VOA新闻杂志2022--科罗拉多河下游发现入侵鱼类

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Invasive Fish Found in Lower Colorado River

Biologists in the American West are worried about an invasive kind of fish recently found in part of the Colorado River.

Biologists have been working there to protect native fish which are threatened by the appearance of the smallmouth bass¹.

National Park Service fisheries biologist Jeff Arnold found three young smallmouth bass in the lower Colorado River recently. The park service confirmed that the fish had been found and were likely reproducing in the Colorado River below the Glen Canyon² Dam in the Southwestern state of Arizona.

The Colorado River is a major river of North America. It travels through parts of seven western U.S. states. Construction of the Glen Canyon Dam formed Lake Powell.

Smallmouth bass are a popular sport fish. But they feed on another kind of fish called the humpback chub. The humpback chub is an ancient fish that is native to the river but is threatened. Biologists like Arnold have been working to help the threatened fish recover.

Predators⁴ like the smallmouth bass have caused problems for the upper river's environment. But they were held back for years in Lake Powell by the Glen Canyon Dam.

However, with water levels dropping, the invasive fish have gotten past the dam and closer to where the chub remain.

Brian Healy has worked with the humpback chub for more than 10 years. He established the Native Fish Ecology and Conservation Program.

Healy said, "It's pretty devastating⁵ to see all the hard work and effort you've put into removing other invasive species and translocating populations around to protect the fish and to see all that effort overturned really quickly."

As lake levels drop, non-native fish that live in warm surface waters in Lake Powell are getting closer to the dam and its penstocks. Penstocks are underground steel tubes that carry water to machines that produce electricity from the water current. The water is then released on the other side of the dam.

If predator³ fish continue to flow through the penstocks and populate the river below the dam, they could harm native fish. That could undo⁶ years of work restoring the river's environment.

The chub almost disappeared years ago. But the fish have come back with help from fish biologists and scientists and engineers. Agencies spend millions of dollars each year to keep invasive species under control in the upper part of the river.

The Endangered Species Act is a law that requires government agencies to act in ways that will not harm threatened animals. That includes structures like the Glen Canyon Dam.

Federal, state, and other government leaders are expected to release a plan in August containing ideas for policymakers. Their aim is to control smallmouth bass and other predatory fish below the dam.

The National Park Service, U.S. Geological Survey, and Arizona Game and Fish Department are moving quickly to try and contain the problem. During an emergency meeting, they decided⁷ to increase efforts to follow fish populations and block off the part of the river where the smallmouth bass were found.

Arnold said the nets being used cannot keep out smaller fish. But he noted⁸ it is the best his group can do with available resources.

Experts say leaving more water in Lake Powell would be the best answer. But that is difficult under current dry conditions.

In June, the Department of the Interior told the seven states that depend on the Colorado River to save nearly 5 billion cubic meters of water. It is unclear where that water will be stored. But Healy hopes Lake Powell is being considered.

Words in This Story

predator – n. an animal that lives by killing⁹ and eating other animals

devastating – adj. causing extreme emotional pain

species – n. a group of animals or plants that are similar and can produce young animals or plants

translocate – v. to cause something to be moved from one place or position to another

net – n. a device that is used for catching or holding things or for keeping things out of a space and that is made of pieces of string, rope, or wire woven together with spaces in between

1 bass   

n.男低音(歌手)；低音乐器；低音大提琴

参考例句：

• He answered my question in a surprisingly deep bass.他用一种低得出奇的声音回答我的问题。
• The bass was to give a concert in the park.那位男低音歌唱家将在公园中举行音乐会。

2 canyon   

n.峡谷，溪谷

参考例句：

• The Grand Canyon in the USA is 1900 metres deep.美国的大峡谷1900米深。
• The canyon is famous for producing echoes.这个峡谷以回声而闻名。

3 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。

4 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》

5 devastating   

adj.毁灭性的，令人震惊的，强有力的

参考例句：

• It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
• Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。

6 undo   

vt.解开，松开；取消，撤销

参考例句：

• His pride will undo him some day.他的傲慢总有一天会毁了他。
• I managed secretly to undo a corner of the parcel.我悄悄地设法解开了包裹的一角。

7 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

8 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

9 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。