Original subtitles

[INFORMATION] [AUTHOR] [SOURCE] [PRG] [FILEPATH] [DELAY] [CD TRACK] [COMMENT] [END INFORMATION] [SUBTITLE] [COLF]&HFFFFFF,[STYLE]no,[SIZE]18,[FONT]Arial 00:00:35.00,00:00:38.00 Dwarfed by the vast expanse[br]of the open ocean

00:00:38.00,00:00:42.00 the biggest animal[br]that has ever lived on our planet.

00:00:48.01,00:00:52.01 A blue whale, 30 metres long[br]and weighing over 200 tonnes

00:00:54.02,00:00:58.01 It's far bigger[br]than even the biggest dinosaur

00:00:59.03,00:01:02.03 Its tongue weighs as much as an elephant

00:01:02.03,00:01:05.03 Its heart is the size of a car

00:01:05.03,00:01:09.02 And some of its blood vessels are so wide[br]that you could swim down them

00:01:11.04,00:01:15.03 Its tail alone is the width[br]of a small aircraft wings

00:01:34.06,00:01:38.05 Its streamlining, close to perfection,[br]enables it to cruise at twenty knots

00:01:39.07,00:01:43.06 It's one of the fastest animals in the sea

00:01:47.07,00:01:51.07 The ocean's largest inhabitant feeds[br]Almost exclusively on one of the smallest

00:01:52.08,00:01:56.07 krill, a crustacean[br]just a few centimetres long

00:02:00.09,00:02:04.09 Gathered in a shoal,[br]krill stain the sea red and a single blue

00:02:04.09,00:02:08.08 whale in a day[br]can consume forty million of them

00:02:17.10,00:02:21.10 Despite the enormous size of blue whales,[br]we know very little about them

00:02:22.11,00:02:24.11 Their migration[br]routes are still a mystery and

00:02:24.11,00:02:28.10 we have absolutely no idea[br]where they go to breed

00:02:32.12,00:02:35.12 They are a dramatic reminder of how much

00:02:35.12,00:02:39.11 we still have to learn about the ocean and[br]the creatures that live there

00:02:43.13,00:02:45.13 Our planet is a blue planet

00:02:45.13,00:02:49.12 Over seventy percent of[br]it is covered by the sea

00:02:52.14,00:02:54.14 The Pacific Ocean[br]alone covers half the globe

00:02:54.14,00:02:57.14 You can fly across it non-stop[br]for twelve hours

00:02:57.14,00:03:01.14 and still see nothing[br]more than a speck of land

00:03:02.15,00:03:06.14 This series will reveal the complete[br]natural history of our ocean planet from

00:03:07.15,00:03:11.15 its familiar shores to the mysteries[br]of its deepest seas

00:03:23.17,00:03:27.16 By volume, the ocean makes up 97% of[br]the earth inhabitable space

00:03:28.17,00:03:30.18 And the sheer quantity of marine life

00:03:30.18,00:03:34.17 it contains far exceeds that[br]which inhabits the land

00:03:57.20,00:03:59.21 But life in the ocean[br]is not evenly spread.

00:03:59.21,00:04:03.21 It's regulated by the path[br]of currents carrying nutrients

00:04:03.21,00:04:07.20 and the varying power of the sun

00:04:08.21,00:04:11.22 In this first programme[br]we will see how these two forces interact

00:04:11.22,00:04:15.21 to control the distribution of life[br]from the coral seas ...to the polar wastes

00:05:12.28,00:05:16.27 The sheer physical power[br]of the ocean dominates our planet

00:05:33.30,00:05:37.30 It profoundly influences[br]the weather of all the world

00:05:37.30,00:05:39.31 Water vapour rising[br]from it forms the clouds

00:05:39.31,00:05:43.30 and generates the storms that ultimately[br]will drench the land

00:06:03.33,00:06:06.33 The great waves[br]that roar in towards the shores

00:06:06.33,00:06:10.33 are dramatic demonstrations of its power

00:06:23.35,00:06:27.35 Waves originate far out at sea

00:06:27.35,00:06:30.36 There,[br]even gentle breezes can cause ripples

00:06:30.36,00:06:34.35 and ripples grow into swells

00:06:42.37,00:06:46.36 Out in the open ocean, unimpeded by land,[br]such swells can become gigantic

00:07:10.40,00:07:13.40 It's only when an ocean swell[br]eventually reaches shallow water

00:07:13.40,00:07:17.39 that it starts to break

00:07:23.41,00:07:24.41 As it approaches the coast

00:07:24.41,00:07:28.40 the water at the bottom of the swell[br]is slowed by contact with the sea bed

00:07:29.42,00:07:32.42 The top of the swell,[br]still travelling fast,

00:07:32.42,00:07:36.41 starts to roll over[br]and so the wave breaks

00:08:07.45,00:08:08.45 The ocean never rests.

00:08:08.45,00:08:11.46 Huge currents, such as the Gulf Stream,

00:08:11.46,00:08:15.46 keep its waters constantly[br]on the move all round the globe

00:08:15.46,00:08:17.46 It's these currents[br]more than any other factor

00:08:17.46,00:08:21.46 that control the distribution of[br]nutrients and life in the seas

00:08:25.47,00:08:28.47 A tiny island lost in the midst[br]of the Pacific

00:08:28.47,00:08:30.48 It's the tip of a huge mountain

00:08:30.48,00:08:34.47 that rises precipitously from[br]the sea floor thousands of metres below

00:08:40.49,00:08:44.48 The nearest land[br]is three hundred miles away

00:08:47.49,00:08:51.50 Isolated sea mounts[br]like this one create oases

00:08:51.50,00:08:53.50 where life can flourish...

00:08:53.50,00:08:57.49 in the comparatively empty expanses[br]of the open ocean

00:09:05.51,00:09:08.51 But all the creatures[br]that swim beside it would

00:09:08.51,00:09:12.51 not be here were it not for[br]one key factor - the deep ocean currents

00:09:19.53,00:09:23.53 Far below the surface they collide with[br]the island's flanks

00:09:23.53,00:09:25.53 and are deflected upwards

00:09:25.53,00:09:29.52 bringing with them from the depths[br]a rich soup of nutrients

00:09:32.54,00:09:36.53 Such up-wellings[br]attract great concentrations of life

00:09:44.55,00:09:47.55 Most of the fish here[br]are permanent residents,

00:09:47.55,00:09:51.56 feeding on the plankton, the tiny floating[br]plants and animals that are nourished

00:09:51.56,00:09:54.56 by the richness brought up from the depths

00:09:54.56,00:09:58.55 And they in turn,[br]attract visitors from the open ocean

00:09:59.57,00:10:03.56 Tuna.

00:10:26.59,00:10:30.59 The plankton feeders are easy targets

00:10:40.61,00:10:44.60 All this action attracts[br]even larger predators...

00:10:46.61,00:10:50.61 Sharks!

00:10:52.62,00:10:56.62 Hundreds of sharks.

00:10:56.62,00:11:00.63 These silky sharks are[br]normally ocean-going species

00:11:00.63,00:11:02.63 but the sea mounts in the eastern Pacific,

00:11:02.63,00:11:06.63 like Cocos, Malpelo and the Galapagos,

00:11:06.63,00:11:10.63 attract silkies in huge groups[br]up to five hundred strong

00:11:14.64,00:11:17.64 Silkies seem to specialize[br]in taking injured fish

00:11:17.64,00:11:21.64 and constantly circle sea mounts on[br]the look out for the chance to do so

00:11:27.65,00:11:31.65 But Silkies are not the only visitors

00:11:33.66,00:11:36.66 Hammerheads gather[br]in some of the largest shark

00:11:36.66,00:11:39.67 shoals to be found anywhere in the ocean

00:11:39.67,00:11:43.66 Sometimes thousands will circle[br]over a single sea mount

00:11:48.67,00:11:51.68 But these sharks are not here for food

00:11:51.68,00:11:55.67 They have come for another reason

00:11:57.68,00:12:01.68 Some of the locals[br]provide a cleaning service

00:12:04.69,00:12:06.69 Following the last El Nino year,

00:12:06.69,00:12:08.69 when a rise in water temperatures

00:12:08.69,00:12:11.70 caused many sharks to suffer[br]from fungal infections,

00:12:11.70,00:12:15.69 the number of hammerheads visiting the sea[br]mounts reached record levels

00:12:26.71,00:12:30.71 Nutrients also well up to the surface[br]along the coasts of the continents

00:12:33.72,00:12:37.72 This is Natal[br]on South Africa's eastern seaboard

00:12:37.72,00:12:41.72 It's June and just off-shore,[br]strange black patches have appeared

00:12:45.73,00:12:49.72 They look like immense oil[br]slicks up to a mile long

00:12:51.74,00:12:54.74 But this is a living slick

00:12:54.74,00:12:57.74 Millions and millions[br]of sardines on a marine

00:12:57.74,00:13:00.75 migration that in terms of sheer biomass

00:13:00.75,00:13:04.74 rivals that of the wildebeest[br]on the grasslands of Africa

00:13:08.75,00:13:10.76 These fish live for most of the time

00:13:10.76,00:13:12.76 in the cold waters south of the Cape,

00:13:12.76,00:13:16.76 but each year the coastal currents reverse

00:13:16.76,00:13:17.76 The warm Agulhas current that

00:13:17.76,00:13:19.77 usually flows down from the north

00:13:19.77,00:13:22.77 has been displaced by cold water[br]coming up from the south

00:13:22.77,00:13:25.77 and that has brought up rich nutrients

00:13:25.77,00:13:29.78 They, in turn,[br]have created a bloom of plankton

00:13:29.78,00:13:33.77 - and the sardines are now feasting on it

00:13:41.79,00:13:42.79 As the sardines travel north,

00:13:42.79,00:13:46.78 a whole caravan of predators follow them

00:13:50.80,00:13:53.80 Thousands of Cape Gannets[br]track the sardines

00:13:53.80,00:13:54.80 They nested off the Cape

00:13:54.80,00:13:57.80 and timed their breeding so that[br]their newly-fledged chicks

00:13:57.80,00:14:01.80 can join them in pursuing the shoals

00:14:07.81,00:14:11.81 Below water, hundreds of sharks[br]have also joined the caravan

00:14:15.82,00:14:17.82 These are Bronze whaler sharks,

00:14:17.82,00:14:21.82 a cold water species that normally[br]lives much further south

00:14:27.83,00:14:30.84 These three-metre sharks[br]cut such great swathes

00:14:30.84,00:14:34.83 through the sardine shoals that their[br]tracks are clearly visible from the air

00:14:36.84,00:14:40.85 Harried by packs of predators and[br]swept in by the action of the waves,

00:14:40.85,00:14:44.84 the sardine shoals are penned[br]close to the shore

00:15:02.87,00:15:06.86 Common dolphin are coming in[br]from the open ocean to join the feast

00:15:21.89,00:15:25.88 There are over a thousand of them[br]in this one school

00:15:32.90,00:15:36.89 When they catch up with the sardines,[br]the action really begins

00:15:40.91,00:15:44.90 Working together,[br]they drive the shoal towards the surface

00:15:53.92,00:15:57.91 It is easier for the dolphins[br]to snatch fish up here

00:16:10.94,00:16:14.93 Now the sardines have no escape

00:16:25.95,00:16:29.94 Thanks to the dolphins, the sardines have[br]come within the diving range of the gannets

00:16:42.97,00:16:45.97 Hundreds of white arrows shoot[br]into the sea,

00:16:45.97,00:16:49.96 leaving long trails[br]of bubbles behind each dive

00:17:00.99,00:17:04.98 Next to join the frenzy are the sharks

00:17:17.00,00:17:20.01 Sharks get very excited[br]when dolphins are around

00:17:20.01,00:17:22.01 That may be because[br]they can feed particularly...

00:17:22.01,00:17:23.01 well once the dolphins have driven

00:17:23.01,00:17:27.00 the sardines into more compact[br]groups near the surface

00:17:31.02,00:17:35.01 As the frenzy continues walls of[br]bubbles drift upwards

00:17:39.02,00:17:43.02 They are being released by the dolphins,[br]working together in teams

00:17:45.03,00:17:49.02 They use the bubbles to corral the[br]sardines into ever tighter groups

00:17:53.04,00:17:57.03 The sardines seldom cross the wall of[br]bubbles and crowd closer together

00:18:02.05,00:18:06.04 Bubble netting in this way enables the[br]dolphins to grab every last trapped sardine

00:18:19.06,00:18:22.07 Just when the feasting[br]seems to be almost over,

00:18:22.07,00:18:26.06 a Bryde whale arrives

00:18:28.07,00:18:31.08 The survivors head on northwards,

00:18:31.08,00:18:35.07 and the caravan of predators follows them

00:18:42.09,00:18:44.09 Nutrients can also be brought up

00:18:44.09,00:18:46.09 - though less predictably

00:18:46.09,00:18:50.08 - - by rough weather

00:18:53.10,00:18:54.10 Particularly near the poles,

00:18:54.10,00:18:57.10 huge storms stir the depths and

00:18:57.10,00:18:59.10 enrich the surface waters and here,

00:18:59.10,00:19:03.10 in the South Atlantic,[br]the seas are the roughest on the planet

00:19:06.11,00:19:09.11 And very rich seas they are too, for here,

00:19:09.11,00:19:11.12 the cold Falklands current from the South

00:19:11.12,00:19:14.12 meets the warm Brazil[br]current from the North

00:19:14.12,00:19:18.11 and at their junction[br]there is food in abundance

00:19:20.13,00:19:23.13 These Black-browed[br]albatross are duck-diving

00:19:23.13,00:19:27.12 for krill that has been driven up[br]to the surface

00:19:30.14,00:19:31.14 Like all albatross,

00:19:31.14,00:19:35.13 Black-brows are wanderers[br]across the face of the open ocean

00:19:50.16,00:19:54.16 A feeding assembly on this scale[br]is a rare sight

00:19:54.16,00:19:55.16 Most of the time,

00:19:55.16,00:19:58.16 the birds of the open sea[br]are widely dispersed

00:19:58.16,00:20:02.17 But these feeding grounds are close[br]to an albatross breeding colony

00:20:02.17,00:20:06.16 - and a very special one

00:20:14.18,00:20:18.17 This is Steeple Jason, a remote island[br]in the far west of the Falklands

00:20:19.18,00:20:23.18 It has the largest albatross[br]colony in the world

00:20:31.20,00:20:33.20 There are almost half a million[br]albatross here

00:20:33.20,00:20:36.20 an astonishing demonstration of

00:20:36.20,00:20:38.20 how fertile the ocean can be

00:20:38.20,00:20:42.20 and how much food it can give even to[br]creatures that do not actually live in it

00:21:09.23,00:21:13.23 Nutrients by themselves are not enough to[br]generate these vast assemblies.

00:21:14.24,00:21:16.24 The heat and light[br]that the sun brings everyday

00:21:16.24,00:21:20.25 is also essential for the growth of[br]the microscopic floating plants

00:21:20.25,00:21:24.24 - the phytoplankton

00:21:27.25,00:21:29.25 And it the phytoplankton

00:21:29.25,00:21:33.25 that is the basis of all life in the ocean

00:21:38.26,00:21:40.27 Every evening,[br]the disappearance of the sun

00:21:40.27,00:21:43.27 below the horizon triggers the largest

00:21:43.27,00:21:47.26 migration of life[br]that takes place on our planet

00:21:54.28,00:21:57.28 One thousand million tones[br]of sea creatures

00:21:57.28,00:22:01.28 ascend from the deep ocean to[br]search for food near the surface

00:22:09.29,00:22:13.30 They graze on the phytoplankton[br]under cover of darkness

00:22:13.30,00:22:16.30 Even so, they are far from safe

00:22:16.30,00:22:18.30 Other marine hunters follow them,

00:22:18.30,00:22:22.30 some travelling up[br]from hundreds of metres below

00:23:20.37,00:23:24.36 At dawn, the whole procession returns[br]to the safety of the dark depths

00:23:32.38,00:23:36.37 The moon too has a great[br]influence on life in the oceans

00:23:38.38,00:23:42.38 Its gravitational pull creates the daily[br]advance and retreat of the tides

00:23:55.40,00:23:58.40 But the moon has[br]more than a daily cycle

00:23:58.40,00:24:02.40 Each month it waxes and wanes[br]as it travels around the earth,

00:24:03.41,00:24:07.40 and this monthly cycle also[br]triggers events in the ocean

00:24:11.42,00:24:15.42 The Pacific Coast of Costa Rica[br]on a very special night

00:24:15.42,00:24:19.41 It just after midnight[br]and the tide is coming in

00:24:23.43,00:24:26.43 The moon is in its last quarter,

00:24:26.43,00:24:30.42 exactly half way between full and new

00:24:32.44,00:24:36.44 For weeks the beach has been empty[br]But that is about to change

00:24:36.44,00:24:40.43 At high tide,[br]turtles start to emerge from the surf

00:24:46.45,00:24:50.44 At first they come in ones and twos,[br]but within a hour,

00:24:51.46,00:24:55.45 they are appearing all along the beach

00:25:00.47,00:25:03.47 They are all female Ridley turtles

00:25:03.47,00:25:05.47 and over the next six days or so

00:25:05.47,00:25:08.47 four hundred thousand[br]will visit this one beach

00:25:08.47,00:25:12.47 to lay their eggs in the sand

00:25:18.48,00:25:22.48 At the peak time, five thousand[br]are coming and going every hour

00:25:23.49,00:25:25.49 The top of the beach gets so crowded that

00:25:25.49,00:25:29.49 they have to clamber over one[br]another to find a bare patch

00:25:29.49,00:25:33.49 where they can dig a nest hole

00:25:36.50,00:25:38.50 A quarter of the world population

00:25:38.50,00:25:41.51 of Ridley turtles come to this one beach

00:25:41.51,00:25:44.51 on a few key nights each year

00:25:44.51,00:25:47.51 The rest of the time, they are widely[br]distributed through the ocean

00:25:47.51,00:25:51.51 searching for food, most[br]-a hundreds of miles away from here

00:25:52.52,00:25:55.52 This mass nesting is called an arribada

00:25:55.52,00:25:57.52 How it is co-ordinated is a mystery

00:25:57.52,00:26:00.53 - but we do know that's arribadas start

00:26:00.53,00:26:04.52 when the moon is either in its first[br]or its last quarter

00:26:12.54,00:26:16.54 Forty million eggs[br]are laid in just a few days

00:26:16.54,00:26:18.54 By synchronising their nesting in this way

00:26:18.54,00:26:21.55 the females ensure that six weeks later

00:26:21.55,00:26:24.55 their hatchlings[br]will emerge in such enormous...

00:26:24.55,00:26:26.55 numbers that predators on the beach

00:26:26.55,00:26:29.55 are overwhelmed[br]and a significant proportion

00:26:29.55,00:26:33.55 of the baby turtles will get past them[br]and make it to the water

00:26:36.56,00:26:38.56 But why do the females[br]use a cue from the moon

00:26:38.56,00:26:41.57 to help in synchronising their nesting?

00:26:41.57,00:26:45.56 Part of the answer to that becomes clear[br]at dawn on the following morning

00:27:07.59,00:27:11.59 The day shift of predators are arriving[br]for their first meals

00:27:17.60,00:27:19.60 Vultures have learnt[br]that the returning tide

00:27:19.60,00:27:23.60 can wash freshly laid eggs out of the sand

00:27:26.61,00:27:28.61 The risk of eggs being exposed by the surf

00:27:28.61,00:27:31.62 may be part of the reason[br]why turtle arribadas

00:27:31.62,00:27:35.61 tend to occur around the last[br]or first quarter of the moon

00:27:39.62,00:27:43.63 It's on such days as this,[br]when the moon is neither full nor new,

00:27:43.63,00:27:47.62 that the tides are weakest and[br]the sea is likely to be calmer

00:28:01.65,00:28:05.65 So at these times,[br]it easier for the female turtles

00:28:05.65,00:28:07.65 to make their way through the surf

00:28:07.65,00:28:08.65 and there less chance of their eggs

00:28:08.65,00:28:12.65 being washed out of the sand[br]and being taken by the vultures

00:28:23.67,00:28:27.67 The moon monthly cycle[br]and its influence on the tides triggers

00:28:27.67,00:28:31.68 many events in the ocean,[br]from the spawning of the corals

00:28:31.68,00:28:35.68 on the Great Barrier reef[br]to the breeding cycles of fish

00:28:35.68,00:28:37.68 But there an even longer rhythm

00:28:37.68,00:28:39.68 that has the most profound effect of all

00:28:39.68,00:28:43.68 - the annual cycle of the sun

00:28:46.69,00:28:48.69 The sun position relative[br]to the earth changes

00:28:48.69,00:28:52.70 through the year and[br]it this that produces the seasons

00:28:52.70,00:28:56.69 In the north, spring comes as the sun[br]begins to rise higher in the sky

00:28:59.70,00:29:01.71 Off the coast of North West America,

00:29:01.71,00:29:05.70 the seas are transformed by the increasing[br]strength of the sunshine

00:29:10.72,00:29:13.72 Here in Alaska the coastal waters turn

00:29:13.72,00:29:17.71 green with a sudden bloom of phytoplankton

00:29:20.73,00:29:23.73 Herring that have spent[br]the winter far out to sea,

00:29:23.73,00:29:26.73 time their return to the shallow waters[br]to coincide with this bloom

00:29:26.73,00:29:29.73 They come in vast numbers and initiate

00:29:29.73,00:29:33.73 one of the most productive[br]food chains in all the oceans

00:29:48.75,00:29:52.76 Humpback whales are at the top[br]of that food chain

00:29:52.76,00:29:56.76 They have spent the winter breeding[br]in the warmer tropical waters off Hawaii

00:29:56.76,00:29:58.76 But there was little food for them there

00:29:58.76,00:30:02.76 This herring bonanza provides the vast[br]majority of their food for the year

00:30:25.79,00:30:28.79 Stellar and Californian sea lions

00:30:28.79,00:30:32.79 also return from the open ocean[br]each year to feast off the herring

00:30:43.81,00:30:46.81 The herring themselves,[br]however, have not come here for food

00:30:46.81,00:30:49.81 They are about to breed

00:30:49.81,00:30:53.81 Nothing deters them as they head[br]for even shallower waters

00:30:55.82,00:30:57.82 Now the waters[br]are so shallow that glaucous

00:30:57.82,00:31:01.82 -winged gulls are able to snatch live fish[br]from just below the surface

00:31:13.84,00:31:15.84 In spite of these attacks and losses,

00:31:15.84,00:31:17.84 the herring swim on until

00:31:17.84,00:31:19.84 they reach the vegetation that the females

00:31:19.84,00:31:23.84 need if they are to lay

00:31:27.85,00:31:31.86 Each female produces[br]around twenty thousand eggs

00:31:31.86,00:31:35.85 - and they every sticky

00:31:37.86,00:31:39.86 The males arrive soon after the females

00:31:39.86,00:31:43.86 have spawned and release their sperm[br]in vast milky clouds

00:31:48.87,00:31:52.88 Soon the excesses[br]of the herrings' sexual spree

00:31:52.88,00:31:56.87 creates a thick, white scum on the surface

00:31:57.88,00:32:01.88 Through the season curds of sperm clog[br]the shores for hundreds of miles,

00:32:02.89,00:32:06.88 from British Columbia in the South[br]all the way to Alaska in the north

00:32:13.90,00:32:15.90 After a few days this gigantic spawning

00:32:15.90,00:32:19.90 comes to an end and the herring head[br]back out to deeper waters,

00:32:19.90,00:32:22.91 leaving behind them[br]fertilised eggs plastered...

00:32:22.91,00:32:26.90 on every rock and strand of vegetation

00:32:37.92,00:32:39.92 They time their spawning[br]so that two weeks later,

00:32:39.92,00:32:41.93 when these eggs start to hatch,

00:32:41.93,00:32:43.93 the annual plankton bloom[br]will have reached

00:32:43.93,00:32:45.93 its height and the new-born fish fry

00:32:45.93,00:32:47.93 will have plenty to eat

00:32:47.93,00:32:50.94 But in the meantime,[br]all these eggs provide food

00:32:50.94,00:32:54.93 for armies of different animals both below[br]and above the surface

00:33:02.95,00:33:06.95 Millions of birds arrive to collect[br]a share of the herring bounty

00:33:06.95,00:33:08.95 Some of it is easily gathered,

00:33:08.95,00:33:12.95 for millions of eggs have been[br]washed up onto the shore

00:33:13.96,00:33:17.95 This encapsulated energy is particularly[br]valuable to migrating birds

00:33:19.96,00:33:21.97 These surfbirds are on their way

00:33:21.97,00:33:24.97 to their breeding grounds in the Arctic

00:33:24.97,00:33:25.97 and they have to come down to refuel

00:33:25.97,00:33:29.96 Stranded herring eggs[br]are just what they need

00:33:31.98,00:33:35.97 Bonaparte gulls collect the eggs[br]just below the surface of the water

00:33:38.98,00:33:42.99 Further out in the bay,[br]huge flocks of ducks have gathered

00:33:42.99,00:33:44.99 They are mostly surf scoters

00:33:44.99,00:33:48.98 - diving ducks - that can feed off[br]the bottom several metres down

00:33:53.00,00:33:55.00 There are such huge quantities of eggs

00:33:55.00,00:33:58.00 that even such a big animal as a bear

00:33:58.00,00:34:02.00 finds it worthwhile to collect them

00:34:04.01,00:34:07.01 The spawning of the herring[br]is a crucial event

00:34:07.01,00:34:10.01 in the lives of many animals[br]all along the coast

00:34:10.01,00:34:13.02 The whole event coincides[br]with the plankton bloom

00:34:13.02,00:34:17.01 and within just three short weeks[br]it all over

00:34:22.03,00:34:26.02 The migratory birds leave[br]to continue their journey north

00:34:34.04,00:34:38.03 They will not come back until[br]the herring also return next year

00:34:44.05,00:34:46.05 As the herring spawning finishes,

00:34:46.05,00:34:50.04 other migrants are starting[br]to arrive just offshore

00:34:52.06,00:34:56.05 Grey whales

00:34:58.06,00:35:00.06 They have followed the sun north

00:35:00.06,00:35:02.07 and they too are seeking the food

00:35:02.07,00:35:06.06 that is generated by[br]the bloom of the phytoplankton

00:35:09.07,00:35:13.08 Krill are feeding off it and these[br]whales are feeding on the krill,

00:35:13.08,00:35:16.08 skimming it from the surface[br]with the filter plates of baleen

00:35:16.08,00:35:20.07 that hang from their upper jaws

00:35:22.09,00:35:24.09 Grey whales make one[br]of the longest migrations

00:35:24.09,00:35:26.09 undertaken by any marine mammal

00:35:26.09,00:35:29.09 - a round trip of 12,000 miles or

00:35:29.09,00:35:31.10 so from their breeding grounds off Mexico

00:35:31.10,00:35:34.10 along the entire coast of North America

00:35:34.10,00:35:38.09 right up to the Arctic ocean

00:35:39.10,00:35:41.11 They travel close to the coast[br]with the males

00:35:41.11,00:35:45.11 and non-breeding females leading the way

00:35:45.11,00:35:48.11 The last to start are the cows[br]that have just given birth

00:35:48.11,00:35:50.11 They have to wait until[br]their new-born calves

00:35:50.11,00:35:54.11 are sufficiently big and strong to tackle[br]such an immense journey

00:35:57.12,00:36:00.12 Their progress is necessarily slow

00:36:00.12,00:36:02.13 The mothers must stay[br]alongside their young

00:36:02.13,00:36:06.12 and even a strong calf can only travel[br]at a couple of knots

00:36:07.13,00:36:09.13 They stick even closer to the shore

00:36:09.13,00:36:13.13 often within just 200 metres

00:36:16.14,00:36:18.14 Killer whales.

00:36:18.14,00:36:22.14 They have learnt that grey whales[br]follow traditional routes

00:36:23.15,00:36:25.15 The killers have no trouble in overtaking

00:36:25.15,00:36:29.14 a calf and its devoted mother

00:36:32.16,00:36:34.16 Normally,[br]they continually call to one another,

00:36:34.16,00:36:37.16 but now they have fallen silent

00:36:37.16,00:36:41.15 The mother grey whale and her calf[br]have no idea that they have been targeted

00:37:03.19,00:37:07.19 Catching up with the grey whales[br]is the easy part for the killers

00:37:07.19,00:37:09.19 They have to be cautious[br]for they are only...

00:37:09.19,00:37:13.19 about half the size[br]of the grey whale mother

00:37:15.20,00:37:19.19 She can inflict real damage with her tail

00:37:27.21,00:37:31.22 But the killers are not after her[br]They are after her calf

00:37:31.22,00:37:33.22 As long as the mother[br]can keep it on the move,

00:37:33.22,00:37:37.21 it will be safe and[br]she does her best to hurry it along

00:37:40.22,00:37:42.23 At first the killers[br]avoid getting too close...

00:37:42.23,00:37:45.23 to the mother but just keep pace alongside

00:37:45.23,00:37:46.23 They know that the calf,

00:37:46.23,00:37:50.22 going at this speed, will eventually tire

00:37:59.24,00:38:02.25 After three hours[br]of being harried in this way

00:38:02.25,00:38:05.25 the calf becomes too exhausted[br]to swim any further

00:38:05.25,00:38:08.25 The mother has to stop

00:38:08.25,00:38:11.26 This is the moment the killers[br]have been waiting for

00:38:11.26,00:38:15.25 They start to try and force themselves[br]between mother and calf

00:38:36.28,00:38:38.28 A calf, separated from its mother,

00:38:38.28,00:38:40.28 will not be able to defend itself

00:38:40.28,00:38:42.29 Time and again the black fins

00:38:42.29,00:38:46.28 of the killers appear between[br]the mottled backs of the grey whales

00:38:57.30,00:38:59.30 At last the killers succeed

00:38:59.30,00:39:03.30 And now that they've got the calf[br]on its own, they change their tactics

00:39:04.31,00:39:08.30 They leap right on to the calf[br]and try to push it under

00:39:19.32,00:39:23.32 They are trying to drown it

00:39:30.33,00:39:34.33 The calf snatches a desperate breath

00:39:46.35,00:39:49.35 The mother becomes increasingly agitated

00:39:49.35,00:39:51.36 Frantically,[br]she tries to push her calf back

00:39:51.36,00:39:55.35 to the surface so that it can breathe

00:39:58.36,00:40:02.36 But now it is so exhausted that it has[br]to be supported by its mother's body

00:40:20.38,00:40:21.39 The killers won't give up

00:40:21.39,00:40:25.38 Like a pack of wolves,[br]they take turns in harassing the whales

00:40:47.41,00:40:51.40 Now the whole pod is involved

00:41:00.42,00:41:04.42 One of them takes a bite

00:41:14.44,00:41:18.44 Soon the sea is reddened[br]with the calf's blood

00:41:18.44,00:41:22.44 and the killers close in for the final act

00:41:42.47,00:41:46.46 The calf is dead

00:41:48.47,00:41:52.47 After a six-hour hunt, the killer whales[br]have finally won their prize

00:41:59.48,00:42:03.48 The mother, bereft, has to continue[br]her migration north on her own

00:42:09.49,00:42:12.50 She leaves behind the carcass[br]of a calf that

00:42:12.50,00:42:15.50 she cherished[br]for thirteen months in her womb

00:42:15.50,00:42:19.49 for which she delayed[br]her own journey to find food

00:42:22.51,00:42:26.50 The pod of fifteen killer whales spent[br]over six hours trying to kill this calf

00:42:27.51,00:42:29.51 But now, having succeeded,

00:42:29.51,00:42:33.51 they have eaten nothing[br]more than its lower jaw and its tongue

00:42:41.53,00:42:45.52 Valuable food like this will not[br]go to waste in the ocean

00:42:46.53,00:42:50.52 Before long the carcass will sink[br]to the very bottom of this deep sea

00:42:51.54,00:42:55.53 But even there,[br]its flesh will not be wasted

00:42:57.54,00:43:01.55 Over a mile down in the[br]total darkness of the deep ocean

00:43:01.55,00:43:05.55 - the body of another grey whale,[br]a thirty ton adult

00:43:05.55,00:43:09.54 It settled here only a few weeks ago

00:43:10.55,00:43:14.55 Already,[br]it has attracted hundreds of hagfish

00:43:20.56,00:43:22.57 These scavengers, over half a metre long

00:43:22.57,00:43:26.57 and as thick as your arm,[br]are only found in the deep sea

00:43:26.57,00:43:29.57 They have been attracted[br]by the faint whiff of

00:43:29.57,00:43:33.57 decay suffusing through the water[br]for miles around

00:43:37.58,00:43:39.58 With their heads buried[br]in the whale's flesh,

00:43:39.58,00:43:43.58 they breathe through gill openings[br]along the sides of their bodies

00:43:44.59,00:43:46.59 They're very primitive creatures

00:43:46.59,00:43:49.59 - not even true fish, for they lack jaws.

00:43:49.59,00:43:52.60 - They feed, not by biting, but by

00:43:52.60,00:43:56.59 rasping off flesh[br]with two rows of horny teeth

00:43:57.60,00:43:58.60 In just a few hours,

00:43:58.60,00:44:02.60 a hagfish can eat several times[br]its own weight of rotting flesh

00:44:07.61,00:44:11.60 Next to arrive - a sleeper shark

00:44:16.62,00:44:19.62 It moves so slowly to conserve energy

00:44:19.62,00:44:21.63 - an important strategy for so large

00:44:21.63,00:44:25.62 an animal surviving in such a poor habitat

00:44:31.64,00:44:34.64 Sleeper sharks live over a mile down

00:44:34.64,00:44:38.63 and grow to over seven metres long

00:44:39.64,00:44:42.65 They can go for months without food,

00:44:42.65,00:44:46.65 slowly cruising along the bottom,[br]waiting for rare bonanzas,

00:44:46.65,00:44:50.64 such as this one, to arrive from above

00:44:56.66,00:44:59.66 A whole range of different[br]deep-sea scavengers

00:44:59.66,00:45:02.67 will feast on this carcass for a long time

00:45:02.67,00:45:06.66 before all its nutriment has been consumed

00:45:07.67,00:45:11.66 Eighteen months later, all that is left[br]is a perfect skeleton, stripped bare

00:45:16.68,00:45:17.68 The sun's energy that was captured

00:45:17.68,00:45:20.68 and turned into living tissue[br]by the floating

00:45:20.68,00:45:22.69 phytoplankton has been transferred from

00:45:22.69,00:45:24.69 one link to another in the food chain

00:45:24.69,00:45:27.69 and has ended up as far away from the sun

00:45:27.69,00:45:29.69 as it is possible to be on this planet

00:45:29.69,00:45:32.70 - at the bottom of the deep sea

00:45:32.70,00:45:36.69 But some energy also returns from the deep

00:45:42.71,00:45:46.70 Millions of opalescent squid are[br]on their way to the shallows

00:45:48.71,00:45:49.71 They have come up here to mate

00:45:49.71,00:45:53.71 As the males grab the females,[br]their tentacles flush red

00:45:56.72,00:45:57.72 For most of the year these squid

00:45:57.72,00:46:00.72 live at a depth of around 500 metres

00:46:00.72,00:46:04.73 They only come together in these great[br]breeding schools for a few weeks

00:46:04.73,00:46:08.72 Just one school was estimated to contain[br]animals that weigh around 4000 tonnes

00:46:22.75,00:46:24.75 Wave after wave rise from the depths

00:46:24.75,00:46:26.75 and soon the seabed[br]in the shallows is strewn

00:46:26.75,00:46:30.74 with dense patches of egg capsules[br]several metres across

00:46:36.76,00:46:39.76 As each female adds[br]another capsule to the pile

00:46:39.76,00:46:43.76 the males fight to fertilise its contents

00:46:58.78,00:47:00.78 The squid make their huge journey

00:47:00.78,00:47:02.79 into the shallows because their eggs

00:47:02.79,00:47:05.79 will develop faster[br]in the warmer water here

00:47:05.79,00:47:07.79 and when the young emerge,[br]they will find more

00:47:07.79,00:47:11.78 food more easily than[br]they would in the ocean depths

00:47:16.80,00:47:20.79 Dawn the next morning and the seabed for[br]miles around is covered in egg capsules.

00:47:23.81,00:47:25.81 The squid themselves have all gone

00:47:25.81,00:47:29.80 Many will have died, but some will have[br]returned to their home in the deep

00:47:30.81,00:47:32.82 They will not return[br]to the light of the sun

00:47:32.82,00:47:36.81 until the next time they are driven up[br]by the urge to spawn