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[radio static]

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[beep]

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[indistinct radio chatter]

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[David Attenborough] <i>Just 50 years ago,</i>

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<i>we finally ventured to the Moon.</i>

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<i>For the very first time,</i>

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<i>we looked back at our own planet.</i>

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<i>Since then, the human population</i>
<i>has more than doubled.</i>

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<i>This series will celebrate</i>
<i>the natural wonders that remain</i>

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<i>and reveal what we must preserve</i>

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<i>to ensure people and nature thrive.</i>

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<i>Dolphins...</i>

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<i>panicking.</i>

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<i>They're being hunted</i>
<i>by false killer whales.</i>

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[birds cawing]

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<i>Dolphins are faster in short bursts.</i>

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<i>But their hunters have stamina.</i>

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<i>Just as the killer whales close in,</i>

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<i>the dolphins make a sudden turn</i>
<i>to evade their predators.</i>

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<i>These extraordinary events</i>
<i>are taking place far from land,</i>

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<i>where few of us ever venture.</i>

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<i>This is the ocean</i>
<i>beyond the boundary of any country...</i>

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<i>largely ungoverned, wild, and lawless.</i>

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<i>Nothing symbolizes</i>
<i>our relationship with the high seas</i>

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<i>better than the blue whale.</i>

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<i>Weighing 200 tons and 30 meters long,</i>

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<i>these are the largest animals</i>
<i>ever to have existed.</i>

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<i>Yet much of their lives</i>
<i>is still a mystery to us.</i>

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<i>Blue whales live far out to sea,</i>

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<i>roaming every ocean</i>
<i>from the tropics to the poles.</i>

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<i>We have only recently discovered</i>

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<i>a few special places</i>
<i>where they come close to shore.</i>

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<i>The Gulf of California,</i>

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<i>on Mexico's Pacific coast.</i>

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<i>This is a sanctuary for blue whales.</i>

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[whale huffing]

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<i>Meet the world's biggest newborn...</i>

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<i>a baby blue.</i>

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<i>Just a month old,</i>

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<i>she's already eight meters long</i>
<i>and weighs six tons.</i>

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<i>Her mother shelters her</i>
<i>with a protective fin.</i>

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<i>They caress one another,</i>
<i>cherishing their close bond.</i>

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<i>These are the most intimate images</i>
<i>ever captured</i>

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<i>of a blue whale mother and her calf.</i>

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<i>This female will give birth</i>
<i>only once every two or three years,</i>

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<i>so each baby blue is extremely precious.</i>

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<i>The calf will grow three tons a month.</i>

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<i>Once, there were</i>
<i>more than</i> <i>300,000 blue whales,</i>

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<i>but last century,</i>
<i>they were hunted relentlessly,</i>

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<i>and only a few thousand survived.</i>

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<i>Blue whales are now protected,</i>

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<i>and their numbers are slowly increasing.</i>

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<i>Soon, this calf will leave</i>
<i>these sheltered waters</i>

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<i>to roam the high seas.</i>

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<i>We once thought that the high seas</i>
<i>were simply too vast for us to damage,</i>

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<i>but we now know that her ocean home</i>
<i>is under threat as never before.</i>

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<i>Out here in the big blue,</i>
<i>there remain a few pristine places</i>

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<i>to remind us</i>
<i>how rich the oceans can still be.</i>

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<i>Spinner dolphins.</i>

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<i>In the Pacific, off the coast</i>
<i>of Costa Rica, Central America,</i>

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<i>they are starting to gather</i>
<i>in great numbers.</i>
<i>Spinners live in pods,</i>

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<i>groups of individuals</i>
<i>linked by complex social relationships.</i>

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[dolphins clicking]

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<i>The dolphins constantly touch</i>
<i>and talk with one another,</i>

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<i>using a language of clicks and whistles.</i>

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[dolphins clicking and chittering]

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<i>They are shadowed by yellowfin tuna.</i>

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<i>The tuna rely on the dolphins</i>
<i>to find food.</i>

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<i>Everyone is searching for the same prey...</i>

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<i>lantern fish...</i>

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<i>the most numerous fish on the planet.</i>

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<i>No longer than your finger,</i>

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<i>lantern fish spend most of their time</i>
<i>hiding in the deep.</i>

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<i>So, despite their astounding abundance,</i>
<i>we don't fish for them.</i>

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<i>They are one of the few fish</i>
<i>that still thrives.</i>

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<i>As they close in on their prey,</i>
<i>the dolphin pod gets bigger and bigger.</i>

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<i>This pod could be 10,000 strong.</i>

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<i>For every one at the surface,</i>
<i>20 swim below.</i>

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[dolphins clicking]

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<i>Using echolocation, a type of sonar,</i>

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<i>the dolphins detect lantern fish</i>
<i>in the depths</i>

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<i>and drive them to the surface.</i>

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<i>They patrol the underside of the shoal</i>

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<i>to stop their prey</i>
<i>escaping back to the deep.</i>

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[clicking and chittering]

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<i>Once the dolphins have had their fill,</i>

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<i>there's still plenty more</i>
<i>for other predators.</i>

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<i>Mobula rays swoop in.</i>

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<i>To maximize their catch,</i>
<i>the rays attack in formation.</i>

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<i>A wall of mouths scooping up their prey.</i>

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<i>Because we don't fish for them,</i>
<i>lantern fish and their predators thrive.</i>

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<i>All these hunters have barely made a dent</i>
<i>in the great shoal.</i>

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<i>Most life in the open ocean</i>
<i>is concentrated in a thin surface layer,</i>

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<i>where the power of the sun</i>
<i>has its greatest effect.</i>

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<i>These sunlit shallows</i>
<i>are fertilized in a surprising way.</i>

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<i>As the dolphins produce waste,</i>
<i>they play a vital role,</i>

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<i>recycling nutrients from the deep</i>
<i>up to the surface.</i>

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[dolphins chittering]

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<i>This marine manure</i>

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<i>helps to fuel the basis</i>
<i>of all life in the open ocean.</i>

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<i>Phytoplankton...</i>

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<i>microscopic drifting plants.</i>

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<i>They combine nutrients in seawater</i>
<i>with energy from the sun</i>

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<i>to create the very foundation</i>
<i>of every food chain out here.</i>

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<i>So all animals, from the smallest fish</i>
<i>to the largest whale,</i>

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<i>ultimately depend</i>
<i>on these tiny plants for food.</i>

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<i>And in turn, the phytoplankton</i>
<i>benefits from the nutrients</i>

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<i>produced by these animals.</i>

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<i>Crucially, phytoplankton also produce</i>
<i>half the oxygen in the air we breathe.</i>

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<i>So, no matter where you live,</i>

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<i>you can thank</i>
<i>these exquisite little plants</i>

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<i>for every other breath you take.</i>

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<i>In ideal conditions,</i>
<i>they can bloom to such an extent</i>

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<i>that great swathes of the ocean</i>
<i>turn green.</i>

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<i>Surprisingly, phytoplankton</i>
<i>also play a vital role in cloud formation.</i>

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[thunder rumbling]

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<i>Moisture evaporating from the ocean</i>

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<i>condenses around</i>
<i>tiny particles created by the plankton.</i>

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<i>These droplets combine</i>
<i>to grow into colossal clouds.</i>

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<i>They can rise 20 kilometers</i>
<i>into the atmosphere.</i>

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<i>These oceanic clouds</i>
<i>reflect the sun's energy back into space,</i>

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<i>helping to protect the Earth</i>
<i>from rising temperatures.</i>

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<i>Not only do the oceans</i>
<i>produce half the oxygen we breathe,</i>

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<i>they also drive the weather and climate,</i>

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<i>transporting life-giving fresh water</i>
<i>around the world.</i>

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[thunder rumbling]

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<i>The high seas</i>
<i>are the life-support system of our planet.</i>

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<i>They have such power</i>
<i>simply because they're so vast.</i>

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<i>The oceans cover</i> <i>two-thirds of the globe,</i>
<i>and that's just the surface.</i>

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<i>They're also immensely deep.</i>

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<i>We can only journey</i>
<i>to this unexplored space</i>

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<i>in special submarines</i>
<i>that can withstand the crushing pressure.</i>

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<i>The average depth of the oceans</i>
<i>is nearly four kilometers,</i>

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<i>and the deepest point more than ten.</i>

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<i>The deep makes up 95 percent</i>
<i>of all the space available for life.</i>

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<i>This alien world</i>
<i>is home to weird and mysterious creatures.</i>

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<i>Few are stranger than this one.</i>

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<i>For years, we only knew they existed</i>
<i>from the occasional one washed ashore.</i>

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<i>They have hardly ever been seen alive.</i>

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<i>An oarfish.</i>

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<i>Ten meters long.</i>

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<i>Hanging vertically</i>

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<i>and using rhythmic waves</i>
<i>along their dorsal fin,</i>

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<i>oarfish commute easily</i>
<i>between the surface and the depths.</i>

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<i>Below 200 meters, there's not enough light</i>
<i>for plants to grow,</i>

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<i>so deep-sea animals depend on</i>
<i>food sinking down from the surface...</i>

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<i>marine snow.</i>

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<i>A crown jellyfish</i>
<i>drifts with tentacles outstretched</i>

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<i>to ensnare pray.</i>

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<i>They live in every ocean,</i>
<i>to depths of seven kilometers.</i>

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<i>The deep is so vast that these could be</i>
<i>the most abundant of all jellyfish.</i>

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<i>We used to think</i>
<i>the deep supported little life,</i>

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<i>but scientists now believe</i>

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00:21:01,469 --> 00:21:05,724
<i>there are ten times more animals</i>
<i>living here than previously thought.</i>

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<i>So, there must be many</i>
<i>yet to be discovered.</i>

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00:21:27,162 --> 00:21:33,293
<i>This deep-water crustacean, Cystisoma,</i>
<i>is as clear as glass.</i>

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00:21:37,589 --> 00:21:39,841
<i>It hides in plain sight.</i>

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00:21:43,845 --> 00:21:45,305
<i>In this twilight zone,</i>

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00:21:45,805 --> 00:21:51,644
<i>invisibility can be the difference</i>
<i>between finding a meal and being one.</i>

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00:21:56,232 --> 00:21:59,944
<i>Its huge eyes strain to see in the gloom.</i>

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00:22:09,954 --> 00:22:13,750
<i>No light penetrates</i>
<i>below a thousand meters.</i>

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00:22:18,338 --> 00:22:21,883
<i>In this darkness,</i>
<i>animals create their own light...</i>

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00:22:24,094 --> 00:22:25,720
<i>bioluminescence.</i>

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00:22:29,933 --> 00:22:36,523
<i>A glowing lure entices victims</i>
<i>into this dragonfish's terrifying teeth.</i>

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00:22:42,320 --> 00:22:47,409
<i>On most expeditions down here,</i>
<i>we are surprised by something new.</i>

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00:22:54,916 --> 00:22:57,293
<i>A deep-sea anglerfish.</i>

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00:23:00,713 --> 00:23:03,508
<i>Her extraordinary array of sensors</i>

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00:23:03,591 --> 00:23:08,888
<i>will detect even the faintest movement</i>
<i>by prey tempted to her lure.</i>

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00:23:15,103 --> 00:23:20,942
<i>Here, in the deep midwater,</i>
<i>predators play a patient game.</i>

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00:23:38,168 --> 00:23:40,545
<i>Eventually, we reach the bottom,</i>

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00:23:42,422 --> 00:23:44,716
<i>nearly a thousand meters down.</i>

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00:23:49,762 --> 00:23:54,017
<i>The deep-sea plains</i>
<i>cover more than half the Earth's surface,</i>

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00:23:56,144 --> 00:24:00,023
<i>and yet we know more</i>
<i>about the surface of the Moon.</i>

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00:24:06,779 --> 00:24:10,492
<i>Chimaera,</i>
<i>an ancient relative of the shark,</i>

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00:24:10,575 --> 00:24:12,035
<i>up to two meters long.</i>

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00:24:19,292 --> 00:24:24,506
<i>Few species of this size</i>
<i>can make a living on the barren seafloor.</i>

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00:24:30,011 --> 00:24:32,305
<i>Moving slowly to conserve energy,</i>

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00:24:32,847 --> 00:24:36,559
<i>they use special electrical sensors</i>
<i>around their mouths</i>

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00:24:36,643 --> 00:24:40,230
<i>to search for scarce prey</i>
<i>buried in the sediment.</i>

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00:24:49,822 --> 00:24:55,411
<i>Rocky outcrops rising from the seafloor</i>
<i>can be oases in this desert.</i>

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00:24:59,332 --> 00:25:02,919
<i>This ragged-tooth shark</i>
<i>has come here for good reason.</i>

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00:25:06,172 --> 00:25:09,008
<i>Five hundred meters down</i>
<i>off the coast of Florida,</i>

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00:25:09,509 --> 00:25:11,928
<i>a rare hot spot of life.</i>

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00:25:19,227 --> 00:25:22,564
<i>Lophelia, deep-sea coral reefs.</i>

185
00:25:39,497 --> 00:25:41,207
<i>We used to think that corals</i>

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00:25:41,291 --> 00:25:43,876
<i>were only found</i>
<i>in the warm, sunny shallows.</i>

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00:25:47,046 --> 00:25:52,594
<i>But, astonishingly, deep-sea reefs</i>
<i>cover a greater area of the seafloor</i>

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00:25:52,677 --> 00:25:54,721
<i>than their shallow-water relatives.</i>

189
00:26:03,062 --> 00:26:05,148
<i>These underwater forests</i>

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00:26:05,815 --> 00:26:10,486
<i>provide shelter and food</i>
<i>for a rich community of marine life.</i>

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00:26:15,700 --> 00:26:19,537
<i>They're also vital nurseries</i>
<i>for many deep-sea creatures.</i>

192
00:26:29,964 --> 00:26:33,968
<i>The corals are made up</i>
<i>of many anemone-like individuals,</i>

193
00:26:34,052 --> 00:26:39,223
<i>polyps that live in colonies</i>
<i>connected by a hard skeleton.</i>

194
00:26:47,190 --> 00:26:50,735
<i>The polyps</i>
<i>have stinging cells in their tentacles</i>

195
00:26:50,818 --> 00:26:54,656
<i>to snare passing prey,</i>
<i>their only source of food.</i>

196
00:27:00,370 --> 00:27:03,414
<i>But they don't always</i>
<i>get to keep their catch.</i>

197
00:27:06,751 --> 00:27:10,213
<i>A bristle worm has set up home</i>
<i>within the coral.</i>

198
00:27:17,053 --> 00:27:20,306
<i>It checks the polyps</i>
<i>for a freshly caught morsel...</i>

199
00:27:22,600 --> 00:27:25,019
<i>and steals it from the coral.</i>

200
00:27:27,897 --> 00:27:31,401
<i>But this theft</i>
<i>is actually a protection racket.</i>

201
00:27:37,907 --> 00:27:41,077
<i>Urchins attack and eat the corals.</i>

202
00:27:44,163 --> 00:27:45,957
<i>Time for payback.</i>

203
00:27:47,834 --> 00:27:52,338
<i>The urchin may have protective spines,</i>
<i>but the worm has a shocking weapon,</i>

204
00:27:54,215 --> 00:27:55,550
<i>and goes on the attack.</i>

205
00:28:18,281 --> 00:28:20,450
<i>The urchin has been seen off,</i>

206
00:28:22,243 --> 00:28:25,121
<i>and the worm has saved its home.</i>

207
00:28:27,206 --> 00:28:29,208
<i>Like most deep-sea animals,</i>

208
00:28:31,169 --> 00:28:34,172
<i>these corals grow extremely slowly.</i>

209
00:28:36,507 --> 00:28:39,802
<i>Some reefs may be 40,000 years old.</i>

210
00:28:41,053 --> 00:28:46,934
<i>Despite being so far beneath the surface,</i>
<i>these corals are still within our reach.</i>

211
00:28:53,065 --> 00:28:56,694
<i>Deep-sea fishing nets</i>
<i>dragged across the seafloor</i>

212
00:28:56,778 --> 00:28:59,447
<i>reduce the fragile reefs to rubble.</i>

213
00:29:01,741 --> 00:29:06,120
<i>Half of all deep-sea corals</i>
<i>have already been destroyed.</i>

214
00:29:07,371 --> 00:29:10,833
<i>It will take centuries</i>
<i>for these communities to recover.</i>

215
00:29:23,054 --> 00:29:25,890
<i>Beyond the boundary of any one country,</i>

216
00:29:26,349 --> 00:29:30,019
<i>the high seas</i>
<i>are wild and barely protected.</i>

217
00:29:33,940 --> 00:29:36,526
<i>Wildest of all, the Southern Ocean,</i>

218
00:29:39,028 --> 00:29:40,988
<i>home of the albatross.</i>

219
00:29:49,205 --> 00:29:53,543
<i>Albatross live solitary lives</i>
<i>far out to sea.</i>

220
00:29:59,382 --> 00:30:02,134
<i>They can travel</i>
<i>hundreds of kilometers a day,</i>

221
00:30:02,218 --> 00:30:05,805
<i>often for weeks at a time,</i>
<i>searching for food.</i>

222
00:30:10,101 --> 00:30:13,437
<i>A dead sea lion is a rare opportunity.</i>

223
00:30:24,198 --> 00:30:26,868
<i>Giant petrels are the first to arrive.</i>

224
00:30:29,620 --> 00:30:33,332
<i>They use their powerful beaks</i>
<i>to rip the carcass open.</i>

225
00:30:35,668 --> 00:30:37,128
<i>Known as sea vultures,</i>

226
00:30:37,211 --> 00:30:40,923
<i>they are the top scavenger</i>
<i>in Antarctic waters.</i>

227
00:30:45,595 --> 00:30:47,597
[cawing]

228
00:30:54,145 --> 00:30:58,232
<i>Black-browed albatross</i>
<i>have an extraordinary sense of smell</i>

229
00:30:58,316 --> 00:31:01,819
<i>and can follow a scent</i>
<i>from 20 kilometers away.</i>

230
00:31:06,657 --> 00:31:09,660
<i>The black-browed</i>
<i>must grab mouthfuls when they can.</i>

231
00:31:15,041 --> 00:31:19,503
<i>They are bullied</i>
<i>by the more aggressive giant petrels.</i>

232
00:31:37,229 --> 00:31:39,941
<i>Wilson's petrels are too small to compete</i>

233
00:31:40,024 --> 00:31:43,027
<i>and pick off scraps</i>
<i>from the edge of the frenzy.</i>

234
00:31:48,658 --> 00:31:53,663
<i>These delicate little petrels</i>
<i>are the most numerous of all seabirds</i>

235
00:31:53,746 --> 00:31:55,873
<i>because they're found in every ocean.</i>

236
00:31:58,668 --> 00:32:00,252
[cawing and squawking]

237
00:32:03,506 --> 00:32:06,008
<i>It's only when</i>
<i>these normally solitary birds</i>

238
00:32:06,092 --> 00:32:07,385
<i>gather like this</i>

239
00:32:07,468 --> 00:32:12,139
<i>that we can appreciate the wealth of life</i>
<i>supported by the high seas.</i>

240
00:32:25,903 --> 00:32:29,448
<i>A wandering albatross is last to arrive.</i>

241
00:32:37,623 --> 00:32:41,669
<i>It dwarfs the other birds</i>
<i>and uses its great size</i>

242
00:32:42,586 --> 00:32:45,673
<i>and three-meter wingspan to dominate.</i>

243
00:32:56,308 --> 00:32:58,811
<i>Even the giant petrels back off.</i>

244
00:33:11,907 --> 00:33:14,535
<i>The wanderer finally gets its share.</i>

245
00:33:26,672 --> 00:33:30,051
<i>In recent years,</i>
<i>albatross and other seabirds</i>

246
00:33:30,134 --> 00:33:31,719
<i>have been in decline.</i>

247
00:33:33,679 --> 00:33:37,016
<i>Their need to travel great distances</i>
<i>exposes them</i>

248
00:33:37,099 --> 00:33:41,812
<i>to the dangers of a poorly regulated</i>
<i>and overexploited ocean.</i>

249
00:33:43,647 --> 00:33:46,901
<i>It's a problem</i>
<i>for all hunters of the high seas.</i>

250
00:33:50,988 --> 00:33:55,493
<i>These giants cross entire oceans</i>
<i>in their search for food.</i>

251
00:33:58,871 --> 00:34:03,417
<i>They can grow over three meters long</i>
<i>and weigh half a ton.</i>

252
00:34:10,591 --> 00:34:11,967
<i>Bluefin tuna.</i>

253
00:34:14,720 --> 00:34:18,933
<i>They're streamlined to perfection</i>
<i>and built for speed.</i>

254
00:34:23,938 --> 00:34:27,316
<i>They hunt in great packs, hundreds strong.</i>

255
00:34:50,798 --> 00:34:53,759
<i>The target: a school of anchovies.</i>

256
00:35:08,232 --> 00:35:13,195
<i>They gently corral the anchovies</i>
<i>into a tight ball at the surface,</i>

257
00:35:16,532 --> 00:35:18,909
<i>careful not to cause panic.</i>

258
00:35:22,204 --> 00:35:24,039
<i>And then they attack.</i>

259
00:35:40,097 --> 00:35:42,558
<i>This is a highly coordinated hunt.</i>

260
00:35:42,641 --> 00:35:44,310
<i>The tuna take turns,</i>

261
00:35:44,393 --> 00:35:48,022
<i>striking from the same direction</i>
<i>to keep the anchovies on the run.</i>

262
00:35:56,655 --> 00:36:01,410
<i>After a mouthful, each bluefin peels off</i>
<i>to take its place at the rear.</i>

263
00:36:02,703 --> 00:36:05,748
<i>Wave after wave continues the assault.</i>

264
00:36:21,680 --> 00:36:23,974
<i>With their power and devastating pace,</i>

265
00:36:24,058 --> 00:36:28,479
<i>bluefin tuna are one of the ocean's</i>
<i>most impressive hunters.</i>

266
00:36:39,823 --> 00:36:43,452
<i>They are also</i>
<i>the most prized fish in the sea.</i>

267
00:36:46,163 --> 00:36:50,584
<i>So valuable</i>
<i>that a single bluefin can sell in Japan</i>

268
00:36:50,668 --> 00:36:52,711
<i>for over a million dollars.</i>

269
00:36:55,422 --> 00:36:57,591
<i>So, perhaps it's inevitable</i>

270
00:36:57,675 --> 00:37:00,803
<i>that they have been fished</i>
<i>almost to extinction.</i>

271
00:37:05,891 --> 00:37:09,520
<i>Bluefin tuna</i>
<i>are not the only ones in peril.</i>

272
00:37:13,732 --> 00:37:16,068
<i>Decades of unsustainable fishing</i>

273
00:37:16,151 --> 00:37:19,280
<i>have left many fish stocks</i>
<i>in serious decline.</i>

274
00:37:22,908 --> 00:37:25,119
<i>A third have collapsed altogether.</i>

275
00:37:29,164 --> 00:37:32,334
<i>Plastic pollution</i>
<i>is a grave issue for our oceans,</i>

276
00:37:33,168 --> 00:37:37,256
<i>but industrial overfishing</i>
<i>is far more dangerous.</i>

277
00:37:39,800 --> 00:37:43,387
<i>If we continue to harvest the seas</i>
<i>in this way,</i>

278
00:37:43,470 --> 00:37:46,056
<i>it's not just fisheries</i>
<i>that will collapse.</i>

279
00:37:48,726 --> 00:37:52,021
<i>The whole ocean system could follow.</i>

280
00:37:58,527 --> 00:38:02,323
<i>One hundred million sharks</i>
<i>are killed every year,</i>

281
00:38:04,074 --> 00:38:06,452
<i>just to make shark fin soup.</i>

282
00:38:16,462 --> 00:38:21,133
<i>Ninety percent of all large ocean hunters</i>
<i>have disappeared.</i>

283
00:38:25,888 --> 00:38:31,101
<i>Without them at the top of the food chain,</i>
<i>the whole community of marine life</i>

284
00:38:31,685 --> 00:38:35,314
<i>is declining</i>
<i>and changing beyond recognition.</i>

285
00:38:56,710 --> 00:39:00,798
<i>Squid are increasingly replacing fish.</i>

286
00:39:07,763 --> 00:39:12,518
<i>We have severely depleted</i>
<i>both their predators and competitors,</i>

287
00:39:13,685 --> 00:39:16,021
<i>so squid are taking over,</i>

288
00:39:19,274 --> 00:39:23,612
<i>an indication</i>
<i>of a serious imbalance in the oceans.</i>

289
00:39:29,743 --> 00:39:33,414
<i>Squid breed quickly</i>
<i>and have lots of fast-growing young,</i>

290
00:39:35,207 --> 00:39:40,129
<i>so they can rapidly exploit the gaps</i>
<i>left by the fish that we have harvested.</i>

291
00:39:42,256 --> 00:39:44,716
<i>They lay their eggs in cases</i>
<i>on the seafloor.</i>

292
00:39:44,800 --> 00:39:49,346
<i>The young develop even faster</i>
<i>in these warm, shallow waters.</i>

293
00:39:52,599 --> 00:39:55,769
<i>With such drastic changes</i>
<i>in the marine menu,</i>

294
00:39:55,853 --> 00:39:58,313
<i>predators are having to adapt.</i>

295
00:40:02,776 --> 00:40:06,363
<i>Sea lions prefer to eat</i>
<i>more energy-rich prey,</i>

296
00:40:06,447 --> 00:40:08,532
<i>like anchovies and sardines,</i>

297
00:40:09,324 --> 00:40:11,410
<i>but with these in short supply,</i>

298
00:40:11,493 --> 00:40:14,705
<i>they're forced to rely more</i>
<i>on a diet of squid.</i>

299
00:40:19,626 --> 00:40:23,213
<i>We, too, will be forced to change</i>
<i>the seafood we eat</i>

300
00:40:23,297 --> 00:40:25,716
<i>if we continue to fish as we do.</i>

301
00:40:29,845 --> 00:40:33,307
<i>But if we harvest the oceans</i>
<i>in a sustainable way,</i>

302
00:40:34,433 --> 00:40:36,727
<i>they can be marvelously productive</i>

303
00:40:37,728 --> 00:40:40,731
<i>and will provide us</i>
<i>with an abundance of food.</i>

304
00:40:46,862 --> 00:40:49,615
<i>There are already signs</i>
<i>that the ocean has the power</i>

305
00:40:49,698 --> 00:40:52,075
<i>to recover astonishingly quickly.</i>

306
00:41:02,002 --> 00:41:03,420
<i>Humpback whales.</i>

307
00:41:11,261 --> 00:41:13,305
<i>They live in every ocean,</i>

308
00:41:13,388 --> 00:41:16,892
<i>traveling the high seas,</i>
<i>from their polar feeding grounds</i>

309
00:41:16,975 --> 00:41:18,936
<i>to the tropics, where they breed.</i>

310
00:41:19,770 --> 00:41:21,104
[whale song]

311
00:41:22,940 --> 00:41:26,610
<i>Yet whales have not always enjoyed</i>
<i>such freedom.</i>

312
00:41:29,738 --> 00:41:33,116
<i>Once, there were</i>
<i>more than a hundred thousand humpbacks</i>

313
00:41:33,200 --> 00:41:34,076
<i>in the oceans,</i>

314
00:41:35,160 --> 00:41:39,122
<i>but last century,</i>
<i>they were hunted to near extinction.</i>

315
00:41:44,836 --> 00:41:48,215
<i>Just a few thousand</i>
<i>survived the onslaught.</i>

316
00:41:56,890 --> 00:41:58,809
<i>A huge public outcry</i>

317
00:41:59,226 --> 00:42:04,189
<i>finally led to a ban</i>
<i>on commercial whaling in 1986.</i>

318
00:42:07,776 --> 00:42:12,656
<i>Since then, the number of humpback whales</i>
<i>has been steadily increasing.</i>

319
00:42:18,662 --> 00:42:21,540
<i>They're returning</i>
<i>to their ancestral feeding grounds,</i>

320
00:42:21,623 --> 00:42:24,126
<i>like these off the coast of South Africa.</i>

321
00:42:26,086 --> 00:42:29,673
[whale song]

322
00:42:33,510 --> 00:42:38,098
<i>They are gathering to take advantage</i>
<i>of a seasonal abundance of krill,</i>

323
00:42:38,181 --> 00:42:40,225
<i>tiny shrimp-like crustaceans.</i>

324
00:42:52,821 --> 00:42:55,532
<i>The whales take in</i>
<i>great mouthfuls of water,</i>

325
00:42:56,283 --> 00:42:59,286
<i>trapping the krill</i>
<i>on sieves of hairy bristles</i>

326
00:42:59,369 --> 00:43:00,746
<i>that line their jaws.</i>

327
00:43:22,559 --> 00:43:25,854
<i>Each whale can eat over a ton a day.</i>

328
00:43:56,802 --> 00:44:01,765
<i>With food so plentiful,</i>
<i>fur seals come to claim their share.</i>

329
00:44:03,141 --> 00:44:07,145
[whale song]

330
00:44:24,871 --> 00:44:29,876
<i>These extraordinary scenes</i>
<i>were unimaginable just a few years ago.</i>

331
00:44:45,934 --> 00:44:49,354
<i>They form super-groups, hundreds strong.</i>

332
00:45:11,752 --> 00:45:17,048
<i>This is the greatest gathering of whales</i>
<i>seen for a century.</i>

333
00:45:37,235 --> 00:45:41,615
<i>Whales recycle nutrients</i>
<i>that enrich surface waters,</i>

334
00:45:42,157 --> 00:45:44,743
<i>which fuel the growth of phytoplankton,</i>

335
00:45:45,660 --> 00:45:50,624
<i>and they, in turn, feed krill</i>
<i>in a perfect self-sustaining cycle.</i>

336
00:45:53,585 --> 00:45:57,088
<i>We now know that a healthy community</i>
<i>of great hunters,</i>

337
00:45:57,172 --> 00:46:00,217
<i>whales, dolphins, tuna, and sharks,</i>

338
00:46:01,134 --> 00:46:04,137
<i>is essential</i>
<i>for a fully-functioning ocean.</i>

339
00:46:07,474 --> 00:46:11,937
<i>And a functioning ocean</i>
<i>is vital to the health of our planet</i>

340
00:46:12,562 --> 00:46:13,814
<i>and humanity.</i>

341
00:46:18,318 --> 00:46:20,570
<i>In a remarkable recovery,</i>

342
00:46:20,654 --> 00:46:24,491
<i>humpback whales have almost returned</i>
<i>to their original numbers.</i>

343
00:46:27,536 --> 00:46:29,538
<i>But during that time,</i>

344
00:46:29,621 --> 00:46:34,960
<i>we have done more harm to the oceans</i>
<i>than ever before in human history.</i>

345
00:46:44,344 --> 00:46:47,389
<i>Only with global cooperation</i>

346
00:46:47,472 --> 00:46:51,226
<i>will our oceans</i>
<i>recover and thrive once again.</i>

347
00:46:55,188 --> 00:46:58,650
<i>We saved the whales</i>
<i>by international agreement.</i>

348
00:47:01,069 --> 00:47:05,115
<i>Now, it is time to save our oceans.</i>

349
00:47:18,003 --> 00:47:22,841
<i>Please visit ourplanet.com</i>
<i>to discover what we need to do now</i>

350
00:47:22,924 --> 00:47:24,926
<i>to protect the high seas.</i>

351
00:47:27,387 --> 00:47:33,226
<i>♪ I can hear the whole world</i>
<i>Singing together ♪</i>

352
00:47:35,937 --> 00:47:41,818
<i>♪ I can hear the whole world</i>
<i>Say it's now or never ♪</i>

353
00:47:44,654 --> 00:47:48,950
<i>♪ 'Cause it's not too late</i>
<i>If we change our ways ♪</i>

354
00:47:49,034 --> 00:47:52,829
<i>♪ And connect the dots to our problems ♪</i>

355
00:47:52,913 --> 00:47:58,960
<i>♪ I can hear the whole world</i>
<i>Say we're in this together ♪</i>

356
00:47:59,044 --> 00:48:00,837
<i>♪ We're in this together ♪</i>