Red sea wonders - Stunning coral reefs and rare marine life revealed

The Red Sea. A special idyll of the Orient. A place of silence, strength and diversity. The Red Sea is famous for its high salt content which especially contributes to clear water. Algae can't spread easily here. This is why its broad coral reefs can be considered a true paradise for divers. We can find lots of highlights of marine life here. There are a lot of colourful shoals of fish, popular anemone fish, basses, vigilant morays, odd puffer fish and of course elegant turtles. The biggest attraction is colourful coral reefs shining in the sunlight. From the Earth's orbit we can clearly spot the elongated form of the Red Sea. It is a narrow sea, 2,240 kilometres long up to 2,604 metres deep that borders the Indian Ocean and lies between North East Africa and the Arabian Peninsula. The Red Sea contains about 200,000 cubic kilometres of water. Its surface is spread over 438,000 square kilometres and the water is on average 538 metres deep. A good question would be why it is called the Red Sea? There have already been several interpretations for it since antiquity. On the one hand, blue algae grows in this stretch of water. It swims right under the surface of the water. In its flowering season it becomes red. This is why the water seems to be red if you look at it from above. But this plant isn't widespread. Another explanation for the name could be the red rocks at the Red Sea's coast. They are red because they contain ferric oxide which causes that shade. According to legend, those rocks have been burned red by the sun. The Red Sea could also have got its name from Iranian seafarers who used colours to name the four points of the compass. The colour of the south was red. The sea is geologically very young. It was created 25 million years ago because of the separation of the African and Asian continental plates. Then the crack was filled with seawater and the Red Sea was born. Because of the constant drift of those continental plates, the Red Sea widens out 1.2 centimetres on average per year. The south of the Red Sea is especially interesting for us. Over there where Eritrea, Djibouti and Yemen border the sea, right in the direction of the Indian Ocean. There is a narrow place in this area where the sea is only 29 kilometres wide and only 130 metres deep. Because of this natural bottleneck, there is only a sluggish water exchange which causes a high salt content. In these conditions, plankton and algae can't spread easily and the water seems to be crystal clear, as we can already observe from the shore here. But also under the water, the view is much better than elsewhere, as we are about to see now. The most widespread creature is as well the most important one. The coral. The fire corals and madriples, the stone corals, are the main constructors of the Red Sea's giant reef. For thousands of years, these animals have been forming enormous constructs right up to whole islands all over the world. The best known among them are the Bahamas, Bermuda and the Maldives. That is possible because corals which belong to the group of cnidarians perpetually excrete limestone. The zooxanthellae, a microorganism that lives inside the coral, helps the corals to form lime. They live in symbiosis, which means that they provide and care for each other. These corals are really sensitive to water temperature. It always has to be between 20 and 29 degrees centigrade. Therefore, they mostly live in shallow, tropical and lighted waters. Stone and fire corals are actually just giant colonies of polyps. Every polyp is only a few millimetres, up to one centimetre long. Besides the sustenance through their symbiotic partners, corals mainly feed on planktonic organisms which they catch with their tentacles. Fire corals got their name from their cnidocytes, or stinging cells, with which they can pierce through human skin and inject a painful poison. The symptoms are comparable to skin contact with a stinging nettle, but the pain can persist from two days up to two weeks. The injuries can even leave scars that can be visible for a lifetime. That's why divers should be really attentive and careful not to make the common mistake of confusing fire corals with seaweed. As for distribution between sessile animals, fire corals are really successful. When fighting for light and living space, fire corals can effectively overrun their rivals. These corals also have so-called defence polyps, somewhat bigger polyps than the usual ones, which they use in their fight for a spot on the reefs. They use them to sting their opponent's tissue and thus destroy it by poisoning it. But the fish that you can see here are not impressed by that. The anthinae, a special kind of bass. Actually, with them it's quite the contrary. Living in groups of thousands, they use the coral's complex formations to hide from their predators. What's interesting is that almost all of these fish are females. Usually only 1 50th of the group are male. At first, adult fish are always females that later turn into males. But that mostly just happens if a male fish dies. If that is the case, the strongest female of the group transforms into a male fish in just a couple of days to take its place. Another resident of the reef is the soft coral. Even though it is related to the stone and fire coral, it has a totally different structure. It gets its stability from inner water pressure. Its limbs and strains are not covered in polyps. Those are located at the ends of the arms. The soft coral's colours are usually brown, yellow or green. If it lives in the shadows, it has a bright red, orange or purple colour. Mostly they are located on the edges of reefs, overhangs or on the ceilings of caves. Corals are really important for a lot of fish. They provide shelter for small and normal-sized ones. That's why they're almost always surrounded by huge swarms. If there's an enemy, they can instantly hide between the branchy corals and are almost unreachable for big predators. The coral's ability to emit stinging poison is a huge advantage here too. Although the fish have to be careful not to come into contact with the defence polyps, because otherwise they themselves might be the victims. Because of natural barriers and because of the environment influencing those animals in a special way, many unique species which can't be found anywhere but the Red Sea have developed over millions of years. One of those creatures is the popular clownfish. This genus here is also known as the Red Sea anemonefish. They eat plankton and algae and are comparatively small. 15 centimetres is the maximum. The clownfish lives closely in a so-called symbiosis with anemones. That means, as we've just learned about the corals, the two different species both profit from living together. Surprisingly, clownfish are able to live with anemones although its nidoblasts are toxic. Why doesn't it disturb the clownfish? Very simple. It possesses a slime layer which protects it from the deadly poison. The anemonefish protects the anemone, driving out predators like, for example, butterflyfish. In return, the anemone protects the anemonefish from predators and those can even be rather funny-looking creatures like cornetfish. Some of them can become much bigger than a metre. Those sit-and-wait predators drift inconspicuously in the water to suddenly snatch smaller fish. This is why they're often pretty shy and take to their heels as soon as they spot a diver. Let's continue our way under the surface of the water in search of the most colourful fish of the coral reef. And here we see a royal angelfish. They grow a little bit longer than anemonefish, up to 60 centimetres. The blue-cheeked butterflyfish is one of the most eye-catching reef fish. They can differentiate their fellow species and other butterflyfish through their colouring. Most of the time they live in couples and sometimes in smaller groups too. A rather inconspicuous inhabitant of the Red Sea is the orbicular batfish. It's pretty flat and high, but the older it gets, the more it becomes discus-shaped. Characteristic for its shade are the vertical and brown bands. Thanks to this high contrast, some predators can't recognise the form of the fish easily and assume them to be leaves washing through the sea. Older fish seem to be more silver and grey, so that they look even more inconspicuous. In spite of their inconspicuous appearance, orbicular batfish are very active and curious. Divers often tell about orbicular batfish nibbling at diving equipment or grabbing for rising bubbles. Bannerfish get their name because of the large colour stripes on their flat bodies. Mostly the colours are black, white and yellow. The colours around his eye area are also really distinctive, comparable to a raccoon. Here we can see a yellow margin triggerfish. This species either lives alone or in a partnership. For their eggs, they build big hollows of sometimes up to two metres diameter, in which the female can lay up to 500,000 eggs. The bale of eggs, about the size of a fist, is weighed down by the parents using coral branches. And watched over by them until they hatch. There are a lot of different kinds of filefish. Optically, there are numerous variations in colours and patterns. But still, there are a lot of parallels regarding their body structure. Just like their relative, the triggerfish, they have strong teeth. And there are kinds that feed on corals too. This coral actually looks kind of gnawed off at some places. Maybe that was one of the many relatives of the orange filefish. Many inhabitants of the reef also feed on algae or other floating plants. If there's an opportunity like this one, there are a lot of kinds of silvery shining fishes. For example, the rabbitfish. The giant grouper is a true giant. Up to three metres long, he is the biggest bony fish in the coral reef. The young are black and white coloured and have yellowish fins. Whereas the adult fish are grey-brown with some brighter spots on them. Striking about them as well is their grim face, especially their mouth. The giant grouper's territory lays 50 to 100 metres underwater. Sometimes in caves or wrecks. They usually only leave it when searching for a partner or for hunting. They feed on critters, longoost and small sea turtles. And sometimes even small sharks. However, in heavily fished areas, there aren't many giant groupers anymore. This predatory fish can be really intimidating because of his size. And even though they don't look like it, because of their size and their very slow way of moving, they are really aggressive. Sometimes they even attack humans. 35 metres deep down, we can find the black triggerfish. This fish is the biggest of its kind and reaches up to 40 centimetres in length. The name of the triggerfish refers to a mechanism which protects it from being eaten by predators. It uses its strong fins to cling onto coral reef so that it can't be pulled out against its will. The great diversity of different kinds of fish is really impressive. Here under the sea, it is a true paradise for fish. But there are also a lot of things to discover above the water surface, even for humans. The long beaches, directly bordering on green bushes and forests, provide a great mix of the atmospheres of beaches and bathing lakes. The long sandy beaches along the shore invite you for relaxing walks in the salty, humid air. Not only divers enjoy the great bodies of water, it is inviting for everybody to either take part in some sporting activities or just to simply relax and enjoy it. If you are interested in sailing or water motorsport activities, you can discover all kinds of yachts, motorboats or jet skis. Even so, you should not deny the fact that the nature of the Red Sea suffers from human influences too. Especially polluting the water with dirty sewage or wild fishing really damage the ecosystem. Another harmful impact of tourism is wild anchoring. The anchors rip out parts of the coral reef and thus destroy it. Diving tourism has also taken on an overburdening dimension. However, initiatives for nature conservancy, protected areas and other restrictions have already made a significant difference. But people need to make more of an effort to live in communion with nature. Because some species of the Red Sea are already endangered. One of them, the beautiful sea turtle. One of the Red Sea's largest inhabitants is passing us right here, the sea turtle. Even though it is longer than 1.5 meters and weighs more than 200 kilograms, it manages to daintily float through the water. Here, it truly is in its element. The sea turtle seems to glide through the water like a bird glides in the air. Even though it can move on shore, it spends almost its entire life underwater. Sea turtles are not faithful to a habitat, meaning that they do not have one specific place to live. Every year, it travels enormous distances in the sea. When sea turtles are still young, they feed on crayfish, jellyfish and fish eggs. But when they get older, they become vegetarians. Sea turtles can live up to 50 years. As I said, the sea turtles are an endangered species. The main reason? In a lot of Asian countries, they are known to be a delicacy and their shells are often manufactured into jewelry and lucky charms. Since 1979, hunting and dealing with sea turtles has been illegal. But still, every year, thousands of them die because they are being hunted illegally or if they accidentally swim into the shrimp fishing nets. Among the sea turtle and the large variety of fish, the moray eel calls the Red Sea its home as well. They look really similar to eels. If you compare them to the snake eel, it is hard to see a difference. Both of them have long, stretched bodies that are flattened to the sides. The moray's colours are usually brown to black-purple. But species that are living in tropical regions are really colourful and noticeable. Unlike other fish, the moray does not have pelvic or pectoral fins, not even in the larva stage. They move by meandering. Due to the structure of its gills, the moray eel has to actively breathe underwater. For this process, it has to open its mouth, close it again, and then push out the collected water through its gills. This behaviour often gets misunderstood as a threatening gesture by inexperienced divers who may start panicking. Even though they might look scary, morays are calm animals. They sometimes even allow people to pet them. One still has to pay attention to not hold onto them or make them feel cornered. In that case, they may bite, which can cause a painful infection. In the worst-case scenario, it's even possible to lose a finger. Moray eels living in corals that attract a lot of tourists often get fed. This, however, affects their behaviour and only makes them more obtrusive and aggressive. The Red Sea, with its huge coral reef, offers a lot of great possible hideouts. Depending on the size of the moray eel, it can have several hideouts, up to 200 metres from one another. Smaller moray species rarely leave their shelter and only hunt in their own caves. To not cut themselves on the sharp edges of the corals, their skin is covered in a thick layer of mucus. Moray eels are very faithful to their home and only leave it to hunt and to reproduce. Something particularly interesting is the fact that the moray eel is nocturnal. This means the moray can cover itself in the darkness of the night. In addition to that, most of its prey is resting around this time. But do fish actually sleep? For us humans, it might be unimaginable, but most fish don't possess eyelids and therefore can't close their eyes. Nonetheless, they must rest at night to relax and restore their energy. Especially coral reefs, with their countless hideouts, are often used as a shelter where the fish can switch into a kind of standby mode, which lowers their awareness and reaction time. Here, we caught a nocturnal porcupinefish who was looking for a shady place he could rest during the day. It's really difficult to say how awake he must feel right now. Something we definitely know, however, is that fish never really fall into a state of deep sleep. They're always prepared to react in case of a sudden threat. That's also why this porcupinefish flees as soon as he notices us. Some species have developed different kinds of abilities to reduce the threat of potential predators. The porcupinefish is, just like the pufferfish, a slow swimmer. He therefore needs a different option to protect himself. Regarding protection, the pufferfish, as well as this white-spotted puffer, have a truly unique technique. They can inflate themselves like a water balloon, becoming so big that they don't even fit in the mouth of many predators. The blue-spotted ribbontail ray, who prefers hunting during the nighttime or high tide, covers himself with some sand if he wants to rest well-sheltered. When the sun starts setting over the Red Sea, the time for all nocturnal animals has come. That means their day begins when calm time starts for most other living beings. Slowly but surely, the sun disappears beyond the horizon and induces an idyllic atmosphere. Even from the orbit of our Earth, the region of the Red Sea looks simply magic. Beneath the water surface as well, we can experience a completely different world. The moray eel now starts its search for prey. Its big maw and sharp teeth give it a big advantage during the hunt, since it's easier to keep hold of its prey. If the victim is too big to be swallowed whole, the moray can form a knot around it with its body. By doing so, the moray can hold on tight to its meal while ripping it into small pieces with its mouth. Morays have a great sense of smell, which helps them to track down prey. They have four nostrils that are located over their mouth. These are the best features to help tell them apart from the similar-looking eels. All these abilities and traits make the moray a very effective hunter, and its menu is long. Because there is no such thing as a food specialist among them, morays actually eat pretty much everything that consists of meat, even rotting carcasses. But still, bigger morays are pretty modest about the search for food, and so only go hunting once every two or three nights. Other animals deal with the darkness in a totally different way. These triggerfish, for example, hide in caves and crevices at dusk. There, they can use their trigger mechanism to clip onto the underground and not drift in the water current. Sea turtles as well sometimes use the technique of wedging to get some rest somewhere without getting disturbed. This is mostly what they do when they feel molested by other big creatures, for example, pushy divers that swim after them for a long time, trying to film them. Well, at least the turtle's look tells us very clearly, and we obviously want to respect that. Sea turtles also do not have the special luxury of being able to rest in the dark. Especially for turtles living in open waters, the night is a peculiar matter. During the breeding season, they only swim by night and travel around 2,000 kilometres eastwards. They are heading to the beach of their birth, using the Earth's magnetic field to orientate. When they have reached that target, they dig a hole in which they lay their eggs, all in the darkness of the night. Optically, their eggs look really similar to birds' and chicken eggs. During breeding time, countless turtles lay their eggs on the same beach, where they can then be hatched by the sun. Interestingly, this is the point when the sex of the offspring is determined. If temperatures are lower than 29.9 degrees centigrade, it's male. If they're hotter, it is female. Because all the eggs have been laid at about the same time, there are a lot of baby turtles hatching at the end of the breeding season. This means that more of them have the chance to survive their difficult and exhausting first journey into the ocean. Because on their way there, they can get eaten by other animals. Seagulls especially, but also ravens and various land animals. For example, raccoons. The small and soft turtle babies are a tempting snack for those animals. But when all of them hatch at once, even hungry predators get replete quickly because obviously they can only eat what fits in their stomachs. In that way, these small sea turtles hopefully go successfully on their way and contribute to the raising of the sea turtle's decreasing population. When looking at the turtle swimming, we can truly only wish to have these glorious creatures on our planet forever. Back to the night in the Red Sea. The nocturnal predators are coming out. One of them is the blue-spotted ribbon-tailed ray. On the menu today, shellfish, crayfish and starfish. Rays feel very comfortable on the soft seafloor, 40 metres deep. Stingrays have the habit of burying themselves in the sand so they cannot be seen while they're waiting for prey. Sometimes they just do it to rest. The blue-spotted ribbon-tailed ray is easily distinguishable from other ray species by his colour and special blue dots. He can change their intensity if he wants to hide. Buried and with low colour intensity, he is almost impossible to spot. What's good for the stingray can easily ruin a nice vacation. The ray reacts within a split second with a sting using his venomous thorn. The poison is not deadly, but the thorn can injure internal organs. Visitors should be very careful in places with a high stingray population. Big relatives of the stingray behave a little bit differently. For example, the spotted eagle ray. He has more similarities with the good old manta ray. Both like to swim in deeper water, especially at night. During the day, they can be seen near the surface, also closer to the coast, mostly just to warm up. He has a blackish-dark blue colour with a white stain pattern on the top of his rhomboid body. His belly is white with some random dark stains. Measuring from tail to head, they can reach over 3.3 metres long and 3 metres wide. On their tail is a sting with barbs placed on it to defend themselves against enemies. Let's hope that he does not have to use it on his way down into the darker and deeper water. Also, we get to meet the porcupinefish again. Finally, he is moving. Now we can see his special way of swimming. He's not using his tail as a drive. He's using it for steering. For thrust, he's using his breast fins. To defend himself, Mother Nature gave him, besides little spikes on his body, a, for fish, deadly poison. Even humans who eat parts of the fish that have traces of poison are in danger of dying. Contact can lead to paralysis or even death. Good for the porcupinefish that we are not here to eat him. Let's leave him alone because the night is short. The calm night and beautiful silence is truly romantic. Even the moray eels realise and appreciate it. They go out at night to look for possible partners. The corals reproduce. Most soft corals are male or female, but a small number of them is hermaphrodite. Depending on the species, there are two different ways of reproduction. The first method is the ejaculation of the ova and sperms into the water, where they both meet. The chance for successful pollination is very low. That's why everything has to be perfectly timed and coordinated. In the case of success, the larvae then float in the water and drift away. If they land on free reefs or stones, they will transform to normal polyps and start spreading into a big colony. The second method is a little bit different. The coral only ejaculates the sperms, which float in the water until they hit the ova on other coral, which never left the coral. The fertilised ovum evolves into a ready polyp. It will not be repelled in the water until it is fully evolved. The time of day does not play a role for the coral. While the sun is rising, lots of inhabitants of the reef get into their regular day-to-day rhythm. The moray eel now has time to relax after filling his stomach and getting back to his home cave. Already waiting, a cleaner wrasse. The fish climbs in the eel's mouth and eats the remaining food off its teeth. It is an advantage for both. The moray eel has clean teeth and the cleaner wrasse is fed. Most fish that live in this reef are getting really active now. In this environment, as a fish, you have a strategic advantage if you stay in groups or swarms. Not only birds live in big groups, fish do it as well. But not every swarm stays the whole year. Some fish only group up for a couple of months, some only if the situation requires it. Swarms can be separated into two different types, the proper and the irregular. The jack mackerel, butterfly fish and the big eyes belong to the proper type. The pure swarm includes mostly fish of the same species and age and always has the same number of members. If one member is left alone, they seem stressed, confused and disorientated. Quite the contrary if they are in the company of the rest of the group. Everything is well coordinated. They stay organized due to communication between each other. That's why the distance between the fish and the speed always stays the same. Proper swarms can be found in salty waters. They live under the constant pressure of predators. The coloring is perfectly adapted to the swarm life and a big advantage for the fish. It's supposed to confuse enemies. Besides the proper swarm, there is also the irregular swarm which has several similarities to the first type. They are also known as group fish because of their habit of only gathering if predators are nearby. Fish of various different species and age can be found in such a swarm. Even if the fish are left alone, they can get along as well as they did in the group. Irregular swarms live mostly in freshwater. Swimming in groups or swarms holds the advantage that it is more likely to survive an attack by a predator. It is much harder for one fish alone to escape the enemy because for predators, focusing on only one is easier than on all of them at once. In addition, the high number of members in the swarm helps spot offenders faster. But ironically, this vast amount of fish also attracts enemies and predators. Swarm formation is actually only profitable when the habitat is large, food portions are widely spread and big enough to provide for the whole group. But swarms are useful for hunting though. When using techniques like encircling or pushing, prey can be caught much more easily and faster. For us as observers, these totally mixed swarms obviously provide one kind of selfish advantage. They are just incredibly beautiful to look at. It is amazing how many abilities and strategies you can find in the reef's creatures that are all sharing one habitat but are using it in totally different ways. Through diversity, a giant kind of organism is created. In which the smallest component adds its part to the puzzle, which is even more than just the sum of its component parts. Our trip through the reef is over now. But the Red Sea is always worth a visit. In the variety of its inhabitants, there's always something new to discover. On that note, goodbye and see you.