Laserfiche WebLink
The mainstream Colorado River above Palisades, Colorado potentially offers habitat for <br />some endangered fishes and has been designated critical habitat for the Colorado <br />pikeminnow as far upstream as Rifle, Colorado. Habitat suitability for endangered <br />fishes is likely due to their prior historical distributions and an abundance of other native <br />fishes. Potential use of that habitat has not been realized due to barriers {Price-Stubb <br />and Government High(ine dams) that preclude upstream movement of fishes. Re- <br />establishing access to this area for the Colorado pikeminnow should benefit recovery of <br />the population now centered in the 15-Mile Reach. Reintroduction of razorback suckers <br />and humpback chub also may be desirable. <br />The Gunnison River provides significant indirect contributions to the Colorado River <br />mainstream, despite the presence of major water development projects. Direct <br />contributions are more limited, primarily due to barriers to fsh movement. A few <br />Colorado pikeminnow live and reproduce in the lower Gunnison River, and a stocking <br />program for razorback suckers is now underway. The lower Gunnison River has been <br />designated as critical habitat for both of these species. Although a fish passage <br />structure now makes it possible for Colorado pikeminnow and other native fishes to <br />traverse the Redlands diversion, more fish would probably move upstream if the barrier <br />was removed. Passage through the Hartland Dam also deserves more consideration. <br />Little is known about historical use of the Dolores River by endangered fishes. For <br />many years, poor water quality presumably prevented fish from using the lower part of <br />the river. Water quality has improved in recent years and there may now be ~ greater <br />potential for use of this river for endangered fish recovery. <br />The Dirty Devil and Escalante rivers now empty into Lake Powell and have little indirect <br />affect on mainstream fish habitat. In addition, it seems unlikely that either stream <br />provided a great amount of historic habitat for the endangered fishes, except perhaps at <br />the river mouths. In the present setting, however, the arms of Lake Powell that receive <br />these two streams seem to be attractive to Colorado pikeminnow and razorback <br />suckers that presumably reside in the lake. It is not known why the fish congregate in <br />these arms, but the topic merits further study if Lake Powell is targeted for more <br />recovery effort. <br />The four "Big River" endangered fishes of the upper Colorado River basin are most <br />abundant in mainstream habitat, and past recovery efforts have concentrated on the <br />larger rivers. As more is understood about the recovery needs of the endangered <br />fishes, it is becoming obvious that recovery can benefit by better integration of <br />tributaries into the ongoing recovery effort. The Recovery Program is evolving an <br />ecosystem view, which also should include priority efforts to maintain other native fishes <br />of the Big River fish community in addition to listed species. However, the process is <br />slow and far from complete. Greater involvement of the tributaries could include a <br />review of the appropriateness of critical habitat designations. This review would entail <br />an evaluation of the importance of habitat for life history stages, presumably from <br />patterns of fish use. A unified view of habitat use needs to be developed by <br />x <br />