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Fewer squawfish are found in the Colorado River. However, occurrence of adult and larval fish has been documented annually since at least 1979 (Valdez et al. 1982b). Recovery of the species in the Colorado subbasin requires the protection of the Colorado River. If stocking proves to be a successful technique, then augmentation of existing populations in the Colorado River may be necessary to provide sufficient numbers of fish for su~:cessful reproduction and effective management. ' Recent studies indicate that the San Juan River contains a small, reproducing population of Colorado squawfish. This river will be especially important if recovery efforts fail on the Colorado or portions of the Green Rivers. Augmentation of existing populations of Colorado squawfish in the San Juan River also may be necessary to provide sufficient numbers of fish for successful reproduction and effective management. Stocking of fish in the San Juan subbasin or in the Green/Upper Colorado subbasin should only be done after the genetics are documented (to determine if a number of genetically separate populations are present) and if it is determined that the current population is not viable. If there are genetically separable populations, then broodstock should be taken from the resident population and young reared for eventual reintroduction into the ' resident reach. However, such stocking should occur only in accordance with an integrated management and restoration plan. The Lower Basin no longer has naturally occurring Colorado squawfish. Much of ' the habitat in the Lower Basin has been sever~:ly altered and contains relatively large populations of introduced fishes. Of the remaining habitat in the Lower Basin, the upper Verde and upper Salt Rivers are most pristine, ' and thus offer the best opportunities for reestablishment of Colorado squawfish. Colorado squawfish in those rivers have been designated nonessential experimental populations (U.S. Fish and Wildlife Service 1985). In addition, there is an active proposal by the Service to reintroduce ' Colorado squawfish into the mainstem Colorado River between Parker and Imperial dams and designate them a nonessential experimental population. The nonessential experimental designation allows stocked fish to be treated as threatened species. For purposes of Section 7, any experimental population occurring within a National Park or National Wildlife Refuge is treated as threatened. Outside of National Parks or National Wildlife Refuges, any , experimental population is treated as a proposed species for Section 7 purposes. Lower Basin rivers also provide opportunities to conduct valuable research and ' experimentation that may not be feasible or desirable in the Upper Basin. Ongoing stocking and monitoring efforts by Lower Basin researchers could lead to a better understanding of the habitat requirements, homing behavior, and ' factors limiting Colorado squawfish survival. These activities will add to our understanding of squawfish biology and support recovery efforts throughout the Colorado River basin. , 18 '