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<br />General Recovery Program Support Action Plan <br />V. Monitor populations and habitat and conduct research to support recovery <br />actions, research, monitoring, and data management <br /> <br />Green River Action Plan? Mainstem <br />II. Restore Habitat <br />II.A. Restore and Manage Flooded Bottomland Habitat <br /> <br />Colorado River Action Plan? Mainstem <br />II. Restore Habitat <br />II.A. Restore and Manage Flooded Bottomland Habitat <br /> <br />Colorado River Action Plan ? Gunnison River <br />II. Restore Habitat <br />II.A. Restore and Manage Flooded Bottomland Habitat <br /> <br />III. Study Background/Rationale and Hypotheses: <br /> <br />The federally endangered razorback sucker Xyrauchen texanus was once widespread and <br />common throughout large rivers of the Colorado River basin, but only disjunct <br />populations and scattered individuals exist today (Bestgen 1990; Minckley et al. 199 I). <br />The largest extant riverine population occurs in the middle Green River system of <br />northeastern Utah and northwestern Colorado, but numbers of adults are low and <br />recruitment is minimal (Tyus 1987; Lanigan and Tyus 1989; USFWS 1991). Using <br />capture-recapture data collec~ed ~uring 1980~1988, Lanig~ and Tyus (1.989) estimated <br />the razorback sucker populatIOn m upper sectIOns of the mIddle Green River (RMI, . <br />346.8?176.3) at 948 fish (95% confidence interval, 758?1,138). Moddeetal. (1996) <br />reported a mean population size between 300 and 600 fish during 1980? 1992 for adult <br />razorback sucker in the middle Green River. They concluded that, although numbers of <br />fish are very low, this population is dynamic. Successful reproduction by Green River <br />razorback sucker was only recently confirmed through collection of larvae (data <br />summarized by Muth 1995) and early juveniles (Gutermuth et al. 1994; data <br />summarized by Muth 1995). Plans to evaluate stocking as a means to augment or <br />restore razorback suckerin the upper Colorado River basin have been developed (e.g., <br />Burdick 1992; Ryden and Pfeifer 1994; Modde et al. 1995) and initially implemented. <br />However, factors limiting recruitment of razorback sucker in the river system must be <br />determined before large-scale augmentation or re-introduction efforts are attempted. <br /> <br />Long-term monitoring ofrare fishes is needed to provide baseline data on species' status <br />and allow for future assessment of fish populations and their habitats (Williams et al. <br />1989). Restoration of razorback sucker in the Green and upper Colorado river systems <br />will initially focus on restoring and managing floodplain habitats to benefit razorback <br />sucker over nonnative fishes. It will employ both flow and non-flow alternatives, <br />stocking of razorback sucker, and control of nonnative fishes. Site- or reach-specific <br />evaluations will determine if intensively managed floodplain habitats can support <br />razorback sucker and assess the short-term success of stockings but will not necessarily <br />determine extent of recruitment into adult stocks. A monitoring pro~ram is needed to <br />track the status of razorback sucker in the upper Colorado River basm and evaluate . <br />population response to restoration activities. <br /> <br />Razorback sucker monitoring was initially included in the FY-1995 Capital Project's <br />umbrella proposal under the basin-wide evaluation component. Initial guidelines for <br />development of the monitoring program were identified in discussions with Pat Nelson <br /> <br />Page 2 of _ <br />