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MAINTAINING RAZORBACK SUCKER IN LAKE MOHAVE tenance effort was through an active stocking and management program. We were confident stocking 25-cm razorback suckers was feasible, but we had to identify where, by whom, and how these fish were going to be raised. No one agency volunteered the funds or facilities to accomplish this task; it became a cooperative effort. We were unable to identify any existing cul- turing facilities that would raise tens of thousands of large razorback suckers, nor did we have the re- sources to build new facilities. As an alternative to conventional culturing, we proposed to develop a low-cost, on-site rearing program as a method of producing 10,000, 25-cm razorback suckers. We thought if this concept worked, it could be used to reintroduce and maintain other Threatened or En- dangered, long-lived fish species in different reser- voir and riverine habitats. The debate over the method of producing genet- ically acceptable razorback suckers has been an evolutionary process. Mitochondrial DNA diversity in the Lake Mohave population is high compared with other relict populations located farther up- stream (Dowling and Minckley 1993). The reservoir population is composed of direct descendants of a very large, diverse population that inhabited the river prior to impoundment. Methods being used to produce 25-cm razorback suckers were reviewed in autumn 1993 (Dowling and Minckley 1993). Natu- ral spawning (stocking reservoir adults in backwa- ters) was successful only 1 of 2 years. The progeny produced by these fish exhibited the greatest growth but resulted in only 296 juveniles for the 2-year effort. Genetic analysis suggested the majority of these fish came from very few females. We also suspected the use of early spawners may not have adequately represented the total spawning effort. Fertilized egg experiments were unsuccessful, par- tially because of unpredictability of reservoir oper- ations. Light-trapping experiments showed that large numbers of razorback sucker larvae could be harvested (Mueller et al. 1993). Dowling and Minckley (1993) recommended, in order of priority, the following methods for producing razorback suckers for stocking into Lake Mohave: (1) collect naturally produced larvae, (2) artificially collect ga- metes (protocol would be developed), (3) stock backwaters with spawning adults, and (4) use hatch- ery-produced fish. The method of choice, collecting larvae naturally spawned in the reservoir, allows us to produce young adult razorback suckers that rep- resent greater genetic diversity than those produced using other recommended matrix spawning tech- niques or hatchery facilities (Williamson and 133 Wydoski 1994; Dowling and Minckley, in press). Rather than manipulate spawning, we are now tak- ing advantage of the product of natural spawning as a means of conserving the population's genetic di- versity. Fish have survived nearly 18 months since their release into Lake Mohave. Return of 15 of 640 stocked fish from an 11,400-ha reservoir was higher than expected and represents the largest number of subadults collected from Lake Mohave, and possi- bly the entire Colorado River, in the last 20 years. We anticipate returns will increase in 1995; a total of 2,880 fish have been released and earlier-stocked females should become sexually active and more susceptible to capture. Active management of relict populations is a crit- ical component of recovery that many feel is being neglected or overlooked. The razorback sucker is following the same path toward extinction as other fish species. For instance, the bonytail, which co- inhabits the Colorado River, was federally listed as Endangered in 1980. A recovery plan was formal- ized in 1984 (revised in 1990) calling for the aug- mentation of wild populations through stocking (Colorado River Fishes Recovery Team 1984). Even though culturing facilities, broodstock, and a recovery plan have been in place for over a decade, managers remain reluctant to stock fish. Bonytail are now considered extirpated from the upper Col- orado River basin, where less than 5 have been captured during the last 10 years (USFWS 1990; R. S. Wydowski, personal communication). Con- cerns have now shifted from recovery to preventing extinction. The "hands off" recovery philosophy for the bonytail and the razorback sucker is failing while unique, irreplaceable biological components are be- ing lost. The necessity for an active and long-term management commitment to maintain these popu- lations was recognized 14 years ago (W. H. Miller 1982), but researchers have not identified any solu- tions. Management should be considered a practical safeguard to conserve remaining populations while recovery programs are further developed, imple- mented, and tested. Reversing environmental deg- radation will take a concerted and long-term com- mitment not obtainable in a 10- or 15-year recovery program. The Lake Mohave program falls short of recovery; however, it does represent a modest step toward conserving an existing population. Similar, proactive management approaches are needed to prevent further population declines and potential extinctions.