastest. NARRATOR STEVE BACKSHALL Surrounded by more than two billion people, the pressure on these waters increases every day. NARRATOR STEVE BACKSHALL But the warming sea isn't the only issue here. NARRATOR STEVE BACKSHALL I'm searching for a shark whose feeding strategy puts it at risk, and it couldn't be more different than a predatory reef shark. STEVE BACKSHALL This gentle giant is a Whale Shark. The largest species of fish on our planet. And they get to that size despite the fact that they feed on very, very tiny organisms, plankton. NARRATOR STEVE BACKSHALL The lights from our boat have attracted plankton up from the depths, it's a rich soup of microscopic plants and animals, and this female is making the most of it. NARRATOR STEVE BACKSHALL She's a filter feeder, drawing in up to 6,000 litres of water an hour. Her gills do the important work of sieving out food in vast quantities. NARRATOR STEVE BACKSHALL She's focused on reaching a dense layer of plankton at the surface. NARRATOR STEVE BACKSHALL This gives me an opportunity to get closer to a Whale Shark than ever before. NARRATOR STEVE BACKSHALL But this encounter is tinged with sadness. NARRATOR STEVE BACKSHALL These waters contain a hidden poison: plastic. NARRATOR STEVE BACKSHALL Every day, eight million pieces of plastic find their way into our seas, by 2050 it's estimated that by weight there will be more plastic in our oceans than fish. As it breaks down into tiny pieces, these microplastics are consumed by filter feeders like Whale Sharks. It accumulates in their bodies and could make them ill. STEVE BACKSHALL A Whale Shark can live to be over 100 years of age, which means that the plastics that we drop into our ocean now could still be turning up in these animals in a century's time. NARRATOR STEVE BACKSHALL To appreciate the scale of the problem, I'm travelling to an area of the Maldives and into an ecological nightmare. STEVE BACKSHALL This is Tilapushi, so-called "Trash Island." It started in the early 90’s. Now around 500 tons of garbage is dumped here every single day. NARRATOR STEVE BACKSHALL Much of this is thought to be single use plastics. STEVE BACKSHALL One of the problems with this giant landfill is that a lot of this is just sloughing straight off into the oceans, or sloughing into the environment that we know is one of the most precious and important on the planet for sharks. NARRATOR STEVE BACKSHALL This is one dive I doubt I'll enjoy. STEVE BACKSHALL In these Indian Ocean waters there's plenty of life. But here is a depressing tangle of junk that they're living in. Endless remnants of local fishing, rudimentary floats from plastic bottles. Wow. NARRATOR STEVE BACKSHALL But there is hope here. The Maldives has recently banned the importation of many single use plastic items, and that's not all, they created a shark sanctuary which covers more than 900,000 square kilometres of ocean. Now I want to see the benefits first-hand. NARRATOR STEVE BACKSHALL I've come to the west of the Maldives, in search of a distance cousin of the sharks. NARRATOR STEVE BACKSHALL Reef Mantas. STEVE BACKSHALL For now, all I can see is blue, but that's quite positive. This green goo in the water is plankton, and that's exactly what will be attracting the mantas in. STEVE BACKSHALL Whoa! That is mind blowing! NARRATOR STEVE BACKSHALL This sanctuary is clearly working. This is the largest population of resident Reef Mantas on Earth, over 5,000 of them. It shows that species will flourish given the opportunity. STEVE BACKSHALL Six. We have six of them now. Even seeing one manta is about a special experience as you'll ever have underwater. Utterly exquisite. STEVE BACKSHALL The Manta Rays and Sharks are in the same animal group, and they share a common ancestor. The body plan though, in the Manta Rays, has expanded and extended, with the pectoral fins becoming wings. It drives them through the water in the most elegant, balletic, graceful form of locomotion found on our planet. NARRATOR STEVE BACKSHALL They too are filter feeders. They use Cephalic lobes to funnel water towards their mouths and filter out microscopic zooplankton. NARRATOR STEVE BACKSHALL As this ocean warms, the availability of plankton becomes more limited. But there is a glimmer of hope, mantas are well equipped for survival. STEVE BACKSHALL For its size, the manta has the largest brain of any fish. They're inquisitive, they're sensitive and they are, without question, intelligent. NARRATOR STEVE BACKSHALL Some scientists believe mantas are capable of making mental maps, using smells and visual cues they can navigate hundreds of kilometres to the most productive feeding grounds. So, for now at least, they can track down plankton wherever it's on offer. NARRATOR STEVE BACKSHALL The scale of human impact on this ocean is a huge challenge for mantas and sharks. I've seen how wildly different the hunting strategies of sharks can be, now I want to find out how adaptable those strategies are. NARRATOR STEVE BACKSHALL Due southwest from the Maldives, on the very edge of the Indian Ocean, is South Africa's Western Cape. I've come here to find out just how adaptable the most famous shark of all is. The Great White. NARRATOR STEVE BACKSHALL These sharks have a fearsome reputation that is based far more on fiction than fact. They're the ultimate predator, and possess the same supreme senses of smell, sight and electro reception that's found in most predatory sharks. NARRATOR STEVE BACKSHALL Their torpedo shape allows them to power at almost 25 kilometres per hour. With 300 razor sharp and self-replacing teeth, they can pierce all prey on contact. In all, it's a breathtakingly perfect hunter, capable of taking down any prey from fish, including other sharks, to dolphins and seals. NARRATOR STEVE BACKSHALL Yet still, white shark numbers have plummeted in some areas. My friend, and camera operator, MORNE HARDENBERG, knows these sharks well. MORNE HARDENBERG I grew up diving around these waters, I have a passion for the animals in the ocean, and being able to work with them the way that I do is really nothing but spectacular. NARRATOR STEVE BACKSHALL Morne has become increasingly worried about white sharks. MORNE HARDENBERG This used to be the best place in the world to see white sharks naturally hunt the Cape for seals. We've been finding it harder and harder to find sharks on this side of the coast. It's been quite a big change over the last four years. NARRATOR STEVE BACKSHALL It's the same story along most of the Western Cape. NARRATOR STEVE BACKSHALL There are various competing theories as to why white sharks are disappearing. I've come to Mossel Bay on the Western Cape, it's one of the few places where they're still seen. NARRATOR STEVE BACKSHALL I'm joining DR ENRICO GENNARI, who's studied white sharks for over a decade. He's tagged them to track their movements. And he may have some answers. STEVE BACKSHALL So, what do you think is the difference? Why is here remaining attractive and the other areas, the sharks are just staying away? DR ENRICO GENNARI Mossel Bay has got a lot to offer, fish, smaller sharks, they find them in quite good quantity around this coastline. NARRATOR STEVE BACKSHALL Up to 60% of the white shark's diet is made up of bottom dwelling fish, especially small shark species called Smooth Hounds and Soup Fins. In white shark hot spots, intense long line fishing is jeopardising this food supply. DR ENRICO GENNARI The white shark has started to move east, leaving the areas where there's not a lot of food left. If you go on an holiday and a local supermarket doesn't have the food, what do you do? You go to the next spot. That's what the white sharks are doing. NARRATOR STEVE BACKSHALL Here in Mossel Bay, large scale commercial fishing is banned, so numbers of prey fish are much healthier. This could be one of the reasons why white sharks are moving in. DR ENRICO GENNARI So, in a way, the harbour is providing almost a sanctuary for the smaller sharks in the area, and, by consequence, to the white sharks. NARRATOR STEVE BACKSHALL Mossel Bay has an ample supply of smaller sharks for white sharks to feed on, and there's another prey species in abundance here. NARRATOR STEVE BACKSHALL Seals. NARRATOR STEVE BACKSHALL To catch them, white sharks deploy an awe-inspiring hunting strategy. NARRATOR STEVE BACKSHALL Breaching. NARRATOR STEVE BACKSHALL For only a few hours at dawn and dusk, when the light is just right, they use their acute eyesight to pick out silhouetted seals on the surface. Without being spotted themselves. NARRATOR STEVE BACKSHALL It's the ultimate predatory move. Seals are found up and down South Africa's coastline, but Enrico wants to show me how seal predation here is different to everywhere else. NARRATOR STEVE BACKSHALL Witnessing this isn't straightforward. STEVE BACKSHALL A breach attack is so quick, so forceful, so effective, that it's almost impossible to pinpoint exactly when it's going to happen, but we can increase our chances of being able to film it using one of these. This is a decoy, which is a representation of a seal, it's gonna act at the surface very similarly to how a real seal would. NARRATOR STEVE BACKSHALL The decoy is harmless to the shark, and they release it when they realise it's not food. To analyse this behaviour, we're filming with slow motion cameras. STEVE BACKSHALL From here on in, all of our eyes are gonna be focused on that fake seal, and just hoping something happens. NARRATOR STEVE BACKSHALL We wait for almost an hour, until the light levels are ideal. STEVE BACKSHALL Aah! Wow! Unbelievable! No way, absolutely spectacular, in a perfect silhouette against the haze hanging over the beach. The greatest ambush on our planet, and it just happened right behind our boat! STEVE BACKSHALL If that had been a real seal it would be all over. NARRATOR STEVE BACKSHALL To see this shark's hunting strategy in more detail we check the slow motion footage. DR ENRICO GENNARI It carries on up and up. STEVE BACKSHALL Oh, that genuinely is absolutely breath-taking. STEVE BACKSHALL So, at that sort of size, we're thinking about three meters, would you even consider that an adult at that size? DR ENRICO GENNARI No, definitely not. That is a sub-adult. STEVE BACKSHALL Well, for a beginner, that's a pretty perfect hunt, isn't it? DR ENRICO GENNARI Yeah, I think it's quite close to become a very successful hunter. NARRATOR STEVE BACKSHALL Soon the failing natural light signals the end of the day's normal hunting window. STEVE BACKSHALL The sun's dropped below the hills, we probably have mere minutes of light left and then we're gonna have to call it a day. NARRATOR STEVE BACKSHALL In any other location, the hunting action would now be over. But, Enrico knows, unlike anywhere else on Earth, something truly amazing happens here. STEVE BACKSHALL Whoa! STEVE BACKSHALL Just as I thought it was all over, and I could barely see the decoy, all of a sudden all of this man-made light has just come all over the shore, hasn't it? DR ENRICO GENNARI Yeah, this is really unique about Mossel Bay, why sharks have learned to modify their natural behaviour to make the most out of a new situation that we, as humans, have provided. NARRATOR STEVE BACKSHALL These juvenile sharks appear to be taking advantage of the artificial light from nearby homes and hotels, to hunt later into the night. By expanding their window of opportunity, they're securing extra precious calories to help them develop and grow. What I've seen here is truly remarkable. It seems not only have white sharks moved location in response to over-fishing, but they've also adapted their hunting strategy to actively take advantage of human presence. NARRATOR STEVE BACKSHALL The fact it maybe the young sharks doing this is even more exciting. NARRATOR STEVE BACKSHALL And gives me hope for future generations. STEVE BACKSHALL It has to remain, surely, the most impressive predatory strategy, not just of any shark, but of any predator on the planet. NARRATOR STEVE BACKSHALL The Indian Ocean has shown me many of the magnificent predatory sharks that live on the planet. NARRATOR STEVE BACKSHALL I've seen they're highly intelligent. NARRATOR STEVE BACKSHALL And resilient. NARRATOR STEVE BACKSHALL But, crucially, they're adaptable. Over millions of years, they've risen and become perfect predators. Now it's time to give them a fighting chance, to thrive into the future. NARRATOR STEVE BACKSHALL To film the Indian Ocean episode, our team travelled right across these warm tropical waters. STEVE BACKSHALL Wow guys, look up, look up, look up! NARRATOR STEVE BACKSHALL Our most challenging shoot was in the Maldives... filming the elusive close cousins of sharks; manta rays. STEVE BACKSHALL That is mind blowing! NARRATOR STEVE BACKSHALL These protective waters are a sanctuary to the largest population in the world, but finding them in this changing ocean, can prove much more difficult than we ever imagined. It took a crew, assembled from across the globe, and an experienced local dive team. NARRATOR STEVE BACKSHALL The Maldives is a paradise destination for tourists, and a marine life hot spot. Manta rays here migrate seasonally, following their food: microscopic plankton. This is carried by strong currents, that flow east to west and back again... but climate change means the monsoon winds that produce these currents are becoming erratic. The whereabouts of the mantas' food is becoming unpredictable, and filming the mantas themselves is getting harder. NARRATOR STEVE BACKSHALL Leading our search is dive supervisor, AHMED SHAMOON. He's been diving with mantas for 25 years. AHMED SHAMOON Mantas are beautiful creatures for sure. For me, seeing an individual, which I know from before, is like meeting a friend again. NARRATOR STEVE BACKSHALL Shamoon advises us to head to the western side of the atolls, towards specific manta gathering sites, known as cleaning stations. These could offer good encounters. Shamoon's second in command, FARISH MOHAMED, heads in to scout for them. AHMED SHAMOON At the moment, nothing, but there's more than one station around the area, so they're gonna check the next one. NARRATOR STEVE BACKSHALL We know of multiple cleaning stations. We scout, scout, and then scout some more. FARISH MOHAMED No mantas in the cleaning station, we are very unlucky. NARRATOR STEVE BACKSHALL As our filming days slip away, we're beginning to run out of time. STEVE BACKSHALL So, we've been out here now for about a week, and so far, our search for mantas has not had any luck. NARRATOR STEVE BACKSHALL We travel to the other side of the atolls, but we're hit by some unseasonal and extreme conditions. STEVE BACKSHALL This is not ideal, and this is the Indian Ocean, it's supposed to be paradise! NARRATOR STEVE BACKSHALL But a nearby boat captain has reported seeing mantas on a cleaning station here. Even though the sea state is deteriorating, this could be our only chance. AHMED SHAMOON Let's hope for the best and the guys underwater, it's all up to you now. [LAUGHS]. STEVE BACKSHALL Comms check, comms check. Whoa! That is quite a current! The flow through here is absolutely extraordinary. If I let go, I'd be gone! NARRATOR STEVE BACKSHALL At last, we get eyes on a manta. STEVE BACKSHALL Oh, look up! Isn't that something! Absolutely exquisite! NARRATOR STEVE BACKSHALL It's food that attracts mantas to the general area, but this site offers something different. STEVE BACKSHALL Clustered around this rocky out crop are hundreds of small fish that specialise in cleaning larger animals, like manta rays. They'll pluck dead skin and parasites off their bodies, even help them to heal their wounds. NARRATOR STEVE BACKSHALL While we film our sequence underwater... the conditions for the topside team become very challenging. NARRATOR STEVE BACKSHALL As we surface, exiting the water now becomes the most dangerous part of our dive. NARRATOR STEVE BACKSHALL We've captured footage of mantas on cleaning stations, but what we set out to film was their incredible feeding behaviour. NARRATOR STEVE BACKSHALL The storm subsides, and we head to a protected lagoon. The light from our boat attracts plankton, which in turn, attracts mantas. STEVE BACKSHALL Wow. It kind of feels like I've just beamed into an episode of Stranger Things. STEVE BACKSHALL Oh, that's extraordinary! In situations like this where you have a glut of food, the mantas will spin round and round and round in a barrel roll, called cyclone feeding. It's simply exquisite. NARRATOR STEVE BACKSHALL These protected waters have enabled the growth of this population. It's the largest in the world, and they're resident all year round. But life beyond this safe haven is dangerous. STEVE BACKSHALL Just to the east of here is Sri Lanka, and there is the biggest manta ray fishery on the planet. NARRATOR STEVE BACKSHALL In less than a hundred years, the global population of mantas is thought to have halved. AHMED SHAMOON We have really no knowledge about what these creatures are doing when they are moving up and down on the outskirts of these atolls, so if they go out into the open ocean, and meet one of these fishermen, they're going to get into trouble. NARRATOR STEVE BACKSHALL But here, within the borders of this sanctuary, mantas can roam, find food, and reproduce in relative safety. AHMED SHAMOON The future for mantas, here in Maldives, looks good. I think it's going in the right direction. STEVE BACKSHALL What we need now, is more of the world's oceans protected as they are here. If that can happen, then there is still a future for sharks.