9378

• UCREFRP Catalog Number: 9378
• Author: Nesler, T. P.
• Title: Recovery of the Colorado River Endangered Fishes
• USFW Year: 2000.
• USFW - Doc Type: Biological recovery goals and criteria for Colorado pikeminnow, Humpback chub, Razorback sucker & Bonytail.
• Copyright Material: NO

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data for these populations at the frequency specified (Table A-4). For population
structure requirements, the only difference between downlisting and delisting is an
increase in the percentage of the ~350 mm size category for the Colorado River
population and the ~601 mm size group for the Green River population.

Figure 1. Estimated population size based on 86% survival rates and annual
recruitment % for Colorado pikeminnow marked and recaptured with PIT tags in
the Colorado-Gunnison Rivers from 1991-1997.

Colorado-Gunnison CPM Pop. Estimate
86% survival rate

2000
1500

40

X.

30

ui
o 1000
:2

~

:

:

20 ';fl.

500

o

~ vX.. " X
hX ~ . .x - ~ ~

10

o

1991 1992 1993 1994 1995 1996 1997

Yea rs

. Estimate
~ "+95%

III "-95%
. "x. ,. % recruit@351

Figure 2. Estimated population size based on 86% survival rates and annual
recruitment % for Colorado pikeminnow marked and recaptured with PIT tags in
the Green-Duchesne-Price Rivers from 1991-1997.

Green River CPM Pop Estimate
86% survival rate

ui
o
:2

12000
10000
8000
6000
4000
2000
o

25

20

15

10

5
o

';fl.

199219931994199519961997

Year

. E stim ate
A "+95%

. "-95%
" ":x . %recruit@351

15