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<br />Diet Composition <br />Twenty-six northern pike were captured and examined for stomach contents from the Ouray <br />subpopulation during spring, summer and fall 1993 and spring 1994. Only one of eight pike <br />' ca tured in October fall 1993 contained re common ca C rinus car io . Sixteen of the <br />P ( ) P Y( rP~ YP P ) <br />18 pike sampled in spring contained prey. Juvenile Colorado squawfish (total length = 45-54 mm) <br />were only found in stomachs of age-4 northern pike (500-600 mm fork length), and represented <br />13% of their diet by wet weight (Figure 1). When averaged across all ages of pike, the diet <br />consisted of 5% juvenile Colorado squawfish, 72% other cyprinids (red shiners, Notropis <br />lutrensis; redside shiners, Richardsonius balteus; common carp, and unidentified cyprinids), 6% <br />suckers, 6% crayfish, and 11% mice. <br />One hundred thirty-two pike were captured from the Yampa River subpopulation in May through <br />November, 1987-1989 and examined for stomach contents. Thirty-four percent of the stomachs <br />were empty in spring, 14% were empty during the summer and 30% in autumn. Diet composition <br />was similar for both subpopulations (Figure 2) except that there was no evidence of squawfish <br />predation in the Yampa River. Young-of--the-year, 1- and 2-year old squawfish were not found in <br />the Yampa system during summer and fall. Because of their unavailability in this area, we did not <br />expect to find them in the diets. <br />10 <br />