1  
00:00:09,233 --> 00:00:13,066  
孤零零的一条鱼或许微不足道。  
Alone, a single fish may be insignificant.  

2  
00:00:16,233 --> 00:00:20,800  
但汇聚成群时，它们能决定整片海岸线的命运。  
But together, they can hold the fate of an entire coastline.  

3  
00:00:24,066 --> 00:00:26,742  
在深海中，数十亿沙丁鱼  
In the deep, billions of sardines  

4  
00:00:26,766 --> 00:00:29,609  
开始大规模迁徙...  
begin a mass migration...  

5  
00:00:29,633 --> 00:00:33,676  
由一丝凉水触发。  
Sparked by a whisper of cool water.  

6  
00:00:33,700 --> 00:00:38,876  
这是地球上最庞大的生物迁徙。  
It's the largest movement of living things on Earth.  

7  
00:00:38,900 --> 00:00:43,042  
而它即将成为自然界最宏大的伏击场。  
And it's about to become nature's greatest ambush.  

8  
00:00:48,300 --> 00:00:52,233  
沿岸所有掠食者都指望着这场盛会...  
Every predator along the coast is counting on this event...  

9  
00:00:54,300 --> 00:00:57,366  
...来享用沙丁鱼群带来的盛宴...  
...to feast on the abundance the sardines bring...  

10  
00:01:03,200 --> 00:01:06,042  
...在鱼群遁入深海之前。  
...before they slip away into the deep.  

11  
00:01:54,366 --> 00:01:56,376  
在非洲大陆最南端，  
Off the southern tip of Africa,  

12  
00:01:56,400 --> 00:02:01,033  
寒冷的南大西洋与温和的印度洋交汇。  
the frigid South Atlantic mixes with the milder Indian ocean.  

13  
00:02:03,566 --> 00:02:07,209  
这片海域寒冷且富含浮游生物，  
The waters are cold and rich with plankton,  

14  
00:02:07,233 --> 00:02:10,133  
由强大的大西洋上升流滋养。  
fed by upwellings from the mighty Atlantic.  

15  
00:02:13,033 --> 00:02:16,476  
是小鱼茁壮成长的完美环境。  
Perfect conditions for a tiny fish to thrive.  

16  
00:02:23,366 --> 00:02:27,809  
数十亿沙丁鱼常年栖息于此，  
Sardines by the billions live here year-round,  

17  
00:02:27,833 --> 00:02:30,776  
以数十万条为松散群体游弋觅食，  
swimming and feeding together in loose shoals  

18  
00:02:30,800 --> 00:02:33,600  
规模可达数十万条。  
of hundreds of thousands of individuals.  

19  
00:02:35,866 --> 00:02:40,809  
待到四月下旬，洋流开始微妙变化。  
Then in late April, ocean currents undergo a subtle shift.  

20  
00:02:47,266 --> 00:02:49,442  
随着南半球冬季临近，  
As the southern winter approaches,  

21  
00:02:49,466 --> 00:02:53,009  
上升流与漩涡推动一股寒流  
upwellings and eddies force a tendril of cold water  

22  
00:02:53,033 --> 00:02:56,442  
向东延伸。  
toward the east.  

23  
00:02:56,466 --> 00:03:00,142  
温暖的厄加勒斯洋流向远海偏移，  
The warm Agulhas Current moves further offshore,  

24  
00:03:00,166 --> 00:03:03,433  
使得寒流势力增强。  
allowing the cold stream to gain momentum.  

25  
00:03:05,833 --> 00:03:08,976  
喜寒的沙丁鱼本能地聚集在  
The cold-water sardines instinctively cluster  

26  
00:03:09,000 --> 00:03:10,842  
较冷的洋流中。  
in the chillier current.  

27  
00:03:16,133 --> 00:03:20,209  
在距岸150英里的厄加勒斯浅滩，  
150 miles out to sea, on the Agulhas Banks,  

28  
00:03:20,233 --> 00:03:22,800  
鱼群开始集结...  
schools begin to mass together...  

29  
00:03:24,566 --> 00:03:29,166  
...最终形成长达20英里的超级鱼群。  
...until they form a mega shoal 20 miles long.  

30  
00:03:32,466 --> 00:03:34,709  
随后这个巨型生命体  
Then the single superorganism  

31  
00:03:34,733 --> 00:03:37,476  
涌入寒流高速公路，  
pours into the cold-water highway  

32  
00:03:37,500 --> 00:03:40,400  
朝着海岸与浅水区进发。  
toward the coast and shallower water.  

33  
00:03:44,000 --> 00:03:47,676  
这是地球上最大规模的生物迁徙，  
It's the biggest biomass migration on the planet,  

34  
00:03:47,700 --> 00:03:52,209  
超越塞伦盖蒂的角马大迁徙。  
exceeding the great herds of the Serengeti.  

35  
00:03:52,233 --> 00:03:57,976  
但它们为何如此行动仍是个谜。  
Yet, exactly why they do it remains a mystery.  

36  
00:03:58,000 --> 00:04:01,666  
这段旅程对鱼群并无明显益处。  
The journey serves no apparent benefit to the fish.  

37  
00:04:04,233 --> 00:04:07,309  
它们终将止步于温暖的海洋——  
It will inevitably dead-end in a warm sea,  

38  
00:04:07,333 --> 00:04:09,500  
那并不适合沙丁鱼生存。  
unsuitable for sardines.  

39  
00:04:11,333 --> 00:04:14,376  
迁徙距离完全取决于今年寒流  
How far they travel depends entirely on the vagaries  

40  
00:04:14,400 --> 00:04:16,600  
的变幻无常。  
of this year's cold current.  

41  
00:04:18,666 --> 00:04:20,242  
但有一点可以确定...  
But one thing is certain...  

42  
00:04:20,266 --> 00:04:24,600  
整个食物链都指望着沙丁鱼的这场迁徙。  
an entire food web is counting on the sardines to make the run.  

43  
00:04:32,100 --> 00:04:35,800  
有些掠食者会跟随鱼群数周。  
Some predators will follow the shoal for weeks.  

44  
00:04:37,033 --> 00:04:40,966  
另一些则等待盛宴靠近海岸。  
Others wait for the feast to pass close to shore.  

45  
00:04:41,966 --> 00:04:45,466  
有些甚至疾驰数百英里前来拦截。  
Some even race hundreds of miles to intercept it.  

46  
00:04:54,600 --> 00:04:57,842  
对众多生物而言，今年的沙丁鱼迁徙  
To the multitude, this year's sardine run can mean  

47  
00:04:57,866 --> 00:05:01,866  
意味着丰足与饥馑的天壤之别。  
the difference between abundance and deprivation.  

48  
00:05:04,000 --> 00:05:06,800  
所有生灵都受制于洋流。  
All are at the mercy of the current.  

49  
00:05:12,000 --> 00:05:15,276  
若水温持续低于70华氏度（21℃），  
If the water temperature stays below 70 degrees,  

50  
00:05:15,300 --> 00:05:18,209  
沙丁鱼可能沿南非东海岸  
the sardines could travel 1,000 miles  

51  
00:05:18,233 --> 00:05:20,933  
跋涉1000英里。  
up the Eastern coast of South Africa.  

52  
00:05:22,333 --> 00:05:24,876  
但若寒流减弱，  
But if the tendril of cold water fades,  

53  
00:05:24,900 --> 00:05:29,576  
鱼群就会调头、分散或消失在深海中。  
the shoals will turn, disperse, or disappear into the deep.  

54  
00:05:38,633 --> 00:05:40,676  
海岸线在等待。  
The coastline waits.  

55  
00:05:45,233 --> 00:05:48,409  
鱼群面临的第一个危险  
The first hazard for the fish lies just 100 miles  

56  
00:05:48,433 --> 00:05:50,342  
距其栖息地仅100英里...  
from the sardine's home turf...  

57  
00:05:55,866 --> 00:05:59,833  
...一个约4000只南非毛皮海豹的聚集地。  
...a colony of some 4,000 Cape fur seals.  

58  
00:06:01,900 --> 00:06:03,509  
这些本地掠食者  
They're local predators,  

59  
00:06:03,533 --> 00:06:06,233  
在近岸浅水区巡逻。  
patrolling the shallows close to shore.  

60  
00:06:11,600 --> 00:06:14,766  
幼崽需要每四小时进食一次...  
The pups need milk every four hours...  

61  
00:06:17,100 --> 00:06:19,600  
...所以母海豹无法远行捕猎。  
...so moms can't go far to hunt.  

62  
00:06:27,400 --> 00:06:29,576  
它们也不愿离开近岸  
And they're reluctant to leave the safety  

63  
00:06:29,600 --> 00:06:31,633  
海藻林的安全地带。  
of coastal kelp forests.  

64  
00:06:34,100 --> 00:06:36,276  
高耸的海藻提供了  
The towering plants offer protection  

65  
00:06:36,300 --> 00:06:38,400  
抵御大白鲨的庇护所。  
from great white sharks.  

66  
00:06:40,533 --> 00:06:43,309  
若想享用沙丁鱼大餐，  
If the seals are to feast on sardines,  

67  
00:06:43,333 --> 00:06:47,142  
海豹需要鱼群主动送上门。  
they need the shoals to come to them.  

68  
00:06:47,166 --> 00:06:52,776  
母海豹依赖这些油脂丰富的鱼群来维持乳汁分泌。  
Mothers depend on the oily fish to fuel their milk supply.  

69  
00:06:52,800 --> 00:06:55,666  
而它们已怀上来年的幼崽...  
And they're already pregnant with next year's baby...  

70  
00:07:03,100 --> 00:07:06,366  
...当食物来源不稳定时，处境尤为艰难。  
...a precarious position when your food source is fickle.  

71  
00:07:10,666 --> 00:07:14,176  
聚集地拥挤不堪。  
The colony is crowded.  

72  
00:07:14,200 --> 00:07:16,366  
幼崽紧缠着母亲。  
Pups cling to mothers.  

73  
00:07:19,266 --> 00:07:20,900  
脾气变得暴躁。  
Tempers fray.  

74  
00:07:28,100 --> 00:07:31,300  
但今年，海洋给予了馈赠。  
But this year, the sea delivers.  

75  
00:07:35,233 --> 00:07:38,176  
寒流将浮游动物群推向  
The cold current pushes clouds of zooplankton  

76  
00:07:38,200 --> 00:07:41,433  
海岸和海豹聚集地。  
toward the coast and the seal colony.  

77  
00:07:44,200 --> 00:07:46,500  
小鱼追随食物...  
The little fish follow their food...  

78  
00:07:50,266 --> 00:07:52,942  
...径直进入海藻丛中。  
...directly into the kelp beds.  

79  
00:08:01,233 --> 00:08:04,076  
对海豹而言，这是一年中最珍贵的时刻。  
For the seals, it's the moment of the year.  

80  
00:08:12,933 --> 00:08:16,876  
它们的前肢宽大且力量惊人。  
Their front flippers are large and incredibly powerful.  

81  
00:08:20,966 --> 00:08:25,409  
如船桨般推动海豹以15英里时速前进。  
Like paddles, they propel the seals at 15 miles per hour.  

82  
00:08:31,766 --> 00:08:35,876  
在需要灵活机动时提供精准控制。  
And they provide control when maneuverability matters most.  

83  
00:09:09,566 --> 00:09:12,076  
每只海豹都协同作战。  
Every seal cooperates.  

84  
00:09:19,933 --> 00:09:22,366  
海豹会整条吞食沙丁鱼...  
The seals swallow fish whole...  

85  
00:09:24,766 --> 00:09:27,209  
...即使在水下也不例外。  
...even when they're underwater.  

86  
00:09:49,933 --> 00:09:55,142  
在猛烈攻击下，沙丁鱼群集结得愈发紧密。  
In the onslaught, the sardines school in an ever tighter mass.  

87  
00:09:55,166 --> 00:09:58,509  
这是经过验证的防御策略。  
It's a proven defense.  

88  
00:09:58,533 --> 00:10:01,309  
每条鱼都配备有侧线——  
Every fish is equipped with a lateral line...  

89  
00:10:01,333 --> 00:10:05,033  
头部、躯干和尾部的感觉细胞。  
sensory cells in its head, trunk, and tail.  

90  
00:10:06,466 --> 00:10:09,442  
其灵敏度足以感知  
It's sensitive enough to pick up the slightest change  

91  
00:10:09,466 --> 00:10:11,100  
最微弱的水压变化。  
in water pressure.  

92  
00:10:14,133 --> 00:10:17,009  
当某条鱼感知到邻居移动时，  
When a fish feels its neighbor move,  

93  
00:10:17,033 --> 00:10:19,866  
它会立即做出同步反应。  
it instantly responds in kind.  

94  
00:10:21,300 --> 00:10:26,209  
数百万次细微的同步动作合而为一，  
Millions of tiny, synchronized movements combine into one,  

95  
00:10:26,233 --> 00:10:29,142  
形成不断变形、  
forming a superorganism that shape-shifts  

96  
00:10:29,166 --> 00:10:31,533  
总能巧妙闪避的超级生命体。  
and slips just out of reach.  

97  
00:10:35,600 --> 00:10:38,576  
数千只饥饿海豹的围攻  
The assault by thousands of hungry seals  

98  
00:10:38,600 --> 00:10:41,266  
对巨型鱼群影响甚微。  
barely makes a dent in the giant shoal.  

99  
00:10:43,733 --> 00:10:46,342  
沙丁鱼群沿海岸继续逃逸，  
The sardines make their getaway up the coast,  

100  
00:10:46,366 --> 00:10:48,200  
海豹并未追击。  
and the seals don't follow.  

101  
00:10:50,566 --> 00:10:53,133  
它们需要回去喂养饥饿的幼崽。  
They need to get back to their hungry pups.  

102  
00:10:56,166 --> 00:11:00,009  
鱼群始终沿着寒流移动，  
The shoal always stays in the cold current,  

103  
00:11:00,033 --> 00:11:02,666  
每日行进可达40英里。  
covering up to 40 miles a day.  

104  
00:11:05,800 --> 00:11:09,733  
此刻雌鱼在沿海岸迁徙时产卵...  
Now the females drop eggs as they move up the coast...  

105  
00:11:11,466 --> 00:11:12,942  
...这使部分研究者认为  
...prompting some to suggest  

106  
00:11:12,966 --> 00:11:16,942  
这是年度产卵迁徙。  
that this is an annual spawning run.  

107  
00:11:16,966 --> 00:11:20,933  
另一些学者则认为纯粹是风力和寒流驱动。  
Others say it's simply driven by wind and cold water.  

108  
00:11:22,966 --> 00:11:27,200  
每前进一英里，水温都在不易察觉地升高。  
With each mile, the water grows imperceptibly warmer.  

109  
00:11:29,966 --> 00:11:33,109  
无人知晓具体何时何地，  
There's no telling where or when,  

110  
00:11:33,133 --> 00:11:36,676  
但寒流终将消散。  
but the cold current will eventually dissipate.  

111  
00:11:41,766 --> 00:11:45,909  
目前寒流依然强劲，推动鱼群继续前行。  
For now, it remains strong, impelling the fish onward.  

112  
00:12:07,600 --> 00:12:11,633  
五月初，沙丁鱼群接近另一处地标...  
By early May, the sardines approach another landmark...  

113  
00:12:13,666 --> 00:12:16,566  
距海豹聚集地以东400英里。  
400 miles east of the seal colony.  

114  
00:12:20,333 --> 00:12:21,942  
鸟岛。  
Bird Island.  

115  
00:12:28,000 --> 00:12:31,733  
这是全球最大的南非鲣鸟栖息地。  
It's the world's biggest colony of Cape gannets.  

116  
00:12:34,533 --> 00:12:36,342  
三个月来，这些鸟儿  
For three months, the birds have been  

117  
00:12:36,366 --> 00:12:38,576  
一直在哺育成长的幼鸟。  
feeding their growing chicks.  

118  
00:12:43,500 --> 00:12:46,009  
它们虽是凶猛的海洋掠食者，  
They may be fierce ocean predators,  

119  
00:12:46,033 --> 00:12:48,409  
但也是尽职的父母。  
but they're also devoted parents.  

120  
00:12:54,200 --> 00:12:55,476  
它们实行一夫一妻制，  
They're monogamous,  

121  
00:12:55,500 --> 00:12:58,609  
总会回到同一个巢穴。  
always returning to the same nest.  

122  
00:13:03,100 --> 00:13:04,509  
这里拥挤不堪。  
It's crowded.

123  
00:13:04,533 --> 00:13:07,542  
这意味着要争夺领地...  
That means competition for real estate...  

124  
00:13:07,566 --> 00:13:09,200  
和食物。  
and food.  

125  
00:13:16,766 --> 00:13:20,442  
这个栖息地有超过20万只鲣鸟，  
With over 200,000 birds in the colony,  

126  
00:13:20,466 --> 00:13:25,100  
一个繁殖季需要消耗9000吨鱼。  
they need 9,000 tons of fish in one breeding season.  

127  
00:13:36,033 --> 00:13:39,042  
鲣鸟将整个繁殖周期  
The gannets have pinned their entire breeding cycle  

128  
00:13:39,066 --> 00:13:42,366  
押注在难以预测的沙丁鱼到来上。  
on the unpredictable arrival of sardines.  

129  
00:13:50,400 --> 00:13:54,233  
侦察兵带着饱腹和好消息归来。  
Scouts return with full bellies and good news.  

130  
00:13:56,600 --> 00:13:58,576  
鱼群正在靠近。  
The fish are coming.  

131  
00:14:03,866 --> 00:14:07,966  
沙丁鱼超级群距海岸20英里...  
The sardine superorganism is 20 miles offshore...  

132  
00:14:10,666 --> 00:14:13,576  
...已进入栖息地的攻击范围。  
...within striking distance of the colony.  

133  
00:14:26,300 --> 00:14:30,542  
这些鸟儿在陆地上显得笨拙甚至滑稽。  
The birds appear awkward on the ground, even comical.  

134  
00:14:30,566 --> 00:14:35,476  
但一旦获得飞行速度，它们便展现出优雅与致命。  
But once they achieve air speed, they are all grace and danger.  

135  
00:15:02,500 --> 00:15:05,200  
它们翱翔在百英尺高空。  
They soar 100 feet in the air.  

136  
00:15:07,433 --> 00:15:10,542  
用双眼锁定鱼群...  
They scan the shoal with binocular vision...  

137  
00:15:26,000 --> 00:15:27,633  
...锁定目标...  
...lock on to a target...  

138  
00:15:29,700 --> 00:15:32,642  
俯冲而下。  
then dive.  

139  
00:15:36,766 --> 00:15:40,676  
鲣鸟以60英里时速扎入水中。  
Gannets hit the water at 60 miles per hour.  

140  
00:15:49,333 --> 00:15:52,542  
肌肉将颈椎牢牢固定。  
Muscles lock their neck vertebrae into place.  

141  
00:16:01,200 --> 00:16:04,709  
面部和胸部的气囊缓冲冲击力。  
Airbags in the face and chest absorb impact.  

142  
00:16:16,133 --> 00:16:20,309  
沙丁鱼向深处逃窜，  
The sardines swim deeper to escape,  

143  
00:16:20,333 --> 00:16:23,100  
但鸟类的冲力使它们能下潜...  
but the birds' momentum carries them down...  

144  
00:16:26,800 --> 00:16:30,576  
...至水下30英尺。  
...30 feet underwater.  

145  
00:16:30,600 --> 00:16:33,442  
若失手，鲣鸟会屏住呼吸  
If a gannet misses the target, it holds its breath  

146  
00:16:33,466 --> 00:16:37,209  
像企鹅般划水发起二次攻击。  
and paddles, penguin-like, for a second grab.  

147  
00:17:02,866 --> 00:17:05,842  
首轮捕猎全为幼鸟准备。  
This first hunt is all for the youngsters.  

148  
00:17:05,866 --> 00:17:08,076  
鲣鸟父母将食物储存在嗉囊，  
Gannet parents load up their gizzards  

149  
00:17:08,100 --> 00:17:11,166  
高速返回鸟岛。  
and return at high speed to Bird Island.  

150  
00:17:27,833 --> 00:17:31,900  
每对父母都精准记得幼鸟的位置。  
Every parent knows exactly where to find its chick.  

151  
00:17:52,600 --> 00:17:55,200  
这份食物补给弥足珍贵。  
The food cargo is precious.  

152  
00:17:58,066 --> 00:18:01,309  
健康的沙丁鱼迁徙意味着更多幼鸟  
A healthy sardine run means more young gannets  

153  
00:18:01,333 --> 00:18:03,442  
能获得生存机会。  
are given a chance to survive.  

154  
00:18:07,566 --> 00:18:09,177  
但  
But  

155  
00:18:07,566 --> 00:18:10,833  
这将是雏鸟最后的免费餐食。  
is the fledglings' last free meal.  

156  
00:18:09,201 --> 00:18:13,666  
此刻  
this  

157  
00:18:13,666 --> 00:18:17,766  
亲鸟将永远离开它们去追随鱼群。  
The parent birds will leave them forever and follow the shoals.  

158  
00:18:21,033 --> 00:18:22,709  
任何想要进食的鲣鸟  
Any gannet that wants to eat  

159  
00:18:22,733 --> 00:18:25,776  
都必须振翅追随鱼群。  
must get on the wing and follow the fish.  

160  
00:18:29,866 --> 00:18:33,009  
这成为雏鸟学习飞行的动力。  
This is motivation for the chicks to fly.  

161  
00:18:39,833 --> 00:18:43,109  
饥饿感越强，它们就越努力尝试。  
The hungrier they get, the harder they try.  

162  
00:18:52,633 --> 00:18:54,542  
学习曲线陡峭，  
The learning curve is steep,  

163  
00:18:54,566 --> 00:18:57,576  
要对抗呼啸的海风与怒涛。  
against howling wind and rough seas.  

164  
00:19:11,166 --> 00:19:14,466  
首次试飞便坠入浪中是必经考验...  
Crash-landing in the waves is their first pitfall...  

165  
00:19:22,466 --> 00:19:25,900  
但汹涌海浪并非真正的危险。  
but the wild surf is not the real danger.  

166  
00:19:28,300 --> 00:19:31,376  
毛皮海豹也在这片海岸狩猎。  
Fur seals hunt these shores, too.  

167  
00:20:22,300 --> 00:20:25,176  
雏鸟缺乏力量和经验  
Fledglings don't have the strength or experience  

168  
00:20:25,200 --> 00:20:26,776  
进行水上起飞。  
for a water take-off.  

169  
00:20:31,533 --> 00:20:33,976  
浸湿的羽毛让它们不堪重负。  
Soaked feathers weigh them down.  

170  
00:21:09,000 --> 00:21:13,142  
正如鲣鸟曾让沙丁鱼付出代价，  
Just as the gannets exacted their toll on the sardines,  

171  
00:21:13,166 --> 00:21:17,376  
如今鸟群自身也承受着损失。  
the bird colony now suffers its own losses.  

172  
00:21:59,100 --> 00:22:03,600  
幸运者必须晾干羽毛再次尝试。  
The lucky ones must dry their feathers and try again.  

173  
00:22:06,100 --> 00:22:10,142  
它们绝不能错过生命中的首次沙丁鱼狩猎。  
They can't miss out on the first sardine hunt of their lives.  

174  
00:22:45,700 --> 00:22:49,600  
沙丁鱼以每小时6英里速度东进。  
The sardines move east at 6 miles per hour.  

175  
00:22:52,200 --> 00:22:55,900  
它们正接近迁徙路上的首个真正险境。  
They're approaching the first real crux of their journey.  

176  
00:22:59,300 --> 00:23:04,009  
行进600英里后，海岸线向北转折，  
600 miles into the run, the coastline bends north,  

177  
00:23:04,033 --> 00:23:06,800  
大陆架开始收窄。  
and the continental shelf starts to narrow.  

178  
00:23:09,200 --> 00:23:12,576  
温暖的离岸洋流将寒流带  
Their cold-water ribbon is pinched against the coast  

179  
00:23:12,600 --> 00:23:15,266  
挤压向海岸。  
by warm offshore currents.  

180  
00:23:16,933 --> 00:23:19,076  
数十亿沙丁鱼必须挤进  
Billions of sardines must squeeze  

181  
00:23:19,100 --> 00:23:21,766  
这条逐渐收窄的寒冷通道。  
into the cold but narrowing channel.  

182  
00:23:25,533 --> 00:23:28,942  
鱼群被拉得更加细长。  
The shoal is stretched longer and thinner.  

183  
00:23:28,966 --> 00:23:31,209  
鱼群密度不断增加。  
The fish pack tighter together.  

184  
00:23:37,833 --> 00:23:42,266  
洋流将它们送往名为"狂野海岸"的区域。  
This current delivers them to a place called the Wild Coast.  

185  
00:23:44,300 --> 00:23:49,342  
这片200英里长的原始地带...是温带与热带生物群落  
It's a 200-mile stretch... A pristine, untouched transition  

186  
00:23:49,366 --> 00:23:52,442  
之间的纯净过渡区。  
between temperate and tropical biomes.  

187  
00:23:58,533 --> 00:24:01,509  
这里不仅是水温的交汇处，  
It's not only a mix of water temperatures,  

188  
00:24:01,533 --> 00:24:05,466  
更是无数物种的十字路口。  
it's also a crossroads for myriad species.  

189  
00:24:06,766 --> 00:24:10,142  
六月时节，从南极而来的座头鲸途经此地  
It's June and humpback whales pass from Antarctica  

190  
00:24:10,166 --> 00:24:12,309  
前往北方繁殖地。  
to breeding grounds farther north.  

191  
00:24:19,866 --> 00:24:22,242  
还有些物种常年栖息于此。  
Others live here all year round.  

192  
00:24:37,266 --> 00:24:41,909  
在鱼群前方50英里处，常驻的宽吻海豚  
50 miles ahead of the shoal, resident bottlenose dolphins  

193  
00:24:41,933 --> 00:24:43,800  
喜迎冬季来临。  
relish winter's arrival.  

194  
00:24:49,933 --> 00:24:54,100  
海豚以25只左右的社群为单位生活。  
Dolphins live in social groups of about 25 members.  

195  
00:24:58,533 --> 00:25:02,766  
它们的嬉戏揭示了其成为顶级猎手的原因。  
Their play reveals why they're such formidable hunters.  

196  
00:25:06,933 --> 00:25:10,042  
它们迅捷、善于交流、  
They're fast, they communicate,  

197  
00:25:10,066 --> 00:25:11,966  
且行动统一。  
and they move as a unit.  

198  
00:25:14,666 --> 00:25:17,733  
是沙丁鱼的天敌克星。  
A real-life sardine nemesis.  

199  
00:25:19,466 --> 00:25:22,642  
而这支常驻海豚群只是  
And this resident pod is just the advance guard  

200  
00:25:22,666 --> 00:25:24,833  
更庞大军团的前锋。  
for an even greater army.  

201  
00:25:34,766 --> 00:25:36,676  
真海豚群。  
Common dolphins.  

202  
00:25:44,733 --> 00:25:47,609  
它们多数时间生活在沿岸  
They spend most of their lives in warmer waters  

203  
00:25:47,633 --> 00:25:50,942  
较温暖水域。  
along the coast.  

204  
00:25:50,966 --> 00:25:54,866  
此时正值幼豚初学捕猎的季节。  
This time of year, their calves are just beginning to hunt.  

205  
00:25:57,333 --> 00:26:01,633  
母亲们需在明年春季繁殖季前完成断奶。  
Mothers need to wean them before next spring's breeding season.  

206  
00:26:03,333 --> 00:26:06,509  
充足的鱼群将是关键助力。  
A glut of fish would be a crucial windfall.  

207  
00:26:11,133 --> 00:26:15,976  
沙丁鱼未必会游经它们所在海域。  
There's no guarantee the sardine run will reach them.  

208  
00:26:16,000 --> 00:26:18,342  
于是它们主动出击。  
So they come to it.  

209  
00:26:24,066 --> 00:26:28,976  
南行途中，数百个家庭小群汇成大军。  
As they head south, hundreds of small family pods converge.  

210  
00:26:41,366 --> 00:26:44,309  
海豚超级群开始成形，  
A dolphin super pod begins to form,  

211  
00:26:44,333 --> 00:26:47,076  
奔袭拦截沙丁鱼群。  
streaming to intercept the shoal.  

212  
00:26:57,066 --> 00:27:02,609  
南方100英里外，鱼群沿狂野海岸涌进...  
100 miles to the south, the fish pour along the Wild Coast...  

213  
00:27:02,633 --> 00:27:04,900  
对前方危机浑然不觉。  
unaware of what lies ahead.  

214  
00:27:06,933 --> 00:27:10,409  
随着收窄的洋流将它们推向浅滩，  
As the narrowing current pushes them to the shallows,  

215  
00:27:10,433 --> 00:27:13,742  
鱼群开始分裂。  
the shoal fragments.  

216  
00:27:13,766 --> 00:27:19,542  
零散的饵球为鲨鱼提供了...  
Smaller, isolated bait balls offer a new opportunity...  

217  
00:27:19,566 --> 00:27:21,142  
新的机会。  
for sharks.  

218  
00:27:26,966 --> 00:27:30,209  
这些迁徙中的黑尾真鲨和灰三齿鲨  
These migratory blacktips and dusky sharks  

219  
00:27:30,233 --> 00:27:33,933  
从北方较暖水域南下而来。  
have moved down from the warmer waters farther north.  

220  
00:27:36,066 --> 00:27:38,342  
人们对它们的习性知之甚少，  
Little is known of their lives,  

221  
00:27:38,366 --> 00:27:41,376  
但附近发现的鲨鱼育幼场表明  
but shark nurseries have been discovered nearby,  

222  
00:27:41,400 --> 00:27:42,842  
这些鲨鱼...  
suggesting that the sharks...  

223  
00:27:42,866 --> 00:27:44,942  
如同沿岸其他生物...  
Like other creatures along the coast...  

224  
00:27:44,966 --> 00:27:48,566  
可能将繁殖周期与沙丁鱼迁徙同步。  
may time their breeding cycle to the sardine run.  

225  
00:27:52,300 --> 00:27:56,233  
小小鱼群与数十条鲨鱼正面对抗。  
Tiny fish face off with dozens of sharks.  

226  
00:27:59,700 --> 00:28:03,776  
看似实力悬殊...  
It seems an unfair match...  

227  
00:28:03,800 --> 00:28:07,009  
但沙丁鱼启动了集群防御。  
but the sardines launch their schooling defense.  

228  
00:28:17,933 --> 00:28:22,233  
鲨鱼游动时产生的水压波动，  
As the sharks move, they send a pressure wave through the water.  

229  
00:28:23,766 --> 00:28:27,533  
被鱼群敏感的侧线捕捉。  
The fish detect it through their sensitive lateral lines.  

230  
00:28:30,966 --> 00:28:33,476  
只要一条鱼闪避，  
Just one moves out of harm's way,  

231  
00:28:33,500 --> 00:28:36,409  
周围鱼群立即效仿。  
and every fish around it follows.  

232  
00:28:42,600 --> 00:28:44,709  
这套机制高效非凡。  
It's incredibly effective.  

233  
00:28:51,200 --> 00:28:54,242  
鲨鱼的转身撕咬总是慢半拍。  
The sharks simply can't turn and bite quick enough.  

234  
00:29:13,200 --> 00:29:16,076  
掠食者改变策略。  
The predators change tactics.  

235  
00:29:24,233 --> 00:29:27,809  
它们突然加速，试图将鱼群分割成  
With sudden bursts of speed, they try and carve the shoal  

236  
00:29:27,833 --> 00:29:30,166  
更小的饵球...  
into even smaller balls...  

237  
00:29:33,066 --> 00:29:35,809  
...但配合远不够默契。  
...but they just don't coordinate enough.  

238  
00:29:45,400 --> 00:29:49,109  
一群60磅重的金枪鱼加入战局。  
A school of 60-pound tuna gets in on the action.  

239  
00:29:53,200 --> 00:29:55,909  
通常鲨鱼以金枪鱼为食，  
Normally the sharks hunt tuna,  

240  
00:29:55,933 --> 00:29:59,100  
但此刻似乎懂得联手更有利。  
but they seem to know help when they see it.  

241  
00:30:00,300 --> 00:30:04,376  
体型较小的金枪鱼更为灵活。  
The smaller tuna are much more agile.  

242  
00:30:04,400 --> 00:30:08,709  
短短数秒内，它们就从鱼群中切分出饵球，  
Within seconds, they slice a bait ball from the shoal  

243  
00:30:08,733 --> 00:30:10,742  
将其逼至水面——  
and trap it against the surface,  

244  
00:30:10,766 --> 00:30:13,209  
让所有掠食者都能轻松进食。  
where it's easier for everyone to feed.

245  
00:30:37,800 --> 00:30:41,876  
掠食性鱼类与鲨鱼暂时休战，  
Game fish and sharks enjoy a temporary truce  

246  
00:30:41,900 --> 00:30:44,442  
共享同一批猎物。  
as they feast on the same prey.  

247  
00:31:34,166 --> 00:31:36,742  
主鱼群向北逃窜，  
The main shoal flees north,  

248  
00:31:36,766 --> 00:31:40,533  
留下这支残部任人宰割。  
leaving this fragment behind to be obliterated.  

249  
00:32:00,033 --> 00:32:02,776  
连海鸥也分得一杯羹。  
Even the gulls get their share.  

250  
00:32:30,400 --> 00:32:34,433  
巨型鱼群现已远离原生栖息地。  
The mega shoal is now way out of its home habitat.  

251  
00:32:36,533 --> 00:32:40,676  
只要寒流尚在，它们便盲目前行。  
As long as it's cold, they swim blindly along.  

252  
00:32:40,700 --> 00:32:43,842  
它们正逼近南非海岸的某个地标——  
They're heading toward a feature of the South African coast  

253  
00:32:43,866 --> 00:32:46,676  
这将成为它们旅程中  
that will prove the most consequential milestone  

254  
00:32:46,700 --> 00:32:50,176  
最具决定性的转折点...  
of their journey...  

255  
00:32:50,200 --> 00:32:53,809  
名为"瀑布崖"的砂岩岬角。  
A sandstone buttress called Waterfall Bluff.  

256  
00:33:00,733 --> 00:33:04,776  
这座石质海角迫使寒流向东偏转，  
This rocky promontory shoves the cold current eastward  

257  
00:33:04,800 --> 00:33:07,876  
与近岸暖流激烈碰撞。  
to collide with the warm water just offshore.  

258  
00:33:17,233 --> 00:33:23,009  
某些年份寒流能冲破这道屏障...  
Some years the cold water can blast beyond this point...  

259  
00:33:23,033 --> 00:33:24,509  
但今年例外。  
but not this year.  

260  
00:33:24,533 --> 00:33:27,500  
生命线般的洋流已细若游丝。  
The vital current thins to a trickle.  

261  
00:33:30,666 --> 00:33:35,033  
沙丁鱼如中魔咒般涌入狭窄水道。  
The sardines follow into the bottleneck as if spellbound.  

262  
00:33:37,466 --> 00:33:40,909  
每条鱼都遵循着相同使命...  
Every single fish follows the same mission...  

263  
00:33:40,933 --> 00:33:43,842  
紧跟鱼群，占据中心。  
Stick with the school and stay in the middle.  

264  
00:33:43,866 --> 00:33:46,076  
但在消退的洋流中，  
But in the fading current,  

265  
00:33:46,100 --> 00:33:50,276  
本就分裂的鱼群进一步瓦解。  
the already fractured shoal breaks up even further.  

266  
00:33:50,300 --> 00:33:54,309  
小股鱼群追随飘忽的冷水团  
Small schools follow shifting pockets of cool water  

267  
00:33:54,333 --> 00:33:55,966  
走向消亡。  
into oblivion.  

268  
00:34:00,000 --> 00:34:02,976  
伟大征程在此停滞，  
The great journey stalls for the fish  

269  
00:34:03,000 --> 00:34:06,376  
掠食者的完美猎场就此形成。  
and conditions align for every predator.  

270  
00:34:10,433 --> 00:34:13,900  
熟悉的敌人一路尾随至此。  
A familiar enemy has trailed them all this way.  

271  
00:34:16,000 --> 00:34:18,809  
部分鲣鸟不惜飞行24小时  
Some gannets will fly for 24 hours  

272  
00:34:18,833 --> 00:34:22,009  
前来围堵狭窄水道...  
to intercept the bottleneck...  

273  
00:34:22,033 --> 00:34:25,433  
沿岸栖息区更有大量援军待命。  
and there are plenty more roosting on the nearby coast.  

274  
00:34:28,033 --> 00:34:30,842  
这是对菜鸟们的真正考验。  
It's a true test for the rookies.  

275  
00:34:35,900 --> 00:34:38,366  
鲨鱼群也再度来袭。  
The sharks are back for more, too.  

276  
00:34:42,166 --> 00:34:45,442  
此前沙丁鱼总能通过舍弃  
Until now, the sardines have managed to slough off  

277  
00:34:45,466 --> 00:34:49,909  
小股饵球作为牺牲品脱身。  
small bait balls as sacrificial decoys.  

278  
00:34:49,933 --> 00:34:53,966  
但此刻它们已脆弱到极致。  
But now they're more vulnerable than they've ever been.  

279  
00:34:56,900 --> 00:34:59,409  
高空盘旋的鲣鸟最先发现  
The high-flying gannets are the first to spot  

280  
00:34:59,433 --> 00:35:01,076  
停滞的鱼群。  
a stalling shoal.  

281  
00:35:05,700 --> 00:35:08,042  
鸟群如天空中的信标，  
The birds stand out against the sky  

282  
00:35:08,066 --> 00:35:11,742  
为大军指引进攻方向。  
like a homing beacon, guiding in an army.  

283  
00:35:15,800 --> 00:35:17,800  
海豚超级军团现身...  
It's the dolphin super pod...  

284  
00:35:21,200 --> 00:35:25,309  
...规模已扩至两万之众。  
...now grown to 20,000 strong.  

285  
00:35:54,366 --> 00:35:57,809  
沙丁鱼正遭遇史无前例的围攻——  
The sardines now face an unprecedented assault  

286  
00:35:57,833 --> 00:36:01,409  
来自迅捷的远洋猎手舰队...  
from a fleet of swift ocean-going hunters...  

287  
00:36:08,100 --> 00:36:12,076  
...与高空集结的致命空军。  
...and a far-flung deadly air force assembling above.  

288  
00:36:52,833 --> 00:36:56,609  
沙丁鱼只能启动唯一已知的防御...  
The sardines turn to the only defense they know...  

289  
00:36:56,633 --> 00:36:59,776  
尽可能紧密集群。  
Schooling up as tight as they can.  

290  
00:37:04,000 --> 00:37:06,809  
一鱼动则全群动。  
One moves, and they all move.  

291  
00:37:22,233 --> 00:37:24,866  
但海豚早有应对之策。  
But the dolphins are prepared for this.  

292  
00:37:28,866 --> 00:37:32,376  
它们的目的是阻止鱼群下潜。  
Their goal is to prevent the shoal from diving deep.  

293  
00:37:37,800 --> 00:37:41,766  
协同封锁沙丁鱼的逃生路线。  
They coordinate their efforts, blocking the sardines' evasion.  

294  
00:37:44,833 --> 00:37:46,242  
以手术般的精度，  
With surgical precision,  

295  
00:37:46,266 --> 00:37:49,276  
将饵球从主群切割剥离。  
they slice balls away from the main shoal.  

296  
00:37:57,166 --> 00:38:01,476  
喷吐气泡圈禁任何试图突围的鱼...  
They blow bubbles to corral any fish that tries to break form...  

297  
00:38:07,466 --> 00:38:10,733  
...迫使鱼群越聚越密。  
...forcing the fish tighter and tighter together.  

298  
00:38:12,166 --> 00:38:14,309  
每条鱼都本能地试图  
Every fish instinctively tries to get  

299  
00:38:14,333 --> 00:38:16,033  
挤向群体中心。  
into the middle of the pack.  

300  
00:38:18,266 --> 00:38:22,109  
但疲惫的鱼鳃已难以从湍流中  
But now exhausted gills struggle to suck oxygen  

301  
00:38:22,133 --> 00:38:24,042  
汲取氧气。  
from turbulent water.  

302  
00:38:39,200 --> 00:38:43,933  
饵球接连被分解吞噬。  
Ball after ball is dissected from the shoal and obliterated.  

303  
00:38:45,700 --> 00:38:48,409  
海豚终得期盼已久的盛宴。  
The dolphins get what they've waited for.  

304  
00:39:24,600 --> 00:39:26,876  
伤亡呈指数级增长。  
The toll is exponential.  

305  
00:39:31,433 --> 00:39:34,809  
海豚的驱赶策略如此高效，  
The dolphins are so effective at herding the fish  

306  
00:39:34,833 --> 00:39:38,342  
使得其他掠食者也收获颇丰。  
that every other predator is also more successful.  

307  
00:40:09,200 --> 00:40:12,009  
当鱼群被逼至水面，  
As the fish are driven to the surface,  

308  
00:40:12,033 --> 00:40:15,442  
鲣鸟得以轻松捕食。  
gannets get easy access.  

309  
00:41:12,733 --> 00:41:16,209  
深色羽毛的雏鸟已如老手般狩猎。  
Dark fledglings now hunt like experts.  

310  
00:41:53,133 --> 00:41:55,976  
鲨鱼静候最佳时机  
Sharks follow and wait for the perfect moment  

311  
00:41:56,000 --> 00:41:58,633  
突袭密集的饵球。  
to cash in on the tight balls.  

312  
00:42:00,800 --> 00:42:03,033  
起初只在外围捡漏...  
They pick off the edges at first...  

313  
00:42:06,333 --> 00:42:08,009  
...继而长驱直入。  
...then they plough in.  

314  
00:42:22,933 --> 00:42:25,276  
海豚的攻势永不停歇。  
The dolphins are relentless.  

315  
00:42:31,666 --> 00:42:35,942  
幼豚首次学会捕鱼进食。  
Youngsters take the cue and feed on fish for the first time.  

316  
00:42:58,233 --> 00:43:03,109  
数英里海岸线上，所有掠食者同步猎杀。  
Along miles of coastline, every predator is synchronized.  

317  
00:43:18,800 --> 00:43:22,109  
形色各异的临时盟友  
Unlikely accomplices of all stripes work together  

318  
00:43:22,133 --> 00:43:24,509  
为共同目标协作。  
toward one brutal goal.  

319  
00:44:20,333 --> 00:44:22,376  
当鱼群精疲力竭、  
And then, with the fish exhausted  

320  
00:44:22,400 --> 00:44:25,642  
数千掠食者饱餐之后，  
and thousands of predators well fed,  

321  
00:44:25,666 --> 00:44:27,576  
终极猎手登场...  
the biggest arrives...  

322  
00:44:36,166 --> 00:44:39,176  
...20吨重的布氏鲸。  
...a 20-ton Bryde's whale.  

323  
00:44:43,200 --> 00:44:47,576  
一口吞噬数千沙丁鱼。  
Thousands of sardines gone in a single gulp.  

324  
00:45:07,833 --> 00:45:10,409  
这场盛宴持续数日。  
The feast goes on for days.  

325  
00:45:14,500 --> 00:45:17,509  
伟大鱼群已支离破碎。  
The great shoal is in tatters.  

326  
00:45:30,233 --> 00:45:34,166  
化作三英里长的自助餐台。  
It's now a 3-mile buffet.  

327  
00:45:40,900 --> 00:45:46,142  
混乱与疲惫使它们无法重组，  
Too confused and spent to reform their shoal,  

328  
00:45:46,166 --> 00:45:49,466  
距故乡已近八百英里。  
they're almost 800 miles from home.  

329  
00:46:00,233 --> 00:46:04,942  
消逝的洋流欺骗了它们。  
They've been duped by the vanishing current.  

330  
00:46:04,966 --> 00:46:09,566  
如今迷失在陌生暖海中四散飘零...  
Now they're lost and scattered in a strange, warm ocean...  

331  
00:46:12,100 --> 00:46:14,433  
...沦为他人盘中餐。  
...simply food for others.  

332  
00:46:17,400 --> 00:46:19,842  
然而厄运未止。  
And yet it isn't over.  

333  
00:46:23,933 --> 00:46:27,133  
掠食者之王降临。  
The predator of all predators arrives.  

334  
00:46:31,533 --> 00:46:33,242  
虎鲸。  
Orcas.  

335  
00:46:37,600 --> 00:46:41,009  
智慧与协作不逊真海豚，  
As smart and cooperative as a common dolphin  

336  
00:46:41,033 --> 00:46:43,133  
体型却是其三倍。  
and three times bigger.  

337  
00:46:46,133 --> 00:46:49,442  
虎鲸曾不为沙丁鱼迁徙而来，  
Orcas never used to travel for the sardine run,  

338  
00:46:49,466 --> 00:46:54,076  
如今却跋涉千里拦截鱼群。  
but now they swim thousands of miles to intercept the shoals.  

339  
00:47:04,333 --> 00:47:07,009  
但目标并非沙丁鱼。  
But it's not the sardines they're after.  

340  
00:47:16,966 --> 00:47:19,842  
它们是来猎杀海豚的。  
They're here to hunt dolphins.  

341  
00:47:29,400 --> 00:47:33,276  
猎手反成逃亡者。  
Not chasing anymore but running.  

342  
00:47:33,300 --> 00:47:35,876  
虎鲸不仅力量更强，  
The orcas are not only more powerful,  

343  
00:47:35,900 --> 00:47:37,776  
耐力也更胜一筹。  
they have more stamina.  

344  
00:47:45,366 --> 00:47:48,242  
正如海豚围猎鱼群，  
Just as the dolphins corralled the fish,  

345  
00:47:48,266 --> 00:47:51,233  
此刻虎鲸如法炮制。  
now the orcas work the dolphins.  

346  
00:47:55,833 --> 00:47:58,176  
它们将目标隔离出群。  
They isolate one from the pod.  

347  
00:48:09,800 --> 00:48:13,666  
锁定目标后轮番上阵...  
Once they've locked onto their target, they tag-team...  

348  
00:48:16,300 --> 00:48:17,876  
追逐...  
chasing it...  

349  
00:48:21,266 --> 00:48:24,609  
消耗...  
exhausting it...  

350  
00:48:24,633 --> 00:48:27,309  
...继而冲撞。  
then... ramming it.  

351  
00:49:11,066 --> 00:49:13,209  
它们反复攻击  
They attack again and again  

352  
00:49:13,233 --> 00:49:16,609  
直至海豚无力游动。  
until the dolphin can no longer swim.  

353  
00:49:41,700 --> 00:49:45,266  
大快朵颐前先令其窒息。  
Before they can feast, they drown it.  

354  
00:50:02,933 --> 00:50:06,500  
虎鲸冲散了海豚超级军团。  
The orcas have scattered the dolphin super pod.  

355  
00:50:08,700 --> 00:50:11,642  
失去海豚的围猎组织，  
Without the organizing force of the dolphins,  

356  
00:50:11,666 --> 00:50:17,133  
沙丁鱼重新集结潜入寒流深水。  
the sardines regroup and slip away into deep, cold water.  

357  
00:50:19,700 --> 00:50:23,442  
曾主宰海岸线的庞大鱼云  
The massive cloud of fish that dominated the coastline  

358  
00:50:23,466 --> 00:50:27,376  
如被大海吞噬般骤然消失。  
suddenly vanishes, as if absorbed by the sea.  

359  
00:50:35,133 --> 00:50:39,333  
七月尾声，餍足的猎手们四散离去。  
As July concludes, the sated hunters disperse.  

360  
00:50:42,166 --> 00:50:45,742  
鲣鸟每日飞行60英里  
Gannets proceed to travel up to 60 miles a day  

361  
00:50:45,766 --> 00:50:47,900  
继续觅食。  
searching for more food.  

362  
00:50:51,066 --> 00:50:53,909  
鲨鱼继续迁徙之旅，  
Sharks continue their migrations,  

363  
00:50:53,933 --> 00:50:56,476  
饱餐后更添力量。  
fully fed and stronger for it.  

364  
00:51:04,100 --> 00:51:08,076  
海豚成功完成幼豚断奶。  
Dolphins have successfully weaned their calves.  

365  
00:51:14,300 --> 00:51:17,909  
超级群落解体为家庭单位，  
Super pods thin out as family units regroup  

366  
00:51:17,933 --> 00:51:20,842  
回归常规猎场。  
and return to their regular hunting grounds.  

367  
00:51:25,100 --> 00:51:27,342  
寒流兑现了  
The cold current has delivered the feast  

368  
00:51:27,366 --> 00:51:29,833  
所有动物的生存赌注。  
that all the animals were counting on.  

369  
00:51:33,500 --> 00:51:38,176  
此刻它逐渐消散，融入温暖的印度洋。  
Now it fades away, mixing with the warm Indian Ocean.  

370  
00:51:45,100 --> 00:51:48,642  
有人认为沙丁鱼随洋流潜入深海  
Some believe the sardines ride the current down  

371  
00:51:48,666 --> 00:51:51,366  
秘密产卵。  
to secretly spawn in the deep.  

372  
00:51:52,866 --> 00:51:55,309  
也有人称它们原路折返，  
Others say they follow it all the way back,  

373  
00:51:55,333 --> 00:51:58,666  
跋涉千里回归好望角故土。  
1,000 miles to their home off the Cape.  

374  
00:52:01,633 --> 00:52:04,442  
来年寒流必将重生，  
Next year the cold current will reform,  

375  
00:52:04,466 --> 00:52:08,576  
或强或弱犹未可知...  
stronger or weaker than the last...  

376  
00:52:08,600 --> 00:52:10,076  
数十亿小鱼  
and billions of little fish  

377  
00:52:10,100 --> 00:52:13,042  
仍将追随它的召唤，  
will be driven to follow its call,  

378  
00:52:13,066 --> 00:52:19,209  
历经艰险与牺牲，奔赴未知的使命。  
to face hardship and sacrifice, toward a purpose yet unknown.  

379  
00:53:03,233 --> 00:53:04,942  
欲了解更多  
To learn more about what you've seen  

380  
00:53:04,966 --> 00:53:06,676  
本期《自然》节目内容，  
on this "Nature" program,  

381  
00:53:06,700 --> 00:53:09,042  
请访问pbs.org。  
visit pbs.org.