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<br />002792 <br /> <br />6.4.1 Initial Stocking Efforts <br /> <br />Experimental stocking of razorback sucker in the Green River was first performed in September of <br />1988. A total of 1,879 razorback sucker were tagged and stocked during a 16-day period (Appendix <br />A). An additional 4,488 razorback were tagged and stocked into the Green River in September, <br />1990. One razorback sucker stocked in 1990 was recovered the following spring (Burdick 1992). <br /> <br />Five family lots containing 929 captive-reared razorback suckers were PIT -tagged and stocked into <br />the Middle Green River in October, 1995. The release was made with the assumption that the fish <br />would disperse downstream into the Jensen-Ouray reach of the Green River where suitable habitat <br />would be available. The following year, sampling efforts did not collect any fish from this stocking, <br />suggesting no survival occurred. In addition, 21 PIT-tagged razorback suckers from natural <br />propagation that survived in Old Charlie Wash were also stocked in October, 1995 into the Middle <br />Green River at the same location. (U.S. Fish and Wildlife Service 1995b) <br /> <br />An experimental plan to evaluate stocking to augment or restore razorback sucker in the Upper <br />Colorado River was accepted by the Recovery Program in the spring, 1992 (Burdick 1992). That <br />experimental plan proposed stocking small numbers (10-20 adults per experimental stocking site) of <br />hatchery or pond-reared fish to obtain information on (I) dispersal, movement, and distribution <br />following stocking; (2) survival of hatchery or pond-reared fish; (3) habitat use; (4) potential <br />spawning areas; and (5) growth (Burdick et at 1995). <br /> <br />This plan was partially implemented. In the spring of 1994, 41 adult razorback sucker were captured <br />from Etter Pond near Debuque, Colorado, and implanted with radio transmitters. Twenty radio- <br />tagged razorback sucker were stocked in the Upper Colorado River and 21 were stocked in the <br />Gunnison River (Appendix A). The results of this stocking were not promising. In September. 1995, <br />only five of those fish were still alive. An additional four adult razorback sucker from Etter Pond <br />were radio tagged and held in refugia ponds at Horsethief SW A until being released in the Gunnison <br />River in October, 1995 (Burdick et at 1995). <br /> <br />Additional razorback suckers from 1994 matings were brought into Horsethief SW A ponds in June, <br />1995. During the summer, these fish suffered from various diseases. However, when the water <br />temperatures cooled below 70oF, treatments were more effective and they were able to put on some <br />growth. In October of 1995, 316 of these fish were stocked in the Gunnison River downstream of <br />the Hartland Irrigation Diversion Dam. (U.S. Fish and Wildlife Service 1995b) <br /> <br />6.4.2 Experimental Stocking Plan in the Upper Colorado and Gunnison Rivers <br /> <br />In November, 1995, a stocking plan for razorback sucker in the Upper Colorado and Gunnison Rivers <br />was developed (Burdick et at 1995). This stocking plan provided the rationale to reintroduce <br />razorback sucker in the Upper Colorado River (Rifle, Colorado downstream to its confluence with <br />the Green River: river miles 241-0) and Gunnison River (river miles 68-0.7) with the intent of <br />reestablishing a population between the years 1995 and 2000. The short-term goal of this initial <br />stocking effort is to establish an adult population of about 10 adults per river mile of the two rivers. <br />The long range or ultimate goal is to establish self-sustaining populations in both the Colorado and <br />Gunnison Rivers. (Burdick et at 1995) <br /> <br />32 <br />