Wild Isles Episode 5 Ocean - Interview with producer Gisle Sverdup

PHOTO: Basking shark (Cetorhinus maximus) (Image: BBC/Silverback Films/Alex Mustard/2020VISION/naturepl.com)

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What would you hope that the audience will take away from watching the series?

I hope that people watching this series will gain a new appreciation of how exciting and surprising the wildlife is on and around the British Isles. The Ocean episode showcases some of the amazingly colourful and charismatic animals living around our islands and I hope that it will change people’s perception of the diversity and importance of our seas.

Why are Britain and Ireland globally important for nature?

The seas around Britain and Ireland are crucially important to many species. The most obvious are our sea birds - 68% of the world population of Northern gannets depend on British and Irish waters*. And a huge number of the world’s population of Manx shearwaters nest on the little island of Skomer, off the Pembrokeshire coast. But other large animals also thrive here - 40% of the world’s grey seals hunt in our seas* and a major part of the global population of Basking sharks come to our shores in summer to feed and breed*. This all depends on the richness of our seas and we need to improve the way we treat our seas if we are to enjoy such wildlife wonders in our waters in the future.

What are the main challenges when filming underwater?

The main challenges for the ocean team were the ever-changing conditions on and in the sea. Sunny days are best for filming, but when working in the water, underwater visibility is also a major factor determining our success. The visibility could change daily, making what was a stunningly beautiful location on one day seem like green soup the next!

Do you think people will be surprised by the species that live in the waters around British and Ireland?

I absolutely believe that people will be surprised by the richness, diversity and colour of our underwater wildlife. What is fantastic is that a lot of it is accessible in shallow water.

And you had an encounter with a mighty basking shark as long as two buses*?

The basking shark is the largest fish in our waters*. This gentle giant might seem threatening, but it only eats some of the smallest inhabitants of the sea – the zooplankton. These are tiny animals and larvae that float around in the water and the basking shark simply has to swim around with an open mouth and collect them. Along the gills of the basking sharks are special sieve-like structures that separate the tiny animals from the sea water.

How did you film the bioluminescence scene? Did you use any new technology?

Bioluminescence is light made by algae and animals in the sea and it is surprisingly abundant in the ocean. But until recently, our cameras have not been light sensitive enough to capture these faint lights. For the bioluminescence sequence in the Ocean episode, we used a newly developed low light camera that could capture the bioluminescence in full 4K resolution.

About

If you thought our seas were cold, grey and lifeless, think again! In the fifth and final episode of Wild Isles, Sir David Attenborough introduces us to the colourful underwater world of Britain and Ireland’s oceans. This episode will take viewers below the waves to uncover the stories of the animals that live along 22,000 miles of our coastline.

In winter, clear evidence of the sea’s abundance can be seen on a beach in Norfolk. Thousands of grey seals congregate on the shoreline to give birth. The British Isles are home to 40% of the world’s population of grey seals, and the number being born on our shores rises every year.

Beyond the beach, the vibrant shallows contain several important habitats. Rich beds of sea grass act as important carbon storage areas, as well as providing home for seahorses. When night falls, tiny algae produce bright flashes of light when disturbed. This bioluminescence allows nearby cuttlefish to see their moving prey in the darkness.

On the shallow seabed, the spider crab undergoes a mass migration of epic scale. For just a few days every year, hordes of crabs march together as one. Others, like the slow-moving royal flush sea slug have a more mysterious way of migrating. They use the water currents to carry them to new areas, using their bodies like wings to swim up into a water column, hanging in the water like dancing fairies.

Where the water is forced through narrow gaps along the coast, powerful currents are created. The most awe-inspiring is the Corryvreckan Whirlpool on the Scottish west coast - the third largest whirlpool on the planet. Here, rising nutrients and penetrating sunbeams fuel a fresh blossoming of life, and our waters become a rich soup of tiny floating algae. The algae provide food for a group of alien-like animals called zooplankton, which in turn feed our largest fish, the basking shark. This gentle giant can grow to more than the length of a double decker bus, and it filters the water, open-mouthed, feeding on the tiny zooplankton.

Herring and mackerel form huge swirling shoals as they feed on plankton, and this attracts the attention of aerial hunters. Our seas support 68% of the world’s population of northern gannets and in summer, huge numbers of another seabird, the Manx shearwater, rely on our shores. In a touching piece to camera, Sir David Attenborough bids a fledgling chick farewell as it starts its journey many thousands of miles across the oceans to South America. There is no better example of how important the abundant seas of Britain and Ireland are to the survival of wildlife worldwide.

Confirmed for BBC One on 9 April at 7pm to 8pm.

Source BBC One