科学家们帮助昆虫的同时也是帮助科罗拉多河鱼

Scientists Help Insects to Help Colorado River Fish

Fish need insects for food. So, healthy rivers have healthy insect populations. However, in the United States, part of the Colorado River has an insect shortage² that has left many fish without food.

Researchers are hoping a month-long water-flow experiment will improve the situation. The U.S. Geological³ Survey project involves the release of low, continuous water flow from Glen Canyon⁴ Dam. This will give insect eggs, which they lay just below the water's surface, a better chance to survive.

The Colorado runs 2,330 kilometers from the Rocky Mountains of Colorado to Lake Mead⁵, on the border between the states of Arizona and Nevada. The Glen Canyon Dam is near the border between the states of Utah and Arizona.

Lacking diversity

"For whatever reason, downstream of Glen Canyon Dam really lacks diversity," said Scott VanderKooi, who runs the U.S. Geological Survey's Grand Canyon Monitoring and Research Center in Flagstaff.

Scientists expect a 26 percent increase in insects, such as black flies and midges, by next summer. Scientists say that when insect populations grow, so do the populations of other animals such as fish, bats, birds and other insect eaters.

Insects attach their eggs to hard surfaces, such as rocks or wood, on riversides. As water from dams rises and falls the eggs can lose their cover and dry out.

If they remain above the water line for even an hour, they die, said Jeff Muehlbauer, a research scientist with the Geological Survey.

The water flows are part of a larger plan approved in late 2016 for operations at Glen Canyon Dam to improve fish life. The dam holds back Lake Powell.

John Hamill, a volunteer with the organization Trout⁶ Unlimited⁷, says the experiments will help explain the current situation of all the different river resources. Then, officials can make changes based on how the river ecosystem⁸ is changing.

Studying flies

People often fish along a 25 kilometer run of the Colorado River below the dam. However, a lack of insects means some of the fish caught are smaller than normal. Hamill says this has caused a lot of people to fish in different places.

"It hasn't been a very dependable fishery," Hamill said.

Ted¹ Kennedy started working at the Geological Survey in 2002. He said at that time scientists had noted⁹ the low number of flies and other insects throughout the Grand Canyon.

Kennedy began studying the lives of insects before they hatch¹⁰. He asked river guides and students for help studying the adult insect life as well.

Since 2012, the volunteers have set out plastic containers for an hour each night. A special light is attached that leads the insects into the containers.

The evidence from the containers showed researchers that fish in the area have a weak food source. This problem leads to fish that are longer, thinner, do not swim well, and do not have the energy to reproduce¹¹ or fight.

The U.S. Geological Survey scientist Ted Kennedy said, "When things are bad for midges, there's not much else to take its place."

I’m Phil Dierking.

Words in This Story

diversity – n. the quality or state of having many different forms, types, ideas, etc.?

downstream – adv. in the direction in which a stream, river, etc., flows?

hatch – v. an opening in the deck of a ship or in the floor, wall, or roof of a building

1 ted   

vt.翻晒，撒，撒开

参考例句：

• The invaders gut ted the village.侵略者把村中财物洗劫一空。
• She often teds the corn when it's sunny.天好的时候她就翻晒玉米。

2 shortage   

n.缺少，缺乏，不足

参考例句：

• The city is suffering a desperate shortage of water.这个城市严重缺水。
• The heart of the problem is a shortage of funds.问题的关键是缺乏经费。

3 geological   

adj.地质（学）的

参考例句：

• aeons of geological history 数以亿万年计的地质史
• The workers skirted the edge of the cliff on a geological survey. 工人们沿着崖壁作了一次地质勘察。 来自《简明英汉词典》

4 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。

5 mead   

n.蜂蜜酒

参考例句：

• He gave me a cup of mead.他给我倒了杯蜂蜜酒。
• He drank some mead at supper.晚饭时他喝了一些蜂蜜酒。

6 trout   

n.鳟鱼；鲑鱼(属)

参考例句：

• Thousands of young salmon and trout have been killed by the pollution.成千上万的鲑鱼和鳟鱼的鱼苗因污染而死亡。
• We hooked a trout and had it for breakfast.我们钓了一条鳟鱼，早饭时吃了。

7 unlimited   

adj.无限的，不受控制的，无条件的

参考例句：

• They flew over the unlimited reaches of the Arctic.他们飞过了茫茫无边的北极上空。
• There is no safety in unlimited technological hubris.在技术方面自以为是会很危险。

8 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。

9 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。

10 hatch   

n.孵化，舱口；vt.孵，孵出，策划；vi. 孵化

参考例句：

• No one knows how the new plan will hatch out.谁也不知道这新方案将怎样制订出来。
• The bird mistook the pebble for egg and tried to hatch it.这只鸟错把卵石当蛋，想去孵它。

11 reproduce   

v.生育，繁殖，复制，重做

参考例句：

• The machine can reproduce a key in two minutes.这机器能在两分钟内复制一把钥匙。
• The picture will reproduce well.这照片会印得很清楚。