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m. REDUCE NONNATIVE AND SPORTFISH IMPACTS 24 GREENIDUCHESNE NONNATIVE FISH CONTROL This study win document possible management strategies to enhance survival of native fishes by determining the potentially most important fish predators by species,size, area(s) of use, and time(s) of use. Objectives are to determine: I) growth and survival of juvenile Colorado squawfish in backwater areas with. the use and with.out th.e use of cages; 2) the potentially most damaging size classes and species of nonnative fish predators: 3) the feasibility, in tenns of effectiveness and duration, of predator exclusion devices for minimizing mortality from nonnative fish predation; 4) when predator exclusions are most effective in minimizing mortality; and 5) if selective , predator removal (with gill nets, trawling, electrofishing, chemical application, or oth.er means) is a \Liable option, at least in localized areas. Recommendations: MANAGEMENT IMPLICATIONS A1; a result of the backwater exclusion experiment it appears th.at when we can successfully exclude non-native predators from backwater nursery areas, survival of YOY native fish and YOY . Colorado squawfish in particular may be greatly enhanced, At this intennediate spatial scale (backwaters), this cost effective predator removal technique needs to be explored further. We need to make a link between growth and survival ofYOY Colorado squawfish in these backwater exclusion experiments to overwinter survival ofYOY Colorado squawfish. 58 GUNNISON RIVER SELECTIVE NONNATIVE FISH REMOVAL Negative impacts from introduced fishes are one of several factors responsible for th.e decline of th.e endangered fishes. Some of these fishes have been introduced into th.e basin to provide angling opportunities for sportsmen. They have escaped from their release sites and occupied the mainstem rivers that provide critical habitat for the endangered fishes. One of these species, northern pike, occurs in low numbers in the Gunnison River where the Recovery Program is attempting to reestablish-Colorado squawfish and razorback sucker. Northern pike were stocked into Paonia Reservoir on the North Fork ofth.e Gunnison River and have escaped and moved downstream into Critical Habitat. They do not appear to be reproducing in the Gunnison River and their numbers are very limited. Yet a few individual predators such as pike could take a substantial toll on young razorback suckers planned to be stocked in the area. Because of the importance ofthe Gunnison River for reintroduction efforts and because of the relatively low numbers of pike, it is an ideal location for a study to determine if selective, mechanical removal of nonnative fishes is a viable option to reduce their numbers in small areas. Recommendations: Continue as planned. Assess results, A-19