CHRISTOPHER STEVENS explores how Blue Planet II was made

Shot in lustrous colours that hypnotise us with their unworldly glow, Sir David Attenborough’s latest masterpiece, Blue Planet II, was four years in the making and is being hailed as one of the greatest natural history series ever.

Technological advances have allowed the camera crews to record things never before seen on screen. As Sir David says: ‘Underwater films have changed a great deal in 60 years. Cameras have become smaller and smaller. They can record hours of material before they need reloading.

‘They are so sensitive that they can record pictures in depths far beyond the reach of the sun’s rays. In short, there is virtually no part of the seas we cannot explore.’

Between land and sea: A split-screen view of the life above and below the surface

Behind every scene, watched by 10 million viewers, was the dedication and courage of a talented team of camera operators, wildlife experts and producers — all committed to bringing the wonders of the deep into our living rooms.

Here, revealed by the camera crews themselves, are some of the strangest and most remarkable tales behind the wildlife documentary that is entrancing the nation.

Watch out for the wily octopus

Sometimes, a naturalist will befriend an animal . . . even under the sea. Marine scientist turned Blue Planet cameraman Craig Foster struck up a relationship with a common octopus in the South African kelp forests where he has dived every day for many years.

All octopuses have individual personalities and are capable of recognising humans and even telling them apart, Craig says. One seemed to enjoy his company and for months allowed him to follow her on hunting expeditions.

But when he started filming, disaster struck — his octopus friend was seized by a pyjama shark, a striped (hence the name) 2 ft predator that lurks in shallow waters around the South African coast. Horrified, Craig thought he was about to witness his star performer being eaten.

Hidden depths: A sea toad walks across the ocean bed on Blue Planet

Hidden depths: A sea toad walks across the ocean bed on Blue Planet

But the octopus was a wily fighter. She inserted two tentacles deep into the shark’s gills, preventing it from breathing. To avoid being suffocated, the fish had to let go of its prey.

Craig’s octopus had another trick up one of her eight sleeves. She would gather empty shells around her while hunting in the open, away from her lair. If she saw a shark, she curled up in a ball and drew the shells around her like armour.

Both these behaviours are new to TV — and we can see them only because of the incredible patience of film-makers like Craig, who let their subjects learn to trust them.

Tiny fish that’s camera shy

Percy the tusk fish may be clever, but he is no attention seeker. This little inhabitant of Australia’s Great Barrier Reef has learned how to smash clams open by holding them in his mouth and whacking them against a piece of coral he uses like an anvil.

When underwater cameraman Roger Munns dived to observe and capture this behaviour, he found Percy was shy.

The tiny fish didn’t like to be watched while he prepared his dinner, especially by a creature as large and scary as Roger. The cameraman had to remain in position for hours to gain Percy’s trust.

A diver uses an underwater sound detector for locating aquatic creatures in the deep

A diver uses an underwater sound detector for locating aquatic creatures in the deep

One major aid was his re-breather, a piece of aqualung technology that recaptures all the oxygen that a diver breathes out, and recycles it. This enables swimmers to stay under for much longer without replacing their air tanks. It also reduces the amount of bubbles from the mouthpiece, which can spook underwater creatures.

Staying out of the limelight

In the twilight zone, deep under the surface, the faintest glimmer in the wrong place can cost a fish its life. Creatures such as the Fang Tooth roam the depths, snapping at anything that moves or glows.

Prey species, including fish such as barreleyes (which have distinctive transparent heads), create luminous displays with their light-emitting organs, in an attempt to break up their outlines — just as zebras disguise themselves in the bright savannah light with their stripes.

Trying to film these fish with an underwater searchlight is pointless. They all flee from the deadly beam.

But in the final year of filming on Blue Planet II, new low-light cameras became available that are capable of seeing in near total darkness. The result is footage of fish behaviour never seen before, including remarkable pictures of mobula rays that emit a ghostly light that makes them look like animations.

Looking for a fish? Hire a dolphin 

The Blue Planet II team were eager to witness the so-called ‘boiling sea’. This is caused by enormous shoals of lanternfish, millions upon millions of them, being herded up to the surface by predators. As they try to escape being eaten, the sea teems and bubbles.

To film it, the camera team flew to the Coral Sea, off the coast of Australia, but rises in sea temperature — believed to be caused by climate change — prevented the shoals from forming. Eighteen months later, they tried again — but instead of Australia, this time they went looking off the coast of California.

Aboard a research vessel called the Alucia, they used a helicopter to search… not for the lanternfish but for super-pods of spinner dolphins (these groups can have as many as 10,000 members).

Dolphins are much better at hunting out fishy prey than humans, and soon led the cameras straight to the action.

There, they filmed the dolphins corralling the lanternfish into tight balls, and saw giant yellowfin tuna joining in the feast. Before long, the seas really did appear to be boiling.

As well as aerial shots from the helicopter, the crew towed a camera behind a boat to film from right inside the maelstrom.

Sealions use sheepdog trick

Producer Miles Barton was sceptical when a Galapagos fisherman contacted researchers to claim he had seen sealions herding yellowfin tuna, like dogs with sheep.

‘I found it hard to believe,’ Miles said. ‘So we gave the fisherman a GoPro, a portable video camera like the ones cyclists wear on their helmets, and told him to get us some footage to prove it!’ To the producer’s amazement, the grainy video showed behaviour that had never been recorded by scientists, let alone captured for TV.

But there was a problem: to film the sealions properly, the team would have to contend with Galapagos sharks.

The sealions were herding the tuna into coastal inlets, trapping them, and then killing them with a single bite to the back of the neck. It was a sophisticated and effective hunting technique. But the blood in the water quickly attracted the sharks which snapped at anything they saw, including the crew.

This problem was compounded by the fact that sharks are also sensitive to electrical impulses and bright lights which can both signal the presence of prey — a fully kitted-out camera crew must have looked like a slap-up meal.The cameras themselves were robust enough to withstand bites, but the team were obliged to wear whole-body ‘shark suits’ made of chainmail over their wetsuits, which protected them from bites but made heavy work of swimming.

A diver armed with a ‘shark stick’, like an electric cattle prod, was also close by to protect them, and by limiting their use of flashes they were able to keep unwanted attention to a minimum.

Whale of a time taking selfies

Not everybody entrusted with a camera during the filming of Blue Planet II was a human. Fingers is a female sperm whale, about 35ft long, and she has a calf called Digit who is learning to hunt with her in the Caribbean waters off the island of Domenica.

Using a long pole and four suction pads, a camera was attached to Fingers’s flank, just ahead of her dorsal fin.

It captured intimate footage of the whale family at play, deep below the waves and completely unaware they were being watched. The cameras pop off the whale’s bodies automatically after a few days. Radio locators then help the teams to find them.

A case of split personality

One signature shot on Blue Planet II is the split-screen, with the camera looking simultaneously above and below the waves.

This is done with a Megadome, a camera with a wide-angle lens that gives a clear picture of what’s happening both on and under the surface — especially effective when filming walruses as they slide off ice floes into the water. The camera rig, which weighs 110lb, requires three people to manoeuvre it into the water.

‘It’s an ordeal to get it going,’ says David Reichert, who steers it through the sea with his flippers.

The Megadome requires smooth seas (choppy waves make for bad television) so the crew had to be prepared for filming at any moment. Some of the best shots of the walruses were done at 4am: during summer in the Arctic, the sun doesn’t set for weeks on end, so filming at any hour is possible.

Sub that sprung a leak going half a mile down 

Mini-submarines played such a crucial role that the teams clocked up more than 1,000 hours in these underwater camera pods.

Producer Orla Doherty took part in about half the missions, spending more than 500 hours in submersibles, capturing on film such odd creatures as sea toads, which march across the ocean bed on their stubby pectoral and pelvic fins.

The Blue Planet II team worked with several submarines to film the Deep episode

The Blue Planet II team worked with several submarines to film the Deep episode

Many dives went down about half a mile with the descent alone taking about an hour — but the crew would still have to spend eight hours filming. ‘That’s a long time to go without a loo break,’ says Orla.

There was a heart-stopping moment for her when, a third of a mile below the icy surface of the Antarctic Ocean, the intense cold damaged the seal on one of the pressure gauges. It began to leak, and a pool of water gathered at the bottom of the sub.

For 20 minutes the crew worked frantically to find the leak and fix it before it ripped or ruptured, which would have meant instant death.


A big noise under water

Quadrophonic surround sound, once the delight of hi-fi enthusiasts, has become an invaluable tool for marine research.

Dr Steve Simpson of the University of Exeter has invented an underwater rig with four giant microphones that enables him to home in on sounds in any direction. ‘We can work out who is making noises and why,’ he says. ‘We now know that fish larvae listen in to the coral reef and then choose where to make their home.’

Striking it lucky with the turtles

The arrival of the olive ridley sea turtles — named for their green shells — on the Costa Rican beach where they will lay their eggs is one of the wonders of the natural world. Known as the ‘arribada’ (Spanish for ‘arrival’), this event can happen at any time between September and December.

Ostional Beach on Costa Rica’s Pacific coast is one of the key sites. But to leave a camera team waiting there for months was too expensive. Instead, a unit was kept on standby in the capital of San José, eight hours’ drive away, ready to scramble at a moment’s notice.

But they were beaten to it. A Costa Rica footballer tweeted a selfie with the turtles to his huge social media following. Within hours, Ostional Beach was inundated with sightseers.

Filming amid the mayhem was impossible. It took 18 months more planning and waiting before another large enough arribada.

  • Blue Planet II: A New World Of Hidden Depths by James Honeyborne and Mark Brownlow (BBC Books, £25).