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Given larger sample sizes, it would be useful to compare tkj's observed in this study to <br />past or future estimates and relate these to environmental factors. Such an analysis would give <br />greater insights into the basinwide dynamics of fish movement and would allow a more robust <br />evaluation of the interplay of individuals among population segments. One useful comparison <br />may be if Colorado pikeminnow use regulated and unregulated stream segments such as Lodore <br />Canyon in the Green River differently under different hydrologic conditions (Bestgen and Crist <br />2000; Kitcheyan and Montagne 2005). Additional empirical analysis of growth and movements <br />of Colorado pikeminnow, based on tag recaptures would also be useful to further understanding of <br />the ecology of Colorado pikeminnow in the Green River Basin, as was demonstrated by <br />Osmundson et al. (1997; 1998). <br />Analysis of transition rates may also be useful to understand the ecology of other fishes in <br />the Green River Basin. For example, historical and ongoing investigations into the distribution, <br />abundance, and movement patterns of northern pike in the Yampa River, Colorado, have yielded a <br />substantial number of tag recaptures (Kesler 1995). Analysis of those tag recapture data, and <br />estimation of Ws to determine whether northern pike in the Yampa River move from upstream <br />source reaches, may aid management of Colorado pikeminnow that occupy critical habitat in <br />downstream reaches. <br />CONCLUSIONS <br />• The sampling design fulfilled assumptions of the estimating model sufficiently well. <br />The level of sampling effort and numbers of fish captured supported a relatively realistic <br />estimating model that was useful to obtain relatively reliable abundance estimates and other <br />demographic parameters for Colorado pikeminnow in the Green River Basin. Higher <br />58