9438

• UCREFRP Catalog Number: 9438
• Author: Clarkson, R. W. and M. R. Childs
• Title: Temperature Effects of Hypolimnial-Release Dams on Early Life Stages of Colorado River Basin Big-River Fishes
• USFW Year: 2000
• USFW - Doc Type: Copeia
• Copyright Material: YES

CLARKSON AND CHILDS-TEMPERATURE EFFECTS ON FISHES

409

16 16' 16
X. texanus X. texanus X. texanus
12 ~ 12 age = 14 days 12 age = 41 days
8 8 8
4 4 4 ~
~
0 0 0
-4 I -4 -4
0 30 60 90 120 0 30 60 90 120 0 30 60 90 120

16 16 16
c::: C. latipinnis C. latipinnis C. latipinnis
<.9 12 ~d'Y' 12 age = 14 days 12 age = 41 days
C/) 8 8
C 8 ~8
t'tl
Q) 4 ~ 4 4 ~
~
0 0 0
-4 I I -4 I , -4
0 30 60 90 120 0 30 60 90 120 0 30 60 90 120

16 16
12 P. Jucius 12 G. cypha
age = 14 days age = 41 days
8 ~ 8
4 4 ~
0 ~ 0
-4 -4
0 30 60 90 120 0 30 60 90 120
Time (days)

Fig. 3. Mean specific growth rate (SGR) of early life stage big-river fishes reared at three temperatures.
Ages are days posthatch at initiation of experiment. Circles denote 10 C, squares 14 C, and triangles 20 C.

.J.

occurred at 12 C or 14 C at this age for either
species nor with older ages of either species.
Swimming behaviors, however, were lethargic at
all treatment temperatures for all ages. No mor-
tality attributed to temperature effects occurred
in any X. texanus or C. latiPinnis temperature
shock experiment.

DISCUSSION

Field observation (Miller, 1961; Vanicek et a!.,
1970; Kaeding and Zimmerman, 1983), labora-
tory experimentation (Marsh, 1985; Berry,
1988; Thompson et a!., 1991; and others), and
simulation (Kaeding and Osmundson, 1988)
convincingly demonstrate the negative effects of

cold water temperature (< 15 C) on life-history
parameters of native fishes of the Colorado Riv-
er basin. Our results also suggest adverse effects
of low temperature on early life stage growth
and development are similar across the species
examined. Physiological/behavioral effects (as
determined by cold shock experiments) are less
consistent.
Our research quantified the effects of water
temperature on growth of early life stage big-
river fishes: (1) mean ranks of SGR were signif-
icantly lower at both 10 C and 14 C compared
to 20 C controls on all sampling dates and in
all age comparisons; and (2) for X. texanus and
C. latipinnis, mean ranks of length and weight
were significantly different across experimental