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<:S-~ GQ.al Evaluate use of graded gravel pits connected to the river that seasonally flood during runoff and subsequently drain following runoff by sub-adult and adult Colorado squawfish and other native fish. Remove all nonnative fish captured by mechanical means from graded gravel pits that are connected to the river in the spring when they seasonally flood and in the summer when they subsequently drain. Obiectives 1. Determine the extent of use by sub-adult and adult Colorado squawfish and other native fishes of graded gravel pits that seasonally flood and drain and that are connected to the river immediately prior to, during, and immediately following runoff. 2. Determine if collecting nonnative fishes immediately prior to, during, and immediately following runoff from floodable and drainable ponds connected to the river can be an effective and feasible means to actively and consistently remove, control, and ultimately reduce the numbers of nonnative fishes on a river-reach scale and off-channel lentic habitats connected to the mainstem in the Upper Colorado River. 3. Determine nonnative fish use of off-channel, ponded habitats connected to the river. 4. Document the species, numbers, and biomass of nonnative fishes removed via mechanical means, i. e., nets. 5. Provide recommendations for the long-term use of this strategy for controlling nonnative fishes in floodplain habitats. V. Study area: Upper Colorado River in the Grand Valley near Grand Junction, Colorado, river mile 185.1 downstream to river mile.152.6. In the Upper Colorado River, the highest priority reach identified for recovery of endangered fishes and highest level of concern for nonnative interactions with native fishes was the stream reach between Government Highline Diversion Dam (river mile 194) to the head end of Lake Powell. 7