Fisheries

Native Fish Ecology and Conservation

 

Fish native to Grand Canyon, from left to right: humpback chub, razorback sucker, flannelmouth sucker, bluehead sucker, speckled dace, and the three extirpated species: Colorado pikeminnow, roundtail chub and bonytail.

Illustrations by Joe Tomelleri

 

Grand Canyon National Park’s native fish evolved within its dynamic environment. Brian Healy/NPS

 

The Colorado River, the largest river system in the southwestern United States, runs 278 miles through Grand Canyon National Park. The river 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 load of sand and silt.

As a result, only eight fish species are native to Grand Canyon. Of the eight species, six are endemic, meaning that they are only found in the Colorado River basin.

Many of these Colorado River specialists share distinctive physical characteristics and life-histories: large adult size, a distinctive hump or keel behind the head, spawning migrations cued by spring runoff, and extreme longevity (with lifespans of 40 years or more).

Today, due to changes to the ecosystem, only five of Grand Canyon's native fishes are still found within 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 currently listed as a threatened species after many years classified as endangered. Razorback sucker, an endangered species, are currently rare within the park. Through all of the challenges, including invasive fish, the alteration of their river habitat and blockage of migratory routes by Glen Canyon and Hoover dams, native fishes still dominate most of the river in Grand Canyon, with Grand Canyon National Park hosting the largest remaining population of humpback chub.

 

Spawning flannelmouth suckers, mouth of Havasu Creek. NPS Photo/Amy Martin

 

Grand Canyon National Park, through the Grand Canyon’s Native Fish Ecology and Conservation (NFEC) program, and its cooperators, are engaged in a multi-faceted program to restore native fish communities in Grand Canyon. Grand Canyon’s NFEC activities are guided by its Comprehensive Fisheries Management Plan, completed in 2013 with Glen Canyon National Recreation Area, and with coordination and consultation with biologists from the Arizona Game and Fish Department, U.S. Geological Survey, U.S. Bureau of Reclamation, and the U.S. Fish and Wildlife Service. 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.

The NFEC program’s efforts to conserve the Grand Canyon’s unique native fishes are supported primarily by the U.S. Bureau of Reclamation (Reclamation). Reclamation’s Upper Colorado Region programs and activities include endangered species protection and recovery, water conservation, adaptive management of Glen Canyon Dam operations, water reclamation and reuse, water use efficiency improvements, dam safety, cultural resources, resources management and planning, water quality, assistance to Native American tribes and pueblos, and wetlands enhancement.

 

Fisheries biologists at work monitoring humpback chub in Havasu Creek. (Photo: Amy S. Martin)

The NFEC promotes native fish recovery and conservation in Grand Canyon through population monitoring, applied research, translocations, and suppression of invasive species.

This program includes translocating humpback chub from the Little Colorado River source population to Shinumo, Havasu and Bright Angel creeks, Grand Canyon tributaries that may provide suitable habitat for the species.

 

A biologist releases a humpback chub into Havasu Creek, 2021. NPS Photo/Amy Martin

 

Biologists with the NFEC program are removing invasive trout and other invasive fishes in an effort to minimize threats of predation and restore native fishes and habitat in larger perennial tributaries.

The NPS and its cooperators are also monitoring the current status of endangered razorback sucker in Grand Canyon, and considering potential management actions that may be necessary to conserve the species. Area resource management agencies are also in the initial stages of assessing the feasibility of reestablishing endangered Colorado pikeminnow in Grand Canyon for recovery purposes.

Grand Canyon's native fishes are an integral and unique part of the canyon's natural ecosystems. Robust populations of native fishes are important indicators of an aquatic system's overall health. Restoring native fishes to the extent possible in the Colorado River and its tributaries in Grand Canyon is essential to maintaining and enhancing the ecological integrity of the Colorado River ecosystem.

 

Learn More

 

 

• Review Grand Canyon National Park's Comprehensive Fisheries Management Plan An Environmental Assessment (EA) was released to the public in June 2013, for a 30-day review and comment period. Over fifty comments were received, with most in support of Alternative 2, the preferred alternative. Learn more >>
• Invasive Quagga Mussels Threaten Grand Canyon Water
• Fishing Regulations