MARK_SHARMAN RANDAL_ARAUZ ROSIE_GLOYNS STEVE_BACKSHALL UNKNOWN_MALE LAURENT_BALLESTA STEVE BACKSHALL Sharks are the most feared predators on earth. But also the most misunderstood. I've been diving with sharks for over 30 years. Now I'm getting closer than ever before. Journeying deep into our oceans to explore their hidden lives, challenging what we think we know, to better understand some of the most mysterious creatures that exist in our world. STEVE BACKSHALL There are more than 500 species of sharks in our oceans. Their bodies and behaviours all staggeringly diverse. Nowhere has more shark habitat than the largest ocean of all, the Pacific. STEVE BACKSHALL The Pacific Ocean covers an area greater than all the land on earth. For 400 million years this underwater wilderness provided sharks with everything they needed to flourish. But now their numbers are plummeting. Hidden in this huge ocean are the critical locations sharks depend on for survival. Vital places, intimately linked to their lives, where they can feed, reproduce and find sanctuary. I'm joining scientists in an urgent race to find these shark hot-spots, understand what they offer that's so important, and uncover what we can do to preserve them. STEVE BACKSHALL My journey begins at an island in the eastern Pacific. It's incredibly remote and draws in sharks in huge numbers. STEVE BACKSHALL Thirty six hours of open sea and we're here. Cocos Islands, the island of the sharks. I've waited a lifetime to get here, and we're finally here, but I'm pretty sure it's going to be worth it. STEVE BACKSHALL 550 km off the coast of Costa Rica, Cocos is a tiny speck of land, surrounded by the vastness of the Pacific. Sharks must come here because it offers them something essential. But, it's not immediately evident from above the water-line. STEVE BACKSHALL So what you can see here is actually the pinnacle, the summit of a mountain, a submerged volcanic sea mount that begins out there in the depths and then crests here above the waves. STEVE BACKSHALL To understand why a submerged volcano is a paradise for sharks I need to enter their world, and as soon as I do the answer is clear. Food. When strong Pacific currents collide with the underwater walls of the sea mount they're forced upwards, pulling up nitrates and phosphates from the sea-bed. This creates blooms of plankton that kick starts an explosion of life. STEVE BACKSHALL These sea mounts drive nutrients up from the deep seas into shallower waters. Those feed smaller fish which feed predators like the jacks. And eventually at the top of the food chain are the sharks. STEVE BACKSHALL All these fish mean predatory Pacific sharks won't be far away. STEVE BACKSHALL What is that? STEVE BACKSHALL But the first shark to appear is actually here for the plankton. STEVE BACKSHALL The biggest fish on earth. The mighty whale shark. One of the natural wonders of the world. Look at that giant silhouette the size of a bus. STEVE BACKSHALL The white spots on this female's back are as unique as a fingerprint. No two whale sharks look the same. This female and her kind are migratory feeders, and she may have travelled tens of thousands of kilometres to be here. But the vital nutrients stirred up by the sea mount mean there's an abundance of micro-organisms floating in the water here, more than enough to make her long journey worthwhile. STEVE BACKSHALL This for me is why Cocos is so special, and why we should all care about sharks. And, it's only due to havens like this that they can still survive. Thoroughly awe inspiring. STEVE BACKSHALL The presence of whale sharks, and a whole host of other species at Cocos Island, demonstrates the immeasurable value of particular places to shark lives. Thankfully in Cocos this value has been recognised and the Island is now protected. But other shark hot-spots are not so fortunate. Finding and safeguarding them is now an urgent priority for shark conservation. But sharks need more than just food to survive. The time when they most need a reliable sanctuary is when it comes to reproduction. STEVE BACKSHALL Travelling north west from Cocos, the rugged coast of California has been shaped over millennia by the relentless pounding of the Pacific. It looks rough and inhospitable, but beneath the surface it's a world apart. In these cold waters giant kelp forests thrive. These towering structures calm the pounding swell, creating an oasis for sharks to breed, and a place that protects their young. This is a swell shark, found only in the eastern Pacific. They come to these underwater forests to reproduce. But, finding a mate in the dense kelp could present a challenge. So the swell shark has found an ingenious way of signalling to a suitor. They appear to glow. STEVE BACKSHALL When the ultra violet of the sunlight hits the shark’s skin, special molecules reflect it back as green. The unique lens in a swell shark’s eye allows them to see this light. In the shelter of the kelp fronds they can find each other and mate. But this tranquil haven is vital for so much more than just finding a partner. STEVE BACKSHALL A pregnant swell shark needs to find an ideal spot to give her pups the best start in life, but unlike most sharks, she doesn't give birth to live young. This exquisite structure is a swell shark egg. Inside is a miniature miracle of nature, a tiny swell shark, no bigger than my thumb. For up to a year the egg case will cling here, surrounded by predators on the look-out for an easy meal. The only defence is staying hidden. In this patch of kelp forest, concealed in every frond is a camouflaged egg. If they're torn loose, they're quickly devoured. Those that manage to hang on finally emerge as perfect miniature copies of adults. Against the odds, they've survived. Until recently the kelp forest provided swell sharks with everything they needed for generations. But when the time comes for this little shark to have offspring, there may be nowhere safe left to hide them. STEVE BACKSHALL Warming oceans have caused kelp forests to decline by over 90% in some areas. It's an urgent reminder of why we must find, understand and protect these vital shark hot-spots, before they disappear forever, taking sharks with them. STEVE BACKSHALL In my search for these crucial places, we return to the volcanic island of Cocos, a vital staging post where we know sharks of all kinds come to feed. Seeking out reliable sources of food is a fundamental need for any animal, but there are other and surprising reasons sharks travel here. All are essential to their survival. STEVE BACKSHALL I'm looking for a shoal of fish that has a curious relationship with sharks. STEVE BACKSHALL The brightly coloured, disc-shaped fish around me are butterfly or barber fish, and they've all gathered here to provide a service to the other larger creatures. This is a cleaning station, and this lot are the ones who get to do the cleaning. STEVE BACKSHALL Keeping their bodies clean is vitally important to sharks. Scalloped hammerheads will pin-point these places and travel straight to them, even in the apparently featureless open ocean. The iconic Hammerhead is the key to their navigational prowess. Packed with electrical receptors called the ampullae of Lorenzini, it gives them a sixth sense, allowing them to pick up the earth's invisible electromagnetic fields. Iron in the rocks of underwater volcanoes like Cocos make these fields particularly strong, and this internal navigation system, like a GPS, is guiding this female in to the cleaning station. STEVE BACKSHALL As the sharks approach they rock their bodies from side to side as a signal to the smaller fish that they're ready to be cleaned. STEVE BACKSHALL The cleaner fish bravely oblige, darting in to eat dead skin and parasites, and cleaning her wounds. It's a mutually beneficial bargain. STEVE BACKSHALL It's a perfect example of symbiosis, of two animals living and working together in harmony. STEVE BACKSHALL The contented female shark is soon joined by others, and all wait patiently for their turn. STEVE BACKSHALL Most of the hammerheads here are females, so they come together, they hang out, they socialise and then they head to the cleaning station, which is kind of like a spa. This is like the ultimate hammerhead hen weekend. STEVE BACKSHALL It might seem frivolous, but parasites or infected wounds can cause blindness, debilitation and even death to sharks. These special locations are life-savers. From cleaning and feeding stations to safe havens for giving birth, sharks depend on a whole network of critical hot-spots that serve them at different stages of their lives. But, it's not always about finding the right place. Incredibly over millennia sharks have also adapted to arrive there at just the right time. STEVE BACKSHALL Heading over 6000 km into the heart of the south Pacific, you reach Fakarava, a group of isolated island atolls. Just like Cocos, this remote outpost draws in sharks from all over the Pacific by offering them something unique and vital to their survival. But what is incredible is not just how and why they travel here, but when. At Fakarave timing is everything. STEVE BACKSHALL It's the highest tide of the year and grey Reef sharks are gathering around a submerged channel. Their numbers swell into the hundreds and they hang in the current, waiting. Camouflaged grouper, usually solitary fish, are assembling in their thousands to spawn in the channel. Here the outgoing tide will transport their fertilised eggs into the deep ocean and away from predators. This synchronised event only happens for a few hours out of the whole year, and while the eggs drift safely out to sea, the sharks turn their attention to the adult grouper. STEVE BACKSHALL We know this once a year feast is vitally important to the sharks’ energetic needs, but until recently, what happened inside this cyclone of activity was a mystery. To help us help sharks, scientists need to understand events like these. A team of marine biologists and film makers, led by Laurent Ballesta, think they've found the answer. LAURENT BALLESTA Sharks are known to be like barbarians, with a little brain and just attract by blood and, and that's it, and what we saw that there, they were much more organised than we thought before. STEVE BACKSHALL By deploying state of the art underwater cameras, Laurent is able to slow down the action, and pause it entirely. What he discovered was shark behaviour that was new to science. STEVE BACKSHALL Hiding in the coral should protect the grouper from the much larger sharks, but in the melee and only revealed in super slow motion, is the grey reef sharks secret weapon. A lone white tip reef shark. It's a distant cousin of the grey reef shark and critically, just small enough to flush out the grouper from hiding. Out in the open, as the pack descends, the fish don't stand a chance. By working together and using the smaller white tips, grey reef sharks can improve their hunting success by up to 500%. This behaviour indicates intelligence, and Laurent's discoveries are re-writing our whole understanding of sharks and their abilities. LAURENT BALLESTA People are used to talk about frenzy when shark are hunting. It's not frenzy. It's harmony. STEVE BACKSHALL The island atoll of Fakarava has allowed us to see sharks in a whole new light. STEVE BACKSHALL Across the Pacific and around the world, scientists are doing similar work. They're uncovering how and when sharks use specific locations, in the hope this knowledge can help us protect them, and the cause has never been more urgent. STEVE BACKSHALL With unknown hundreds of millions of sharks being taken from our oceans every single year, we've lost at least 71% of oceanic sharks and rays within my lifetime. These animals that started evolving before the dinosaurs and outlasted them, could go extinct within a single generation of humans. STEVE BACKSHALL I've seen first-hand what sharks are up against. They face warming seas and the collapse of ocean eco-systems upon which they rely. But, by far the biggest threat comes from fishing. Whether targeted directly or caught by mistake as boats trawl for other species, the impact on shark numbers is shocking. Nowhere is the threat more severe than in the Pacific, one of the most intensely fished oceans on earth. To understand what we can do to reverse this trend, I'm travelling to Revillagigedo Archipelago, an area 630 km west of Mexico, and the tiny tip of a vast submerged volcano. STEVE BACKSHALL Roca Partida is the most obvious and dramatic oceanic sea mount you'll ever see. It's a full day steaming in any direction before you reach land, and very close to here is the deep, the abyss, 3700 m of depth. STEVE BACKSHALL This small island is part of a sizeable solution. The largest protected area in north American where fishing of any kind is banned. Under the water the results are clear to see. STEVE BACKSHALL From wing tip to wing tip they could be eight metres across. STEVE BACKSHALL In other parts of the Pacific these giant oceanic mantas, close cousins of sharks, are hunted by people. The hunting and their slow rate of reproduction is the reason these gentle giants are now globally endangered. But the protected waters around Roca Partida offer these migratory marvels a safe space to feed and recuperate without persecution, and they're not the only ones. STEVE BACKSHALL Silky sharks in a vast shoal. There could be a hundred animals, in a world where sharks are on the brink of extinction. To see a sight like this is phenomenally rare. STEVE BACKSHALL Silkies criss-cross the Pacific, running the gauntlet of fishing vessels that either hunt them directly for their fins, or catch them unintentionally when they're pulling in tuna. The migratory lifestyle of mantas and silkies mean they're just passing visitors to Roca Partida. But, there are sharks that can take advantage of this protected place for their entire lives. STEVE BACKSHALL Every single ledge and crack and crevice is packed with white tip reef sharks, all lodged in together like sardines in a can. I guess this doesn't fit with many peoples idea of what a shark is. You expect them to be menacing, active predators, not cuddled together like a family on the sofa after Sunday lunch. Some of them are no longer than my forearms, They're pups, the original baby sharks. They've probably only been born a couple of weeks ago. STEVE BACKSHALL White tip reef sharks are able to swim at birth, and must fend for themselves with no protection from parents. Whether for safety or just comfort these infants snuggle together in a sheltered nursery. One youngster takes a brief foray away from his balcony. The open ocean is a dangerous place for a little shark, but he soon returns. He is one of the lucky ones. The island can provide everything he needs throughout his life, giving him no reason to venture beyond its protective boundaries. STEVE BACKSHALL All this staggering diversity thrives at Roca Partida because it is protected. It's a pillar of hope for sharks, standing strong in the eastern Pacific. STEVE BACKSHALL Sanctuaries and safe spots are critical for sharks. But I want to know how supersized protected areas play a role in preserving shark diversity. STEVE BACKSHALL In the far west of the Pacific, one of the most famous marine sanctuaries in the world, the Great Barrier Reef, may hold some answers. It doesn’t just safeguard sharks, it creates a refuge for all marine creatures. STEVE BACKSHALL The Great Barrier Reef is the largest living structure on Earth, stretching almost 2300 km along Australia's east coast, and for more than 40 years, much of it has been protected. While it cannot be fully shielded from climate change, these protections mean it's home to more than 9000 species, and Australia has more types of sharks and rays than anywhere else. STEVE BACKSHALL There's one shark here that shows just how extraordinary that diversity can be. The epaulette shark. All that life on the reef means fierce competition for resources, but this unassumingly small shark has a skill so surprising he blows the competition out of the water. Twice a day the tide retreats, leaving isolated pools separated by jagged sections of exposed reef. Other sharks disappear with the water, to avoid stranding themselves on the exposed coral. But not the Epaulette. In a vanishing puddle he flaps his gills a final time. But this is no dying breath. STEVE BACKSHALL His gills don't work out of water, but by slowing his heart rate to half the number of beats, and shutting down his internal organs, he can survive for up to an hour. And then, he does something even more astonishing for a fish. He walks. Using his fins as feet, he makes his way across the jagged coral. It might seem like a titanic struggle, but in this competitive environment it's a smart strategy. The prize for his achievement? A private pool where he and he alone can be top predator. STEVE BACKSHALL This incredible adaptation is evidence of the extreme diversity of sharks. Diversity that will only persist if we protect the habitats and places they rely on to feed, breed and stay healthy. But, safe havens like the Great Barrier Reef are few and far between. The overwhelming majority of the Pacific Ocean, more than 90% of it, is totally unprotected. On the next part of my journey I'm exploring the waters surrounding Cocos Island, joining the Shark Water Research Team, as they try to answer possibly the most important question of all for sharks, what happens when they leave protected areas? Leading the project is renown shark scientist, RANDAL ARAUZ. RANDAL ARAUZ If the animals are moving between these sea mounts and we're allowing fishing right in her, well they're going to get fished out. And we need, we definitely need more efficient management and conservation programs, based on the science. STEVE BACKSHALL Randall and his team are studying scalloped hammerheads as they leave the protected waters around Cocos and head out into the pacific. They're gathering strong evidence that suggest hammerheads use a specific route to move between key locations. STEVE BACKSHALL Looking at the topography here, the undersea topography, it appears that you've got big areas of great deep sea and then there's these ridges, aren't they. RANDAL ARAUZ Well, we, we have the, the evidence at least of the sharks moving from Cocos to Galapagos and they're travelling right along the submerged Cocos ridge. So there's a mountain down here underneath, which is highly magnetic and it's believed that they're actually following the magnetic fields of the earth, so we're calling this the Cocos-Galapagos swim way. STEVE BACKSHALL The hammerheads’ route is taking them through heavily fished waters. This could be the reason they are declining so rapidly. RANDAL ARAUZ Hammerhead sharks were declared critically endangered last December, and that means that if we don't change our ways that we've been warning for the last 34 years, if we continue this way for the next 20, hammerhead sharks are going to disappear within our life time. STEVE BACKSHALL If they can gather enough proof, Randall hopes to convince Governments, not just to protect shark sanctuaries, but critically to also protect the highways between them. Today's task is to attach a transmitter to a scalloped hammerhead. Tracking the shark's movements will add to the team’s evidence. STEVE BACKSHALL So Randall, what's our plan? RANDAL ARAUZ Okay, well we're going to go down to about 15-20 m, look for a cleaning station. Then we're going to sit there and wait for a shark and see if we're able to tag one. STEVE BACKSHALL On the end of this pole is the tracking device which will record the shark's every move for up to ten years. My task is to measure the size of the tagged shark, which will help estimate the age. STEVE BACKSHALL The beams stay constant, so if you can put them onto the side of a shark, you can get a sense of how big they are. STEVE BACKSHALL This one is about 3 m long, a fully mature female, probably about 16 years old. She's keeping her distance, but we need one within a few metres if we're to attach the tag. Randall sees his chance. STEVE BACKSHALL Amazing! Straight by the dorsal fin, that's brilliant. Hopefully that tag and the transmitter will be giving us information about that shark and where he goes. All this information is going to lead back into a better understanding of this species and its migratory patterns and that will help us learn how to protect them. STEVE BACKSHALL The tag won't harm the shark but it might just secure his future. Cocos is famed for being a sight where hammerheads gather in incredible numbers and as I watch our shark depart, I see he's joined by many more of his kind. STEVE BACKSHALL When you first look, you can see 20 or 30 but then when your eye gets in, you can see there are several hundred animals. This is truly one of the greatest aggregations of large predators on Earth. STEVE BACKSHALL The rare and magical gathering of hammerheads is thought to be part of an elaborate mating ritual. Somewhere among them is our shark, carrying his beacon of hope. STEVE BACKSHALL Sea mounts like Cocos are so important to the survival of species like scalloped hammerheads. Without them they simply would not have a future. But what's critical is what happens when they swim beyond these protected seas and out into the open ocean. STEVE BACKSHALL My journey into the secret lives of sharks has taken me deep into our three mightiest oceans. I've seen how this incredible animal group is perfectly honed to thrive, but I've witnessed their world changing at an alarming rate. Yet it's still left me with hope. While we may be responsible for their problems, we also hold in our hands the possibility of their survival. The remarkable story of sharks doesn't have to end here. STEVE BACKSHALL During the making of the Pacific episode, we were reminded just how difficult filming sharks can be. The most challenging shoot was the remote island of Cocos off the coast of Costa Rica. Here, we hoped to film the critically endangered Scalloped Hammerhead. We took six film makers, two tons of kit and a team of scientists. STEVE BACKSHALL 36 hours of travel and there it is, Cocos Islands. STEVE BACKSHALL This uninhabited jungle clad outcrop inspired the movie, Jurassic Park. And its wild waters are thought to be the best place to film schooling hammerheads. Our base is a refurbished fishing boat, called Shark Water. It's now state of the art and is used for shark research and conservation. Heading up the science team is world renowned shark expert, RANDAL ARAUZ. RANDAL ARAUZ This boat seems to be redeeming itself, sure, it used to be a Japanese fishing boat, now it's working for the conservation of sharks. What a great story. STEVE BACKSHALL Also on board, is award winning camera operator, MARK SHARMAN. He's no stranger to the challenges of filming sharks. MARK SHARMAN When you've got a big camera to actually get in those positions and allow them to keep on behaving naturally, it is extremely difficult and it takes a lot of patience and a lot of dives to get right. STEVE BACKSHALL Randall advises us to focus on diving around an outlining rock, where he's seen hammerheads gathering in numbers on previous research trips. STEVE BACKSHALL The big challenge with this, this that you just can't predict it. The only thing we can do is hit is as many times as we can and hope for the best. UNKNOWN MALE Three, two, one! STEVE BACKSHALL Mark and I both have a safety diver, are armed with an ultra high definition camera and have a comms link to the director, ROSIE GLOYNS, on the surface. ROSIE GLOYNS Dive team, dive team, this is topside. STEVE BACKSHALL Steve here. All is well down here. We're heading down the slopes of the sea mountain to deep water and I can see off in the blue already, the shape of sharks. STEVE BACKSHALL Hammerheads migrate thousands of kilometres across this vast ocean, moving between feeding sites, nursery grounds and meeting places, like this one. They sometimes gather in huge numbers, but we have no way of knowing if, or when, they're going to show up. ROSIE GLOYNS It feels like a bit of a dark art, getting in the right place at the right place at the right time with the hammerheads and it seems they like current, but not too much current. They like cold water, but not too cold, they like overcast days so we're hoping today might be good. STEVE BACKSHALL The sharks that are here appear to be keeping their distance. STEVE BACKSHALL I think maybe our best bet is to tuck ourselves into a side and try and create as small in impression as possible, so as not to put the sharks off. STEVE BACKSHALL With the team concealed, the hammerheads are coming closer. STEVE BACKSHALL And we get a unique view of some of their most intimate moments. But just as we feel we're getting somewhere-- STEVE BACKSHALL Whoa! What happened there? All of a sudden, five or six of them just rocketed out, something really spooked them. STEVE BACKSHALL But this time, it's not us. STEVE BACKSHALL More! More! More! More! Dolphins above us! [LAUGHS]. And the second the dolphins started calling and turned up, all the sharks just disappeared. STEVE BACKSHALL It's clear that the hammerheads are scared of dolphins as well as divers. We've now got lots of dolphins but no hammerheads. STEVE BACKSHALL For hundreds of years, mariners and shipwreck victims have told stories of having their lives saved when dolphins turn up and scare away the sharks. We could possibly be the first team in human history to be hoping it's the other way around. We don't want the dolphins turning up and scaring the sharks away. STEVE BACKSHALL Capturing the spectacle of schooling hammerheads is a tall order. Hammerheads are reported to gather at Cocos for four months each year, but this coincides with rainy season and some of the most dramatic weather the Pacific has to offer STEVE BACKSHALL We have at very least, a big low pressure system hanging over us, it could even be a tropical cyclone. We are really gonna have to be on our game now. STEVE BACKSHALL Diving in a remove location is challenging and diving in these conditions raises the stakes considerably. With limited visibility, the chances of the team getting separated and pulled out to sea by strong currents, are higher. STEVE BACKSHALL But, despite the conditions, we know the more time we spend underwater, the better our hopes of filming a huge school of hammerheads. So we dive. STEVE BACKSHALL Come to Costa Rica they said. STEVE BACKSHALL Tropical island paradise, they said. STEVE BACKSHALL Sun, sea, sand. STEVE BACKSHALL And our filming window seems to be ebbing away. STEVE BACKSHALL One of those days Marky, just one of those days. STEVE BACKSHALL But as days roll on, I wonder whether we haven't encountered these critically endangered hammerheads in numbers because they just aren't here anymore. Over the 16 years Randall's been diving at Cocos, he's seen first hand how numbers have declined. RANDAL ARAUZ Well, the first times I came to Cocos Island in 2004, you would see the clouds of hammerhead sharks and you would try to count them and you would lose track after about 150 or 160 sharks. Nowadays, there are way fewer sharks and we gotta get moving, we have to basically stop killing so many of them. STEVE BACKSHALL Hammerheads are being fished in their millions, when they leave protective areas like Cocos. Scientists have calculated a 90% decline, making mass schooling events even rarer than they used to be. This makes us even more determined to capture this event before it's too late. STEVE BACKSHALL Hammerheads are being fished in their millions, when they leave protective areas like Cocos. Scientists have calculated a 90% decline, making mass schooling events even rarer than they used to be. This makes us even more determined to capture this event before it's too late. STEVE BACKSHALL This is the one. Huge, huge shoal, coming in from the right hand side, huge shoal. You see this, Mark? Wow! Oh, wow, that is a lotta sharks! STEVE BACKSHALL Finally, after spending 30 hours under the water, it looks like we're in the right place at the right time. Hammerheads are gathering in their hundreds. STEVE BACKSHALL Whoa-ho-ho! No way! That is utterly incredible! STEVE BACKSHALL Capturing moments like this gives us a window into the complex lives of these critically endangered sharks and allows us to share their incredible story. STEVE BACKSHALL It's one of the most awe inspiring sights in nature and I feel truly humbled to have been a part of it.