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• FWS/GJ-6-CO-92-F-007 Page 2 <br />the likelihood of jeopardy. These Conservation Measures should be included as <br />stipulations or conditions of the OSM permit. <br />PROJECT DESCRIPTION <br />Salt Creek Mining Company will construct a road from the McClave Canyon Mine <br />to the Munger Canyon Mine in Township 7S, Range 102W, Garfield County, <br />Colorado. Construction of the road and continuing operation of the mine will <br />require an additional 3.5 acre-foot depletion of water from the Colorado River <br />basin. <br />BASIS FOR OPINION <br />This Biological Opinion addresses the average annual depletion of <br />approximately 3.5 acre-feet of water from the upper Colorado River. <br />Water depletions in the Upper Colorado River Basin have been recognized as a <br />major source of impact to endangered fish species. Continued water withdrawal <br />has restricted the ability of the Colorado River system to produce flow <br />conditions required by various life stages of the fishes. Impoundments and <br />diversions have reduced peak discharges by 50 percent since 1942 while, <br />increasing base flows by 21 percent in some reaches. These depletions along <br />with a number of other factors have resulted in such drastic reductions in the <br />• populations of Colorado squawfish, humpback chub, bonytail chub and razorback <br />sucker that the Service has listed these species as endangered and has <br />implemented programs to prevent them from becoming extinct. <br />Colorado Sauawfish <br />The Colorado squawfish evolved as the main predator in the Colorado River <br />system. The diet of Colorado squawfish longer than three or four inches <br />consists almost entirely of other fishes (Yanicek and Kramer 1969). The <br />Colorado squawfish is the largest cyprinid fish (minnow family) native to <br />North America and, during pre-development times, may have grown as large as <br />six feet in length and weighed nearly 100 pounds (Behnke and Benson 1983). <br />These large fish may have been 25-50 years of age. <br />Based on early fish collection records, archaeological finds and other <br />observations, the Colorado squawfish was once found throughout warm water <br />reaches of the entire Colorado River Basin, including reaches of the upper <br />Colorado River and its major tributaries, the Green River and its major <br />tributaries, and the Gila River system in Arizona (Seethaler 1978). Colorado <br />squawfish were apparently never found in colder, headwater areas. Seethaler <br />(1918) indicates that the species was abundant in suitable habitat throughout <br />the entire Colorado River basin prior to the 1850's. Historically, Colorado <br />squawfish have been collected in the upper Colorado River as far upstream as <br />Parachute Creek, Colorado (Kidd 1977). <br />• A marked decline in Colorado squawfish populations can be closely correlated <br />with the construction of dams and reservoirs during the 1960's, the <br />introduction of nonnative fishes, and the removal of water from the Colorado <br />