The Colorado River running through Grand Canyon once hosted one of the most distinctive fish assemblages in North America. The wild Colorado River presented fish with a challenging and variable aquatic habitat: very large spring floods, near-freezing winter temperatures, warm summer temperatures, and a heavy silt load.
Based on anecdotal reports from early researchers, it is likely that native fish populations in Grand Canyon began to decline as early as the 1890s. Today, only five of Grand Canyon's native fish are still found in the park. The humpback chub, a large and unusual-looking member of the minnow family specifically adapted to the deep swift reaches of the Colorado River, is listed as an endangered species. Razorback suckers, also listed as endangered, are very rare within the park.
Native fish in Grand Canyon face a myriad of threats today, including non-native fish and the alteration of their river habitat by Glen Canyon Dam. National Park Service Management Policies require that native species and natural ecosystems are preserved, and that recovery actions are taken when park resources have been damaged or compromised.
Furthermore, a variety of laws, including the Endangered Species Act, require the protection of threatened and rare species.
Fisheries Management Plan
The National Park Service (NPS) released a Finding of No Significant Impact (FONSI) on December 9, 2013 for the Comprehensive Fisheries Management Plan for the Glen Canyon reach of the Colorado River below Glen Canyon Dam within Glen Canyon National Recreation Area (GLCA), and for all waters within Grand Canyon National Park (GRCA).
Last updated: February 14, 2021