In 2003, scientists targeted invasive fish in the Grand Canyon. By 2006, Rainbow Trout fell from 90% to less than 10% of the catch

For four years, scientists carried out an ambitious fish-removal experiment in the Grand Canyon in an effort to protect one of the Colorado River’s most important native species.

Between 2003 and 2006, researchers mechanically removed non-native fish from a section of the Colorado River to reduce predation and competition affecting the federally protected humpback chub.