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' The importance of cyprinids in northern pike diets was higher in spring than in autumn, whereas <br />sucker importance was low in spring and increased in autumn (Figure 3). <br />Consumption Estimates <br />Model simulations predicted that a population of 1,000 northern pike would consume 188 kg of <br />Colorado squawfish per year, based on observed diet information wherein only age-4 northern <br />pike ate squawfish (Figure 4). Seasonally, the biomass of juvenile squawfish consumed by 1,000 <br />pike was highest during spring and summer, lowest in autumn (November-January), and <br />intermediate in winter (Febru -A ril . Numerical] -the hi hest redicted losses of a e-1 <br />~'Y p ) Y~ g p g <br />squawfish occurred during spring (59,097-1 g fish) followed by 21,885-2.8 g yearlings during <br />summer. If all predation on squawfish was directed exclusively on age-1 fish, 102,725 would be <br />lost annually to a population of 1,000 northern pike. However, these results should be viewed <br />with caution, given the uncertain accuracy of our diet information from a small sample of pike. <br />We explored the bounds of uncertainty regarding pike diet with additional model runs to simulate <br />different proportions of juvenile squawfish in the diet. All ages of northern pike were assumed to <br />consume Colorado squawfish as a constant proportion of their diet throughout the year. These <br />results were then compared with those of-the nominal simulation which used age-specific diet <br />' composition obtained from field data. Predicted consumption from the nominal run was <br />bracketed by simulations where juvenile squawfish represented a constant 3% (134 kg of <br /> <br /> ., <br />~ <br /> <br />