Sir David Attenborough reveals the findings of one of the most ambitious scientific studies of our time - an investigation into what is happening to our oceans. He looks at whether it is too late to save their remarkable biodiversity. Attenborough explores some of the ways in which we are affecting marine life - from over-fishing to the acidification of sea water. The film also uncovers the disturbing story of how shipping noise is deafening whales and dolphins, affecting their survival in the future.

Hunger at Sea follows blue whales, sharks, sea lions, frigatebirds, dolphins and albatrosses to reveal the strategies they use to hunt for prey in the big blue. The open ocean is an immense wilderness that covers more than half the surface of our planet, yet for the most part it's a watery desert, largely devoid of life. Predators face an endless search to find and catch food, yet these great tracts of ocean are home to some of the most remarkable hunters on the planet.

The coast is the dynamic border between land and sea; powered by the tides and thrashed by waves, this is a world of continuous change. Opportunities never last long here, so hunters are always in a race against time. The coast is the only place on the planet where predators from air, land and sea come together. Dolphins that leave the safety of the sea to fish, walking octopuses, ingenious monkeys, fishing wolves and the greatest gathering of feeding humpback whales come to the coast to hunt. For all, timing is everything.

The final episode of the series visits the frontline of the conflict with the world's top predators, meeting the scientists fighting to save them. Crossing five continents and combining landmark natural history footage with real-life human drama, it checks the pulse of the earth's iconic animals, including lions, tigers, polar bears and blue whales. With three-quarters of the planet's carnivores now in decline, can people find ways to live with predators before they disappear forever?

The contests between predators and prey are the most dramatic events in nature. Taking an intimate and detailed look at the remarkable strategies employed by hunters to catch their prey and the hunted to escape. Sir David Attenborough narrates. "The Hardest Challenge" reveals the extraordinary range of techniques predators use to catch their prey - from a leopard using all its powers of stealth to stalk impala in broad daylight to wild dogs, whose tactic is to wear down their prey over long distances; from Nile crocodiles, the planet's most patient predators, to killer whales who use teamwork and intelligence to take on humpback whales. But even with these finely tuned strategies, the outcome is far from certain. Surprisingly, most predators fail most of the time.

The stunning beauty of an island paradise on a quest to find the perfect wave-riding experience. Nine-time world surfing champion Kelly Slater and Tahitian surfer Raimana Van Bastolaer and a group of friends seek out the best waves breaking on the reef at Tahiti's famed surf site Teahupo'o. As their quest unfolds, the audience is plunged beneath the surface of things, to explore the hidden forces at work shaping ocean waves and the islands that lie in their path. Amidst playful surfing action, we navigate the cosmos and an ocean storm in a search for the source and nature of a wave's energy. Exploring mountainous Tahiti, we are thrust into the turbulent volcanic past of the island and its neighbours and discover the seagoing, wave-riding roots of the islanders themselves -- a culture still rich in the music, dance and lore of the sea. Beneath the ocean, swimming with our surfers, we explore the stunning, fragile beauty of the reef habitat -- a turbulent, wave-shaping interface that envelops the island and nurtures the ocean's multitudes in motion -- fish, dolphins, sharks and whales. When the truly big surf arrives at Teahupo'o, surfing play becomes surfing survival as the riders artfully tackle some of the heaviest surf on the planet -- spectacularly captured for the giant screen in 3D for the first time.