Models show that leaving sea cucumbers unharvested in some underwater zones for two years at a time stabilizes the overall population and actually increases yield for fishers.
Crop rotation is a recognized way to keep soil and the food ecosystem healthy. Now, scientists are saying that rotation could be a useful tool—in the sea.
Researchers tracked a shallow-water, near-shore species used for food: sea cucumbers. They’re easy to harvest and are fairly valuable. But those same attributes mean they’re easy to overharvest. The practice has put some sea cucumber species at high risk of extinction, even in a relatively well-managed area, the Great Barrier Marine Park in Australia.
In 2004 authorities split the Great Barrier Reef into 154 zones, where each zone was fished only once every three years. Fishers rotate through the region. In computer models, the researchers ran through dozens of simulations of each zone, both before and after the divisions took place. The trials revealed that even with an identical and low-catch allowance in all cases, the sea cucumbers would recover more fully under the rotation strategy than by harvesting simultaneously throughout the region. In fact, in trials that included rotations, the yield actually increased. The research is in the Proceedings of the National Academy of Sciences.
The scientists say their results suggest that such rotation might be beneficial in these kinds of shallow marine regions around the world, particularly for species that are in high demand. Because you should not eat your seed corn. Or your seed sea cucumbers.
疑难词汇：
Stabilize vt. 使稳固，使安定vi. 稳定，安定
Crop rotation轮作
Overharvest 过度采集
Cucumber n. 黄瓜;胡瓜
Extinction n. 消失;消灭;废止
Yield vt. 屈服;出产;放弃vi. 屈服，投降n. 产量;收益
长难句解析：
1. The scientists say their results suggest that such rotation might be beneficial in these kinds of shallow marine regions around the world, particularly for species that are in high demand.
难句类型：
That引导的定语从句+That引导宾语从句
句子主干：
The scientists say their results s
难句拆分：
The scientists say their results suggest that，The scientists say their results后面省略一个that引导的定语从句;suggest that，that引导的宾语从句。
2. In 2004 authorities split the Great Barrier Reef into 154 zones, where each zone was fished only once every three years.
难句类型：
Where引导的定语从句
句子主干:
In 2004 authorities split the Great Barrier Reef into 154 zones
难句拆分：
where each zone was fished only once every three years，Where引导的定语从句。
文本结构特点：
本篇文章主要讲的是海上轮作工作，这样的轮作方式增加了渔民的收入。海参就是一个很好的例子。所以海上轮作有很多好处可以满足人们的需求。
好了，以上就是前程百利小编为大家整理的备考托福听力背景材料以及专业词汇的学习。大家学会了吗?希望能在备考托福的路上助大家一臂之力。预祝大家取得好成绩。
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