Changes in the trout population of a small Montana stream
by Alfred Henry Wipperman
A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE in Fish and Wildlife Management
Montana State University
© Copyright by Alfred Henry Wipperman (1963)
Abstract:
An investigation of the rainbow, brown, and brook trout population was conducted on Trout Creek,,
Gallatin Counity, Montana from July 1962 to March 1963. The objectives were similar to those of
Holton (1953) who made the initial study of the trout population in this same creek in 1950 arid 1951.
The results from the studies are compared. Four study sections were established at nearly the same
locations as in the initial study.
The distribution of the trout species in the creek was about the same in both studies. A comparison of
physical, chemical, and certain biological factors within sections showed little change between the two
study periods. During the August and October-November inventories, the species composition in the
study sections was 76, 16, and 8 percerit respectively rainbow, brown, and brook trout compared to 78,
3, arid 19 percent for the same species in the initial study. The weight composition was 70, 20, and 10
percent respectively for brown, rainbow, and brook trout compared to 31, 39, arid 30 percent for the
same species in the initial study. The total number of all trout was 22 percent less in the present study,
but total weight was 49 percent greater. The following changes occurred for each trout species from the
initial to the present study: brown trout increased 307 percent in number and 238 percent in weight;
brook trout decreased 65 percent in number arid 50 percent in weight; rainbow trout decreased 23
percent in number and 26 percent in weight. The estimated standing crop in August was 210 pounds
per acre compared to 106 pounds per acre in the initial study. There were 343 trout 7 inches or over in
total length compared to 197 in the initial study. Most of the trout attained a length of 7 inches or over
by their second fall. The average total length in the August inventory was 11.95, 9.55, and 9.30 inches
respectively for brown, brook, and rainbow trout. The average total length for rainbow trout and brook
trout was slightly greater than in -the initial study. CHANGES IN THE TROUT POPULATION OF
A SMALL MONTANA STREAM
by
ALFRED HENRY WIPPERMAN
A t h e s i s s u b m i t t e d t o th e G r a d u a t e F a c u l t y i n p a r t i a l
f u l f i l l m e n t o f t h e r e q u i r e m e n t s f o r th e d e g r e e
of
\
MASTER OF SCIENCE
in
F i s h and W i l d l i f e Management
Approved:
Headj^Major Ddjp^rtment
Chairman, Examining Committee
e an , G r a d u a te D i v i s i o n
MONTANA STATE COLLEGE
Bozeman, Montana
J u n e 1963
iii
Table o f C o n t e n t s
Page
A b s t r a c t ..................................................................................................................................
vi
I n t r o d u c t i o n . . ................................................................................................................
D e s c r i p t i o n of Study A r e a ..............................................................................
R i f f l e a r e a s ..................................... ................................................... .... .
F l a t w a t e r a r e a s .......................................................................................
Pool a r e a s ............................................................
V e l o c i t y and volume ...............................................................................
T em p er at u re s . . . . . . . . .
........................................................
Chemical a n a l y s e s
.......................................................................... \ .
C o v e r ...............................................................................................................
W i l d l i f e ...........................................................................................................
S p e c i e s of f i s h K ........................................................................................
M e t h o d s .................................................................
Population in v e n to rie s .
A g e ...........................
I
Trout P opulations
...........................................................................................................
Species D is tr ib u tio n
........................................................................................
P o p u l a t i o n C h a n g e s ...................
S t a n d i n g P o p u l a t i o n s ..............................................................................
M o v e m e n t ................................................................
R e p r o d u c t io n ...........................................................................................................
I
I
2
2
2
5
5
6
6
7
7
7
7
9
9
10
11
15 .
17
19
Age and Growth . ....................................
20
S u m m a r y ............................................................................................. ...............................
L i t e r a t u r e Cited
.
22
■...........................................................................................................
.2 4
iv
L i s t o f Ta bl es
Page
1.
P h y s i c a l c h a r a c t e r i s t i c s o f s t u d y s e c t i o n s f o r t h e two s tu d y
p e r i o d s ..................................... * . . .... .................................................. ....
4
2.
Chemical a n a l y s i s ( r a n g e s ) f o r t h e two s t u d y p e r i o d s
6
3.
T r o u t numbers and w e i g h t s f o r
each i n v e n t o r y i n S e c t i o n
I . .
10
4.
T r o u t numbers and w e i g h t s f o r
each i n v e n t o r y i n S e c t i o n
2 . .
11
5.
T r o u t numbers and w e i g h t s f o r
each i n v e n t o r y i n S e c t i o n
3 . .
12
6'.
T r o u t numbers and w e i g h t s f o r
each i n v e n t o r y i n S e c t i o n
4 . .
13
7.
Numbers and w e i g h t s o f t r o u t f o r two i n v e n t o r i e s of t h e two
study p erio d s
....................................................................................... * . .
14
Numbers and w e i g h t s from t r o u t 7 i n c h e s or o v er i n t o t a l
l e n g t h f o r th e August i n v e n t o r i e s f o r t h e two s t u d y p e r i o d s .
16
T r o u t marked and r e c o v e r e d i n each s e c t i o n
18
8.
9.
. . . .
. . . . . . . . .
10. T o t a l l e n g t h s o f t r o u t i n each age group i n t h e August i n v e n ­
t o r i e s from th e two s t u d y p e r i o d s ....................... .... ................................
20
V
L i s t of F i g u r e s
Page
I.
T r o u t Creek s t u d y a r e a ( I .
3
IN. , R. 5 E . )
',V t . V ' ‘
•:
'
;
■ :',
v.
.
:
."V:
■* / \
..
Vl
Abstract
An i n v e s t i g a t i o n o f t h e r ai nb o w , brown, and brook t r o u t p o p u l a t i o n
was con ducted on T r o u t Creek,, G a l l a t i n County, Montana from J u l y 1962 t o
March 1963. The o b j e c t i v e s were s i m i l a r t o th o s e o f Holton (1953) who
made t h e i n i t i a l s t u d y o f t h e t r o u t p o p u l a t i o n in t h i s same c r e e k in 1950
arid 1951. The r e s u l t s from th e s t u d i e s a r e compared. Four s tu d y s e c t i o n s
were e s t a b l i s h e d a t n e a r l y t h e same l o c a t i o n s a s i n t h e i n i t i a l s tu d y .
The d i s t r i b u t i o n of th e t r o u t s p e c i e s i n t h e cr ee k was a b o u t t h e same i n both s t u d i e s .
A comparison o f p h y s i c a l , c h e m ic a l, and c e r t a i n b i o l o g i c a l
f a c t o r s w i t h i n s e c t i o n s showed l i t t l e change between t h e two studyperiods.
During th e August and October-November i n v e n t o r i e s , th e s p e c i e s
c o m p o s i ti o n i n t h e s tu d y s e c t i o n s was 76, 16-, and 8 p e r c e r i t r e s p e c t i v e l y
ra in b o w , brown, and brook t r o u t compared t o 78, 3, arid 19 p e r c e r i t f o r t h e
same s p e c i e s i n t h e i n i t i a l s t u d y .
The w e i g h t co m p o si ti o n was 70, 20, and
10 p e r c e n t r e s p e c t i v e l y f o r brown, r a in b o w , and b r o o k ' t r o u t compared t o
31, 39, arid 30 p e r c e r i t f o r t h e same s p e c i e s in th e i n i t i a l s t u d y . The
t o t a l number o f a l l t r o u t was 22 p e r c e n t l e s s i n t h e p r e s e n t s t u d y , b u t
t o t a l w e i g h t was 49 p e r c e r i t g r e a t e r .
The f o l l o w i n g changes o c c u r r e d f o r
each t r o u t s p e c i e s from t h e i n i t i a l t o t h e p r e s e n t s t u d y : brown t r o u t i n ­
c r e a s e d 307 p e r c e n t i n number and 238 p e r c e r i t in w e i g h t ; brook t r o u t de­
c r e a s e d 65 p e r c e n t i n number arid 50 p e r c e n t i n w e i g h t ; ra in b ow t r o u t de­
c r e a s e d 23 p e r c e n t i n number and 26 p e r c e n t in w e i g h t . The e s t i m a t e d
s t a n d i n g crop i n August was 210 pounds p e r a c r e compared t o 106 pounds p e r
a c re in the i n i t i a l study.
There were 343 t r o u t 7 i n c h e s or over in t o t a l
l e n g t h compared t o 197 i n t h e i r i i t i a l s t u d y . Most o f t h e t r o u t a t t a i n e d a
l e n g t h o f 7 i n c h e s o r over by t h e i r second f a l l .
The a v e r a g e t o t a l l e n g t h
i n t h e August i n v e n t o r y was 1 1 . 9 5 , 9 . 5 5 , and 9 .3 0 i n c h e s r e s p e c t i v e l y f o r
brown, br o o k , and rai nb ow t r o u t .
The a v e r a g e t o t a l l e n g t h f o r rainbow
t r o u t and brook t r o u t was s l i g h t l y g r e a t e r th an i n -the i n i t i a l s tu d y .
-1 INTRODUCTION
Holton (.1953) made t h e i n i t i a l i n v e s t i g a t i o n on t h e p o p u l a t i o n and
e c o l o g y o f r ai n bo w , b r o o k , and brown t r o u t i n T r o u t Creek d u r i n g the .
summers and i n t e r v e n i n g w i n t e r o f 1950 and 1951.
He o b t a i n e d i n f o r m a t i o n
on s p e c i e s d i s t r i b u t i o n , movement and p o p u l a t i o n s t a b i l i t y ,
age and gr ow th, s u r v i v a l , and r e p r o d u c t i o n ,
standing crop,
Eleven y e a r s l a t e r ,
the
p r e s e n t i n v e s t i g a t i o n was cond uct ed from J u l y 1962 t h r o u g h March 1963, and
had s i m i l a r o b j e c t i v e s .
I wish t o e x p r e s s a p p r e c i a t i o n t o Dr. C. J . D. Brown who d i r e c t e d t h e
s t u d y and a s s i s t e d i n p r e p a r a t i o n o f th e m a n u s c r i p t .
Thanks a r e due t o
Mr. George Holton who s u g g e s t e d t h e problem and a s s i s t e d i n l o c a t i n g th e
s t u d y s e c t i o n s in t h e f i e l d .
a s s i s t a n c e and enc ou ragement.
I am i n d e b t e d t o my w i f e , E v e l y n , f o r h e r
I am g r a t e f u l to s e v e r a l s t u d e n t s a t Mon­
ta na S t a t e C o l l e g e f o r h e l p i n c o l l e c t i n g f i s h .
The Montana F i s h and Game
Department a l lo w e d use o f sh ock ing equipment and p r e p a r e d t h e s c a l e mounts.
The Montana S t a t e C o l l e g e A g r i c u l t u r a l Expe rim ent S t a t i o n f u r n i s h e d some
equipment and h e l p e d a n a l y z e w a t e r sa mples.
D e s c r i p t i o n o f Study Area
T r o u t Creek i s l o c a t e d a b o u t 4 m i l e s n o r t h e a s t o f B e l g r a d e , Montana.
I t s l e n g t h i s a p p r o x i m a t e l y 4 m i l e s , and i t r u n s t h r o u g h f l a t c u l t i v a t e d
and p a s t u r e la n d b e f o r e emptying i n t o t h e E a s t " G a l l a t i n R i v e r .
s u p p ly comes c h i e f l y from s p r i n g s .
a l s o add t o t h e w a t e r s u p p ly .
I t s w a te r
R u n o f f , p r e c i p i t a t i o n , and i r r i g a t i o n
The d r a i n a g e a r e a i s a b o u t 5 s q u a r e m i l e s .
Th is c r ee k flows t h r o u g h a narrow r a v i n e which has h ig h s t e e p banks (5,t 1 0
f e e t ) leaving very l i t t l e
flood p l a i n .
A d en se growth o f s h r u b s and h e r b s
l i n e th e banks e x c e p t i n t h e mi dd le p o r t i o n where s h r u b s a r e l i m i t e d to
s c a t t e r e d clumps.
The s t u d y a r e a was c o n f i n e d t o t h e upp er 2gr m i l e s o f t h e cr ee k where
f o u r 3 0 0 - f o o t s e c t i o n s were e s t a b l i s h e d .
These were n e a r l y t h e same as
t h o s e of th e i n i t i a l s t u d y ( H olt on 19 5 3 ), and were d e s i g n a t e d I , 2 , 3 ,
4:> b e g i n n i n g u p s tr e a m ( F i g . I ).
and
C e r t a i n p h y s i c a l measurements (Tab le I )
were made a t minimum w a t e r l e v e l s i n each s e c t i o n d u r i n g l a t e J u l y and
e a r l y August.
Average w i d t h s were b as ed on 60 measurements and av er a ge
d e p t h s on s e v e r a l hundred p e r s e c t i o n .
The p e r c e n t a g e o f r i f f l e s ,
flat
w a t e r ( Boussu 195 4) , p o o l s , and bottom t y p e s was t a k e n when d e p t h r e a d i n g s
were made.
R iffle areas.
face tu rb u len ce.
R i f f l e s were c h a r a c t e r i z e d by h ig h v e l o c i t y and s u r ­
They made up a b o u t 44 p e r c e n t o f t h e a r e a w i t h i n th e
s e c t i o n s and t h e i r a v e r a g e d e p t h was 5 . 4 i n c h e s .
The bottom was a b o u t 74
p e r c e n t f i n e g r a v e l , 24 p e r c e n t sand and s i l t , and 2 p e r c e n t har dp an.
F l a t water a r e a s .
F l a t w a t e r was c h a r a c t e r i z e d by d e p t h s l e s s th a n
12 i n c h e s and l a c k e d s u r f a c e t u r b u l e n c e .
29 p e r c e n t of t h e area..
silt,
These c o n s t i t u t e d a p p r o x i m a t e l y
The bottom c o n s i s t e d of a b o u t 62 p e r c e n t sand and
37 p e r c e n t f i n e g r a v e l , and I p e r c e n t hardpan ( a b s e n t i n S e c t i o n s I
and 2 ) .
Pool a r e a s .
P o ol s were c h a r a c t e r i z e d by maximum d e p t h s over 12 i n c h e s
and l i t t l e or no s u r f a c e t u r b u l e n c e .
They made up a p p r o x i m a t e l y 27 p e r c e n t
o f t h e a r e a w i t h i n s e c t i o n s and t h e i r a v e r a g e maximum d e p t h was 2 3 .8
inches.
The bottom was a b o u t 64 p e r c e n t sand and s i l t , 20 p e r c e n t g r a v e l ,
® STUDY SECTION
/ iY t e m p e r a t u r e STATION
1/4 MILE
Fig. I .
T r o u t Creek st u d y a r e a ( I . I N . , R. 5 E . ).
Ta b le L.
P h y s i c a l c h a r a c t e r i s t i c s o f s t u d y s e c t i o n ' s f o r t h e two s t u d y p e r i o d s .
Section
2
I
3
4
Study p e r i o d
Present
In itial
Present
Initial
Present
Initial
Length - f e e t
Average w id th - f e e t
Area - a c r e s
Average d e p t h - i n c h e s
Average v e l o c i t y - f . / s .
Volume - c . f . s .
300
6 .2
0-. 042
5.1
0.55
. , 1.90
-300
5 .5
0.038
0.75
2 .3 6
300
' 10.6
0.07 3
7.9
1.06
7.08
300
1 0 .4
0.07 2
1.75
9.07
300
15.3
0.105
7.7
1.98
13.4 0
306
-300
'300
15.5
15.1
15.5
0.109
0.1 0 4
.0.1 07
8 .3
1.8 2 ■
2.0 0
1.91
12.21
13.82
14.72
R iffles V
Grave!
Sand & s i l t
Hardpan
32
84
13
3
F l a t water I /
Gravel
Sand & s i l t
Hardpan
63
39
61
P o ol s i /
Gravel
Sand & s i l t
Hardpan
5
27
64
9
Figures in percentages
•
22
-
-
-
65
-
34
68
27
5
26
30
70
-
50
-
6
-
13
-
-
40
20
57
23
"
-
44
-
-
.
65
72
27
I
8
14
84
2
33
27
22
75
3
49
-
18,
-
-
—
-
-
Present
In itial
46
72
27
I
• 40
19
64
33
3
21
35
12
59
29
39
—
—
—
—
—
-
-5 and 16 p e r c e n t h ar d p an .
The f o l l o w i n g d i f f e r e n c e s were found between t h e p r e s e n t and i n i t i a l
s t u d i e s ; r i f f l e a r e a i n c r e a s e d a b o u t 32, 10, and 6 p e r c e n t i n S e c t i o n s 3,
I , and 4 r e s p e c t i v e l y , and d e c r e a s e d a p p r o x i m a t e l y 16 p e r c e n t in S e c t i o n
2; f l a t w a t e r i n c r e a s e d a b o u t 20 p e r c e n t i n S e c t i o n 2 and d e c r e a s e d 10
p e rc e n t in S ection 3 with l i t t l e
change i n S e c t i o n s I and 4; pool a r e a de­
c r e a s e d a p p r o x i m a t e l y 22 p e r c e n t in S e c t i o n 3, 8 p e r c e n t i n S e c t i o n I , and
4 p e r c e n t i n b o t h S e c t i o n s 2 and 4.
There was a b o u t 22 p e r c e n t more
r i f f l e a r e a i n a l l s e c t i o n s i n t h e p r e s e n t s t u d y , and a b o u t 26 p e r c e n t
l e s s pool a r e a t h a n i n t h e i n i t i a l s t u d y .
t h e same i n b o th s t u d i e s .
F l a t w a t e r a r e a remained a b o u t
The bottom t y p e s i n t h e p r e s e n t s t u d y were
g e n e r a l l y f i n e g r a v e l p r e d o m i n a t i n g i n r i f f l e a r e a s , and sand and s i l t i n
calm a r e a s .
About t h e same co m p o si ti o n was e s t i m a t e d i n t h e i n i t i a l
study.
V e l o c i t y and volume.
Measurements were made in September (Tab le l )
and were comparable t o th o s e of t h e i n i t i a l s tu d y e x c e p t i n S e c t i o n 2
where t h e v e l o c i t y was a b o u t 40 p e r c e n t le ss,.
Maximum l e v e l s o cc u r r ed in
November when t h e volume i n S e c t i o n I was a b o u t dou ble t h e September flow.
A s ma ll f l o o d caus ed by m e l t i n g snow o c c u r r e d d u r i n g t h e f i r s t week of
F e b r u a r y 1963.
Th is was a b o u t t r i p l e th e September volume.
Water' ( l to
2 c . f . s . ) was d i v e r t e d i n t o an i r r i g a t i o n d i t c h above S e c t i o n 4 d u r in g
the e n t i r e study p e rio d .
Most d i v e r t e d w a t e r r e t u r n e d t o t h e cree k im­
m e d i a t e l y above S e c t i o n 4.
Temperatures.
Water t e m p e r a t u r e s were o b t a i n e d w i t h c o r r e c t e d
maximum-minimum th e rm o m e t e r s .
Three t e m p e r a t u r e s t a t i o n s ( F i g . I ) were
I
-6**
e s t a b l i s h e d a t a b o u t 1t h e same l o c a t i o n s used i n th e i n i t i a l s tu d y .
The
a v e r a g e t e m p e r a t u r e s f o r t h e p r e s e n t ( 4 5 . 2 F . ) and i n i t i a l s t u d y (45.6 F . )
In b o th s t u d i e s , t h e maximum t e m p e r a t u r e was 62 F,
were n e a r l y t h e same.
■(August) and t h e minimum ap pr o ac he d 32 F.
(February).
Weekly maxima were
u s u a l l y 4-15 d e g r e e s h i g h e r than minima.
Numerous s p r i n g s a l o n g Tro ut
Greek p r e v e n t e d i c e f o r m a t i o n even d u r i n g s e v e r a l weeks o f s u b - z e r o
t e m p e r a t u r e s i n J a n u a r y and F e b r u a r y .
■Chemical a n a l y s e s .
Tabl e 2.
Study
periods
Present
In itial
These were made September 9, 1962 ( T ab l e 2 ) .
In
Chemical a n a l y s e s ( r a n g e s ) f o r th e two s tu d y p e r i o d s .
Dissolved
oxygen
(per cent
saturated)
88,-100
77-100
pH
Total
hardness
(
7.9-8.2
7.5 -8 .I
CaCOs)
180-198
222-232
Total
alkalinity
(methyl
o r an g e)
'
168-224
204-223
Conductivity
in
reciprocal
megohms (25° C . )
316-375
450-500
g e n e r a l t h e d i s s o l v e d s a l t c o n t e n t , pH, d i s s o l v e d oxygen, and conduc­
t i v i t y i n c r e a s e d p r o g r e s s i v e l y from S t a t i o n s I to 4.
The d i s s o l v e d s a l t
c o n t e n t and c o n d u c t i v i t y were a b o u t 15-25 p e r c e n t lower th a n r e p o r t e d in
the i n i t i a l study.
D i s s o l v e d oxygen and pH were a b o u t t h e same in both
studies.
C ov er .
Cover and shade were p r o v i d e d by dense gr ow ths o f sedge
( Carex r o s t r a t a ) and clumps o f w ill o w ( S a l i x s p . ) e x c e p t i n S e c t i o n 4
where w il l o w s were a b s e n t .
p e c i a l l y i n S e c t i o n 4.
Undercut banks added c o n s i d e r a b l e co v er , e s ­
A q u a ti c p l a n t s were abun dan t t h r o u g h o u t th e s tu d y
period u n til la t e January.
Most of t h e m id st r ea m v e g e t a t i o n o c c u r r e d i n
-7r i f f l e areas.
W a t e r c r e s s ( N a s t u r t i u m o f f i c i n a l e ) was common a l o n g th e
edges o f t h e s t r e a m i n a l l s e c t i o n s .
I t a l s o o c c u r r e d i n t h e middle as
sm al l p a t c h e s e x c e p t i n S e c t i o n I where i t choked th e s t r e a m from bank t o
bank.
Brook g r a s s ( C a t a b r o s a a q u a t i c a ) was s p a r s e in S e c t i o n s I and 4 and
common i n S e c t i o n s 2 and 3 w h i l e horn ed po olmat ( Z a n n l c h e l l a B a l u s t r I s )
and w a t e r s p ee d w el l ( Ve ronica c o n n a t a ) were s p a r s e in S e c t i o n s I and 2,
a bu nd an t i n S e c t i o n 3, and common i n S e c t i o n 4.
F i l a m e n t o u s a l g a e was
a bu nd an t i n l a t e summer and f a l l , and w i t h o t h e r v e g e t a t i o n formed l a r g e
f l o a t i n g r a f t s a l o n g th e edges o f p o o l s and f l a t a r e a s .
W ildlife.
The k i n g f i s h e r and t h e b l u e heron were t h e o n ly a n im al s
o b s e r v e d known t o p r e y on f i s h .
M us k ra ts and m a l l a r d ducks a l t e r e d th e
h a b i t a t by d e s t r o y i n g most o f th e a q u a t i c v e g e t a t i o n d u r i n g extreme col d
p e r i o d s i n th e w i n t e r .
Muskrats were common t h r o u g h o u t th e s tu d y a r e a and
m a l l a r d ducks were numerous in t h e f a l l and w i n t e r .
S e e c i e s o f f i s h ..
Rainbow t r o u t (SaTmo q a i r d n e r l ) comprised abo ut 75
p e r c e n t o f th e s al m on id p o p u l a t i o n w i t h brown t r o u t ( Salmo t r u t t a ) and
brook t r o u t ( S a l v e l i n u s f o n t i n a l i s ) a c c o u n t i n g f o r a p p r o x i m a t e l y 15 and 10
percent resp ectiv ely .
The m o t t l e d s c u l p i n ( C o t t u s b a i r d i ) was common and
a few sm al l mountain w h i t e f i s h ( Rrosoeium w i l l i a m s o n l ) were c o l l e c t e d in
S e c t i o n 4.
Methods
Population i n v e n t o r i e s .
F i s h were c o l l e c t e d by e l e c t r o f i s h i n g u s i n g
a p o r t a b l e D.C. g e n e r a t o r w i t h a maximum o u t p u t of 900 w a t t s (300 v o l t s
and 3 a m p e r e s ).
The s t u d y s e c t i o n s were d i v i d e d i n t o 1 5 0 - f o o t u n i t s ,
-8 blo c ke d w i t h n e t s , and shocked u n t i l no more f i s h were c a u g h t .
Captured
f i s h were a n e s t h e t i z e d w i t h a I ; 12,000 s o l u t i o n of T r i c a i n e M e t h a n e s u l f o n a t e (MS-222).
T o t a l l e n g t h s were ta k en t o t h e n e a r e s t 0. 1 i n c h and w e i g h t s
t o th e n e a r e s t 0.01 pound.
In c o l l e c t i o n s where t r o u t un d er 3 i n c h e s i n
l e n g t h were nu me rou s, a r e p r e s e n t a t i v e p o r t i o n was measured and th e r e m a in ­
in g were c o u n t e d . ' Weights were a s s i g n e d to t r o u t l e s s t h a n 3 . 6 in c h e s in
l e n g t h s i n c e f i s h t h i s sm al l coul d n o t be weighed i n d i v i d u a l l y .
These a s ­
s ig n e d w e i g h t s were based on a sample of 225 rainbow t r o u t ( 2 . 0 - 3 . 5 i n c h e s )
s e g r e g a t e d i n t o o n e - t e n t h in c h gr o u p s which were c o l l e c t e d o u t s i d e the
study a re a .
T r o u t were marked d i f f e r e n t l y f o r each s e c t i o n by c l i p p i n g
t h e a d i p o s e f i n and c o m b i n a t i o n s o f t h e p e l v i c f i n s .
A f t e r t h e t r o u t were
p r o c e s s e d , t h e y were a l lo w e d t o r e c o v e r i n l i v e boxes and t h e n r e l e a s e d
i n t o th e p o r t i o n of t h e s t r e a m where c a p t u r e d .
Known m o r t a l i t y from sh o ck in g and- h a n d l i n g ac c o u n te d f o r 107 ( 3 . 7
p e r c e n t ) o f 2894 t r o u t c a p t u r e d d u r i n g r e g u l a r i n v e n t o r i e s . ■ A ll c a s u a l t i e s
b u t one were under 4 i n c h e s i n l e n g t h .
Most o f t h e s e (77 p e r c e n t ) were
caus ed by e l e c t r i c s h o c k .
E f f i c i e n c y t e s t s s i m i l a r t o t h o s e of H a s k e ll and Z i l l i o x (1941) were
made to d e t e r m i n e th e c o m p le te n e s s of t h e c o l l e c t i o n s .
Two t e s t s i n v o l v ­
ing 150 f e e t o f s t r e a m i n b o th S e c t i o n s 3 and 4 were con d uc te d d u r in g
regular inventories.
The s i t e s chosen c o n t a i n e d th e d e e p e s t p o o l s (39
i n c h e s ) and a b o u t a v e r a g e a q u a t i c v e g e t a t i o n .
Ten t r o u t o f v a r i o u s s i z e s
. over 4 i n c h e s were c a p t u r e d , marked, and r e t u r n e d to S e c t i o n 4.
Over 150
t r o u t were t a k en in t h e f i n a l c o l l e c t i o n and a l l 10 marked f i s h were r e ­
captured.
A t e s t i n S e c t i o n 3 i n v o l v e d 12 t r o u t over and 13 under 4-. '
inches.
All b u t one marked t r o u t under" 4 i n c h e s were r e c a p t u r e d i n th e
final collection.
Combined r e s u l t s o f t h e two t e s t s showed 1.00 p e r c e n t r e c a p t u r e f o r
t r o u t ov er 4 i n c h e s and 92 p e r c e n t of t h o s e u n d e r 4 i n c h e s .
These d a t a
were th e b a s i s f o r a d j u s t i n g t h e p o p u l a t i o n under- 4 i n c h e s f o r a l l
sections.
Age.
A t o t a l o f 765 s c a l e samples was t a k e n .
Samples were taken
from a i l t r o u t over 4 i n c h e s i n l e n g t h and from a r e p r e s e n t a t i v e sample of
sm aller tr o u t .
Annuli and s c a l e measurements were d e t e r m i n e d w i t h th e a i d
o f a s c a l e p r o j e c t i o n machine.
T r o u t were c r e d i t e d w i t h h a v i n g formed th e
c u r r e n t y e a r ’ s a n n u l i a t t h e time o f c a p t u r e (Brown and Holton 1953) ex­
c e p t f o r c o l l e c t i o n s made i n J a n u a r y and F e b r u a r y 1963.
Brown t r o u t o l d e r
tha n age group I I I co ul d n o t be aged a c c u r a t e l y bec au se e r o s i o n or r e ­
sorption o b lite ra te d scale ch aracters.
These were grouped a s age-IV or '
older.
TROUT POPULATIONS
There was no s t o c k i n g and r e l a t i v e l y l i t t l e
f i s h i n g p r e s s u r e on T r o u t
Creek f o r s e v e r a l y e a r s b e f o r e and d u r i n g th e s tu d y p e r i o d .
i n t h e t r o u t p o p u l a t i o n a r e p r o b a b l y due to o t h e r f a c t o r s .
Any changes
The t r o u t
p o p u l a t i o n s were i n v e n t o r i e d t h r e e ti m es i n each o f t h e f o u r s tu d y
sectio n s as follows:
August 18-25, 1962; Octob er 6-November 2 , 1962;
December 19, 1 9 6 2 - F eb r u ar y 9, 1963.
The minimum time between shocking
p e r i o d s f o r any s e c t i o n was 7 weeks and t h e maximum 15 weeks.
-10Species- D i s t r i b u t i o n
The abundance o f each t r o u t s p e c i e s was d e t e r m in e d by a v e r a g i n g th e
numbers t a ke n d u r i n g a l l i n v e n t o r i e s i n each s e c t i o n .
Rainbow t r o u t were
a bu nd an t th r o u g h o u t th e s t u d y a r e a c o m p ri s in g 44, 77, 83, and 78 p e r c e n t
o f a l l t r o u t i n S e c t i o n s I t o 4 r e s p e c t i v e l y ( Ta b le s 3 - 6 ) .
Tabl e 3.
Brown t r o u t
T r o u t numbers and w e i g h t s f o r each i n v e n t o r y i n S e c t i o n I .
Date o f i n v e n t o r y
■Species
and
age group
Rainbow
0
I
TI
I I I or o l d e r
T o'ta I
Brown
O-III
IV or o l d e r
Total
Brook
0
I
II
I I I or o l d e r
Total
Grand t o t a l
Lbs./acre
i/
Auq. 18. 1962
Wt.
No.
Nov. 2, 1962
No.
Wt.
13
64
-
I
-
14
-
41
14
2
-
57
71
0.04
0.9 7
-
I (l)i/o .2 5
0.23
-
65 ( I )
0.57
1.46
0 .5 1
2 .5 4
2.81
67
-
84 ( 3 3 )
»
1,29
-
-
-
0 .2 7
Dec. 20. 1962
Wt.
No.
1.22
—
-
3 5 (1 0 ) 0.78
25 ( 7 ) 3.91
5 ( 2 ) 1.80
—
65 ( 1 9 ) 6.49
130 ( 2 d) 7.71
:
184
-
84 ( 3 3 )
I
I
50 -(14)
26 ( 1 2 )
5 (3)
N-
81 ( 2 9 )
166 ( 6 2 )
1.29
1. 94
1.9 4
1.14
3.3 4
1.39
—
5 .8 7
9.1 0
217
R ec a p tu r ed f i s h marked p r e v i o u s l y in t h i s s e c t i o n •
were found i n a l l s e c t i o n s b u t w er e n e v e r t h e most a b un d an t s p e c i e s ;.
They
c o n s t i t u t e d 0. 3 , 16 , 13, and 21 p e r c e n t o f a l l t r o u t i n S e c t i o n s I t o 4
respectively.
Brook t r o u t were most a b u n d an t i n th e up per s t u d y s e c t i o n
b u t p r o g r e s s i v e l y d e c r e a s e d downstream.
They comprised 56, 7, 4, and I
-1,1Ta b le 4.
T r o u t humbers and w e ig h t s f o r each- i n v e n t o r y i n S e c t i o n 2.
Date of :i n v e n t o r y
Species
and
age group
No.
1962
Wt.
221
I
I
2
225
1.4 7
. 0 .1 8
0 .4 2
2 .0 2
4.09
43
3
I
4
4
55
21
4
A
u q
.
j.
Oct. 6 . 1962
No.
Wt.
Jan-. 3. 1963
No.
Wt.
176 ( 4 ) 1 / 1.2 2
0 .3 4
2 ( I)
152(54) 1.35
2 ( I ) 0 .4 0
I ( I ) 0 .5 0
I ( I ) 0.76
156(57) 3,01
Rainbow
O
I
TI
I I I or o ld er
Total
Brown
0
I
II
III
IV or o l d e r
Total
Brook
0
.I
II
I I I or o l d e r
Total
Grand t o t a l
L bs./acre •
1/
-
1.18
2 .7 4
0 .5 3
0.42
0.70
5 .6 8
12.61
19 .9 4
23( 12)
I (I)
0..36
0.2 0
4 (4 )
6 (4)
3 4 (2 1 )
5.81
19.62
25.99
0.36
0.41
7 ( 3)
I (I)
0.11
0.05
-
-
-
—
-
-
>—
25
305
-
I (I)
179 ( 6 )
0.77
2 4.80
340
16 ( 9 ) 0.29
3 ( I ) 0.81
3 ( I ) 2.02
2 ( 2 ) 2.2 6
■ 4 (3)11.04
2 8 ( 16 ) 16.42
-
15 ( I )
I
2
»
18 ( I )
—
-
8 (4)
221 (3 1)
0.16
28.89
396
0.3 2
0.15
0.5 0
i—
0.9 7
2 0 2 ( 7 4 ) 2 0 .4 0
279
R ec a p tu r ed f i s h marked p r e v i o u s l y i n t h i s s e c t i o n .
p e rc e n t of a l l t r o u t in S ectio n s I to 4 r e s p e c t i v e l y .
The g e n e r a l d i s t r i ­
b u t i o n of t r o u t i n t h e s t u d y s e c t i o n s i s s i m i l a r t o t h a t r e p o r t e d in th e
i n i t i a l s t u d y ( H olt on 1953).
P o p u l a t i o n Changes
The number and w e i g h t o f each age group were d e t e r m i n e d t o show
changes between each s p e c i e s a t each i n v e n t o r y ( T a b l e s 3 - 6 ) .
There was a
g e n e r a l n u m e r i c a l d e c r e a s e from t h e f i r s t i n v e n t o r y (Au gus t) t o -the l a s t
( D ec e m b e r - F e b r u a r y ) in age groups 0 and I .
Brown t r o u t ( a g e - 0 ) d e c r e a s e d
—12T ab le 5 .
T r o u t -numbers and w e ig h ts f o r each in v e n t o r y i n S e c t i o n 3,
Date o f i n v e n t o r y
Species
and
age group
Rainbow
0
I
II
I I I or o l d e r
Total
Brown
0
I
II
III
IV or o l d e r
Total
Brook
0
I
1I I
I I I or o l d e r
Total
Grand t o t a l
Lbs./acre
l/
Auq,. 25. 1962
No.
Wt.
394
8
4
I
407
.
■
2 .5 4
1 .1 4
1 .3 0
0.66
5.64
Oc t .
No.
' 216 ( 14 ) 1/
5 (2)
1.86
0; 75
0.31
222 ( 17 )
2 .9 2
2 12 ( 8 2 )
14 (6)
8 (5 )
9 (5 )
I'
3 (I)
135(17)
0 .2 5
1.99
5 .78
1.63
4 .7 1
14.36
I (I)
13 (4)
4 (3)
7 ( 6)
4 (2)
2 (2)
30 (17)
0.23
0.84
4.49
4.81
3.70
14.07
18
3
2
0.31
0.34
0 .9 7
10 ( 3 )
2 (2)
12 (5)
264 ( 39.)
0.23
1.62
22.93
218
.
K-
0.49
1.21
3 .3 9
3.74
6.84
15.67
23
491
203 ( 78 )
6 (4 )
3
1.99
0.98
0.7 5
•—
3.72,
41
8
6
3
3
61
-
Dec. 19 . 1962
No.
Wt.
13. 1962
Wt.
-
•
1.03
-
1.26
18.25
174
0 .1 2
0.12
5
252 ( 99 ) 18 .2 0 T
173
5
—
-
-
.
R e c a p tu r e d f i s h marked p r e v i o u s l y i n t h i s s e c t i o n ,
from 1 9 5 ' t o 37, rai n b o w t r o u t from 902 t o 464, and brook t r o u t from 84 to
70.
Rainbow t r o u t ( a g e - l ) d e c r e a s e d from 22 t o 9, brown t r o u t from 17 to
12, w h i l e brook t r o u t i n c r e a s e d from 21 t o 27.
Age grou ps I I or Older
f l u c t u a t e d between i n v e n t o r i e s (August t o D ec em b er - Fe b r u ar y ) f o r a l l
species without d i s t i n c t p a t te r n s .
Brown t r o u t in age g r o u ps I or o l d e r
were r e p o r t e d t o i n c r e a s e d u r i n g th e spawning se ason of t h e i n i t i a l s t u d y .
The t o t a l w e ig h t of t r o u t rema ined a b o u t th e same t h r o u g h o u t the
s t u d y p e r i o d , b u t d i d show some v a r i a t i o n s between i n v e n t o r i e s .
\
Total
—13T able 6.
T ro u t numbers and w e ig h ts f o r each i n v e n t o r y in S e c t i o n 4.
Date of i n v e n t o r y
Species
and
age group
Auq. 18. 1962
■ Wt.
No.
Oct. 27 . 1962."
No.
Mt.
Feb. 9 . 1963
Wt.
No.
Rainbow
O
I
TI
I I I or o l d e r
Total
274
13
I
288
1.9 3
2 .0 0
0 .9 7
4 .9 0
439 ( 9 ) 1/
6 (5 )
—
I (D
44 6(15)
0.9 0
5.44
25 (2)
I
4
3
33 (2)
Brown
O
I
II
III
IV.or older
Total
111
6
6
2
I
126
1.45
1 .3 4
3.95
1 .8 2
3 .9 2
12,48
57( 16)
4 (2)
4 (2 )
2
I
68(20)
1.1 4
1.08
3.3 7
2 .2 2
1.88
9 .6 9
7
I
4
4
.3
19
4
-
0,-07
0.07
17.45
168
Brook
O
I
II
I I I or o l d e r
Total
Grand t o t a l
Lbs./acre
I/
-
4
418
3.61
0.93
I
0.0 3
2
0.99
1.02
3
517(35) 16.15
155
-
(2)
(2 )
(2)
(6)
I
—
—
I
53 (8)
0.1 8
0.36
1.5 2
2 .8 9
4 .9 5
0 .1 5
0 .3 0
2 .8 0
' 4.54
7 .38
15,17
—
0 .2 0
0 .2 0
20.32
195
R e c a p tu r e d f i s h marked p r e v i o u s l y i n t h i s s e c t i o n -
ra in bo w t r o u t w e i g h t was a b o u t 15 p e r c e n t l e s s in t h e October-November and
De cem ber-February i n v e n t o r i e s than i n August.
An i n f l u x of spawning brook
t r o u t i n S e c t i o n I caus ed an o v e r a l l g a i n i n w e ig h t o f a b o u t 61 p e r c e n t
for th is species.
Th is was a l s o o b s er v ed i n th e i n i t i a l s t u d y .
The ,August and October-November i n v e n t o r i e s were used to make co m p ar i­
sons between t h e two s t u d y p e r i o d s b e c a u s e d a t e s of th e i n v e n t o r i e s were
s i m i l a r , and maximum number o f f i s h was c o l l e c t e d a t t h e s e t i m e s ( Ta bl e 7 ) .
The two i n v e n t o r i e s from t h e i n i t i a l s t u d y ( Octobe r-November. 1950, and
-14T ab le 7.
Numbers and w e ig h ts o f t r o u t f o r two i n v e n t o r i e s o f th e two s tu d y
p e rio d s, i /
Species
and
age group
Rainbow
0
I
I I or o l d e r
Total
Brown
0
I
I I or older
Total
Brook
0
I
I I or o l d e r
Total
Grand t o t a l
Lbs./acre
I n i t i a l s tu d y
P r e s e n t s tu d v
Aug. 1951
Aug. 1962
Oct. -Nov. 1962 Qot.- -Nov. 1950
Wt.
Wt.
Wt.
Wt.
No.
No.
No.
No.
902
22
10
934
5 .9 8
3 .3 2
5 .6 0
14.9 0
895
13
4
912
7.6 6
2 .0 2
2 .6 4
12.32
195
17
30
242
2.47
2 .9 7
42.65
48.09
93
9
30
132
1.7 3
2.12
4 5 .9 0
49 .7 5
84
21
4
109
1285
1.31
2.2 1
1. 48
5 .0 0
67.99
210
53
26
9
88
1132
1. 15
3 .96
3 .8 2
8.93
71.00
219
■
1243
66
7
1316
10.06
5.70
2.70
18.46
908
146
18
1072
2.7 8
10.37
5,06
18.22
16
15
10
41
0 .3 7
3 .79
18.37
22.53
44
I
6
51
0 .4 7
0 .1 4
. 5.81
6.42
81
113
2
196
1553
1.9 0
15.18
0.74
17.82
58.81
180
297
69
6
372
1495
2 .6 0
5 .9 0
1.61
10.11
34 .7 4
106
Data from a l l s e c t i o n s combined. Numbers and w e i g h t s a d j u s t e d on th e
b a s i s o f e f f i c i e n c y t e s t s i n b o th s t u d i e s .
August 1951) were t r e a t e d a s i f th e y were from t h e same y e a r .
The s p e c i e s
c o m p o s i ti o n o f t h e p o p u l a t i o n i n ' t h e s t u d y s e c t i o n s was 76, 16, and 8 p e r ­
c e n t r e s p e c t i v e l y r a i n b o w ,, brown, and brook t r o u t compared t o 78, 3, and
19 p e r c e n t f o r t h e same s p e c i e s i n t h e i n i t i a l s t u d y .
The number of brown
t r o u t i n t h e p r e s e n t s t u d y was 307 p e r c e n t g r e a t e r tha n i n t h e i n i t i a l
study.
They i n c r e a s e d 380, 63, and 275 p e r c e n t in age g ro u p s 0, I , and I I
or o ld er r e s p e c t i v e l y .
Brown t r o u t i n age groups I I or o l d e r c o n s t i t u t e d
69 p e r c e n t of a l l f i s h i n t h e s e gr o up s i n t h e p r e s e n t s t u d y , and only 33
p e r c e n t i n t h e i n i t i a l study-.
l e s s than in the i n i t i a l study.
The number o f brook t r o u t was 65 p e r c e n t
They d e c r e a s e d 64 p e r c e n t i n age group 0,
15 74 p e r c e n t i n age group I , b u t i n c r e a s e d 63 p e r c e n t in age grou ps I I or
older.
The number o f ra in bo w t r o u t was 23 p e r c e n t l e s s t h a n i n t h e i n i t i a l
study.
They d e c r e a s e d 16, 83, and 44 p e r c e n t i n age gr o up s 0, I , and TI or
older resp ectiv ely .
Even though t h e r e were more brown t r o u t i n t h e p r e s e n t
s t u d y , t h e t o t a l number o f a l l t r o u t was 22 p e r c e n t l e s s t h a n i n t h e
i n i t i a l s t u d y due to a r e d u c t i o n i n ra in b ow t r o u t and brook t r o u t .
The t o t a l w e i g h t of t r o u t was 49 p e r c e n t g r e a t e r i n t h e p r e s e n t
stud]/.
The w e i g h t c o m p o s i t i o n was 70, 20, and 10 p e r c e n t r e s p e c t i v e l y f o r
brown, rainbow., and brook t r o u t compared t o 31, 39, and 30 p e r c e n t f o r th e
same s p e c i e s . i n t h e i n i t i a l s t u d y .
The w e i g h t of brown t r o u t a g e - I or
o l d e r co m pri se d 64 p e r c e n t o f th e t o t a l w e i g h t in t h e p r e s e n t s t u d y , and
o n ly 30 p e r c e n t i n t h e i n i t i a l s t u d y .
The w e ig h t o f brown t r o u t was 238
p e r c e n t g r e a t e r th an i n t h e i n i t i a l s t u d y , w h i l e brook t r o u t d e c r e a s e d 50
p e r c e n t and ra in bo w t r o u t 26 p e r c e n t .
The d e c r e a s e o f brook t r o u t and ra in b ow t r o u t may be due to an i n ­
c r e a s e of brown t r o u t s i n c e t h e p h y s i c a l , c h e m ic a l, and o t h e r b i o l o g i c a l
c h a r a c t e r i s t i c s changed l i t t l e between t h e two s t u d i e s .
t r o u t may be spawning f i s h from th e E a s t G a l l a t i n R i v e r .
The l a r g e brown
An i n c r e a s e of
l a r g e brown t r o u t was found d u r i n g th e spawning se as on i n t h e i n i t i a l
•study.
Schuck (1945) r e p o r t e d brown t r o u t r e p l a c e d brook t r o u t i n s e v e r a l
New '"York s t r e a m s .
Standing P opulations
The s t a n d i n g p o p u l a t i o n of a l l t r o u t was based on th e August 1962 i n ­
v e n t o r y ( T ab l e 7 ) .
The w e i g h t of t r o u t v a r i e d from 67 pounds p e r a c r e
—
16
—
( S e c t i o n I ) t o 340 pounds ( S e c t i o n 2 ) .
A t o t a l o f I ,285 t r o u t weighing
67 . 9 9 pounds was c o l l e c t e d from a l l s t u d y s e c t i o n s .
Th is i s e q u i v a l e n t to
3, 96 6 t r o u t or 210 pounds p e r a c r e compared t o 4,58 6 t r o u t or 106 pounds
per ac re re p o rte d in the i n i t i a l study.
The g r e a t e s t Weight o f t r o u t
found was 3 9 6 ' pounds p e r a c r e ta k en i n S e c t i o n 2 d u r i n g th e O cto be rNovember i n v e n t o r y .
Th is compares w i t h 337 pounds p e r a c r e ta k e n i n S ec ­
t i o n I a t a comparable i n v e n t o r y i n t h e i n i t i a l s tu d y .
T r o u t 7 i n c h e s or o ve r i n t o t a l l e n g t h comprised a b o u t 6 p e r c e n t of
t h e number and 80 p e r c e n t of th e w e i g h t of a l l t r o u t i n t h e p r e s e n t s tu d y
compared t o 3 p e r c e n t o f th e number and 43 p e r c e n t of t h e w e ig h t in t h e
i n i t i a l study.
There were c o n s i d e r a b l y more brown t r o u t i n t h e p r e s e n t
s t u d y and a bout., eq ua l numbers of ra in b o w t r o u t and brook t r o u t in both
s t u d i e s ( Ta bl e 8 ) . Brown t r o u t made up 55 p e r c e n t of th e number and 81
p e r c e n t of th e w e i g h t i n c o n t r a s t to 16 p e r c e n t of th e number and 40 p e r -
Tabl e 8.
Numbers and w e i g h t s from t r o u t 7 i n c h e s or o v er i n t o t a l l e n g t h
f o r th e August i n v e n t o r i e s f o r t h e two s t u d y p e r i o d s .
S tud y p e r i o d
T o t a l number
Av. t o t a l l e n g t h ( i n c h e s )
T o t a l w e i g h t (pounds)
Average w e i g h t (pounds)
Rainbow
Present I n i t i a l
24
9.1
8.13
0 .3 4
25
8.3
6.37
0.25
c e n t o f t h e w e i g h t in t h e i n i t i a l s t u d y .
S p e c i e s of t r o u t
Brown
Present I n i t i a l
43
12.4
45.20
1.05
7
Tl. 2
5.97
0 .8 5
Brook
Present I n i t i a l
,
Tl
8. 1
2.51
0 .2 3
12
8.3
2.73
0.22
There were 343 t r o u t (7 i n c h e s
o r o v e r ) p e r m i l e of s t r e a m compared to 197 i n th e i n i t i a l s tu d y .
The s t a n d i n g p o p u l a t i o n of 210 pounds o f t r o u t l p e r a c r e ( o n l y s p e c i e s
p r e s e n t e x c e p t f o r c o t t i d s and a few w h i t e f i s h ) found i n T r o u t Greek i s
“ 17much h i g h e r tha n 56 pounds p e r a c r e o f t r o u t r e p o r t e d by S t e f a n i c h (1952)
from a t o t a l f i s h p o p u l a t i o n ( i n c l u d i n g w h i t e f i s h , s u c k e r s , c a r p , and b u r ­
bot.) of 125 pounds p e r a c r e i n P r i c k l e y P ea r Greek, Montana.
Nielson,
Reimers-, and Kennedy (1957) r e p o r t e d a t r o u t p o p u l a t i o n of 120 pounds p e r
a c r e i n C o n v ic t C ree k, C a l i f o r n i a .
McFadden and Cooper (1962) found th e
t r o u t p o p u l a t i o n s i n s i x P e n n s y l v a n i a s t r e a m s v a r i e d from 13 t o 137 pounds
p e r a c r e from t o t a l f i s h p o p u l a t i o n s up t o 354 pounds p e r a c r e .
Movement
A t o t a l o f 1222 t r o u t was marked d u r i n g t h e s tu d y p e r i o d ,
Only t h o s e
t r o u t r e c o v e r e d i n s e c t i o n s where marked a r e t a l l i e d a s r e c a p t u r e s .
Marked
t r o u t were c o n s i d e r e d t o show no movement when r e c a p t u r e d i n t h e s e c t i o n s
where o r i g i n a l l y marked.
The h i g h e s t p e r c e n t a g e ( 4 7 . 6 ) o f marked f i s h r e ­
cove re d was i n S e c t i o n I on November 2, 1962, and th e l o w e s t ( 1 . 7 ) in
S e c t i o n 4 on F e b r u a r y 9, 1963 ( T ab l e 9 ) .
Of t h e t r o u t marked in a l l
s e c t i o n s o f t h e f i r s t i n v e n t o r y ( A u g u s t ) , 2 9 . 6 p e r c e n t were r e c a p t u r e d i n
t h e second i n v e n t o r y ( O ctober-N ovember) and o f t h o s e marked i n th e f i r s t
two i n v e n t o r i e s , 1 9 . 9 , p e r c e n t were r e c a p t u r e d i n th e t h i r d i n v e n t o r y .
( D e c e m b e r - F e b r u a r y ).
Only 13 t r o u t were r e c o v e r e d i n s e c t i o n s o t h e r than
where marked, and 11 o f t h e s e moved between S e c t i o n s 2 and 3.
A small
ra in bo w t r o u t moved a b o u t one m i l e downstream ( from S e c t i o n I t o S e c t i o n
3) and a sm al l brown t r o u t moved a b o u t t h e same d i s t a n c e downstream ( from
Section 2 t o Section 4).
Upstream movement was p r o b a b l y h i n d e r e d by a
sm al l i r r i g a t i o n dam above S e c t i o n 4 s i n c e none of th e t r o u t marked below
t h e dam were found i n u p s tr e a m s e c t i o n s .
—IS—
T a b l e '9.
Section
I
2
3
4
T r o u t marked and r e c o v e r e d i n each sect io n,.
Number
ovaliable
for
recapture
Inventory
date
Number
marked
Aug. 18, 1962
Nov. 2, 1962
Dec. 20, 1962
42
103
-
—
42
145
20
62
Aug.
Oct.
Jan.
'Aug.
Oct.
Dec.
- 92
168
—
92
259
31
74
25,
6,
3,
25,
13,
19,
Aug. 18,
Oct. 27,
Feb.
1962
1962
1963
1962
1962
1962
1962
1962
1963
130
202
158
327
Number
recaptured
_
32.2
48.4
_
i—
-
130
332
>—
158 •
484
39
99
I
Yearlings
or o l d e r
recaptured
(percent)
80.0
58 .8
72 .0
50.0
-
35 .
8
5 0 .0
2 8.6
The r e c o v e r y of marked y e a r l i n g s and o l d e r t r o u t was c o n s i d e r a b l y
h i g h e r f o r th e second i n v e n t o r y from S e c t i o n s 2, 3, and 4 tha n f o r the
t h i r d i n v e n t o r y ( T a b l e - 9) .
The o p p o s i t e was t r u e f o r S e c t i o n I due to an
i n f l u x of m a tu r e brook t r o u t between t h e f i r s t and second i n v e n t o r i e s .
A g r e a t e r p e r c e n t a g e of y e a r l i n g and o l d e r t r o u t was r e c a p t u r e d th a n
in t h e i n i t i a l s t u d y .
Combining a l l s e c t i o n s f o r t h e October-November i n ­
v e n t o r y , t h e marked y e a r l i n g and o l d e r t r o u t c o n s t i t u t e d 5 6 . 2 p e r c e n t of
t h e s e age grou ps i n t h e p r e s e n t s t u d y compared t o 4 1 .8 p e r c e n t in th e
i n i t i a l study.
A h i g h e r p e r c e n t a g e o f marked brown t r o u t was r e c a p t u r e d i n th e s t u d y
s e c t i o n s th an o t h e r t r o u t s p e c i e s .
brown t r o u t .
Th is may i n d i c a t e l e s s movement by .
S t e f a n i c h (1952) found brown t r o u t moved l e s s th a n rainbow
- tr o u t i n P r i c k l e y P ea r Cr eek , Montana.
A t o t a l of 41 .1 p e r c e n t o f 236
-19marked brown t r o u t was r e c a p t u r e d a t l e a s t once in' t h e s t u d y s e c t i o n s ,
■compared t o 3 8 . 7 p e r c e n t o f 150 marked brook t r o u t and 2 5 . 5 p e r c e n t o f 835
marked rai nb ow t r o u t .
R e p r o d u c t io n
The s m a l l e s t s e x u a l l y ma tur e brook t r o u t c o l l e c t e d was 6 . 3 in c h e s i n
length.
Y e a r l i n g s made up 84 p e r c e n t o f m a tu r e t r o u t .
While no s e x u a l l y
m a tu r e y o u n g - o f - y e a r were found, no s p e c i a l s tu d y was made on t h e s e f i s h .
■Holton (1953) found s e v e r a l ma tur e y o u n g - o f - y e a r m a le s i n t h e i n i t i a l
study.
.
B r a s c h , McFadden, and Kmiotek (1958) r e p o r t e d 9 5 . 5 p e r c e n t o f th e
male brook t r o u t in a Wisc on si n s t r e a m were ma ture a t t h e end of t h e i r
f i r s t summer o f l i f e .
The sex o f 30 brook t r o u t c o l l e c t e d on November 2 i n S e c t i o n I was 21
(70 p e r c e n t ) males and 9 (30 p e r c e n t ) f e m a l e s .
found i n t h e i n i t i a l s t u d y .
About t h e same r a t i o was
Brown t r o u t and rainbow t r o u t r a t i o s were n o t
made b ec a u se sex was d e t e r m i n e d on o n ly a few specim ens .
The youngest
m a tu r e brown t r o u t c o l l e c t e d was a y e a r l i n g male.
The spawning se as on f o r brown t r o u t and brook t r o u t l a s t e d through
most of November and e a r l y December.
No c a r e f u l o b s e r v a t i o n s were made
f o r t h e time of f r y emergence, however some brook t r o u t f r y were c o l l e c t e d .
i n s p r i n g a r e a s on March 10, 1963.
Brown t r o u t f r y were p r o b a b l y p r e s e n t
a t t h i s ti m e , b u t none were c o l l e c t e d .
A t o t a l o f 1,181 y o u n g - o f - y e a r t r o u t were p r e s e n t i n a l l s e c t i o n s
d u r i n g th e August i n v e n t o r y ( Ta bl e 7 ) .
Rainbow t r o u t c o n s t i t u t e d 76 p e r ­
c e n t , brown t r o u t 17 p e r c e n t , and brook t r o u t 7 per ce nt, .
There were 5 , 1 9 6
-20y-oong-of-year p e r m i l e o f s tr e a m compared t o 5, 4 6 8 r e p o r t e d i n t h e i n i t i a l
study.
AGE AND GROWTH
T r o h t c o l l e c t e d i n t h e August i n v e n t o r y were used f o r age and growth
estim ates.
Al I s e c t i o n s were combined f o r each t r o u t s p e c i e s bec ause of
t h e sm al l sampie s i z e i n o l d e r age g r oup s ( T a b l e s 7 and 1 0 ) .
Tabl e 10.
Young-of-
T o t a l l e n g t h s o f t r o u t i n each age group i n t h e August i n v e n ­
t o r i e s from t h e two s t u d y p e r i o d s .
Total le n a th s ( inches ) a t caoture
I n i t i a l s tu d v
P r e s e n t s tu d v
Range
Average
Average
Range
No.
Species
and
age group
No.
Brown
0
I
II
III
IV or o l d e r
143
17
13
9
8
3 .1 5
7.61
11.95
14.91
20:28
2 . 4 - 4.1
6 .5 - 9.0
10.4-13.8
13.6-16.7
16.6-24.1
44
I
5
I
Rainbow
0
I
II
III
340
22
■ 6
4
2 . 6-3
7.20
9.30
13.55
1 .3 - 3.9
5 . 8 - 8.9
8.0-11.0
'12.5-15.4
326
142
17
-
2.12
5; 50
8 .6 3
-
1 .0 - 3.3
-3.7- 8 . 3
6 . 5 - 12.6
-
66
21
4
■3.40
6 .4 5
9.5 5
2 . 7- 4 .1
4 . 8 - 7 .7
8.0-10.6
230
66
6
2 .9 0
6.0 8
8 :8 0
• 2 .0 - 4.1
4 . 7 - 9.1
8 . 0- 9 .7
Brook
0
I
II.
y e a r t r o u t were p r e d o m i n a n t f o r each s p e c i e s .
-
-
They made up 96, 80, and 77
p e r c e n t r e s p e c t i v e l y o f r ai nb ow , brown, and brook t r o u t compared to 85, 86,
and 80 p e r c e n t r e s p e c t i v e l y f o r th e same s p e c i e s i n t h e i n i t i a l s tu d y .
There were c o n s i d e r a b l y fewer rainbow t r o u t i n age gr o up s I and I I , and
-21fewer brook t r o u t i n age group I th an i n t h e i n i t i a l s t u d y .
Rainbow t r o u t
o l d e r tha n age group I I I and brook t r o u t o l d e r than I I were n o t found.
The p a u c i t y o f . o l d e r f i s h was a l s o found i n t h e i n i t i a l s t u d y . ' Brown
t r o u t o f a l l age gr ou ps were more numerous th a n in t h e i n i t i a l s tu d y .
Age
groups I or o l d e r made up 60, 95, and 74 p e r c e n t r e s p e c t i v e l y of the t o t a l
ra in b o w , brown., and brook t r o u t w e i g h t s compared t o 85-, 93, and 74 p e r c e n t
f o r th e i n i t i a l s t u d y .
Y o u n g - o f -y e ar brook t r o u t , and brown t r o u t were l o n g e r ( t o t a l l e p g t h )
th a n rai nb ow t r o u t i n th e August i n v e n t o r y (Table 10 ).
Th is d i f f e r e n c e was
p r o b a b l y due t o t h e e a r l i e r h a t c h i n g d a t e s o f brook t r o u t and brown t r o u t .
Brown t r o u t y e a r l i n g s and t w o - y e a r - o l d s grew f a s t e r th an e i t h e r rainbow
t r o u t or brook t r o u t .
The a v e r a g e t o t a l l e n g t h of a l l t r o u t f o r each age group was l a r g e r
th an r e p o r t e d i n t h e i n i t i a l s t u d y ( Table 10 ).
Y o u n g - o f -y e ar rainbow
t r o u t were 0.51 i n c h e s l a r g e r and brook t r o u t were 0 . 5 0 i n c h e s l a r g e r than
in the i n i t i a l study.
The o l d e r age g r oup s o f rainbow t r o u t and brook
t r o u t were a s much a s 1 . 7 in c h e s l a r g e r tha n i n t h e i n i t i a l s t u d y , b u t
t h i s d i f f e r e n c e may be due t o t h e s ma ll sample o f f i s h i n t h e p r e s e n t
study.
The minimum s i z e r a n g e f o r rai n b o w t r o u t i s l a r g e r f o r each age
group i n d i c a t i n g a f a s t e r r a t e of gr ow th.
Growth of brown t r o u t could n o t
be compared b e ca u se d a t a were l a c k i n g i n t h e i n i t i a l s t u d y .
Average c a l c u l a t e d l e n g t h s a t time of an n u l u s f o r m a t i o n was made on
48 brown t r o u t , 37 rai nb ow t r o u t , and 46 brook t r o u t .
s c a l e r a d i u s t o body l e n g t h was assumed.
A c o n s t a n t r a t i o of
-22The t o t a l a v e r a g e c a l c u l a t e d l e n g t h s f o r brown t r o u t a t an n u l u s f o r ­
m a tio n f o r y e a r s I - T I I w er e: 4 . 2 , 9 . 9 , 1 2 .9 i n c h e s .
was r e a c h e d i n t h e second summer.
A le n g th of 7 inches
The s i z e of t r o u t a t a n n u l u s f o r m at io n
c a n n o t be compared w i t h t h e i n i t i a l s t u d y s i n c e o n ly a v e r a g e t o t a l l e n g t h s
were p r e s e n t e d a t th e time o f c a p t u r e i n August.
Growth o f brown t r o u t i n
T r o u t Greek was b e t t e r tha n t h a t in P r i c k l e y P e a r Greek (Bishop 1955) and
a b o u t th e same a s t h a t r e p o r t e d by P u r k e t t (1951) f o r th e West G a l l a t i n
R i v e r , Montana.
The t o t a l a v e r a g e c a l c u l a t e d l e n g t h s f o r rainbow t r o u t a t an nu lu s
f o r m a t i o n f o r y e a r s I - I I I w er e: 3 . 2 , 6 . 8 , 1 1 . 4 i n c h e s .
A l e n g t h of 7
i n c h e s was a c h i e v e d by most o f t h e s e a t th e end of t h e i r second f a l l .
Growth o f ra in b ow t r o u t was a b o u t th e same a s t h a t r e p o r t e d f o r P r i c k l e y
■
P e a r Creek (Bishop 1955) and s lo w er tha n t h o s e from th e West G a l l a t i n
R i v e r , Montana ( P u r k e t t 1951).
The t o t a l a v e r a g e c a l c u l a t e d l e n g t h s f o r brook t r o u t a t a n n u l u s f o r ­
m a tio n f o r y e a r I was 3 . 8 i n c h e s and y e a r I I , 7 . 6 i n c h e s .
Over h a l f of
t h e brook t r o u t a c h i e v e d a l e n g t h o f 7 i n c h e s a t th e end o f t h e second
fall.
The growth of brook t r o u t was s l i g h t l y g r e a t e r tha n t h a t in
P r i c k l e y Pear Creek (Bishop 1955) and s lo w e r than r e p o r t e d f o r th o s e from
t h e West G a l l a t i n R i v e r , Montana ( P u r k e t t 1951)'.
SUMMARY
I.
An i n v e s t i g a t i o n of th e rainbow., brown, and brook t r o u t p o p u l a t i o n
i n T r o u t Cr eek , - G a l l a t i n . County, Montana was con ducted from J u l y 1962 t o
March 1963.
The r e s u l t s were compared w i t h t h e i n i t i a l s t u d y made by
-23H olt on (1953) on t h e same s t r e a m d u r i n g th e summers and i n t e r v e n i n g w i n t e r
o f 1950 and 1951.
2.
A comparison of p h y s i c a l , c h e m i c a l , and c e r t a i n b i o l o g i c a l f a c t o r s
w i t h i n t h e s t u d y s e c t i o n s showed l i t t l e
change between t h e two stu d y
periods.
3.
Brook t r o u t p r e d o m i n a te d i n t h e uppermost s t u d y s e c t i o n , and
ra in bo w t r o u t i n t h e lower t h r e e s e c t i o n s .
4.
During th e August and October-Hovember. i n v e n t o r i e s , t h e s p e c i e s
c o m p o s i ti o n i n th e s t u d y s e c t i o n s was 76, 16, and 8 p e r c e n t r e s p e c t i v e l y
ra in b o w , brown, and brook t r o u t compared t o 78, 3, and 19 p e r c e n t r e ­
s p e c t i v e l y f o r th e same s p e c i e s i n t h e i n i t i a l s tu d y .
-The w e i g h t compo­
s i t i o n was 70, 20, and 10 p e r c e n t r e s p e c t i v e l y f o r brown, r ai n bo w , and
■brook t r o u t compared t o 31, 39, and 30 p e r c e n t r e s p e c t i v e l y f o r th e same
■species in t h e i n i t i a l s t u d y .
5.
The t o t a l number and w e ig h t of brown t r o u t i n c r e a s e d over th e i n ­
i t i a l s t u d y , w h i l e ra in bo w t r o u t and brook t r o u t were l e s s .
The t o t a l
number o f a l l t r o u t was 22 p e r c e n t l e s s , b u t t o t a l w e i g h t was 49 p e r c e n t
g r e a t e r tha n i n t h e i n i t i a l s tu d y .
6'.
The e s t i m a t e d s t a n d i n g crop o f t r o u t in August was 210 pounds p e r
a c r e compared to 106 pounds p e r a c r e i n t h e i n i t i a l s t u d y .
About equal
numbers o f ra in b ow t r o u t and brook t r o u t 7 in c h e s or over i n t o t a l l e n g t h
were p r e s e n t i n b o t h s t u d i e s , b u t t h e r e were 514 p e r c e n t more brown t r o u t
i n th e p r e s e n t s t u d y .
7.
There was e v i d e n c e of l i m i t e d movement.
I n d i c a t i o n s were t h a t
—2 4 brown t r o u t moved l e s s th a n e i t h e r ra in b ow t r o u t or brook t r o u t .
8.
An e s t i m a t e d '5,196 y o u n g - o f - y e a r p e r m i l e o f s tr e a m were p r e s e n t
i n August compared t o 5 , 4 6 8 i n t h e i n i t i a l s t u d y .
9.
Brown t r o u t grew f a s t e r th an e i t h e r brook t r o u t or rai nbo w t r o u t .
The a v e r a g e t o t a l l e n g t h i n th e August i n v e n t o r y f o r age .- II f i s h was 11,95,
9 . 5 5 , and 9 . 3 0 i n c h e s r e s p e c t i v e l y f o r brown, brook# and ra in b ow t r o u t .
The growth o f ra in bo w t r o u t and brook t r o u t was s l i g h t l y f a s t e r tha n in
the i n i t i a l study.
L i t e r a t u r e Cited
B ish op, C l i n t o n G. 1955.
Pear C ree k, Montana.
Age, g ro w th, and c o n d i t i o n o f t r o u t i n lP r i c k l e y
T r a n s . Am. Micro. S o c . , 7 4 ( 2 ) s 134-145.
Boussu, Marvin F.
1954. R e l a t i o n s h i p between t r o u t p o p u l a t i o n s and cover
on a s ma ll stream-. J . W i l d l . Mgmt., 1 8 ( 2 ) ; '229-239.
B r a s c h , John G. , James McFadden., and S t a n l e y Kmiotek. 1958. The E a s t e r n
Brook T r o u t .
I t s L i f e H i s t o r y , Ec ol og y, and Management. P u b l i c a t i o n
226. Wisc ons in C o n s e r v a t i o n D e p t . , Madison I , W i sc o ns i n .
11 pp.
Brown, C. J . D. and George D. H o lt o n .
1953. Time of a n n u l u s f o r m a t io n
on t h e s c a l e s o f brook and ra in b o w t r o u t .
Trans, Am. Micro. S o c . ,
7 2 ( 1 ) : 47- 48 .
H a s k e l l , David C. and R o b e r t G. Z i l l i o x .
1941. F u r t h e r dev elopm ents of
th e e l e c t r i c a l method of c o l l e c t i n g f i s h .
Tr ans . Am. F i s h . S o c . ,
70: 404-409.
H o l t o n , George D. 1953. A t r o u t p o p u l a t i o n s tu d y on a s ma ll cr ee k in
G a l l a t i n County, Montana. J . W i l d l . Mgmt,, 1 7 ( 1 ) : 62- 82 .
McFadden, James T. and Edwin L. Cooper.
1962. An e c o l o g i c a l comparison
o f s i x p o p u l a t i o n s o f brown t r o u t ( Salmo t r u t t a j . T r a n s . Am. F i s h .
S o c . , 9 1 ( 1 ) : 53 -6 2.
N i e l s o n , Reed S . , Norman R e i m e r s , and Harry D. Kennedy.
1957. A s i x - y e a r
s t u d y of th e s u r v i v a l and v i t a l i t y of h a t c h e r y - r e a r e d t r o u t of c a t c h a b l e s i z e i n C o n v ic t Cr eek, C a l i f o r n i a .
CaTif. F i s h and Game, 43:
5- 4 2.
-25P u r k e t t , C h a r l e s A ,, J r ., 1951.
e l e v a t i o n and t e m p e r a t u r e .
Growth r a t e o f t r o u t i n r e l a t i o n to
T r a n s . Am. F i s h . S o c . , 80: 251-259.
S ch u ck , Howard A.
1945. S u r v i v a l , p o p u l a t i o n d e n s i t y , gro wth , and
movement o f t h e w i l d brown t r o u t i n C r y s t a l Creek . T r a n s . Am..
F i s h . S o c . , 73: 209-230;
S t e f a n i c h , Frank A . - 1952. The p o p u l a t i o n and movement o f f i s h i n P r i c k l e y P e a r C ree k, Montana. T r a n s . Am. F i s h . S o c . , 81: 260-274.
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