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in 1981 to identify potential spawning grounds. Similar collections were <br />made in the Green River in 1984 and 1985 to determine the distribution of <br />larvae in July and August. Sampling was done by dividing the river into 8 <br />km reaches and seining the first two backwaters in each reach. Sampling in <br />1984 and 1986-1988 was expanded to include seining at weekly intervals <br />during July and August below Yampa and Gray canyon spawning sites. Seine <br />samples were taken with 1-m long x 1-m deep seine with 0.63 mm2 mesh. <br />Drift netting was conducted about 25 km below the two spawning sites in <br />June and July 1986-88: in the Yampa River near the confluence of the <br />Yampa and Green rivers, and in the Green River immediately below Gray <br />Canyon (Figure 1). Each net was suspended in the river channel by <br />attachment to metal fence posts. Nets were set for about one-half hour <br />duration at 0600, 1200, 1800 and 2400 hours. Water velocity was recorded <br />at each location and sampling period with a Marsh-McBirney Model 2011 <br />current meter. <br />All larvae were preserved in 5% buffered formalin solution and sent to <br />the Larval Fish Laboratory at Colorado State University, Fort Collins, <br />Colorado, for identification. <br />Postlarval collections.-Postlarval Colorado squawfish (25-70 mm TL) <br />were sampled with 5-m long x 1-m deep seine of 3.2 x 4.8 mm woven mesh in <br />September and October 1979-1985 and 1987-1988 by use of a systematic <br />sampling design. A stratum was selected at random and the first two <br />backwaters encountered in each 8.0 km reach of that strata were seined. <br />Sampling then proceeded downstream in sequence. Colorado squawfish were <br />counted and measured to the nearest mm TL. All other fish species were <br />counted and placed in 10 mm-length classes. The area seined,. depth of <br />5 <br />