Scientists have expressed particular concerns about one such species, the smallmouth bass, which has made its way downstream since its introduction in 1982 and potentially brought with it a potential threat to native species.

They are especially worried about potential threats to the humpback chub, a species subject to federal protections. 

Native species dominated the Grand Canyon until relatively recently, which is “a really rare and unique thing in the Colorado River system,” Brian Healy, a research biologist at the U.S. Geological Survey, told The Hill.

Now, however, years of warming have helped the chub population recover, “which is good for native species, but it’s also good for a non-native species,” said David Rogowski, a Colorado River research biologist for the Arizona Game and Fish Department.

Read more in a full report from our colleague Sharon Udasin at TheHill.com.

Welcome to The Hill’s Energy & Environment newsletter, we’re Rachel Frazin and Zack Budryk — keeping you up to speed on the policies impacting everything from oil and gas to new supply chains.