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<br />Task 4: Develop Recovery Goals <br /> <br />Task 4a: Designation Of Sub-Populations <br /> <br />Recovery goals will be developed tor each of the sub-populations shov.TI in Table 2. Each sub- <br />population represents a reach of river occupied by a discrete group of fish that complete their life <br />cycle within that reach; there may be some exchange of individuals with other sub-populations. <br />Designation of these sub-populations will be refined based on interviews with biologists. Sub- <br />populations for the upper basin were modified from those identified for the interim management <br />objectives (IMO's; Lentsch et al. 1997). Sub-population designations for the lower basin are <br />preliminary and are b~se~ on known management units for target species. These designations will <br />be tinalized following recommendations from biologists. <br /> <br />Task 4b: Minimum Effective Population Size <br /> <br />Minimum effective population size (Ne) is the number of adults in a population necessary to <br />maintain genetic viability and minimize the negative effects of inbreeding (Soule 1987, Allendorf <br />et al. 1997). A maximum of 1 % inbreeding rate is recommended for wild populations (Simberloff <br />1988). A minimum effective population of 1,000 adults is recommended for most animal <br />populations (Lynch 1996). However, Ne is likely to differ by species (Meffe 1986) and can be <br />calculated. based on known genetic characterizations. <br /> <br />We propose to use the existing literature on genetics of Colorado pikeminnow (Ammerman and <br />Morizot 1989. Gilpin 1993). razorback sucker (Buth and Murphy 1984, Buth et a1. 1987, Dowling <br />. <br /> <br />and Minckley 1993, Echelle 1991), humpback chub (Dowling and DeMarais 1993, DeMarais 1986), <br />and bony tail (Echelle 1991, Minckley et a1. 1989) to develop estimates ofNe, based on inbreeding <br />rates of less than 1 %. Minimum population size will be the basis for determining the number of <br />adults needed to maintain a genetic all-viable population. The population structure around this adult <br />number \-vill be developed based on fecundity. survival, and age. In cases where habitat is not <br />considered adequate. a metapopulation approach will be used to determine if a given sub-population <br />is capable of genetic exchange with other nearby sub-populations. <br /> <br />4 <br />