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<br />002773 <br /> <br />3.2.2.2 Bony tail Chub <br /> <br />The development ofbonytail chub broodstock began in 1994 when 25 family lots offertilized eggs <br />were produced from the spawning of 50 adult (25 male and 25 female) bonytails at Dexter National <br />Fish Hatchery. Unfortunately, transfer of these eggs to Valley City National Fish Hatchery in North <br />Dakota was delayed due to inclement weather, resulting in the successful hatching of only three lots. <br />One additional lot was spawned at Dexter that year and transferred to Valley City. The four lots of <br />fish were reared at Valley City and transferred to Horsethiefin November, 1994. (U.S. Fish and <br />Wildlife Service 1995a) <br /> <br />No additional development ofbonytail broodstock has taken place, given that the razorback sucker <br />was given higher priority. Currently, 5 adult bonytail are being held in refuge at Horsethier, along <br />with the four family lots. As of November I, 1996, Dexter held the following quantities ofbonytail <br />chub: 354 - 1981 year-class F. adults from 7 fish in mixed matings; and 1,000 - 1996 year-class F. <br />Young-of-Year (YOY) from one female and 3 male Lake Mohave adults (Czapla 1996b). Wahweap <br />SFH may serve as a an alternate facility in production ofbonytail chub (Czapla 1997). <br /> <br />3.2.2.3 Humpback Chub <br /> <br />The development of brood stocks for the humpback chub have been hindered by the lack of available <br />wild adult fish. In 1991, 20 adult humpback chub were captured from the Black Rocks area of the <br />Colorado River and were transferred to Dexter NFH in New Mexico. They were placed in a pond <br />with Colorado squawfish. All 20 humpback chubs were absent when the pond was drained for <br />maintenance in March, 1992. There was speculation that the Colorado squawfish had eaten the <br />humpback chubs. <br /> <br />In 1995, 15 adult humpback chubs were again captured from the Black Rocks area and were placed <br />in a 0.25 acre pond at Horsethief SW A (US. Fish and Wildlife Service 1995b). These fish are being <br />maintained at Horsethief to prevent the possibility of catastrophic extinction. The collection of adult <br />humpback chubs from Westwater Canyon will be postponed since there is no genetic data to indicate <br />that the two stocks are separate (Czapla 1997). No plans are currently being implemented regarding <br />the development of brood stock at Horsethief(Baker 1996). No brood stock have been developed for <br />other presumptive stocks of humpback chubs (Yampa, Desolation-Gray Canyon, Cataract Canyon, <br />Westwater Canyon). <br /> <br />3.2.2.4 Razorback Sucker <br /> <br />Green River Presumptive Stock: The brood stock for Middle Green River razorback sucker is being <br />developed at Ouray Endangered Fish Culture Experiment Station (EFCES) in Utah. In 1993, 13 pairs <br />were mated from 2 females and II males. Following a meeting of the Genetics Panel in 1994, it was <br />recommended that Ouray use the 25 x 25 paired matings breeding strategy in order to minimize <br />inbreeding. As a result, through the end of 1996, Ouray has produced 4 of the 25 required lots <br />requested under the 25 mated pair genetics plan. (pruitt 1996b) <br /> <br />13 <br />