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<br />wide recovery teams. Research and management in the river
<br />system as a whole should be reviewed and coordinated by
<br />a single panel, and peer review and publication of results
<br />in refereed journals must receive greater emphasis.
<br />Beyond the need for research is that for rehabilitation
<br />(sensu Regier et al. 1989). A water budget for the system
<br />and consideration of requirements of aquatic organisms in
<br />water management are needed. Remediation to benefit big-
<br />river fishes of the upper basin should include habitat
<br />manipulations and fish passage facilities (Valdez and Wick
<br />1983; Tyus 1984; Tyus et al. 1984; Berry and Pimentel
<br />1985; US Department of the Interior 1986a). The impor-
<br />tance of instream flow needs of rare fishes has been recog-
<br />nized, and flow release from Flaming Gorge Dam was
<br />managed to improve spawning and survival of endangered
<br />fishes in 1986. Introduction of non-native fishes should be
<br />curtailed, and stocking of hatchery-reared natives consid-
<br />ered only after careful research (Tyus 1984). In the lower
<br />basin, preservation of free-flowing riverine areas and pro-
<br />tected refugia and management of non-native species are
<br />needed to maintain viable populations of native fishes (Wil-
<br />liams et al. 1985). Reintroductions ofrare native species and
<br />attempts to remove non-natives (Meffe 1983) should be han-
<br />dled in a responsible manner. Meffe's (1986) suggestions
<br />for genetically sound management of endangered fishes also
<br />deserve consideration.
<br />Public education programs on the condition of the river
<br />and its unique, jeopardized biota are also needed. Greater
<br />cooperation between all political entities and agencies
<br />responsible for management of the system will be required
<br />if elements of that unique biota are to be preserved.
<br />
<br />Conclusion
<br />
<br />Research on the biota of the Colorado River System has
<br />been largely descriptive. Little is known regarding produc-
<br />tivity, yield, and economics of the system's fisheries.
<br />Despite calls for consideration and testing of ecological con-
<br />cepts (Carlson et al. 1979; Ward and Stanford 1983), only
<br />a few examples of such research exist for the system (Molles
<br />1980; Annear and Neuhold 1983). Ward et al. (1986) con-
<br />cluded that the Colorado system generally lacked the struc-
<br />tural and functional integrity of eastern woodland streams
<br />on which the river continuum concept is based. Continued
<br />research should be supplemented by rehabilitation of the
<br />system.
<br />The Colorado River has been drastically altered in less
<br />than a century of human activity, and ecological relation-
<br />ships have been changed most significantly in the past 50 yr.
<br />Stanford and Ward (1986a) stated that the future ofthis reg-
<br />ulated system depends on whether (1) there will be enough
<br />water to maintain desirable ecosystem values and (2) native
<br />and non-native fishes can co-exist. Welsh (1985) was con-
<br />vinced that a future water shortage will occur in the basin
<br />and that the upper basin states, which have not yet developed
<br />their allocations, will playa major role in determining its
<br />timing. The basin is expected to experience a surface-water
<br />shortage sometime after the year 2000 unless its water sup-
<br />plies can be augmented. Stanford and Ward (1986a) con-
<br />cluded that endangered endemic fishes are incompatible
<br />with stream regulation and non-native species and that
<br />future water shortages will preclude allocations for them
<br />and other ecological concerns. Alternative scenarios might
<br />
<br />234
<br />
<br />include legal provisions to protect or restore affected aquatic
<br />communities as a result of increased citizen awareness of
<br />and concern for natural values and species survival. Limits
<br />on humans population growth and development in the
<br />Southwest may also be imposed by water supply and/or
<br />other factors before the biota of the Colorado River system
<br />is significantly changed from its current status.
<br />
<br />Acknowledgments
<br />
<br />Special thanks are extended to W. L. Minckley and P. C. Marsh
<br />for contributing information on conditions in the lower portion of
<br />the Colorado River System. We also thank R. J. Behnke, B. D.
<br />Burdick, K. D. Fausch, L. R. Kaeding, C. W. McAda, H. M.
<br />Tyus, D. E. Snyder, R. A. Valdez, and J. V. Ward for manuscript
<br />reviews. W. E. Rinne and J. V. Ward provided unpublished litera-
<br />ture.
<br />
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