http://www.newsweek.com/invasive-fish-may-swarm-lake-powell-water-levels-decline-1785387

An invasive fish species could begin swarming more areas of the Colorado River, officials have warned.

In a report released in February by the Bureau of Reclamation, concerns are raised that smallmouth bass—an invasive species established in Colorado River reservoir Lake Powell—could escape into other reaches of the river, below the dam.