Decline of Big Fish Upsets Ocean Balance

    By 2050, small fish could dominate(控制支配) the oceans because of the rapid decline of larger, predator¹ fish.
    In a new report, the U.N. Food and Agriculture Organization finds that one-third of the world’s fisheries are overexploited, depleted³ or recovering and in urgent need of rebuilding. At a recent meeting of the American Association for the Advancement⁴ of Science meeting in Washington, University of British Columbia fisheries expert Villy Christensen predicted the eventual⁵ preponderance of small fish.
    Twenty years ago, Christensen designed a computer tool called Ecopath to study complex marine⁶ ecosystems⁸. Now Ecopath has 6,000 users in 155 countries.
    Christensen used 200 marine models from the Ecopath database for the analysis released at the Washington meeting. "We are estimating(估计估算) that the predatory fish, the large fish that eat other fish, have declined by two-thirds in the 100 years and the decrease is accelerating. In the last 40 years alone, 54 percent of that decline occurred."Over the same 100-year period, Christensen says, prey⁹ fish like anchovies¹⁰, herring and sardines¹¹ have more than doubled. "We’ve never had numbers like that before. We expected it might be the case, now we have numbers documenting it. What has happened here really is that we’ve changed the wild ocean. We’ve removed the big fish."More prey and fewer predators¹² could throw the ecosystem⁷ out of balance, Christensen says. That could promote the growth of alga blooms which deplete² oxygen in the water column. Christensen fears that marine animals and plants would then begin dying off in huge numbers.  "If we look ahead we are going to see less stable ecosystems in the oceans. There would be forage¹³ fish and very few of the organisms that control our ecosystem. We need the predators to keep the populations healthy of all the prey fish. That will continue unless we change the way we manage the oceans."What’s driving these trends? Jacqueline Alder¹⁴, coordinator¹⁵ of the Marine and Coastal¹⁶ Ecosystem Branch of the United Nations Environment Program, believes it is overfishing and pollution, complicated by global climate change. She says the future health of the ocean depends on fishing less, reducing wasteful¹⁷ by-catch, and taking action on multiple threats to marine ecosystems.
    "We need to think about expanding our marine protected area systems and also better management of those systems, reducing pollution, reducing the amount of nutrients¹⁸ coming in, including things like agricultural runoff." Alder adds that managers must consider restoring mangroves and coral reefs, "making it so those nursery ecosystems have fish that will grow up into adults that will be available for the fishing community in 2050."Fish now provide more than three billion people with at least 15 percent of their animal protein diet. According to the U.N. Food and Agriculture Organization, fish farms are set to overtake wild ocean catch as the primary source of food fish. Villy Christensen says the aquaculture industry currently relies on a variety of prey fish to feed its farm-raised species and that practice is not conducive¹⁹ to a healthy ocean. "Instead of fishing down the food web we have to eat down the food web. We need to eat the sardines and anchovies."Christensen suggests that by changing our eating habits - eating more prey than predators - we could help restore a more healthy balance to the ocean ecosystem.(本文由在线英语听力室编辑整理)

1 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

2 deplete   

v.弄空，排除，减轻，减少...体液，放去...的血

参考例句：

• Most native mammal species have been severely depleted.大多数本地哺乳动物的数量都已经大大减少了。
• Elastic collisions deplete very little of the electron's energy.弹性碰撞中电子减少的能量非常少。

3 depleted   

adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词

参考例句：

• Food supplies were severely depleted. 食物供应已严重不足。
• Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。

4 advancement   

n.前进，促进，提升

参考例句：

• His new contribution to the advancement of physiology was well appreciated.他对生理学发展的新贡献获得高度赞赏。
• The aim of a university should be the advancement of learning.大学的目标应是促进学术。

5 eventual   

adj.最后的，结局的，最终的

参考例句：

• Several schools face eventual closure.几所学校面临最终关闭。
• Both parties expressed optimism about an eventual solution.双方对问题的最终解决都表示乐观。

6 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

7 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

8 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

9 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

10 anchovies   

n. 鯷鱼，凤尾鱼

参考例句：

• a pizza topped with cheese and anchovies 奶酪鳀鱼比萨饼
• Pesto, mozzarella, parma ham, sun dried tomatoes, egg, anchovies. 核桃香蒜，马苏里拉，巴马火腿，干番茄，鸡蛋，咸鱼。

11 sardines   

n. 沙丁鱼

参考例句：

• The young of some kinds of herring are canned as sardines. 有些种类的鲱鱼幼鱼可制成罐头。
• Sardines can be eaten fresh but are often preserved in tins. 沙丁鱼可以吃新鲜的，但常常是装听的。

12 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

13 forage   

n.(牛马的)饲料，粮草；v.搜寻，翻寻

参考例句：

• They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
• Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。

14 alder   

n.赤杨树

参考例句：

• He gave john some alder bark.他给了约翰一些桤木树皮。
• Several coppice plantations have been seeded with poplar,willow,and alder.好几个灌木林场都种上了白杨、柳树和赤杨。

15 coordinator   

n.协调人

参考例句：

• The UN Office for the Coordination of Humanitarian Affairs, headed by the Emergency Relief Coordinator, coordinates all UN emergency relief. 联合国人道主义事务协调厅在紧急救济协调员领导下，负责协调联合国的所有紧急救济工作。
• How am I supposed to find the client-relations coordinator? 我怎么才能找到客户关系协调员的办公室？

16 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

17 wasteful   

adj.（造成）浪费的，挥霍的

参考例句：

• It is a shame to be so wasteful.这样浪费太可惜了。
• Duties have been reassigned to avoid wasteful duplication of work.为避免重复劳动浪费资源，任务已经重新分派。

18 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

19 conducive   

adj.有益的，有助的

参考例句：

• This is a more conducive atmosphere for studying.这样的氛围更有利于学习。
• Exercise is conducive to good health.体育锻炼有助于增强体质。