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  3. Trawling (用拖网捕鱼) the seabed for fish is an environmental disaster; it wrecks ecosystems, destroys fish stocks and leaves behind

Trawling (用拖网捕鱼) the seabed for fish is an environmental disaster; it wrecks ecosystems, destroys fish stocks and leaves behind

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问题    Trawling (用拖网捕鱼) the seabed for fish is an environmental disaster; it wrecks ecosystems, destroys fish stocks and leaves behind a marine desert. Right? Environment campaigners say so. But there is growing evidence that the effect is sometimes very different, with trawling increasing fish stocks from the North Sea to the California coast. A new modeling study may for the first time have demonstrated why.
   Trawlers attach large nets to a metal beam dragged across the seabed to catch bottom-dwelling fish. Greenpeace compares it to "driving a huge bulldozer through a forest", leaving a flat, featureless desert on the seabed. Trawling clearly does remove fish, such as large crustaceans and shellfish, says Daniel van Denderen of the Wageningen Institute for Marine Resources and Ecosystem Studies in the Netherlands. But this is a lucky break for softer, smaller species lurking in the sandy seabed, such as worms. They survive and, with fewer rivals, flourish.
And if, as is often the case, these smaller critters are the main food for fish, then the overall effect is to nurture more marine life. Imants Priede, director of Oceanlab at the University of Aberdeen, UK, says there is growing evidence that—while far from universal—the phenomenon is real. "On continental shelves such as the southern North Sea, where shifting sands and gravels are stirred up by strong tidal currents, even trawling more than once a year may be beneficial for some fish stocks," he says.
   In fact, studies going back 20 years have linked persistent trawling with increased fish stocks. The cause of this counter-intuitive finding has remained uncertain. Some have suggested that trawling stirs up the seabed, throwing potential food into the water column—rather like ploughing a field. Others think that discards from fish nets add to the food available on the sea floor. But van Denderen is the first to show how trawling can stimulate fisheries simply by drifting from ecosystems. "The findings are very important," says Priede.
Which of the following statement is true according to the third paragraph?
选项 A、In the North Sea, trawling one or more times in a year is beneficial for fish stocks.
B、It is universal that trawling can increase fish stocks.
C、The area in which shifting sands and gravels are stirred up by strong tidal currents is beneficial for fish stocks.
D、Smaller critters help to nurture more marine life, because they are the main food for the fish.
答案D
解析 根据题干可以将该题定位至第三段。选项A对应着第三段的最后一句，但最后一句中描述的是southern North Sea，选项使用的是North Sea，可以排除。B选项指出trawling能增加鱼群种类是普遍的现象，但是第三段指出there is growing evidence that—while far from universal—the phenomenon is real，“这并不是普遍现象”，所以也排除B。C选项是一种强加因果，第三段在讲述shifting sands and gravels are stirred up by strong tidal currents时是对southern North Sea环境的描述，并不是认为这有利于鱼类的增加。D选项是对第三段第一句的同义转述，因此答案为D。
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