South Pacific

The opening episode presents an overview of the natural history of the region, introducing some of the themes that are explored in more detail in later programmes. The South Pacific covers a vast area, and less than 1% is land, ranging from the Hawaiian Islands north of the equator to New Zealand in the south. On Macquarie Island, the most southerly outpost before Antarctica, springtime sees the arrival of huge numbers of elephant seals. Aerial footage shows the entire world population of royal penguins, which nest here in a single colony. Cold ocean currents flow all the way to the Galápagos Islands, 8000 miles away, enabling sea lions and penguins to survive on the equator. Isolation has enabled the region’s wildlife to evolve in unusual ways. OnMetoma, robber crabs, the world’s largest terrestrial invertebrates, are filmed massing at night to feed on coconuts. On Hawaii, the most isolated archipelago of all, the caterpillars have turned carnivorous. There is an incredible diversity of human cultures and customs too, despitecolonisation taking place relatively recently. The men of Pentecost Island leap from timber scaffold towers with only a vine tied to their ankles to break their falls. On small islands such as Anuta, people have fostered strong communities and sustainable hunting, farming and fishing practices to make up for the limited availability of food. The story of Easter Island, where a whole civilization brought about their own downfall through over-exploitation of their resources, is a lesson from history.

The second instalment looks at how plants, animals and humans colonised even the most remote islands. Most pioneers came from the west, with New Guinea acting as the launch pad. The saltwater crocodile is one species which managed to swim the 60-mile crossing to the next island group, the Solomons. The mass spawning of groupers on a Solomon Island reef releases millions of eggs, which drift on ocean currents to establish new populations. The activity allows grey reef sharks to snatch a few distracted groupers. Few animals made it to Fiji, Tonga and Samoa, 1000 miles further east. Fruit bats were the only mammals to cross the ocean divide, but smaller animals were carried herebycyclones and jet stream winds. In the absence of ground predators, invertebrates have reached monstrous proportions. Fijian crested iguanas are thought to have floated here on rafts of vegetation. Seabirds have made the crossing to French Polynesia, where their rich guano helped fertilise barbed seeds stuck to their feathers and turn barrencoralatolls into fertile groves. One plant needs no such help. Coconuts can survive drifting for two months at sea and lay roots into bare sand. Before the arrival of humans, fewer than 500 species colonised Hawaii in 30 million years. Once established, they evolved into countless new varieties. The story of human colonisation is no less remarkable. The ancestors of modern Polynesians, most probably Lapitas of Southeast Asia, arrived in Fiji 3,500 years ago and Hawaii 2,000 years ago

The third programme begins in the tropics, where a white sperm whale calf stays close to its mother. The 19th century story of the Essex, with itswhalemen stranded in their lifeboats after a sperm whale attack is used to illustrate the difficulty of surviving in the open ocean. The currents which circle the South Pacific support huge shoals and an incredible variety of life, but much of the centre is an ocean desert. Nutrients are trapped at depth by thethermocline, making the windless surface clear but barren. Life can be tough for large predators. Some, including short-finned pilot whales, can dive to great depths to hunt squid. Others, like rare oceanic whitetip sharks, track the whales hoping for scraps or a chance to seize a young calf. The waters around the Galápagos teem with life thanks to the cool, nutrient-rich Antarctic current. Underwater footage showspenguins, manta rays and sea lions feeding. The sea lions work together to divide shoals into smaller bait balls, and blow bubbles into the reef to scare fish out. Seabirds are great ocean wanderers, but all must return to land to breed. On French Frigate Shoals, frigatebirds take sooty tern chicks from their nests, whilst offshore a dozen tiger sharks snatch any unfortunate black-footed albatross chicks that get their maiden flight wrong. Dusky dolphins and bull sperm whales are filmed in the waters off New Zealand, where an exhausted whale beached in a shallow bay is guided back out to sea by rescue boats.

The fourth instalment opens with rare footage of Kavachi, an underseavolcano, erupting. The South Pacific islands are typically volcanic in origin, and those of Hawaii are among the youngest. Kilauea’s rivers of lava flow directly into the sea, where they cool rapidly and release steam explosively. Pioneering species such as ōhia lehua colonise new land, putting roots down through the cracks into subterranean lava tubes where strange troglobites eke out their existence. In the Galápagos Islands, penguins take advantage of the cool shade of lava tubes to raise their chicks, but predatory Sally Lightfoot crabs lie in wait in the shadows. On the Solomons, megapodes bury their eggs in the warm ash of an active volcano, a natural incubator. Aerial photography ofMaunaKea, the Society Islands, Bora Bora and Rangiroa shows how erosion changes the character of volcanic islands over time. Eventually they sink back into the sea, leaving behind coral atolls and sheltered lagoons. Channels between ocean and lagoon attract feeding manta rays. The region’s coral reefs are the richest in the world-–the pristine Kingman Reef, a sunken volcano, has over 200 kinds of coral alone. Underwater footage includes giant clams spawning, grey reef sharks hunting needlefish by night andatimelapse sequence of a Triton’s trumpet engulfing a crown-of-thorns starfish. Reef fish are also agents of erosion-–thebumphead parrotfish chews through coral and excretes it as sand. The final scene shows huge swarms of jellyfish in themarine lakes of Palau, the jewel of Micronesia.

The fifth programme looks at the unusual animal life of the South Pacific. Species have evolved new behaviour to take advantage of ecological niches. On New Guinea, kangaroos such as the dingiso have become arboreal, taking the place of monkeys. The lack of predators on the ground has resulted in more flightless birds than anywhere else on Earth, including the kagu from New Caledonia. The Solomon Islands are home to the monkey-tailed skink, the largest of its kind. Unlike any of its relatives, it has a prehensile tail, forms social bonds and has turned vegetarian. The differing bill shapes of Hawaii’shoneycreepers are used to illustrate how one colonising species can evolve into many specialists. In New Zealand, Fiordland crested penguins raise their chicks in the forests and short-tailed bats behave more like mice, hunting wetas on the ground. The fate of some New Zealand animals illustrates the fragility of island life. The kakapo, once a successful and abundant herbivore, was defenceless against Māori hunters and introduced predators. There are now 70 millionAustralian possums in New Zealand’s forests, where they out-compete native wildlife. Controlling introduced species is a huge problem across the South Pacific. Wild tuataras can still be found on Stephens Island, but the flightless wren was not so lucky – the last of its kind were killed by pet cats before it was declared a new species. The collapse of the Rapanuicivilization on Easter Island shows that human beings are not immune to this precarious existence.

The final episode focuses on the environmental problems facing the South Pacific. Climate change threatens many islands, because they are low-lying and could be engulfed by rising seas. On Tuvalu, seawater bubbles up through the ground at high tides, making evacuation a realistic possibility. Oceans absorb half of all atmospheric CO2, but this turns them acidic, preventing sea creatures from building calciferous shells. The most immediate threat is overfishing. Reef damage by boats and tourism affects fish populations, but coral gardeners in Fiji have a solution. They harvest and grow corals artificially, then transplant them back to damaged reefs. Different fishing methods are compared, from sustainable pole and line fishingpractised by Solomon Islanders to long-line fishing, which has endangered albatross populations across the region. Commercial fishing vessels lay huge purse seine nets, large enough to catch 150 tonnes at a time. Cameras follow the action inside the net as a haul of yellowfin and skipjack tuna are brought to the surface. Greenpeace’s flagship Esperanzapatrols the high seas, unprotected pockets of ocean where fishing is unregulated. Less than 1% of the Pacific is protected, and yet up to 90% of its large predatory fish may have been lost already. A Fijian community reef is proof that protection could yet work. Tourism benefits from divers prepared to pay for close encounters with bull and tiger sharks, and fishermen benefit from increased stocks. An international conservation effort also helped save humpback whales, as numbers have recovered since the whaling ban.