9 www.able.co.nz Captions were made with the support of NZ On Air. Able 2017 The world's greatest wilderness, the open ocean. It covers over half the surface of our planet. Here, there is nowhere to hide and little to eat. It's the marine equivalent of a desert. CLICKING AND SQUEAKING And patrolling this desert, spinner dolphins. They stick together... ..in a super-pod 5,000 strong. That maximises their chances of finding something to eat. Like all who live here, they must go to extraordinary lengths to make their home in the big blue. There are rare moments when these empty seas can explode with life. Lanternfish, off the Pacific coast of Costa Rica. They're scarcely bigger than minnows, but what they lack in size they make up for in numbers. They are one of the most numerous fish anywhere. Normally, they only come to the surface at night, to feed on plankton, but this immense shoal has risen during the day, almost certainly in order to spawn. For the dolphins, this would be a bonanza. CLICKING AND SQUEAKING They have located the shoal using their echo-sounding calls. But they have to get to it quickly. They are not the only hunters here. Yellowfin tuna have also detected the shoal. And behind them, with their two-metre wingspans, mobula rays. Now sailfish, one of the fastest fish in the sea, have joined the chase. The lanternfish may return to the deep at any moment. But now the dolphins have got here. They swim beneath the shoal, pinning it to the surface and forcing the lanternfish to pack more closely together. CLICKING AND SQUEAKING And now the sea begins to boil. The tuna charge into the shoal at over 60km/h. The slower-swimming rays arrive at last. With their immense mouths agape, they scoop up the lanternfish by the hundred. The shoal has now been largely dispersed, and the sailfish pick off the survivors. In just 15 minutes, all that's left is a silvery confetti of scales. But here, such feasts are only too infrequent. 9 Whilst the dolphins perform great feats of endurance, others are driven to even greater extremes to find food in this ocean desert. A sleeping giant. A sperm whale. This family is resting between bouts of feeding. Who knows what the owners of the biggest brain in the planet dream about. CLICKING One has a calf. It's about two weeks old but still dependent on its mother's milk. It's hungry. CLICKING It communicates with its mother using a pattern of clicks. CLICKING CONTINUES But its mother slumbers on. The calf, covered in sucker fish, of which it can't yet rid itself, has to be patient. Sleep over and refreshed, the whales move on. Sperm whales don't wait for their prey to rise to the surface. They swim down into the depths to find it. They take a series of heavy breaths... ..to saturate their blood with oxygen. Then down they go. This entire family dives together in search of squid. A mother will push her body to the limits of her endurance, and already it's hard for her calf to keep up with her. CLICKING The calf sticks to its mother as closely as it can... ..touching her frequently, as if for reassurance. FASTER CLICKING But 300 metres down, it seems the calf can't hold its breath any longer. CLICKING CONTINUES In their early years, calves are forced to sit out the hunt. The adults continue their dive. CLICKING The mother changes her calls into a series of louder and more rapid clicks. She's now using sonar to hunt down shoals of squid. At 800 metres, a burst of clicks. CLICKING BECOMES VERY FAST CLICKING STOPS Then silence. She's made a catch. A calf can have a long wait at the surface. A mother returns from the deep after as much as an hour. She has a stomach full of squid. Finally, this hungry calf can take some milk. It's one of the richest produced by any mammal, and the calf guzzles a bathful of it a day. It may be six years before a calf masters the art of deep diving and is able to find food for itself. The emptiness of the big blue is what makes life so hard for hunters. But it's this emptiness that makes it comparatively safe for prey. A baby turtle, hatched just days ago, is leaving the crowded, dangerous waters of the coast and heading for the open ocean. To start with, they fill their little stomachs with plankton. But soon they need something more substantial. Only recently have we begun to solve the mystery of where baby turtles disappear to in their early years. Hundreds of kilometres offshore, in every ocean, there are communities of young castaways. So anything that floats attracts them. A log. It may have been at sea for several years, and it has already become the centre of a small community. Young puffer fish are here for the same reason. A floating log is just the kind of refuge this young turtle has been looking for. Here, there's not only seaweed on which to graze, but barnacles. But it's important to stay under cover. A young ocean-going silky shark is here, too. It's learning what tastes good. And what doesn't. We now know that many young turtles stay in such places for several years, until adulthood. Even if it means facing the full force of the high seas. 9 The sun beating down on the deep blue warms the surface waters so that they evaporate. As the vapour rises, it condenses into clouds. They rapidly build into gigantic, burgeoning towers, which eventually generate violent storms, some 1,000 kilometres across. Hurricane-force winds sweep across the open ocean, building waves that can rise to 30 metres tall. Out here, ships have been known to sink without trace. 130 million containers are shipped across the oceans every year. And on average, four of them fall into the sea every day. In 1992, a few were lost that contained a consignment of bath toys... ..including 7,000 plastic ducks like these. They started their travels over 1,000 kilometres off Alaska. Some drifted right across the Pacific Ocean and reached Australia. Others were carried north and landed on shores between Russia and Alaska. They even found their way into the High Arctic. One duck, having been at sea for 15 years and crossing three oceans, eventually landed on the west coast of Scotland. Their travels vividly illustrate how a network of currents connects all our oceans into one gigantic circulatory system. Many of the inhabitants of the big blue rely on these currents to carry them to feeding grounds. The blue shark. It travels over 8,000 kilometres a year, riding on the currents, supported by its broad wing-shaped fins. This one may not have eaten for two months. But the currents can carry promising traces of fatty oils from many kilometres away and will lead it to its next meal. After days of travel, the smell of food gets stronger. A dead whale, recently struck by a ship. This could be a real feast, but the blue shark must be cautious. Great white sharks... ..ten times heavier than a blue... ..are highly possessive around a whale carcass. Great whites are eager to feed on energy-rich whale blubber, which we now know forms a major part of their diet. Once the great white has had its fill, smaller sharks, like the blue shark, tackle what's left of a carcass. As the oils from this dead whale spread more widely, more and more blue sharks appear. Within days, the carcass will be stripped of its blubber. Then, no longer kept buoyant by its oil, it will sink into the depths below. The blue, with its reserves of fat replenished, can now survive for another two months without eating. Over half of all animals in the open ocean drift in currents. Jellyfish cross entire oceans feeding on whatever happens to tangle with their tentacles. Some can grow to a metre, even two metres, across. And when, by lucky chance, they encounter a patch of sea rich in plankton, their numbers explode. It's such a successful strategy that jellies are one of the most common life forms on the planet. But among the jellies, and looking somewhat like them, is a rather more complex and sinister creature. The Portuguese man-o'-war. It floats with the help of a gas-filled bladder, topped by a vertical membrane. With that serving as a sail, it maintains a steady course through the waves. Long threads trail behind it, some as much as 30 metres long. Each is armed with many thousands of stinging cells. A single tentacle could kill a fish or, in rare cases, a human. But among its lethal tentacles lurks a man-o'-war fish that feeds by nibbling them. Whilst this fish has some resistance to the stings, it must still be extremely careful. Most other fish are not so lucky. A tentacle has caught this one and reels it in. It's already paralysed. Specialised muscular tentacles transfer the victim to others that digest the catch, liquefying it with powerful chemicals. Eventually, all that is left... ..is a scaly husk. This voracious man-o'-war may collect over 100 small fish in a day. 9 For the most part, the big blue seems featureless,... ..a place where the winds blow, uninterrupted by land. But beneath the surface there are long mountain ranges, deep trenches and isolated volcanic peaks that make it far more varied than the human eye can see. We are only just discovering in any detail how the inhabitants of the big blue exploit that. A lonely whale shark on a special journey. She is as long as a small aircraft and she weighs over 20 tonnes. Like many sharks, she does not lay eggs but gives birth to live young. She carries up to 300 of them in her swollen belly. She may be the biggest fish in the sea, but the place where whale sharks give birth has not yet been found. Today, however, we may be a step closer to solving this mystery. We have known that great numbers of whale sharks, at certain times of the year, appear around the Galapagos Islands. Here they assemble around a tiny islet that rises abruptly from particularly deep water. It's known as Darwin Island. Here, swirling currents bring up nutrients from the deep, so enriching these waters that they attract great concentrations of fish from far and wide. Thousands of hammerhead sharks also assemble here. They are nearly all female. They too, it seems, have come here to breed. The whale shark receives an extraordinary welcome. Silky sharks, themselves three metres long, bounce against her rough skin... ..perhaps to scrape off any parasites they might have. These sharks could be a danger to any newly born young. So, perhaps to avoid them, the whale shark dives... ..down to around 600 metres. And there she may release her young. In these great depths, away from the predators that hunt in the waters above, and with abundant food, her babies could grow and eventually disperse. No-one, it is true, has ever seen young ones in these little-visited depths. But the fact that hundreds of expectant whale sharks come here every year is strong evidence that somewhere here lies the nursery of the biggest fish in the sea. There are almost 30,000 sizeable islands scattered across the world's oceans. One of them is South Georgia,... ..an ideal place for those ocean dwellers who are compelled to land in order to breed. The wandering albatross. It may spend as much as a year continuously at sea,... searching for food, gliding on wings that are 3.5 metres across - the biggest of any living bird. The entire world population of 16,000 wanderers nest on South Georgia and half a dozen or so of the other smaller islands that lie in the Southern Ocean. It's spring and this bird is returning to the nest site it's always used. THEY CALL TO EACH OTHER Its lifelong partner is already here. THEY CALL AND CLUCK In South Georgia, individual birds have been studied for their entire lives, revealing that older pairs, in their late 30s, will go to extraordinary lengths to give their young the best possible start in life. This chick is now several weeks old, but still has its warm, downy coat. The chick will need a regular supply of regurgitated fish and squid. With food so scarce in the open ocean, both parents may have to scour thousands of kilometres just to provide enough for one meal. Ageing parents struggle on all through the Antarctic winter to raise a chick that is big, strong and healthy. After some 130 days, the youngster begins to replace its down with flight feathers. Finally, nine months after their egg was laid, this chick is ready to leave. Of all the chicks they've reared in recent years, such a favoured chick will have the best chance of survival. But it will also be their last. Elderly parents never recover from their exertions. They will soon leave this island, never to be seen again. 0 Surviving in the open ocean has always tested animals to the limit... ..but today they face a new additional threat. Plastic. Just over 100 years ago, we invented a wonderful new material that could be moulded into all kinds of shapes and we took great trouble to ensure that it was hard-wearing, rot-proof and virtually indestructible. Now, every year, we dump around eight million tonnes of it into the sea. Here, it entangles and drowns vast numbers of marine creatures. But it may have even more widespread and far-reaching consequences. A pod of short-finned pilot whales. THEY CLICK AND BUZZ They live together in what are, perhaps, the most closely knit of families in the whole ocean. Today, in the Atlantic waters off Europe, as elsewhere, they have to share the ocean with plastic. A mother is holding her newborn young. It's dead. She is reluctant to let it go and has been carrying it around for many days. In top predators like these, industrial chemicals can build up to lethal levels... ..and plastic could be part of the problem. As plastic breaks down, it combines with these other pollutants that are consumed by vast numbers of marine creatures. It's possible her calf may have been poisoned by her own contaminated milk. Pilot whales have big brains. They can certainly experience emotions. Judging from the behaviour of the adults, the loss of the infant has affected the entire family. Unless the flow of plastics and industrial pollution into the world's oceans is reduced, marine life will be poisoned by them for many centuries to come. The creatures that live in the big blue are perhaps more remote than any animals on the planet. But not remote enough, it seems, to escape the effects of what we are doing to their world. Next time, we journey into the bountiful green sea. These are enchanted worlds, home to strange creatures... ..where only the most ingenious will triumph.