Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:36,138 --> 00:00:37,179
These seas
2
00:00:37,180 --> 00:00:40,306
- thousands of miles from nearest land
3
00:00:40,307 --> 00:00:42,402
- are the most sterile on our planet.
4
00:00:42,403 --> 00:00:46,562
These are marine deserts.
5
00:00:47,615 --> 00:00:51,774
But here live the swiftest and the most
powerful of all ocean hunters
6
00:00:59,091 --> 00:01:03,261
Simply finding them
is an immense challenge
7
00:01:04,314 --> 00:01:07,440
but we are about to follow them
as they search for their food
8
00:01:07,441 --> 00:01:11,600
in this little known part of the seas
- the open ocean.
9
00:01:31,437 --> 00:01:35,606
Striped marlin - voracious predators...
that can grow to three metres long.
10
00:01:41,871 --> 00:01:43,965
They hunt mainly in daylight
11
00:01:43,966 --> 00:01:46,050
searching the tropical oceans from close
12
00:01:46,051 --> 00:01:50,210
to the surface down to depths of
a hundred metres or so.
13
00:01:52,305 --> 00:01:55,442
Normally the fish they feed on
are widely dispersed
14
00:01:55,443 --> 00:01:59,602
but sometimes their prey gathers
in dense shoals, like these sardines.
15
00:03:36,649 --> 00:03:40,818
This feast may last for over an hour,
16
00:03:46,041 --> 00:03:50,220
time enough for other hunters
to reach the scene.
17
00:03:50,221 --> 00:03:54,380
Juvenile tuna join in the feeding frenzy.
18
00:04:12,132 --> 00:04:16,291
The noise attracts a giant - a sei whale.
19
00:04:24,651 --> 00:04:28,820
It's fourteen metres long
and twenty tonnes in weight
20
00:04:28,821 --> 00:04:32,990
- and has an appetite to match.
21
00:05:35,607 --> 00:05:39,766
Soon the only sign that the sardines
ever existed are scales
22
00:05:40,819 --> 00:05:44,988
sinking down into the abyss.
23
00:05:46,041 --> 00:05:48,125
Such feasts don't last long.
24
00:05:48,126 --> 00:05:51,252
Within a few short days,
waters that once swarmed...
25
00:05:51,253 --> 00:05:54,390
with food will have been cleaned out.
26
00:05:54,391 --> 00:05:56,474
The hunters must move elsewhere
and once again
27
00:05:56,475 --> 00:06:00,634
start their search of the
seemingly featureless open ocean.
28
00:06:04,825 --> 00:06:07,951
A manta ray - immense - five metres
29
00:06:07,952 --> 00:06:12,111
across from the tip of one wing-like fin
to the tip of the other.
30
00:06:13,164 --> 00:06:16,301
It's travelling economy,
wasting as little energy as possible,
31
00:06:16,302 --> 00:06:20,461
as it glides through
the waters of the tropics.
32
00:06:25,694 --> 00:06:28,820
The remora fish that accompany it travel
33
00:06:28,821 --> 00:06:32,980
more economically still
- by hitching a lift.
34
00:06:34,033 --> 00:06:36,127
Their host is searching for food
- plankton,
35
00:06:36,128 --> 00:06:40,296
the minute fish and invertebrates
that float near the surface.
36
00:06:40,297 --> 00:06:43,424
It needs lots of them
and may cruise for days before...
37
00:06:43,425 --> 00:06:47,594
it finds a good feeding ground.
38
00:06:49,689 --> 00:06:52,816
Dusk, at the edge of a Pacific Island
39
00:06:52,817 --> 00:06:55,943
three thousand miles
from the nearest continent.
40
00:06:55,944 --> 00:07:00,113
Here surgeon fish have assembled to spawn.
41
00:07:01,166 --> 00:07:03,250
As they perform their nuptial dances
42
00:07:03,251 --> 00:07:07,410
they discharge clouds of eggs
and sperm into the water.
43
00:07:08,473 --> 00:07:10,557
The manta must have known this was about
44
00:07:10,558 --> 00:07:14,727
to happen for it arrived at
exactly this critical moment.
45
00:07:14,728 --> 00:07:17,864
And it is not the only one to do so.
46
00:07:17,865 --> 00:07:22,024
Others are here too.
47
00:07:24,120 --> 00:07:27,246
Now all they need to do is
to sweep the water into their mouths
48
00:07:27,247 --> 00:07:31,416
and sieve out the eggs.
49
00:07:56,465 --> 00:08:00,644
Within an hour,
the whole event will be over...
50
00:08:00,645 --> 00:08:02,729
Any surviving eggs will be so dispersed
51
00:08:02,730 --> 00:08:06,889
that they are not worth collecting.
52
00:08:14,207 --> 00:08:16,290
But other perils await them as they join
53
00:08:16,291 --> 00:08:19,417
the clouds of eggs
and larvae and tiny fish
54
00:08:19,418 --> 00:08:23,588
that drift through the
surface waters of the open ocean.
55
00:08:24,641 --> 00:08:28,809
These are the eggs of yellow fin tuna.
56
00:08:28,810 --> 00:08:32,980
If the hatchlings survive, it will
take them two years to become adults.
57
00:08:38,202 --> 00:08:40,286
In three years,
they could be nearly two metres long
58
00:08:40,287 --> 00:08:44,457
and weigh two hundred kilograms.
59
00:08:46,552 --> 00:08:50,711
Perhaps only one in a million
will live as long as that.
60
00:08:51,774 --> 00:08:54,900
They and the other animals
and microscopic plants of the plankton
61
00:08:54,901 --> 00:08:59,061
constitute the basis of all life
out on the open ocean.
62
00:09:05,336 --> 00:09:07,420
A storm petrel dancing on the water.
63
00:09:07,421 --> 00:09:10,547
But this is no amiable waltz.
64
00:09:10,548 --> 00:09:14,717
It's a hunt.
65
00:09:15,770 --> 00:09:17,854
As they hover facing into the wind,
66
00:09:17,855 --> 00:09:22,014
they pick out morsels
from near the surface, including eggs.
67
00:09:31,416 --> 00:09:33,511
Only a tiny percentage
of the developing eggs
68
00:09:33,512 --> 00:09:35,595
will survive long enough to hatch.
69
00:09:35,596 --> 00:09:39,756
These newly emerged tuna
are only three millimetres long
70
00:09:40,808 --> 00:09:44,978
and although they can swim
they're still very vulnerable.
71
00:09:46,031 --> 00:09:48,115
It will be many weeks before they can swim
72
00:09:48,116 --> 00:09:52,275
strongly enough to make any
real headway in the ocean.
73
00:10:02,720 --> 00:10:04,814
After the sun goes down,
74
00:10:04,815 --> 00:10:08,974
other predators rise from the depths
to attack the floating multitudes.
75
00:10:28,811 --> 00:10:32,970
Darkness shrouds the arrival of
battalions of dangerous drifting predators
76
00:10:48,637 --> 00:10:51,763
These shimmering comb
jellies - sea gooseberries
77
00:10:51,764 --> 00:10:55,933
- trap their prey
with sticky net-like webs
78
00:10:55,934 --> 00:11:00,103
One ill-timed fin-stroke could bring
certain death to a hatchling fish.
79
00:11:03,241 --> 00:11:05,325
There are many kinds of these comb jellies
80
00:11:05,326 --> 00:11:09,495
- all of them very effective hunters.
81
00:11:20,982 --> 00:11:23,066
By dawn, most of the nocturnal feeders
82
00:11:23,067 --> 00:11:27,226
will have returned to the depths.
83
00:11:30,374 --> 00:11:32,458
The surviving hatchlings,
84
00:11:32,459 --> 00:11:36,618
however,
have already started on their travels.
85
00:11:47,063 --> 00:11:48,104
Vast current systems,
86
00:11:48,105 --> 00:11:52,275
like immense rivers,
carry them around the ocean basins.
87
00:11:54,370 --> 00:11:57,496
The boundaries between
these masses of moving water...
88
00:11:57,497 --> 00:12:00,634
form invisible barriers that can trap
89
00:12:00,635 --> 00:12:04,794
both plankton and nutrients carried up
from the depths.
90
00:12:10,027 --> 00:12:12,111
So parts of the ocean become rich
91
00:12:12,112 --> 00:12:16,271
with food for days or even weeks at a time
92
00:12:17,324 --> 00:12:21,493
This attracts vast schools of
plankton-feeding fish - like these sardine
93
00:12:29,843 --> 00:12:31,937
They take in water through their mouths
94
00:12:31,938 --> 00:12:34,022
and expel it through their gills
95
00:12:34,023 --> 00:12:38,182
sieving out the plankton which
is then funnelled down their throats.
96
00:12:44,457 --> 00:12:48,626
The immense schools travel along
the boundaries of the currents
97
00:12:48,627 --> 00:12:52,796
- seeking the spots where
the plankton is thickest.
98
00:12:55,934 --> 00:12:59,060
As the position of the current
boundaries changes constantly,
99
00:12:59,061 --> 00:13:03,230
so does both the supply of plankton
and the numbers of fish.
100
00:13:18,887 --> 00:13:22,013
A small pod of Pacific Spotted Dolphin
101
00:13:22,014 --> 00:13:25,151
- twenty miles from the coast of Panama.
102
00:13:25,152 --> 00:13:27,236
Like all predators,
they seek parts of the ocean
103
00:13:27,237 --> 00:13:31,396
where their food is thickest.
104
00:13:39,756 --> 00:13:42,882
They cover
as much as hundred miles in a day.
105
00:13:42,883 --> 00:13:47,053
And while they travel, they play.
106
00:14:02,709 --> 00:14:06,888
They have detected the sound of
schooling fish from hundreds of metres away
107
00:14:06,889 --> 00:14:11,058
and start to track down
the shoals using sonar
108
00:14:11,059 --> 00:14:15,218
- leaving their toys behind them.
109
00:14:17,324 --> 00:14:21,483
For the hunted
there are few places to hide.
110
00:14:27,758 --> 00:14:28,799
Schooling mackerel.
111
00:14:28,800 --> 00:14:32,960
They have already sensed the sonar beams
of approaching dolphin.
112
00:14:38,192 --> 00:14:41,319
Their only defence
is to gather into a ball.
113
00:14:41,320 --> 00:14:45,488
Any individual that stayed out
of the shoal would be quickly picked off.
114
00:14:45,489 --> 00:14:49,659
Within it,
there is at least some chance of survival.
115
00:14:59,061 --> 00:15:02,187
The noise of the attack
alerts another predator
116
00:15:02,188 --> 00:15:06,347
- a sailfish, one of the
fastest fish in the ocean.
117
00:15:10,538 --> 00:15:12,622
It has detected rapid vibrations
in the water
118
00:15:12,623 --> 00:15:16,782
and is searching for the cause.
119
00:15:29,322 --> 00:15:31,405
Sailfish rely on eyesight
120
00:15:31,406 --> 00:15:32,448
for their final approach
121
00:15:32,449 --> 00:15:36,608
so they hunt mainly in daylight.
122
00:15:40,798 --> 00:15:43,925
When sailfish become excited
they change colour
123
00:15:43,926 --> 00:15:47,052
lighting up with bright blue stripes.
124
00:15:47,053 --> 00:15:49,147
Since mackerel eyes
are especially sensitive
125
00:15:49,148 --> 00:15:52,274
to blue and ultraviolet,
these colours confuse them
126
00:15:52,275 --> 00:15:56,434
- making them easier to catch.
127
00:16:37,140 --> 00:16:41,319
Far below, a blue shark returns
from a squid-hunting trip in the
128
00:16:41,320 --> 00:16:44,446
cold darkness three hundred metres down.
129
00:16:44,447 --> 00:16:48,606
It's heading for the surface to
reheat in the warmer water.
130
00:16:50,701 --> 00:16:53,838
As it ascends,
it detects the smell of oils
131
00:16:53,839 --> 00:16:57,998
and proteins shed into the water
by the panicked mackerel.
132
00:17:02,188 --> 00:17:03,230
The trail leads both the shark
133
00:17:03,231 --> 00:17:07,390
and its attendant pilot fish
towards an easy meal.
134
00:17:12,623 --> 00:17:14,707
Scraps and casualties float
135
00:17:14,708 --> 00:17:18,867
in the wake of the passing mackerel school
136
00:17:23,057 --> 00:17:25,141
Throughout the ocean,
predators and prey are locked
137
00:17:25,142 --> 00:17:29,301
in a deadly three-dimensional
contest of hide and seek
138
00:17:30,354 --> 00:17:32,438
played out over immense distances.
139
00:17:32,439 --> 00:17:36,608
To survive they must travel.
140
00:17:41,831 --> 00:17:43,925
The huge four metre long blue-fin tuna
141
00:17:43,926 --> 00:17:47,052
has special blood vessels that enable it
142
00:17:47,053 --> 00:17:51,212
to keep its body temperature significantly
warmer than the surrounding water.
143
00:17:56,445 --> 00:17:59,571
As a result,
they can survive in much colder conditions
144
00:17:59,572 --> 00:18:02,698
than any other tuna
and they travel thousands of
145
00:18:02,699 --> 00:18:04,793
miles away from their spawning grounds
146
00:18:04,794 --> 00:18:08,963
in the tropics to hunt in cold seas
147
00:18:08,964 --> 00:18:12,090
where the food supply is richest.
148
00:18:12,091 --> 00:18:14,175
Ocean travellers come in many guises
149
00:18:14,176 --> 00:18:18,346
- and few are stranger than this...
150
00:18:23,568 --> 00:18:27,737
crab that spends much of its life afloat.
151
00:18:34,002 --> 00:18:38,172
It is a worrying passer-by
for booby birds with delicate toes.
152
00:18:58,009 --> 00:19:00,092
Many floaters are little more than jelly,
153
00:19:00,093 --> 00:19:04,252
enclosed in membranes,
but they may drift for vast distances.
154
00:19:06,348 --> 00:19:10,517
And turtles, like these olive ridleys,
migrate thousands of miles every year.
155
00:19:16,782 --> 00:19:18,876
The ocean is full of such wanderers,
156
00:19:18,877 --> 00:19:20,961
riding the currents, and doing their best
157
00:19:20,962 --> 00:19:24,088
to avoid enemies while
they search for food
158
00:19:24,089 --> 00:19:28,268
and a safe place to breed...
159
00:19:28,269 --> 00:19:31,395
Which is exactly what these rays are doing
160
00:19:31,396 --> 00:19:34,523
- forming the two-mile-high-club,
161
00:19:34,524 --> 00:19:36,607
gathering together
for courtship on the wing,
162
00:19:36,608 --> 00:19:40,778
far above the ocean floor.
163
00:20:05,827 --> 00:20:07,910
More nomads - flying fish.
164
00:20:07,911 --> 00:20:11,048
They seem to be
on every large predator's menu,
165
00:20:11,049 --> 00:20:15,208
so their whole life is spent
on the run in the open ocean.
166
00:20:18,346 --> 00:20:20,440
They don't scatter their eggs
167
00:20:20,441 --> 00:20:24,600
but lay them on pieces of flotsam
like this palm frond.
168
00:20:26,695 --> 00:20:28,779
If the quality of water is right,
169
00:20:28,780 --> 00:20:30,874
they will attach their eggs to the frond,
170
00:20:30,875 --> 00:20:35,034
which will then serve as a kind
of life-raft for their offspring.
171
00:20:38,172 --> 00:20:42,342
But it's not only flying fish
that seek nurseries.
172
00:20:46,522 --> 00:20:50,681
Any piece of floating debris can serve
as a shelter under which baby fish can hide
173
00:20:56,956 --> 00:20:59,040
The only draw back, is that predators
174
00:20:59,041 --> 00:21:01,124
like this wahoo always check up on
175
00:21:01,125 --> 00:21:05,304
who's hanging about in the shadows.
176
00:21:05,305 --> 00:21:09,465
The wahoo may trail the flotsam for weeks.
177
00:21:13,655 --> 00:21:15,739
Few bits of flotsam are without their
178
00:21:15,740 --> 00:21:19,908
quota of lodgers - even man-made
junk attracts them.
179
00:21:19,909 --> 00:21:21,993
And some, like this oceanic trigger fish,
180
00:21:21,994 --> 00:21:26,164
defend their squatters rights with vigour
181
00:21:34,524 --> 00:21:38,683
The triggers, in fact,
tend to claim all the prime residences.
182
00:21:43,916 --> 00:21:47,042
Out here,
even discarded netting can provide
183
00:21:47,043 --> 00:21:48,084
valuable shelter, so
184
00:21:48,085 --> 00:21:49,127
- in a bizarre twist
185
00:21:49,128 --> 00:21:53,287
- a wrecked trawl net like this can end up
as a sanctuary for fish
186
00:21:54,350 --> 00:21:58,509
- until such time as it finally sinks.
187
00:22:02,689 --> 00:22:05,826
Indeed, a single large piece of flotsam
188
00:22:05,827 --> 00:22:08,953
can be the reason why several
square miles of open ocean,
189
00:22:08,954 --> 00:22:13,113
instead of being empty, will support
a fish population of hundreds of tonnes.
190
00:22:18,346 --> 00:22:21,472
This huge clump of seaweed
is doing exactly that.
191
00:22:21,473 --> 00:22:25,632
It is a giant kelp plant, ripped from
the rocks off the coast of California.
192
00:22:31,907 --> 00:22:35,034
Now, it's floating above thousands
of metres of water,
193
00:22:35,035 --> 00:22:39,204
held up by its gas filled floats.
194
00:22:42,342 --> 00:22:46,501
Clouds of young rockfish are growing up
in the safety of its shadow.
195
00:22:52,776 --> 00:22:56,935
Giants also seek out this algal flotsam.
196
00:22:59,041 --> 00:23:00,082
This is a sunfish.
197
00:23:00,083 --> 00:23:04,242
It can measure as much as four metres
from fin-tip to fin-tip.
198
00:23:05,295 --> 00:23:09,465
Rather surprisingly, it has the record
as the heaviest bony fish in the sea.
199
00:23:12,602 --> 00:23:16,771
Sunfish spend much of their time at
depth where they feed on jellyfish;
200
00:23:16,772 --> 00:23:20,951
but it is cold and dark down there
so from time to time,
201
00:23:20,952 --> 00:23:25,111
they seek a little rest and recuperation
and warm up near the surface.
202
00:23:26,164 --> 00:23:30,333
They too are looking for floating
kelp plants.
203
00:23:31,386 --> 00:23:33,470
Not for shelter but because here they
204
00:23:33,471 --> 00:23:37,630
can find a particular kind of fish
that only lives in such places.
205
00:23:42,863 --> 00:23:47,032
Half moon fish.
206
00:23:47,033 --> 00:23:50,169
The sunfish form up in an orderly queue.
207
00:23:50,170 --> 00:23:52,254
They have a problem.
208
00:23:52,255 --> 00:23:56,414
Their skin is covered in parasites.
209
00:24:05,816 --> 00:24:07,900
The hungry half-moons will help.
210
00:24:07,901 --> 00:24:09,995
The sunfish turn their heads towards
211
00:24:09,996 --> 00:24:14,156
the surface as a clear invitation
to their personal hygienists.
212
00:24:15,208 --> 00:24:17,292
The half-moons nip off - and eat
213
00:24:17,293 --> 00:24:21,463
- every parasite they can find.
214
00:24:38,162 --> 00:24:40,246
If the half moons don't do the job
215
00:24:40,247 --> 00:24:44,416
- there is another rather drastic
treatment available here.
216
00:24:45,469 --> 00:24:49,628
Gulls rest on the floating kelp.
217
00:24:50,681 --> 00:24:52,775
And if the sunfish
send the right signals...
218
00:24:52,776 --> 00:24:56,935
the gulls will investigate.
219
00:25:03,210 --> 00:25:07,370
Their beaks can dig out
the most stubborn parasites.
220
00:25:28,249 --> 00:25:32,408
But even the very best of health clinics
can only trade on a temporary basis.
221
00:25:34,514 --> 00:25:35,555
The seaweed rafts are rotting
222
00:25:35,556 --> 00:25:39,715
and will eventually lose their buoyancy.
223
00:25:48,075 --> 00:25:51,201
Then their lodgers
will have to find a new home.
224
00:25:51,202 --> 00:25:53,286
If they can't, they will be eaten,
225
00:25:53,287 --> 00:25:57,457
or die and sink down into the abyss.
226
00:26:08,944 --> 00:26:13,103
But the open ocean is not entirely
devoid of permanent shelter.
227
00:26:19,378 --> 00:26:23,537
A volcano is erupting from the seafloor
and it is still growing.
228
00:26:59,031 --> 00:27:03,190
It has formed an island some seventy miles
from the coast of New Zealand.
229
00:27:08,423 --> 00:27:10,506
Some juvenile reef fish
have already arrived,
230
00:27:10,507 --> 00:27:13,634
carried here by a lucky current.
231
00:27:13,635 --> 00:27:15,718
Now they are growing up in the shelter of
232
00:27:15,719 --> 00:27:19,889
the weeds growing around
the island's fringes.
233
00:27:26,154 --> 00:27:28,248
More plankton and juvenile fish
234
00:27:28,249 --> 00:27:32,417
are being swept by currents straight
towards the island.
235
00:27:32,418 --> 00:27:36,578
But now there is a welcoming committee.
236
00:27:38,683 --> 00:27:40,767
Schools of trevally and blue maomao
237
00:27:40,768 --> 00:27:44,927
are patrolling the surface water.
238
00:27:51,202 --> 00:27:55,362
All are in search of a meal.
239
00:27:59,552 --> 00:28:03,711
These one kilo fish snap up
every morsel of plankton they find.
240
00:28:14,156 --> 00:28:17,282
At times, the currents sweeping in from
241
00:28:17,283 --> 00:28:21,453
the open ocean bring with them all kinds
of small creatures in dense concentrations
242
00:28:23,548 --> 00:28:27,707
These are mysid shrimps.
243
00:29:00,063 --> 00:29:04,242
Very little that is edible
is left after such feasts.
244
00:29:04,243 --> 00:29:08,402
Islands are far from being safe
havens for plankton.
245
00:29:13,635 --> 00:29:15,718
The Pacific Ocean, however,
246
00:29:15,719 --> 00:29:17,803
is peppered with
over twenty three thousand...
247
00:29:17,804 --> 00:29:21,973
slands as well as
countless other submerged mountains
248
00:29:21,974 --> 00:29:26,143
- sea mounts - whose summits
do not break the surface.
249
00:29:28,239 --> 00:29:30,322
Juvenile fish, for their first few months
250
00:29:30,323 --> 00:29:34,493
would do well to avoid such places.
251
00:29:36,588 --> 00:29:38,672
These yellow-fin tuna, however,
252
00:29:38,673 --> 00:29:41,799
are now more than six months old
and forty centimetres long
253
00:29:41,800 --> 00:29:44,937
- big enough to be able to eat fry,
254
00:29:44,938 --> 00:29:48,064
- so sea mounts for them are promising
255
00:29:48,065 --> 00:29:52,224
feeding grounds where they may
hunt for several months.
256
00:29:58,499 --> 00:30:00,583
The base of a seamount.
257
00:30:00,584 --> 00:30:04,743
As currents sweep towards it they are
deflected up its towering walls.
258
00:30:13,103 --> 00:30:14,145
The water, coming from the depths,
259
00:30:14,146 --> 00:30:18,315
carries both nutrients and
plankton to the surface.
260
00:30:24,580 --> 00:30:27,716
Numerous reef fish take up
permanent residence here,
261
00:30:27,717 --> 00:30:29,801
feeding where the currents are strongest
262
00:30:29,802 --> 00:30:33,961
and the plankton most dense.
263
00:30:42,321 --> 00:30:46,500
Where the cold water mixes with
warmer water at the surface,
264
00:30:46,501 --> 00:30:48,585
there is a strange shimmering effect
265
00:30:48,586 --> 00:30:52,745
- a clear sign that the currents
are running strongly.
266
00:31:10,497 --> 00:31:14,656
But these currents attract
more than just coastal fish.
267
00:31:17,804 --> 00:31:21,964
Giants come here from the open ocean....
268
00:31:23,016 --> 00:31:27,176
Hammerhead sharks - and in great numbers.
269
00:31:32,408 --> 00:31:36,567
During the day, they circle the sea mount
looking for small fish at the reef edges.
270
00:31:39,715 --> 00:31:41,799
But not in order to eat them.
271
00:31:41,800 --> 00:31:43,884
They, like the sunfish,
272
00:31:43,885 --> 00:31:48,044
are looking for cleaners to rid
them of their parasites.
273
00:31:54,319 --> 00:31:56,403
White-tip reef sharks gather here too.
274
00:31:56,404 --> 00:32:00,574
They do eat reef fish.
275
00:32:08,923 --> 00:32:11,018
But they prefer to hunt at night,
276
00:32:11,019 --> 00:32:15,187
when the reef fish are sleepy
and easier to catch.
277
00:32:15,188 --> 00:32:19,347
Far better to rest by day and
allow the cleaners to do their work...
278
00:32:27,707 --> 00:32:31,877
Even swarms of breeding trigger
aren't a serious temptation.
279
00:32:41,279 --> 00:32:44,405
These triggers spend much of
their time in open water,
280
00:32:44,406 --> 00:32:48,565
but they have come
to the seamount to spawn.
281
00:32:56,925 --> 00:32:59,009
Trigger eggs are good food
282
00:32:59,010 --> 00:33:03,180
and the plankton-feeders gather what they
can before the current sweeps them away.
283
00:33:05,275 --> 00:33:07,359
This whole community is only here
284
00:33:07,360 --> 00:33:09,444
because of the nutrients and plankton
285
00:33:09,445 --> 00:33:13,614
that the seamount deflected into
the surface waters.
286
00:33:15,709 --> 00:33:19,868
But ocean-going hunters
are never far away.
287
00:33:21,964 --> 00:33:24,058
Silky shark specialise in picking off
288
00:33:24,059 --> 00:33:26,143
injured fish and constantly check over
289
00:33:26,144 --> 00:33:30,303
the residents around the seamount.
290
00:33:34,493 --> 00:33:35,535
At some times of the year,
291
00:33:35,536 --> 00:33:38,662
seasonal changes make the currents
especially rich in nutrients
292
00:33:38,663 --> 00:33:40,747
and then the ocean around the seamount
293
00:33:40,748 --> 00:33:44,917
becomes a virtual soup of plankton.
294
00:33:52,224 --> 00:33:56,394
At such times, hunters gather
in astonishing numbers.
295
00:34:06,839 --> 00:34:08,922
Bonito, smaller relatives of the tuna.
296
00:34:08,923 --> 00:34:12,050
They are searching
for still smaller plankton
297
00:34:12,051 --> 00:34:16,220
feeders that have been
attracted by the bloom.
298
00:34:17,273 --> 00:34:21,432
So are these jacks
- and their prey is nearby.
299
00:34:27,707 --> 00:34:30,834
A school of anchovetta has strayed up
near the surface,
300
00:34:30,835 --> 00:34:32,918
even though it is broad daylight
301
00:34:32,919 --> 00:34:37,089
and hunters are on the prowl.
302
00:34:40,226 --> 00:34:42,310
These small fish can already feel
303
00:34:42,311 --> 00:34:44,395
the vibrations
of the approaching predators.
304
00:34:44,396 --> 00:34:47,533
Swimming at speed,
they have formed into a ball
305
00:34:47,534 --> 00:34:51,693
and now they must wait for whatever comes.
306
00:35:01,095 --> 00:35:05,254
They're been detected.
307
00:35:17,794 --> 00:35:21,953
At first the sheer scale of the bait ball
seems to daunt the predators.
308
00:35:36,568 --> 00:35:40,737
But now the bonito arrive
and launch the first attack.
309
00:35:48,044 --> 00:35:52,214
Still the bait ball holds together.
310
00:35:59,532 --> 00:36:01,615
The young yellow fin tuna move in.
311
00:36:01,616 --> 00:36:04,743
The speed of this attack is so great
312
00:36:04,744 --> 00:36:08,903
that gradually groups of anchovetta are
splintered from the main fish ball.
313
00:37:13,614 --> 00:37:15,698
Before long the currents will shift
314
00:37:15,699 --> 00:37:19,858
and the ocean will become once more
a blue tropical desert, plankton free.
315
00:37:21,954 --> 00:37:26,123
And the hunters will have to move on.
316
00:37:34,483 --> 00:37:38,642
Spinner dolphins,
still searching for food.
317
00:37:44,917 --> 00:37:49,086
Their twisting leaps are, apparently,
purely social displays.
318
00:37:49,087 --> 00:37:51,171
Since the hunting has been good
319
00:37:51,172 --> 00:37:55,341
many hundred have gathered together
in this exuberant super-pod.
320
00:39:03,170 --> 00:39:07,329
But now the spinners are
starting to hunt once more.
321
00:39:12,562 --> 00:39:16,730
Their skill in tracking food
is not a secret.
322
00:39:16,731 --> 00:39:20,910
Yellow-fin tuna must be aware of it
for they regularly follow them.
323
00:39:20,911 --> 00:39:22,995
But only adult tuna in their second
324
00:39:22,996 --> 00:39:26,122
or third year of life
have sufficient stamina
325
00:39:26,123 --> 00:39:30,293
to keep up with the fast-moving spinners.
326
00:39:45,950 --> 00:39:50,129
These are another kind - Common Dolphin.
327
00:39:50,130 --> 00:39:54,298
They too are on the move.
328
00:39:54,299 --> 00:39:56,383
As they travel - ever inquisitive
329
00:39:56,384 --> 00:39:59,520
they pay a call on one of their
larger relations
330
00:39:59,521 --> 00:40:03,690
- a pilot whale.
331
00:40:03,691 --> 00:40:04,732
The whale is not hunting.
332
00:40:04,733 --> 00:40:08,902
It's on its way to its breeding grounds
in the Mediterranean.
333
00:40:08,903 --> 00:40:13,082
Pilot whales normally hunt in
small family groups but in mid-summer
334
00:40:13,083 --> 00:40:16,209
they head for
traditional socialising grounds
335
00:40:16,210 --> 00:40:20,369
where they will assemble in
super herds several hundred strong.
336
00:40:23,517 --> 00:40:25,601
Already two families have joined together.
337
00:40:25,602 --> 00:40:29,761
The males are starting to compete
for the favours of the females.
338
00:41:02,128 --> 00:41:06,287
As the weeks pass by these group rubbing-
sessions will become more overtly sexual.
339
00:41:07,340 --> 00:41:11,499
But now - it's just flirting in the sun.
340
00:41:33,431 --> 00:41:37,599
Timing in the ocean can be crucial.
341
00:41:37,600 --> 00:41:40,726
In summer, the northern Atlantic waters
are beginning to warm.
342
00:41:40,727 --> 00:41:43,864
The hunting is good here
and by June predators
343
00:41:43,865 --> 00:41:48,024
from southern waters are
heading towards the Azores.
344
00:41:57,426 --> 00:42:01,586
These are more Common Dolphin.
345
00:42:07,861 --> 00:42:09,945
Like most oceanic dolphins
346
00:42:09,946 --> 00:42:14,105
they too often travel in huge herds
containing many different families.
347
00:42:20,380 --> 00:42:24,539
There is seldom enough prey in
any one place to feed such numbers.
348
00:42:29,772 --> 00:42:33,931
So small groups leave the super-pod
and set off on hunting expeditions.
349
00:42:39,164 --> 00:42:43,323
This group will be away from
the main herd for several hours.
350
00:42:52,725 --> 00:42:56,904
By mid-day they're nearing
the Islands of the Azores
351
00:42:56,905 --> 00:43:01,064
- nine hundred miles west
of the Portuguese coast.
352
00:43:04,202 --> 00:43:08,372
Other hunters are already here
- Cory's Shearwaters.
353
00:43:14,636 --> 00:43:17,773
Half a million of these birds breed on
the Azores every year
354
00:43:17,774 --> 00:43:20,900
and scour the nearby ocean for food.
355
00:43:20,901 --> 00:43:22,985
Right now there is insufficient wind
356
00:43:22,986 --> 00:43:26,112
to support gliding flight
and since flapping
357
00:43:26,113 --> 00:43:28,207
is a waste of energy they sit out the calm
358
00:43:28,208 --> 00:43:32,367
clustered in rafts
and riding the gentle swells.
359
00:43:50,119 --> 00:43:54,279
By mid-afternoon the dolphin are
starting to hunt in earnest.
360
00:44:01,596 --> 00:44:03,680
As the sea breeze picks up,
361
00:44:03,681 --> 00:44:07,840
the shearwaters take to the air once more.
362
00:44:17,242 --> 00:44:21,412
Out to sea, the dolphin have found prey....
363
00:44:25,592 --> 00:44:29,751
They are driving a shoal of
small mackerel up towards the surface.
364
00:44:38,111 --> 00:44:40,195
The shearwaters crowd the skies above,
365
00:44:40,196 --> 00:44:44,365
following the dolphins' every turn.
366
00:44:52,725 --> 00:44:56,885
The mackerel are still some metres down.
367
00:44:57,937 --> 00:45:00,021
But when the baitfish
come sufficiently close,
368
00:45:00,022 --> 00:45:04,201
the airborne division makes its move.
369
00:45:04,202 --> 00:45:06,286
Far from being mere bystanders,
370
00:45:06,287 --> 00:45:10,446
the shearwaters can now become
underwater predators themselves.
371
00:45:14,637 --> 00:45:18,796
Incredibly they can dive down to
depths of several metres.
372
00:45:21,933 --> 00:45:22,985
The hunting dolphin prevent the mackerel
373
00:45:22,986 --> 00:45:27,145
from escaping downwards and
both predators gorge themselves.
374
00:45:54,289 --> 00:45:58,448
Soon the diving birds outnumber the dolphin
and even drive them away from their meal.
375
00:46:01,586 --> 00:46:05,755
But another squadron of predators
arrives to replace the dolphin.
376
00:46:07,851 --> 00:46:12,019
Adult yellow-fin tuna.
377
00:46:12,020 --> 00:46:16,190
These are giants - two metres long.
378
00:46:21,412 --> 00:46:25,571
They are heading directly
for the bait ball.
379
00:47:25,061 --> 00:47:27,144
Despite the arrival of the giant fish,
380
00:47:27,145 --> 00:47:31,315
the shearwater continue to
press home their attack unfazed.
381
00:47:50,109 --> 00:47:54,268
Eventually the tuna move on, leaving the
shearwaters to battle among themselves.
382
00:48:03,671 --> 00:48:06,797
As long as a predatory fish or a dolphin
383
00:48:06,798 --> 00:48:09,935
remains at the scene the
mackerel can't escape to safety.
384
00:48:09,936 --> 00:48:13,062
But when the little skipjack tuna
start to move away,
385
00:48:13,063 --> 00:48:17,222
gradually the bait ball begins to sink
in to the depths towards safety.
386
00:48:29,751 --> 00:48:33,921
The shearwaters follow it down to the
very limit of their breath-holding ability
387
00:48:34,974 --> 00:48:39,133
perhaps as deep as fifteen metres.
388
00:48:44,366 --> 00:48:48,525
At last, even they are forced
to leave their quarry.
389
00:49:00,012 --> 00:49:03,149
However good or bad
this summer's feeding may be
390
00:49:03,150 --> 00:49:05,233
within three months winter will be
391
00:49:05,234 --> 00:49:09,394
on its way and the temperature of these
waters will drop by a few degrees.
392
00:49:10,446 --> 00:49:14,625
Then the ocean hunters will
abandon the Azores once more.
393
00:49:14,626 --> 00:49:18,786
As ever, they will move on - searching for
another feeding opportunity,
394
00:49:19,838 --> 00:49:24,008
the next pulse of life in the distant
reaches of the Open Ocean.
32201
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.