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Results and Discussion Distribution and Abundance During 1993, gmean CPE was greater in reaches 1, 3 and 4 than it was in 1992. However, it was still considerably lower than was observed earlier in ISMP (Figure 2; Table A-1). No YOY Colorado squawfish were captured from Reach 2 of the upper Colorado River for the first time since sampling similar to ISMP began in 1982 (Archer et al. 1985; McAda et al. 1994). In the lower Colorado river, gmean CPE increased to 0.41 fish/10 m2 from 0.23 in 1992. This value is the third highest catch rate observed in Reach 1 since ISMP began. It is only slightly less than 0.46 CS/10 m2 recorded in 1988, but considerably lower than 0.85 CS/10 m2 observed in 1986. Although fish were collected as far upstream as RM 80, most YOY Colorado squawfish were collected from the lower 40 miles of Reach 1 (Figure 3; Table A-2). In the lower Green River (Reach 3) gmean CPE increased to 1.4 CS/10 m2, after 3 years of lower catch rates (Figure 2; Table A-1). But CPE was still lower than it was during the first 4 years of ISMP. Most fish were collected from the middle third of the reach. Gmean CPE was 0.43 CS/10 m2 in the upper Green River (Reach 4), which was the fourth highest level recorded during ISMP. A prominent peak in abundance occurred in the middle of the reach, between RM 250 and 260 (Figure 3; Table A-2). ~ 1.2 w ~ .8 ~o U \ ,4 C L N~ 0 ~ p U ~ U ''"" ~' .4 mo O p .3 ~ O .2 O U .1 .. 0 Reach 1 Reach 3 L~ 86 87 88 89 90 91 92 93 6 4 2 0 1.2 .8 .4 0 86 87 88 89 90 91 92 93 _ Reach 4 86 87 88 89 90 91 92 93 Year Figure 2.-Geometric-mean CPE (Colorado squawfish per 10 m2 seined) for the four reaches sampled during fall, YOY Colorado squawfish monitoring, 1986-1993. Bars represent ± 1 SE. r 4 86 87 88 89 90 91 92 93 Year