Invasive Fish Found in Lower Colorado River
2022-07-09
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1Biologists in the American West are worried about an invasive kind of fish recently found in part of the Colorado River.
2Biologists have been working there to protect native fish which are threatened by the appearance of the smallmouth bass.
3National Park Service fisheries biologist Jeff Arnold found three young smallmouth bass in the lower Colorado River recently.
4The park service confirmed that the fish had been found and were likely reproducing in the Colorado River below the Glen Canyon Dam in the Southwestern state of Arizona.
5The Colorado River is a major river of North America. It travels through parts of seven western U.S. states.
6Construction of the Glen Canyon Dam formed Lake Powell.
7Smallmouth bass are a popular sport fish.
8But they feed on another kind of fish called the humpback chub.
9The humpback chub is an ancient fish that is native to the river but is threatened.
10Biologists like Arnold have been working to help the threatened fish recover.
11Predators like the smallmouth bass have caused problems for the upper river's environment.
12But they were held back for years in Lake Powell by the Glen Canyon Dam.
13However, with water levels dropping, the invasive fish have gotten past the dam and closer to where the chub remain.
14Brian Healy has worked with the humpback chub for more than 10 years.
15He established the Native Fish Ecology and Conservation Program.
16Healy said, "It's pretty devastating 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."
17As lake levels drop, non-native fish that live in warm surface waters in Lake Powell are getting closer to the dam and its penstocks.
18Penstocks are underground steel tubes that carry water to machines that produce electricity from the water current.
19The water is then released on the other side of the dam.
20If predator fish continue to flow through the penstocks and populate the river below the dam, they could harm native fish.
21That could undo years of work restoring the river's environment.
22The chub almost disappeared years ago.
23But the fish have come back with help from fish biologists and scientists and engineers.
24Agencies spend millions of dollars each year to keep invasive species under control in the upper part of the river.
25The Endangered Species Act is a law that requires government agencies to act in ways that will not harm threatened animals.
26That includes structures like the Glen Canyon Dam.
27Federal, state, and other government leaders are expected to release a plan in August containing ideas for policymakers.
28Their aim is to control smallmouth bass and other predatory fish below the dam.
29The National Park Service, U.S. Geological Survey, and Arizona Game and Fish Department are moving quickly to try and contain the problem.
30During an emergency meeting, they decided to increase efforts to follow fish populations and block off the part of the river where the smallmouth bass were found.
31Arnold said the nets being used cannot keep out smaller fish.
32But he noted it is the best his group can do with available resources.
33Experts say leaving more water in Lake Powell would be the best answer.
34But that is difficult under current dry conditions.
35In 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.
36It is unclear where that water will be stored.
37But Healy hopes Lake Powell is being considered.
38I'm Gregory Stachel.
1Biologists in the American West are worried about an invasive kind of fish recently found in part of the Colorado River. 2Biologists have been working there to protect native fish which are threatened by the appearance of the smallmouth bass. 3National 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 Canyon Dam in the Southwestern state of Arizona. 4The 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. 5Smallmouth 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. 6Predators 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. 7However, with water levels dropping, the invasive fish have gotten past the dam and closer to where the chub remain. 8Brian Healy has worked with the humpback chub for more than 10 years. He established the Native Fish Ecology and Conservation Program. 9Healy said, "It's pretty devastating 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." 10As 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. 11If predator fish continue to flow through the penstocks and populate the river below the dam, they could harm native fish. That could undo years of work restoring the river's environment. 12The 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. 13The 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. 14Federal, 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. 15The 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 decided to increase efforts to follow fish populations and block off the part of the river where the smallmouth bass were found. 16Arnold said the nets being used cannot keep out smaller fish. But he noted it is the best his group can do with available resources. 17Experts say leaving more water in Lake Powell would be the best answer. But that is difficult under current dry conditions. 18In 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. 19I'm Gregory Stachel. 20Brittany Peterson reported this story for The Associated Press. Gregory Stachel adapted it for VOA Learning English. 21___________________________________________________________________ 22Words in This Story 23predator - n. an animal that lives by killing and eating other animals 24devastating - adj. causing extreme emotional pain 25species - n. a group of animals or plants that are similar and can produce young animals or plants 26translocate - v. to cause something to be moved from one place or position to another 27net - 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 28___________________________________________________________________ 29What do you think of invasive species? 30We want to hear from you. We have a new comment system. Here is how it works: 31Each time you return to comment on the Learning English site, you can use your account and see your comments and replies to them. Our comment policy is here.