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<br />upstream of Government Highline Diversion Dam (Anderson 1994). Northern <br />pike (Esox lucius), red shiner (Cyprinella lutrensis), and sand shiner <br />(Notropis stramineus) have not been identified upstream of Government <br />Highline Dam on the Colorado River (Anderson 1994). Only 20 adult <br />northern pike were caught upstream of Redlands Diversion Dam in 1992 and <br />1993 during an intensive inventory of the Gunnison River fish community <br />(Burdick 1995). Unfortunately, fathead minnows (Pimephales promelas), <br />red shiner and sand shiners are prevalent in the Gunnison River (Burdick <br />1995); however, stocked razorbacks should be large enough to overcome <br />any predation or competition from these species. <br />These two areas are the upstream reaches of historic habitat for <br />razorback sucker. Because the young fish are expected to move <br />downstream, they will undoubtedly populate downstream reaches as well. <br />By stocking the fish at the upper limits of its range, we can expect to <br />eventually populate the entire river system. Also, the young fish will <br />be able to select low-velocity habitats that they encounter in the <br />broad, floodplain valleys downstream from the release points before <br />being carried into canyons where quiet-water habitat is limited. The <br />specific release points are: Gunnison River - a three-mile reach <br />downstream from Hartland Diversion; and Colorado River - a five-mile <br />reach beginning near Rifle, Colorado. <br />Limited numbers of fish available for stocking in early periods of this <br />study require prioritization between the two stocking sites. The <br />Gunnison River should have priority over the Colorado River for several <br />reasons: (1) Interim flow recommendations made for studies related to <br />the Aspinall Biological Opinion should benefit the species; (2) Removal <br />of non-native predators from the Gunnison River is ongoing and intended <br />to directly benefit survival of'young razorback suckers; (3) The river <br />is smaller than the Colorado River, which should mean that fewer fish <br />are needed and, secondarily, the area to be monitored is smaller; (4) <br />Fish will still be able to move downstream and populate the Colorado <br />River; (5) Fish passage will soon be constructed at the Redlands <br />Diversion which will allow fish to move back upstream if desired; and <br />(6) Field studies at the confluence of the Gunnison and Uncompahgre <br />rivers are an important component of the proposed chemoreception <br />studies. <br />6. Time of Release <br />The fish will be stocked in either August or September. The intent is <br />to release the fish with sufficient time to acclimate to the riverine <br />environment before water temperatures decrease in late fall and winter. <br />This period is the earliest that YOY fish could be released after being <br />produced the previous spring. Also, streamflows are lowest at that time <br />of year so fish reared in ponds or floodplain habitats will not be <br />immediately subjected to high spring flows and should become physically <br />conditioned for life in the river prior to high flows the following <br />spring. <br />Timing may be varied for different groups to allow increased growth in <br />the hatchery and therefore allow comparison among size groups. Also, <br />9