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<br /> <br />o <br />o <br />(j <br />l'.\:'\ <br />en <br />Q) <br /> <br />D. Determine if hatchery-reared razorback sucker can lead researchers to <br />their wild counterparts. If captured, wild razorback sucker will be brought <br />into captivity and used to develop a captive broodstock for the San Juan <br />River. <br /> <br />All stocking efforts will be in compliance with the guidelines set forth in the <br />Genetics Management Plan now under development, following to the maximum <br />extent possible the sequential guidelines delineated by the Upper Colorado River <br />Basin Recovery Implementation Program Genetics Panel: <br /> <br />1 . Use locally-adapted stocks. If stocks of wild San Juan River <br />razorback sucker are available, progeny from paired matings of <br />these fish should be used. Progeny of San Juan River arm of Lake <br />Powell adults have been used in lieu of progeny of wild riverine <br />adults in all stockings in the San Juan River to date. <br /> <br />2. Use nearest neighbor. The nearest geographic neighbors to the <br />San Juan River are the Green and Colorado River populations. <br /> <br />3. Use razorback sucker from populations that have the most genetic <br />diversity. The Lake Mohave stock is the most genetically diverse <br />of any remaining razorback sucker population. <br /> <br />Throughout the 5-year augmentation effort, the selection of stocks to be used in <br />the augmentation will depend upon site and time specific conditions concerning <br />the host stock to be used. Various conditions in anyone year affecting either <br />the source populations or the San Juan River population can determine, upon <br />review by the Service and the San Juan Recovery Implementation Program <br />Biology Committee the source or sources of razorback sucker to be used in the <br />augmentation plan and the sites and numbers for stocking in the San Juan <br />River. <br /> <br />Based on the experimental stocking to date, large fish (<=400 mm total length) <br />should be used for stocking. Stocking of razorback sucker at the maximum size <br />attainable in one growing season (approximately 300 mm) may be acceptable, <br />and will make the most efficient use of hatchery space while still allowing for <br />production of adequate numbers of fish. <br /> <br />All razorback sucker will be tagged with Passive Integrated Transponder (PIT) <br />tags before release. Individual identification will allow researchers to distinguish <br />hatchery-reared fish and document their interactions with their wild counterparts <br />and other native species. All fish will be evaluated prior to stocking for <br />pathogens and parasites. Currently, hatchery stocks do not possess any <br />diseases not known to be present in wild fish. <br /> <br />The plan is intended to establish a population of 15,900 razorback sucker in the <br />159 miles of river between the Hogback Diversion Dam and Clay Hills boat <br />landing. <br /> <br />3 <br />