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thermal control devices placed in Glen Canyon Dam). Such options as simultaneously running steady flow experiments with removal of predators have not yet been attempted. In short, the efforts to date to improve natural recruitment of humpback chub in Grand Canyon have been minimal, or have only begun, and many of the major options have not yet been attempted. The Recovery Goals for humpback chub call for no significant decline occurring in the number of adult fish within each wild population. In addition, each core minimum viable population (MVP) must be self-sustainable, genetically and demographically viable, and contain adult (>200 mm) estimates whose lower 95% confidence interval exceeds 2,100. The sizes for the MVPs were calculated based upon a Ne of 500 (USFWS 2002a). This number is considered a minimum in terms of viable population standards (Soule 1980, Franklin 1980), and is considered by many to be an inadequate safeguard against extinction (Shaffer 1981, Simberloff 1988, Boyce 1992, Lande 1995, Minckley et al. 2003). Thus, managers for the humpback chub face a difficult situation. There does not appear to be a need to demographically boost populations of humpback chub in order to meet the proposed MVP standards and reach recovery. And undertaking a management action (such as release of captive propagated fish) has the potential to further reduce Ne, or lead to introgression of deleterious alleles; thus further jeopardizing the humpback chub. Yet, waiting to take action until humpback chub fall below an arguably insufficient MVP standard does pose some risk for a loss of opportunity for maintaining full genetic variability. In view of this, the above should not be construed to preclude preliminary efforts toward a captive broodstock. The main benefit of a captive brood stock at this point should not be to significantly contribute toward a demographic boost in the population of humpback chub in the LCR. Rather a primary contribution of a captive broodstock should be to capture and maintain maximum genetic variability. Prior to implementation, the ongoing genetics work on humpback chub should be completed. A formal and comprehensive captive brood stock development plan as well as a reintroduction plan should be completed. The genetic variability of any humpback chub in captivity should be compared to the genetic variability of the wild population at large in the LCR. It would be advisable to complete, and to perform similar genetics work on the 30-mile aggregation of humpback chub in the Colorado River. In other words, to capture and maintain maximum genetic variability in the event of initiating a future captive brood stock program, it is advisable to accelerate and complete as much preliminary genetics work as is needed. How many fish will be needed, what size fish should be collected, when, where, and how? All options for fish collection should be identified in a formal broodstock management plan, and decisions based from that document. There are a number of approaches that could be taken to start a brood stock including streamside spawning (i.e., collection of fertilized eggs), collection of younger fish such as age-O, or collection of spawning sized 17