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解密海豚之死的“犯罪现场”调查员

更新时间:2018-5-29 21:17:06 来源:纽约时报中文网 作者:佚名

The crime scene investigators solving dolphin deaths
解密海豚之死的“犯罪现场”调查员

In a white-tiled lab at London Zoo, just across the street from the giraffes, two investigators are slowly and painstakingly dissecting a porpoise.

在伦敦动物园(London Zoo)长颈鹿馆区的街对面,有一座贴着白色瓷砖的实验室,两位调查员正小心翼翼地解剖一头鼠海豚。

Rescue workers recovered the stranded animal on a beach in Somerset a week before. It was maimed by brutal red gashes – from a boat’s propeller, they thought.

一个星期前,救援工作者在萨默塞特郡(Somerset)的一处海滩上找到了这头搁浅的鼠海豚。它身受重伤,几条红色伤口让人触目惊心。救援者认为,它是被船只的螺旋桨打伤的。

Investigators Rob Deaville and Matt Perkins are not so sure. Over the next two hours, they will try to uncover what killed this particular porpoise. They will also look for clues to a much bigger puzzle, one that involves all of marine life, answering questions like: what is the state of our oceans? What are the biggest threats? And what can we as humans do to help?

两位调查员迪维尔(Rob Deaville)和帕金斯(Matt Perkins)不愿轻易相信这样的结论。在接下来的两小时内,他们将设法查明这头鼠海豚的死因,并寻找线索去解开一个更大的谜团,这个谜团牵涉到所有海洋生物,解开它才能够回答下面这几个问题:我们的海洋处于什么样的状态?最大的威胁来自哪里?人类可以发挥怎样的作用?

Deaville and Perkins conduct post-mortems on more than a hundred porpoises, dolphins and whales a year for the Zoological Society of London. Their work has uncovered surprising threats, from long-banned chemicals lingering in the water to the devastating impact of fishing nets. But it has also revealed good news about the power of policy change and the return of endangered species.

应伦敦动物学会(Zoological Society of London)的要求,迪维尔和帕根斯每年都要对一百多头鼠海豚、海豚和鲸鱼进行验尸。他们发现了一些令人震惊的威胁,例如水中存有长期禁用的化学物质,渔网对海洋生物造成了灾难性的影响等等。但也发现了一些好消息,例如政策的改变开始显现效果,濒危物种的数量有所回升。

“We use a dead body on a beach to shed light on its life, not just its death,” says Deaville, who leads the UK’s Cetacean Strandings Investigation Programme – or CSIP for short – at the Zoological Society.

迪维尔是伦敦动物学会下设的英国鲸目动物搁浅调查研究项目(UK's Cetacean Strandings Investigation Programme,简称CSIP)的负责人。他说,"通过研究海滩上的动物尸体,我们不仅找到了这些动物的死因,还对其生活状况有了深入的了解。"

Cetaceans are dolphins, porpoises and whales, and the UK’s waters host an incredible range of them. About a quarter of the world’s known species have been found here, from bus-sized, singing humpback whales, to sleek, leaping bottlenose dolphins.

鲸目动物包括海豚、鼠海豚和鲸鱼,英国海域的鲸目动物种类之多令人惊讶。全球已知的鲸目动物中有四分之一的物种都在这一带出没过,比如有巴士大小、会发出声响的座头鲸,以及全身光滑、时常跃出水面的宽吻海豚。

Some 600 cetaceans wash up on UK shores every year. CSI scientists have systematically examined 4,000 of the strandings since 1990, more recently adding large sharks to their remit to deepen our understanding of sea life.

每年大约有600头鲸目动物被冲上英国的海滩。自1990年以来,鲸目动物搁浅调查研究项目的科学家们已系统性地研究了4000个搁浅案例,最近他们又将鲨鱼纳入其研究范围,以增进人们对海洋生物的了解。

In the lab, surrounded by intriguing jars labelled “penguin” and “mountain chicken”, Deaville and Perkins are taking a closer look at this particular porpoise’s wounds. The tools they use are basic – a scalpel, tweezers, a pair of garden shears – but having seen hundreds of bodies, they quickly form a view of how the porpoise died.

实验室里处处可见一些充满神秘感的瓶瓶罐罐,上面贴着"企鹅"和"山鸡蛙"的标签,迪维尔和帕根斯正在仔细检查这头鼠海豚的伤口。他们的解剖工具非常简单,仅仅是解剖刀、镊子和园林剪刀。但因为有之前解剖过几百具动物尸体的经验,他们很快就对鼠海豚的死因有了自己的看法。

The injuries are too shallow for propeller damage; pecking seagulls are probably to blame. Deaville gently slices off a strip of skin and blubber to be tested later for accumulated chemicals. A putrid, rotten smell rises from the body. I realise now why I was asked before the post-mortem if I had a strong stomach, and warned that some observers faint.

伤口太浅,不像是螺旋桨弄伤的;倒有可能是被海鸥啄伤的。迪维尔从鼠海豚尸体上轻轻切下一块皮肤和脂肪,以便稍后检验其中累积的化学物质。尸体散发着腐臭味。我现在明白了,为什么在做尸检之前别人会问我是否有很强的能力承受恶心反胃的感觉,以及为什么别人会提醒我一些检测人员曾在验尸时晕倒。

“As we’ll go through this, you’ll see a lot of similarities between us and them, because they are mammals,” Deaville says as he lifts out the dark purple liver. “But you’ll see differences as well.”

迪维尔一边取出深紫色的鼠海豚肝脏,一边说,"验尸时你会发现我们和这些鲸类之间有很多相似之处,因为它们也是哺乳动物。但也有不同点。"

The most obviously familiar features are the porpoise’s eyes. They are dog-like and friendly-looking, not flat and glassy like those of fish. But soon, more curious traits emerge. Porpoises have multiple stomachs, like cows, and are indeed related to them. They don’t have two large kidneys, but hundreds of tiny ones. Their adrenal glands tend to be enlarged, possibly because life as a porpoise is rather stressful. They are smaller than dolphins and whales and face many predators, including seals, who can pull them down by their tails and drown them.

很显然,鼠海豚最为熟知的外貌特征是眼睛——和狗很像,看上去非常友好,不像鱼眼睛那样扁平呆滞。不过鼠海豚还有更有趣的特征。鼠海豚和牛一样有好几个胃,而且两者的胃有很多相关之处。鼠海豚没有两个大型肾脏,但却有几百个小型肾脏。鼠海豚的肾上腺往往比较肥大,这可能与其艰辛的生活有关。鼠海豚的体型小于海豚和鲸鱼,且有很多天敌,比如海豹。海豹可以抓咬住鼠海豚的尾巴将其拖至水下,使其溺亡。

Added to these natural threats are the man-made ones. The main killer of sea mammals in the UK is bycatch – that is, unintended entanglement in fishing nets and lines. They suffocate in the nets and often sustain terrible injuries, losing flippers or breaking bones as they try to wriggle free.

除了自然威胁之外,还有人为的威胁。在英国,海洋哺乳动物的主要死因是误捕,渔网和钓线会无意中将其缠绕。海洋哺乳动物在渔网中呼吸困难,企图挣脱渔网时常常会失去鳍肢或骨折,从而造成重伤。

“Bycatch is a very unpleasant way to die,” says Sarah Dolman, senior policy manager at Whale and Dolphin Conservation, a charity that campaigns for better protection of cetaceans. I call Dolman after the post-mortem – or necropsy, as it is properly called – to hear more about this clash between our appetite for fish and the cetaceans’ fight for survival.

鲸豚保护协会(Whale and Dolphin Conservation)的高级政策专员窦曼(Sarah Dolman)说:"遭误捕是一种非常痛苦的死亡方式。"该协会是一个慈善机构,一直呼吁让鲸目动物得到更好的保护。验尸(准确地说是尸体剖检)之后,我采访了窦曼,对于人类的贪婪和鲸目动物的生存挣扎之间的矛盾有了更深了解。

Both Dolman and Deaville are quick to point out that no fisherman wants to catch a dolphin, as dolphins are a protected species along with whales and porpoises. Indeed, a 2017 report for the UK government notes fishermens’ high levels of compliance with EU regulations on reducing bycatch. These include the use of ‘pingers’ that emit a sound that drives porpoises away. But even with these measures, more than 1,000 harbour porpoises were estimated to have died in nets off the UK’s coast in 2016 alone – and that just covers the UK fleet.

窦曼和迪维尔很快指出,没有渔民想捕海豚,因为它们都是保护动物。英国政府2017年的一份报告显示,渔民非常遵守欧盟减少误捕的法规,其中一项为使用"声波发生器"发射声波来驱赶鼠海豚。但即便有了这些措施,据估计,仅在2016年就有1000多头港湾鼠海豚在英国近海的渔网中丧生,这还只是英国渔船的相关数字。

One of the difficulties in reducing bycatch is the UK’s astonishing marine diversity. The range of different species here – not just dolphins and whales, but also sea birds – and many different types of fishing gear mean that no single solution will work.

减少误捕的一个难点在于英国海洋生物种类惊人的丰富。除了鲸鱼、海豚,还有海鸟,再加上各式各样的渔具,这些都使问题不可能仅有单一的解决方案。

In Scotland, for example, about half of minke whales that wash up dead were entangled in the fishing lines of pots for catching lobster, langoustines or crabs. Humpback whales even have been spotted dragging fishing gear with them through the sea. Off the coast of southern England, hundreds of common dolphins are caught in ordinary fishing nets every year.

例如在苏格兰,被冲上海滩的小须鲸约有一半是被捕渔罐的丝线缠绕致死,而这些捕鱼罐原本是用来捕龙虾、挪威海螯虾或螃蟹的。人们甚至曾经目睹座头鲸身上缠着渔具游来游去的情景。在英格兰南部海域,每年都有数百头海豚落入普通渔网。

Meanwhile, my shopping habit of checking tuna tins for the ‘dolphin-friendly’ label may not be as helpful as I thought. Dolphin-friendly means the fishing fleet makes an effort to avoid dolphins, but they may still accidentally catch them. The only way to really avoid bycatch is to buy hand-caught ‘pole-and-line’ fish, according to Dolman – meaning when fishermen pull their catch out of the water one by one. Still, she remains hopeful: “Bycatch is not an easy problem to solve, but it’s solvable.” She believes the UK’s strategy to reduce bycatch could pay off in the next few years.

我买金枪鱼罐头时有个习惯,即检查包装上的"对海豚友好"标签,但这并没有我想象中的那样奏效。对海豚友好的渔船设法避开海豚,但还是会时不时地捕到海豚。窦曼表示,真正能避免误捕的唯一办法就是消费者只购买用"鱼竿和鱼线"方式捕来的鱼,即渔民从水里一条一条钓上来的鱼。她仍然充满希望地表示:"要解决误捕问题并不容易,但我们一定能找到解决办法。"她相信英国在减少误捕方面制定的策略在接下来几年里会收到成效。

“I think we’re in a very positive place in UK,” she says. “It’s high on the political agenda, and there’s a lot of public support.”

"我相信在英国我们有非常好的时机,"她说。"这个事情成为了很重要的政治议题,而且赢得了非常多的公众支持。"

The porpoise in the lab did not die in a net. About an hour into the inquest, Deaville has taken apart its liver, lungs, stomach and ovaries, and determined that the animal is young, female and rather undernourished. He found parasites, some abscesses and a stomach ulcer. He suspects that she may have suffered from an infection that left her too weak to hunt. Or perhaps she could not find enough food, and in her weakened state caught an infection.

实验室里的这头鼠海豚并非死于渔网。经过一小时的尸检,迪维尔将鼠海豚的肝脏、肺、胃和卵巢从其体内分离出来,并推断这头动物处于青年期,性别为雌性,而且严重营养不良。他在鼠海豚体内发现了寄生虫,一些脓肿和一块胃溃疡。他猜想她当时可能患上了传染病,身体非常虚弱从而无法捕猎;也有可能是因无法觅得足够的食物而身体虚弱,进而患上了传染病。

The exact cause of death is often difficult to establish, but even a slightly inconclusive necropsy can yield fascinating results.

确切的死因常常难以查明,但即便是这样一个不那么具有说服力的尸体剖检也能得出一些耐人寻味的结果。

Perhaps the most surprising finding is the presence of a long-banned toxic flame-retardant known as polychlorinated biphenyls, or PCBs, in stranded whales, dolphins and porpoises. Outlawed in the 1980s, PCBs still seep into the sea from landfill sites.

也许最让人意外的是,人们在搁浅的鲸鱼、海豚和鼠海豚的身体中发现了一种长期禁用的毒性阻燃剂,即多氯联苯(polychlorinated biphenyl)。虽从20世纪80年代起,使用多氯联苯已属非法,但此种物质仍然从垃圾填埋点渗入海洋。

They have been linked to infertility in sea mammals, and are thought to be driving the last pod of orca whales in Scotland into extinction: only eight of the distinctive black-and-white whales remain. Last year, the stranded body of one, nicknamed Lulu, was described as “one of the most contaminated animals on the planet” in terms of its PCB load.

多氯联苯可以导致海洋哺乳动物不育,人们认为生活于苏格兰海域最后几头虎鲸正因此走向灭亡:目前这种体色黑白分明的鲸鱼在苏格兰海域仅剩八头。去年,一头别名"璐璐(Lulu)"的搁浅虎鲸因其体内多氯联苯含量之高而被称为"地球上受污染最严重的动物之一"。

“It’s a really sad situation,” says Dolman. “They’re not having youngsters, so they’re probably going to die out.”

窦曼说,"这种情况导致它们无法生育,因此极有可能灭绝,情况令人痛心。"

On the upside, Deaville’s work has shown that policy change can be remarkably effective. One study on the blubber of harbour porpoises found that levels of PBDE, another toxic flame retardant, have fallen since the compound was phased out in the 2000s. And a moratorium on whaling has prompted a rise in the number of humpback whales – which also means more of them wash up.

从好的方面来看,迪维尔的工作表明政策改变非常有效。一项对港湾鼠海豚脂肪的研究发现,另一种毒性阻燃剂多溴二苯醚(PBDE)在其体内的含量水平已经下降,因为该化合物在21世纪的开始几年已被逐步禁用。捕鲸活动的暂停也使座头鲸的数量有所回升,当然这也意味着会有更多的座头鲸被冲上海滩。

“Strandings are not always bad news,” Deaville says. “It’s the species we don’t see that we worry about.”

迪维尔说,"搁浅也并不算是坏消息,如果那并非珍稀物种的话。"

The necropsy is almost over. Last, we inspect the inside of the porpoise’s head, including the parts that facilitate so-called echolocation – the cetaceans’ famous ability to hunt guided by sound alone. The remains are dropped into yellow plastic bags to be incinerated later.

尸体剖检差不多要结束了。最后我们来检查鼠海豚的头颅内部,其中一些结构可以进行回声定位。鲸目动物以这项能力著称,仅凭声波便能捕猎。尸体的其余部分放进黄色塑料袋,随后将被焚化。

I leave the lab and return to the outside world, passing blossom-covered trees and chattering groups of schoolchildren, while thinking of the drama that unfolds along our shores every day – unseen and unnoticed, until a body on a beach reveals it all.

我离开实验室回到外面的世界,从鲜花盛开的树木和熙熙攘攘成群结队的学童旁边路过,脑海中浮现出海滩上每天上演的场景——没人看见,没人注意,直到一具尸体出现,道尽所有一切。

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