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<br />marks) using the methods outlined in Haines and Modde <br />(1996). Fish movement between autumn and spring (prior to <br />spring runoff) will be assessed by recaptures during spring <br />population estimates and by sampling downstream an <br />additional 20 miles at the end of the 3~pass sample. CPUE <br />within study sites will be estimated by using ISMP selection <br />and sampling procedures to identify the first two backwaters <br />in each 5-mile reach. These backwaters will be sampled using <br />standard ISMP procedures, followed by standard capture- <br />recapture procedures. Consequently, comparison of CPUE and <br />population estimates will not be confounded by environmental <br />fluctuations or other sources of bias. <br /> <br />VII. Task Description and Schedule <br /> <br />1. Make a population estimate and determine catch per unit <br />effort in 20 mile reach of upper (rmi320- 215) and lower <br />(rmi 120-0) Green River in early October. <br /> <br />a. Make three sample passes. Mark approximately 400 <br />age-O Colorado squawfish within each 20 mile study <br />reach. Give a unique batch mark for fish captured in <br />five mile subreach (total of 12 different batch marks) . <br /> <br />b. Sample all backwaters and record location of <br />backwaters sampled, main channel and backwater <br />temperatures, size, and depth of backwater, and numbers <br />of marked and unmarked fish captured. Measure effort in <br />m2 seined. <br /> <br />c. Extend third pass sampling downstream 20 mile <br />(without marking fish) to determine if marked fish <br />drifted downstream during sampling. <br /> <br />d. Calculate number of age-O Colorado squawfish <br />occupying 20 mile study reaches, seining catchability <br />coefficients, and probability fish move varying <br />distances per day. <br /> <br />2. Make population estimates and catch per unit effort in <br />the same 20 mile reaches in' the upper and lower river in <br />early April, using procedures above. <br /> <br />3. Analyze data and write preliminary report by 15 Dee each <br /> <br />4 <br />