7399

• UCREFRP Catalog Number: 7399
• Author: Valdez, R. A., P. B. Holden and T. B. Hardy
• Title: Habitat Suitability Index Curves for Humpback Chub of the Upper Colorado River Basin
• USFW Year: 1990
• USFW - Doc Type: Rivers
• Copyright Material: YES

HUMBACK CHUB JUV (75-259mm) - GREEN RIVER HUMPBACK CHUB JUV (75-259mm) - COlORADO/YAMPA
6
10 f (1,10.0,35.1,2.0,15.0)
0.8 0.8 n.44 4
Z ~ Z ~
0 0.8 0 0.6 3
~ Z ~ Z
W W
N 6 8 N :::J
:::; :::; 0
i= 0.4 W i= 0.4 2 W
a: a:
:::J ... :::J ...
0.2 0.2
0 0 0 0
0.0 1.0 2.0 3.0 4.0 0 10 20 30
DEPTH (feet) DEPTH (feet)
f (1,0.25,2.6,1.0,80.0) 16 1(1,0.25,2.6.1.0,80.0) 16
0.8 n.74 o.a n.74
Z ~ Z ~
10 0 10
0 0.8 Z ~ 0.8 Z
~ w w
8 N :::J
N :::; 0
:::; W
0.4 a: i= 0.4 W
i= ... :::J a:
:::J 6 6 ...
0.2 0.2
0 0 0 0
0.0 0.6 1.0 1.6 2.0 2.6 0.0 0.6 1.0 1.6 2.0 2.6
VELOCITY ('pa) VELOCITY ('ps)
0.8 n.32 0.8
~ Z
0.8 0 0.8
~ ~
N N
:::; 0.4 :::; 0.4
i= i=
:::J :::J
0.2 0.2
0 0
CI. 81 SA OR RU BO BE OT CL 81 SA OR RU BO BE OT
SUBSTRATE SUBSTRATE

1-74onlnt - GREEN RIVER
10

f (1,2.1,5.1,2.0,8.0)
n'.71 a

~
8 Z
w
6
w
4 a:
...

2

8.0
t(fMt)

4.0

o
6.0

30

f. &Exp(-&X)
G . 5.DOOOOOE-001

n.67

20 ~
Z
W
:::J
o
w
a:
10 ...

o

o.e 0.8 1.0
~TY (tpa)

n.71

I All BO BE OT
STRATE

and interim suitability in-
velocity, and substrate for
'Y) humpback chub (n =
; or individual fish).

FIGURE 4. Raw data and interim suitability in-
dex curves for depth, velocity, and substrate for ju-
venile (IUV) humpback chub in the Green River (n
= number or observations of individual fish).

development. Never-
ets were developed for
ause the experts per-
~rences in habitat, par-
ccupied between the
le Colorado and Yampa
~n River, average water
niles was 2.3 feet with
feet, while average ve-
vith a maximum of 2.6
4). Juvenile humpback
?rimarily over silt and
backwaters, eddies and
let was applied to the
uly through September

January 1990 J

(confidence rating of C), since no data were
available from other times of the year. Use
of this curve set was also restricted because
29 percent of the data were collected from
backwaters.
For the Colorado and Yampa rivers, av-
er~ge depth used by juveniles was 11.1 feet
WIth a maximum of 35.1 feet, and average
velocity was 0.6 ips with a range of 0 to
2.6 fps (Table 1; Figure 5). In contrast to
the data associated with the Green River,
these juveniles were found primarily over
boulders and bedrock with some sand and
silt substrate. This curve set applied to the
Colorado and Yampa rivers from July

[ R. A. Valdez et al.

FIGURE 5. Raw data and interim suitability in-
dex curves for depth, velocity, and substrate for ju-
venile (JUV) humpback chub in the Colorado and
Yampa rivers (n = number of observations or in-
dividual fish).

through September. It received a low con-
fidence rating (C) but was not restricted in
use by the general habitat constraint.

Adults

The most reliable microhabitat data
available for humpback chub was for the
adult life stage. These data were collected
from various locations of the Colorado,
Green and Yampa rivers using radiotelem-
etry, electrofishing, nets, and angling. Fol-
lowing considerable discussion, the ex-
perts decided to pool the data of all strata
and all three rivers since the habitat used

39 II~