1. Dwarfed by the vast expanse
of the open oceanCopy !req
2. the biggest animal
that has ever lived on our planet.Copy !req
3. A blue whale, 30 metres long
and weighing over 200 tonnesCopy !req
4. It's far bigger
than even the biggest dinosaurCopy !req
5. Its tongue weighs as much as an elephantCopy !req
6. Its heart is the size of a carCopy !req
7. And some of its blood vessels are so wide
that you could swim down themCopy !req
8. Its tail alone is the width
of a small aircraft wingsCopy !req
9. Its streamlining, close to perfection,
enables it to cruise at twenty knotsCopy !req
10. It's one of the fastest animals in the seaCopy !req
11. The ocean's largest inhabitant feeds
Almost exclusively on one of the smallestCopy !req
12. krill, a crustacean
just a few centimetres longCopy !req
13. Gathered in a shoal,
krill stain the sea red and a single blueCopy !req
14. whale in a day
can consume forty million of themCopy !req
15. Despite the enormous size of blue whales,
we know very little about themCopy !req
16. Their migration
routes are still a mystery andCopy !req
17. we have absolutely no idea
where they go to breedCopy !req
18. They are a dramatic reminder of how muchCopy !req
19. we still have to learn about the ocean and
the creatures that live thereCopy !req
20. Our planet is a blue planetCopy !req
21. Over seventy percent of
it is covered by the seaCopy !req
22. The Pacific Ocean
alone covers half the globeCopy !req
23. You can fly across it non-stop
for twelve hoursCopy !req
24. and still see nothing
more than a speck of landCopy !req
25. This series will reveal the complete
natural history of our ocean planet fromCopy !req
26. its familiar shores to the mysteries
of its deepest seasCopy !req
27. By volume, the ocean makes up 97% of
the earth inhabitable spaceCopy !req
28. And the sheer quantity of marine lifeCopy !req
29. it contains far exceeds that
which inhabits the landCopy !req
30. But life in the ocean
is not evenly spread.Copy !req
31. It's regulated by the path
of currents carrying nutrientsCopy !req
32. and the varying power of the sunCopy !req
33. In this first programme
we will see how these two forces interactCopy !req
34. to control the distribution of life
from the coral seas ... to the polar wastesCopy !req
35. The sheer physical power
of the ocean dominates our planetCopy !req
36. It profoundly influences
the weather of all the worldCopy !req
37. Water vapour rising
from it forms the cloudsCopy !req
38. and generates the storms that ultimately
will drench the landCopy !req
39. The great waves
that roar in towards the shoresCopy !req
40. are dramatic demonstrations of its powerCopy !req
41. Waves originate far out at seaCopy !req
42. There,
even gentle breezes can cause ripplesCopy !req
43. and ripples grow into swellsCopy !req
44. Out in the open ocean, unimpeded by land,
such swells can become giganticCopy !req
45. It's only when an ocean swell
eventually reaches shallow waterCopy !req
46. that it starts to breakCopy !req
47. As it approaches the coastCopy !req
48. the water at the bottom of the swell
is slowed by contact with the sea bedCopy !req
49. The top of the swell,
still travelling fast,Copy !req
50. starts to roll over
and so the wave breaksCopy !req
51. The ocean never rests.Copy !req
52. Huge currents, such as the Gulf Stream,Copy !req
53. keep its waters constantly
on the move all round the globeCopy !req
54. It's these currents
more than any other factorCopy !req
55. that control the distribution of
nutrients and life in the seasCopy !req
56. A tiny island lost in the midst
of the PacificCopy !req
57. It's the tip of a huge mountainCopy !req
58. that rises precipitously from
the sea floor thousands of metres belowCopy !req
59. The nearest land
is three hundred miles awayCopy !req
60. Isolated sea mounts
like this one create oasesCopy !req
61. where life can flourish...Copy !req
62. in the comparatively empty expanses
of the open oceanCopy !req
63. But all the creatures
that swim beside it wouldCopy !req
64. not be here were it not for
one key factor - the deep ocean currentsCopy !req
65. Far below the surface they collide with
the island's flanksCopy !req
66. and are deflected upwardsCopy !req
67. bringing with them from the depths
a rich soup of nutrientsCopy !req
68. Such up-wellings
attract great concentrations of lifeCopy !req
69. Most of the fish here
are permanent residents,Copy !req
70. feeding on the plankton, the tiny floating
plants and animals that are nourishedCopy !req
71. by the richness brought up from the depthsCopy !req
72. And they in turn,
attract visitors from the open oceanCopy !req
73. Tuna.Copy !req
74. The plankton feeders are easy targetsCopy !req
75. All this action attracts
even larger predators...Copy !req
76. Sharks!Copy !req
77. Hundreds of sharks.Copy !req
78. These silky sharks are
normally ocean-going speciesCopy !req
79. but the sea mounts in the eastern Pacific,Copy !req
80. like Cocos, Malpelo and the Galapagos,Copy !req
81. attract silkies in huge groups
up to five hundred strongCopy !req
82. Silkies seem to specialize
in taking injured fishCopy !req
83. and constantly circle sea mounts on
the look out for the chance to do soCopy !req
84. But Silkies are not the only visitorsCopy !req
85. Hammerheads gather
in some of the largest sharkCopy !req
86. shoals to be found anywhere in the oceanCopy !req
87. Sometimes thousands will circle
over a single sea mountCopy !req
88. But these sharks are not here for foodCopy !req
89. They have come for another reasonCopy !req
90. Some of the locals
provide a cleaning serviceCopy !req
91. Following the last El Nino year,Copy !req
92. when a rise in water temperaturesCopy !req
93. caused many sharks to suffer
from fungal infections,Copy !req
94. the number of hammerheads visiting the sea
mounts reached record levelsCopy !req
95. Nutrients also well up to the surface
along the coasts of the continentsCopy !req
96. This is Natal
on South Africa's eastern seaboardCopy !req
97. It's June and just off-shore,
strange black patches have appearedCopy !req
98. They look like immense oil
slicks up to a mile longCopy !req
99. But this is a living slickCopy !req
100. Millions and millions
of sardines on a marineCopy !req
101. migration that in terms of sheer biomassCopy !req
102. rivals that of the wildebeest
on the grasslands of AfricaCopy !req
103. These fish live for most of the timeCopy !req
104. in the cold waters south of the Cape,Copy !req
105. but each year the coastal currents reverseCopy !req
106. The warm Agulhas current thatCopy !req
107. usually flows down from the northCopy !req
108. has been displaced by cold water
coming up from the southCopy !req
109. and that has brought up rich nutrientsCopy !req
110. They, in turn,
have created a bloom of planktonCopy !req
111. - and the sardines are now feasting on itCopy !req
112. As the sardines travel north,Copy !req
113. a whole caravan of predators follow themCopy !req
114. Thousands of Cape Gannets
track the sardinesCopy !req
115. They nested off the CapeCopy !req
116. and timed their breeding so that
their newly-fledged chicksCopy !req
117. can join them in pursuing the shoalsCopy !req
118. Below water, hundreds of sharks
have also joined the caravanCopy !req
119. These are Bronze whaler sharks,Copy !req
120. a cold water species that normally
lives much further southCopy !req
121. These three-metre sharks
cut such great swathesCopy !req
122. through the sardine shoals that their
tracks are clearly visible from the airCopy !req
123. Harried by packs of predators and
swept in by the action of the waves,Copy !req
124. the sardine shoals are penned
close to the shoreCopy !req
125. Common dolphin are coming in
from the open ocean to join the feastCopy !req
126. There are over a thousand of them
in this one schoolCopy !req
127. When they catch up with the sardines,
the action really beginsCopy !req
128. Working together,
they drive the shoal towards the surfaceCopy !req
129. It is easier for the dolphins
to snatch fish up hereCopy !req
130. Now the sardines have no escapeCopy !req
131. Thanks to the dolphins, the sardines have
come within the diving range of the gannetsCopy !req
132. Hundreds of white arrows shoot
into the sea,Copy !req
133. leaving long trails
of bubbles behind each diveCopy !req
134. Next to join the frenzy are the sharksCopy !req
135. Sharks get very excited
when dolphins are aroundCopy !req
136. That may be because
they can feed particularly...Copy !req
137. well once the dolphins have drivenCopy !req
138. the sardines into more compact
groups near the surfaceCopy !req
139. As the frenzy continues walls of
bubbles drift upwardsCopy !req
140. They are being released by the dolphins,
working together in teamsCopy !req
141. They use the bubbles to corral the
sardines into ever tighter groupsCopy !req
142. The sardines seldom cross the wall of
bubbles and crowd closer togetherCopy !req
143. Bubble netting in this way enables the
dolphins to grab every last trapped sardineCopy !req
144. Just when the feasting
seems to be almost over,Copy !req
145. a Bryde whale arrivesCopy !req
146. The survivors head on northwards,Copy !req
147. and the caravan of predators follows themCopy !req
148. Nutrients can also be brought upCopy !req
149. - though less predictablyCopy !req
150. — by rough weatherCopy !req
151. Particularly near the poles,Copy !req
152. huge storms stir the depths andCopy !req
153. enrich the surface waters and here,Copy !req
154. in the South Atlantic,
the seas are the roughest on the planetCopy !req
155. And very rich seas they are too, for here,Copy !req
156. the cold Falklands current from the SouthCopy !req
157. meets the warm Brazil
current from the NorthCopy !req
158. and at their junction
there is food in abundanceCopy !req
159. These Black-browed
albatross are duck-divingCopy !req
160. for krill that has been driven up
to the surfaceCopy !req
161. Like all albatross,Copy !req
162. Black-brows are wanderers
across the face of the open oceanCopy !req
163. A feeding assembly on this scale
is a rare sightCopy !req
164. Most of the time,Copy !req
165. the birds of the open sea
are widely dispersedCopy !req
166. But these feeding grounds are close
to an albatross breeding colonyCopy !req
167. - and a very special oneCopy !req
168. This is Steeple Jason, a remote island
in the far west of the FalklandsCopy !req
169. It has the largest albatross
colony in the worldCopy !req
170. There are almost half a million
albatross hereCopy !req
171. an astonishing demonstration ofCopy !req
172. how fertile the ocean can beCopy !req
173. and how much food it can give even to
creatures that do not actually live in itCopy !req
174. Nutrients by themselves are not enough to
generate these vast assemblies.Copy !req
175. The heat and light
that the sun brings everydayCopy !req
176. is also essential for the growth of
the microscopic floating plantsCopy !req
177. - the phytoplanktonCopy !req
178. And it the phytoplanktonCopy !req
179. that is the basis of all life in the oceanCopy !req
180. Every evening,
the disappearance of the sunCopy !req
181. below the horizon triggers the largestCopy !req
182. migration of life
that takes place on our planetCopy !req
183. One thousand million tones
of sea creaturesCopy !req
184. ascend from the deep ocean to
search for food near the surfaceCopy !req
185. They graze on the phytoplankton
under cover of darknessCopy !req
186. Even so, they are far from safeCopy !req
187. Other marine hunters follow them,Copy !req
188. some travelling up
from hundreds of metres belowCopy !req
189. At dawn, the whole procession returns
to the safety of the dark depthsCopy !req
190. The moon too has a great
influence on life in the oceansCopy !req
191. Its gravitational pull creates the daily
advance and retreat of the tidesCopy !req
192. But the moon has
more than a daily cycleCopy !req
193. Each month it waxes and wanes
as it travels around the earth,Copy !req
194. and this monthly cycle also
triggers events in the oceanCopy !req
195. The Pacific Coast of Costa Rica
on a very special nightCopy !req
196. It just after midnight
and the tide is coming inCopy !req
197. The moon is in its last quarter,Copy !req
198. exactly half way between full and newCopy !req
199. For weeks the beach has been empty
But that is about to changeCopy !req
200. At high tide,
turtles start to emerge from the surfCopy !req
201. At first they come in ones and twos,
but within a hour,Copy !req
202. they are appearing all along the beachCopy !req
203. They are all female Ridley turtlesCopy !req
204. and over the next six days or soCopy !req
205. four hundred thousand
will visit this one beachCopy !req
206. to lay their eggs in the sandCopy !req
207. At the peak time, five thousand
are coming and going every hourCopy !req
208. The top of the beach gets so crowded thatCopy !req
209. they have to clamber over one
another to find a bare patchCopy !req
210. where they can dig a nest holeCopy !req
211. A quarter of the world populationCopy !req
212. of Ridley turtles come to this one beachCopy !req
213. on a few key nights each yearCopy !req
214. The rest of the time, they are widely
distributed through the oceanCopy !req
215. searching for food, most
- a hundreds of miles away from hereCopy !req
216. This mass nesting is called an arribadaCopy !req
217. How it is co-ordinated is a mysteryCopy !req
218. - but we do know that's arribadas startCopy !req
219. when the moon is either in its first
or its last quarterCopy !req
220. Forty million eggs
are laid in just a few daysCopy !req
221. By synchronising their nesting in this wayCopy !req
222. the females ensure that six weeks laterCopy !req
223. their hatchlings
will emerge in such enormous...Copy !req
224. numbers that predators on the beachCopy !req
225. are overwhelmed
and a significant proportionCopy !req
226. of the baby turtles will get past them
and make it to the waterCopy !req
227. But why do the females
use a cue from the moonCopy !req
228. to help in synchronising their nesting?Copy !req
229. Part of the answer to that becomes clear
at dawn on the following morningCopy !req
230. The day shift of predators are arriving
for their first mealsCopy !req
231. Vultures have learnt
that the returning tideCopy !req
232. can wash freshly laid eggs out of the sandCopy !req
233. The risk of eggs being exposed by the surfCopy !req
234. may be part of the reason
why turtle arribadasCopy !req
235. tend to occur around the last
or first quarter of the moonCopy !req
236. It's on such days as this,
when the moon is neither full nor new,Copy !req
237. that the tides are weakest and
the sea is likely to be calmerCopy !req
238. So at these times,
it easier for the female turtlesCopy !req
239. to make their way through the surfCopy !req
240. and there less chance of their eggsCopy !req
241. being washed out of the sand
and being taken by the vulturesCopy !req
242. The moon monthly cycle
and its influence on the tides triggersCopy !req
243. many events in the ocean,
from the spawning of the coralsCopy !req
244. on the Great Barrier reef
to the breeding cycles of fishCopy !req
245. But there an even longer rhythmCopy !req
246. that has the most profound effect of allCopy !req
247. - the annual cycle of the sunCopy !req
248. The sun position relative
to the earth changesCopy !req
249. through the year and
it this that produces the seasonsCopy !req
250. In the north, spring comes as the sun
begins to rise higher in the skyCopy !req
251. Off the coast of North West America,Copy !req
252. the seas are transformed by the increasing
strength of the sunshineCopy !req
253. Here in Alaska the coastal waters turnCopy !req
254. green with a sudden bloom of phytoplanktonCopy !req
255. Herring that have spent
the winter far out to sea,Copy !req
256. time their return to the shallow waters
to coincide with this bloomCopy !req
257. They come in vast numbers and initiateCopy !req
258. one of the most productive
food chains in all the oceansCopy !req
259. Humpback whales are at the top
of that food chainCopy !req
260. They have spent the winter breeding
in the warmer tropical waters off HawaiiCopy !req
261. But there was little food for them thereCopy !req
262. This herring bonanza provides the vast
majority of their food for the yearCopy !req
263. Stellar and Californian sea lionsCopy !req
264. also return from the open ocean
each year to feast off the herringCopy !req
265. The herring themselves,
however, have not come here for foodCopy !req
266. They are about to breedCopy !req
267. Nothing deters them as they head
for even shallower watersCopy !req
268. Now the waters
are so shallow that glaucousCopy !req
269. - winged gulls are able to snatch live fish
from just below the surfaceCopy !req
270. In spite of these attacks and losses,Copy !req
271. the herring swim on untilCopy !req
272. they reach the vegetation that the femalesCopy !req
273. need if they are to layCopy !req
274. Each female produces
around twenty thousand eggsCopy !req
275. - and they every stickyCopy !req
276. The males arrive soon after the femalesCopy !req
277. have spawned and release their sperm
in vast milky cloudsCopy !req
278. Soon the excesses
of the herrings' sexual spreeCopy !req
279. creates a thick, white scum on the surfaceCopy !req
280. Through the season curds of sperm clog
the shores for hundreds of miles,Copy !req
281. from British Columbia in the South
all the way to Alaska in the northCopy !req
282. After a few days this gigantic spawningCopy !req
283. comes to an end and the herring head
back out to deeper waters,Copy !req
284. leaving behind them
fertilised eggs plastered...Copy !req
285. on every rock and strand of vegetationCopy !req
286. They time their spawning
so that two weeks later,Copy !req
287. when these eggs start to hatch,Copy !req
288. the annual plankton bloom
will have reachedCopy !req
289. its height and the new-born fish fryCopy !req
290. will have plenty to eatCopy !req
291. But in the meantime,
all these eggs provide foodCopy !req
292. for armies of different animals both below
and above the surfaceCopy !req
293. Millions of birds arrive to collect
a share of the herring bountyCopy !req
294. Some of it is easily gathered,Copy !req
295. for millions of eggs have been
washed up onto the shoreCopy !req
296. This encapsulated energy is particularly
valuable to migrating birdsCopy !req
297. These surfbirds are on their wayCopy !req
298. to their breeding grounds in the ArcticCopy !req
299. and they have to come down to refuelCopy !req
300. Stranded herring eggs
are just what they needCopy !req
301. Bonaparte gulls collect the eggs
just below the surface of the waterCopy !req
302. Further out in the bay,
huge flocks of ducks have gatheredCopy !req
303. They are mostly surf scotersCopy !req
304. - diving ducks - that can feed off
the bottom several metres downCopy !req
305. There are such huge quantities of eggsCopy !req
306. that even such a big animal as a bearCopy !req
307. finds it worthwhile to collect themCopy !req
308. The spawning of the herring
is a crucial eventCopy !req
309. in the lives of many animals
all along the coastCopy !req
310. The whole event coincides
with the plankton bloomCopy !req
311. and within just three short weeks
it all overCopy !req
312. The migratory birds leave
to continue their journey northCopy !req
313. They will not come back until
the herring also return next yearCopy !req
314. As the herring spawning finishes,Copy !req
315. other migrants are starting
to arrive just offshoreCopy !req
316. Grey whalesCopy !req
317. They have followed the sun northCopy !req
318. and they too are seeking the foodCopy !req
319. that is generated by
the bloom of the phytoplanktonCopy !req
320. Krill are feeding off it and these
whales are feeding on the krill,Copy !req
321. skimming it from the surface
with the filter plates of baleenCopy !req
322. that hang from their upper jawsCopy !req
323. Grey whales make one
of the longest migrationsCopy !req
324. undertaken by any marine mammalCopy !req
325. - a round trip of 12,000 miles orCopy !req
326. so from their breeding grounds off MexicoCopy !req
327. along the entire coast of North AmericaCopy !req
328. right up to the Arctic oceanCopy !req
329. They travel close to the coast
with the malesCopy !req
330. and non-breeding females leading the wayCopy !req
331. The last to start are the cows
that have just given birthCopy !req
332. They have to wait until
their new-born calvesCopy !req
333. are sufficiently big and strong to tackle
such an immense journeyCopy !req
334. Their progress is necessarily slowCopy !req
335. The mothers must stay
alongside their youngCopy !req
336. and even a strong calf can only travel
at a couple of knotsCopy !req
337. They stick even closer to the shoreCopy !req
338. often within just 200 metresCopy !req
339. Killer whales.Copy !req
340. They have learnt that grey whales
follow traditional routesCopy !req
341. The killers have no trouble in overtakingCopy !req
342. a calf and its devoted motherCopy !req
343. Normally,
they continually call to one another,Copy !req
344. but now they have fallen silentCopy !req
345. The mother grey whale and her calf
have no idea that they have been targetedCopy !req
346. Catching up with the grey whales
is the easy part for the killersCopy !req
347. They have to be cautious
for they are only...Copy !req
348. about half the size
of the grey whale motherCopy !req
349. She can inflict real damage with her tailCopy !req
350. But the killers are not after her
They are after her calfCopy !req
351. As long as the mother
can keep it on the move,Copy !req
352. it will be safe and
she does her best to hurry it alongCopy !req
353. At first the killers
avoid getting too close...Copy !req
354. to the mother but just keep pace alongsideCopy !req
355. They know that the calf,Copy !req
356. going at this speed, will eventually tireCopy !req
357. After three hours
of being harried in this wayCopy !req
358. the calf becomes too exhausted
to swim any furtherCopy !req
359. The mother has to stopCopy !req
360. This is the moment the killers
have been waiting forCopy !req
361. They start to try and force themselves
between mother and calfCopy !req
362. A calf, separated from its mother,Copy !req
363. will not be able to defend itselfCopy !req
364. Time and again the black finsCopy !req
365. of the killers appear between
the mottled backs of the grey whalesCopy !req
366. At last the killers succeedCopy !req
367. And now that they've got the calf
on its own, they change their tacticsCopy !req
368. They leap right on to the calf
and try to push it underCopy !req
369. They are trying to drown itCopy !req
370. The calf snatches a desperate breathCopy !req
371. The mother becomes increasingly agitatedCopy !req
372. Frantically,
she tries to push her calf backCopy !req
373. to the surface so that it can breatheCopy !req
374. But now it is so exhausted that it has
to be supported by its mother's bodyCopy !req
375. The killers won't give upCopy !req
376. Like a pack of wolves,
they take turns in harassing the whalesCopy !req
377. Now the whole pod is involvedCopy !req
378. One of them takes a biteCopy !req
379. Soon the sea is reddened
with the calf's bloodCopy !req
380. and the killers close in for the final actCopy !req
381. The calf is deadCopy !req
382. After a six-hour hunt, the killer whales
have finally won their prizeCopy !req
383. The mother, bereft, has to continue
her migration north on her ownCopy !req
384. She leaves behind the carcass
of a calf thatCopy !req
385. she cherished
for thirteen months in her wombCopy !req
386. for which she delayed
her own journey to find foodCopy !req
387. The pod of fifteen killer whales spent
over six hours trying to kill this calfCopy !req
388. But now, having succeeded,Copy !req
389. they have eaten nothing
more than its lower jaw and its tongueCopy !req
390. Valuable food like this will not
go to waste in the oceanCopy !req
391. Before long the carcass will sink
to the very bottom of this deep seaCopy !req
392. But even there,
its flesh will not be wastedCopy !req
393. Over a mile down in the
total darkness of the deep oceanCopy !req
394. - the body of another grey whale,
a thirty ton adultCopy !req
395. It settled here only a few weeks agoCopy !req
396. Already,
it has attracted hundreds of hagfishCopy !req
397. These scavengers, over half a metre longCopy !req
398. and as thick as your arm,
are only found in the deep seaCopy !req
399. They have been attracted
by the faint whiff ofCopy !req
400. decay suffusing through the water
for miles aroundCopy !req
401. With their heads buried
in the whale's flesh,Copy !req
402. they breathe through gill openings
along the sides of their bodiesCopy !req
403. They're very primitive creaturesCopy !req
404. - not even true fish, for they lack jaws.Copy !req
405. - They feed, not by biting, but byCopy !req
406. rasping off flesh
with two rows of horny teethCopy !req
407. In just a few hours,Copy !req
408. a hagfish can eat several times
its own weight of rotting fleshCopy !req
409. Next to arrive - a sleeper sharkCopy !req
410. It moves so slowly to conserve energyCopy !req
411. - an important strategy for so largeCopy !req
412. an animal surviving in such a poor habitatCopy !req
413. Sleeper sharks live over a mile downCopy !req
414. and grow to over seven metres longCopy !req
415. They can go for months without food,Copy !req
416. slowly cruising along the bottom,
waiting for rare bonanzas,Copy !req
417. such as this one, to arrive from aboveCopy !req
418. A whole range of different
deep-sea scavengersCopy !req
419. will feast on this carcass for a long timeCopy !req
420. before all its nutriment has been consumedCopy !req
421. Eighteen months later, all that is left
is a perfect skeleton, stripped bareCopy !req
422. The sun's energy that was capturedCopy !req
423. and turned into living tissue
by the floatingCopy !req
424. phytoplankton has been transferred fromCopy !req
425. one link to another in the food chainCopy !req
426. and has ended up as far away from the sunCopy !req
427. as it is possible to be on this planetCopy !req
428. - at the bottom of the deep seaCopy !req
429. But some energy also returns from the deepCopy !req
430. Millions of opalescent squid are
on their way to the shallowsCopy !req
431. They have come up here to mateCopy !req
432. As the males grab the females,
their tentacles flush redCopy !req
433. For most of the year these squidCopy !req
434. live at a depth of around 500 metresCopy !req
435. They only come together in these great
breeding schools for a few weeksCopy !req
436. Just one school was estimated to contain
animals that weigh around 4000 tonnesCopy !req
437. Wave after wave rise from the depthsCopy !req
438. and soon the seabed
in the shallows is strewnCopy !req
439. with dense patches of egg capsules
several metres acrossCopy !req
440. As each female adds
another capsule to the pileCopy !req
441. the males fight to fertilise its contentsCopy !req
442. The squid make their huge journeyCopy !req
443. into the shallows because their eggsCopy !req
444. will develop faster
in the warmer water hereCopy !req
445. and when the young emerge,
they will find moreCopy !req
446. food more easily than
they would in the ocean depthsCopy !req
447. Dawn the next morning and the seabed for
miles around is covered in egg capsules.Copy !req
448. The squid themselves have all goneCopy !req
449. Many will have died, but some will have
returned to their home in the deepCopy !req
450. They will not return
to the light of the sunCopy !req
451. until the next time they are driven up
by the urge to spawnCopy !req