There are efforts under way to restore a stream in Grand Canyon National Park with some endangered humpback chub.

Working with the U.S. Bureau of Reclamation, the Grand Canyon Wildlands Council, the Arizona Game and Fish Department, and the U.S. Fish and Wildlife Service, park crews are planting 300 juvenile humpback chub previously removed from the Little Colorado River to Shinumo Creek located within the Grand Canyon inside the park boundaries.

The goal of this experiment is to gather information about how this endangered species will respond to translocation to a smaller Grand Canyon tributary. Information gathered from this effort will contribute to potential establishment of a satellite population of humpback chub in Grand Canyon and provide an opportunity for rearing humpback chub in a natural environment outside of the Little Colorado River.

The humpback chub (Gila cypha) is an unusual-looking member of the minnow family endemic to the Colorado River Basin. These fish, which can live as long as 30 years and reach lengths of almost 20 inches, are characterized by large fins and a pronounced muscular hump on the back of adults immediately behind their heads. Like the other fish endemic to the Colorado River, humpback chub are adapted to the river’s natural conditions—high turbidity and seasonally variable flows and temperatures.

The humpback chub was first listed as an endangered species in 1967 and today is protected under the Endangered Species Act. The decline in humpback chub populations is due to a variety of significant human-caused changes in the Colorado River Basin. In Grand Canyon, humpback chub face a dam-altered ecosystem, as well as competition with and predation by non-native fish such as rainbow and brown trout, non-native parasites such as the Asian tapeworm, and the possibility of a catastrophic event such as a hazardous materials spill from a bridge that crosses the Little Colorado River.

The largest humpback chub population in Grand Canyon is near the confluence of the Little Colorado and the Colorado rivers. Most humpback chub spawn successfully in the Little Colorado River because the water released from Glen Canyon Dam is too cold for successful reproduction. The conservation of humpback chub is a critical component of Colorado River management in Grand Canyon. One of the options for conserving this species and improving the status of native fish in Grand Canyon National Park is to establish a satellite population in a suitable Grand Canyon tributary.

The successful translocation of humpback chub to above Chute Falls in the Little Colorado River between 2003 and 2005 demonstrated the feasibility of using translocation techniques for humpback chub in Grand Canyon.

Shinumo Creek is a small, clear tributary that joins the Colorado River at approximately River Mile 109. It has dense vegetation along the shoreline and supports an abundance of aquatic and riparian invertebrates.

“Shinumo Creek was selected for the translocation experiment because it appears to have suitable habitat for humpback chub based on water quality, water temperature, and available foodbase," says Martha Hahn, the park's chief of science and resource management. "It also has barrier falls just above its confluence with the Colorado River which will keep non-native predator fish out of Shimumo Creek. Together, these attributes make Shinumo Creek the ideal spot for this experiment and we look forward to seeing how the fish do there after the translocation.”

The humpback chub for the planting were captured in July and October 2008 near the mouth of the Little Colorado River. The 2 – 4 inch juvenile fish were transported out of the canyon by helicopter and then were treated to remove parasites at the Arizona Game and Fish Department’s Bubbling Ponds Fish Hatchery in Page Springs, Arizona.

The fish overwintered at the U.S. Fish and Wildlife Service Dexter National Fish Hatchery and Technology Center, in Dexter, New Mexico, to grow to a size that would allow identification tags to be implanted. The tags, known as PIT (passive integrated transponder) tags, which are small electronic tags that will aid in monitoring after translocation, were implanted within the fish a month before the translocation.

“Monitoring the fish with PIT tags will allow us to scientifically evaluate the success of this experiment," says Ms. Hahn. "PIT tags allow biologists to uniquely identify each fish and we will be able to ascertain which fish stayed in Shimuno Creek or were perhaps washed into the mainstem Colorado River during monsoonal flooding.”

A three-year monitoring program will follow the translocation of humpback chub into Shinumo Creek. Additional translocations to augment the Shinumo Creek population will be considered based upon the analysis of the first year’s findings.