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This annual report presents YOY Colorado squawfish and subadult-adult Colorado <br />squawfish data collected from the Green, Colorado, White and Yampa rivers in 1996. <br />YOUNG-OF-YEAR COLORADO SQUAWFISH <br />Sampling Reaches <br />Four important nursery areas in the Colorado (Reach 1, RM 0-110; Reach 2, RM 135- <br />170) and Green (Reach 3, RM 0-110; Reach 4, RM 200-220) rivers are sampled during the <br />YOY Colorado squawfish portion of ISMP (Figure 1). These four reaches compose about <br />709b of the known distribution of YOY Colorado squawfish in the Green River and about <br />80 % in the Colorado River. <br />Methods <br />Each reach sampled was divided into 5-mile subreaches which formed the basis for the <br />sampling design. A sampling crew began at the top of each reach and traveled downstream <br />` until it reached a suitable backwater (surface area of at least 30 m2 and maximum depth of at <br />least 30 cm, unless the water was turbid) which it sampled with a 4.6-m-long, 3-mm-mesh <br />seine. Two non-overlapping seine hauls were taken in the backwater. Effort was recorded <br />as area swept by the seine. Colorado squawfish were measured, counted, and released alive <br />if they were large enough to be reliably identified. Fish of other species that were also large <br />enough to reliably identify were counted and released. All remaining fish in the first sample <br />were preserved for later identification in the laboratory to check for Colorado squawfish too <br />small to be identified in the field. Non-target fishes were later counted in the laboratory for <br />this sample only. Investigators then proceeded downstream to the next suitable backwater <br />which was also sampled with two non-overlapping seine hauls. Colorado squawfish were <br />measured, counted, and released alive. No other fish from the second backwater were <br />preserved or counted for ISMP. However, investigators (WRE) in Reach 2 preserve and <br />count all fish collected in all samples. These data are reported as well. <br />2 <br />