Planet Earth III: Ocean (BBC One Sunday 29 October 2023)

Planet Earth III: Ocean airs Sunday 29 October 2023 on BBC One

What can we expect from this episode

Since the majority of our planet is water, there are vast areas that have not been mapped. Eighty percent of all animal species are found in the ocean, which covers two-thirds of the planet. There is still a lot we don’t know. This groundbreaking film, presented by Sir David Attenborough, explores the ocean’s vastness and diversity in order to shed light on the extraordinary behaviours and adaptations necessary for life there.

Even predators like the deadly lionfish need to be wary of the shallow seas of the tropics, despite their idyllic appearance. The appearances are deceiving. In order to catch prey, the clown frogfish, the reef’s most extraordinary hunter, uses a fishing rod attached to its head and a shrimp-like lure that can be fatally alluring.

Giant kelp forests thrive in the cold waters off North America, far from the tropics. Young horn sharks should avoid this area. The kelp is patrolled by giant sea bass and even larger sharks. However, the real threat lies beneath the surface. An angel shark ambushes a little horn shark that wandered into its trap. When struck by lightning, it disappears entirely. But that’s not all; the little horn shark has a sneak attack up its sleeve.

The kelp beds can be torn apart by winter storms, releasing the kelp into the open sea. Floating kelp provides a crucial lifeline for creatures like flying fish, which rely on it to lay their eggs out in the open ocean. They must lay thousands of eggs, though, because blue sharks love to snack on them.

These seaweed islands are crucial to the survival of marine life in the open ocean, but they are rapidly being displaced by plastic. Each year, 12 million tonnes of trash are dumped into the sea. Some animals have figured out how to use these plastic rafts to their advantage, despite the fact that they are deadly for most. Here we have the Columbus crab. A sea creature with a serious issue. Because of their poor swimming abilities, Columbus crabs rely on hitchhiking to reach potential mates. In fact, passing turtles can serve as a permanent home for a crab couple. These turtles provide a comfortable home for a pair of Columbus crabs who groom each other in exchange for food and shelter.

The ocean can be a difficult place to find a lifelong companion. Mobula rays in the Sea of Cortez perform incredible acrobatics to gather a large population of other rays. However, a family of orca that specialises in hunting rays uses a novel tactic to capture these elusive creatures, and they have been drawn to the area by all the noise.

The ocean’s depths are one of its least explored regions. Specialised vessels that can withstand the intense pressure are needed to travel there. As you descend deeper, the sunlight begins to dim, and you enter a strange new world where you might come across a gulper eel with jaws that can swallow prey larger than its own body, or a massive siphonophore that is longer than a blue whale.

Temperatures at the seafloor two miles down are so low that it would take a mother pearl octopus egg over ten years to develop. She visits a unique spot where thermal spa water is generated by hot water rising from the ocean floor. There are also approximately 20,000 other female octopuses in the area, all of whom are there to lay eggs. Even though the warm water speeds up the development of her eggs, she will not abandon them for a full two years, not even to feed. This extraordinary exertion will prove fatal to her.

The ocean animals of today must contend with human activity. South American sea lions off the coast of Chile have figured out some pretty ingenious ways to steal fish from fishermen’s nets, and they do it by the thousands every year. The sea lions have a limited amount of time to escape the net before they are trapped and drowned. Young and immature animals often cannot escape in time, and as a result, some of them perish.

Animals in the ocean have evolved tremendously to meet the challenges of their environment. But can they handle the new pressure of living in close proximity to us?

Combining the awe and wonder of the original Planet Earth, the new science and discoveries of Blue Planet II and Planet Earth II, and the immersive character-led storytelling of Dynasties, Planet Earth III will take the experience to new heights.

Season 1 Episode 2

When can we see the episode

Planet Earth III: Ocean airs Sunday 29 October 2023 at 18:20 on BBC One

Featured image credit: BBC One