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decrease mortality in the Green River due to predation by nonnatives. In the San Juan River, recapture rates have been greater for larger stocked razorback suckers (Ryden ~ 2000). Marsh and Brooks (1989) stated that stocking razorback sucker in the 300 mm TL size range may enhance post-stocking survival. However, if numbers of northern pilce (Brunson pers. comet) and walleye (Meismer pers. comm.) are increasing in the Green River, then this increase in large predatory fish may lead to some adult mortality. ~ Chemoreceptive imprinting may be necessary for razorback sucker to return to spawning sites. It was determined by Scholz et al. (1992, 1993) that the critical period for chemoreceptive imprinting is at the hatching or swim up stage. Unless provided an artificial chemical cue to imprint upon, hatchery raised razorback suckers may imprint to the hatchery water. Scholz and Haines (1997) did not find much success with artificial ~ imprinting in a laboratory environment. Thus, the associated risks aze that hatchery spawned razorback suckers may be imprinted to the hatchery water unless artificially imprinted with a synthetic chemical and/or artificially imprinted razorback suckers may fail to return to adequate spawning habitat when provided with artificial chemical cues (as discussed in Ryden 1997). However, recent collections of stocked razorback suckers on i the Jensen spawning bar provide evidence that hatchery raised fish will return to spawning sites (Modde pers. Comm, Brunson pers. comm.). Bonytail ~ Bonytail are considered a Priority 2 species for augmentation/restoration efforts (Czapla 1999). Within that species priority, the upper basin stock of bonytail is rated Priority 1. The Genetics Management Plan directs the use of bonytail brood stock located at Dexter National Fish Hatchery for bonyta~7 propagation efforts at Wahweap State Fish Hatchery. Furthermore, Wahweap State Fish Hatchery has developed a bonytail brood stock from the fish. supplied by ~ Dexter National Fish Hatchery in past years. This brood stock will be used to provide for the bonytail stocking objectives when Dexter National Fish Hatchery can not provide the necessary larvae. Use of this facility to propagate bonytail in accordance with this plan will be detailed in the Facility Operations Plan (Czapla in draft). ~ Bonytail (ir-16,280) will be stocked for seven consecutive years in numbers that will allow achievement of a minimum viable population of 4,500 fish among three locations in Year 10 (Tables 1 and 2). In addition, these populations will have a multiple age-class structure. In the absence of data, conservative survival estimates were used for bonytail in accordance with Biology Corntnittee discussion (Biology Committee, September 26-27, 2001; Table 2). Bonytail ~ stocked into the Green and Colorado rivers will be an average of 200 mm in length (150 mm minimum; Age-1+). past Utah Division of Wildlife Resource monitoring of stocked bonytail in the Green and Colorado rivers may indicate greater survival in ]anger fish stocked. Bonytail are expected to reach this stocking size after the second growing season. ~ Bonytail will be stocked into three reaches in the Green and Colorado rivers: middle Green River, lower Green River, and Colorado River. Bonytail will be stocked at these three locations in an attempt to meet the recovery goals of the Green River and Colorado River subbasins. Each reach will be stocked with one-third the annual tazget stocking objective (n--5,427). Stocking in the middle Green River will occur in the reach of river between Jensen and Ouray (RM 302-249). ~ 6