"It is November." "A full moon rises." "Almost 400,000 kilometers away, Planet Earth falls under its spell." "Our oceans stir." "An ancient undersea ritual is underway." "The outcome of this event will not only affect marine life in the surrounding waters, but will also give us a clue about the health of the entire ocean system." "The creature responsible is coral." "And this is coral's story." "The story begins here, with the incredible phenomenon that is mass coral spawning." "It's an annual event, cued by the sun and the moon." "It involves over 140 different species, and has been occurring for thousands of years." "Although corals have no brain and no eyes, somehow individual species spawn together, sometimes down to the minute." "Like tiny love-letters, the genetic material is cast into the ocean currents, connecting reefs over hundreds of kilometers." "Like us, corals take up to nine months to prepare for birth." "But many are hermaphrodites, so they gestate both egg and sperm." "On spawning night, these are grouped into bundles and delivered through the coral's mouth." "For most, it's a gentle birth." "Over a short time-span, the bundles break apart and the egg and sperm must find their counterparts from another colony." "Billions set forth, but few survive." "Many other creatures choose the same conditions to spawn and the reef waters are transformed into a vast liquid womb, clouded with eggs and sperm." "Mass spawning overwhelms potential predators, so the coral eggs have more chance to be fertilized and begin a new colony." "By daybreak, vast slicks on the surface mark their passage." "Coral is an architect not only of the undersea world, but above the surface too." "Dead coral breaks down into sand that eventually builds up to create coral cays." "These shores and shallows provide sanctuary - and important breeding grounds - for a variety of other creatures." "All told, reef-building corals have colonized every tropical ocean, shaped and protected thousands of kilometers of coastline and influenced marine evolution for millions of years." "Birds like these noddy terns rely on coral reefs for food and coral cays for shelter." "Birds help vegetate cays by depositing seeds." "These seeds grow into trees and forests which in turn provide the birds with nesting sites." "These sandy outposts are frequented by many tropical seabirds, with some pairs returning to the same nesting sites year after year." "Primitive corals date back over 450 million years." "Modern reef-building corals first emerged around 250 million years ago and their reefs have provided homes and sustenance for innumerable species ever since." "Over coral's long history, five mass extinctions have come and gone." "During each, up to 90% of all life-forms perished." "Two of these extinctions occurred during the rise of modern reef-building corals." "Rather than falter, they somehow survived, rebuilt their reefs and transformed the oceans anew." "Today, coral reef ecosystems are important nursery grounds for many iconic marine animals, such as the sea turtle." "There are seven species of sea turtle and all are long-lived and slow-growing." "They take between l 0 to 30 years to sexually mature and mate at sea." "These marine reptiles are nomadic and swim thousands of kilometers during their lives." "But strong instinct and mysterious natural forces guide them, so that when a female needs to lay her eggs, she returns to the very beach where she was born to do so." "Here, she digs a nest and coral sand becomes the womb." "Hundreds hatch, but only one or two will make it to adulthood." "They can then live for up to a century." "When a turtle hatched 1 00 years ago, it would have seen the world's coral reefs in all their glory." "Pre-industrial seas were clean and clear and corals had enjoyed good conditions for millions of years." "Throughout the Indian and Pacific oceans, and into the Caribbean and west Atlantic, reefs were thriving." "The turtle spent its youth exploring these reefs and witnessed the engineering marvel that is coral." "By harnessing the power of the sun and perfecting recycling, coral built energy-efficient cities that put many of ours to shame." "Collectively, these cities created vast empires, some visible from outer space." "Here, the turtle found itself in great company, for these undersea empires were home to vast numbers of marine species of every imaginable shape and size and were crowded, colorful places." "Today, reefs have one of the highest levels of biodiversity of any ecosystem and are some of the most biologically important places on Earth." "Together, turtles and corals have witnessed many changes to their watery world." "They are some of the only beings to have survived the last mass extinction event" "65 million years ago." "Scientists predict that in the coming century, they will face ocean conditions as catastrophic as during that last extinction." "Wise old turtles have seen the warning signs for a while." "70% of the world's reefs have already been destroyed or are seriously threatened." "And all but one of the seven sea turtle species are classified 'endangered' or 'critically endangered'." "For the first time in millions of years, the future of both turtle and coral is uncertain." "Many things affect the health of coral reefs, in particular, sea temperature, sea level and water chemistry." "Reefs may look mighty, but corals themselves are fragile and can be fatally harmed by just subtle changes in their environment." "When sea levels rise too rapidly, corals can't grow fast enough and reefs drown." "As atmospheric carbon dioxide levels increase, ocean acidification intensifies and reefs will dissolve." "And a sustained increase of only 1-2 degrees in ocean temperature can cause corals to bleach and die." "By the end of this century, it's predicted that the global climate could be 5 degrees Celsius hotter or more." "At this rate, bleaching will become an annual occurrence, and this colorful landscape will literally fade away." "A healthy coral reef is easy to spot." "A complex structure awash with color, variety and activity." "This is a tangled, tropical garden to rival anything on land." "Most amazing about this garden is that many of the 'plants' are actually animals." "Like grasping hands, coral mouths hungrily sift the passing currents for food day and night." "The creature we call 'coral' is a primitive sac-like polyp, part animal, part plant." "The animal part feeds on plankton." "The plant part consists of microscopic algae - called zooxanthellaethat photosynthesize using sunlight." "Each polyp is connected to its neighbor passing along energy and nutrients." "These polyps multiply to create colonies, which combine to form reefs." "In this way, energy is produced, shared and recycled throughout the entire ecosystem." "With the energy they produce, corals not only thrive but also manufacture calcium carbonate, the special 'concrete' that builds reefs." "This is one secret behind corals' great empire building." "The other is budding." "Budding is a process where coral polyps produce genetically identical copies of themselves and extend their colonies without spawning." "The calcium carbonate foundation secreted by hard corals can be one kilometer thick in p laces and hundreds of thousands of years old." "The living reef we see today is just a thin veneer on top, made up of many different species, including soft corals ..." ".. fan corals ..." ".. and sponges, gorgonians and crinoids." "All told, coral has evolved into more than 1,000 hard coral species and over 700 soft coral s, each perfectly specialized to fill its own niche." "Understanding how corals build reefs highlights the seriousness of climate change and how it threatens this complex ecosystem." "Our oceans have always absorbed atmospheric C02 like a giant sponge." "But now those levels are so high that the water chemistry is changing - a process referred to as 'ocean acidification'." "Alkalinity is falling and naturally-occurring carbonate ions are being affected." "Many marine creatures need these ions to produce calcium carbonate for their shells and skeletons." "Hard corals need them to build reefs." "Ocean acidification seriously threatens all these processes." "But in every natural catastrophe, there are winners and losers." "Jellyfish are distant relatives of coral, but unlike coral, they are more adaptable to changes in water temperature and chemistry." "Their numbers are already on the rise." "And they are making our seas sting." "Coral's other ancient cousin is the sea anemone." "Like coral, the anemone is a simple being that has been highly successful." "In fact, the anemone is like a huge coral polyp." "At its center is a mouth surrounded by a vast mantle of stinging tentacles." "Within the mouth is a big stomach filled with acidic enzymes." "Because the anemone does not have a solid physical structure or skeleton, it does not rely on calcium carbonate, so it's not as vulnerable as coral to ocean acidification." "But, like coral some species possess zooxanthellae algae and warming seas will also cause them to bleach." "There are over 800 species of sea anemone." "1 0 are suitable homes for anemone fish and this is one of the reef's most marvelous partnerships." "The anemone's tentacles normally sting invaders." "But these fish are coated with a protective mucus and can dance in and out unharmed." "The fish rarely wander more than a meter away." "Everything they need is right here - scraps of food, protection and community." "Not surprisingly, the fish lay their eggs near the protective folds of the anemone, aerating and defending them until they hatch." "And being stuck in one place hasn't harmed their sex life." "In fact, it's enhanced it." "To keep everyone satisfied, they've mastered sex change." "If a dominant female is required, a male can change sex." "If a dominant male is needed, a subordinate male accelerates into sexual maturity." "As ocean conditions change, anemone fish seem more protected than most, safe within those stinging arms." "But even they are not immune from danger." "All fish have internal structures and organs which may be weakened by ocean acidification." "Even now, scientists are finding that the ear bones of fish are being affected, which is impacting the way they communicate." "If ocean acidification goes unchecked, it may affect key metabolic processes for all marine animals." "Whenever conditions get more challenging, the natural process of selection just gets more ruthless." "Those that cannot cope will be quickly cast aside." "Every citizen must earn its keep." "These shrimp gather in locations referred to as 'cleaning stations'." "This particular station also happens to be the home of a moray eel." "But the shrimp aren't running away." "If anything, they're competing to get closer." "And although the eel finds the shrimp irritating, he just grins and bears it." "The reason why these entirely different species tolerate one another is because they have an unspoken agreement." "The shrimp has the important job of removing parasites as well as dying or dead flesh." "These can be fatal to the moray, but provide a delicious banquet for the shrimp." "Animals are engaged in complex relationships right across the reef." "Going solo is risky business." "And if you're going to attempt it, you'd better be very clever." "One clever survival tactic is camouflage." "Decorator crabs attach tiny sponges, corals and anemones to their shells and look more like walking flowerbeds than animals." "Others attempt to go incognito by placing toxic sponges on their heads, like these aptly-named hat-carrying crabs." "Sponges are living creatures, but the crab doesn't care, cutting the sponge up into whatever size fits." "Other crabs collect forest leaves and use them for disguise and as hang-gliders." "Boxer crabs are always ready for a fight, with tiny poisonous anemones as boxing gloves." "Hermit crabs reinforce their own body armor by wearing second-hand shells." "Bigger shells must be found as the era b grows and this gives the crab lots of time to develop its own unique look." "More sophisticated hermit crabs collect stinging anemones and will remove these anemones and reattach them whenever they change shells." "Crabs date back to Jurassic times 200 million years ago and over 1 0,000 species exist." "They're hardy souls - even missing half their legs won't slow them down." "And they're great opportunists - some feasting inside a sea cucumber's mouth." "Sea cucumbers have some remarkable physical adaptations themselves." "They breathe through their rear end, move on hydraulically-powered tube feet, and have a special collagen in their body wall that enables them to radically change shape." "They also spawn from their forehead." "Sea cucumbers have few natural predators." "So it's no wonder they're a popular taxi ride for crabs and shrimp." "Because the sea cucumber stirs up food with its front end, there's even a free meal as part of the ticket." "Nudibranchs are also great to hitchhike." "These highly poisonous sea slugs offer guaranteed safe passage through dangerous open territory, with the shrimps scavenging on the run." "But for first-class travel, nothing compares to a jet-propelled jellyfish." "Magic carpets also glide above the reef, in the form of flatworms." "Flatworms and nudibranchs don't have shells, so draw on chemical warfare as defense." "Some eat toxic hydroids and anemones and sequester poison in their skin, which in turn makes them poisonous to any potential predator." "They advertise their toxicity with bright, bold colors and patterns, which have conspired to make them incredibly beautiful." "They are as wild in character as they are in appearance." "They have gills on their backs, sex organs on their sides and all of them are hermaphrodites." "And some are fierce cannibals." "Trying to eat your lover during sex is not quite acceptable, but snacking on a cousin is fine." "Joining the sea slugs on the ocean's floor are the sea stars." "Sea stars are often referred to as starfish, but they're not fish at all, they're echinoderms." "Echinoderms date back over 500 million years, so predate the evolution of coral." "They have evolved into a wide range of life forms and what many have in common is the spine." "Urchins are some of the most heavily spined of all, but for some color-coordinated crabs and shrimp, this isn't a deterrent." "They've adapted to live amongst the spines and remain there all their lives." "It's a classic case of symbiosis on a reef and worlds within worlds." "Tropical oceans are like vast blue deserts and largely nutrient poor." "On coral reefs, nothing goes to waste." "Various specialist filter feeders have evolved to sift the passing currents - capturing, digesting and recycling every available bit of food." "Worms are among the most numerous and diverse of all filter feeders." "20,000 marine species exist and, unlike the earth worms, they're an exotic bunch." "Befitting their name," "Christmas-tree worms unfurl festive, feathery mouth parts, which they use like tiny nets." "Their bodies, meanwhile, are buried in the coral and rarely seen." "Equally shy are ribbon eels." "They spend most of their time concealed in deep burrows, with just their heads peeking out." "They're relatives of moray eels and their gaping mouths make them look aggressive." "But they're simply breathing, with their exaggerated nostrils sniffing for food." "Adopting the same lifestyle are garden eels." "These delicate sea serpents rise from the sand in vast communities, performing their hypnotic Indian snake dance." "Ever watchful for predators, they nervously pluck plankton from passing currents, their tails anchoring them down." "Because of corals/ longevity on our planet they're considered our living fossils." "Another living fossil still with us today is the nautilus." "It's an ancient mollusk, whose line eventually dropped its shell. .." ".. and gave rise to the age of the cephalopods." "Cephalopods are synonymous with the reef and one of the most intriguing is the mimic octopus." "As its name implies, the octopus mimics the physical likeness and movements of more than 15 different species, including sea snakes, lionfish, flounder and ghost crabs." "It's one of nature's great contortionists." "If it doesn't want to be seen, it certainly won't be." "Many species of octopus live in the vicinity of reefs and a true reef specialist is this - the day octopus." "These octopus are great hunters and fish hurry to defend their eggs." "And being so tasty themselves, octopus have had to develop excellent martial arts skills." "They have the most complex brain of any invertebrate and can process information from all eight arms at once." "They have short as well as long-term memory and possess a special way to communicate with their skin." "They're also highly interactive and tactile." "Courtship rituals can last for hours, with couples intertwining all 16 arms in a sticky embrace." "Once they mate, their bodies are programmed to die." "For some species, this means a lifespan of just 6 months." "For others, up to 5 years." "Cousin of the octopus is the squid, seen here delicately laying eggs in forest fronds." "We know squid more commonly as calamari, but despite being a favored delicacy around the world, many species are increasing in number." "Like other cephalopods, they're making the most of oceans depleted of natural predators and seem more resilient than others to changing water conditions." "Another charismatic member of the family is the cuttlefish ." "These creatures have magical attributes." "On the outside, large eyes as expressive as our own." "On the inside, three hearts that pump blue blood." "During their breeding season, they gather in small groups, zooming amongst one another like miniature spaceships." "Masters of jet propulsion, they can move backwards, forwards or sideways with equal ease." "Every year they return to favorite nesting sites, like this colony of venomous fire coral." "Males use dramatic body displays and postures to compete for mating rights." "So although competition is intense, it's rarely physical." "Clutching her brood of eggs in her mouth, a female surrenders her young to the care of coral." "The flamboyant cuttlefish is one of the tiniest cephalopods, yet lives up to its name." "Its cuttlebone is too small to float, so it walks more than swims." "And it has a highly poisonous flesh, advertised by its pulsing skin." "It's also a deadly predator." "Two specialized tentacles are contained within a muscular sleeve, which is launched like a spear." "With this kind of hunting prowess, it's no wonder the cephalopods have been such a success story on the reef and will no doubt rule the seabed for eons to come." "Reefs are not only important to their permanent residents, but also to many oceanic visitors." "Strong currents and rich upwellings of food often occur around reefs and attract nomads such as rays." "In fact, the total number of marine creatures dependent on coral reefs is immeasurable." "Perhaps as many as seven million species coexist here." "Over 4,000 species of tropical fish are associated with coral reefs, of which 75% depend on the reef for their survival." "They may look like just colorful confetti, but each fish is its own individual." "Fish can smell, hear, see and touch." "They feel pain and have complex relationships." "The vast majority of reef fish have defined home ranges." "The reef sustains them, houses them and conceals them from predators." "Like tiny kites on invisible strings, the fish hover above their beloved reefs, venturing only far enough to snatch a meal, but otherwise inseparable." "The connection between fish and coral is one of nature's most enduring love stories." "Humans too benefit from a healthy relationship with coral and the seas at large." "Reefs create barriers to the sea and protect shorelines." "Various life-saving medicines are extracted from reefs." "Ocean-derived chemicals are used to treat many illnesses, including cancer." "Microscopic marine algae processes our atmospheric C02 and produces 70% of the oxygen we breathe." "So, like these fish, we need healthy oceans to survive and reefs to secure our homes." "In both our terrestrial world and the undersea, there have been constant cycles of creation and destruction." "The rule of nature is chaos." "Although a reef looks harmonious, it's as chaotic as any other ecosystem." "And one of the ways to survive chaos, whether you're above or below the surface, is to cooperate." "This cooperation is called symbiosis, a mutually beneficial relationship between two entirely different species." "These little blue and black striped wrasse would be perfect fish food if they hadn't made themselves so useful." "They're cleaner wrasse and earn their keep by cleaning." "So vital is this service that none of their grateful hosts would ever dare to eat them." "Both parties benefit and a form of balance is achieved." "There is constant tension on the reef as different species work out this balance and try to maximize their moment in history." "For some of the bigger fish, that moment used to stretch into decades." "Some even lived for a century or more." "But old age is a rarity now and iconic reef species are vanishing even as we watch." "Angelfish live for l 0 to 15 years in the wild and are some of the reef's most recognizable species." "They are highly prized by collectors and, tragically, many live out their long lives in aquaria." "A fish in a tank is like a bird in a cage - we're able to observe them but we get little idea of their wildness." "It's only here, on the reef, that we can truly appreciate just how complex a fish's life can be." "Some angelfish are promiscuous, some bond for life, others have male-driven harems." "And many fish, including these delicate leafed scorpionfish, engage in long courtship rituals." "New species of fish are dis covered every week, and with each discovery comes a wealth of new information." "Some spawn daily, others do not begin breeding until they are 20 or 30 years old." "Many start life as a male but die a female." "Most are highly social and have intelligence beyond our comprehension." "Like wildebeest and zebra on the African plains, tangs and parrotfish often graze together." "Both fish are herbivores and dine on algae and even live coral." "Other species converge on the reef crest." "This area is exposed to wave action and lots of sunlight and is rich in nutrients." "Fish like this rock-mover wrasse literally move rocks in the search of worms and mollusks." "Dining this way is hard work, and they're not always willing to share their patch." "Others excavate the substrate and swallow large mouthfuls of sand." "Their bodies are specially designed to filter the sand for algae, dispelling waste through their gills." "Access to the reef crest is limited." "It's only at certain tides and during calm seas that it's possible to feed here." "When all the conditions are right, fish arrive from miles around to take advantage of this rare opportunity." "Some are in couples, others dine alone, and completely different species feed side by side." "It's biodiversity at its best." "Eccentric earth-movers, like triggerfish, also join the dinner party." "They use their powerful beaks to cast aside whole chunks of coral, as they search for clams, shrimp and crabs." "They're much too busy to worry about their table manners." "Like a human city, a reef boasts an eclectic jumble of characters conducting themselves in a variety of ways." "There are loners and drifters." "There are clandestine meetings and underground movements." "There are the watchful and the wary." "And different forms of self-expression." "As in all of our cities, strange alliances occur ..." ".. and odd fashion is tolerated." "Every beauty and beast has its place." "Just like the terrestrial world, a reef has a 24-hour cycle." "As the afternoon light begins to fade, fish, like these anthias, spawn with abandon, knowing that night will soon follow and conceal their eggs." "Meanwhile, tiny fish shudder their bodies, indicating their readiness to mate." "And countless other daytime fish are inspired by the waning light to court or breed ." "Here, a pair of flutemouths engage in a seductive sword dance." "It's their form of foreplay, and they've been at it for hours." "Over the millennia, the battle between predator and prey has fueled an evolutionary arms race under the sea." "Mother Nature is always updating her designs and making old ones redundant." "Animals have had to constantly refine their offensive and defensive capabilities." "The result can be pure science fiction." "Angler and scorpion fish are as bizarre as they come." "They're expert mimics of sponges, but have one of the fastest strikes on Earth." "But they're certainly not out to win a beauty prize." "When it comes to some of these creations, love is certainly blind." "This myriad life has enthralled us since the beginning of human history." "We did originally evolve from the sea ." "And ever since early humans first emerged, we've been drawn back to its shores." "Seafood has been a favored diet." "Shells have been our money and jewelry." "Coral limestone paves our roads." "Sand cements our houses." "Our myths and legends, books and films are all full of characters derived from the sea." "And as light fades, these characters begin to change and the story of coral moves into a very different narrative." "Big predatory fish cruise the reef's edge, searching for a final kill." "Daytime fish hurry into hiding." "This is a dangerous time of transition ." "All across the reef, there is a changing of the guard." "The night shift has begun." "Little is known about our oceans." "The surface of Mars is better mapped." "Most living coral reefs descend to only 50 meters or so, due to the reliance on sunlight." "But the seafloor falls to 11 kilometers in places." "This is what we call the abyss." "Night-time on the reef gives us a sense of what this abyss might be like." "The inky black is very much alive and full of aliens." "In special places where reefs drop to great depth, deep sea plankton rise to the surface to hunt shallow water phytoplankton." "They travel hundreds of meters." "They number in their billions and they repeat the journey every night." "It's one of the biggest migrations in the animal kingdom." "The chase of plankton-hunter and plankton-prey triggers a larger chain reaction right across the night-time reef." "Baitfish snatch mouthfuls, while basking stars emerge from their lairs and extend web-like arms." "The water flashes with color as the plankton frantically communicate with one another." "Coral is not an idle bystander." "The reef has become a wall of mouths." "The true animal nature of coral is revealed." "Equipped with poisonous harpoons and acid, each polyp becomes a deadly trap from which escape is impossible." "Meanwhile, catfish eat on the run." "Parrotfish sleep with eyes wide open or conceal themselves in mucus cocoons." "Without torches, humans are blind at night." "Underwater, we'd barely know up from down." "But the undersea hunters are not at all disadvantaged." "Instead of sight, they use vibration, electrical impulses and chemical traces to find what they're after." "Stone walls are, in fact, living stonefish waiting in ambush ..." ".. while the sharp teeth of stargazers lurk beneath the muck." "It's easy to swim towards danger without realizing it." "This anemone has become a serial killer." "A lucky squid escapes, releasing ink to cover its tracks." "A pipefish looks on, as fish scatter and more fall victim." "Down on the seabed, scavengers collect the scraps ..." ".. while lionfish use their long spines to herd unsuspecting prey." "There is activity in all directions, as night hunters of every description eat their fill." "The anglerfish is back and now completely in its element." "It may not move with grace, but that doesn't affect its chances for a kill." "All it needs to do is wait for a meal to come to its mouth." "When it comes to nocturnal hunting, moray eels are known for their viciousness." "But other killers are not so easy to spot." "Mantis shrimp are sophisticated and savage." "They're armed with supreme eyesight and actively hunt live prey while other crustaceans, like lobsters, scour the sea floor for leftovers." "With a busy time ahead, day fish try to sleep despite all the activity." "Some drifting like ghosts in the dark." "The anemone fish are also trying to sleep, but aren't finding it easy." "Their fiat-mates, the dotted crabs, are enjoying a midnight snack." "Some of the most active night prowlers are shells." "Many of us only know them from shell shops or dead on the beach." "But shells alive are much more precious - gypsy caravans, varnished by the oceans, constantly on the move." "Darkness also suits courting mandarin fish." "They have an unusually high sex drive and can spawn every night if the urge takes them." "Although our underwater lights give us a glimpse, we still know very little about what happens on a reef at night." "And our unwarranted fears have made it harder to learn." "Our attitude to the sea has been full of contradiction." "On the one hand we've revered it, on the other we've seen it as an enemy - dark and unfathomable, full of dragons and monsters." "These monsters of the deep have long been proven figments of our collective imagination." "But some believe they still exist in the form of sharks." "How wrong they are." "These magnificent creatures predate dinosaurs." "Like coral, they've survived several mass extinctions and have played an equally vital role in shaping ocean evolution." "Sharks have been roaming our seas for over 400 million years." "Fossil records show that thousands of species have come and gone, of which 370 are with us today." "They can be found worldwide, with many dependent on coral reef ecosystems for protection and food." "As top predators, sharks have influenced adaptation and evolution all the way down the food chain." "But contrary to popular myth, sharks are not just instinctive eating machines." "Many species exhibit powerful problem-solving skills and their brain-to-body-mass ratio is similar to many mammals and other higher order vertebrates." "So they are as intelligent, curious and social as some of our more favored animals." "They not only possess the 5 senses we do - sight, hearing, touch, smell and taste - but can also perceive electrical currents and magnetic fields." "If we're in the water with them, they can detect our presence from miles away." "They can monitor the beating of our heart ... .. and read our mood." "When it comes to humans, they are normally cautious creatures." "Whenever possible, they avoid us." "With good reason." "Every year, over I 00 million sharks are killed, the majority just for their fins." "Their fins are a traditional ingredient in Asian soup and their value rivals caviar." "The sharks are often finned alive and thrown back into the water to drown." "One third of all open-ocean shark species are now facing extinction, primarily due to over-fishing." "So if there is a killing machine in our seas, it's not them, it's us." "No shark is safe, not even the biggest of them all, the whale shark." "Up to 15 meters long and 12 tons in weight, they're an impressive sight." "But they're strictly filter feeders and dine mostly on plankton." "Unbelievably, they are also victims of illegal fishing." "Whale sharks are not actually whales but sharks." "True whales that visit the reefs include these, the minke." "Incredibly, these graceful animals are still being harpooned." "What trust they show us, regardless." "Before we began to plunder the seas, this is what they were like." "Linking the abyss with the surface, layer upon layer of shimmering silver." "A big school of fish is a defining image of a healthy sea." "It's a show of strength and incredible physiological adaptation." "Running head to tail in most fish is a row of sea les known as the lateral line." "Connected to nerves in the brain, this line consists of specialized cells that are sensitive to water displacement and movement." "Meanwhile, fishes' eyes are located on the sides of their heads to make it easy to see where they are in relation to one another." "So, vision helps maintain angle and distance between fish, while the lateral line dictates speed and direction of the entire school." "In this way, many fish can move as one and choreograph their own aquatic ballet." "Many fish school as juveniles and around half of all fish species form aggregations at some point in their lifecycle." "Even fish that prefer their solitude join a school from time to time." "Barracuda hunt on their own at night but hang out in packs during the day for protection and company." "With their pointed heads and streamlined bodies - up to 2 meters long they fly in unison through the blue like polished arrows." "Schooling makes it hard for a predator to focus on one target and is a great defense mechanism." "It's also a force to be reckoned with when it comes to feeding." "Few plankton in the area will escape this sweep of open mouths, as these rare filter-feeding mackerel make their coordinated attack." "Over the eons, the art of schooling has helped fish in many ways." "But now, ironically, it contributes to their downfall." "Just one net can collect a ton of fish at once." "And over I 00 million tons of fish are hauled from the oceans each year." "For the few big schools left, it must feel quite eerie moving through so much empty liquid blue." "These days, one of the only safe places for schooling fish is a marine sanctuary." "Whenever sanctuaries have been established and policed, fish stocks have slowly increased, helping to restore biodiversity." "A successful sanctuary becomes a precious time capsule ... .. a reminder of how rich the seas once were." "And could be again." "Unlike a ZOO, a marine sanctuary has no walls." "So it has the capacity to not only replenish the immediate area, but the oceans around it." "Because we have individual names for our oceans and have territorial borders, we forget that there's only one system." "There is only one sea." "Water, covering 70% of our planet's surface, connects us all." "What occurs even in our polar regions will eventually affect coral." "And, conversely, each new marine sanctuary is another powerful step towards saving our seas." "And when you consider that the global ocean makes up 99% of the living biosphere of the planet, every step counts." "Bee a use reefs are such important breeding grounds for so many marine creatures, this is where a new future might lie." "Renewal here is a daily affair and brings with it magical transformation." "Here, a coral cod blushes a different color when wooed by its mate." "A thriving reef is an aquatic rainbow." "And like the skin of the coral cod, these colors have meaning and function." "Silver scales reflect light and allow fish to blend into their watery backgrounds." "Bold, strong colors allow fish to recognize their own species in a crowd." "Color also indicates whether a fish is a juvenile or adult, and some fish change color quite radically as they mature." "Once fish are paired up, they can then use body posturing and color displays to communicate their intentions." "A male parrotfish erects his dorsal fin to intimidate other males and impress a nearby female who happens to look completely different." "And all across the reef, fish are on the lookout for a chance to mate and pass on their precious genes." "Most sea creatures have short intense lives compared to ours." "For some fish, a few years constitutes an entire lifetime." "So every good day on a reef is truly great." "A good decade is even greater, the chance for countless marine creatures to live their lives to the fullest and give rise to new generations." "In the quest to survive in these tropical seas, animals have had to be highly inventive and sometimes nature's own rules are broken." "Consider the seahorse." "These mystical creatures come in all sizes." "Some bigger than your palm, others as small as your fingernail." "The daintiest of them all is the pygmy seahorse, whose life is completely bound to gorgonian coral." "The extended seahorse family consists of 320 species, and includes pipefishes, pipehorses and sea dragons." "In most species of pipefish and seahorse, it's the male that broods the young." "It's not just this unusual parenting that sets them apart." "They have equine heads, prehensile tails ..." ".. and bony body plates instead of scales." "Despite their dragon appearance, many fish like to eat them." "So not being noticed has become their speciality." "Ghost pipefish are expert mimics of other animals and plants, including crinoids and coral." "Their predators find it hard to see them and so does their prey." "They spend most of their lives upside down, focused intently on the sandy bottom, searching for the tiny crustaceans that are their principal food." "So specific is their camouftage that pipefish rarely wander far from a particular habitat and perfect their mimicry down to the finest detail." "Other species conceal their true identity by moving like eddies and currents." "While some pretend to be sand-encrusted sticks or fallen leaves ..." ".. or pieces of algae." "If you know how to look, the masters of disguise are everywhere." "In this underwater Garden of Eden, even the snake turns out to be a fish." "Down on the seabed, deception is commonplace." "Individual reefs are often connected by areas of sand and rubble, and this is where the so-called 'bottom dwellers' dwell." "The most numerous of these are the gobies." "There are over 2,000 species of goby, making them one of the largest fish families." "Few of them grow bigger than your finger, which makes them a favored food for many large predatory fish ." "So they're always on the lookout and never far from the seabed." "They spend most of their days feeding, filtering sand through their gills to extract tiny food particles." "Sand is everything to the goby." "Sand puts food in their belly and also a roof above their heads." "Many gobies build burrows." "Its tiring excavation work, and partners sometimes don't agree on whose turn it is." "If the domestic argument can't be worked out, then this species, camouflaged as big eyes, can always go for a stroll to smooth things over." "Some clever gobies have enlisted the services of a slave." "In a most extraordinary partnership, gobies and blind shrimp live together, bonded by mutual need." "The shrimps excavate a burrow in which the gobies can hide, and they eat the goby's scraps." "The gobies act as sentinels, warning the shrimps of approaching danger." "The fish and crustacea have such a close working relationship that they're always connected, by tail or fin or feeler." "For fish close to the bottom of the food chain, a safe home base is essential." "Space is limited and good real estate hard to come by." "Trespassing isn't tolerated." "Territorial disputes are normally quick to work out." "But not always." "There's definitely no point picking a fight with this mighty armored beast." "It's the crown-of-thorns starfish, corals' mortal enemy." "By disgorging their stomachs and drenching polyps with acid, they eat living coral and suck the life out of a reef." "The starfish play an important role, clearing space and fostering biodiversity." "And few have stood in their way." "The starfish have always been a natural part of the cycle." "But now the cycle is unnatural." "Agricultural pollution has increased nutrients in the water, which in turn causes algal blooms." "Starfish juveniles are feasting on this algae and many more are surviving into adulthood." "Plagues of crown-of-thorns starfish are now regularly experienced on reefs worldwide." "But not all infestations are bad news." "A perfect example is the unlikely alliance between the eared sponge and the pink sea cucumber." "This sponge is highly toxic to most." "But the sea cucumber has adapted to live here in huge numbers, rising off the edges to spawn." "This is an inhospitable habitat where creatures are thriving." "Perhaps it offers hope for life in our changing seas." "It's certainly proof that anything is possible." "The oceanic world is ever changing ." "Nothing stays the same here for more than a moment." "Over the ages, corals have come and gone." "Today, they are disappearing again." "But what sets this cycle apart from any other in geological history is the presence of us." "For the first time in corals' existence, humans are having a direct impact on the ocean's chemistry and corals' destiny." "Many scientists believe we are heading towards our next mass extinction and that humans are the cause." "Reef-building corals are now seriously endangered." "And as reefs disappear, hundreds of thousands of dependent creatures disappear with them." "Furthermore, the demise of coral reefs is a clear indicator that our ocean is dying, and our ocean is our planet's life-support system." "The only way to save our ocean is to radically curb our C02 emissions within the next one or two decades." "We have all the tools to do it." "And if we succeed, we will not only save our reefs, we will ultimately save ourselves." "The future of coral, and how this story ends, is up to us."