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We captured two tagged northern pike in this study. These adult fish (594 <br />and 820 mm TL) were tagged by Colorado Division of Wildlife personnel in the <br />Yampa River in 1982 and 1988 (T.P. Nesler, E.J. Wick, personal communication). <br />One fish had moved about 110 km between 15 April 1982 - 10 May 1983 when we <br />recaptured it in the Yampa River at km 18.4. The other pike had travelled 78 <br />km from 16 June 1988 to 23 May 1989, when it was recaptured at km 4.8. Growth <br />of these fish averaged only lOmm TL. <br />Walleye were also captured in the upper Green River (90%; n=50) and <br />averaged 511mm TL (range 395-686mm). These fish were presumed juveniles and <br />adults, based on size (Carlander 1969). Walleye was more widely dispersed than <br />pike, and was usually captured in a variety of slow shoreline runs, usually <br />associated with emergent or bank vegetation. One ripe female walleye (577mm <br />TL) was captured in the upper Green River on 15 May 1984 at a water <br />temperature of 13°C. We captured one tagged walleye at the mouth of the <br />Duchesne River on 21 May 1984. This fish was tagged by BIO/WEST Incorporated <br />on 13 April 1979 at a point about 37 km upstream in the Green River (L. Crist, <br />personal communication). This fish grew about 62 mm TL in five years. <br />Foods <br />Northern pike stomachs (n=123) were usually empty (54.5%), but of the <br />remainder, 97.6% contained fishes (Table 2). Red shiner, Notroais lutrensis, <br />and fathead minnow, Pimephales promelas, were most frequently consumed of nine <br />non-native fishes, and flannelmouth sucker, Catostomus lati~ nnis, bluehead <br />sucker, C. discobolus, and speckled dace, Rhinichthys osculus, were the <br />native fishes consumed. Other prey items included a leopard frog, Rana <br />i iens, a king snake, Lampropeltis spp., and detritus. Thirteen stomachs <br />(10.6%) contained fish remains that could not be identified. <br />5 <br />