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I I I I I I I J I t I I 1 I I I I I I 3 sampling was done by electrofishing along both shorelines of all reaches using a 17 foot flat bottom John-boat with a 4500 watt generator and droppers controlled by a VVP-15. Electrofishing crews began at the upstream end of each sub-reach and moved downstream at a steady pace. Backwaters, tributary mouths and other habitat features were sampled once as the crew proceeded down stream. Sampling time was measured to the nearest second on an elapsed time clock. All captured Colorado squawfish, humpback chub, razorback suckers and other native fish were measured for total length and weighed. Previous to 1989 they were also tagged with a numbered carlin tag before release at the capture site. Squawfish observed but eluded capture were also recorded. Total numbers of northern pike, walleye, large and sma11mouth bass, and green sunfish captured were also recorded. Post Larval. Aqe-O Colorado Sauawfish Monitorinq Post-larval squawfish monitoring was conducted between September 20 and October 10 each year. One river reach each was sampled on the Green River from the town of Green River, 120 rivermiles downstream to the Green/Colorado confluence and on the Colorado River from cisco downstream to the confluence. Sampling was done with 1/8 inch ace-mesh beach seines, 15 feet long by 4 feet deep. Each river reach was divided into 5 mile sections. Sampling crews began at the upstream 5 mile section and travelled downstream until they located a suitable backwater, at least 30 m2 and 1 foot deep at its deepest point. This was called the primary backwater. The backwater was then sampled with 2 non-overlapping seine hauls. The crew then travelled downstream until they located a second suitable backwater in the same 5 mile segment. The secondary backwater was sampled in the same manner as the primary backwater. If a secondary backwater was not found in the 5 mile segment, no additional sampling was done. This sampling procedure was then repeated in each 5 mile segment. All young-of-the-year (YOY) Colorado squawfish that were large enough to reliably identify in the field were measured in total length, counted and released alive. All other species collected in the first seine haul in each 5 mile reach were either identified and counted in the field, or preserved and later identified in the laboratory or by the Larval Fish Lab in Fort Collins, Colorado. The remaining samples were searched for Colorado squawfish only. Physical measurements (length, width and depths) were taken of each backwater and sampled area to be used in calculating a catch per unit effort (CPUE) (fish per 100 square meters).