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life stages of the rare fish. Various minnows have been introduced <br />intentionally as forage for sport fish or accidently from bait buckets into <br />the Upper Basin. Larger numbers of certain introduced fishes have been <br />correlated with lower numbers of some native fishes. For example, the red <br />shiner (Notropis lutrensis) is particularly abundant in the lower reaches of <br />the White River (Table 2, Green River (Table 3), and in certain habitats of <br />the Colorado River (Table 4). In these areas, the native species are not as <br />abundant. Management of sport fishes in the Upper Basin will require <br />management of forage organisms in a systematic way to minimize any potential <br />conflicts from competition. In fact, extra precautions may have to be taken <br />to ensure that recovery efforts are not hindered by stocking fishes that may <br />compete with or prey upon the rare fishes. <br />Moyle, Li, and Barton (1986) have summarized the detrimental impacts of fish <br />introductions on native species through competition and predation where the <br />native fish have become eliminated or nearly extirpated. More importantly, <br />they point out that introductions have altered fish communities throughout <br />North America and that numerous management problems have been created by the <br />resulting unstable fish communities. Magnuson (1976) summarized the problems <br />associated with animal introductions succinctly "as a game of chance". <br />Some management techniques to control nonnative species might include <br />regulation of streamflows. For example, Minckley and Meffe (1987) reported <br />that native fishes in the American southwest are favored by flooding in <br />streams. In another study, periodic, high flows in six unregulated Arizona <br />streams reduced the number of predatory sunfishes and catfishes while native <br />fishes were little affected (Meffe 1984). Streamflow manipulation will be <br />studied as part of the recovery implementation program for the rare Colorado <br />River fishes (U.S. Fish and Wildlife Service 1986). <br />The available information is sufficient to warrant caution in stocking these <br />warmwater predators or nonnative forage fishes in the Upper Colorado River <br />while recovery efforts for the rare Colorado River fishes are being <br />implemented. The studies outlined in the recovery implementation program <br />(U.S. Fish and Wildlife Service 1986) will provide information to be used in <br />making recommendations for recovery of the rare fishes. As knowledge is <br />acquired on the ecological requirements of the rare fishes and the <br />interactions of these fish with nonnative species, fishery management <br />practices can be adjusted when biologists are reasonably certain that the <br />outcomes will not have negative impacts on the rare fishes. <br />Although stocking of the rare Colorado River fishes will be a part of the <br />recovery effort (U.S. Fish and Wildlife Service 1986), recovery success to <br />develop naturally sustaining populations will depend on having available <br />suitable habitat to meet the ecological requirements of the rare fishes (Rinne <br />et al. 1986). Management practices will have to provide the best conditions <br />for survival of the rare fish, especially during the early years of life, <br />while reducing potential or actual competition and predation by nonnative <br />fishes. <br />Therefore, the FWS policy - "to oppose stocking of fish species that may <br />compete with or prey upon the rare fishes - will remain in effect until it <br />can be demonstrated that such introductions will have no significant impact on <br />the recovery of the rare fish. <br />10