9702

• UCREFRP Catalog Number: 9702
• Author: Petersen, J.H., and C.P. Paukert.
• Title: Development of a bioenergetics model for humpback chub and evaluation of water temperature changes in the Grand Canyon, Colorado River.
• USFW Year: 2005.
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: NO

HUMPBACK CHUB BIOENERGETICS
967
TABLE 3-Corroboration results for the humpback chub bioenergetics model. The model was fit to laboratory and
field growth rates and p-values (proportionality constants that scale consumption according to food availability) were
determined. Two parameter sets were compared, one with satiation feeding (p = 1.0) and one with less than satiation
feeding (p < 1.0).
•o..
....
to 12
tperatures in
) before and
m and for a
using a tem-
ure data are
61 near the
ez and Ryel
prey were
wboration,
0 iterations
uming sati-
ing feeding
tiation (0.0
w satiation,
316).
for hump-
tiation and
:o field and
.eter values
lability es-
ameter val-
the growth
ration tests
age of 1.02
below sati-
d averaged
.laboratory
in p values
•owth rates
her growth
nigher tem-
r and more
simulations
ameter val-

ife stage

eriod

Starting
size (g)

Ending
size (g)
Specific
Temperature growth rates
(°C) (%/d) Estimated p-value
Parameters Parameters
fit with fit with
p = 1.0 p < 1.0

ources
Laboratory
Juvenile 90 d 0.07 0.14 10 0.3 0.61 0.41 2
90 d 0.07 0.32 14 0.7 0.82 0.60 2
90 d 0.07 1.02 20 1.3 0.98 0.73 2
146 d 3.7 3.6 12 0.0 0.66 0.34 3
92 d 3.6 5.3 15 0.2 0.92 0.57 3
238 d 3.5 t0.1 18 0.2 0.93 0.57 3
Little Colorado River
Subadult May-Jun 0.01 0.06 20 3.0 1.03 0.71 4
Jun-Jul 0.06 0.23 21 2.1 1.06 0.77 4
Jul-Aug 0.23 0.63 21 1.4 1.04 0.81 4
May-Jun 4.2 5.5 20 0.4 1.03 0.67 4
Jun-Jul 5.5 7.2 21 0.4 1.06 0.69 4
Jul-Aug 7.2 9.7 21 0.4 1.15 0.77 4
Age 1-2 4.7 26.6 5.0-26.5 0.2 1.10 0.68 5
Age 2-3 26.6 61.2 5.0-26.5 0.1 1.19 0.69 5
Age 3-4 61.2 97.3 5.0-26.5 0.1 1.24 0.69 5
Main-stem Colorado River
Age 1-2 5.4 19.8 9.1-11.5 0.2 1.18 0.75 1
Age 2-3 19.8 44.9 9.1-11.5 0.1 1.27 0.77 1
Average 1.02 0.66
Minimum 0.61 0.34
Maximum 1.27 0.81
a 1, Valdez and Ryel (1995); 2, Clarkson and Childs (2000); 3, Gorman and VanHoosen (2000); 4, Robinson and
Childs (2001); and 5, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, unpublished.
ues that were derived by assuming feeding was
below satiation in the laboratory growth experi-
ment. Parameter values for the bioenergetic model
for Gila spp.-humpback chub are provided in Ta-
ble 5.
As expected, optimum and maximum tempera-
tures for respiration and consumption were posi-
TABLE 4.-Energy density of prey (wet mass basis) and
average contribution to diet for subadult humpback chub
in the Grand Canyon. Diet is the average (ranges in pa-
rentheses) for spring, summer, and fall estimates (Valdez
and Ryel 1995). Energy density is from Cummins and
Wuycheck (1971).
Diet contribution
Average
Energy composition of
Prey taxon or category density (J/g) diet (%)
Simuliids 2,565 32(20-39)
Gammanis spp. 3,389 32(25-37)
Chironomids 2,744 7 (4-11)
Cladophora spp. 1,122 16(16-17)
Other aquatic invertebrates 3,176 1 (1-1)
Terrestrial invertebrates 3,050 12(4-19)
tively correlated (Pearson's product-moment cor-
relation coefficient), as we included a rule that
optimum temperatures could not be greater than
maximum temperature. The correlation coefficient
between RTO and RTM was 0.49 (P < 0.0001)
and between CTO and CTM was 0.48 (P <
0.0001). The respiration intercept (RA) was
strongly correlated with p (correlation coefficient
0.65; P < 0.001) and weakly correlated with RTO,
RTM, and CA (correlation coefficient < 0.2; P <
0.05). Other correlation coefficients were not sig-
nificant (P > 0.05).
Using the bioenergetics model, the growth rate
of juvenile and subadult humpback chub was pre-
dicted to respond in a complex manner to changes
in water temperature and food availability (Figure
3). When food availability was high, the maximum
potential growth rate for juvenile (4 g) and sub-
adult (115 g) humpback chub was at 27-28°C (Fig-
ure 3). At high food availability, the potential
growth rate declined steadily when water temper-
ature was below 25°C, but growth rate dropped
rapidly when temperature was greater than 29°C