This Shark Is the Vertebrate Methuselah
格林兰鲨——脊椎动物中的长寿冠军

播音/撰文  辛西娅·格雷伯（Cynthia Graber）

翻译 bing

审校 吴非

Individual Greenland sharks appear to live perhaps a century longer than any other vertebrate, and might have life spans approaching 500 years.   
格陵兰鲨（Greenland sharks）可能要比其他脊椎动物至少长寿1个世纪，它们的寿命可能长达500年。

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.
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.
以人类标准来看，一些脊椎动物的寿命简直长得不可思议。某些乌龟活了近200年，而北极露脊鲸甚至可以多活10至20年。但现在，一个新的冠军登场了，它就是格陵兰鲨。保守分析，它已经在海里生存了大约3个世纪。尤利乌斯·尼尔森（Julius Nielsen）是哥本哈根海洋生物学的博士生。在格陵兰岛海域乘船进行考察时，他们意外地发现了格陵兰鲨，这引起了尼尔森的兴趣。

“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.”
“或许最大的疑团就是这些鲨鱼到底活了多久。通过观察，我们发现它们的生长速度极为缓慢，因此我们估计它们活了很长很长时间……所以他们的寿命可能是特别长的，但我们却无从调查。”

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.
因为格陵兰鲨的身体结构和大多数鱼类甚至其他鲨鱼都不同，所以没办法用相同的手段来估计年龄。因此，尼尔森和同事使用了一项新技术，根据鲨鱼的眼睛晶状体来判定它们的年龄。通过放射性碳年代测定分析晶状体的中心，可以得知这只鲨鱼是什么时候出生的。他们对28条雌性鲨鱼进行了检测。

“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.”
“在我们的分析中，一条体积最大的鲨鱼，也是最老的鲨鱼，活了将近390岁。”

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. [Julius Nielsen et al, Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)]
尼尔森强调，测量有很大的不确定性。虽然它最可能的年龄是390岁，但也有可能仅有272岁。“即使这样，格陵兰鲨也是目前所知的最长寿的脊椎动物。”这种鲨鱼的年龄上限有可能超过500岁。这项研究发布在《科学》（Science）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.”
另一个重磅消息是，研究人员估计鲨鱼在它们性成熟之前就已经活了1个世纪。“当然，对于人类来说，我们很难理解性繁殖为什么开始的这么晚。”

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.”
在论文中，尼尔森和同事强调要谨慎保护格陵兰鲨。“我们不知道格陵兰鲨的数量。但我们相信，当你知道它们需要100年才能变得性成熟时，你将对高捕获率和未来的商业开发非常敏感。”

With a century to do it, humans could inadvertently wipe out the entire next generation of these sharks during their long, slow adolescence.
—Cynthia Graber
还有一个世纪，在这些鲨鱼的长期缓慢的生长期内，人类很可能不经意地就把它们的下一代消灭掉。
—辛西娅·格雷伯（Cynthia Graber）