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<br />. <br /> <br />threat of this predator to native fishes and that this minimal amount of effort will be <br /> <br />required at least until northern pike removal has been successful in the Yampa River. <br /> <br /> <br />· The following lines of evidence indicate our removal efforts are successfully limiting the <br /> <br />proliferation of northern pike in the middle Green River: a) declining trend in catch rates <br /> <br />within the Green River, which does not appear to be influenced by extraneous factors <br /> <br />(varying flows, net placement, equipment issues, or personnel turnover); and b) an age <br /> <br />analysis that indicates that northern pike encountered in the middle Green River <br /> <br />periodically immigrate from an upstream source as opposed to recruit from local <br /> <br />reproduction. <br /> <br /> <br />· Based on pre-project sampling and the findings of this study, northern pike continue to <br /> <br /> <br />concentrate in limited areas: the mouth of Brush Creek, Cliff Creek, Stewart Lake Drain, <br /> <br /> <br />Ashley Creek and Sportsman Drain (Table 4). We presume these areas provide the best <br /> <br /> <br />habitat for northern pike in the middle Green River. By focusing the majority of our <br /> <br /> <br />removal effort in these specific locations in the early spring when fish congregate <br /> <br />(presumably to spawn), we can successfully manage their densities. <br /> <br /> <br />· Catch rates tend to be higher with electro fishing and trammel netting; however, fyke nets <br /> <br /> <br />can be set and left for many days at a time. Thus, in terms of man-hours, fyke-netting <br /> <br /> <br />may be more cost effective in some years (when otters or variable flows are not a <br /> <br />problem). <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />30 <br /> <br />. <br />