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ECOLOGY AND CONSERVATION OF NATIVE FISHES IN THE UPPER COLORADO RivER BASIN 187 Conservation populations continue to be found mainly in short headwater stream sections. Rangewide Conservation Agreement for Roundtail Chub, Flannelmouth Sucker, and Bluehead Sucker Six basin states signed a conservation agreement in 2004 (Colorado Fish and Wildlife Council 2004) to expedite implementation of conservation measures for roundtail chub, flannelmouth sucker, and bluehead sucker, and to ensure persistence of these species throughout their ranges. Signatories include Arizona, Colorado, Nevada, New Mexico, Utah, and Wyo- ming. Each state will develop conservation and man- agement strategies for any or all three species that occur naturally within its authority. Each signatory agrees to (a) develop and finalize a conservation and management strategy, (b) establish and/or maintain populations of all three species to ensure persistence, (c) establish and/or maintain viable metapopulations, and (d) identifY, significantly reduce, and eliminate threats. It is believed that conservation actions to pro- tect and enhance these species and their habitats will contribute to conservation of other native fISh species with similar distributions. Conservation and Recovery Prospects Colorado Pikeminnow According to the 2002 recovery goals (U.S. Fish and Wildlife Service 2002a), recommended crite- ria for recovery and long-term conservation of bonytail are: 1. Finalization and implementation of site- specific management tasks to minimize or remove threats to attain necessary levels of protection. 2. Maintenance of an upper basin metapopu- lation with two genetically and demo- graphically viable, self-sustaining popula- tions, one each in the Green River subbasin and upper Colorado River subbasin, as well as the San Juan River subbasin, if target numbers are not met in the upper Colo- rado River subbasin. Each population is maintained such that: · trends in annual adult (age 7 +) point esti- mates do not decline significantly, · mean estimated recruitment of age- 5 and age-6 naturally produced fish equals or exceeds average annual adult mortality, and · each annual point estimate for the Green River subbasin exceeds 2,600 adults. Habitat of Colorado pikeminnow in the lower basin is too fragmented and modified to allow completion oflife history needs, and recovery of this species in the upper basin is believed to provide long- term species viability. Colorado pikeminnow persist as self-sustain- ing populations in the Green River and upper Colorado River subbasins, and concerted efforts are underway to restore the species in the San Juan River subbasin. Preliminary numbers of adults in 819 km of the Green River subbasin range from about 2,300 in 2003 to 3,100 in 2001; and from about 450 in 1992 to 780 in 2003 in 282 km of the upper Colorado River subbasin. Numbers of young and juveniles vary within and between years. Populations in the Green River and upper Colo- rado River subbasins increased following a series of wet years during 1983-1986, and a popula- tion viability analysis declared that the species was viable for 200 years (Gilpin 1993). Similar pulses in recruitment were seen following subsequent high water years (e.g., 1993). These population in- creases appear linked to high water years, and are attributed to high channel reshaping flows that di- versified habitat, cleansed the substrate of sediment, infused large amounts of food into the river, and diminished nonnative fish populations (Osmundson and Burnham 1998). Reoperation of Flaming Gorge Dam at about the same time provided less fluctuating flows in summer that stabilized nurs- ery backwaters and increased survival of young. An apparent recent decline in Colorado pikeminnow remains unexplained but may be attributed to pe- riods oflow flows since the late 1980s and drought conditions since 2000. This drought has allowed increases in nonnative predatory fish, and popula- tions of most native fish have declined (Anderson