7226

• UCREFRP Catalog Number: 7226
• Author: Kaeding, L. R. and D. B. Osmundson.
• Title: Slow Growth of Colorado Squawfish in the Upper Basin and Its Effect on Recovery.
• USFW Year: 1986.
• USFW - Doc Type: \
• Copyright Material: YES

"Fast'
(95% per year,
early-life
mortality)
W
N_
(A
Z
O
Q
J
4.
t]..
W
J
Q
W
u_
"Fast'
(99% per year,
early-life
mortality)
"Slow"
(95% per year,
early-life mortality)
"Slow"
(99% per year.
early-life mortality)
TIME
FIGURE 4. Comparison of theoretical growth of adult-female
populations of fast-growing, early-maturing Colorado squawfish
("fast") with those of populations of slow-growing, late-
maturing fish ("slow"), in a li-nitless environment, under
conditions of 95 or 99~ early-life mortality.
MANAGEMENT IMPLICATIONS
Agencies charged with management of Colorado squawfish in the
upper basin must develop programs to recover the species from near
extirpation. However, understanding both the causes of the
population decline and the factors limiting the population is
problematic and essential to such development. Although
extirpation of Colorado squawfish from former range is generally
agreed the result of widespread and often profoundly evident
effects of water-resources development, introduction of non-native
fishes, and poor land-use practices (Miller 1961, Minckley and
Deacon 1968, Minckley 1973), many upper basin river reaches show no
obvious man-induced physical change. A17 have been successfully
colonized by non-native fishes, however (Tyus et al. 1982).
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