"Warm sunshine, and crystal clear waters." "It's a Caribbean cocktail that lures 1000s of visitors every year." "And these warm waters are also ideal conditions" "For one of the planet's richest habitats:" "The coral reefs." "But this beautiful world is fraught with danger too." "Thousands of ships have found it on the Caribbean's reefs." "Today, the pirates and their gold doubloons are gone." "But there is still treasure to be found here, the living treasure of the Caribbean's reefs and wrecks." "Dotted throughout the Caribbean are more than 7000 islands, with pristine beaches ringed by coral reefs." "Many of these islands form a long chain that creates a breakwater between the rough Atlantic oceans in the east and the warm sheltered waters of the Caribbean Sea." "Many of the reefs found here run parallel to the island shores." "They help protect the coastline from the constant pounding of the waves." "And they also support a huge variety of life." "Many of these fish and corals live nowhere else." "The driving force behind this whole community is the coral reef." "Fish like the Blue Tangs feed on algae growing on the reef, which helps to keep the coral healthy too." "Other fish come here to be cleaned at special cleaning stations up and down the reef." "Fish like Creole Wrasse drop in to be pampered top to tail." "It keeps them healthy, while the pay-off for their small attendance is a feed." "This grooming is a win-win situation, but it does require a gentle touch." "Shrimp tackle even the most sensitive parts." "They delicately hover up tidbits from in between a Red Hind's gills." "And even give the fish a floss." "Others use the reef for cover." "Caribbean reef squid are remarkable quick change artistes." "They take on the colours... shapes... and patterns of the reef, to hoodwink predators." "Once danger has passed, they switch colours again." "But this time to communicate with other squid." "A courting male flashes bright white one side, to ward off rivals, but he shows his mate, his darker, wild side." "[musical intermezzo] ~And when we started dancing...~" "The female seems to like his true colours and finally accepts his gift of sperm." "But there'd be none of this hustle and bustle, without the reef itself." "And many of the reefs would not exist without the islands." "From a few meters... to more than 100 miles across, thousands of Caribbean islands on the shallow waters where the shoreline meets the sea." "The ideal starting point for reefs to grow." "Although they look like underwater gardens, reefs are built by billions and billions of tiny animals." "These animals are coral polyps." "and they live together in huge colonies creating the intricate structures on the reef." "It's the soft corals that resemble the plants, swaying in the current like in a gentle breeze." "But the true reef builders and the bedrock of this whole environment, are hard corals." "like this brain coral, which may cross almost 2 meters across." "Hard corals have a tough external skeleton and over time they form the backbone of the reef on which the rest of the community can grow." "All this construction work is fueled by the clear Caribbean water... and tropical sun." "Plenty of light can reach the corals, which is vital, because living inside corals are tiny plants;" "Algae." "Which help make their food." "Algae convert the sunlight into nutrients," "Which the corals use to build the reef." "Hard corals get up to 90% of their food this way." "But although they depend on daylight, it's at night that corals really come to life." "It's now the coral polyps venture out of their protective shells." "And turn into tiny predators." "Their waving tentacles, covered in stinging cells, trap plankton drifting by." "One of the Caribbean's smartest hunters skulks the reef at night." "The many colours of the Caribbean Octopus give him perfect camouflage." "If you are a fish though, any colour spells danger." "If eight arms don't already give the Octopus the upper hand, he's got another trick up his multi-coloured sleeve." "It's known as "tent feeding"." "He simply sits tight, and spreads out his webbed arms." "So any fish hiding among the coral heads will find their getaway... blocked." "Thanks to this choice of tactics, it won't be long before the crafty Octopus takes someone by surprise." "They will feed on almost anything." "shrimps... crabs... fish... even other Octopus." "Most of the Caribbean's coral reefs encircle islands." "And they are just a stone's throw from the shore." "But other reefs are found right out at sea." "The Spanish used to call this area of shallow sea the "Baja Mar", or low sea." "Now it's part of the Bahamas." "These warm shallows and sandbanks run for miles." "And even out here, far from any island," "The water is dotted with coral heads." "These isolated outcrops are known locally as bommies" "In some parts of the Caribbean, these bommies conceal hidden treasures." "80 miles north of the Dominican Republic, lies an area of shallow coral sea called Silverbanks." "The name comes from a hoard of silver treasure lost here in the 1600's when a Spanish galleon sank." "Today these shallow waters still conceal huge treasures, but of a very different kind." "Each year between December and April, around 3000 Humpback Whales pass through the Silver Banks." "The water resonates with their song." "Only the males perform." "Each song lasts up to half an hour and can be heard more than 20 miles away." "The songs change gradually from year to year and even seem to have a local dialect, but no one is sure exactly what they mean." "They may be serenades to lure a mate." "A passing female..." "lingers." "Has this male hit the right note?" "As the two draw closer, she begins to flirt with him in what is sometimes known as a valentines dance." "One of the most acrobatic of all whales, this courtship display with its delicate body contact shows the whale's more gentle side." "[piano instrumental with "no woman no cry" theme]" "This love song certainly seems to be working it's magic." "[instrumental continues]" "Much of the humpback's behavior is still a mystery." "And their love lives remain very much a private affair." "Not every female though is here to find a mate." "The Silverbanks provide a giant birthing pool" "These calm warm shallows are the perfect place for a young whale to learn to swim" "Four metres long at birth, and weighing well over a ton, the calf's bond with its mother is incredibly strong." "The two stick close together, as the mother teaches her baby to swim and dive, constantly reassuring it with gentle nudges and caresses." "Here, in the comfort of this coral safe haven, the mother and calf establish their close relationship which will last up to a year." "By march the whales will have moved on." "Back to their feeding grounds of the cold Atlantic." "But this calf will return to these protected waters for many years to come." "Not all reefs are a safe haven though." "Over the centuries they've sent thousands of ships and sailors to a watery grave." "One notorious island reef has claimed more than 300 wrecks." "But of the many shipwrecks in the Caribbean, one tragic history stands out from all the rest." "The Rhone." "A 90 metre Royal Mail steamer lies off Black Rock Point, in the British virgin Islands." "In 1867, this ship was blown on to the reef by one of the last hurricanes of the year." "With a terrible loss of life." "At the height of the storm, the captain ordered the passengers to be strapped to their bunks for their own safety." "Shortly afterwards he himself was washed overboard and never seen again." "Pushed by strong winds and high seas, the Rhone was driven onto the reef." "Seawater flooded the engine room, the boilers burst and she went to the bottom in seconds." "Out of 147 passengers and crew, just 23 survived." "Now a lone Barracuda patrols the decks." "and the Rhone itself has a whole new lease of life." "Fish are the first to claim a shipwreck as their own." "The wreck offers shelter from the currents and a hideaway from predators out on the reef." "At first this iron hulk must seem a new and alien environment" "But given time, it starts to look a lot like home." "Although most corals are slow growing, eventually the skeleton becomes encrusted with a whole kaleidoscope of life." "Until after almost a century and a half it's hard to see where the Rhone ends and the reef begins." "Many fish feel so at home here, they stash their most treasured possessions on board." "These purple patches look like coral, but they are actually the eggs of Sergeant Major Fish." "After his mate has laid as many as 200,000 eggs," "It is the males job to guard the nest." "He clears away debris and wards off intruders until they hatch," "6 days after being fertilised." "As far as these fish and the other wildlife found here are concerned, a wreck makes as good a home as any reef." "Ships still fall foul of reefs and sink throughout the Caribbean." "But these wrecks make such great homes for marine life, you don't always wait for accidents to happen." "Hundreds of boats are now scuttled deliberately to form new artificial reefs." "Almost anything can turn up on the seafloor." "Even the odd airplane is laid to rest down here." "Whatever goods were once transported by these vessels are long gone." "Replaced with cargo... of another kind." "In this case:" "Nurse sharks fill the hold." "They spend most of the day piled up in sluggish groups" "Unlike most sharks, they don't have to keep moving to breathe, they can pump water over their gills." "What look like fangs are fleshy sense organs called barbels, used to touch and taste." "And to find prey." "But other fish are safe during the day, the Nurse sharks only hunt at night." "The sharks have made every inch of this wreck their own." "These artificial reefs aren't just a popular hangout for wildlife though." "Tourists come to dive the wrecks, which helps to make the Caribbean one of the world's top holiday destinations." "More than 20 million people come to stay here every year." "And that is without the extra 10 million cruise ships bring in." "All wanting their little piece of paradise." "Many visitors don't make it further than the beach, but the more adventurous dip their toe in the underwater world." "A Stingray may look gentle and harmless, but it does have a sting in its tail." "Tourists would be wise to give Stingrays a wide earth." "So what's going on here?" "Each year thousands of people come to this sandbank off Grand Cayman island for a close encounter with the rays." "They bring the food, the rays put on a show." "It may look like a recipe for trouble, but the rays seem to enjoy the contact too." "Perhaps we make good scratching posts." "Stingrays are creatures of the shallows, but what makes the Caymans special is their depths." "Where the reef ends and the open sea begins." "Here the reef drops away to the seafloor hundreds of metres below." "These underwater cliffs are called the drop-off." "Near here, the Cayman trench plummets more than 4 and a half miles down." "It's the deepest known point in the Caribbean sea." "At the top of the drop-off, where there is still plenty of light, both hard and soft corals are found." "But as you descend into the abyss, things start to change." "Down here you enter a very different world." "The hard reef building corals, that need sunlight, struggle to survive." "By 30 metres down, they're all but gone." "In these dark waters all corals are carnivores." "They send out fragile mazy fingers to trap morsels falling from above." "It's not an easy living." "Some deep-sea corals grow just a few milimetres a year." "Some of these weird wonderful structures have found a surprising home more than 200 metres below the surface." "A cargo ship." "Since she sank in 1976, she has been wedged in place on a ledge sticking out from the drop-off wall." "Should this rock ever give way, she'll fall another half a kilometre down into the pitch dark depths." "For now though, she provides a ghostly sanctuary for colonies of deep sea life, rarely seen by human eyes." "Among the most bizarre creatures down here, are Stalked Crinoids or Sea Lilies." "They bear a crown of arms, covered with sticky tentacles, stretched out to grab up drifting particles of food." "As well as offering a home, the wreck itself provides a source of food." "These orange stalactites called rusticles are formed by millions of microorganisms slowly eating away at the ships steel." "A century from now, the whole ship will have been devoured." "Leaving only a pile of rust on the seafloor." "Wrecks may be among the deepest, most intriguing reefs, but the crown jewel of all the Caribbean's coral reefs, eclipses them all." "It runs for more than 180 miles offshore from the Central-American mainland." "From Belize and Mexico, right down to Honduras." "This huge barrier reef is the second largest coral structure anywhere on earth." "Only Australia's Great Barrier Reef is bigger." "This massive reef system has keys, shallows, batons and drop- offs." "And another claim to fame the Blue Hole." "A natural sinkhole 400 metres across." "Formed when the roof of a huge cave collapsed, it's more than a 120 metres deep." "Hence its colour and name." "But the dark waters of the blue hole are empty compared to the teeny reef nearby." "Providing so much food and shelter, coral reefs take up just 1% of seas worldwide." "yet they're home to more than a quarter of all species of marine fish." "A reef this size is a whole universe of its own." "And a large reef has some large inhabitants." "These barrel sponges up to 1 metre across, are among the planets simplest animals." "They have no nervous system and no real internal organs." "Rooted to the reef, they have no tentacles or arms to gather food." "But what they can do is pump water." "Up to 10,000 times their own volume every day." "For every ton of water strained, they'll filter out maybe 25 grams of food." "To help prevent themselves from being eaten many sponges are toxic." "But that doesn't stop them being a good hiding place for those who want to give predators the slip." "The Barrier reef is also a refuge for the Loggerhead Turtle named for its massive head." "This one probably hatched out somewhere along the Caribbean coast of Mexico." "and then spent years drifting around the open seas." "No one is sure exactly where they go." "Eventually though, Loggerheads return to the reef." "Less well traveled is the Manatee." "A relative of the elephant." "This reef off Central America is one of the Antillean Manatee's last strongholds." "One of the few places where they venture out from the protection of their coastal mangrove swamps." "In many ways these shy creatures are still a mystery." "Only males appear to cruise the reef and only in the summer months." "Why the females don't join them?" "No one knows." "These peaceful plant eaters seem perfectly in tune with the famously free and easy Caribbean life style." "Once the sun goes down though, it's a different story." "The reef is less laid back at night." "In the dark unwary fish are shadowed by hunters." "Among the biggest and flashiest of them all is the Silver King." "Also called Tarpon, they may cruise the reef up to 50 years." "And in that time grow two and a half metres long." "At night Silver King rule the reef snapping up smaller fish." "Caribbean nightlife is full of surprises." "When it comes to romance these Indigo Hamlets make most couples look a little dull." "They perform an elegant and complex courtship ritual." "In which the pairs swap sexual roles." "Each one has both male and female sex organs." "So they produce both eggs and sperm." "Courting Hamlets are a common sight along the Caribbean reefs." "But just a few nights every year" "The reef puts on an even more magical show." "The exact timing of this event is linked to the cycle of the moon and changes in the water temperature." "Every summer at around the same time the corals themselves begin to stir." "Eventually this builds into a mass synchronized spawning releasing a snowstorm of eggs and sperm." "When this mass of eggs and sperm combine, they form a baby coral or planula." "The Planula are carried on the ocean currents until they settle." "on part of the reef... a wreck... or even somewhere new... creating a brand new coral colony." "Here in the Caribbean coral spawning can occur at any time between July and September." "Between March and May, the full moon seems to help trigger yet another spectacular display." "Snapper are normally solitary fish, but now they gather in their hundreds from all corners of the reef." "They've come for the social event of the year." "One they can't afford to miss." "Gradually, the snapper throng moves up into more open water." "And then... at some invisible signal it begins." "A mating "free for all"" "releasing clouds of eggs and sperm." "But this extravaganza doesn't go unnoticed." "A Whale shark looms out of the depths." "The fish appear oblivious, but soon more party crashers arrive." "Reaching more than 15 metres long and weighing 30 tonnes these sharks have a titanic appetite to match." "And as many as 25 may turn up for the feast." "When the party is at full swing, the Whale Sharks make their move." "They are no threat to the adult Snapper though." "They are filter feeders after the fresh spawn." "The cloudy water passes through the spongy tissue on their huge gills." "and they start to gorge on millions and millions of eggs." "Gulping in huge volumes of water, each shark can filter over 6000 litres every hour." "Whale sharks are epic ocean voyagers." "They dive to a 1000 metres or more, and travel for 1000s of miles across the seas." "Females are rarely seen and little is known about their lives." "Eventually the party is over." "Stuffed to the gills, these gentle giants retreat to continue on their mysterious way." "The shores and islands that encircle the Caribbean sea, help create the perfect conditions for coral reefs to thrive." "From the isolated bommies of the sandbanks, to the crowded shallows." "The smallest desert island, to the huge barrier reef." "Each one of these coral hideaways harbours its own treasure" "A rich and glorious variety of life." "In the next program we see what happens when this beautiful paradise becomes a hurricane hell." "Winds of over 150 MPH destroy the forests." "Storm surges wash beaches away." "And coral reefs pounded to rubble by huge waves." "We discover how the wildlife of the Caribbean copes with nature's most deadly force." "Transcription and synchronization done by HIman."