Laserfiche WebLink
1 <br />Management Implications <br />i <br />In general, we do not view northern pike a large threat to native fishes. We make this conclusion <br />based on a number of results from this study. First, the northern pike population is not considered <br />extremely large. Mark-recapture estimates suggest that the population is about 82 individuals <br />(plus/minus 35) for the Split Mountain to Desolation Canyon subpopulation of northern pike, <br />Over a 2.5 year period, only 37 individual pike were handled during an intensive, species specific <br />sampling regime. Thus, a conservative population estimate for the Ouray reach, subpopulation <br />' would be about 100 individuals. This density, coupled with the overall average diet composition <br />of only 5% Colorado squawfish results in an annual estimate of squawfish consumption of about <br />' 18.8 Kg or 8,098 1-yr old fish. While this number is substantial, we suggest that other nonnative <br />fishes such as smallmouth bass, channel catfish and green sunfish which are numerically much <br />more abundant are more likely to be have much larger depredation effects on the native fishes <br />(Growl, unpublished data). <br />Northern pike, while perhaps the most important nonnative predator in our system, do appear to <br />be hi hl susce ti 1 t h ni were able to reca ture most to ed <br />g y p b e o mec a cal removal activities. We p gg <br />' individuals repeatedly, suggesting that they have relatively constant homeranges. Indeed, home <br />ranges of northern pike averaged slightly less than 0.6 miles per month in this study. We also <br />did not observe any evidence for in situ reproduction. That is, we did not find any young-of-the- <br />' year or even yearling fish during our intensive sampling. These findings suggest that localized <br />' removal efforts should be highly successful for this species. <br />' 18 <br /> <br />