2011-05-12_PERMIT FILE - M2011028 (2)

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• Colorado River from Colorado River bridge at exit 90 north off Interstate 70 (near Palisade, Colorado) downstream to North Wash, including Dirty Devil arm of Lake Powell. • San Juan River from Hogback Diversion downstream to Neskahai Canyon in the San Juan arm of Lake Powell. • Colorado River from confluence of Paria River downstream to Hoover Dam, including Lake Mead. • Colorado River from Hoover Dam downstream to Davis Dam, including Lake Mohave. • Colorado River from Parker Dam downstream to Imperial Dam, including Imperial Reservoir. • Gila River from the Arizona-New Mexico border downstream to Coolidge Dam. • Salt River from U. S. Highway 60/SR 77 bridge downstream to Roosevelt Diversion Dam. • Verde River from U. S. Forest Service boundary (Prescott National Forest) downstream to Horseshoe Dam, including Horseshoe Lake. 3.2.2 Distribution Historic distribution of razorback sucker in the upper basin included the Colorado, Green, and San Juan River drainages (Minckley et al. 1991; Holden 1999; Muth et al. 2000). Evidence suggests that the species was common and possibly locally abundant in the lower reaches of the Green and Colorado rivers and in the lower reaches of some tributaries (Minckley et al. 1991; Muth et al. 2000). This species was reported from the White, Duchesne, Little Snake, Yampa, and Gunnison rivers (Burdick 1995), and, although evidence is sparse and anecdotal, as far up the San Juan River drainage as the Animas River (Jordan 1891; Minckley et al. 1991; FWS 1998). Razorback sucker are currently found in the Green River, upper Colorado River, and San Juan River subbasins; reservoirs of Lakes Mohave, Mead, and Havasu; and in small tributaries of the Gila River (Verde River, Salt River, and Fossil Creek). The fish in all populations are aged and senile adults with little or no reproduction and recruitment, except for the middle Green River and Lake Mead, where small numbers of juveniles and young adults indicate low recruitment levels (Guttermuth et al. 1994; Modde et al. 1996; Holden et al. 1999a, 1999b). Young produced by wild adults in Lake Mohave are captured and raised in protected environments then released back to the reservoir. Hatchery-reared razorback sucker (939 individuals) were introduced into the San Juan River between March 1994 and October 1996 (Ryden 2000b). Fifty-seven of these fish were implanted with radio- transmitters to monitor habitat use and movement. The fish used primarily two river locations associated with backwater habitats (RM 38.6 and RM 77.3), and one location may be associated with spawning (RM 100.2) (Ryden 2000b). During May 1997, two larval razorback sucker were collected downstream of RM 90, representing the first successful reproduction by the species in the San Juan River. Weetninuche Construction Auffic? B-8 P.O. Box AA - T owaoc, CO 8133 4 ra144t gtr 14 - PAGE 14-&0