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<br />increased hybridization in the upper basin (Maddux et al. 1993). Wild <br />fish stocks will be monitored through routine sampling and necessary <br />actions taken to avoid unnatural levels of hybridization. <br />V. GENETICS MANAGEMENT OF CAPTIVE STOCKS <br />A. Determining the Need for Captive Propagation and Stocking Endangered <br />Colorado River Fishes. Depressed endangered fish stocks that do not have <br />sufficient recruitment to achieve and maintain self-sustaining <br />populations or stocks may require captive propagation to produce fish for <br />experiments related to research studies and for augmentation or <br />restoration stocking (Williams et al. 1988). <br />Program needs for captive-reared endangered fish have been identified for <br />(1) genetic refugia and broodstock development, (2) research and <br />development, (3) information and education, and (4) augmentation or <br />restoration stocking (Wydoski 1994). Refuges serve a vital function in <br />maintaining endangered fish that may become extinct due to declines in <br />wild populations or from catastrophic risks and to hold wild fish for <br />broodstock development. Captive-reared endangered fish are needed for <br />research to conduct laboratory and field experiments related to <br />ecological requirements, habitat use, interactions with nonnative fishes, <br />response to contaminants in acute or chronic bioassays, homing (i.e., <br />olfaction and chemoreception studies), fish passage, taxonomy, anatomy, <br />and physiology as well as performance, fitness, and hereditary trials. <br />Endangered fish specimens are needed for use in public relations programs <br />and to educate the public about reasons for the fish being listed as <br />endangered and the program to recover declining populations. <br />Augmentation stocking may be required to provide a "jump-start" mechanism <br />to supplement fish in habitats where the wild populations are very <br />depressed. Restoration stocking will be necessary in river reaches where <br />stocks have been extirpated. Such stocking will be required to <br />reestablish the bonytail in the upper basin and may be needed to <br />reestablish other endangered fishes in unoccupied river reaches within <br />their historic range. <br />B. Genetic Risks Associated with Captive Propagation and Stocking. Planning <br />recovery efforts for the endangered fishes in the Upper Colorado River <br />Basin will be accomplished following a logical and systematic approach <br />(Box 3) that will prevent potential genetic risks. A genetic risk is <br />broadly defined as the sum of critical uncertainties associated with any <br />management action or inaction that may change the genetic diversity both <br />within and among wild stocks. Risk assessment consists of (1) estimating <br />risk and (2) managing risk (Lichatowich and Watson 1993). Major genetic <br />risks associated with captive propagation can be identified and reduced <br />through a careful assessment. Risk assessment will be addressed in <br />specific stocking plans on a case-by-case basis. The potential to manage <br />potential genetic risks to wild stocks will be essential for a "no <br />jeopardy opinion" under Section 7 consultation of the Endangered Species <br />Act. <br />16 <br /> <br /> <br />t <br /> <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br />J <br /> <br />1 <br /> <br />