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lot is represented by a minimum of 10 adult females and 10 adult males. In the future, the 25 <br />family lots will be used in a 25 X 25 breeding matrix. Parental fish are stocked out after use; that is, <br />an individual fish is only used for production once. <br />The Wahweap State Fish Hatchery (Wahweap SFH) maintains a portion of the 1996 through <br />2001 year classes for backup of Ouray's Green River broodstock, but at this time they have no <br />production commitments for these fish. <br />Upper Colorado Mainstem/Gunnison River System <br />Minckley et al. (1991) reported that RBS abundance in Lake Powell was low. After <br />inundation of the riverine habitat, spawning aggregation locations in the reservoir were assumed to <br />be indicative of fish migration into the reservoir from the respective upstream tributaries. These <br />aggregations are referred to as the Colorado River arm, the San Juan River arm, and Dirty Devil <br />River arm populations. A few individual RBS were captured from the San Juan and Colorado River <br />arms of Lake Powell and used as initial founders for respective broodstocks at Ouray NFH, <br />Wahweap SFH, and Grand Valley facilities in the early 1990s; however, those wild populations are <br />now considered extinct. <br />With the exception of a few wild RBS in isolated off-stream ponds, and fish in the Colorado <br />River arm of Lake Powell, the wild population has been extirpated in the mainstem. The last <br />captured wild individuals from the mainstem river were taken into captivity in the late 1980s and <br />early 1990s. Seven of those wild adults were taken to Dexter in 1990, and spawned in 1991. <br />Efforts to develop an Upper Colorado River mainstem captive broodstock at Dexter were <br />unsuccessful. In 1993 a small population of razorback suckers were found in Etter Pond near <br />Debeque, Colorado, in an off-stream backwater in the Grand Valley area. Genetic analysis <br />suggested those fish were derived from very few individuals (perhaps only one female) and could <br />be full or half siblings. Buth et al. (1987) found RBS from Etter Pond had atypically high levels of <br />an allozyme variant common in flannelmouth sucker. Buth et al. (1987) also suggest that