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Most of the earth is covered by water.
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In fact, two-thirds of it is.
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And it's only in this generation
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that we have been able to move about it
with any degree of freedom as I am doing now.
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So perhaps it is not surprising
that still most of this vast domain
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is still unexplored.
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And in the geographical sense,
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the surface of the sea, the floor of the sea,
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is even more varied
than the surface of the land.
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To see just how varied it is,
let's take an imaginary journey across the Pacific
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starting in the west where the ocean is deeper
than anywhere else on the globe:
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The Mariana trench.
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The bottom of this immense valley seven miles
below the surface is grooved by deep faults.
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If Mount Everest rose from the bottom,
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its summit would still be
beneath 7,000 feet of water.
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Down at the very bottom, the water pressure
is some seven tons per square inch,
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the temperature is close to freezing,
and it's pitch-dark,
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for it is far beyond the reach of sunlight.
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As we climb up out of the trench,
we move onto a plain covered with reddish mud.
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A few hills rise from it, but there are still
some 20,000 feet of water above us.
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Travel eastwards over these plains
for 1,000 miles,
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and we reach a range of fantastic mountains.
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Their summits are covered
by a white deposit like snow,
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composed of the limestone skeletons
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of microscopic organisms
that have drifted down from the surface.
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Before they reach the lower slopes, the water
pressure becomes so great they dissolve.
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Currents sweeping up from the south
pile the sand into dunes 150 feet high
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which advance slowly across the sea floor
as dunes do in a desert on land.
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In places, the sand is littered with metallic
lumps, some as big as cannon balls:
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Manganese that under these pressures
has precipitated out from the salty water.
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After a journey of 4,000 miles,
we reach the biggest mountains of all.
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These are the flanks
of the great volcanic islands of Hawaii.
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Their sides are steeper
than any mountain on land
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for they are never eroded by frost
or by rivers armed with gravel.
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They rise from the sea floor
15,000 feet to the surface
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and continue for an almost equal height above it,
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so they can truly be reckoned
the highest mountains in the world.
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00:05:06,472 --> 00:05:08,770
As we climb up their sides towards the surface,
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we return once more to light and to abundant life.
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00:05:20,453 --> 00:05:24,787
Life began in sunlit waters like these
some 3,000 million years ago,
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00:05:25,124 --> 00:05:28,218
and creatures very similar
to those ancient primeval organisms
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still flourish in shallow seas all over the world.
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Feather stars like these waved their tentacles
long before any fish appeared,
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at a time when the land
was still bare of life of any kind.
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00:05:50,883 --> 00:05:54,114
Horseshoe crabs come from
an equally antique stock.
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Fossils have been found in rocks
600 million years old.
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Most of their relatives have died out.
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00:06:00,660 --> 00:06:05,597
These are the lonely survivors
of a widespread and successful group.
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00:06:24,317 --> 00:06:27,650
Even older,
indeed among the first of all living things,
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microscopic plants encased in shells of limestone.
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They use sunshine to build, from simple
chemicals in the sea water, their own tissue.
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00:06:36,896 --> 00:06:40,229
This act of photosynthesis,
transforming mineral into vegetable,
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is the basis of all life in the sea.
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00:06:48,541 --> 00:06:50,236
A myriad of creatures feed on them.
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Some are tiny animals, scarcely bigger
than the plants that they waft into their mouths.
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00:07:03,055 --> 00:07:06,718
This floating community of plants and animals
is the plankton.
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Its members move endlessly
through the blue seas.
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Many are fragile constructions ofjelly
that would collapse without the support of water.
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00:07:26,245 --> 00:07:29,339
Some are colonial, several feet long.
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00:07:38,191 --> 00:07:41,888
They call this Venus's girdle. It's two feet acros
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00:07:42,094 --> 00:07:45,222
Light catches in the beating hairs
that ripple over its body
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as it moves slowly through the water.
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00:07:51,237 --> 00:07:54,638
The animals of the plankton,
all those that can't photosynthesise,
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sweep up the tiny plants and other edible particle
in many different ways.
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00:08:02,715 --> 00:08:08,017
This one extends a forest of long tentacles
in which smaller organisms get entangled.
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00:08:10,323 --> 00:08:13,918
This, transparent as glass, trails stinging thread
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00:08:14,093 --> 00:08:17,028
and pulls them in
whenever they catch something.
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00:08:31,377 --> 00:08:33,811
Worms actively pursue their prey.
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00:08:42,255 --> 00:08:46,817
Creatures from many families of animals
have representatives in this community.
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00:08:47,059 --> 00:08:50,722
Some are permanent members,
some only temporary,
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joining it when they are young larvae
and drifting great distances
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before they grow up, change shape
and settle down to a more static life.
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00:08:59,305 --> 00:09:04,242
But all are ultimately dependent
on the tiny microscopic plants.
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00:09:14,654 --> 00:09:17,885
There is another way in which
the drifting particles of food can be gathered.
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Instead of moving with the current,
you stay fixed to the rocks
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00:09:22,094 --> 00:09:25,063
and allow the currents to bring food to you.
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That is the technique
used by anemones and many other creatures.
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00:09:31,804 --> 00:09:36,935
As the water sweeps by, the particles it carries
stick to the waving tentacles.
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00:09:48,254 --> 00:09:52,850
All kinds of creatures live in this fashion.
This is a sea cucumber.
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00:09:59,532 --> 00:10:02,023
And this, a basket star.
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00:10:13,512 --> 00:10:16,948
The water brings not only food but vital oxygen.
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00:10:17,149 --> 00:10:19,811
If it doesn't bring it fast enough,
it can be speeded
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00:10:19,986 --> 00:10:22,716
by pulsing as these coral polyps are doing.
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00:10:28,327 --> 00:10:32,821
It's not only simple creatures
like anemones and corals that filter currents.
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00:10:33,099 --> 00:10:36,557
Other more complex animals
have also taken to doing so.
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00:10:36,769 --> 00:10:40,466
This is a remote relative of the shrimps
that has settled down on its back,
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00:10:40,640 --> 00:10:45,805
grown a protective shell
and fishes for the passing particles with its feet
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It's a barnacle.
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00:10:59,992 --> 00:11:03,359
Some crabs also rely on the currents
to bring them meals,
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00:11:03,529 --> 00:11:06,794
and pluck them from the water with tiny pincers.
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00:11:11,704 --> 00:11:17,506
But the biggest of all filter-feeders propel
themselves gently through the surface waters.
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A manta ray, 18 feet across.
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It often feeds at night
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when dense swarms of the plankton
move up towards the surface.
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The water is channelled into its mouth
by the blades on the sides of its head,
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00:11:37,129 --> 00:11:41,259
then passes through filters
in the slits in the sides of its throat.
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00:11:48,407 --> 00:11:52,969
The basking shark
gathers the same sort of food in a similar way.
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00:11:53,512 --> 00:11:58,916
It grows even bigger than the manta:
40 feet long and four tons in weight.
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Idling through the water,
it filters over 1,000 tons of water every hour.
100
00:12:18,637 --> 00:12:24,132
And even bigger still, in fact,
the biggest of all fish: The whale shark.
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This mountain of a creature
can be up to 50 feet long.
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Other, more normal-sized fish
live on and around it. Some collect its refuse.
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Others pick off morsels that get stuck
in its tiny teeth in a mouth six feet wide.
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00:13:04,784 --> 00:13:10,245
It's an astonishing proof of how sustaining
and how abundant the plankton must be.
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00:13:21,467 --> 00:13:26,302
But of course, not all sharks live on plankton
or are quite so amiable.
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00:13:29,141 --> 00:13:32,702
These are grey reef sharks, about six feet long.
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00:13:44,657 --> 00:13:49,924
It's some consolation to know that those sharks
don't normally attack human beings.
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00:13:50,262 --> 00:13:55,495
Their prey is usually small fish or predators.
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00:13:56,168 --> 00:14:03,939
And indeed, when one looks at them, it is not
so much their danger that comes into your mind
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00:14:04,109 --> 00:14:06,043
as their extraordinary beauty.
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00:14:06,679 --> 00:14:09,580
They are so perfectly streamlined,
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00:14:09,748 --> 00:14:12,911
every curve of their body, every curve of their fi
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precisely matching the shape that is needed
to glide through the water with the least struggle
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00:14:20,926 --> 00:14:22,416
Most beautiful things.
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Sharks belong to a very ancient family that
evolved this shape some 400 million years ago.
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00:14:30,102 --> 00:14:34,038
But soon after they appeared,
another group of fish established itself.
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00:14:36,308 --> 00:14:39,709
These have skeletons of bone,
not gristle as the sharks have,
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and they have two swimming aids
that the sharks lack:
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Swim bladders that give them buoyancy
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and paired fins that can twist in all directions
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and so give them
great manoeuvrability in the water.
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00:14:51,924 --> 00:14:56,623
These bony fish are the ones
which today dominate the seas.
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Among them are the most powerful
of all hunters in the sea: The tuna.
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When hunting,
they can swim faster than any other fish.
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Some say nearly 70 miles an hour,
faster even than a cheetah can run on land.
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But the fish's dominance of the sea
didn't go unchallenged.
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Ten million years ago, warm-blooded creatures
from the land invaded the sea, mammals,
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and they became equally streamlined.
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00:16:19,378 --> 00:16:21,972
Dolphins and killer whales are descended
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from four-footed, land-living,
air-breathing mammals that were flesh-eaters.
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In the sea, they lost their limbs
but not their taste for meat, nor their teeth.
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00:16:32,324 --> 00:16:36,351
Indeed, one of the family that lives
only in the ice-strewn waters of the Arctic
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has grown one of its teeth
to an extraordinary length.
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00:16:49,975 --> 00:16:52,671
These are narwhals, and they are all males,
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00:16:52,845 --> 00:16:56,804
for only the male produces the tusk,
up to nine feet long.
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These without tusks are females, one with a calf.
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And these are young males.
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No one knows for certain
what purpose the tusk serves,
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00:17:16,869 --> 00:17:19,394
but it seems likely that it is used in courtship.
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That is confirmed by the fact
that very rarely indeed
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males have been glimpsed,
as here, fencing with one another.
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The best view that most of us can get
for most of the time of most kinds of whales
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is a brief glimpse as the animal
comes to the surface to snatch a breath,
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00:18:04,983 --> 00:18:10,319
but that's not the case with the beluga,
these beautiful white whales.
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Up here in the Canadian Arctic,
they come during those brief weeks
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when the ice goes away from these shores,
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and assemble in vast numbers in this bay.
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There are hundreds,
sometimes as many as a thousand.
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00:18:34,113 --> 00:18:38,812
We don't really know why they come here,
nor what they do now that they are here.
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00:18:39,051 --> 00:18:42,782
Maybe there is some kind of specially
attractive food in these shallow waters,
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for they seem to stir up
the gravelly bottom of the bay.
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Perhaps there is valuable food
for youngsters or nursing mothers,
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00:18:52,564 --> 00:18:56,295
for many that come are females
with babies a few months old,
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swimming skilfully in their mother's slipstream.
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Whatever it is that they do here,
they seem to be enjoying themselves hugely.
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00:19:09,548 --> 00:19:12,949
And they haven't lost their mammalian habit
of communicating by sound.
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So vocal are they
that they are sometimes called sea canaries.
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00:19:25,664 --> 00:19:29,031
The most recent family to colonise the sea,
also mammals,
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00:19:29,201 --> 00:19:31,635
were descended from bear-like creatures.
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00:19:32,437 --> 00:19:34,302
The walrus and its cousin the seals
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are not so fully adapted to life in the sea as
the whales, but they haven't been there so long.
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They haven't lost their feet as the whales have,
nor do they spend all their lives in the water.
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They come ashore to give birth
and they often haul themselves out to rest.
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Nonetheless, they are superb swimmers.
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00:20:12,044 --> 00:20:16,845
So, in the 3,000 million years
since living organisms first appeared in the sea,
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the oceans have acquired
a population of immense diversity,
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00:20:20,953 --> 00:20:23,751
from single-celled microscopic plants
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00:20:23,922 --> 00:20:27,380
to advanced and complex
highly intelligent mammals.
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00:20:27,859 --> 00:20:32,228
Indeed, there are more different groups
of animals living in the sea than there are on lan
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00:20:35,701 --> 00:20:38,864
The oceans were the birthplace
and the nursery of life,
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and they are still its main residence.
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00:21:35,961 --> 00:21:37,895
But the sea is not uniform.
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Just as land has different,
specialised environments
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inhabited by creatures that occur nowhere else,
so does the sea.
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00:21:46,138 --> 00:21:51,804
The coral lagoon is a world of its own.
Corals are very demanding in their requirements.
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They must have good light,
clear, unpolluted water and warmth,
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00:21:56,248 --> 00:21:59,775
and they find this in the tropics,
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particularly around the small islands
that are the summits of submarine mountains.
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00:22:04,389 --> 00:22:08,189
There, they flourish so well that they grow
outwards into the clear blue water,
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00:22:08,360 --> 00:22:13,423
building on top of their own skeletons
to form wide, shallow lagoons.
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00:22:18,203 --> 00:22:22,469
The variety of corals is immense.
Some are soft and rubbery,
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00:22:22,641 --> 00:22:27,601
others are hard and slightly flexible, like a horn
But most are stony.
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00:22:28,380 --> 00:22:33,943
The organisms that build these structures,
ton upon ton, occupy only the outer skin.
184
00:22:34,319 --> 00:22:38,983
The rest is dead.
As they develop, the little organisms branch,
185
00:22:39,157 --> 00:22:42,149
and the particular way they do so
determines the shape of the colony,
186
00:22:42,327 --> 00:22:48,129
forming antlers and organ pipes,
whips and fans, vases and buttons.
187
00:23:02,214 --> 00:23:06,548
If the jungle is the place on land
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where there are the greatest number
and the greatest variety of life,
189
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then this, the coral reef,
is surely the jungle of the sea.
190
00:23:20,832 --> 00:23:22,595
The number, the variety,
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00:23:22,768 --> 00:23:30,174
the sheer beauty of all these myriad fish,
corals and anemones, is quite breathtaking.
192
00:23:32,911 --> 00:23:39,612
Of course, the tiny anemone-like creatures
that build these fans and fronds of coral
193
00:23:39,785 --> 00:23:41,252
are themselves animals.
194
00:23:42,053 --> 00:23:50,961
But within their tissues,
there are tiny granules which are algae, plants,
195
00:23:51,329 --> 00:23:58,997
and it's they that harness the sunshine
and use it to build living tissue.
196
00:23:59,538 --> 00:24:03,201
And onto these plates and branches of coral
197
00:24:03,375 --> 00:24:06,970
come a wide variety of creatures to browse.
198
00:24:08,880 --> 00:24:11,542
Some, like the parrotfish, bite off chunks.
199
00:24:11,783 --> 00:24:16,311
Others pick off little organisms and particles
with the utmost delicacy.
200
00:24:34,239 --> 00:24:36,867
The tides, surging in and out of the lagoon,
201
00:24:37,042 --> 00:24:41,843
bring in regular supplies
of fresh oxygenated water and fresh food.
202
00:24:42,147 --> 00:24:47,608
Angler fish sit in the current waiting patiently,
like all fishermen, for whatever turns up.
203
00:24:47,886 --> 00:24:52,414
Even such specialised fish as these
exist on the reef in several different versions.
204
00:24:52,624 --> 00:24:57,152
There's this lemon-yellow one that angles
with a movable spine on its forehead.
205
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Little reef fish find it an irresistible bait.
206
00:25:16,047 --> 00:25:19,813
More prey to be angled for by the decoy fish.
207
00:25:28,293 --> 00:25:33,458
A dorsal fin patterned with a false eye and mouth
so that it looks like a little fish
208
00:25:33,632 --> 00:25:38,433
and may attract other small fish
or possibly predatory ones.
209
00:25:39,738 --> 00:25:42,901
This one is the wrong way round.
Its spines would stick in the mouth.
210
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That's better.
211
00:25:49,814 --> 00:25:52,476
One of the fastest actions in the animal world.
212
00:25:55,887 --> 00:25:58,981
And the angler,
perhaps to prevent a second fish arriving
213
00:25:59,157 --> 00:26:00,920
before it has digested the first,
214
00:26:01,092 --> 00:26:04,084
changes colour so that the lure vanishes.
215
00:26:10,702 --> 00:26:13,728
In the reef, there are many species
with many ways of life.
216
00:26:14,005 --> 00:26:16,166
Just take the crustaceans, for example.
217
00:26:16,508 --> 00:26:18,703
Hermit crabs live by scavenging.
218
00:26:18,944 --> 00:26:23,040
Often, they share the shells they have
commandeered as a home with anemones.
219
00:26:24,583 --> 00:26:27,746
The anemones benefit
by picking up bits of the crab's meal
220
00:26:27,919 --> 00:26:32,288
and give the crab in return a certain protection
with their stinging tentacles.
221
00:26:34,292 --> 00:26:37,693
This crab actually uses
a particular kind of anemone as a weapon,
222
00:26:37,963 --> 00:26:40,363
wearing one on each claw like boxing gloves.
223
00:26:43,068 --> 00:26:45,866
This one tries to put on a sponge
like an overcoat.
224
00:26:46,104 --> 00:26:50,097
It's rather overdoing things,
for the brown jersey it's wearing
225
00:26:50,275 --> 00:26:52,937
is also a sponge, and a well-established one.
226
00:26:53,278 --> 00:26:55,269
But the arrangement will suit both parties.
227
00:26:55,480 --> 00:26:59,849
The crab gets the camouflage and the sponge
may benefit from the crab's crumbs.
228
00:27:06,458 --> 00:27:08,824
Crabs and their relations,
the lobsters and shrimps,
229
00:27:08,994 --> 00:27:11,224
are found from top to bottom of the reef.
230
00:27:11,630 --> 00:27:15,726
Big ones like this lobster
prowl openly through the coral branches.
231
00:27:21,706 --> 00:27:26,268
Little ones like the mantis shrimp are rather
more cautious and build themselves tunnels.
232
00:27:36,254 --> 00:27:38,814
If the coral reef is the equivalent of the jungle,
233
00:27:38,990 --> 00:27:44,360
maybe these waving beds of kelp in the cold
Atlantic waters off the coast of Norway
234
00:27:44,529 --> 00:27:47,862
are like the dark evergreen forests of the north,
235
00:27:48,133 --> 00:27:53,400
bitterly cold, dense and uniform,
and swept by raging gales.
236
00:28:13,591 --> 00:28:17,186
Bleak though the kelp forest may seem,
there are riches here,
237
00:28:17,362 --> 00:28:19,330
and eider duck know it.
238
00:28:31,543 --> 00:28:35,570
The eiders settle in flocks
on the surface of the water above the kelp forest,
239
00:28:35,747 --> 00:28:40,377
and they are almost as adept in flying
through the water as they are through the air.
240
00:28:58,069 --> 00:29:01,061
This is what they seek: Mussels.
241
00:29:10,548 --> 00:29:15,178
Eiders are true creatures of the sea,
seldom, if ever, visiting fresh water.
242
00:29:15,353 --> 00:29:20,017
They prefer to fish for mussels
on an ebb tide when the water is low,
243
00:29:20,191 --> 00:29:24,025
but they can stay below water
for a minute or more,
244
00:29:24,195 --> 00:29:27,460
and dive down to 50 feet below the surface.
245
00:29:37,442 --> 00:29:41,708
The streaming current causes great problems
to the fish of the kelp forest.
246
00:29:41,946 --> 00:29:44,506
Simply maintaining a position there is a struggle.
247
00:29:44,682 --> 00:29:48,743
The lumpsucker does it
with modified fins on its underside,
248
00:29:49,020 --> 00:29:54,219
and gets such a firm grip
that it is extremely difficult to pull it off.
249
00:29:54,392 --> 00:29:56,792
Its young develop suckers at a very early age
250
00:29:56,961 --> 00:30:01,921
and sometimes fix themselves to their father,
who ferries them off to deeper waters.
251
00:30:05,103 --> 00:30:07,970
Kelp grows in coastal waters all round the world,
252
00:30:08,139 --> 00:30:10,903
and in the seaweed forests
of southern Australia
253
00:30:11,075 --> 00:30:15,068
lives one of the most
extravagantly camouflaged of all fish.
254
00:30:24,589 --> 00:30:27,387
Other fish appear to be completely deceived.
255
00:30:27,659 --> 00:30:30,025
This small one, itself with a false eye
256
00:30:30,195 --> 00:30:32,823
so that it is difficult to tell
whether it is coming or going,
257
00:30:32,997 --> 00:30:38,799
lives in these green leafy tatters
as though they were real plants, but they're not.
258
00:30:39,037 --> 00:30:43,565
They're all part of the elaborate costume
of the leafy seadragon.
259
00:31:14,405 --> 00:31:16,635
The dragon is a kind of a seahorse,
260
00:31:16,808 --> 00:31:21,905
as you can see if you disentangle
its main body from its extraordinary outgrowths.
261
00:31:22,247 --> 00:31:27,583
Like its relatives, it has a tiny mouth
with which it picks up small shrimps
262
00:31:27,752 --> 00:31:32,121
that ill-advisedly take shelter
in what appears to be floating weed.
263
00:32:06,057 --> 00:32:09,618
As well as its forests, the sea has its deserts.
264
00:32:09,961 --> 00:32:15,695
Over vast areas of the ocean floor,
there is nothing but shifting wastes of sand.
265
00:32:17,435 --> 00:32:21,633
It seems as lifeless as a desert on land
in the heat of the day.
266
00:32:25,510 --> 00:32:30,072
An occasional fish wanders
over the rippled surface as though lost.
267
00:32:32,717 --> 00:32:35,652
Here and there,
a sea urchin levers itself along,
268
00:32:35,820 --> 00:32:40,223
extracting what nutriment it can find
from particles within the sand.
269
00:32:45,430 --> 00:32:50,732
The goatfish looks for the same sort of thing,
using sensitive barbels on its chin.
270
00:32:57,508 --> 00:33:01,774
To build a home or a shelter in sand
demands special techniques.
271
00:33:02,413 --> 00:33:05,905
Garden eels cement grains
together with mucus to form a tube
272
00:33:06,084 --> 00:33:10,487
in which they cling with their tails
while collecting plankton with their mouths.
273
00:33:12,323 --> 00:33:16,054
Bulldozer shrimps and a goby
cooperate to build a shared tunnel,
274
00:33:16,227 --> 00:33:18,752
using coral rubble to prop up the roof.
275
00:33:39,317 --> 00:33:43,253
The bladefish can improvise a shelter
on the spur of the moment.
276
00:33:51,896 --> 00:33:54,091
There are two very different reasons
for hiding.
277
00:33:54,298 --> 00:33:57,665
The bladefish does it to get out of trouble.
278
00:34:01,305 --> 00:34:03,273
This little cuttlefish does it...
279
00:34:05,543 --> 00:34:07,670
...in order to cause trouble.
280
00:34:21,893 --> 00:34:23,918
The prey is a shrimp.
281
00:34:50,988 --> 00:34:54,754
And the cuttlefish has the shrimp
firmly in its tentacles.
282
00:35:08,840 --> 00:35:12,970
The floating pastures of plankton
on which so many ocean-going fish depend
283
00:35:13,144 --> 00:35:16,910
must live in the surface waters
within the reach of sunshine.
284
00:35:17,381 --> 00:35:22,341
The coral lagoon and the kelp forests
only flourish where good light reaches the bottom.
285
00:35:22,820 --> 00:35:26,187
But light can't penetrate much beyond 350 feet,
286
00:35:26,357 --> 00:35:30,316
and most of the ocean floor
lies far deeper that that.
287
00:35:38,903 --> 00:35:42,930
Even quite near the surface
you have to take your own light with you.
288
00:35:53,784 --> 00:35:56,014
Fish, too, carry lights.
289
00:36:01,592 --> 00:36:04,652
The flashlight fish use theirs to find their food
290
00:36:04,829 --> 00:36:09,857
and to maintain contact
like other species in deeper water.
291
00:36:11,302 --> 00:36:15,932
Their batteries are little colonies of bacteria
living in a pouch beneath the fish's eye
292
00:36:16,107 --> 00:36:19,201
that give off light
as a by-product of their chemistry,
293
00:36:19,377 --> 00:36:24,679
and the fish turns its lights off and on
by raising and lowering a flap of skin.
294
00:36:29,387 --> 00:36:34,586
At greater depths, giant amphipods,
primitive relatives of the horseshoe crabs,
295
00:36:34,759 --> 00:36:36,317
plod along the bottom.
296
00:36:37,128 --> 00:36:40,325
Very little is known
about these strange creatures.
297
00:37:02,553 --> 00:37:05,920
Even at 3,000 feet down there is life.
298
00:37:06,290 --> 00:37:10,659
Almost all the creatures here
feed on dead bodies that fall from above.
299
00:37:10,895 --> 00:37:13,693
The eel-like hagfish, which have no jaws,
300
00:37:13,864 --> 00:37:17,197
knot themselves against the carcass
to get a better hold.
301
00:37:31,215 --> 00:37:35,948
Bigger fish grip with their teeth and spin,
tearing off strips of the flesh.
302
00:37:38,456 --> 00:37:40,822
The smaller particles
drifting down from the surface
303
00:37:40,992 --> 00:37:44,257
are collected by deep-sea stars and smaller fish.
304
00:37:44,495 --> 00:37:48,955
It is here that all the nutrients
produced by decay finally collect as ooze.
305
00:37:49,300 --> 00:37:53,396
The very deepest parts of the ocean
lie below the paths of currents,
306
00:37:53,571 --> 00:37:57,667
so the water is not only black and cold
but almost still.
307
00:38:00,077 --> 00:38:04,946
The weird tripod fish
perches on its extended fins and its tail.
308
00:38:10,688 --> 00:38:16,092
Even in the deepest place of all, the Mariana
trench, seven miles down, there is life.
309
00:38:16,961 --> 00:38:19,759
Shrimps are slowly picking clean
the skeleton of a fish
310
00:38:19,930 --> 00:38:24,333
that may have taken months
to drift down to these still depths.
311
00:38:30,875 --> 00:38:34,504
But at the surface of the sea,
the water is never still.
312
00:38:47,325 --> 00:38:51,728
Storms whip it up into great waves
which may travel for hundreds of miles
313
00:38:51,896 --> 00:38:54,922
before, eventually, they crash into the coasts.
314
00:39:05,509 --> 00:39:08,034
The water in these waves doesn't travel far,
315
00:39:08,212 --> 00:39:12,979
but circulates more or less in the same place
while the wave itself moves on.
316
00:39:13,951 --> 00:39:17,387
But that circulation is of crucial importance
to the creatures of the sea,
317
00:39:17,555 --> 00:39:23,687
for it is this that allows the waters of the sea
to absorb the vital oxygen from the air above.
318
00:40:03,667 --> 00:40:06,568
But deep currents do move through the oceans.
319
00:40:06,937 --> 00:40:08,928
They are created by the spin of the earth
320
00:40:09,106 --> 00:40:12,098
which gives the waters at the equator
a westward drift,
321
00:40:12,276 --> 00:40:18,010
and by the sun which warms these equatorial
waters and sends them away to the poles.
322
00:40:18,649 --> 00:40:24,383
This produces vast ocean-wide eddies
that replicate the whirlpools of tidal races,
323
00:40:24,555 --> 00:40:28,582
but do so on a scale
that is thousands of miles across.
324
00:40:33,631 --> 00:40:36,725
In the Pacific, the equatorial current divides,
325
00:40:36,901 --> 00:40:40,132
and in the south it flows down
as far as New Zealand.
326
00:40:42,873 --> 00:40:46,070
In the Indian Ocean,
the southern system is almost circular.
327
00:40:46,310 --> 00:40:49,302
The northern has to swirl
around the great triangle of India.
328
00:40:52,249 --> 00:40:55,946
In the Atlantic, the north-flowing current
is called the Gulf Stream,
329
00:40:56,120 --> 00:41:00,955
and it encloses, in the centre of the ocean,
as all these great whirlpools do,
330
00:41:01,125 --> 00:41:03,992
an area where the waters are almost still.
331
00:41:06,197 --> 00:41:10,759
On their surface float rafts of weed.
It never roots but floats for ever,
332
00:41:10,935 --> 00:41:16,100
rocked sufficiently by the swell to prevent
its topmost fronds from drying out in the sun.
333
00:41:24,281 --> 00:41:25,339
The Portuguese sailors,
334
00:41:25,516 --> 00:41:30,283
looking at the little bladders that keep it afloat
called them sargasso: Grapes.
335
00:41:30,788 --> 00:41:32,517
This is the Sargasso Sea.
336
00:41:32,990 --> 00:41:37,552
Like every other region within the oceans,
it has its own specialised inhabitants.
337
00:41:39,797 --> 00:41:44,598
Small fish shelter in its fronds
and are closely disguised to match them,
338
00:41:44,768 --> 00:41:49,467
and swimming crabs clamber up
and rest on top of the floating mats.
339
00:41:50,374 --> 00:41:55,209
But the Sargasso is one of the least fertile
stretches of water in all the oceans.
340
00:41:55,613 --> 00:41:59,344
Since no currents feed into it,
it receives no nutrients
341
00:41:59,517 --> 00:42:02,418
and its clear waters are largely barren.
342
00:42:07,625 --> 00:42:09,991
But patches of it occasionally break away.
343
00:42:13,697 --> 00:42:15,858
Between the Gulf Stream
and the North American coast
344
00:42:16,033 --> 00:42:20,402
there are cores of cold Sargasso water
surrounded by warm circulating currents
345
00:42:20,571 --> 00:42:25,440
formed when the Gulf Stream meanders
and nips off a segment of the Sargasso,
346
00:42:25,609 --> 00:42:28,100
complete with its weed
and populations of animals.
347
00:42:28,512 --> 00:42:31,572
These warm core-rings,
a hundred or so miles across,
348
00:42:31,749 --> 00:42:35,708
drift down the coast
until they lose their momentum and their warmth,
349
00:42:35,886 --> 00:42:39,083
break up and are swept away again
by the Gulf Stream.
350
00:42:40,958 --> 00:42:45,452
The Gulf Stream continues northwards
along the coast to Newfoundland.
351
00:42:47,598 --> 00:42:52,058
Here, off these bleak fogbound beaches,
it creates an area of seas
352
00:42:52,236 --> 00:42:57,003
that might be seen as one of the most fertile
and productive places on the entire globe,
353
00:42:57,274 --> 00:43:00,732
a place where the full potential richness
of the ocean is realised,
354
00:43:00,911 --> 00:43:05,905
and where animals of all kinds
come to harvest it.
355
00:43:10,154 --> 00:43:15,057
The warm water of the Gulf Stream
is accompanied by steady warm breezes.
356
00:43:15,593 --> 00:43:21,725
And just about here, it meets
a cold current coming down from the Arctic,
357
00:43:21,999 --> 00:43:26,936
and where the warm breezes
meet the icy breath of the Arctic,
358
00:43:27,371 --> 00:43:30,431
they shed their moisture and form these fogs.
359
00:43:30,774 --> 00:43:35,336
And where the two currents meet,
the waters churn and swirl,
360
00:43:35,512 --> 00:43:39,972
and bring up rich nutrients
from the bottom of the sea.
361
00:43:40,284 --> 00:43:42,980
Now, it so happens thatjust off this coast
362
00:43:43,153 --> 00:43:46,680
there is an underwater plateau
where the water is so shallow
363
00:43:46,857 --> 00:43:51,419
that the sun or the light
can get almost always to the bottom,
364
00:43:51,762 --> 00:43:56,563
and so the floating plants of the sea
are always within the range of light,
365
00:43:56,734 --> 00:44:01,967
and they're fed eternally
by these swirling currents bringing up nutrients.
366
00:44:02,706 --> 00:44:07,006
So the plants flourish,
and on them come great shoals of fish
367
00:44:07,177 --> 00:44:10,078
which breed and spawn in such numbers
368
00:44:10,247 --> 00:44:14,206
that at times
the waters seem almost to boil with them.
369
00:44:15,386 --> 00:44:19,516
These are capelin,
a small fish related to the European smelt.
370
00:44:19,890 --> 00:44:22,188
They feed on the plankton in the surface waters,
371
00:44:22,359 --> 00:44:26,295
and in May they gather in vast shoals to spawn.
372
00:44:26,630 --> 00:44:28,291
Some will do so offshore,
373
00:44:28,465 --> 00:44:32,526
but some go to extraordinary trouble
to lay their eggs out of water
374
00:44:32,703 --> 00:44:35,137
where they will be safe from other hungry fish.
375
00:44:38,509 --> 00:44:41,603
The shoals come closer and closer inshore.
376
00:44:49,853 --> 00:44:53,516
Each female capelin can produce 10,000 eggs.
377
00:44:53,891 --> 00:44:58,385
Each wave brings in
tens of thousands of fish again and again.
378
00:44:58,862 --> 00:45:01,592
The number of eggs defies any computation.
379
00:45:01,899 --> 00:45:05,835
They pile up in banks,
as solid as sand along the high-water mark.
380
00:45:08,005 --> 00:45:12,305
Having spawned,
all the males and most of the females die.
381
00:45:26,523 --> 00:45:29,117
The richness that the capelin
gathered from the plankton
382
00:45:29,293 --> 00:45:33,491
and converted into their own flesh
is now gathered by birds.
383
00:45:35,299 --> 00:45:38,996
Shearwaters gorge themselves
on the dying and the dead.
384
00:45:51,081 --> 00:45:54,949
Gannets dive between the scavengers,
taking the live fish.
385
00:46:00,657 --> 00:46:05,788
And still the capelin come in. Even before
they get to the shallows, they are hunted.
386
00:46:08,632 --> 00:46:14,195
Herds of seals come up to the Grand Banks
specially at this time to share in the bonanza.
387
00:47:01,084 --> 00:47:04,520
And here, too, come the biggest hunters of all.
388
00:47:10,093 --> 00:47:11,651
Humpbacked whales.
389
00:47:22,139 --> 00:47:28,009
With each upward lunge, the whale takes in
tons of water and thousands of capelin.
390
00:47:34,885 --> 00:47:38,218
With a mouthful in its jaws,
it brings forward its tongue,
391
00:47:38,388 --> 00:47:42,484
squirts out surplus water through the filter plate
that hang from its upperjaw
392
00:47:42,659 --> 00:47:44,786
and swallows the tiny fish.
393
00:48:08,118 --> 00:48:11,610
The whales have developed a way
of concentrating the capelin shoals
394
00:48:11,788 --> 00:48:15,588
so that they will get the greatest number of fish
in a single mouthful.
395
00:48:16,260 --> 00:48:17,989
It's called bubble-netting.
396
00:48:18,629 --> 00:48:22,224
Those white areas are huge masses of bubbles.
397
00:48:22,933 --> 00:48:25,561
The whales dive deep
below the swarming capelin
398
00:48:25,736 --> 00:48:30,867
and start a slow, spiralling swim upwards,
blowing gusts of bubbles as they rise.
399
00:48:31,141 --> 00:48:34,304
The capelin,
frightened by the circular curtain of bubbles,
400
00:48:34,478 --> 00:48:37,743
rush inwards and form a dense, confused shoal.
401
00:48:37,981 --> 00:48:42,975
The whale rises up in the middle,
jaws agape, and engulfs the lot.
402
00:48:53,397 --> 00:48:56,855
After a few short weeks,
the spawning orgy of the capelin is over.
403
00:48:57,234 --> 00:49:01,170
Their bodies lie in vast drifts
awaiting the processes of decay
404
00:49:01,338 --> 00:49:03,670
which will return their nutrients to the waters,
405
00:49:04,074 --> 00:49:08,977
but even before they disperse,
other bodies appear: Dead squid.
406
00:49:10,347 --> 00:49:13,805
Nobody knows where they have come from,
or why they have died in such numbers,
407
00:49:13,984 --> 00:49:17,044
but these blizzards of bodies
appear most years in July,
408
00:49:17,220 --> 00:49:21,179
and are a sign that shoals
of the living animals are about to arrive.
409
00:49:32,069 --> 00:49:34,902
They will bite any small, moving thing.
410
00:49:35,205 --> 00:49:40,541
To catch them, you don't even need bait.
They simply impale themselves on a naked hook,
411
00:49:40,711 --> 00:49:46,411
so that most summers, fishing villages
on the Newfoundland coast go jigging for squid,
412
00:49:46,583 --> 00:49:48,710
hauling them out by the thousands.
413
00:50:02,866 --> 00:50:06,529
As they're hooked,
they puff out clouds of squid ink.
414
00:50:15,479 --> 00:50:18,607
Hundreds of tons of them
are despatched every year to Japan
415
00:50:18,782 --> 00:50:21,046
where they are a much-prized food.
416
00:50:27,424 --> 00:50:33,454
Mackerel also come to the Grand Banks by
the million to feed on small plankton-feeding fish
417
00:50:35,265 --> 00:50:38,496
They're netted by the ton
by fleets of factory ships,
418
00:50:38,668 --> 00:50:41,796
and their rich flesh is valued
all over the world.
419
00:50:43,840 --> 00:50:47,173
But even the Grand Banks
are not inexhaustible.
420
00:50:48,478 --> 00:50:53,814
During this century, man has fished so skilfully,
so intensively, so unrelentingly,
421
00:50:53,984 --> 00:50:57,442
that he has begun to change
the pattern of life in the sea.
422
00:50:57,754 --> 00:51:01,212
Some kinds of fish have been forced
to change their habits,
423
00:51:01,391 --> 00:51:04,087
others have been driven
close to the edge of extinction.
424
00:51:04,428 --> 00:51:09,593
This little port in Newfoundland,
close to what was once the richest of all seas,
425
00:51:09,766 --> 00:51:12,860
now brings in fewer catches,
426
00:51:13,036 --> 00:51:18,497
and modern fish-processing plants like that one
are mostly standing idle.
427
00:51:18,809 --> 00:51:24,213
So man has changed the sea, just as he's
changed almost every environment in the world.
428
00:51:24,381 --> 00:51:25,939
But he's done something else, too.
429
00:51:26,249 --> 00:51:28,444
He's created new environments,
430
00:51:28,618 --> 00:51:32,247
environments of brick and concrete,
and chromium and plastic.
431
00:51:32,923 --> 00:51:36,017
It's the latest of the world's environments,
432
00:51:36,193 --> 00:51:39,890
and the ways in which plants and animals
have adapted to live in them,
433
00:51:40,063 --> 00:51:43,328
that we're going to look at
in the last of these programmes.
434
00:51:43,378 --> 00:51:47,928
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