Endangered Fish Successfully Translocated

On June 15th, the National Park Service, in conjunction with the Bureau of Reclamation, the Grand Canyon Wildlands Council, the Arizona Game and Fish Department, and the U.S. Fish and Wildlife Service, translocated 300 juvenile humpback chub to Shinumo Creek in Grand Canyon National Park in an effort to establish a satellite population of this endangered fish.

The humpback chub is endemic to the Colorado River basin and populations are impacted by a variety of significant human-caused changes to the Colorado River ecosystem in Grand Canyon, including a dam-altered ecosystem, competition with and predation by non-native fish such as rainbow and brown trout, and non-native parasites such as the Asian tapeworm. Establishing a satellite population in another suitable Grand Canyon tributary is one of the strategies in the species conservation plan.

Shinumo Creek was selected as the site for a humpback chub translocation experiment because it appears to have suitable habitat for humpback chub based on water quality, water temperature, and available food base. It also has a barrier falls just above its confluence with the Colorado River which prevents non-native predatory fish found in the main stem river from moving into the creek.

The juvenile humpback chub released in Shinumo Creek were captured in 2008 near the mouth of the Little Colorado River. The fish were treated for parasites and then kept overwinter at Fish and Wildlife’s Dexter National Fish Hatchery and Technology Center in New Mexico. Prior to releasing the humpback chub in Shinumo Creek, biologists removed approximately 800 non-native rainbow trout to reduce trout predation risk and food competition with trout.

The young humpback chub were actively feeding and behaving normally a few minutes after they were released. Observations made on the humpback chub in early July showed that most of the translocated fish had remained in Shinumo Creek. While the long-term results of this translocation experiment will only be known after several years of monitoring, these preliminary data are encouraging. Further monitoring and additional translocations of young humpback chub to Shinumo Creek are planned for 2010 and 2011.

For further information on the humpback chub translocation experiment, see http://www.nps.gov/grca/naturescience/shinumotransloc.htm