科学美国人60秒:This Shark Is the Vertebrate Methuselah

By human standards, a few vertebrate species have incredible longevity. Some tortoises live for nearly 200 years. Bowhead whales can live even a decade or two longer. But now there’s a new champion: the Greenland shark—which conservative estimates have swimming in the seas for almost three centuries.
按照人类的标准，有一些脊椎动物寿命非常的长。有些海龟可以活将近200年。弓头鲸可以活一二十年。但是人们发现了一个新的长寿王——格陵兰鲨鱼——保守估计，它们已经在海里生活了将近3个世纪。

Julius Nielsen is a marine biologist and PhD student at the University of Copenhagen. While on a research vessel in Greenland where such sharks were accidentally caught, Nielsen became curious about the creatures.
茱莉叶斯·尼尔森是一名海洋生物学家同时也是哥本哈根大学的博士生。在格陵兰的一艘科学考察船上，人们无意之间逮捕了格陵兰鲨鱼，尼尔森对这个生物充满的好奇之心。

“And perhaps the biggest of all the mysteries were how long do these sharks actually live. Because it has been expected that they can get very old, and that's based on some observations of very, very slow growth…so the longevity could be exceptional and extreme, but it has just never been possible to investigate.”
可能最大的谜团是格陵兰鲨鱼的寿命到底有多久。因为基于对格陵兰鲨鱼的观察，它们生长的非常的缓慢，所以它们的长寿现象也是非常的罕见的，但是调查其长寿的秘诀也并不是不可能的。

That’s because Greenland sharks don’t have the same body structures used for gauging the age of most fish or even other sharks. So Neilsen and colleagues used a new technique based on the lens of the eye. The centers of the lenses can be analyzed by radiocarbon dating to determine about when the shark was born. They tested 28 female sharks.
因为格陵兰鲨鱼不具备大多数鱼类甚至其他鲨鱼可以测量年龄的身体结构。所以，尼尔森和同事们采用了一项以眼睛晶状体为基础的新技术。人们可以通过放射性碳分析镜片的中心 来决定鲨鱼出生的时间。研究人员检测了28头雌性鲨鱼。

“And what we found was that the biggest shark in our analysis, and also the oldest shark, was estimated—the most likely single year age was almost approximately 390 years.”
研究发现，分析的最大的鲨鱼，同时也是最年长的鲨鱼，据估计，其最接近的年龄是390岁了。

Nielsen stresses that the estimate contains a fair amount of uncertainty. Though the likeliest age is 390, the shark could be as young as a mere 272. “That still makes the Greenland shark the longest-living vertebrate known to science.” And at the upper limit, it’s possible that the shark is more than 500 years old. The study is in the journal Science.
尼尔森强调该种预测包含很多的不确定性。尽管其最有可能是390岁，但看起来也就是272岁的样子。这是格陵兰鲨鱼成为迄今为止科学发现的最为长寿的脊椎动物。若往年长估计，该鲨鱼也可能已经500多岁了。该研究结果发表在《科学》杂志上。

Also shocking: the researchers estimate that the sharks live at least a century before they reach sexual maturity. “And of course it is absolutely amazing and difficult for a human mind to understand that sexual reproduction begins so late in life.”
同样，令人震惊的是：研究人员估计格陵兰鲨鱼至少要到100岁，才能达到性成熟。“当然按照人类的思考方式，很难理解性成熟以及繁殖交配如此晚。

In the paper Nielsen and his colleagues stress the importance of caution and conservation. “And the thing about Greenland sharks is just we don't know how many sharks are out there. But it's clear that if you reach sexual maturity above 100 years then you are potentially sensitive to any kind of high bycatch rate and any kind of future commercial exploitations.”
在文章中尼尔森和同事们强调了关心和保护格陵兰鲨鱼的重要性。“我们不知道还有多少格陵兰鲨鱼。但是如果在100岁以后才能达到性成熟 ，那么其对高捕捉率和未来的商业开发价值都是非常敏感的。”

With a century to do it, humans could inadvertently wipe out the entire next generation of these sharks during their long, slow adolescence.
在未来的一个世纪，在格陵兰鲨鱼漫长而缓慢的青春期内，人类可能一不小心就会将格陵兰鲨鱼的下一代给毁灭了。