1 conservative 保守的
2 vessel
formal a ship or large boat
船；舰
•
a fishing vessel 渔船
3 saturated
In the early days, too, longlines would have been more saturated with fish.
逐句翻译
When prehistoric man arrived in new parts of the world, something strange happened to the large animals: they suddenly became extinct.
史前时代，当人类来到世界新的板块的时候，一些奇怪的事情发生在那些巨大的动物们身上：他们突然间就灭绝了。
当史前人类来到世界某个新地方的时候，一些奇怪的事情发生在那些巨大的动物们身上：他们突然间就灭绝了。
Smaller species survived.
而体型小的物种存活了下来。
The large, slow-growing animals were easy game, and were quickly hunted to extinction.
那些巨大的生长缓慢的动物们很容易成为猎物，他们被迅速地猎杀直至灭绝。
Now something similar could be happening in the oceans.
现在类似的事情要在海洋里面发生了。
That the seas are being overfished has been known for years.
多年来，海洋被过度捕猎已经众所周知了。
What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing.
像雷森 梅尔和鲍里斯 沃姆这样的研究者们展示的只是事情的转变有多快而已。
They have looked at half a century of data from fisheries around the world.
他们观察了半个世纪世界各地渔场的数据。
Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time.
他们的方法并没有尝试着在海洋特定的区域估计鱼群的真实总量（活的生物物种数量），而是关注于生物量随着时间的变化情况。
According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation.
根据他们在自然杂志上最新发表的论文，在新的渔场刚开发的15年里，大型捕食者（猎杀并吃掉其他动物的动物）的数量平均减少了80%
In some long-fished areas, it has halved again since then.
从那以后，在一些长时间捕鱼的区域，生物的数量又减半了。
Dr. Worm acknowledges that these figures are conservative.
沃尔姆博士承认这些数字还是保守的。
One reason for this is that fishing technology has improved.
导致数据保守的原因就是捕鱼的技术已经提升了。
Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago.
今天捕鱼船可以使用卫星和声呐系统寻找他们的捕猎目标，50年前可不行。
That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes.
那意味着有更高比例的海洋里的生物被捕捉，所以现在与过去的真实差别可能比根据抓捕数量的变化记录的差异更糟糕。
In the early days, too, longlines would have been more saturated with fish.
在早年间，长线本就能捕捉更多的鱼。
Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past.
在过去，可能会存在一些漏网之鱼，因为没有挂着诱饵的鱼钩来捕捉他们，这种情况会导致低估了过去的鱼群数量。
Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked.
更进一步的，在使用长线捕鱼的早年间，很多鱼在被勾住后又会被鲨鱼吃掉。
That is no longer a problem, because there are fewer sharks around now.
现在这不是一个问题了，因为现在鲨鱼变少了。
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account.
迈耶斯博士和沃尔姆博士认为他们的工作提供了一条基准线。未来的管理工作必须将这条基准线纳入考量中。
They believe the data support an idea current among marine biologists, that of the “shifting baseline”.
他们相信他们的数据支持了在当下海洋生物学家们中流行的观点，这个观点就是“动态基准线”。
The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past.
两位博士的提醒是，人类没有观察到已经发生在海洋里的巨大变化，因为过去人类只观察了一个相对较短的时间。
That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels.
这很重要。因为理论建议，从一个渔场持续捕捉的最大量是当该目标物种处于它原始生物量的50%的时候。
这很重要。因为“动态基线”理论建议，目标物种的生物量是初始水平的50%的时候，渔场能收获最大化的可持续产量。
Most fisheries are well below that, which is a bad way to do business.
大多数渔场都远低于50%，这是做生意的糟糕方式。
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