7378

• UCREFRP Catalog Number: 7378
• Author: Wydoski, R. S.
• Title: Potential Impacts of Alterations in Streamflow and Water Quality on Fish and Macroinvertebrates in the Upper Colorado River Basin.
• USFW Year: 1980.
• USFW - Doc Type: 77-147
• Copyright Material: YES

96

Lewis used a multiple linear regression in his analysis, with the number

of trout per pool as the dependent variable, and pool surface area, mean

depth, mean water velocity, percent cover, and total cover as the indepen-

dent variables. Pool surface area, volUllle, and depth accounted for little

of the variation in trout numbers in that study. Lewis suggested that

greater food drift, accompanied by increased water velocities, might sup-

port greater densities of trout. This concept is supported by the work of

other investigators (e.g, Chapman, 1966; Waters, 1969),

Some studies have focused on the microhabitat of salmonids which in-

eludes physical features in addition to water velocity and depth (Baldes

and Vincent, 1969). The brown trout used in this experiment remained near

structures on the bottom or along the edges of the shaded side of the ex-

perimental flume, The water velocity near the substrate was less than

that in the water column and, as the velocity increased, the trout moved

nearer to the substrate and became more dependent on irregularities on

the flume bottom, Differences appear to exist among species, and gener-

alizations are difficult to make concerning microhabitat of a single spec-

ies because it may vary with the size of the fish, and also seasonally

with behavioral adjustments to water level or to other physical features

of the stream.

Because the habitat requirements of saLmonids vary considerably with

the factors that have already been mentioned, much emphasis bas been

placed on spawning; consequently, this aspect of the life history is best

known for native trout species (Hooper, 1973; Smith, 1973; table 6).

Although the data summarized in table 6 have been obtained from various

locations, they are probably applicable tq the species of trout found in

the headwater streams of the Uinta and Rocky mountains.

~
~
o
...
f-<
~
c:
GI
'tI
'"
.
GI
t:lO:
>.
,Q
00
c:
'"
E
Q.
en
...
o
....
'tI
GI
...
...
GI
....
GI
...
p..
GI
...
~
~
III
...
GI
i
f-<
'tI
c:
III

III
.....
ra.
o
......
~ ~ cu
e'"'"
'"~B
~Illlll
8' Q. ...
. cu
Q.
m
~

.....
.
GI
.c
III U
GI C
N '"
'" ......
.

GI
~
al
...
~
.
,Q
~
.

'tI
cu
...
...
cu
....
cu
...
llo.

a
CU
N
'"
en
CU
~
III
...
~
.
.&l
~
en

III
>.
~
'"
U
o
..-I
CU
>
...
GI
~
III
:t
'tI
CU
...
...
CU
....
CU
...
llo.

t'
'"
U
o
o-l
Q)
>
...
GJ
~
.
~

00
.... c:
0....
![

f-< .

.
'ID
GJ
o-l

~
III ~
CU 0
.... ...
u""
CU

.....
0011'\
~II'\
1 I
~f"l
~~
......

.....
11'\0

..-I f"l
I I
11'\ 11'\
NN
. .
00
......

e
u
......

.....
00'ID

f"l.....
t t
f"l f"l
'ID\C

00
......

.....
U
CU
.
-
~
CU
CU
....
......

.....
.....0
o-l f"l
t 1
f"l0
o-l ..-I
......

.....
U
CU
.
-
9
......

.....
N ..-I
11'\ a-
I I
00
~f"l
......

.
U
CU
c:l
1
'"
U
o

~

.....
11'\
f"lll'\
11'\1
11'\
~
......

cu
o 00
'" ...
III
....-I
o
, ...
f"l 0
I ....
11'\ .....
N+.c
.0 .
o .....
......~....

cu
00
o ...
'" III
..-I
a
\C ...
. 0
..... ....
1
M+.....
\Co.c
. '.
00....
...... o-l ....

.....
o
f"l
.
o

.
..-I
......

.....
..-I
a-
1
o
f"l
......

>.
..-I
::I
.,

I>.
. ..-I
... ...
Q.1Il
< CU

'"
III
o
...
.c
'"
'"

97

.....
\CO
~II'\
1 1
f"l .....
~f"l
......

0.....
.., ..-I
CU
'tI >
c: III
III ...
. 00
CU
. c:
.......
III
00
U .
......f"l

o
'" .....
..-I
'tI CU
c: >
III III
III ...
00
CU
. e
... u
III
0\C
U .
...........

.....
o
f"l
.
N

.
o
......

.....
..-I
a-
t
\C
......

.
U
CU
Q
1

'"
Q.
CU
en

~
o

.....
\C
N'"
11'\1
11'\
~
......

.....
11'\0

..-I f"l
1 1
11'\11'\
NN

00
......

.....
00'ID
M.....
I 1
Mf"l
'ID \C
, .
00
......

0......
. .....
N.
N
'" .
~~
o .
,Qo-l
Ill......

o-l
\C .....
N
..,00
J~

.......

>.
)!
1
.
,Q
GI
ra.

~
~
....

.
....
....
..-I
III
U

a
CU
o-l
o-l
t

GI
&3
......

o
..-I
o
U
(1::1
=
CU
...
'"
en

.
.., .....
::1M
0.....
101 a-
f-<..-I

c: a
O.c
U
III ...

g ~
o-l .
ra. CU
Cl::
....
o 00
c:
.'"
"" ...
U GI
GI CI.I
.... c:
.... '"
(1::100
c:
Q/(I::I
.c
""....
o
....
0'"
(l
C Q/
o e
......,
'" ...
III III
::IQ.
o-l CU
1IIc:l
&; a

.
.. 0
...U
Q/
Q.U
0'"
o ...
=..,
U
. CU
t:lO:o-l
(1::1
c:l'tl
c:
III
CU.
U III
...t:l
::I
o U
cn,"
....
....
U

.
.
CU
III
Q/
.c
...
C
Q/
...
III
Q.
c:
....
'tI
Q/
'tI
'"
>
o
...
Q.
CU
...
III
.
Q/
00
C
~
III

..
..
..
..
<
,

(
'"
..
..
II'

"
..
..
,
,
1
~
..

it
:?'<i
:;.
c~
!
1