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<br />1 <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />-.I <br /> <br />Introduction <br /> <br />This plan represents a revised and updated approach to the stocking needs for Colorado <br />River endangered fishes presented in Nesler (1998). Since the completion of the previous plan, . <br />considerable effort has been expended in determining quantified recovery goals for each of the <br />four federally listed fish species (Nesler 2000, USFWS 2001a,b,c,d in draft). These goals include <br />criteria for minimum population abundance. At Biology Committee meetings for both the San <br />Juan River and Upper Colorado River Endangered Fish Recovery Programs, the direction was <br />agreed upon to revise stocking plans to be consistent with population abundance criteria developed <br />within the draft recovery plans for each fish species. This revised plan incorporates those criteria <br />as the target stocking objectives for each species' population. <br /> <br />The propagation and stocking of the Colorado River endangered fishes is recognized as <br />one of five primary approaches to attaining the recovery goals for the four listed species-razorback <br />sucker, Colorado pikeminnow (formerly squawfish), bonytail, and humpback chub. The direction <br />to perform tasks related to propagation, augmentation, and restoration stocking are clearly <br />identified in the Recovery Implementation Program report (U.S. Fish and Wildlife Service 1987), <br />the recovery action plan (U.S. Fish and Wildlife Service 1998), and the annual propagation <br />operation plan (Czapla 1997). The annual propagation operation plan will need to be revised to <br />reflect the revised fish stocking needs described here. <br /> <br />Three razorback sucker stocks, three Colorado pikeminnow stocks, five humpback chub <br />stocks, and one bony tail stock have been identified (Wydoski 1995, Czapla 1999). Populations <br />of these species in Colorado rivers that contribute to, or are included within the critical habitat <br />range of these presumptive stocks include razorback sucker and Colorado pikellllnnOW populations <br />in the Colorado River from Rifle downstream to the state line, and in the Gunnison River from <br />Delta downstream to its confluence as part of the Upper Colorado River stocks for both species. <br />Colorado pikeminnow populations in the Yampa and White rivers contribute to the Yampa and <br />Green River-Desolation/Gray Canyon stocks. Presumptive stocks of humpback chub in Colorado <br />include the populations in the Yampa River and Colorado River at Black Rocks Canyon. Bonytail <br />populations formerly occurred in Colorado, based on captures and identifications of this species <br />in the Yampa, Colorado, and Dolores rivers in historic and anecdotal accounts (Kaeding et al. <br />1986, Tyus and Karp 1989, Quartarone 1993), but are now extirpated. This species is now <br />represented by only one captive stock at Dexter National Fish Hatchery in New Mexico. Relict <br />wild stocks exist in Lake Havasu and Lake Mohave in the Lower Colorado River Basin, but are <br />comprised of very old, senescent adults (USFWS 1990a). <br /> <br />This stocking plan provides the rationale for conducting restoration stocking for the four <br />endangered fish species in select rivers of western Colorado within the Upper Colorado River <br />Basin, and includes priorities among species and river reaches, genetics risk assessment, and <br />criteria for contribution to recovery success as well as expectations and limitations. <br /> <br />1 <br />