It was a time that Jeff Arnold had been anticipating. He was pulling in a net in a shallow backwater of the Colorado River when he spotted three fish that didn't belong there. He told his colleague to give him a call when he got the message.
The park service confirmed that smallmouth bass had been found and were likely reproducing in the Colorado River below Glen Canyon Dam.
Smallmouth bass are a popular sport fish, but they also feast on an ancient, threatened fish that is native to the river, and that biologists like Arnold have been working hard to recover. The predators wreaked havoc in the upper river, but were held at bay in Lake Powell, until now. These introduced fish are able to get past the dam because of the recent decline in the lake.
Brian has been working with the humpback chub for more than a decade and founded the Native Fish Ecology andConservation Program.
It is very sad to see all the hard work and effort you have put into removing other non-native species and translocating populations around to protect the fish and to see that effort overturned very quickly.
Non-native fish that live in the warm surface waters of Lake Powell are moving closer to the dam and its penstocks, which generate hydroelectric power.
If bass and other predator fish continue to get sucked into the penstocks, survive and reproduce below the dam, they will have an open lane to attack.
The chub came back in small numbers thanks to fish biologists and other scientists. Agencies spend a lot of money to keep people out of the upper part of the river.
Government agencies are required to operate in ways that don't endanger the continued existence of listed animals under the act. Infrastructure is included.
Agencies had been prepared for this moment before the discovery of smallmouth bass. A team of researchers at Utah State University were enlisted by the U.S. Bureau of Reclamation to map the nonnative fish in Lake Powell.
The low water poses a serious threat to native fish. Federal, state and tribal leaders are expected to release a draft plan in August containing solutions for policymakers who want to delay, slow and respond to the threat of smallmouth bass and other predator below the dam.
Many of the solutions need to change infrastructure.
The National Park Service, U.S. Geological Survey and Arizona Game and Fish Department are trying to contain the problem. They decided during an emergency meeting to block off the entire backwater where the smallmouth bass were found so they couldn't swim out into the river.
The only block nets we have are large mesh, so it won't stop the smaller fish from going through, but it will keep the adults from going back out.
It's difficult to release cool water through the dam in a river under so much stress, but experts say leaving more water in Lake Powell is the best way to do it.
The Department of the Interior notified the seven western states that depend on Colorado River water that they must come up with a way to conserve up to 4 million acre-feet of water in three years. It is not clear where that supply would be stored.
We need to think about how water is stored if we want to protect some of the values of the Grand Canyon National Park. The issue needs to be discussed.
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