9436

• UCREFRP Catalog Number: 9436
• Author: McAda, C. W.
• Title: Subadult and Adult Colorado Pikeminnow Monitoring; Summary of Results, 1986-2000.
• USFW Year: 2002.
• USFW - Doc Type: Recovery Program Project Number 22,
• Copyright Material: NO

7
6
5
-~ 4
~.
r 3
a 2
V 1
~-- 0
W
a 7
= 6
~ 5
~ 4
3
2
0
Upper Green River
------- ------------------------
i
86 87 88 89 90 91 92 93 94 95 96 97 98 99 00
Lower Green River
----------------------------------- --------- -
- -~--~---U-- ---------=--------
86 87 88 89 90 91 92 93 94 95 96 97 98 99 00
Year
FIGURE 4. -- Mean CPE (CPM/hr) of Colorado pikeminnow in upper (1, 2, and 3)
and lower (4 and 5) reaches of the Green River,1986--2000. Vertical bars represent 95%
confidence intervals; regression results are provided in Tabie A-9.
Colorado River. - The slope of the regression line for the Colorado River was
significantly greater than 0; however, visual inspection of the data shows two groups of years
when catch rates were uniform, with no consistent increase (Figure 5). Mean CPE fluctuated
around 0.25 CPM/hr in 1986-1990 and increased to about 1 CPM/hr in 1992-1998. Mean
CPE for most years in the early group were significantly different from years in the later
group, but the transition year of 1991 was not significantly different from years in either
group (Fisher's LSD; Table A-10). Mean CPE dropped in 1999 and 2000; mean CPE in 2000
was significantly less than CPE in 1995-1998, but CPE in 1999 was not (Table A-10).
Trends in CPE by reach were similar to the river-wide trend (Figure 6); low levels in
1986-1990 with higher levels in 1992-1998. However, CPE continued its upward trend
through 1999 in the upper river and didn't drop off until 2000. Mean CPE in the lower river
declined in 1999.
10