Recovery of upper Colorado River basin fish: Improving habitat

Recovery of upper Colorado River basin fish (Continued)

Improving the river habitat

One strategy being used to improve river habitat is to make river-side flood plain property accessible to endangered fish. In some cases, this involves breaking down or removing dikes along the river to allow the fish to swim into the wetland. In situations where no dikes exist, the approach may be to protect the property from development, ensuring it will continue to be available to the fish.

River habitat also is being improved by building fish passageways and ladders, such as the one shown at left, around dams and other instream barriers, enabling endangered fish to migrate upstream and down.

Accomplishments

A 350-foot fish ladder (shown above at left) has been built at Redlands Diversion Dam, giving endangered and native fish access to 57 miles of historical habitat that had been off-limits for nearly a century. (The ladder is on the Gunnison River two miles upstream of the Colorado River confluence.)

As of 2000, 51 endangered Colorado pikeminnow and more than 35,000 other native fish have successfully used the fish ladder. (The first Colorado pikeminnow to have swum up the ladder is shown on the left.)

A fish passage structure was constructed at the Grand Valley Irrigation Company Diversion Dam on the Colorado River in January 1998. Ten adult Colorado pikeminnow were captured above the GVIC dam between August 19 and September 24, 1998. Providing fish passage at this structure, Price-Stubb, and the Grand Valley Project Diversion Dam will restore 55 miles of historically-occupied habitat for endangered fishes.

Razorback suckers 3 to 5 inches in length were stocked into 3 floodplain wetlands in April 1999. In the presence of nonnative fishes, the razorbacks grew to 14 inches in length. Of the 5,955 razorbacks that were stocked, 1,100 were recaptured. The razorbacks survived in the wetlands over the winter of 1999-2000. In the spring of 2000, ~30 razorbacks were captured trying to leave the wetlands to get into the river; they were subsequently pit-tagged and released into the river. Also during spring runoff 2000, one of the razorbacks that had been stocked into the wetlands was captured at the spawning bar.

Floodplain/wetland habitat has been improved to benefit endangered fish at five Bureau of Land Management sites on the Green River and three sites at the Ouray National Wildlife Refuge near Vernal, Utah, as well as two sites on the Colorado River near Grand Junction.

The Recovery Program has acquired easements on eleven properties along the Green and Colorado rivers for a total of 630 acres of protected habitat.

Recovery Program funds have been used to purchase a 153-acre parcel of land on the Colorado River near Grand Junction, Colo. The property (shown at left) is considered extremely valuable for endangered fish, providing a diverse array of habitat types including riffles, backwaters, pools and side channels.

Researchers have made a 132-acre wetland on the Ouray National Wildlife Refuge in Utah available to endangered fish. The wetland is downstream of the primary known spawning area for razorback suckers in the upper Colorado River basin. Inlet and outlet mechanisms have been installed to control water levels and prevent large non-native fish from entering. Biologists have found young razorback suckers in the wetland, proving that this type of habitat can help the fish survive beyond the critical stage in the wild.

(Go to next page)

Endangered Colorado River basin fish	Historical perspective on these fish	Why these fish are endangered	Upper Colorado River Recovery Program	Improving habitat for the fish
Conducting research	Protecting stream flows	Managing non-native fish	Hatcheries and stocking	Back to Home Page