8121 - Laserfiche WebLink

Home Browse Search

o Accordingly, all proposed management activities in the Upper Colorado ' River Basin will be evaluated with consideration to potential genetic risks to endangered fish stocks, especially if the risks include genetic losses that may become irreversible. ' o Irreversible loss of genetic diversity in endangered fishes in the Upper Colorado River can be avoided or minimized through rational and systematic planning. ' o Adaptive management (Boyce 1993; Ludwig et al. 1993; Walters and Hillborn 1978) should be employed in recovery of the endangered ' fishes in the Upper Colorado River Basin. Since there is no "track record" for determining if recovery actions are correct for the upper basin, all actions should be thoroughly evaluated so actions are completed systematically and adjustments or refinements made as ' needed to obtain the desired response from the endangered fishes. E. Opportunities for Effective Management of Genetic Resources. Some ' recovery actions have higher priorities than others with regard to protecting and maintaining the genetic diversity of endangered fish stocks in the Upper Colorado River Basin. Application of management opportunities (Box 2) will ensure that recovery is done in a way that will maintain genetic diversity of endangered fish stocks or cause the least adverse affects on these stocks. Recovery emphasis will be on preserving and enhancing natural habitats so that the endangered fishes can be recovered from wild stocks. However, captive propagation and stocking can be useful tools in recovery efforts where wild stocks are low in number (e.g., razorback suckers in the upper Colorado River and Colorado squawfish in the Gunnison River between Redlands Irrigation Diversion Dam and Delta, Colorado) and where the endangered fish have become extirpated because of habitat alterations (e.g., Colorado squawfish in historic habitat upstream from the Highline Irrigation ' Diversion Canal to Rifle, Colorado and bonytail throughout its historic range in the upper basin). ' F. Production Strategies. Three production strategies can be used to recover endangered fishes (Riggs 1990): ' 1. All Natural. Establish a refuge or genetic conservation area to manage a natural or naturalized population or stock without any kind of captive production or supplementation. ' 2. Supplementation. Rebuild natural spawning while minimizing genetic risks through captive propagation and supplemental stocking to augment declining populations or stocks or to restore extirpated ' populations or stocks. 3. All Captive-Reared. Maximize hatchery contribution to maintain populations or stocks with little or no expectation of restoring natural production.