In 2006, Grand Canyon began a major trout-reduction effort in Bright Angel Creek; after invasive brown and rainbow trout were suppressed, the National Park Service says native fish populations increased by more than 400%

• At least five of the Grand Canyon's eight species of native fish were historically found in Bright Angel Creek.
• However, these species that are uniquely adapted to the characteristics of the Colorado River and its tributaries have suffered serious declines over the years due to human-caused changes to their habitat.
• The creek once supported a large number of native fish, including the endangered humpback chub.