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b <br />assessment. Stocking large numbers of hatchery razorback sucker could 1) <br />augment existing populations, and 2) restore self-sustaining populations in <br />currently unoccupied historic habitat. This might require implementing a <br />hatchery program to produce fish for stocking into the wild. Reestablishing <br />fish in historic reaches may require imprinting or conditioning fish to <br />certain sites with synthetic chemicals (e. g., morpholine, phenethyl <br />alcohol)(Tyus 1990). Long-term research would be conducted to determine <br />whether reproduction is occurring and whether younger fish are being recruited <br />to the adult population? Other questions include: do stocked adult fish <br />behave similarly or differently than their wild counterparts? Do they move <br />considerable distances or remain in the area of stocking? <br />PRE-STOCKING ACTIVITIES <br />Establishing A Broodstock/Refugia Population <br />Concurrent with basin-wide genetic studies, will be the need to develop <br />broodstocks from appropriate donor sources in order to protect and conserve <br />population genetic integrity. Studies are progressing to determine if <br />populations of razorback suckers from different locales are genetically <br />similar or different. Experimental stocking should not take place before <br />these studies are completed. This would help ensure that the genetic <br />integrity of each population is maintained. Given that no wild young or <br />juvenile fish are available and that only a few, wild adult razorback sucker <br />may be left in the upper Colorado River, it is vital to collect sufficient <br />numbers (about 30) of wild, adult fish and place them in protected refugia to <br />avoid population extinction and to preserve genetic variation within and among <br />populations. This should be accomplished by capturing and securing wild <br />17 <br />C