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razorback suckers. Seventy-six pools larger than 80 square feet were documented in Anderson's fall survey. Twenty-five potential Colorado squawfish spawning sites, comprised of sediment-free cobble bars adjacent to pools greater than 160 square feet, were reported by Anderson. The combination of cobble bars adjacent to pools are required as spawning sites for Colorado squawfish (Tyus, 1986, 1990, 1991). Although water temperatures in the Colorado River reach above the diversion dams is cooler than downstream, Colorado squawfish will spawn at these temperatures. Recently hatched fish drift and grow in downstream reaches from spawning sites where temperatures are more suitable for their growth. Therefore, the overall area upstream from the diversion dams contains suitable habitat for both endangered fish species. The 54-mile reach of the Colorado River upstream from Palisade contains lower selenium levels than downstream reaches. There is some concern that high selenium concentrations may adversely impact the reproductive success of adult endangered fishes and could be toxic to young fish resulting in high mortality to the point that no young fish survive. Related Projects Many existing water projects and related activities are in place on the Colorado River, and new developments are being considered. Transmountain diversions, irrigation projects, direct irrigation diversions, and a growing human population occur upstream. In addition to provision of fish passage, the Recovery Program contains other related activities. One of the Recovery Program endeavors includes captive propagation of endangered fish to be used for stocking river reaches of historic habitat that have been designated as critical for recovery of the endangered fishes. The razorback sucker, which has exhibited a dramatic decline in the Upper Colorado River between the 1970's and 1980's (Burdick 1992), could benefit from stocking. Burdick reported that a record catch of 206 razorback suckers during various studies (primarily in the Grand Valley) occurred in 1975, but no fish were captured between 1989 and 1992. Since 1992, only a few individual razorback suckers have been collected from the Upper Colorado River by investigators who are conducting studies under the Recovery Program. Brood stocks for use in captive propagation are being developed following "Genetics Management Guidelines" that were developed by the Recovery Program using wild adult endangered fish. At the present time, a broodstock for razorback suckers is being developed for stocking historic reaches in the Colorado and Gunnison Rivers that are either presently unoccupied or that contain few endangered fish. Stocking plans have been developed for restoration and augmentation stocking the razorbacks in both rivers. To date, experimental stocking of razorback suckers has been made in the Gunnison to evaluate various factors such as the size of fish that would provide the best survival after stocking. As captive-reared razorback suckers are available, stocking of the Colorado River upstream from the diversion dams is proposed in the stocking plans. Development of a broodstock for Colorado squawfish has been initiated also. Anderson (1997) has made recommendations for stocking of these fish in the reach