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occurred in the Yampa River rather than an upstream reservoir. Nesler (1995) removed northern pike from backwaters in the Juniper, Maybell, and Lily Park reaches and reported a general decrease in catch rates for the three sites during the 4-year study. He concluded that it would be possible to reduce the northern pike population in the Yampa River by mechanical removal. Tyus and Beard (1990) removed 58 northern pike from the Green River over a 5-year period to investigate food habits. They reported a gradual increase in numbers collected during the study period, but effort may have varied from year to year. The Interagency Standardized Monitoring Program (ISMP) reported a decrease in pike numbers in the same area during 3 years when the two studies overlapped (McAda et al. 1994). It is not clear why there are discrepancies in the two data sets, but the decrease in ISMP catch rates may simply reflect the removal efforts of Tyus and Beard (1990). As in the Gunnison and lower Yampa rivers, northern pike do not reproduce in this reach of the Green River and recruitment is from subadults and adults moving into the area. Lentsch et al. (1996) reviewed the literature to evaluate options for selective control of nonnative fishes in the Upper Colorado River Basin. They felt that it was possible to reduce northern pike abundance in the upper basin by targeting areas where they are common or congregate for spawning. However, in habitats where successful reproduction occurs, attempts to reduce northern pike populations by mechanical means have been relatively unsuccessful (reviewed by Nesler 1995). The Gunnison River is historic habitat for razorback sucker, but no wild fish have been collected there since the mid 1980's (Burdick 1995). However, it is listed as Critical Habitat for the species (USFWS 1994) and preliminary attempts to reintroduce razorback sucker to the Gunnison River have begun. About 300 7-15-em-long fish were stocked in fall, 1995 and about 300 30-40-cm-long fish were stocked in fall, 1996 (Burdick and Bonar 1997). Stocking rates are expected to increase in the future. These fish were stocked in backwaters and other quiet water habitats near Delta-the same habitats occupied by the northern pike before their removal. Based on northern pike gape data presented by Nesler (1995), razorback suckers in the first stocking would have been vulnerable to predation by all but the 14