第四集：鱼类
我们的地球是颗蓝色的行星 Ours is truly a blue planet.
水覆盖了大部分地球表面 Water covers most of the world's surface.
在这里我们是旁观者 Here we are the outsiders.
但碧波之下，有种生物却很兴盛 But under the waves one group thrives.
鱼类是水中高手 Fish are masters of the waters.
旗鱼又是所有鱼中最快的 And sailfish are the fastest of them all.
速度使它们成为海洋里最可怕的食肉动物之一 Their speed makes them one of the ocean's
most fearsome predators.
墨西哥海域，30条旗鱼包围着一群沙丁鱼 Off the coast of Mexico
要抓到猎物，不仅仅单靠速度 To catch their prey requires more than speed alone.
急转弯时，鱼鳍依旧结实 In the tightest turns
它们靠镰刀形的尾巴驱动前进 Their sickle-shaped tail powers them forwards
外形奇特的背鳍能够恐吓猎物 and that extraordinary dorsal fin helps intimidate their prey.
肉眼看来，它们的动作太快了 To the naked eye
慢镜头下，它们的战术才清晰呈现 slowed
选定一个目标非常困难 Just picking a target is hard enough.
通过敲打使它失去平衡，并将之从鱼群里孤立出来 Knocking it off balance
这需要极高的技巧 This requires extraordinary skill.
并非每次尝试都能成功 Not every attempt is successful.
但随着越来越多的旗鱼加入，一个失手，另一个迅速跟上 But as more sailfish join in
这群沙丁鱼被有条不紊地猎食殆尽 The shoal of sardines is methodically wiped out.
旗鱼是顶级猎食者，极少生物能威胁到它们 Sailfish are top predators
对大多数的鱼类来说，不是这回事 But for the majority of fish this is not the case.
开阔的海洋对它们是极度危险的 For most fish the open ocean is extremely dangerous.
有些能作出惊人之举，只为逃生 And some go to extraordinary lengths just to survive.
飞鱼 Flying fish.
靠超长的鳍，它们飞出水面 Free of the water they soar on elongated fins
将猎食者远远甩在后面 leaving their predators far behind.
鱼类的飞行家 A flight of fish.
飞鱼所面临的考验，不仅仅只是逃避天敌 Escaping predators is not the only test facing the
flying fish.
它们也必须保护发育中的后代 They must also protect their developing young.
飞鱼在寻找一种特殊的东西，使之成为可能 These flying fish are searching for the one thing
that will make this possible.
在如此辽阔的海洋里，并不容易 In such a vast ocean it's not easy.
它们很幸运 They're in luck.
一片棕榈叶 A palm frond.
海洋里漂流的微型岛屿 It's a tiny island adrift in a huge ocean.
它可以提供庇护所，但不是为飞鱼 And like an island it offers shelter
而是给它们的卵 but for their eggs.
雌鱼在叶子上产卵，雄鱼使它们受精 The females lay eggs on the raft
一条鱼的排卵会引发其它的鱼也开始排卵 The first fish spawn and this triggers the others to
start. 不一会儿，成千上万条鱼参与进来 Soon thousands join the melee.
产下难以计数的卵 Innumerable strands of eggs are laid.
重压之下“木筏”开始倾斜 The raft starts to tilt under their weight.
最佳产卵地点在叶子的中间 The best place to lay eggs is right inside the frond.
有些尝试被证明是失败的，它成了一些鱼的坟墓 For some the attempt proves fatal and living
fish become entombed.
在如此多鱼卵的重压下，它开始下沉 The raft starts to sink under the weight of so many eggs.
但这并非灾难 But this is far from a disaster.
沉到水面以下，实际上可以提高鱼卵的存活机会 Sinking away from the surface actually
improves the eggs' chances of survival.
在深处安全地躲避着，几天后 In just a few days
它们全都孵化出来 they'll hatch out.
其它的鱼则用不同的方式保护后代 Other fish protect their offspring in different ways.
有些在照料后代方面走的更远 Some go to far greater lengths to care for them.
澳大利亚南部的浅水区 The shallow waters of southern Australia
是许多奇异生物的家园 are home to many strange creatures.
童话般的海马王国 It's a fairytale world of sea horses...
占星鱼（一直瞪着眼看天空） ..stargazers...
鳐鱼 ..and stingrays.
但谁也比不上海藻龙的美丽 But none compare with the beauty of the weedy sea dragon.
它的背鳍快速地震动 The dragon's tiny fins beat frantically
防止自己被水流冲走 to prevent the current from sweeping it away.
现在是早春 It's the beginning of spring
海藻龙的求爱期开始了 the season when sea dragons begin their courtship.
在夜光下，它们开始跳舞 And in the evening light
在优美的二重奏里，一只龙能准确地模仿伴侣的动作 In a graceful duet
夜色很快就将这一对儿笼罩 Darkness will soon draw a veil over the pair
但它们会继续跳舞，直到深夜 but they will dance on
两个月后，它们的爱情结晶就会出现 Two months later
雄性海藻龙，它是携带着卵的那只 It's the male and he's the one that's carrying the eggs
一排一排的固定在它的尾巴上 with rows and rows of them embedded in his tail.
那一夜，雌性将卵移交给了它 That night the female transferred her eggs to him.
从那以后，它将独自照看这些卵 Since then
这样随身带着它们可以保证安全 By carrying them with him he's kept them safe.
现在，是它的付出得到回报的时候了 And now it's time for his efforts to be rewarded.
卵开始孵化 The eggs are ready to hatch.
在一个宁静的夏日早晨 In the calm of a summer morning
一个还带着卵囊小海龙诞生了 a baby sea dragon
海藻床为能够自己觅食的 The weed bed shelters older dragons
成年海龙提供庇护 that are already able to feed themselves.
尽管这些小海龙从父亲那里得到了很好的照料 Although these dragons were well cared for by
their father
如今，它们必须独自寻找食物 now they must find their own way in the world.
然而，还有一种鱼 There are fish 能够给后代提供更为长久的保护 which provide their young with a safe refuge for far longer.
太平洋西南部 The south western Pacific.
喷沙鱼（译者自命名） A convict fish
它是海底的建筑师 and it's something of a marine architect.
在地下制造了迷宫一样的通道 Underground it has created a labyrinth of tunnels.
成年鱼从来不敢从洞里出来，它吃什么仍旧是个谜 This adult never ventures out of its burrow
但它并非独住 But it doesn't live here alone.
另一个门口露出了许多小脸儿 At another entrance faces peer out.
幼年喷沙鱼 Juvenile convict fish.
不像成年鱼，这些小子不会被地洞所束缚 Unlike their parent
一旦它们现身，细流会变成洪水 And as they start to emerge
成千上万 There are thousands of them.
它们都帮助做家务 And they all help with the chores.
鱼多力量大 Many hands make light work.
它们在一起游动 The young fish swarm together.
上万张嘴吞食食物 Thousands of mouths gulping plankton.
成年鱼吃什么，应该跟这些小鱼有关 What the adults eat must somehow involve these
youngsters.
到底是小鱼们通过反刍来喂养大鱼呢？ Whether the young feed their parents by regurgitating
food
还是有其它的方式，我们无从得知 or through some other mechanism
无论答案如何，小鱼们给大鱼提供食物 Whatever the answer
它们的父母则提供庇护所作为回报 their parents with a meal and in return get a roof over their
heads.
繁衍后代只是一个挑战 Producing young is just one challenge.
寻找食物和居住场所，是鱼类必须面临的进一步考验 Finding food and somewhere to live are
further trials fish must face.
加利福利亚海岸，生存着大量的生物 The Californian coast
这也意味着生存空间的竞争异常激烈 But all this life means competition for living space is
intense.
老掉的贝壳是很宝贵的 Old shells are highly prized.
这个壳被一个怪头鱼（译者自命名）所占据 And this one is occupied by a sarcastic fringehead.
这种鱼非常的好斗 These fish are exceptionally quarrelsome
它们必须保护自己的住所 they have to be
一条章鱼 An octopus.
一不小心就进入了怪头鱼的地盘 Inadvertently it's wandered into the fringehead's territory
这是无法容忍的 and that can't be tolerated.
章鱼用特殊的腕足猛戳怪头鱼 The octopus's impressive jab holds the fringehead at bay.
这种行为远非坏脾气所能解释 There is more to this behaviour than being bad-tempered.
想要得到充足的食物，怪头鱼必须守住自己的场子 The fringehead needs to defend its patch if
it is to get enough to eat
章鱼就是个对手 and the octopus was competition.
蟹可不是那么好吞的 Crabs are not the easiest of mouthfuls.
由于生存空间狭小，这里总有不间断的领土纠纷 Because of the shortage of living space there