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1 I. EXECUTIVE SUNIIVIARY This "Genetics Management Plan" for endangered fishes in the Upper Colorado River Basin (Upper Basin) (1) identifies and classifies endangered fish stocks, (2) describes criteria for decisions related to genetics management, (3) establishes priorities for effective and rational genetics management for species and stocks, and (4) recommends management actions by species and stocks (such as, identified needs in stocking plans). t 1 1 1 t Eleven presumptive stocks of endangered fishes have been recognized in the Upper Colorado River Basin based on criteria involving geographic distribution, suspected or identified spawning sites, and movement or interaction. Criteria of genetic identification and characterization have been based on specific projects. The assignment of presumptive stocks for the Upper Basin is conservative to ensure preserving their genetic diversity because all stocks may be important in the recovery effort. Adaptive management will be employed by the Biology Committee to annually evaluate the plan and make appropriate revisions if warranted from new information. Three presumptive stocks of razorback suckers, five stocks of humpback chub, and three stocks of Colorado pikeminuow were identified for the upper basin. Bonytails aze razely captured in the upper basin, the probability of obtaining sufficient adults to develop a broodstock is remote. Therefore, restoration stocking efforts of this species will depend upon broodstock development from captive fish of Lake Mohave stock. Each presumptive stock is treated separately using the criteria for stock identification and is discussed by status, trend, and priority for upper basin. Management recommendations for endangered fish stocks from the Upper Colorado River Basin aze provided in Section VII "Recommended Management Actions for Endangered Fish Stocks in the Upper Colorado River Basin". The status and trends of presumptive endangered fish stocks in the upper basin were reviewed by the Biology Committee. The status of razorback sucker is considered critical in the upper basin because old individuals in current presumptive stocks aze declining rapidly and the stocks aze in danger of immediate extinction. Some recruitment occurs in the middle Green River stock but is probably not sufficient to maintain aself=sustaining population in that river reach. The bonytail is nearly extirpated in the upper basin and individual fish are captured very infrequently. Because of low numbers, a stock was not identified in the upper basin and it is recognized that broodstocks will have to be developed from Lake Mohave stock. The humpback chub stocks are appazently stable but the stocks are small and located in isolated deep canyon azeas of the upper basin. Stocks in Desolation-Gray Canyons and in the Yampa River exhibit large variations in phenotypes and maybe at risk from hybridization with roundtail chubs. The Colorado pikeminnow is considered stable for most presumptive stocks. The Upper Colorado River stock (upstream from Westwater Canyon) is very low in number and has been extirpated above irrigation diversion dams upstream from Palisade, Colorado. A presumptive stock in the Gunnison River above Redlands Irrigation Diversion Dam is extremely low in numbers and is declining. Successful use by subadult and adult Colorado pikeminnow of the Redlands fish ladder during the summers of 1996 and 1997 has demonstrated the utility offish passage projects. The Colorado pikeminnow in the Gunnison may now be supplemented by the fish using the ladder. Species priorities for propagation needs (including broodstock development, stocking plans, stocking of fish and hatchery facilities) were assigned on the basis of their current status and trends: razorback sucker - 1; bonytail - 2; humpback chub - 3; and Colorado pikeminnow - 4. Priority "1"indicates the highest priority and "4" the lowest priority. The assignment of priority 1 to the razorback sucker was based on the recovery potential of upper basin stocks. Assignment of priority 2 to the bonytail was based on the fact that only occasional captures of this species are made infrequently and broodstock development will rely on Lake Mohave stock. The humpback chub was assigned priority 3 because limited information on the status and trends of the various identified stocks suggests the stocks aze small but stable in localized river reaches. Finally, priority 4 was assigned to the Colorado pikeminnow because most stocks aze considered stable and recruitment has been documented for most stocks. The recommended target breeding strategy for propagation of the endangered Colorado River fishes is to mate 25 females with 25 males to produce 25 pedigreed family lots if sufficient adults are available and removal of adults from the wild will not jeopazdize the genetic characteristics of the founder stock. An inbreeding rate of