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Narrator: Listen to part of a lecture in an Environmental Conservation class.
请听环境保护课上的部分内容。
Professor: Next I want to talk about the collapse of the North American Cod population.
教授：接下来我想讲一讲北美洲鳕鱼数量的爆减。
Let's look at Cape Cod in the northeastern United States.
我们来看看美国东北部的科德角吧。
The area was named Cape Cod because there was so many Cod fish in the waters just off its shores, so many that the first Europeans who fished there in the 17th century reported it was better than in New Finland, Canada.
这个地方被命名为科德角是因为那里海岸边的水域中曾经有很多鳕鱼，数量多到17世纪第一批在那里捕鱼的欧洲人报告说那里比加拿大的New Finland还要好。
At the time, New Finland's Cod fishery was so rich that people said it was possible just to lower a bucket in the water, pull it out and it would be full of cod.
在那时，New Finland的鳕鱼渔业非常丰富，以至于人们说直接把一个篮子放到水里然后把它拉出来里面就会装满鳕鱼也是有可能的。
But Cape Cod was even better, so the fishing industry there did great until after the 1940s, um, there were simply too many fishing vessels, sophisticated vessels, competing for fewer and fewer fish.
但是科德角还要更好，所以那里的捕鱼业发展得一直很好，直到二十世纪四十年代，那里的渔船太多了，都是很有经验的渔船来争抢越来越少的鱼。
In the 1940s there were still about four hundred million pounds of fish caught at Cape Cod every year.
在二十世纪四十年代，科德角每年仍有大约4亿磅的鱼被捕捞。
Just 50 years later, though, by the 1990s, commercial cod fishing there had become unprofitable.
但是，仅仅在50年后，也就是二十世纪九十年代，商业捕捞鳕鱼在那里已经无利可图了。
The annual catch had gone down about 5% of its 1940s' level.
年捕获量下降到了四十年代水平的5%左右。
And here's what's so fascinating: as more and more fishing vessels with better and better fishing technology were competing for cod, this competition was causing changes to the biology of the fish and these changes were making it more and more difficult for the cod population to sustain itself.
很令人着迷的是：随着越来越多的装配着越来越好的捕鱼技术的渔船争抢鳕鱼，这种竞争导致这种鱼产生了生物变化，而这些变化使得鳕鱼群越来越难维持自己的生存。
Student: Changes to the biology of the fish?
学生：这种鱼发生了生物变化？
Professor: Well, if a cod fish could reproduce earlier than usual, it'd have a better chance of passing on its genes to the next generation before being caught, right?
教授：如果一条鳕鱼能比平常早一些繁殖，那它在被抓之前就有更好的机会把自己的基因传给下一代，对吗？
And sure enough, biologists noticed that around Cape Cod, the cod were beginning to mature at an earlier age than normal.
果不其然，生物学家发现在科德角附近，鳕鱼在比一般更早的年纪开始成熟。
Prior to the population collapse, cod usually took about 8 to 10 years to fully mature, to start to reproduce, and they lived around 40 years total.
在数量爆减之前，鳕鱼通常需要8-10年的时间才能完全成熟，才能开始繁殖，而且它们总共能活40年左右。
So cod had about 30 years of active reproductive life.
所以之前的鳕鱼有大概30年的时间可以积极地繁殖后代。
But now, cod were beginning to reproduce at a younger age, at 3 to 4 years old, and they were living shorter lives because they were being caught, so they had fewer years within which to reproduce.
但是现在，鳕鱼在一个更年轻的年纪，在3-4岁的时候就开始繁殖，而且因为会被捕获，它们的生命也变得更短，所以它们能繁殖的年数更少了。
