Asia has the longest coastline of any continent, and the richest coral reefs on Earth. Its seas are connected by some of the world鈥檚 most powerful currents and are home to over sixty percent of all marine species. Asia鈥檚 oceans truly are home to a world of wonder offering spectacles not found anywhere else on Earth.
In the Western Pacific, huge numbers of stunning reef fish 鈥� Moorish idols 鈥� gather to spawn in the open ocean. They attract colossal numbers of grey reef sharks, which relentlessly pursue them, picking them off in a remarkable spectacle that鈥檚 revealed for the first time. Eventually, only a handful of the strongest Moorish idols remain.
From the Pacific one of the world鈥檚 most powerful currents flows west: the Indonesian Throughflow; where it鈥檚 squeezed between islands, terrifying whirlpools form. Off Komodo Island, the current provides food for manta rays, which effortlessly navigate the turbulent waters, feeding on plankton.
As the Throughflow continues, one branch flows to Western Java, past mangrove forests, which are home to the dusky-gilled mudskipper: a fish that lives its life on land, and can even climb trees. The males must build mud burrows, and they engage in fierce fights in order to win a mate.
Next, the current sweeps across the vast Indian Ocean, carrying objects that become play-things for giants 鈥� a mangrove seed is used by a juvenile sperm whale for a super-sized game of 鈥榗atch鈥�. The calf has a lot to learn, from sleeping upright to maintaining its buoyancy. Luckily, adults are on hand to correct its mistakes.
At the western edge of Asia is the Mediterranean Sea. Here, the shallows near a power station are a haven for endangered dusky sharks, and up to a hundred pregnant females come here in winter. The warm water discharged from the power station speeds up the development of their unborn young.
On the other side of Asia, deliberate steps are being taken to protect marine life: on Tyuleniy Island, in far eastern Russia, hunting restrictions have resulted in a boom for northern fur seals. On the crowded beaches, pups must move fast to avoid being crushed by battling males, and in the ocean, adults are prone to attack from orcas.
To the south, lies the Sea of Japan, where firefly squid embark on a one-way trip out of the deep ocean, never to return. They live for just twelve months, and after rising to spawn in the shallows, their glowing bodies wash up on the shore in a sombre spectacle.
Finally, we return to the Western Pacific, and the coral triangle 鈥� the richest concentration of marine life on the planet. The sea bunny looks like a cute cartoon character, but in reality, it鈥檚 a tiny blind sea slug, with no protective shell. Yet as we follow the bunny, no predators touch it. Finally 鈥� we discover why: its favourite food is a deadly-poisonous blue sponge; it is immune to the poison, and by eating the sponge, it becomes toxic to predators.
Life for the coral triangle鈥檚 predators can require surprising strategies. Black-banded sea kraits are marine snakes, and remarkably they team up with bluefin trevally fish. Huge armies of snakes and fish patrol the reef, hunting cooperatively to drive small fish out of their hiding places.
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Filming locations and species
- David Attenborough鈥檚 introduction: Natural History Museum, London
- Moorish idol and Grey reef shark: Philippine Sea, Western Pacific
- Reef manta ray: Komodo National Park
- Dusky gilled mudskipper: Ujung Kulon National Park, Indonesia
- Sperm whale: Western Indian Ocean
- Dusky shark: Hadera, Israel, Mediterranean Sea
- Northern fur seal: Tyuleniy Island, Sea of Okhotsk, Russia
- Barrel amphipod: Philippine Sea, Western Pacific
- Firefly squid: Toyama Bay, Japan
- Sea bunny: Mabini, Philippines, Coral Triangle
- Black banded sea krait and Bluefin trevally: Banda Sea, Indonesia
Interesting facts
- Asia鈥檚 21 seas stretch from Arabia, through the Indian Ocean and Southeast Asia, to the edge of the Pacific. Asia鈥檚 coastline is over 100,000 miles long.
- The Coral Triangle is a biodiversity hotspot and over 75% of the world鈥檚 coral species are found here.
- Southeast Asia contains a third of the world鈥檚 precious mangrove forests.
- The Indonesian Throughflow is the main pathway for the exchange of water, heat and salt between the Pacific and Indian Oceans.
- A special set of grasping belly fins enable mudskipper fish to climb trees, and their tails help them to leap and bounce across the surface of the water.
- Sperm whales can dive to depths of over 10,000 ft (3,048 m) for over an hour. The longest recorded dive by a sperm whale was nearly two hours long.
- The 鈥渇ur鈥� of the sea bunny is actually a series of tubercles that allow them to sense of their environment - especially useful as they don鈥檛 have eyes.
- Sea krait venom is one of the most lethal and potent venoms known. Roughly ten times stronger than a cobra and 100 times stronger than a rattlesnake, one bite can result in respiratory paralysis in just 12 minutes.
Filming feats
- The extraordinary behaviour of the Moorish Idols being chased by grey reef sharks was captured using a range of highly specialised cameras, including one developed specifically for this type of event that can be anchored to the side of a moving vessel and controlled from the deck, rather than having to be in the water, allowing an insight into the behaviour of the fish not possible any other way.
- The team achieved a ground-breaking feat by filming inside the intense whirlpools of Komodo National Park, capturing unprecedented footage for the sequence on the Indonesian Throughflow.
- The team captured a filming first for a natural history series showcasing a unique and accidental sanctuary for Dusky Sharks at an Israeli power station on the Mediterranean鈥檚 westernmost coastline.
Behind the scenes technology
- To film the intense whirlpools of Komodo National Park, the team used a specially constructed floating camera rig, operated by cinematographer David Reichert, who was dressed in multiple life jackets, as well as additional safety equipment and a support team nearby with throw-ropes in case of need. The team also operated a pole-cam from the main vessel to capture additional shots. These innovative approaches provided a unique perspective and also resulted in split-shots showing these whirlpools in action, offering viewers a rare and thrilling glimpse into these dynamic underwater phenomena.
- Filming the sea bunny in the Coral Triangle presented a fascinating challenge and opportunity for the film crew. To capture the intimate details of the sea bunny and its surroundings in the wild, the crew utilized several specialized pieces of equipment. Motorized underwater sliders allowed for smooth, controlled camera movements underwater, essential for following the slow-moving sea bunny in a cinematic manner. The use of 鈥榪uad pods鈥�, specialised four-legged underwater tripods, also helped provide stable platforms for the camera crew, ensuring steady shots in the often-unpredictable underwater currents. High-end probe lenses were also used for capturing the macro footage, which is an essential tool in obtaining close-up shots of the likes of the sea bunny 鈥� revealing its intricate features, offering an unprecedented look at the sea bunny鈥檚 鈥榚ars鈥�, which are chemical sensors.
Q&A with Mark Wheeler (Producer of Beneath the Waves)
What was the most difficult sequence to capture?
The sharks hunting the Moorish idols. It's never been filmed before. During our research phase we discovered that Planet Earth III had tried to film the event and not managed it. So yes, the odds were stacked against us. The timing of the event is critical. It only happens once a year, and no one really knows what the exact triggers for it are.
But in the run up to it you have these incredible few days where the numbers of sharks just build and build off the edge of the reef, and the numbers of the Moorish idols, which are the little reef fish that are waiting to spawn, build and build as well. And there's this kind of cat and mouse game going on as both drift up and down the reef.
How did you actually film it?
It was incredibly complex. As filmmakers, you need to cover it from every angle. To follow the main chase, you have to have drones in the air, so you can get that aerial view. You've also got to have multiple boats in the water because when it does kick off, a lot of the action happens at the surface. We had a specially rigged 鈥減ole-cam鈥� camera system, which was attached to the side of the boat to actually capture the running event.
Did you use divers as well?
Yes. You've got to have divers in the water waiting for it to happen, spending as much time underwater as they possibly can. But as soon as the chase starts, you haul them out of the water very quickly. There is no way you could film it as a diver. One reason is that the event is running at about 4 or 5 knots, which is far too fast for even an Olympic swimmer, let alone a diver with a great big underwater camera in front of him. The other reason is obviously the sharks.
There were 200 or more grey reef sharks, and they were hitting everything, even the side of the boat. If anything got in their way, they would try and take a chunk out of it. It's an impossible thing to cover from a dive perspective. So you need to put your eggs in lots of different baskets and film it in as many ways as you can.
How did you marry your different filming devices?
The game really is combining aerial drone shots with footage from the boat. We always had a drone in the air. We would bring one in to change the battery, and in the time we were doing that, we sent another one up, so we kept swapping them out. Not only were the drones filming, but they were giving us really accurate locations as well. If the boat drifts off, or the Moorish idols leave the side of the boat and you can't see them very well, then you just go to the drone find out where they are.
The boat had a top deck, and the action at the surface to start with was so profuse 鈥� you had splashing and sharks leaping out the water 鈥� that it was quite easy to spot and follow them. It's when the numbers of the Moorish idols dwindle significantly that you really need the drones to stick on top of them so that you don't lose them.
What were the biggest challenges of the shoot?
The sharks kept changing direction. They often came straight at the boat. A number of times the Moorish idols used the shadow of the hull of the boat as shelter, so all the sharks would then pile into the side of the boat. We'd have to turn all the engines off and sit there until the idols went again.
What other highlights are there in this episode?
Another favourite sequence involved one of the smallest characters, which was the mudskipper. We filmed it in this amazing mangrove forest in Western Java, in Indonesia. I spent a very long time looking for a location where we could film mudskippers, which was ironically not in the mud. You always see mudskippers in the mud, but actually they also live on sand. They live on tree roots. They live all over the place.
So the big challenge there was finding a location where you could film them with an interesting backdrops. Finally, I found them interacting on sand in this one incredible mangrove forest. It was a heck of a location, but it was very challenging. Using cameras with big lenses for tiny subjects was very hard. It鈥檚 really difficult to get those down to eye level with the mudskippers. But it was great. The mudskipper was a super little character and made a great story in the end.
Were there other obstacles to filming?
Yes. The biggest problem was we couldn't go in the water very much to shoot them. We had to do almost everything on land. We only went briefly into the shallows to film them in the water because every single day coming in and out of location on the boats we saw lots of saltwater crocodiles. There were groups of them everywhere, so we found moving around in the water very, very difficult.
Can you elaborate on the threat that the crocodiles posed?
It never leaves the back of your mind if you're walking through the water, and you've just seen a saltwater crocodile. When we knew there was one around in the bay, we were very, very cautious. We were working with the rangers from the national park, and we normally had one of them just keeping an eye on the crocodiles. If one disappeared underwater or it went somewhere uncertain, then we'd make sure everybody was away from the edge.
Everyone pulled back, and we did something else for a little while till we knew where it was. The other issue is that a lot of mangrove water is not clear. You have to be very wary when you鈥檙e moving the camera around in the shallows. Even when you鈥檙e just walking along the edges, you've always got half an eye on the water. The crocodiles are extremely fast on land. They will take deer and animals like that from the water side. But the crocodiles we saw were in the bay a bit more. We never saw any come into the mangroves, thankfully. That would have been a real red flag. But yes, it was quite hairy.
Finally, returning to the incredible sequence of the grey reef sharks hunting the Moorish idols, how do you reflect on that now?
Going for that sequence at all was a really big punt. But on a mega-landmark series, you need to be very ambitious. It's a pretty nerve-wracking process doing that. But you have an enormous sense of relief when it turns out well. You get a huge glow of pride that you actually did it. The team pulled it off. Everybody did such a good job that it was an incredible success. It鈥檚 now the opening sequence of the whole series. In years to come, when I look back over my career, that's something that's going to go down as one of the really big moments.