The fishery of Hyalite Reservoir, Montana, with an evaluation of cutthroat trout reproduction in its
tributaries
by Raymond John Zubik, Jr
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Fish
and Wildlife Management
Montana State University
© Copyright by Raymond John Zubik, Jr (1983)
Abstract:
A summer creel census was conducted to estimate fishing pressure, catch rates and harvest of fish and
to determine if the introduced McBride strain of cutthroat trout were reproducing in the tributaries at
Hyalite Reservoir during 1981 and 1982. Estimated catch rates were 0.28 fish/hour in 1981 and 0.23
fish/hour in 1982. Fishing pressure was estimated to be 19,981 hours in 1981 and 17,733 hours in 1982.
The estimated harvest was 6,064 fish in 1981 and 4,204 fish in 1982. Cutthroat trout contributed 5,862
and 4,032 fish to the harvest in 1981 and 1982, respectively, while less than 200 Arctic grayling and 28
brook trout were harvested in each year of the study. Creeled cutthroat trout averaged 308 mm in total
length and 278 g in 1981 and 317 mm and 322 g in 1982. Spawning by cutthroat trout in both the West
and the East Fork was documented. In the West Fork, upstream movements began in early June and
coincided with increased stream temperatures and flow. Total numbers of cutthroat trout captured first
entering the West Fork in 1981 and 1982 were 236 and 269, respectively. Spawning cutthroat trout
were significantly longer and heavier in 1981 than in 1982. Although heavy angler harvest of spawning
age fish was documented, the age structure of trapped spawners was older in 1982. Successful fry
production was documented in both the East and West Forks during 1981. Cutthroat trout fry averaged
24.5 mm in total length and 99% moved downstream at night. In 1982, an estimated 19,359 cutthroat
trout fry emigrated from the West Fork and a total of 2,878 fry were captured moving downstream in
the East Fork. These downstream movements began in late August and ended in late September during
both years of the study. THE FISHERY OF HYALITE RESERVOIR, MONTANA
WITH AN EVALUATION OF CUTTHROAT TROUT
REPRODUCTION IN ITS TRIBUTARIES
by
Raymond John Zubik, J r .
A t h e s i s s u b m itte d in p a r t i a l f u l f i l l m e n t
of t h e r e q u ir e m e n ts f o r t h e degree
of
Master of S cience
in
F ish and W i l d l i f e Management
MONTANA STATE UNIVERSITY
Bozeman, Montana
August 1983
m a in lib.
N 57%
ii
co p .^
APPROVAL
of a t h e s i s s u b m itte d by
Raymond John Zubikf J r .
This t h e s i s has been r ead by each member of th e t h e s i s
c o m m i t t e e and h a s been fo u n d t o be s a t i s f a c t o r y r e g a r d i n g
c o n t e n t, E nglish usage, fo rm a t, c i t a t i o n s , b ib lio g r a p h ic
s t y l e , and c o n s i s t e n c y , and i s r e a d y f o r s u b m i s s i o n t o t h e
C ollege of Graduate S t u d i e s .
% /3 p / 2 3
Date
~ z < r ; / f s Y U ^ '-X 9
jw .
C h a i r p e r s o n , G r a d u a t e C o m m itte e
Approved f o r th e Major Department
Date
Head, Major Department
Approved f o r t h e C ollege of Graduate S t u d i e s
Date
Graduate Deaif
iii
STATEMENT OF PERMISSION TO USE
In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l l m e n t of t h e
req u irem en ts
for
a m a s te r's
degree
at
M ontana S t a t e
U n i v e r s i t y , I a g r e e t h a t t h e L i b r a r y s h a l l make i t a v a i l a b l e
to
borrow ers
under
the
ru les
of
the
L ib rary .
B rie f
q u o t a t i o n s f ro m t h i s t h e s i s a r e a l l o w a b l e w i t h o u t s p e c i a l
p e r m i s s i o n , p r o v id e d t h a t a c c u r a t e acknowledgment of so u rce
i s made.
P e r m is s i o n f o r e x t e n s i v e q u o t a t i o n from or r e p r o d u c t i o n
o f t h i s t h e s i s may be g r a n t e d by my m a jo r p r o f e s s o r , or i n
h is
absence,
by t h e D i r e c t o r
of L i b r a r i e s when,
in t h e
o p in io n of e i t h e r , th e proposed use of th e m a t e r i a l i s f o r
s c h o la rly purposes.
Any c o p y i n g or use of t h e m a t e r i a l i n
t h i s t h e s i s f o r f i n a n c i a l g a in s h a l l n o t be a llo w e d w i t h o u t
my w r i t t e n p e r m i s s i o n .
Signature
Date ____
V
ACKNOWLEDGMENTS
I w ish
follow ing,
t o e x t e n d my s i n c e r e
ap p rec iatio n
to
who among o t h e r s , a s s i s t e d me through t h e course
of t h i s stu d y .
Dr. W i l l i a m R. Gould 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 in t h e p r e p a r a t i o n of t h e m a n u s c r ip t.
D. P i c t o n
a n d C a l v i n M ..K a y a c r i t i c a l l y
m a n u s c r ip t.
Drs. Harold
review ed th e
The Montana F is h , W i l d l i f e and Parks Department
of Region 3 p r o v id e d needed equipment and a s s i s t a n c e .
Dolan,
the
John
U.S.F.S. D i s t r i c t Ranger, g r a c i o u s l y p r o v id e d housing
and a c c e s s t o t h e r e s e r v o i r
p erio d s.
S pecial
th an k s
is
d u rin g v e h ic u la r
given
to
clo su re
Wayne E d s a l l
who
g r a n t e d a c c e s s t h r o u g h h i s p r o p e r t y t o t h e West Fork o f
H y a l i t e Creek.
S i n c e r e t h a n k s a r e due v o l u n t e e r s , f e l l o w
g r a d u a t e s t u d e n t s and f r i e n d s who a s s i s t e d
in the f i e l d
w ork, o f f e r e d a d v i c e and p r o v i d e d m o r a l s u p p o r t and whose
names a r e
t o o many t o m e n t i o n .
Dr.
D alton B u r k h a l t e r ,
R o b e r t M c F a r la n d , Andy D o l l o f f and G eorge L i k n e s p r o v i d e d
guidance
in
sta tistic a l
com puter
analyses.
program m ing
F in ally ,
and
o p eratio n
and
m ost s i n c e r e t h a n k s a r e
extended t o my w i f e and f a m i l y f o r t h e i r u n d e r s ta n d in g , h e l p
and encouragement th r o u g h o u t my academic c a r e e r .
This s tu d y
was f i n a n c e d by t h e Montana C o o p e r a t i v e F i s h e r y R e s e a r c h
U nit ( C o o p e r a t o r s i
Mont. Dept, of F is h , W i l d l i f e and Parks,
U. S. F i s h and W i l d l i f e S e r v i c e and Mont. S t a t e U n i v .) .
vi
TABLE OF CONTENTS
Page
V I T A ..........................
ACKNOWLEDGMENTS . . . . . . .
iv
..................
. . . . . . . .
LIST OF TABLES ....................................................................................
LIST OF FIGURES
V
V iii
xx
ABSTRACT . ..........................
x ii
INTRODUCTION ...................................
I
DESCRIPTION OF STUDY AREA . ................... . . . . . . . .
3
P h y sica l-C h em ica l C h a r a c t e r i s t i c s . ....................... .
Biota
. . ..........................
A c c e s s i b i l i t y . . . ..........................
METHODS
.................................... . . . . . .
3
8
8
...............................
10
Creel Census ...........................................................................
F is h Trapping . . . . . . . .
.................. . . . . .
Age and Growth . . . . . . . . . . . . . . . . .
S t a t i s t i c a l Analyses
......................................................
10
14
16
16
R E S U L T S .......................................................... .... . ...........................
18
Creel Census . . . . . . . . . . . . . . . . . .
Interview s . . . . . . . .
................................... .
Fishermen C h a r a c t e r i s t i c s . ........................... . . .
Catch R ates . .
. . . . . . . . * * . . ...
F ish Caught and R e l e a s e d ..............................
P a r t y S i z e / T r i p Length . . . . . . . . . . . .
F i s h i n g I n t e n s i t y .............................................................
F i s h in g P r e s s u r e . . . . .
.................................... .
H arv est
. . . . . . . . . . . . . . . . . . .
Spawning F ish . . . . . . . . . .
...............................
S easonal Movements
. .... ..............................................
D iel Movements ............................................
Spawning P o p u la ti o n . . . . ................................... .
S t r a y i n g ........................................................................... .
Spawning Areas in t h e E a s t and West Forks . . .
18
18
18
18
23
24
24
25
30
35
35
38
40
44
45
v ii
TABLE OF CONTENTS (continued)
Page
M o r t a l i t y R a tes of Spawning F ish . . .
Fry
R e c ru itm e n t 1981 . . . . . . . . . . .
R e cru itm en t 1982
R e arin g
^
Age and Growth .................. . . . . . . . .
Back C a l c u l a t e d Lengths a t Age . . . .
Growth o f Tagged F ish ............................... ....
Growth of Known Age F ish . . . . . . .
DISCUSSION
. . . .
. . . .
. . . .
. . . .
. . . .
.................. ....
REFERENCES CITED
APPENDIX
. . . .
46
47.
47
55
57
57
58
59
61
................................................. ....
64
68
v iii
LIST OF TABLES
Table
1.
2.
3.
4.
5.
6.
7.
8.
Page
Ranges and means (in p a r e n t h e s e s ) o f.
s e l e c t e d ch e m ic al and p h y s i c a l p r o p e r t i e s of
H y a l i t e R e s e r v o i r and t h e West and E a s t
Forks of H y a l i t e Creek measured on J u l y 17,
A u g u s t 9, S e p t e m b e r 3 and O c t o b e r I , 1981 . . .
The b e g i n n i n g d a t e s o f s t r a t a d u r i n g t h e
summer c r e e l s u r v e y of 1981 and 1982 . . »
. .
7
11
S e l e c t e d c h a r a c t e r i s t i c s of f is h e r m e n
i n t e r v i e w e d a t H y a l i t e R e s e r v o i r from June September, 1981 and 1982 w i t h p e r c e n t a g e s of
y e a r l y t o t a l s ( i n p a r e n t h e s e s ) ............................. . .
19
E s tim a te d c a t c h r a t e s , in f i s h per hour, f o r
s h o r e and b o a t f i s h e r m e n a t H y a l i t e
R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a from
J u n e - S e p t e m b e r , 1981 w i t h 95 p e r c e n t
c o n fid e n c e i n t e r v a l s (in parentheses)
. . ,
20
E s t i m a t e d c a t c h r a t e s , in f i s h per hour, f o r
s h o r e and b o a t f i s h e r m e n a t H y a l i t e
R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a f ro m
J u n e - S e p t e m b e r , 1982 w i t h 95 p e r c e n t
c o n f id e n c e i n t e r v a l s ( in p a r e n t h e s e s ) . . . . . .
22
E s tim a te d c a t c h r a t e s in f i s h per hour, f o r
s p e c i e s of f i s h h a r v e s t e d from H y a l i t e
R e s e r v o i r , from J u n e - S e p t e m b e r , 1981 and
1982 w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s
(in p a re n th e s e s )
......................................... ....
23
.
Mean p a r t y s i z e and numbers of hours f i s h e d
per perso n (completed t r i p s only) f o r s h o re
and b o at f is h e r m e n a t H y a l i t e R e s e r v o ir from
J u n e - S e p t e m b e r 1981 a n d 1982 w i t h 95
percent
co n fid e n ce
in te rv a ls
(in
parentheses)
. . . . . . .
............................... .
A v e r a g e number o f s h o r e and b o a t f i s h e r m e n
p e r c o u n t d u r i n g s u b s t r a t a and s t r a t a a t
H y a l i t e R e s e r v o i r from J u n e - S e p t e m b e r ,
1981 and 1982
e
24
e
26
ix
LIST OP TABLES (continued)
Table
9.
10.
11.
12.
13.
14.
15.
16.
Page
E s tim a te d number of s h o re and b o at f is h e r m e n
hours a t H y a l i t e R e s e r v o i r d u rin g s u b s t r a t a
and s t r a t a from June - September, 1981 w i t h
95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses) . . . . . . . . . . . .
<i . . .
E s t im a te d number of shore and b o at f is h e r m e n
hours a t H y a l i t e R e s e r v o ir d u rin g s u b s t r a t a
and s t r a t a from June - September, 1982 w i t h
95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses) . . . . o . . . . . . . . . . . .
27
.
29
E s tim a te d numbers of sa lm o n id s h a r v e s t e d by
s h o r e and b o a t f i s h e r m e n a t H y a l i t e
R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a from
J u n e - S e p t e m b e r , 1 9 8 1 w i t h 95 p e r c e n t
co n fid en ce i n t e r v a l s (in p aren th ese s)
. . . . . .
31
E s t im a te d numbers of sa lm o n id s h a r v e s t e d by
s h o r e and b o a t f i s h e r m e n a t H y a l i t e
R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a f ro m
J u n e - S e p t e m b e r , 1982 w i t h 95 p e r c e n t
co n fid en ce i n t e r v a l s (in p aren th ese s)
. . . . . .
32
E s t i m a t e d num bers of f i s h h a r v e s t e d by
s p e c i e s a t H y a l i t e R e s e r v o i r from J u n e S e p t e m b e r , 1981 and 1982 . . . . . . . . . . .
. .
33
The mean l e n g t h s , w e i g h t s and c o n d i t i o n
f a c t o r s (K) f o r c u t t h r o a t t r o u t c r e e l e d a t
H y a l i t e R e s e r v o i r from J u n e - S e p t e m b e r ,
1981 and 1982 w i t h 95 p e r c e n t c o n f i d e n c e
i n t e r v a l s (in p a re n th e s e s ) . . . . . . . . . .
. .
34
Numbers and p e r c e n t ( i n p a r e n t h e s e s ) o f
c u t t h r o a t t r o u t c a p tu r e d moving upstream and
downstream d u rin g d i e l t r a p p i n g of t h e West
F ork o f H y a l i t e C reek i n 1981 . . . . . . . .
. .
39
The age and s e x o f r i p e c u t t h r o a t t r o u t
c a p t u r e d e n t e r i n g t h e W est Fork o f H y a l i t e
C reek d u r i n g 1981 and 1982 . . . . . . . . . .
. .
41
X
LIST OF TABLES (continued)
Table
17.
Page
The mean l e n g t h s , p r e s p a w n i n g w e i g h t s and
c o n d i t i o n f a c t o r s of ag e d m a le and f e m a l e
c u tth ro a t
tro u t
( w ith n u m b e rs in
paren th eses) cap tu red f i r s t e n te rin g the
West Fork o f H y a l i t e C reek d u r i n g 1981 and
.1982 w i t h 95 p e r c e n t c o n f id e n c e i n t e r v a l s of
a l l f i s h i n b r a c k e t s ................................................. .... .
43
18.
Number of days and t e m p e r a t u r e u n i t s between
b e g i n n i n g and peak of s p a w n in g and f r y
e m ig r a tio n f o r c u t t h r o a t t r o u t c a p tu r e d in
t h e West Fork o f H y a l i t e C reek f o r 1981 and
1982 ,. . ............................... ?
■
.......................... 53
19.
The a v e r a g e c a l c u l a t e d t o t a l l e n g t h a t
a n n u l i and a n n u a l i n c r e m e n t s o f g r o w t h f o r
c u t t h r o a t t r o u t of H y a l i t e R e s e r v o i r
c o l l e c t e d f ro m J u n e - S e p t e m b e r , 1982 . . .
20.
21.
22.
23.
24.
. . .
57
The mean t o t a l l e n g t h s w i t h 95 p e r c e n t
c o n f i d e n c e i n t e r v a l s ( i n p a r e n t h e s e s ) and
annual growth in c r e m e n ts of c u t t h r o a t t r o u t
m arked i n 1981 and r e c a p t u r e d i n 1982 ....................
59
The mean l e n g t h o f known age h a t c h e r y and
w i l d c u t t h r o a t t r o u t e x a m in e d a t H y a l i t e
R eservoir
......................................................... . . . . . .
60
The summer f i s h i n g p r e s s u r e s , c a t c h r a t e s ,
numbers h a r v e s t e d and biomass h a r v e s t e d f o r
c u t t h r o a t t r o u t a t H y a l i t e R e s e r v o ir in 1974
and 197 5 and t h e p r e s e n t s t u d y .....................
61
The numbers of c u t t h r o a t t r o u t f r y c a p t u r e d
a t s a m p l i n g s t a t i o n s on t h e West Fork, o f
H y a l i t e Creek from August 26 - September 27,
1982.
Percentages express the r e l a t i o n s h i p
of t h e numbers ta k e n a t t h e subsampled s i t e s
to th e num bers ta k e n a t th e s t a t i o n a r y
s a m p l i n g s i t e ( S t a t i o n I)
..................................... . .
69
The d a t e s and l o c a t i o n o f m arked h a t c h e r y
McBride c u t t h r o a t t r o u t f r y p l a n t s l a t e r
r e c a p t u r e d i n t h e E a s t and West F o r k s of
H y a l i t e C reek ........................................
70
xi
LIST OP FIGURES
F ig u re
1,
Page
Map of t h e stu d y a r e a showing i n l e t s t r e a m s
and o u t f l o w
0
2
,
0
0
9
*
0
0
0
O
0
O
O
O
0 , 0
O
Volume of w ate r s t o r e d in H y a l i t e R e s e r v o ir
from J a n u a r y 1981 t h r o u g h December 1982.
(Data f ro m Montana D ept, o f N at. R e s o u r c e s ,
1983)
O
0
0
*
0
0
0
0
0
0
0
0
0
0
0
0
*
6
9
The mean d a i l y f l o w s and t e m p e r a t u r e s and
numbers of c u t t h r o a t t r o u t c a p tu r e d moving
i n t o t h e West Fork o f H y a l i t e Creek d u r i n g
1981 . . . . . . . . .
0
0
0
0
0
0
0
.
37
The number o f c u t t h r o a t t r o u t f r y c a p t u r e d
i n one d r i f t n e t i n t h e W est and E a s t F o r k s
o f H y a l i t e C r e e k a n d mean d a i l y s t r e a m
t e m p e r a t u r e s from August 17 - September 30,
1981
48
The t o t a l num b e rs o f c u t t h r o a t t r o u t f r y
c a p t u r e d in t h e s t a t i o n a r y , t r a p on t h e West
F o r k o f H y a l i t e C r e e k f r o m A u g u s t 17 S e p te m b e r 30, 1982 w i t h mean d a i l y s t r e a m
tem peratures . . . . . . . . . . . . . . . . .
51
The t o t a l number of c u t t h r o a t t r o u t f r y
c a p t u r e d e m i g r a t i n g f ro m t h e E a s t F ork o f
H y a l i t e Creek from August 17 - September 30,
1982 w i t h mean d a i l y s t r e a m t e m p e r a t u r e s . .
54
0
7.
36
0
The mean d a i l y f l o w s and t e m p e r a t u r e s and
numbers of c u t t h r o a t t r o u t c a p tu r e d moving
i n t o t h e West Fork o f H y a l i t e Creek d u r i n g
1982 . . . . . . . . . . . . . . . . . . . . .
6.
4
O
0
0
0
0
0
0
0
0
0
0
*
0
0
xii
ABSTRACT
A s u m m e r . c r e e l c e n s u s w as c o n d u c t e d t o e s t i m a t e
f i s h i n g p r e s s u r e , c a t c h r a t e s and h a r v e s t o f f i s h and t o
d e t e r m i n e i f t h e i n t r o d u c e d McBride s t r a i n o f c u t t h r o a t
t r o u t w e re r e p r o d u c i n g i n t h e t r i b u t a r i e s a t H y a l i t e
R e s e r v o ir d u r in g 1981 and 1982. E stim a te d c a t c h r a t e s were
0.28 f i s h / h o u r i n 1981 and 0.23 f i s h / h o u r i n 1982. F i s h i n g
p r e s s u r e was e s t i m a t e d t o be 19,981 hours in 1981 and 17,733
hours in 1982. The e s t i m a t e d h a r v e s t was 6,064 f i s h in 1981
and 4,204 f i s h i n 1982. C u t t h r o a t t r o u t c o n t r i b u t e d 5,862
a n d 4 , 0 3 2 f i s h t o t h e h a r v e s t i n 19 81 a n d 19 8 2 ,
r e s p e c t i v e l y , w h i l e l e s s t h a n 200 A r c t i c g r a y l i n g and 28
brook t r o u t were h a r v e s t e d
i n e a c h y e a r of t h e s t u d y .
C r e e le d c u t t h r o a t t r o u t averaged 308 mm in t o t a l le n g t h and
278 g i n 1981 and 317 mm and 322 g i n 1982.
Spaw ning by
c u t t h r o a t t r o u t i n b o t h t h e West and t h e E a s t Fork was
documented.
In t h e West Fork, upstream movements began in
e a r l y June and c o i n c i d e d w i t h i n c r e a s e d str e a m t e m p e r a t u r e s
and flow . T o t a l numbers of c u t t h r o a t t r o u t c a p tu r e d f i r s t
e n t e r i n g t h e West Fork i n 1981 and 1982 w ere 236 and 269,
respectively.
Spawning c u t t h r o a t t r o u t were s i g n i f i c a n t l y
l o n g e r and h e a v i e r i n 1981 t h a n i n 1982. A lt h o u g h h ea v y
a n g l e r h a r v e s t of spawning age f i s h was documented, t h e age
s t r u c t u r e of t r a p p e d s pawners was o l d e r i n 1982. S u c c e s s f u l
f r y p r o d u c t i o n was d o c u m e n te d i n b o t h t h e E a s t and West
Forks d u rin g 1981. C u t t h r o a t t r o u t f r y averaged 24.5 mm in
t o t a l l e n g t h and 99% moved downstream a t n i g h t . In 1982, an
e s t i m a t e d 19,359 c u t t h r o a t t r o u t f r y e m ig ra te d from th e West
F o rk and a t o t a l o f 2 ,8 7 8 f r y w ere c a p t u r e d m oving
d o w n s tr e a m i n t h e E a s t F ork. T h e s e d o w n s tr e a m movements
began i n l a t e A u g u s t :and ended in l a t e September d u r in g both
y e a r s of t h e stu d y .
I
INTRODUCTION
H yalite
R eservoir
has
fish ery for cu tth ro a t tro u t
M ontana f o r
at le a st
bee n
the
site
(Salmo c l a r k i )
a decade.
of
a popular
in s o u th w e s te r n
I n 1974 a n d 1975 t h e
e s t i m a t e d f i s h i n g p r e s s u r e s were about 9,600 and 8,400 hours
(h) and h a r v e s t s a b o u t 2,5 00 and 1,0 00 f i s h , r e s p e c t i v e l y
(Wells,
1976).
From 1953-1973, t h e Montana Department of F is h , W i l d l i f e
and P a r k s
(MDFWP) s u p p o r t e d t h e
p lan ts
Y ellow stone
of
numbers and s i z e s .
Lake
reserv o ir
cu tth ro at
fish ery
tro u t
w ith
in v a rio u s
From 1968-1972 a p p r o x im a te l y 10,000 f i s h
a b o u t 100 m i l l i m e t e r s
(mm) i n t o t a l
r e le a s e d in th e r e s e r v o i r y e a r l y .
le n g th
(TL) w e r e
In 1973, t h e p l a n t was
c h a n g e d t o a p p r o x i m a t e l y 5,0 00 f i s h a b o u t 225 mm TL.
No
p l a n t s w e r e made i n 1974 and 1975 w h i l e t h e s t a t u s of t h e
f i s h e r y was i n v e s t i g a t e d .
D uring 1975,
W ells
(1 9 7 6 )
ev alu ated
th e
n atu ral
re p ro d u c tio n of c u t t h r o a t t r o u t in th e t r i b u t a r i e s of th e
reserv o ir.
H is e v a l u a t i o n
i n d i c a t e d t h e r e w e re no f r y
produced n a t u r a l l y and t h a t t h e f i s h e r y was being s u s t a i n e d
by h a t c h e r y p l a n t s .
T h i s c o n c l u s i o n was a l s o s u p p o r t e d by
t h e s i g n i f i c a n t l y low er h a r v e s t and c a tc h r a t e of c u t t h r o a t
t r o u t i n 1975 due t o t h e a b s e n c e o f p l a n t s i n 1974 and 1975
(Wells,
1976).
2
Upon l e a r n i n g about t h e l a c k of n a t u r a l r e p r o d u c t i o n by
cu tth ro at tro u t,
p e r s o n n e l o f t h e MDFWP r e a s s e s s e d t h e
management s t r a t e g y f o r H y a l i t e R e s e r v o i r ,
As a r e s u l t ,
th e y a t t e m p t e d t o e s t a b l i s h a s e l f - s u s t a i n i n g w i l d c u t t h r o a t
t r o u t p o p u l a t i o n i n H y a l i t e R e s e r v o i r by i n t r o d u c i n g t h e
McBride Lake v a r i e t y of c u t t h r o a t t r o u t .
They c h o s e t h i s
s t r a i n because i t had shown g r e a t e r r e p r o d u c t i v e s u c c e s s and
growth r a t e s th a n t h e Y ellow stone Lake v a r i e t y in mountain
l a k e s w ith p h y s i c a l and chem ical c h a r a c t e r i s t i c s s i m i l i a r to
H y alite Reservoir,
Annually in
J u l y - September of 1976-
1980, a b o u t 2 0,000 McBride Lake c u t t h r o a t t r o u t f r y (25-50
mm TL) were p l a n t e d d i r e c t l y i n t o t h e r e s e r v o i r and an equal
number were p l a n t e d i n t h e West Fork of H y a l i t e Creek,
The
p l a n t s i n t h e c r e e k w e r e an a t t e m p t t o i m p r i n t t h e f i s h t o
t h e s t r e a m and
e s t a b l i s h a s p a w n i n g r u n t h e r e when t h e y
became s e x u a l l y m a t u r e .
Each a n n u a l p l a n t a f t e r 1976 was
s p ra y marked w i t h a d i f f e r e n t c o l o r e d f l u o r e s c e n t pigment t o
i d e n t i f y t h e l o c a t i o n and y e a r of s to c k in g .
This s tu d y
Reservoir to
was c o n d u c t e d on t h e f i s h e r y o f H y a l i t e
(I) measure t h e e x p e c te d i n c r e a s e d p r e s s u r e on
t h e f i s h e r y due t o t h e r a p i d g r o w t h i n t h e p o p u l a t i o n of t h e
G a l l a t i n V a ll e y and (2) e v a l u a t e t h e a t t e m p t t o e s t a b l i s h a
s e l f su s ta in in g w ild c u t th r o a t t r o u t population.
Intensive
f i e l d work was conducted from June through September, 1981
and 1982
3
DESCRIPTION OP STUDY AREA
P h y s ica l-C h em ica l C h a r a c t e r i s t i c s
H y a l i t e R e s e r v o i r i s l o c a t e d in s o u t h w e s te r n Montana in
G a l l a t i n County a p p r o x im a te l y 17»5 a i r k i l o m e t e r s (km) south
o f Bozeman ( F i g u r e I ) .
I t l i e s i n an e l o n g a t e b a s i n i n t h e
G a l l a t i n Range a t an e l e v a t i o n o f 2,012 m e t e r s
d rain s
2,332
h ec tares
(ha)
of
steep
m ountain
(m)
and
slo p es
b elo n g in g t o t h e G a l l a t i n N a t i o n a l F o r e s t and t h e B u r lin g t o n
N orthern R a i l r o a d (Wells, 1976)..
The r e s e r v o i r was c r e a t e d by t h e c o n s t r u c t i o n of a 500
m
l o n g and 34 m h i g h
(M iddle) C r e e k .
earth
fille d
dam a c r o s s
H yalite
Work on t h e dam began i n 1939 b u t b e c a u s e
o f W orld War I I i t was n o t c o m p l e t e d u n t i l F e b r u a r y , 1951
(Wells,
1976).
At maximum c a p a c i t y H y a l i t e R e s e r v o i r c o n t a i n s 991
h e c t a r e - m e t e r s (ha/m) o f w a t e r , h a s a s u r f a c e a r e a of 84.2
ha and a maximum d e p t h of 27 m„
was c r e a t e d t o s u p p l y w a t e r t o
irrig atio n .
O rig in a lly , the re s e rv o ir
th e G a l l a t i n V alley fo r
S i n c e 1957, i t h a s a l s o p r o v i d e d w a t e r t o t h e
C i t y o f Bozeman f o r m u n i c i p a l u s e .
These u s e s and w e a t h e r
p a t t e r n s r e s u l t in t h e r e s e r v o i r t y p i c a l l y being f i l l e d t o
c a p a c i t y i n m i d - J u n e t o l a t e J u l y , drawn down t h r o u g h t h e
deep w ate r o u tf lo w d u r in g t h e r em a in in g summer and f a l l and
th e n m a in ta in e d a t low l e v e l s from October u n t i l t h e o n s e t
4
MONTANA
Hyeilte
Window Roek
Ouerd Ste
I Km
F igure I .
Map o f t h e s t u d y a r e a sh o w in g i n l e t s t r e a m s and
o u tf lo w .
5
of s p r i n g r u n o f f .
Because of t h i s p a t t e r n , t h e r e s e r v o i r i s
s u b j e c t t o v e r t i c a l f l u c t u a t i o n s of up t o 8 m (Wells, 1976),
The volumes of w a te r s t o r e d and p a t t e r n s of f l u c t u a t i o n s in
t h e r e s e r v o i r d u r in g 1981 and 1982 a r e shown in F ig u re 2,
M ost, o f
th e
sp rin g :ru n o ff
appears
to
en ter
the
r e s e r v o i r from t h e E a s t ai|d W est F o r k s o f H y a l i t e C r e e k , .
During 1981, t h e West and E a s t Forks c o n t r i b u t e d an average
d a i l y flow of 0.69
and 0U41
to the r e s e r v o ir .
The s e l e c t e d p h y s i c a l and chem ical c h a r a c t e r i s t i c s of
H y a l i t e R e s e r v o i r and i t s t r i b u t a r i e s m e a s u r e d d u r i n g t h e
summer o f 1981 a r e g i v e n i n T a b l e I .
T h ese m e a s u r e m e n t s
i n d ic a t e t h a t H y a lite R e serv o ir has s u i t a b l e te m p e ra tu re s
and d i s s o l v e d oxygen l e v e l s f q r t r o u t (D.S. ERA, 1976).
tu rb id ities,
specific
conductance,
Low
a l k a l i n i t y and h a r d n e s s
a l l s u g g e s t low b i o l o g i c a l p r o d u c t i v i t y . The t r i b u t a r i e s a r e
c o l d e r and c h e m i c a l l y l e s s e n r i c h e d than t h e r e s e r v o i r .
The
low l e v e l s o f d i s s o l v e d m i n e r a l s , i n t h e r e s e r v o i r and i t s
t r i b u t a r i e s a r e t h e r e s u l t o f t h e d o m in a n c e o f v o l c a n i c
rocks i n t h e w a te rs h e d (Chadwick, 1969).
A l k a l i n i t y , h a r d n e s s and c o n d u c t i v i t y l e v e l s i n t h e
r e s e r v o i r g e n e r a l l y i n c r e a s e d th r o u g h p u t t h e summer.
Marcus
e t a l . (1978) f o u n d t h i s p r o g r e s s i o n a l s o and r e l a t e d i t t o
the
decreasing
im portance
of
surface
run-off
and
the
i n c r e a s i n g im p o rta n c e of ground w a te r c o n t r i b u t i o n s .
Marcus e t a l .
(1978) c l a s s i f i e d H y a l i t e R e s e r v o i r a s
6
1000
1082
1081
HECTARE-METERS
800
800
MONTH
F ig u re 2.
Volume of w ate r s t o r e d in H y a l i t e R e s e r v o ir from
J a n u a r y 1981 t h r o u g h December 1982. (Data from
Montana Dept, of Nat. Resources, 1983).
Table
I.
L o c a tio n
Ranges and means (in p a r e n t h e s e s ) of s e l e c t e d chemical and p h y s ic a l
p r o p e r t i e s of H y a l i t e R e s e r v o i r and t h e West and E a s t F o rk s of
H y a l i t e Creek measured on J u l y 11, August 9, September 3 and October
1981,
Temp(C)
R e s e r v o ir
D epth(m) . I
S u b su rf a c e 1 1 ,0 - 1 6 .0
(14.8)
1 0 ,0 - 1 3 .0
Mid-water
2
(11.9)
8.0-11.5
Bottom
(9.3)
S pecific
D issolved T u rb id ­ conductance
ity
(umhos/cm a t
oxygen
25 C) . pH
(mg/ 1 )
(JTU)
7 . 2 - 8 . 5 2 . 0 — 3 .3
(8 . 1 )
(2 . 1 )
7 . 0 - 9.2 1 . 0 — 2 .7
(8 . 1 )
(1.7)
6 . 0 - 9.3 1 . 5 -2 .7
(7.9)
(2 . 2 )
T o tal
alk.
(mg/ 1 )
Hardness
(mg/ 1 )
60—72 7 . 5 —9.0
(64.3)
60-72 7 . 4 - 8 . 4
(6 8 . 0 )
75-80 7 . 4 - 8 . 4
(75.0)
10-40
(17.5)
5-50
(28.8)
10—40
(27.5)
15-30
(23.8)
15-40
(33.8)
30-50
(37.5)
West Fork
5.5-10.0
(8.3)
0 . 5 —2.5
(1 . 0 )
55-90 7 . 2 - 7 . 7
(70.0)
20-30
(25.0)
20-60
(35.0)
E ast Fork
5.5-9.0
(8.3)
0 . 5 —2.5
(1 . 0 )
55-80 7 . 2 - 8 . 1
(6 8 . 8 )
20-30
(25.0)
20-60
(37.5)
1 S u b su rf a c e = Im below t h e s u r f a c e
2 Bottom = Im above t h e bottom
8
m e s o t r o p h i c b a s e d on c h l o r o p h y l l p r o d u c t i v i t y e s t i m a t e s .
They fo u n d t h e r e s e r v o i r and t r i b u t a r i e s t o be p r i m a r i l y
n itro g en
l i m i t e d and t o be s i m i l i a r t o Quake and Hebgen
L ak e s w h ic h a r e a l s o i n f l u e n c e d by t h e v o l c a n i c r o c k s o f
th is
r e g io n .
B i o ta
C u t t h r o a t t r o u t (Salmo c l a r k i ) was t h e p r e d o m i n a n t
game s p e c i e s
in
H y alite
R eserv o ir.
A rctic
g ray lin g
fThyma l l u s a r c t i c u s ) w e re m o d e r a t e l y a b u n d a n t and s m a l l
numbers of brook t r o u t fS a l v e l i n u s f o n t i n a l i s ) were p r e s e n t .
M ottled s c u lp in
(C o t t u s b a l r d i ) was t h e o n l y o t h e r f i s h
found in t h e r e s e r v o i r .
A d e n s e bloom o f Ap h a n l z o momeHLQn, a b l u e - g r e e n a l g a ,
d e v e l o p e d f ro m e a r l y A u g u st t h r o u g h t h e end o f S e p t e m b e r ,
1981.
This caused t h e Secchi d i s k r e a d in g
to p rogressively
d e c l i n e f ro m 5.4 m i n e a r l y J u l y t o 2.5 m by e a r l y O c to b e r
1981.
A ccessibility
The r e s e r v o i r and i t s a d j a c e n t camping f a c i l i t i e s
are
a v a i l a b l e t o p u b l i c use by a graded but u n s u r fa c e d road from
l a t e May or Ju n e , when t h e road g e n e r a l l y becomes p a s s a b l e ,
t h r o u g h December o r e a r l y J a n u a r y when a c c u m u l a t i n g snows
block a c c e ss.
I t i s a ls o a c c e s s i b l e to w heeled v e h i c le s
9
t h r o u g h o u t t h e w i n t e r i n y e a r s when t h e r o a d i s plow ed t o
f a c i l i t a t e lo g g in g .
Otherwise? a c c e s s i b i l i t y i s l i m i t e d t o
snowmobilefs and s k i e r s .
10
METHODS
Creel Census
A p artia l
creel
census
w as c o n d u c t e d
at
H y alite
R e s e r v o ir from June 13 - September 19, 1981 and from June 7
- September 12, 1982 u s in g a sam pling d esig n m o d if ie d a f t e r
t h e method o f N euhold and Lu (1957).
Each s a m p l i n g s e a s o n
was d i v i d e d i n t o s e v e n 2 - w e e k p e r i o d s c a l l e d s t r a t a w h ich
w e re f u r t h e r s e p a r a t e d i n t o s u b s t r a t a of (I) w eekdays and
(2) w e e k e n d - h o l i d a y s .
Each s u b s t r a t u m of w ee kdays t h e n
c o n s i s t e d o f 10 w eekdays and e a c h s u b s t r a t u m o f w ee k en d h o l i d a y s n o r m a ll y c o n t a in e d 4 days.
The 2 w eekend-holidays
s u b s t r a t a c o n t a i n i n g Independence Day and Labor Day each had
5 days.
The b e g i n n i n g
d a t e s of each s t r a t u m d u rin g th e
s tu d y a r e given in Table 2.
F i f t y p e r c e n t of t h e weekdays and weekend days in each
s u b s t r a t u m were surveyed.
Weekdays t o be sampled w i t h i n a
s u b s t r a tu m were randomly chosen w i t h o u t r e p e t i t i o n w ith t h e
r e s t r i c t i o n t h a t a t l e a s t 2 weekdays per week were censused.
A weekend day from t h e f i r s t weekend of t h e f i r s t s u b s t ra tu m
in
ea ch
season
was
r a n d o m ly
drawn
and
the
subsequent
a l t e r n a t e weekend days were surveyed th ro u g h o u t t h e sampling
p e r io d .
A ll h o l i d a y s were surveyed.
Thus in each s t r a t u m ,
e v e r y day o f t h e week was s a m p l e d a t l e a s t o n c e .
D u r i n g t h e summer o f 1981, f o u r c o u n t s o f f i s h e r m e n
11
Table
2. The b e g i n n i n g d a t e s o f s t r a t a d u r i n g t h e summer
c r e e l survey of 1981 and 1982.
Beginning d a t e
S tra tum
1981
1982
I
Jun 13
Jun 7
II
Jun 27
Jun 21
III
J u l 11
Jul 5
IV
J u l 25
J u l 19
Aug 8
Aug 2
Aug 22
Aug 16
V
VI
VII
Sep 5
. Aug 31
12
w e r e made on e a c h c e n s u s day w h ich c o n s i s t e d o f 15 h.
The
f i r s t count on each day was made a t e i t h e r 0600, 0700, 0800,
o r 0 900 and e a c h o f t h e t h r e e s u b s e q u e n t c o u n t s w e r e made a t
4 h in te rv a ls.
I n 1982,
the
in itia l
count tim es
w e re
c h a n g e d t o 0630, 0730 and 0830 t o b e t t e r c o r r e s p o n d t o t h e
o b s e r v e d f i s h i n g day and a c e n s u s day t h u s c o n s i s t e d o f 14
h.
The number of d a i l y co u n ts were i n c r e a s e d t o f i v e a t 3 h
i n t e r v a l s d u r in g 1982 in an a t t e m p t t o d e c r e a s e t h e v a r i a n c e
found i n t h e 1981 survey.
The
startin g
hour
for
counts
on w e e k d a y s
in
ea ch
s u b s t r a t u m was randomly chosen from t h e i n i t i a l count tim e s .
The
in itia l
counts
on s u b s e q u e n t
w eekdays
w ithin
each
s u b s t r a t u m w e r e a d v a n c e d by I h u n t i l t h e l a t e s t i n i t i a l
c o u n t t i m e was u s e d , a f t e r w h ic h t h e n e x t c o u n t b eg a n a t t h e
earliest
startin g
tim e.
The f i r s t and s u b s e q u e n t c o u n t
t i m e s f o r weekend days were a s s i g n e d in t h e same manner as
f o r w ee k d ay s e x c e p t i n i t i a l c o u n t t i m e s w e r e n o t r a n d o m ly
redrawn f o r each s u b s t r a tu m .
I n i t i a l count t i m e s on t h e two
h o l i d a y s c e n s u s e d w e re r a n d o m l y c h o s e n .
T his procedure
p r o v id e d good coverage of t h e f is h e r m a n day.
The numbers of sh o re f i s h e r m e n and b o a ts w i t h f is h e r m e n
were re c o rd e d s e p a r a t e l y a t t h e t im e of each count.
Counts
w e r e made w i t h t h e a i d of a m o to r v e h i c l e , 7X35 b i n o c u l a r s
and a 20-45 power s p o t t i n g scope.
Counts took l e s s th a n 30
m in u tes t o conduct and were c o n s i d e r e d t o be i n s t a n t a n e o u s
(Neuhold and Lu, 1 957).
13
As many f is h e r m e n as p o s s i b l e were i n t e r v i e w e d between
t h e h o u r s o f t h e i n i t i a l and f i n a l c o u n t s on e a c h c e n s u s
day.
Fisherm en
were
in terv iew ed
f o llo w in g d a ta were c o l l e c t e d ?
in d iv id u ally
and t h e
The s i z e o f t h e f i s h i n g
p a r t y , f i s h i n g mode ( s h o r e o r b o a t ) , t o t a l h o u r s f i s h e d by
each i n d i v i d u a l i n t h e p a r t y , t h e number and s p e c i e s of f i s h
k e p t and r e l e a s e d , t h e r e s i d e n c e and se x o f t h e f i s h e r m e n
and t h e ty p e of b a i t used.
I t was n o t a l w a y s p o s s i b l e t o a c c u r a t e l y c o u n t t h e
number of f i s h e r m e n per b o at d i r e c t l y .
T h e r e f o r e , number of
b o a t f i s h e r m e n i n e a c h c o u n t was e s t i m a t e d by m u l t i p l y i n g
t h e number o f b o a t s i n t h e c o u n t by t h e a v e r a g e number o f
f is h e r m e n per b o a t as d e t e r m in e d from i n t e r v i e w s .
T o t a l f i s h e r m e n hours were c a l c u l a t e d as t h e p roduct of
t h e a v e r a g e number o f f i s h e r m e n p e r c o u n t and t h e t o t a l
p o ssib le
fish in g
hours
in th e
fish in g
d a y w h i c h w as
c o n s i d e r e d t o c o n s i s t of 15 h i n 1981 and 14 h in 1982.
estim ates
of
the
to ta l
number
of
fish
harvested
The
w e re
c a l c u l a t e d as t h e p r o d u c ts of t h e c a tc h r a t e s and f is h e r m e n
ho u rs.
The e s t i m a t e d biomass of a l l s p e c i e s h a r v e s t e d was
d e t e r m i n e d by m u l t i p l y i n g t h e e s t i m a t e d number o f f i s h
h a r v e s t e d by t h e a v e ra g e w eig h t of c r e e l e d f i s h .
During
both
years
of
measured fo r t o t a l le n g th ,
the
study
creeled
fish
w e re
w e i g h e d and e x a m in e d f o r f i n
14
clip s
and t a g s .
analyses.
S cales
w e re t a k e n
for
age and g r o w t h
D u r i n g 1981, a p o r t a b l e u l t r a v i o l e t l i g h t was
used t o i n s p e c t c r e e l e d f i s h f o r f l u o r e s c e n t pigm ents.
P is h Trapping
Traps were i n s t a l l e d t o c a p t u r e a d u l t f i s h e n t e r i n g and
l e a v i n g t h e W est F o rk o f H y a l i t e C reek i n t h e s p r i n g o f 1981
and i n b o t h
t h e West and E a s t F o r k s
i n 1982.
In b o t h
s t r e a m s t r a p s c o n s i s t e d of fyke n e t s and wings c o n s t r u c t e d
o f n y l o n n e t t i n g w i t h a 2.54 c e n t i m e t e r (cm) s q u a r e mesh.
The b a s i c d e s i g n was m o d i f i e d a f t e r Montana D e p a r t m e n t o f
F i s h and Game ( 1979).
Traps were p la c e d a t th e s tr e a m -
r e s e r v o i r i n t e r f a c e when t h e r e s e r v o i r was a t maximum pool
and e n c lo s e d t h e e n t i r e w idth of t h e s trea m .
A f t e r f i s h were f i r s t c a p t u r e d or observed e n t e r i n g t h e
s t r e a m s , t h e t r a p s were o p e r a t e d d a i l y and checked as o f t e n
a s p r a c t i c a l . > The West Fork t r a p was i n o p e r a t i o n from May
4 - J u l y 18, 1981 and from J u n e 10 - J u l y 28, 1982«
The
E ast Fork t r a p was o p e r a t e d from June 25 - August 10, 1982.
F ish c a u g h t in th e t r a p s were i d e n t i f i e d t o s p e c i e s ,
counted,
c l a s s i f i e d by sex and s e x u a l development,
and m e a s u r e d (TL).
weighed
S c a l e s w e r e t a k e n f o r a g e and g r o w t h
a n a l y s e s , e a c h was a f f i x e d w i t h a num bered T - t a g b e h i n d
the
dorsal
movement.
fin
and r e l e a s e d
in
the
d irec tio n
of i t s
A l l c u t t h r o a t t r o u t c a p t u r e d i n 1981 w ere a l s o
examined f o r f l u o r e s c e n t pigment r e t e n t i o n .
15
R e c ta n g u la r d r i f t n e t s 15X61 cm were i n s t a l l e d on J u l y
12 and 13, 1981 i n t h e West and E a s t F o r k s r e s p e c t i v e l y , t o
sam ple th e e m i g r a t i o n of c u t t h r o a t t r o u t f r y ,
No a t t e m p t
was made t o e s t i m a t e t h e t o t a l number o f f r y t h a t moved
d o w n s tr e a m from t h e s e t r i b u t a r i e s t o t h e r e s e r v o i r .
The
n e t s s a m p l e d a b o u t 13 and 17% o f t h e s t r e a m w i d t h o f t h e
West and E a s t F o r k s ,
resp ectiv ely .
t r a p s were c o l l e c t e d t w i c e d a i l y ,
evening.
The c o n t e n t s of t h e
in e a r l y morning and l a t e
F ry w e r e s e p a r a t e d f ro m d e b r i s , i d e n t i f i e d and
counted in t h e f i e l d .
and dea d f r y
Live f r y were r e l e a s e d below t h e t r a p
p re s e rv e d in 10 % fo rm a lin
for
later
to ta l
l e n g t h and w e ig h t measurements.
I n 198 2 , more c o m p l e t e t r a p p i n g of f r y was a t t e m p t e d .
The s t a t i o n a r y t r a p i n s t a l l e d in t h e West Fork covered about
63% o f t h e 5.7 m w id e s t r e a m and was o p e r a t e d f ro m A ugust 25
t h r o u g h S e p t e m b e r 27.
I t was c o n s t r u c t e d w i t h w in g s o f
n y l o n n e t t i n g h a v i n g a 0.7 cm D e l t a mesh a t t a c h e d t o a 0.6
m2 p lyw ood and s c r e e n
(0.7 cm) h o l d i n g box c o n t a i n i n g a
b a f f l e t o c r e a t e s l a c k w a te r.
The rem a ining untrapped 37%
of t h e West Fork was p e r i o d i c a l l y sampled a t f o u r s t a t i o n s
on a t r a n s e c t a c r o s s t h e s t r e a m w i t h a 0.5 m2 t r a p h a v i n g
t h e same mesh s i z e and s c r e e n i n g a s t h e l a r g e r t r a p b u t w i t h
a s m a l l e r h o ld in g box which was m o d if ie d a f t e r t h e design of
P o r t e r (1973).
The E a s t Fork w e i r c o v e r e d t h e e n t i r e 3.5 m w ide s t r e a m
and was o p e r a t e d f ro m S e p t e m b e r 11 t o S e p t e m b e r 27, 1982.
16
Fry were c a p t u r e d w i t h two t r a p s of t h e same d e s ig n and mesh
s i z e a s t h a t u s e d t o s a m p l e t h e f o u r s t a t i o n s on t h e West.
Fork.
A l l h o ld in g boxes were equipped w ith 1.3 cm2 wi r e mesh
s c r e e n a t t h e e n t r a n c e t o p r e v e n t p r e d a t i o n by t r o u t and
scu lp in s.
upstream
d eb ris.
A 2 .5 4 cm mesh w i n g w as p l a c e d a c r o s s a n d
f ro m
the
fry
trap s
to
in tercep t
large
stream
A l l t r a p s w e r e c h e c k e d d a i l y i n t h e e a r l y m o rn in g
w ith c a p t u r e d f r y counted and r e l e a s e d .
Age and Growth
S c a l e s w e re t a k e n from b e t w e e n t h e d o r s a l
fin
and
l a t e r a l l i n e of 20 c u t t h r o a t t r o u t in each 25 mm s i z e group
c o l l e c t e d i n t h e c r e e l a n d / o r s p a w n i n g t r a p s d u r i n g 1982.
S cales
w e re p r e s s e d on s l i d e s
of c e l l u l o s e
a c e t a t e and
examined a t 72X m a g n i f i c a t i o n u s in g a m i c r o f i c h e p r o j e c t o r .
S t a t i s t i c a l Analyses
D ata f ro m c o u n t s and i n t e r v i e w s w ere a n a l y z e d w i t h a
c o m p u te r p r o g ra m d e s i g n e d by Dr. D. E. B u r k h a l t e r of t h e
Montana S t a t e U n i v e r s i t y Computer S cie n ces Department.
The
FIRE I age and g r o w t h p r o g r a m ( H e sse , 1977) was used t o
d e r i v e r e g r e s s i o n l i n e s f o r body l e n g t h a t a n n u lu s f o r m a tio n
and c o r r e l a t i o n c o e f f i c i e n t s , f o r d a t a o b t a i n e d from s c a l e s
u s in g t h e l i n e a r Dahl-Lea., Rosa M. Lee and c o r r e c t e d Rosa M.
17
Lee methods and t h e Monastyrsky l o g a r i t h m i c method of back
calcu latio n .
The l a t t e r
m e th o d was u l t i m a t e l y
because of i t s
h ig h e r c o r r e l a t i o n c o e f f i c i e n t .
chosen
The a c t u a l
back c a l c u l a t i o n s w e r e d e r i v e d f ro m t h e MONASK and AGEMAT
computer programs used by t h e MDFWP F i s h e r i e s D iv is i o n .
C alcu latio n s
of
mean
len g th s,
w eights,
condition
f a c t o r s and age c o m p o s itio n of c u t t h r o a t t r o u t c a p tu r e d were
p e r f o r m e d w i t h t h e SPSS s t a t i s t i c a l p a c k a g e s (Nie e t a l . ,
1975).
A l l c o n f id e n c e i n t e r v a l s and S t u d e n t ’s t s t a t i s t i c s
w e r e c a l c u l a t e d a c c o r d i n g t o t h e m e th o d s o f S n e d e c o r and
C ochran (1967).
sta tistic a l
P v a l u e s w e r e c a l c u l a t e d w i t h t h e MSUSTAT
package
(Lund,
1979)
and
d ifferen ces
c o n s i d e r e d s i g n i f i c a n t a t t h e p.10.050 l e v e l .
w e re
18
RESULTS
Creel Census
Interview s
I n t e r v i e w s w e r e c o n d u c t e d w i t h 1,1 97 a n g l e r s d u r i n g
1981 o f w h ic h 710 w e r e s h o r e and 487 w e re b o a t f i s h e r m e n .
In 1982, a t o t a l of 1,083 a n g l e r s were i n t e r v i e w e d of which
473 w e r e s h o r e a n d 610 w e r e b o a t f i s h e r m e n .
D a t a on
r e s i d e n c y , f i s h i n g g e a r u s e d and s e x o f f i s h e r m e n w ere n o t
c o l l e c t e d from a l l a n g l e r s i n t e r v i e w e d i n 1982.
Fishermen C h a r a c t e r i s t i c s
The r e s i d e n c e , s e x and f i s h i n g g e a r u s e d by f i s h e r m e n
were s i m i l a r d u r in g both y e a r s of t h e s tu d y (Table 3).
Most
o f t h e a n g l e r s a t H y a l i t e R e s e r v o i r w e r e l o c a l m a l e s who
used b a i t .
About 69% o f t h e 1 ,6 8 5 f i s h e r m e n i n t e r v i e w e d
d u r in g 1974 and 1975 were l o c a l a n g l e r s (Wells, 1976).
Catch R a tes
The e s t i m a t e d s e a s o n a l c a t c h r a t e f o r a l l fish e rm e n i n
1981 was s l i g h t l y l e s s t h a n 0.3 f i s h p e r h o u r
The
seasonal catch
r a te for boat
( T a b le 4).
fish e rm e n was about 0.06
f i s h p e r h o u r g r e a t e r t h a n f o r s h o r e f i s h e r m e n (p=0.03 0).
The s e a s o n a l c a t c h r a t e of f is h e r m e n on w ee kend-holidays was
n o t d i f f e r e n t from t h a t of weekday a n g l e r s (p>0.500).
Boat
19
Table 3.
S e l e c t e d c h a r a c t e r i s t i c s of f is h e r m e n i n t e r v i e w e d
a t H y a l i t e R e s e r v o i r from June - September, 1981
and 1982 w i t h p e r c e n t a g e s of y e a r l y t o t a l s ( i n
parentheses).
1961
C haracteristic
Number(%)
!i
*
:•
?
V
1982
Number(%)
: 5
• •
Residence
V
.
Local (<81km from Bozeman)
888(74)
729(77)
S t a t e R e s i d e n t (>81km from Bozeman)
108 (9)
125(13)
N o n re sid e n t
201(17)
92(10)
1,197(100)
946(100)
Total
"
V
■ I
. I
. I
.
Sex
Male
793 ( 6 6 )
721(75)
Female
207(17)
96(10)
J u v e n i l e (u n lic e n s e d )
197(19)
141(15)
1,197(100)
958(100)
T o ta l
;■
■ I
I
..
4
i
■■
F i s h i n g gear
>
B a it*
719(60)
535(53)
A r tif ic ia l lures
222(19)
197(19)
A rtificial flie s
HO (9)
104(10)
Combinations
146(12)
186(18)
1,197(100)
1 , 0 2 2 (10 0 )
T o ta l
I
■
I
.
I
*Worms, c o r n , marshmallows, salmon eggs, e t c .
?
I
ii
I
S
I
v5;
T a b le 4
,
E s t i m a t e d c a t c h r a t e s , i n f i s h p e r h o u r f o r s h o r e and b o a t
f i s h e r m e n a t H y a l i t e R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a from June
- S e p t e m b e r , 1 9 8 1 w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses).
Substrata
Weekdays
Weekend-Holidays
Combined
S tra tum Shore
Boat
T o ta l
Shore
Boat
Total
Shore
Boat
T o ta l
. I
0.00
0.03
0.01
0.00
0.00
0.00
0.00
0.02
0.01
II
0.22
0.52
0.36
0.13
0 =24
0.18
0.16
0.34
0.25
III
0.19
0.37
0.28
0.25
0.35
0.30
0.20
0.38
0.29
IV
0.30
0.28
0.29
0.31
0.36
0.35
0.27
0.33
0.30
V
0.10
0.05
0.08
0.38
0.36
0.37
0.11
0.13
0.12
VI
0.80
0.38
0.73
0.52
0.92
0.62
0.73
0.57
0.67
VII
0.33
0.22
0.32
0.52
0.31
0.45
0.39
0.24
0.36
0.29
(±0.04)
0.24
(±0.05)
0.33
(±0.06)
0.28
(±0.04)
0.26
(±0.03)
0.32
(±0.04)
Season 0.27
t o t a l (±0.04)
0.31
(±0.06)
0.28
(±0.03)
21
f i s h e r m e n c a t c h r a t e s w e r e 0.04 f i s h p e r h o u r g r e a t e r t h a n
s h o r e f i s h e r m e n r a t e s on week d a y s (p=0.235) and 0.09 f i s h
p e r h o u r g r e a t e r on w e e k e n d - h o l i d a y s ( p = 0 .0 1 9 ) .
Seasonal
c a tc h r a t e s were g r e a t e s t in S tra tu m VI f o r a l l c a t e g o r i e s
of f is h e r m e n .
The e s t i m a t e d s e a s o n a l c a t c h r a t e f o r a l l f is h e r m e n in
1982 was s l i g h t l y l e s s t h a n 0.25 f i s h p e r h o u r ( T a b le 5).
The s e a s o n a l c a t c h r a t e f o r b o a t f i s h e r m e n was a b o u t 0.08
f i s h p e r h o u r g r e a t e r t h a n f o r s h o r e f i s h e r m e n ( p = 0 .0 0 3 ) .
S easonal c a t c h r a t e s on w ee kend-holidays were n o t d i f f e r e n t
f ro m w e e k d a y s (p= 0.4 7 7).
Boat f is h e r m e n c a t c h : r a t e s were
0.09 f i s h p e r h o u r g r e a t e r t h a n s h o r e f i s h e r m e n r a t e s on
w eekdays
( p = 0 .0 1 5 )
w eekend-holidays
a n d 0.0 9 f i s h
(p=0.17 8 ) .
per
hour
Seasonal catch
g reater
on
r a t e s w e re
g r e a t e s t in S tra tu m IV f o r a l l c a t e g o r i e s of fish e r m e n .
The e s t i m a t e d s e a s o n a l c a t c h r a t e f o r a l l f is h e r m e n i n
1982
w as a b o u t
( p = 0 .0 1 8 ) .
0 .0 5
Seasonal
fish erm e n , during
fish
per
catch
hour
rates
le ss
for
than
boat
i n 1981
and
shore
w ee kdays and w e e k e n d - h o l i d a y s i n 1982
were s i m i l a r t o r a t e s in 1981.
The s e a s o n a l c a t c h r a t e f o r
1981 was a b o u t 0.08 and 0.16 f i s h p e r h our g r e a t e r t h a n was
fo u n d i n 1974 and 1975, r e s p e c t i v e l y .
The 1982 s e a s o n a l
c a t c h r a t e was a b o u t 0.03 and 0.11 f i s h p e r h o u r g r e a t e r
th a n was found i n 1974 and 1975, r e s p e c t i v e l y (Wells, 1976),
a lth o u g h t h i s s tu d y c o n s i s t e d of seven 2 -week s t r a t a w h i l e
t h e p r e v i o u s s tu d y had s i x 2 -week s t r a t a .
T a b le 5 .
E s t i m a t e d c a t c h r a t e s , i n f i s h p e r h o u r , f o r s h o r e and b o a t
f i s h e r m e n a t H y a l i t e R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a from June
- Septem ber
1 9 8 2 w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses) „
,
Substrata
Weekdays
S tratum Shore
Weekend-Holidays
Combined
Boat
Total
Shore
Boat
T o ta l
Shore
Boat
Total
I
0.11
0.24
0.17
0.05
0.24
0.19
0.10
0.24
0.18
II
0.05
0.33
0.20
0.00
0.16
0.12
0.03
0.23
0.15
III
0.30
0.35
0.33
0.04
0.36
0.29
0.21
0.35
0.31
IV
0.36
0.50
0.41
0.23
0.42
0.31
0.32
0.46
0.37
V
0.06
0.20
0.13
0.11
0.16
0.14
0.07
0.18
0.13
VI
0.23
0.11
0.17
0.36
0.24
0.30
0.30
0.18
0.24
VII
0.20
0.14
0.17
0.00
0.26
0.24
0.20
0.20
0.20
0.29
(±0.05)
0.24
(±0.04)
0.16
(±0.06)
0.25
(±0.05)
0.22
(±0.04)
0.19
(±0.04)
0.27
(±0.04)
0.23
(±0.03)
Season 0.20
t o t a l (±0.05)
23
The c a t c h / r a t e f o r each s p e c i e s shows about 96% of t h e
t o t a l c a tc h r a t e d u r in g each y e a r of t h e stu d y c o n s i s t e d of
c u t t h r o a t t r o u t (Table 6) „
A r c t i c , g r a y l i n g and brook t r o u t
c o n t r i b u t e d l e s s t h a n 4 and 1% t o t h e t o t a l
respectively,
cu tth ro at
(W ells,
Table
catch r a t e ,
A s i m i l a r s i t u a t i o n was seen d u r in g 1974 when
tro u t
com prised
about
94% of
the
catch
rate
1976),
6.
E s tim a te d c a tc h r a t e s in f i s h p er hour f o r
sp e cie s of f i s h h arv ested for H y alite R eservoir,
from
June - S ep tem b er,
1981 and 1982
w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses).
1981
1982
Shore
Boat
Total
Shore
Boat
Total
C utthroat
tro u t
A rctic
grayling
Brook t r o u t
0.2400
0.320
0.2700
0.180
0.260
0.230
0.0100
0.008
0.0100
0.060
0.007
0.006
0.0004
0.000
0.0002
0.004
0.002
0.003
0.27
0.19
(±0.04)(± 0.04)
(±0.03)
T o ta l
0.26
(±0.03)
0.32
0.28
(±0.04) (±0.03)
CSi
O
S p e c ie s
F ish Caught and R e lea sed
About 28 and 24% o f t h e f i s h l a n d e d w e r e r e l e a s e d i n
1981 and 198 2 , r e s p e c t i v e l y .
W ith r e l e a s e d f i s h i n c l u d e d ,
s e a s o n a l c a t c h r a t e s w ould h a v e i n c r e a s e d by 0,11 and 0.08
f i s h p e r h o u r f o r 1981 and 1982, r e s p e c t i v e l y .
Most
fish
w e r e r e l e a s e d b e c a u s e f i s h e r m e n f e l t t h a t t h e y w ere t o o
s m a l l t o kee p a l t h o u g h t h e r e , w e r e no s i z e r e s t r i c t i o n s .
24
Very few i n d i v i d u a l s i n t e r v i e w e d w e r e s t r i c t l y c a t c h and
r e l e a s e f is h e r m e n .
P a r t y S i z e / T r i p Length
The mean p a r t y s i z e s o f b o t h s h o r e and b o a t f i s h e r m e n
were s l i g h t l y over 2.2 p e r s o n s d u r in g each y e a r of t h e study
( T a b le 7 ) .
T h ese a v e r a g e s w e r e a b o u t 0.1 and 0.2 p e r s o n s
l e s s th a n W e lls (1976) found in 1974 and 1975, r e s p e c t i v e l y .
Table
7.
Mean p a r t y s i z e and m ubers of h o u r s f i s h e d p e r
p e r s o n (completed t r i p s only) f o r s h o re and boat
f i s h e r m e n t a t H y a l i t e R e s e r v o i r from J u n e S e p t e m b e r 1981 a n d 1982 w i t h 95 p e r c e n t
c o n f id e n c e i n t e r v a l s (in p a r e n t h e s e s ) .
Mean p a r t y s i z e
Year
Shore
Boat
T o ta l
1981
1982
2.22
2.25
2.32
2.21
2 .26(± 0.09)
2 .23(±0.09)
Mean hours ;f i s h e d / p e r s o n
Shore Boat
2.60
2.84
3.21
3.20
T otal
2.93(±0.15)
3.05(+0.13)
The l e n g t h o f t h e a v e r a g e f i s h i n g t r i p was a b o u t 3.0 h
d u r i n g e a c h y e a r o f t h i s s t u d y ( T a b le 7) w i t h b o a t a n g l e r s
f i s h i n g a b o u t 0.5 h l o n g e r t h a n s h o r e f i s h e r m e n . Both b o a t
and s h o re a n g l e r s f i s h e d about 0.7 h lo n g e r i n 1981 and 1982
th a n in 1974 and 1975 (Wells, 1976).
F i s h in g I n t e n s i t y
D u rin g 1981, t h e a v e r a g e number o f b o a t f i s h e r m e n p e r
count was about 1.3 a n g l e r s g r e a t e r th a n f o r s h o re f is h e r m e n
25
( T a b l e 8).
C o u n ts o f b o a t and s h o r e f i s h e r m e n w e re a b o u t
equal d u r in g weekdays but b o at f is h e r m e n averaged about 4.5
p e r s o n s more on w eekend-holidays.
The a v e r a g e number o f b o a t f i s h e r m e n p e r c o u n t d u r i n g
1982 was a bout 3.6 p e r so n s g r e a t e r th a n f o r s h o re f is h e r m e n .
C o u n ts of b o a t f i s h e r m e n w e r e a b o u t 1.6 and 8.7 p e r s o n s
g r e a t e r t h a n f o r s h o r e f i s h e r m e n on w ee kdays and w ee kendholidays,
respectively.
In 1982, t h e average number of b o at arid s h o r e f is h e r m e n
w ere
about
0.4
more
and
r e s p e c t i v e l y , t h a n i n 1981.
1.9
le ss
people
per
co u n t,
The num bers o f b o a t f i s h e r m e n
on w e e k e n d - h o l i d a y s i n 1982 a p p e a r e d t o be g r e a t e r t h a n i n
1981 w h i l e t h e a v e r a g e number o f s h o r e f i s h e r m e n i n 1982
seemed t o d e c r e a s e on both w eekend-holidays and weekdays.
F i s h in g P r e s s u r e
The s e a s o n a l f i s h i n g p r e s s u r e o f n e a r l y 20,000 h f o r
1981 ( T a b le 9) c o n t a i n e d a b o u t 1,300 more h o u r s by b o a t
f is h e r m e n th a n by
s h o re f is h e r m e n (p=0.108).
T o ta l f i s h i n g
p r e s s u r e was n e a r l y 3,000 h g r e a t e r on w ee k d ay s t h a n on
w eekend-holidays
( p = 0 .0 0 6 ) .
Shore
and
boat
fish in g
p r e s s u r e s were n e a r l y i d e n t i c a l on weekdays b u t b o at f i s h i n g
pressure
exceeded shore p re s s u re
w e e k e n d - h o l i d a y s (p=0.035).
by a b o u t 1 , 4 0 0 h on
P r e s s u r e from b o a t arid s h o r e
f is h e r m e n was g r e a t e s t in S tra tu m I I and I I I ,
and g e n e r a l l y d e c r e a s e d t h e r e a f t e r .
respectively
26
Table
8.
A v e r a g e number o f s h o r e and b o a t f i s h e r m e n p e r
c o u n t d u r i n g s u b s t r a t a and s t r a t a a t H y a l i t e
R e s e r v o i r from June - September 1981 and 1982«,
Substrata
Weekdays
S tratum / Shore
Boat
Weekend-holidays
Shore
Boat
Combined
Shore
Boat
1981
I
II
III
IV
V
VI
VII
2.75
7.15
7.60
6.65
4.15
3.55
6.70
3.39
10.84
11.21
6.68
2.70
1.33
.1=53
7.13
11.06
13.75
8.13
7.13
7.63
5.00
7.19
24.38
15.84
19.19
7.75
5.00
3.38
4.00
8.41
2.73
7.82
2.68
4.43
6.89
4.57
16.48
2.87
9.70
3.75
3.18
2.16
Grand
mean
5.51
5.45
9.12
13.65
6.59
7.91
1982
I
II
III
IV
V
VI
VII
4.00
4.00
3.72
5.60
4.12
3.20
1.88
5.41
6.10
9.19
5.19
6.28
2.59
2.47
11.90
4.70
6.00
8.00
4.10
7.70
5.50
20.70
20.18
18.87
15.03
9.90
14.50
10.28
6.26
4.20
. 4.37
6.29
4.11
4.70
2.91
9.76
10.24
11.99
7.87
7.27
6.41
4.69
Grand
mean
3.81
5.43
6.84
15.55
4.69
8.38
T a b le 9 .
E s t i m a t e d number o f s h o r e and b o a t f i s h e r m e n h o u r s a t H y a l i t e
R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a f r o m J u n e - S e p t e m b e r , 1981
w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n p a r e n t h e s e s ) „
Substrata
Weekdays
S tra tum Shore
Weekend-Holidays
Boat
T o tal
Shore
Boat
Combined
T o ta l
Shore
Boat
T otal
I
413
509
921
428
431
859
841
940
1,781
II
1,072
1,626
2,698
664
1,463
2,127
- 1,736
3,089
4,825
III
1,140
1,681
2,821
825
951
1,776
1,965
2,632
4,597
IV
998
1,002
2,000
488
1,152
1,639
1,486
2,154
3,640
V
623
405
1,028
428
465
893
1,051
870
1,921
VI
533
195
728
458
300
757
991
495
1,486
VII
1,005
230
1,234
300
203
503
1,305
433
1,738
Season 5,782
5,647 11,429
t o t a l (±274) (±1,066) (±436)
3,589
4,964
8,553
9,371 10,611 19,981
(±778) (±1,0 3 0 )(± 1 ,2 9 1 )(± 1 ,1 9 5 )(± 1 ,5 1 3 )(± 1 ,8 8 9 :
28
During t h e 1982 se aso n , t h e t o t a l f i s h i n g p r e s s u r e was
n e a r l y 18,000 h (Table 10).
5,000
h more
(p=0.071).
nearly
fish in g
Boat a n g l e r s c o n t r i b u t e d n e a r l y
pressure
than
shore
fisherm en
T o t a l f i s h i n g p r e s s u r e on w eekend-holidays was
id e n tic al
to
th at
on w ee k d ay s.
Boat fis h e rm e n
p r e s s u r e exceeded s h o re f is h e r m e n p r e s s u r e in t h e weekendh o l i d a y and weekday s u b s t r a t a by a b o u t 3,500 (p<0.001) and
1,500 h (p = 0 .3 4 1 ) ,
shore
fish erm e n
resp ectiv ely .
w as
g reatest
P r e s s u r e f ro m b o a t and
in
S trata
III
and
IV,
r e s p e c t i v e l y and g e n e r a l l y d e c r e a s e d a f t e r t h e s e p e r i o d s .
About 2,0 0 0 f e w e r h o u r s w e r e f i s h e d i n 1982 t h a n 1981
(p = 0 .064).
The c l o s u r e of Hood C reek cam pground f o r t h e
removal of dead t i m b e r may have been r e s p o n s i b l e f o r some of
t h e d e c re a s e d usage in 1982 s i n c e i t c o n t a i n s over o n e - h a l f
of t h e s e r v i c e d camping f a c i l i t i e s l o c a t e d on t h e p e r i p h e r y
of
the
reserv o ir.
affected
by t h i s
S h o re
fish erm en
clo su re.
Shore
seem ed
and b o a t
to
be m o st
fish erm en
p r e s s u r e s were s i m i l a r in 1981 (p=0.108) but s h o re f is h e r m e n
p r e s s u r e was o n l y a b o u t 56% o f t h a t f o r b o a t f i s h e r m e n i n
1982 (p=0.071).
T o ta l p r e s s u r e s
for
w eekend-holidays were
s i m i l a r t o t h o s e on w ee kdays i n b o t h y e a r s o f t h i s s t u d y
in d ic a tin g th a t H y alite R eserv o ir re c e iv e s a s u b s ta n tia l
amount o f f i s h i n g p r e s s u r e on t h e w eekends and h o l i d a y s
s i n c e th e y make up a bout 29% o f t h e a v a i l a b l e f i s h i n g days.
T a b le
IOa
E s t i m a t e d number o f s h o r e and b o a t f i s h e r m e n h o u r s a t H y a l i t e
R e s e r v o i r d u rin g s u b s t r a t a and s t r a t a from June - September, 1982
w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n p a r e n t h e s e s ) .
Substrata
Weekdays
S tratum Shore
Weekend-Holidays
Boat
T o ta l
Shore
Boat
Combined
T o ta l
Shore
Boat
T o ta l
I
560
758
1,318
666
1,159
1,826
1,226
1,917
3,143
II
560
849
1,409
263
1,730
1,393
823
1,979
2,802
III
521
1,286
1,807
336
1,057
1,393
857
2,343
3,200
IV
784
727
1,511
488
842
1,290
1,232
1,569
2,801
V
577
880
1,457
230
554
784
807
1,434
2,241
VI
448
362
810
. 431
812
1,243
879
1,174
2,053
VII
263
346
609
308
576
884
571
922
1,493
Season 3 ,713
t o t a l (±549)
5,208
(±779)
8,920
(±953)
2,682
(±545)
6,130
8,812
6,395 11,337 17,733
(±1,019)(±1,156)(±774) (±1,283)(±1,498)
to
<s
30
The s e a s o n a l f i s h i n g p r e s s u r e s d u rin g both y e a r s were
g en e ra lly
g reatest
from
early
to
m idseason
and th e n
p r o g r e s s i v e l y d e c r e a s e d t h r o u g h o u t t h e summer. T h i s t r e n d
was s i m i l i a r t o t h a t f o u n d by W e l l s (1976).
T otal fis h in g
p r e s s u r e a v e r a g e d a b o u t 6.4 h p e r week p e r s u r f a c e a c r e a t
maximum p o o l d u r i n g t h e s t u d y , a b o u t 178% o f t h a t f o u n d i n
1974 and 1975 (Wells, 1976).
H a rv e st
More th a n 6,000 sa lm o n id s were e s t i m a t e d t o have been
h a r v e s t e d in 1981 (Table 11). Boat f is h e r m e n h a r v e s t e d more
f i s h (58% of t h e t o t a l ) th a n bank f is h e r m e n (p=0.027).
f i s h (57% of t h e t o t a l )
More
were h a r v e s t e d on w ee kend-holidays
t h a n on w ee k d ay s (p=0.039).
About 25% o f t h e t o t a l was
h a r v e s t e d in S tra tu m I I of 1981 which com prised about 14% of
t h e season.
S l i g h t l y over 4,200 f i s h were h a r v e s t e d in 1982 (Table
1 2 ) . More f i s h
fish erm en
than
(75% o f t h e t o t a l )
w ere h a r v e s t e d by b o a t
by s h o r e f i s h e r m e n
(p=0.066).
S im iliar
n u m b e rs o f f i s h w e r e h a r v e s t e d on w e e k e n d - h o l i d a y s and on
w eekdays (p=0.30Q).
About 26% o f t h e t o t a l w e r e h a r v e s t e d
i n S tra tu m IV which com prised ab o u t 14% of t h e season. .
About 1,8 6 0 l e s s f i s h w e r e c a p t u r e d i n 1982 t h a n i n
1981 (p=0.001). Over b o t h s e a s o n s , b o a t a n g l e r s h a r v e s t e d
a b o u t 65% o f a l l f i s h w h i l e 44% w e re h a r v e s t e d on w ee kendholidays.
The 1982 h a r v e s t
was a b o u t 69% o f
the
1981
T a b le 11 „
E s t i m a t e d n u m b e r s o f s a l m o n i d s h a r v e s t e d by s h o r e a n d b o a t
f i s h e r m e n a t H y a l i t e R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a f r o m
J u n e - S e p t e m b e r , 1 9 8 1 w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses).
S ubstrata
Weekdays
S tra tum Shore
Weekend-Holidays
Boat
T o ta l
Shore
Boat
'
T o ta l
Combined
Shore
B oat
Total
I
0
14
14
0
0
0
0
14
14
II
231
850
1,082
85
352
437
316
1,202
1,518
III
217
618
835
203
330
533
420
948
1,368
IV
295
279
574
151
417
568
446
696
1,142
V
55
23
78
162
166
328
217
189
406
VI
4.25
73
498
239
277
516
664
350
1,014
VII
334
51
385
155
63
218
489
114
603
1,908
(±566)
3,465
(±675)
Season 1,557
to tal
(±369)
994
(±324)
1,605
(±451)
2,599
(±556)
2,552
(±491)
3,513
(±724)
6,064
(±875)
T a b le 1 2 .
E s t i m a t e d n u m b e r s o f s a l m o n i d s h a r v e s t e d by s h o r e a nd b o a t
f i s h e r m e n a t H y a l i t e R e s e r v o i r d u r i n g s u b s t r a t a and s t r a t a from
J u n e- S e p t e m b e r , 1 9 8 2 w i t h 95 p e r c e n t c o n f i d e n c e i n t e r v a l s ( i n
parentheses).
S ubstrata
Weekdays
S tra tu m Shore
Weekend-Holidays
Boat
T o ta l
Shore
Boat
Combined
T o ta l
Shore
Boat
T o tal
I
64
183
247
30
273
303
94
456
550
II
26
282
308
0
176
176
26
458
484
III
158
455
612
12
377
389
170
832
±,002
IV
285
363
647
102
353
455
387
716
1,103
V
35
176
211
25
87
112
60
263
323
VI
103
41
144
156
192
347
, 259
233
492
VII
53
49
102
0
149
149
53
198
251
325
(±146)
1,606
(±436)
1,931
(±460)
Season
724
to tal
(±219)
1,548
(±378)
2,272
(±437)
1,049
(±264)
3,514
(±577)
4,204
(±635)
33
harvest
h arv ests
but
still
a b o u t 174
r e p o r t e d by W e l l s
resp ectiv ely .
and 421% g r e a t e r
(1976)
for
than
the
1974 a n d 1 9 7 5 ,
How ever, t h i s s t u d y was two w eeks l o n g e r
each y e a r th a n t h e 1974 and 1975 study.
C u t t h r o a t t r o u t made up a b o u t 97 and 96% o f t h e c r e e l e d
f i s h and were e s t i m a t e d t o com prise about 5,800 and 4,200 of
the f is h
c a u g h t and k e p t i n 1981 and 1982,
( T a b l e 13).
resp ectiv ely
L e s s t h a n 200 A r c t i c g r a y l i n g and 28 b r o o k
t r o u t were e s t i m a t e d t o have been h a r v e s t e d d u r in g 1981 and
1982.
The 1982 c u t t h r o a t t r o u t h a r v e s t was a bout 69% of t h e
1981 h a r v e s t and a b o u t 174 and 528% g r e a t e r t h a n t h e 1974
and 1975 h a r v e s t s , r e s p e c t i v e l y (Wells, 1976).
Table 13.
E s tim a te d numbers of f i s h h a r v e s t e d by S pecies a t
H y a l i t e R e s e r v o i r from June - September, 1981 and
1982.
1982
1981
S p e c ie s
Shore
Boat
Total
Shore
Boat
T o ta l
C utthroat
tro u t
A rctic
grayling
Brook t r o u t
2,430
.3,432
5,862
993
3,039
4,032
119
81
200
38
86
124
3
0
3
18
28
46
Total
2,552
3,513
6,064
1,049
3,154
4,204
The mean l e n g t h of c u t t h r o a t t r o u t h a r v e s t e d i n t h e
1981 c r e e l ( T a b l e 14) was l e s s t h a n i n 1982 (p = 0 .0 0 1 ) ,
The
34
mean w e i g h t s (p>0.500) and c o n d i t i o n f a c t o r s (p=0.118) o f
c u t t h r o a t t r o u t h a r v e s t e d i n 1981 w e re n o t d i f f e r e n t f ro m
t h o s e ta k e n in 1982.
Table 14.
Year
1981
1982
The mean l e n g h t s and c o n d i t i o n f a c t o r s (K) f o r
c u t t h r o a t t r o u t c r e e l e d a t H y a l i t e R e s e r v o i r from
J u n e - S e p t e m b e r , 19.81 and 1982 w i t h 95 p e r c e n t
c o n f id e n c e i n t e r v a l s ( i n p a r e n t h e s e s ) .
Mean
Number length(mm) Number
749
547
308(±4.0)
317(±3.7)
278
287
Mean
w e i g h t (g)
Mean
K
327(±28.4)
322(±16.5)
0.9713(±0.0137)
0.9570(±0.0118)
Marked age I h a t c h e r y c u t t h r o a t t r o u t f i r s t appeared in
the
fis h e rm e n 's
creel
a v e r a g e d 239 mm TL.
in S e p t e m b e r ,
1981;
f i v e of them
T w e n ty - o n e o f t h e s e m a rk e d f i s h w ere
c a p t u r e d by i c e f i s h e r m e n i n December, 1982 a t w hich t i m e
th e y ave ra ged 260 mm TL.
In 198 1 , 278 c u t t h r o a t t r o u t a v e r a g e d 327 g ( T a b le 14)
and s e v e n A r c t i c g r a y l i n g 589 g f o r an e s t i m a t e d b i o m a s s
h a r v e s t of 2,019 kg or 24.0 k g/ha a t maximum pool.
287 c u t t h r o a t t r o u t averaged 322 g (Table 14),
In 1982,
seven A r c t i c
g r a y l i n g 33 9 g and f i v e b r o o k t r o u t 164 g f o r an e s t i m a t e d
b i o m a s s h a r v e s t o f 1,3 4 9 kg o r 16.0 k g / h a a t maximum p o o l .
The co m b in ed a v e r a g e b i o m a s s e s t i m a t e of f i s h h a r v e s t e d
d u r in g t h i s stu d y was about t w i c e t h a t found by W ells (1976)
and a b o u t 8.0 k g / h a l e s s t h a n t h a t f o u n d by Drummond and
Tanner (1960) f o r t h e c u t t h r o a t t r o u t f i s h e r y of t h e 116 ha
T r a p p e r 's Lake in Colorado.
35
Spawning F is h
S easonal Movements
On May 4, 1981 a t r a p was p l a c e d i n t h e West Fork p r i o r
t o any obse rv e d spawning a c t i v i t y i n t h e s tr e a m .
Upstream
movement o f c u t t h r o a t t r o u t b eg a n on May 30, 1981 (3 d ay s
a f t e r t o t a l r e s e r v o i r i c e - o f f ), c o in c id in g w ith in c re a se d
stre a m f lo w s and t e m p e r a t u r e s (Figure 3).
p e a k e d on J u n e 18 and en d e d bn J u l y
d e c re a se d .
Upstream movement
18 a s
stream
flow
Downstream movement ended on J u l y 21 s i g n a l i n g
t h e co m p le tio n of spawning a c t i v i t y .
During 1982, t h e t r a p was n o t i n s t a l l e d u n t i l m i g r a t i n g
c u t t h r o a t t r o u t were observed e n t e r i n g t h e s tr e a m .
Upstream
moving c u t t h r o a t t r o u t w e r e f i r s t o b s e r v e d and t r a p p i n g
begun on June 10 (12 days a f t e r t o t a l r e s e r v o i r i c e - o f f ) ,
s tr e a m flo w s and t e m p e r a t u r e s i n c r e a s e d .
as
Upstream movement
p e a k e d on J u n e 26 and ended on J u l y 24, 1982 a s s t r e a m f l o w s
decreased
(F ig u re 4).
The l a s t
c a p t u r e d on J u l y 28, 1982.
d o w n s tr e a m m i g r a n t was
The 1982 s p a w n i n g s e a s o n t h u s
began 11 days and ended 7 days l a t e r than i n 1981.
C u tth ro at tr o u t ap p aren tly
use te m p e r a tu r e s a n d /o r
f lo w s a s cues f o r spawning movements.
Wells (1976) r e p o r t e d
t h a t c u t t h r o a t t r o u t f i r s t e n t e r e d t h e West Fork as str e a m
36
Num bers
FIow(Ms)
Mean s t r e a m temp(C)
K
/\
i \
I \
i
'- U
i\
I I IV
V
Ju n e
F ig u re 3.
U
20
\/v,AT—\
V v \ A
*0
10
July
The mean d a i l y f lo w s and t e m p e r a t u r e s and numbers
of c u t t h r o a t t r o u t c a p tu r e d moving i n t o t h e West
Fork of H y a l i t e Creek d u rin g 1981.
37
Mean s t r e a m temp(C)
—
Fl ow
----- T e m p e r a t u r e
----- C u t t h r o a t t r o u t
XJ
June
F ig u re 4.
julY
The mean d a i l y f lo w s and t e m p e r a t u r e s and numbers
of c u t t h r o a t t r o u t c a p t u r e d moving i n t o th e West
f o r k of H y a l i t e Creek d u rin g 1982.
38
f l o w i n c r e a s e d and when t h e mean d a i l y s t r e a m t e m p e r a t u r e
was a b o u t 3 C.
S n y d er and T a n n e r ( I 9 6 0 ) , and Lund (1974)
r e p o r t e d i n c r e a s e d upstream movement by c u t t h r o a t t r o u t as
stream flow s in c re a se d .
Jones e t a l.
(1982) a l s o fo u n d
r a p i d i n c r e a s e s in t h e number of upstream moving c u t t h r o a t
t r o u t f ro m Y e l l o w s t o n e Lake c o i n c i d i n g w i t h
in creasin g
t e m p e r a t u r e s which, however, o c c u r r e d w ith d e c r e a s i n g flow.
D iel Movements
D uring th e
spaw ning r u n s ,
u p stream
m ovem ents of
c u t t h r o a t t r o u t were i n h i b i t e d by s h a r p l y low er d a i l y str e a m
t e m p e r a t u r e s and a c c e l e r a t e d by s h a r p l y h ig h e r te m p e r a t u r e s
a s was f o u n d by Lund (1974).
When s t r e a m
tem peratures
a p p r o a c h e d 5.5 C i n t h e l a t e m o r n in g o r e a r l y a f t e r n o o n ,
c u t t h r o a t t r o u t beg a n t o e n t e r t h e t r a p and t h e i r num bers
i n c r e a s e d th r o u g h o u t t h e a f t e r n o o n .
Numbers th e n d e c re a se d
r a p i d l y as evening approached when t h e str e a m t e m p e r a t u r e s
d e c re a s e d and f lo w s i n c r e a s e d due t o t h e snow m e l t a r r i v i n g
from h ig h e r e l e v a t i o n s .
I n 198 1 , t r a p s w e r e n o t u s u a l l y o p e r a t e d a t n i g h t due
t o t h e h ig h e r str e a m
f lo w s b u t were s u c c e s s f u l l y o p e r a t e d
b o t h day and n i g h t on 12 d a t e s .
On t h e s e d a y s , 90% of t h e
c u t t h r o a t t r o u t moving upstream were c a p tu r e d d u r in g t h e day
and 65% o f t h o s e moving d o w n s tr e a m d i d so a t n i g h t ( T a b le
15).
Jones e t a l.
(1982) f o u n d t h a t a l l c u t t h r o a t t r o u t
t h a t t h e y t r a p p e d i n t h e t r i b u t a r i e s o f Y e l l o w s t o n e Lake
39
moved u p s t r e a m
d u rin g th e day.
They a l s o f o u n d t h a t
downstream movement d u r in g t h e e a r l y weeks of spawning was
a s s o c i a t e d w i t h i n c r e a s e d s tr e a m f lo w s a t n i g h t ,
when t h e s e
f lo w s d e c r e a s e d l a t e r i n t h e spawning run, t h e m a j o r i t y of
downstream movment o c c u r r e d in t h e a f t e r n o o n and evenings.
Traps i n both t h e
West and E ast Forks were
r a r e l y operated
a t n i g h t i n 1982 due t o t h e s i g n i f i c a n t l y h i g h e r s t r e a m
flo w s in t h a t y e a r.
run
d aily ,
too
D u r i n g t h e few d ays t h a t t h e t r a p s w e re
few f i s h
were c a p tu r e d
to
c o n d u c t an
analysis.
Table 15.
Numbers and p e r c e n t (in p a r e n t h e s e s ) of c u t t h r o a t
t r o u t c a p t u r e d m oving u p s t r e a m and d o w n s tr e a m
d u r in g d i a l t r a p p i n g of t h e West Fork of H y a l i t e
Creek in 1981.
Numbers
moving upstream
Numbers
moving downstream
Day/
N ight
Day
Night
June 13
21
22
23
24
25
26
28
29
30
July 3
5
3
14
10
13
5
11
6
2
10
2
5
0
2
I
3
0
I
I
0
I
0
0
I
2
6
4
I
9
———
———
Totals
81(90%)
Date
———
———
9(10%)
7
3
I
2
5
7
5
2
51(35%)
8
13
8
7
2
9
18
14
93(65%)
40
Spawning P o p u l a t i o n
During 1981, a t o t a l of 236 c u t t h r o a t t r o u t were f i r s t
c a p t u r e d e n t e r i n g t h e West Fork.
p r o d u c t s when h a n d l e d .
r a t i o of 1.08:1.00.
Of t h e s e , 119 r e l e a s e d sex
T h ese f i s h had a m a le : f e m a l e s e x
This i s
s i m i l i a r t o t h e I . 2:1.0 s e x
r a t i o f o u n d by K ruse (1959) f o r c u t t h r o a t - r a i n b o w h y b r i d
t r o u t i n . s p a w n i n g r u n s a t G rebe Lake b u t l e s s t h a n t h e 1:2
sex r a t i o found by
Lund (1974) and Jones e t a l . (1982) f o r
c u t t h r o a t t r o u t i n s p a w n i n g r u n s a t Elk and Y e l l o w s t o n e
Lakes.
D u r i n g t h e 1981 s p a w n i n g r u n , 24 c u t t h r o a t t r o u t
i n i t i a l l y ta g g e d i n t h e West Fork showed no v i s i b l e p rese n ce
o f eggs or m i l t .
T hese f i s h
were l a t e r
r e c a p t u r e d and
r e l e a s e d sex p r o d u c t s when handled w i t h 18 (75%) producing
eggs.
The a d d i t i o n of t h e s e f i s h t o th o s e sexed when f i r s t
h a n d l e d r e s u l t e d i n a s e x r a t i o o f 0.88:1.00,.
These d a t a
i n d i c a t e d t h a t some f e m a l e s r i p e n w h i l e i n t h e s t r e a m and
t h a t m o s t m a l e s a r e r i p e by t h e t i m e t h e y e n t e r t h e s t r e a m s .
The f i n d i n g s o f J o n e s e t a l .
(1982) s u g g e s t e d t h i s a l s o .
The age c l a s s i f i c a t i o n o f t h e s e r i p e f i s h
in d icated
the
run c o n s i s t e d
of
fish
( T a b le 16)
I I - V y e a r s o f ag e .
M ales a p p e a r e d t o become s e x u a l l y m a t u r e e a r l i e r and w e re
s h o r te r liv e d than fem ales.
A m a j o r i t y of t h e m a l e s w ere
I I I y e a r s o f a g e and m o s t of t h e f e m a l e s w e r e IV.
Lund
(1974) found a s i m i l a r age range f o r t h e spawning c u t t h r o a t
t r o u t of Elk Lake.
41
Table 16.
The age and sex of r i p e c u t t h r o a t t r o u t c a p tu r e d
e n t e r i n g t h e West F ork of H y a l i t e C ree k d u r i n g
1981 and 1982.
Age
Ssx
Males
Females
T o t a l (%)
2(2%)
1981
II
2
0
III
41
23
64(54%)
IV
19
29
48(40%)
0
5
62
57
V
Totals
I
5(4%)
119(100%)
1962
II
8
III
35
IV
V
Totals
0
8(6%)
17
52(38%)
24
36
60(43%)
4
. 14
18(13%)
71
67
I
138(100%)
42
A ll
en terin g
of
and
the
spawning
leaving
the
age
cu tth ro at
trib u ta ries
examined f o r f l u o r e s c e n t pigm ents.
tro u t
during
captured
1981
w e re
No pigm ents were seen,
however.
D u r i n g 1 9 8 2 f a t o t a l o f 269 c u t t h r o a t t r o u t , or 16%
more t h a n i n 1981, w e r e f i r s t c a p t u r e d e n t e r i n g t h e West
F o rk .
The s e x r a t i o
o f f i s h t a k e n i n 1982 was 1 .0 6 : 1 . 0 0 ,
v i r t u a l l y t h e same a s i n 1981.
T w e n ty - o n e (95%) o f t h e 22
i n i t i a l l y u n r i p e c u t t h r o a t t r o u t were f e m a le s . The a d d i t i o n
of t h e s e t o t h e i n i t i a l l y sexed f i s h r e s u l t e d i n a sex r a t i o
of 0.89:1.00, s i m i l a r t o t h e 1981 f i n d i n g s .
As in t h e f i r s t
y e a r o f t h e s t u d y , m a l e s c o m p r i s e d a l l o f t h e age I I f i s h
c a p tu r e d in t h e run.
Unlike 1981, some males V y e a r s of age
were found. The age s t r u c t u r e of t h e 1982 run appeared t o be
s h i f t i n g t o o l d e r f i s h th a n was found in t h e 1981 run.
M a les c a p t u r e d i n t h e West F ork d u r i n g 1981 a v e r a g e d
35 mm s h o r t e r , w e ig h e d 264 g l e s s and had l o w e r c o n d i t i o n
facto rs
than
fem ales
( T a b le 17 ).
This
m a le
to
fem ale
r e l a t i o n s h i p was a l s o p r e s e n t w i t h i n age groups where both
se xes were c a p tu r e d .
I n 19 8 2 ,
m a l e s a v e r a g e d 43 mm s h o r t e r ,
w ere 289 g
l i g h t e r and had lower c o n d i t i o n f a c t o r s th a n f e m a le s .
Males
c a p t u r e d i n 1982 w e re 23 mm s h o r t e r and 133 g l i g h t e r t h a n
in 1981.
Females were 15 mm s h o r t e r and 108 g l i g h t e r th a n
i n 1981. As a r e s u l t ,
t h e mean l e n g t h
(p=0.001) , w e i g h t
43
Table 17.
The mean l e n g t h s , p r e s p a w n i n g w e i g h t s a n d
c o n d i t i o n f a c t o r s of .aged m a le and f e m a l e
. c u t t h r o a t t r o u t ( w i t h num bers i n p a r e n t h e s i s )
c a p t u r e d f i r s t e n t e r i n g t h e West Fork of H y a l i t e
C r e e k d u r i n g 1981 a n d 1982 w i t h 95 p e r c e n t
c o n f id e n c e i n t e r v a l s of a l l f i s h i n b r a c k e t s .
Mean length(mm)
Age
Males
Females
Mean
prespawning
w e i g h t (g)
Males . Females
Mean c o n d i t i o n
factor
Males
Females
1981
I I 321(2)
I I I 388(41)
IV 440(19)
V
403(23)
458(29)
499(5)
288(2)
580(37) 647(20)
866(17) 1041(27)
---1465(4).
0.835(2)
1.000 (37)
1.015(17)
Mean 402(62)
437(57)
656(56)
0.999(56)
Grand
mean
420(119)
[±8.4]
920(51)
782(107)
[±59.7]
1.020(20)
1.073(27)
1.158(4)
1.059(51)
1.027(107)
[+0.0216]
19_8L2
I I 280(8)
I I I 363(35)
IV 411(24)
V 500(4)
369(17)
424(36)
479(14)
207(6)
---468(35) 512(16)
666(19) 794(36)
899(3) 1201(14)
0.971(6)
0.970(35)
0.937(19)
0.769(3)
1.006 (16)
1.029(36)
1.078(14)
Mean 379(71)
422(67)
523(63)
0.951(63)
1.034(66)
Grand
mean
399(138)
[+9.1]
812(66)
671(129)
[+50.00]
0.993(129)
[+0.0216]
44
(p= 0 .005) and c o n d i t i o n f a c t o r
(p=0.003) f o r a l l s p a w n in g
c u t t h r o a t t r o u t c a p t u r e d i n 1982 w e r e l e s s t h a n f o r t h o s e
spawing f i s h c a p t u r e d in 1981.
B e c a u s e r i p e c u t t h r o a t t r o u t w ere f o u n d i n t h e E a s t
F ork d u r i n g 1981, a t r a p was p l a c e d i n t h i s s t r e a m on J u n e
25, 1982.
How ever, t h e s t e e p e r g r a d i e n t and h i g h s t r e a m
f lo w s p r e c l u d e d e f f i c i e n t t r a p p i n g u n t i l J u l y 4, 1982.
resu lt,
As a
Only 133 c u t t h r o a t t r o u t were f i r s t c a p tu r e d in t h e
E a s t Fork and 120 o f t h e s e w e re c a u g h t i n t h e d o w n s tr e a m
trap.
Spawning f i s h were l a s t c a p t u r e d on August 9 about
w eeks a f t e r t h e W est F ork r u n h a d ended.
c u t t h r o a t t r o u t were s i m i l a r
activ ity
of
Ages of sp a w n in g
t o t h o s e i n t h e West Fork
e x c e p t tw o age VI f i s h w e r e c a p t u r e d .
spawning
2
cu tth ro at
W e l l s (1976) fo u n d
tro u t
lim ited
alm ost
e n t i r e l y t o t h e West F ork and s p a w n i n g age g r o u p s r a n g i n g
from I I I - V .
S traying
T h i r t e e n c u t t h r o a t t r o u t s pawners were c a p tu r e d w h ile
e l e c t r o f i s h i n g t h e E a s t Fork on J u n e 30, 1981.
Of t h e s e ,
fo u r had been f i r s t caught and tagged in t h e West Fork.
Of t h e 269 c u t t h r o a t t r o u t t h a t w ere f i r s t c a u g h t and
t a g g e d i n t h e West Fork d u r i n g 1982, 46 (17%) s t r a y e d i n t o
t h e E a s t F o rk .
Of t h e 131 c u t t h r o a t t r o u t t h a t w ere f i r s t
c a u g h t and t a g g e d i n t h e E a s t Fork d u r i n g 1982, 11 (8%)
s t r a y e d i n t o t h e West F o rk .
S i n c e b o t h t r a p s w ere n o t
45
operated
continuously
minimums.
these
estim ates
of
stray in g
are
Two m a j o r r e a s o n s p r o b a b l y a c c o u n t f o r t h i s
a p p a r e n t high l e v e l of straying=
F i r s t , spawning t r a p s were
l o c a t e d a t t h e s t r e a m - r e s e r v o i r i n t e r f a c e and f i s h involve d
i n a p r e l i m i n a r y s e a r c h f o r t h e i r home s t r e a m m i g h t be
c a p t u r e d eve n th o u g h t h e y may n o t i n t e n d t o a s c e n d t h a t
str e a m . Secondly,
t h e h a t c h e r y f r y p l a n t e d in t h e r e s e r v o i r
were n o t i m p r i n t e d t o e i t h e r s tr e a m and m ight s e a r c h i n both
b e f o r e s e l e c t i n g a spawning s i t e .
Spawning Areas in t h e E ast and West Forks
The l o w e r 4.3 km of t h e West Fork a r e a v a i l a b l e t o
spawning f i s h where G r o t to F a l l s a c t s as a n a t u r a l b a r r i e r
t o f i s h movements.
I n s p e c t i o n s o f t h e West Fork d u rin g t h e
1981 spawning run i n d i c a t e d t h a t c u t t h r o a t t r o u t used o n ly
t h e l o w e r 2.0 km o f t h e West Fork f o r s p a w n i n g .
F urther
i n f o r m a t i o n was o b t a i n e d by e l e c t r o f i s h i n g t h r e e d i f f e r e n t
s e c t i o n s of t h i s s tre a m .
Twenty s p a w n i n g c u t t h r o a t t r o u t
were c a p t u r e d in t h e 1.4 km s e c t i o n from Window Rock S t a t i o n
t o t h e r e s e r v o i r on J u n e 12.
One and z e r o c u t t h r o a t t r o u t ,
r e s p e c t i v e l y were c a p t u r e d in t h e 305 m s e c t i o n s l y i n g about
2.0
and 2.7
km above
the
reserv o ir
on J u n e 24 and 30,
c o n f ir m in g e a r l i e r o b s e r v a t i o n s on spawner use of th e West
Fork.
D u rin g t h e 1981 s p a w n i n g r u n t h e f i r s t 1.6 km o f t h e
E a s t F ork w e r e a l s o i n s p e c t e d .
Spaw ning c u t t h r o a t t r o u t
46
w ere o b s e r v e d t h r o u g h o u t t h i s r e a c h b u t i n l e s s e r num bers
t h a n in t h e low er 1.4 km of t h e West Fork.
On June 30, 1981
two 305 m s e c t i o n s were e l e c t r o f i s h e d a t p o i n t s 0.3 and 1.6
km above t h e r e s e r v o i r and y i e l d e d e i g h t and f i v e c u t t h r o a t
tro u t,
respectively.
On J u l y 7 , 1982 a s e c t i o n o f t h e E a s t F ork b e g i n n i n g
about 1.6 km above t h e r e s e r v o i r and e x t e n d in g about 2.5 km
upstream was i n s p e c t e d f o r spawning c u t t h r o a t t r o u t .
Only
one spawning p a i r were observed in t h i s s e c t i o n . No spawning
c u t t h r o a t w e r e o b s e r v e d i n Hood o r B la c k m o re C r e e k s ,
the
o n l y o t h e r t r i b u t a r i e s t o t h e r e s e r v o i r , d u r i n g 1981 and
1982.
M o r t a l i t y R a tes of Spawning F ish
A to tal
of
227
m arked f i s h
entered
the
f i s h e r y f o l l o w i n g t h e s p a w n i n g r u n i n 1981.
reserv o ir
Of t h e 756
c u t t h r o a t t r o u t e x a m in e d i n t h e 1981 c r e e l , 23 o r 3% w ere
fish
m arked e n t e r i n g th e t r i b u t a r i e s .
A pplying t h i s
p e r c e n t a g e t o t h e t o t a l e s t i m a t e d h a r v e s t of c u t t h r o a t t r o u t
( T a b le 11) i n d i c a t e d t h a t a b o u t 178 o r 78% o f t h e 227 t o t a l
m arked d u r i n g
t h e 1981 s p a w n i n g
S e p t e m b e r 18 o f t h a t y e a r .
r u n w e re h a r v e s t e d by
No m arked c u t t h r o a t t r o u t w ere
found d u r in g t h e w i n t e r c r e e l survey conducted from December
21, 1981 - J a n u a r y 15, 1982 (Zubik, 1982).
However, one was
c r e e l e d d u r i n g t h e f o l l o w i n g summer making t h e e s t i m a t e d
t o t a l h a r v e s t e d i n t h e 1982 summer s e a s o n s e v e n , o r 3% of
47
the
to ta l
m arked.
T his b ro u g h t th e
e s t i m a t e d number
h a r v e s t e d i n t h e two s e a s o n s t o 184 or 81% o f t h e t o t a l
m a rk e d i n 1981.
D u rin g 1982, 16 (7%) o f t h e a d u l t s m arked
i n 1981 r e t u r n e d t o t h e West Fork and 8 (4%) r e t u r n e d t o t h e
E ast Fork.
The e s t i m a t e d numbers h a r v e s t e d and t h e numbers
r e t u r n i n g accounted f o r 92% of t h e number o r i g i n a l l y marked
in d icatin g
the
to ta l
estim ates
of
m o rtality
w ere good
approxim ations.
In 198 2 , an e s t i m a t e d 176 (45%) of t h e 389 c u t t h r o a t
t r o u t spawners marked t h a t s p r i n g had been caught and kept
by September 12.
This was w e l l below t h e 78% r a t e i n 1981.
F u rth e rm o re , m o r t a l i t y a t t h e t r a p s was o n ly 14 f i s h (3.2%)
w h ich was a l s o l e s s t h a n t h e 7.4% t r a p m o r t a l i t y fo u n d i n
1981.
T h e se r e d u c e d m o r t a l i t i e s may. r e s u l t i n a g r e a t e r
s pawner r e t u r n in 1983.
Fry
R e cruitm ent 1981
I n 19 8 1 , one d r i f t n e t was p l a c e d a t e a c h o f t h e m ouths
o f t h e W est and E a s t F o r k s on J u l y 12 and 13, r e s p e c t i v e l y ,
t o d e t e r m in e i f c u t t h r o a t t r o u t f r y were being produced in
th ese
stream s.
Fry w ere
cap tu red
in
the
n ets,
thus
i d e n t i f y i n g both s t r e a m s as producing f r y .
The c h r o n o l o g y o f f r y p r o d u c t i o n i n t h e two s t r e a m s
d i f f e r e d (F ig u re 5).
E m i g r a t i n g c u t t h r o a t t r o u t f r y w ere
48
4oor
\
r—
V V v
\/\
o
3
■o
N u m b e rs of fry
W e st Fork
E a s t Fork
100
-
Au g u st
F ig u re 5.
Septem ber
The number of c u t t h r o a t t r o u t f r y c a p t u r e d in one
d r i f t n e t i n t h e West and E a s t F o r k s of H y a l i t e
C reek and mean d a i l y s t r e a m t e m p e r a t u r e s from
August 17 - September 30, 1981.
49
f i r s t c a p t u r e d i n t h e West P ork on A u g u st 1 7 , w ere m ost
abundant on September I and were l a s t ta k e n on September 15,
1981»
In c o n t r a s t , f r y were f i r s t c a p tu r e d i n t h e East Fork
on A u g u s t 27 some 10 d a y s l a t e r t h a n t h e West F o rk .
Peak
numbers were c a p t u r e d on September 2, on ly I day l a t e r th a n
i n t h e W est F o rk .
F ry w e r e l a s t t r a p p e d on S e p t e m b e r 30,
1981, some 15 days l a t e r th a n i n t h e West Fork.
No a t t e m p t
was made t o e s t i m a t e t h e t o t a l n u m b e rs o f f r y p r o d u c e d i n
e i t h e r s t r e a m d u r i n g 1981 n o r w e r e t h e n u m b e rs c a p t u r e d
i n d i c a t i v e of t h e r e l a t i v e p r o d u c t i o n between s t r e a m s .
The d a i l y e m i g r a t i o n of f r y appeared t o be d e p r e s s e d by
low er
stream
tem p eratu res
( F i g u r e 5).
A lso,
the
la ter
e m i g r a t i o n of c u t t h r o a t t r o u t f r y in t h e E ast Fork may have
been
the
resu lt
of
its
co n sisten tly
cooler
stream
t e m p e r a t u r e s r e l a t i v e t o t h e West Fork.
N i n e t y - n i n e p e r c e n t of t h e c u t t h r o a t t r o u t f r y c a p tu r e d
moved d o w n s tr e a m a t n i g h t .
Lund (1974) f o u n d t h a t 95% o f
t h e c u t t h r o a t , rainbow and h y b r i d t r o u t f r y in Narrows Creek
moved d o w n s tr e a m b e t w e e n 2000 and 0800 and
Jones e t a l.
(1979) r e p o r t e d t h a t a b o u t 92% o f a l l c u t t h r o a t t r o u t f r y
e m i g r a t i o n from H atchery Creek o c c u r r e d a t n i g h t .
A s a m p l e o f 107 c u t t h r o a t t r o u t f r y t a k e n d a i l y f ro m
both t r i b u t a r i e s over t h e e n t i r e p e r i o d averaged 24.50 mm i n
to ta l
le n g th
and
w eighed
0.106
g
(preserved).
No
s i g n i f i c a n t d i f f e r e n c e i n l e n g t h (p>0.500) was found between
50
f r y c o l l e c t e d b e f o r e o r a f t e r peak e m i g r a t i o n .
S nyder and
Tanner (1960) and Lund (1974) r e p o r t e d t h a t c u t t h r o a t t r o u t
fry
le av in g
the
stream s
a fte r
peak
em ig ratio n
had
s i g n i f i c a n t l y g r e a t e r l e n g t h s th a n t h o s e b e f o r e .
To d e t e r m in e i f f r y were produced in t h e upper r e a c h e s
of t h e West Fork a t h r i f t r*et was i n s t a l l e d a t a p o i n t about
2.0 km above t h e r e s e r v o i r and o p e r a t e d from A ugust 27 S e p t e m b e r 14, 1981.
w h ic h
was
Only one c u t t h r o a t f r y was c a p t u r e d
con sisten t
w ith
the
evidence
obtained
from
o b s e r v a t i o n s and e l e c t r o f i s h i n g t h a t e s s e n t i a l l y no spawning
o c c u r r e d i n t h e upper r e a c h e s of t h i s strea m .
R e c ru itm e n t 1982
E m ig ra tin g c u t t h r o a t t r o u t f r y were f i r s t c a p tu r e d in
t h e s t a t i o n a r y West Fork t r a p
abundant
on S e p t e m b e r
S e p t e m b e r 27,
1982
on A u g u st 26,
w e re m o st
7 and w ere n o t c a p t u r e d a f t e r
( F i g u r e 6).
The b e g i n n i n g ,
peak and
c o m p l e t i o n o f f r y e m i g r a t i o n w e r e 1 0 , 6 arid 12 d a y s l a t e r ,
r e s p e c t i v e l y , i n 1982 t h a n i n 1981 ( F i g u r e 5).
w in ter-lik e
w eather
from
S e p te m b e r
A p e rio d of
8-16 c o o l e d s t r e a m
t e m p e r a t u r e s i n t h e West Fork and a p p e a r e d t o d e p r e s s f r y
em igration.
Numbe r of fry
51
F ig u re 6.
The t o t a l numbers of c u t t h r o a t t r o u t f r y c a p tu r e d
i n t h e s t a t i o n a r y t r a p on t h e W e s t F o r k o f
H y a l i t e Creek from August 17 - September 30, 1982
w ith mean d a i l y strea m t e m p e r a t u r e s .
52
In 1982, t h e t o t a l c u t t h r o a t f r y p r o d u c t i o n in t h e West
P ork was e s t i m a t e d t o be a b o u t 1 9 ,0 0 0
( T a b le 23),
T his
e s t i m a t e was o b t a i n e d by adding t h e numbers of f r y c a p tu r e d
in th e c o n t in u o u s ly tr a p p e d p o r t i o n of th e stre a m to those,
e s t i m a t e d t o have e m ig r a te d in t h e rem ainder of t h e str e a m
a s i n d i c a t e d by s u b s a m p l i n g .
The g r e a t e s t n u m b e rs o f f r y
p e r day w e r e c a p t u r e d a t S t a t i o n s 4 and 5 ( T a b le 23) w hich
were s i t u a t e d in t h e deeper f a s t e r p o r t i o n of th e s tre a m .
Although spawning and s u b se q u e n t f r y e m i g r a t i o n i n t h e West
F o rk w e r e l a t e r i n 1982 t h a n 19 81, t h e number o f d ay s and
t e m p e r a t u r e u n i t s between t h e i n i t i a t i o n of spawning and t h e
b e g i n n i n g o f f r y e m i g r a t i o n w e re s i m i l a r i n t h e 2 y e a r s
(Table 18).
T his same s i m i l a r i t y was a l s o found between t h e
pea k o f s p a w n i n g and pea k o f f r y e m i g r a t i o n d u r i n g b o t h
years.
T em perature u n i t s were c a l c u l a t e d by av e ra g in g t h e
d a i l y maximum and minimum s tr e a m t e m p e r a t u r e , a c q u i r i n g t h e
degrees
C elsius
above f r e e z i n g
adding t h e d a i l y v a l u e s t o g e t h e r .
by s u b t r a c t i o n and t h e n
53
Table 18.
Number o f d ay s and t e m p e r a t u r e u n i t s b e t w e e n
b eg in n in g and peak of spawning and f r y e m i g r a t i o n
f o r c u t t h r o a t t r o u t c a p t u r e d in t h e West Fork of
H y a l i t e Creek f o r 1981 and 1982.
Dates
Year
In itial
spawning
In itial
f r y e m ig r a tio n
1981
1982
May 30
Jun 10
Aug 17
Aug 22
Peak
spawning
Temperature
units
80
74
549
545
76
74
614
626
Peak
f r y e m ig r a tio n
Jun 18
Jun 26
1981
1982
Number
of days
Sep
Sep
I
7
The e n t i r e E a s t Fork was t r a p p e d i n 1982.
C utthroat
t r o u t f r y w e r e f i r s t c a p t u r e d on S e p t e m b e r 8 ( F i g u r e 7).
The number of f r y ta k e n peaked on September 19 and ended on
S eptem ber
27,
1982.
The
b eg in n in g
and peak
of
fry
e m i g r a t i o n were 12 and 14 days e a r l i e r in 1982 th a n i n 1981
( F i g u r e 5).
How ever,
co n cen trated period
E a s t F ork f r y e m i g r a t e d i n a more
and t h e r e f o r e
movement a t a b o u t t h e
same d a t e
c o m p l e t e d d o w n s tr e a m
as
i n 1981.
The 1982
e m i g r a t i o n o f f r y from t h e E a s t Fork began 13 d a y s l a t e r
t h a n i n t h e W est F ork i n 1982 ( F i g u r e 6) b u t was c o m p l e t e d
on t h e same day d u r in g t h e two y e a r s .
A t o t a l o f 2 ,8 7 8 c u t t h r o a t t r o u t f r y w e r e c a p t u r e d i n
t h e E ast Fork d u r in g 1982.
The combined t o t a l o f c u t t h r o a t
t r o u t f r y p r o d u c e d from b o t h t r i b u t a r i e s d u r i n g 1982 was
54
e
3
e
m
3
e
3
■o
N u m b e rs of fry
800
Au g u st
F ig u re 7.
O
''" Tem
----- Fry
Septem ber
The t o t a l number of c u t t h r o a t t r o u t f r y c a p tu r e d
e m i g r a t i n g from t h e E a s t Fork of H y a l i t e C reek
from A u g u st 17 - S e p te m b e r 30, 1982 w i t h mean
d a i l y stream t e m p e r a t u r e s .
55
t h e r e f o r e e s t i m a t e d t o be about 22,000.
R e c r u itm e n t t o t h e 1982 y ea r c l a s s may have been lower
th a n t o t h e 1981 y e a r c l a s s .
The d r i f t n e t used in t h e E ast
F o rk d u r i n g 1981 was p l a c e d a l o n g t h e edge o f a t y p i c a l U-.
shaped c r o s s s e c t i o n of s tr e a m bottom and sampled about 17%
of th e stream w idth.
T h i s n e t c a p t u r e d 2 ,3 5 1 c u t t h r o a t
t r o u t f r y w h i l e o n l y a b o u t 500 more f r y w e r e c a p t u r e d i n
1982 when t h e e n t i r e s t r e a m was t r a p p e d .
low er
p roduction
may h a v e r e s u l t e d
d i s c h a r g e s d u r in g spawning.
w ere
3 .7
and
resp ectiv ely .
5.4
m3
T his a p p a re n t
from h i g h e r
stream
In 1982, peak s tr e a m d i s c h a r g e s
for
the
East
and
W est
F orks,
I n 198 1 , peak f l o w s w e r e 2.6 and 4.5 in3 f o r
t h e E a s t and West F o r k s , r e s p e c t i v e l y .
Mean p e a k s t r e a m
f l o w s f ro m 1975 - 1982 w e re 3.0 and 5.0 m3 f o r t h e E a s t and
West Forks, r e s p e c t i v e l y .
B ulkley and Benson (1962), F a m e s
and B u l k l e y (1964) and Drummond and McKinney (1965) h a v e
r e p o r t e d an i n v e r s e c o r r e l a t i o n between str e a m flow d u r in g
c u t t h r o a t t r o u t s p a w n i n g p e r i o d s and t h e r e s u l t i n g y e a r
class strength.
P ro d u c tio n i n t h e West Fork d u r in g 1981 and
1982 c o u ld n o t be compared because, d i f f e r e n t sampling s i t e s
were used i n t h e 2 y e a r s .
R earing
A 305 m s e c t i o n o f t h e West Fork a t t h e Window Rock
S t a t i o n (F igure I) was e l e c t r o f i s h e d on October 21, 1981 and
b a i t e d minnow t r a p s were f i s h e d in observed spawning re a c h e s
56
of
the
E a s t and West F o r k s from J u n e 11 - 14,
d eterm in e
if
trib u taries.
tro u t
fry
reared
in
th ese
No w i l d c u t t h r o a t t r o u t f r y were c a p tu r e d by
e i t h e r m e th o d .
and T an n er
cu tth ro at
1982 t o
T h i s f i n d i n g was s i m i l a r t o t h a t o f S nyder
(I960)
who e s t i m a t e d t h a t l e s s t h a n 1% o f
c u t t h r o a t t r o u t f r y remained in Cabin Creek a f t e r e m i g r a t i o n
b u t i n o p p o s i t i o n t o t h o s e o f Lund (197 4) and B u l k l e y and
Benson (1962) who f o u n d t h a t some and many c u t t h r o a t t r o u t
f r y r e m a i n e d i n N a rro w s and P e l i c a n C r e e k s , r e s p e c t i v e l y ,
d u r in g t h e i r f i r s t w i n t e r .
E l e c t r o f i s h i n g and b a i t e d minnow t r a p s d i d , h o w e v e r ,
c a p t u r e a t o t a l o f 43 m arked h a t c h e r y f i s h i n t h e E a s t and
West Forks d u rin g 1981 and 1982 (Table 24). C u t t h r o a t t r o u t
w i t h r i g h t - p e l v i c f i n c l i p s were c a p t u r e d i n t h e West Fork
d u r i n g O c t o b e r , 1981 and i n b o t h t h e E a s t and West F o r k s
d u r in g Ju n e , 1982 i n d i c a t i n g t h a t t h e s e h a t c h e r y f r y ,
w e re
planted
in
the
reserv o ir
on A ugust 1 8 ,
1981,
e n t e r e d and o v e r w i n t e r e d i n a t l e a s t t h e West F o rk .
which
had
F ish
b e a r i n g o t h e r m a rk s t h a t had bee n p l a n t e d i n t h e r e s e r v o i r
i n 1979 and 1980 were a l s o c a p t u r e d in t h e West Fork d u rin g
both y e a r s i n d i c a t i n g t h a t th e y to o remained in t h a t str e a m
for a t le a s t 2 years.
A lso,
some h a t c h e r y f i s h p l a n t e d
d i r e c t l y i n t o t h e s t r e a m may r e m a i n t h e r e f o r a t l e a s t 2
years.
57
Age and Growth
Back C a l c u l a t e d Lengths a t Age
The bac k c a l c u l a t e d l e n g t h s a t a n n u l u s f o r unmarked
c u t t h r o a t t r o u t c o l l e c t e d i n 1982 show t h a t g r o w t h r a t e s
w e r e s i m i l i a r and m o s t r a p i d i n t h e f i r s t and s e c o n d y e a r o f
l i f e and t h e n p r o g r e s s i v e l y d e c l i n e d t h r o u g h a g e V ( T a b le
19).
Table 19.
The average c a l c u l a t e d t o t a l l e n g t h a t a n n u l i and
annual in c r e m e n t s of growth f o r c u t t h r o a t t r o u t
of H y a l i t e R e s e r v o i r c o l l e c t e d from June September, 1982.
Number .
Age
group (% of t o t a l )
Mean.
length a t
capture
I
2
3
4
5
127
141
137
140
225
273
306
329
326
375
401
417
446
490
Grand mean
137
279
3 57
425
490
Increm ents
137
142
78
68
65
Number 217(100%)
217
217
169
92
25
II
III
IV
V
48(22%)
77(35%)
67(31%)
25(12%)
The o l d e r
254
332
422
491
th e age g ro u p of f i s h
used in th e back
c a l c u l a t i o n t h e g r e a t e r t h e l e n g t h f o r age I I and o l d e r
fish .
T h i s phenomenon was a l s o fo u n d i n t h e o t h e r t h r e e
bac k c a l c u l a t i o n s m e th o d s t e s t e d .
T h i s may r e f l e c t t h e
p o p u l a t i o n expansion of t h e McBride Lake s t r a i n .
first
p lan ted
They were
i n 1976 when Y e l l o w s t o n e c u t t h r o a t
tro u t
58
numbers i n t h e r e s e r v o i r were low (Wells, 1976) which would
have r e s u l t e d in more food a v a i l a b l e per f i s h i n i t i a l l y th a n
d u r in g l a t e r y e a r s when t h e p o p u l a t i o n i n c r e a s e d .
About 6% of a l l t h e c u t t h r o a t t r o u t examined had s c a l e s
w hich a p p e a r e d t o
be m i s s i n g
a first
a n n u l u s and w e re
c o n s e q u e n t l y e x c l u d e d from t h e a g e and g r o w t h a n a l y s i s .
Brown and B a i l e y
(1952)
d o c u m e n te d
th is
c u t t h r o a t t r o u t f r y from Y e l l o w s t o n e Lake.
phenomenon
in
A l l o f t h e 31
age I r i g h t - p e l v i e c l i p p e d h a t c h e r y c u t t h r o a t t r o u t c a p tu r e d
d u rin g
June,
1982
appeared
to
have
a first
annulus
i n d i c a t i n g t h a t some w i l d c u t t h r o a t t r o u t p r o d u c e d i n t h e
t r i b u t a r i e s may n o t form a f i r s t annulus.
The ave ra ge back c a l c u l a t e d l e n g t h s a t age f o r McBride
Lake c u t t h r o a t t r o u t c o l l e c t e d i n 1982 w e re 1 4 , 63, 47 and
45 mm g r e a t e r
for
ages
c o m p a ra b le age g ro u p s of
I-IV
resp ectiv ely ,
w ild -ap p earin g
than
for
Y ello w sto n e
c u t t h r o a t t r o u t c o l l e c t e d i n 1974 and 1975 ( W e l l s , 1 976).
A v e r a g e a n n u a l back c a l c u l a t e d i n c r e m e n t s o f g r o w t h f o r
McBride f i s h w e r e 14 and 49 mm g r e a t e r t h a n a g e s I and I I
b u t 16 and 2 mm l e s s t h a n age I I I and IV w i l d - a p p e a r i n g
Y ellow stone c u t t h r o a t t r o u t c a p t u r e d in 1974 and 1975.
Growth of Tagged F ish
The growth i n c r e m e n ts f o r c u t t h r o a t t r o u t c a p tu r e d in
1981 and th e n r e c a p t u r e d i n t h e 1982 spawning runs a r e shown
59
in Table 20.
Mean growth in c r e m e n ts f o r each age group was
sig n ific an tly
less
th an
mean b a c k
i n c r e m e n ts of unmarked f i s h (Table 19).
ta g g in g or th e p h y s io l o g ic a l s t r e s s
calcu lated
grow th
This i n d i c a t e s t h a t
of c o n s e c u t i v e y e a r
spawning or both i n h i b i t e d growth.
Table 20.
The mean t o t a l l e n g t h s w i t h 95 p e r c e n t co n fid e n c e
i n t e r v a l s ( i n p a r e n t h e s e s ) and a n n u a l g r o w t h
i n c r e m e n ts of c u t t h r o a t t r o u t marked i n 1981 and
r e c a p t u r e d in 1982.
Year
1981
Number
3
5
11
I
Age
II
III
IV
V
1982
Mean
length(mm)
Age
Mean
length(mm)
310(±27)
399(±12)
468(±27)
495
III
IV
V
VI
332(±48)
410 (±14)
485(±30)
508
Growth
increment(mm)
22
11
17
13
Growth of Known Age F is h
Age 0 h a t c h e r y f i s h were about 38 mm l a r g e r th a n t h e i r
w i l d c o u n t e r p a r t s when th e y were p l a n t e d in t h e r e s e r v o i r in
A u g u s t , 1.981 ( T a b le 2 1 ) .
They m a i n t a i n e d t h e i r a d v a n t a g e
o v e r w i n t e r and w e r e 35 mm l a r g e r
in J u n e 1982.
(1976) a l s o found t h a t i n c r e m e n ts of growth
m a rk e d ,
hatchery c u tth ro a t
W ells
f o r known age,
t r o u t w ere s i m i l i a r
t o back
c a l c u l a t e d i n c r e m e n ts of growth f o r w i l d - a p p e a r i n g c u t t h r o a t
tro u t.
60
Table 21.
The mean l e n g t h of known age h a t c h e r y and w i l d
c u t t h r o a t t r o u t examined a t H y a l i t e R e s e r v o ir .
Wild
Hatc hery
Date
Mean
length
Age
Aug, 81
Ju n , 82
0
I
65*
89
Number
Mean
length
22,178
31
25
54
Number
109
2
^Determined by p e r s o n n e l of t h e Big Timber H atc h ery , MDFWP
F ifteen
known
age
I
hatch ery
cu tth ro at
(dete rm in ed by f i n c l i p s or f l u o r e s c e n t pigments)
tro u t
c a p tu r e d
i n t h e E a s t and West F o r k s d u r i n g J u n e o f 1981 and 1982
a v e r a g e d 96 mm TL.
the t r i b u r t a r i e s
E i g h t known age I I h a t c h e r y f i s h f ro m
a v e r a g e d 133 mm i n J u n e o f t h e 2 y e a r s
w h i l e bac k c a l c u l a t e d age I I f i s h from t h e r e s e r v o i r w e re
146 mm l a r g e r .
T h ese p oor g r o w t h r a t e s w e r e p r o b a b l y a
r e s u l t o f low p r o d u c t i v i t y and c o l d t e m p e r a t u r e s i n t h e
trib u taries
(Table I ) .
61
DISCUSSION
The
fish ery
of
H yalite. R e s e rv o ir
has
in creased
d r a m a t i c a l l y s i n c e i t was l a s t s t u d i e d 7 y e a r s ago.
In 1981
and 1982 combined, t h e summer f i s h i n g p r e s s u r e had i n c r e a s e d
by 109%,
catch
rates
w e r e 67%
g reater,
harvest
had
i n c r e a s e d by 221% and t h e b i o m a s s o f t h e h a r v e s t i n c r e a s e d
by 150% compared t o t h o s e p a r a m e t e r s from t h e combined 1974
and 1975 s e a s o n s f o r c u t t h r o u t t r o u t (Table 22). The p r e s e n t
summer c r e e l survey c o n s i s t e d of 14 weeks y e a r l y w h ile W ells
(1976) survey c o n s i s t e d of 12 weeks y e a r l y , however.
These
measured i n c r e a s e s were f a r g r e a t e r th a n t h o s e caused by t h e
p o p u l a t i o n growth in t h e s u r ro u n d in g a r e a a l o n e ,
indicating
t h a t l o c a l f is h e rm e n in c r e a s e d t h e i r use of th e r e s e r v o i r
considerably.
C ounty
(P.
From 1 9 7 5 - 1 9 8 1 , t h e p o p u l a t i o n i n G a l l a t i n
Brooks,
p e r s.
comm.)
was e s t i m a t e d
to
have
i n c r e a s e d from a b o u t 37,900 t o 43,300 (14%) w h i l e f i s h i n g
p r e s s u r e a p p r o x im a te l y doubled.
Table 22.
Year
The sum m er f i s h i n g p r e s s u r e s , c a t c h r a t e s ,
n u m b e rs h a r v e s t e d and b i o m a s s h a r v e s t e d f o r
c u t t h r o a t t r o u t a t H y a l i t e R e s e r v o ir in 1974 and
1975 and t h e p r e s e n t stu d y .
P r e s s u r e (h)
Catch r a t e
(fish/h)
Numbers
harvested
Biomass
h a r v e s t e d (kg)
1974
1975
9,663
8,384
0.19
0.11
2,318
764
726
595
1981
1982
19,981
17,733
0.27
0.23
5,862
4,032
2,019
1,349
62
The
in tro d u ctio n
of
the
McBride
Lake
strain
in to
H y a l i t e R e s e r v o i r h a s c r e a t e d an im p r o v e d f i s h e r y t h a t i s
now s u p p o r te d by in d ig e n o u s r e p r o d u c t i o n .
Both t h e West and
E a s t F o r k s o f H y a l i t e C reek a r e d o c u m e n te d s p a w n i n g a r e a s
producing w ild r e c r u i t s fo r th e f is h e r y .
Even w i t h t h e
s e v e r e c r o p p in g of spawning age f i s h by a n g l e r s , i t appeared
t h e age s t r u c t u r e o f t r a p p e d s p a w n e r s was moving t o w a r d s
o ld er f i s h ,
recru its
p e rh a p s i n d i c a t i n g a g r e a t e r p r o d u c tio n of
in th e f u t u r e .
MDFWP s t o c k e d t h e
B e c a u se o f t h e s e f i n d i n g s ,
reserv o ir
only
i n 1981 and p l a n s
the
no
fu rth e r plantings.
I n a d d i t i o n t o t h e summer f i s h e r y , H y a l i t e R e s e r v o i r
has su p p o rted a popular ic e f i s h e r y fo r lo c a l a n g le rs in
recent years.
A p a r t i a l c r e e l census conducted a t n ig h t
from December 21, 1981 - J a n u a r y 15, 1982 showed f i s h i n g
p r e s s u r e was 1,0 7 8 ( + 435) h , c a t c h r a t e 1.4 (±0.2) f i s h p e r
h o u r and h a r v e s t was 1,454 (+639) c u t t h r o a t t r o u t d u r i n g
t h i s p e r i o d (Zubik, 1982).
The s i z e of t h i s w i n t e r f i s h e r y
l a r g e l y d e p e n d s upon t h e l e n g t h o f t i m e t h e r o a d t o t h e
r e s e r v o i r i s kept open.
During t h e w i n t e r of 1981-1982, t h e
r o a d was n o t p lo w e d and c o n s e q u e n t l y t h e r e s e r v o i r
was
a c c e s s i b l e t o w h e e l e d v e h i c l e s f o r a b o u t 46 f i s h i n g d a y s .
I n some y e a r s ,
t h e . r o a d i s p lo w e d t h r o u g h o u t t h e w i n t e r
m aking t h e r e s e r v o i r a v a i l a b l e t o f i s h e r m e n u n t i l m e l t i n g
snows f o r c e road c l o s u r e s i n t h e s p r i n g .
The F o r e s t S e r v i c e
63
p r e s e n t l y p l a n s t o pave t h e g r a v e l road t o t h e r e s e r v o i r by
1985 and may a l s o kee p i t . p l o w e d d u r i n g t h e w i n t e r m o n th s .
This co u ld cause a d r a m a tic
in crease
i n t h e w i n t e r and
summer f i s h i n g p r e s s u r e and r e d u c e t h e p r e s e n t q u a l i t y o f
the
fish ery .
P erio d ic
m onitoring
w ill
be
required
to
p r o v i d e t h e m anagem ent d a t a n e e d e d t o m a i n t a i n t h i s h i g h
q u a l i t y c u t th r o a t t r o u t f is h e r y a t H yalite Reservoir.
The
e s t a b l i s h m e n t of McBride Lake c u t t h r o a t t r o u t i n H y a l i t e
Reservoir
u sing
documents t h e
a strain
particular
and
fish
environment.
b io tic
w hich
the
management s t r a t e g y of
is
b etter
su ited
In w a t e r s w i t h s i m i l i a r
c h a ra cte ristic s
d eterio ra ted ,
recommended.
of
successful
w here
in tro d u ctio n
of
the
th is
to
a
chemical
fish ery
strain
has
is
REFERENCES CITED
65
REFERENCES CITED
Benson, N0 G. 1960,
F a c t o r s i n f l u e n c i n g p r o d u c t i o n of
immature c u t t h r o a t t r o u t in A rnica Creek, Y ellowstone
P ark. T ra n s. Amer. F i s h . Soc. 8 9 ( 2 ) : 168-175.
Brown, C. J . D., and J . E. B a i l e y . 1952. Time and p a t t e r n
of s c a l e fo rm a tio n in Y ellow stone c u t t h r o a t t r o u t ,
Salmo c l a r k i l e w i s s i i . T rans, of Amer. Microscop. Soc.
71(1): 22-42.
B u l k l e y , R. V., and N. G. Benson. 1962. P r e d i c t i n g y e a r c l a s s a b u n d a n c e o f Y e l l o w s t o n e Lake c u t t h r o a t t r o u t .
U.S. F i s h . W i l d l . S e r v . Res. Rep. 59, 21 pp.
Chadwick, R. A. 1969. The n o r t h e r n G a l l a t i n Range, Montana:
N o rth w e ste rn p a r t of t h e Absaroka - G a l l a t i n v o l c a n i c
field .
C o n trib . t o Geology 8:150-166.
Univ. Wyoming,
Laramie.
Drummond, R. A. and H. A. T a n n e r . 1960. R e p r o d u c t i o n and
h a r v e s t of c u t t h r o a t t r o u t a t T r a p p e r s L ake, Colo.
Colo. Coop. F ish . Res. U nit, F t. C o l l i n s , 7:1-19.
Drummond, R. A., and T. D. McKinney. 1965. P r e d i c t i n g t h e
r e c r u i t m e n t o f c u t t h r o a t t r o u t f r y i n T r a p p e r s Lake,
C o l o r a d o . T r a n s . Amer. F i s h . Soc. 9 4 ( 4 ) : 3 8 9 -3 9 3 .
F a m e s , P. E., and R. V. B u l k l e y . 1964. F i s h e r y management
of Y ellow stone Lake, Wyoming a s r e l a t e d t o w ater supply
f o r e c a s t s . P r o c . 32nd Annual W e s t e r n Snow C o n f ., 2731.
H e s s e , L.
1977.
F i r e I , a com puter program f o r th e
c o m p u ta tio n of f i s h e r y s t a t i s t i c s w ith aged and nonaged
s u b s a m p l e s . IBM360/65, F o r t r a n IV G l e v e l .
E. H u f f ,
e d i t o r . N e b r a s k a Game and P a r k s C o m m issio n , L i n c o l n .
Neb. Tech. S e r . , No. I . 60 pp.
J o n e s , R. D., G r e s s w e l l , R. E., J e n n i n g s , D. E., L e n t z , D.
C . , R u b r e c h t , S. M., V a n D e v e n te r , J . S. and V a r l e y , J .
D. 1 9 7 9 .
A nnual p r o j e c t r e p o r t ^ f i s h e r y and and
a q u a t i c managment program i n Y ellow stone N a ti o n a l Park,
c a l e n d a r y e a r 1978. U.S. F i s h a n d ' W i l d l i f e S e r v i c e ,
Mammoth, Wy. Unpublished mimeo. 311 pp.
66
____________ r ________________ r Valdez, R. A. and Beigelow , P.
E. 1982. Annual p r o j e c t r e p o r t f i s h e r y and a q u a t i c
managem ent p r o g ra m in Y e l l o w s t o n e N a t i o n a l P a r k ,
C a l e n d a r y e a r 1981. U.S. P i s h and W i l d l i f e S e r v i c e ,
(
Mammoth, Wy. Unpublished mimeo. 179 pp<
Kruse, T. E. 1959. The g r a y l i n g of Grebe Lake, Y ellowstone
N a t i o n a l P a r k , Wyoming.
U.S. F i s h a n d W i l d l i f e
Service.
F ish .
B u l l . 149(59) :307-351.
Lund, J . A. 1974. The r e p r o d u c t i o n o f s a l m o n i d s i n t h e
i n l e t s of Elk L a k e , Montana. M. S. T h e s i s , Montana S t .
Univ., Bozeman.
43 pp.
L u n d , R. E.
1979.
A u s e r ' s g u i d e t o MSUSTAT--an
i n t e r a c t i v e s t a t i s t i c a l a n a l y s i s package.
D ept, o f
Math. S c i . , Montana S t . U n iv ., Bozeman. 74 pp.
M a rc u s, M. D., S c h i l l i n g e r , J . E. and S t u a r t , D. G. 1978.
L im n o lo g ic a l s t u d i e s in Montana: H y a l i t e R e s e r v o ir and
r e s p o n s e s of l o t i c p e r i p h y t o n t o d e e p -w a te r d i s c h a r g e s ,
g r a z i n g , and l o g g i n g . Montana S t . Univ. J o i n t w a t e r
R e s e a r c h C e n t e r , Montana S t . U n i v . , Bozeman. Rep 92.
156 pp.
Montana D e p a r t m e n t o f F i s h and Game. 1979. N o rt h Fork o f
t h e F l a t h e a d R i v e r F i s h e r i e s I n v e s t i g a t i o n s R p t . 73
pp.
N e u h o ld , J . M. and K. H. Lu. 1957. C r e e l c e n s u s m ethod.
U tah S t a t e D ept, o f F i s h and Game, P u b l. No. 8, S a l t
Lake C i t y , U tah. 36 pp.
N ie, N. H., C. H. H u l l , J . G. J e n k i n s , K. S t e i n b r e n n e r and
D. H. B e n t . 1975. S t a t i s t i c a l p a c k a g e f o r t h e s o c i a l
s c i e n c e s , 2 ed. McGraw-Hill, I n c ., New York. 675 pp.
P o o r e , M. D. 1973. The f i s h e r y r e s o u r c e of M y s t i c L ake,
M ontana.
M.S. T h e s i s .
Mont. S t a t e U n i v . , Bozeman,
Mont. 31 pp.
P o r t e r , T. R. 1973.
F ry e m e r g e n c e t r a p and h o l d i n g box.
P ro g .
F ish C u lt. 35(2): 104-106.
S n e d e c o r , G. W. and W. G. C o c h ra n .
1967.
S tatistical
M e th o d s , 6 ed. Iowa S t . Univ. P r e s s , Ames. 593 pp.
S n y d e r , G. R., and H. A. T a n n e r .
1960.
C utthroat tro u t
r e p r o d u c t i o n in t h e i n l e t s t o T rappers Lake. Colorado
Dept, of Game and F i s h , Tech. B u l l . No. 7 , 86 pp.
67
U. S . E n v i r o n m e n t a l P r o t e c t i o n A g e n c y ,
c r i t e r i a for water.
Washington, D.C.
197 6 .
Q uality
256 pp.
W e lls, J. D. 1976. The f i s h e r y of H y a l i t e R e s e r v o ir du rin g
1974 a n d 1 9 7 5 . M. S. T h e s i s , M o n t a n a S t .
U niv.,
Bozeman. 47 pp.
Z u b i k , R. J . 1 9 8 2 .
A w i n t e r c r e e l c e n s u s on H y a l i t e
R e s e r v o ir d u rin g 1981-1982. Survey r p t . t o d i s t r i c t
r a n g e r , G a l l a t i n N a t i o n a l F o r e s t , Bozeman. 5 pp.
68
APPENDIX
69
T a b l e 23.
The num b e rs of c u t t h r o a t t r o u t f r y c a p t u r e d a t
s a m p l i n g s t a t i o n s on t h e West Fork o f H y a l i t e
C reek from A u g u st 26 - S e p t e m b e r 27, 1982.
P e r c e n t a g e s e x p r e s s t h e r e l a t i o n s h i p of t h e
num b e rs t a k e n a t t h e s u b s a m p l e d s i t e s t o t h e
num bers ta k e n a t th e s t a t i o n a r y sa m p lin g
s i t e (Station I ) .
Sample s t a t i o n
I
2
8
9
10
11
18
19
20
21
22
23
24
25
26
27
Total
152
69
103
103
135
68
89
38
26
13
13
11
I
I
823
Sep 12
13
T o ta l
38
44
82
Sep 14
15
Total
22
46
68
Sep 16
17
T o ta l
37
90
127
Sep
E stim a te d
station
2,004
to tals
E s tim ate d
Grand T o ta l
~3
4
:
5
407
494
210
210
201
242
307
255
213
91
51
93
61
20
2,855(347%)
170
101
271(330%)
30
33
63(93%)
29
93
122(96%)
1,924
19, 359
1,864
6,613
6,6954
70
Table 24.
The d a t e s and l o c a t i o n of marked h a t c h e r y McBride
c u t t h r o a t t r o u t f r y p l a n t s l a t e r r e c a p tu r e d in
t h e E a s t and West F o rk s of H y a l i t e Creek.
Plants
Date
Mark
R e c a p tu re s
L o c a tio n
Date
L o c a tio n Number
Sep, 1979 Red pigment
R e s e r v o ir
J u n , 1981 West Fork
I
Sep, 1979 L i g h t green
pigment
West Fork
Oct, 1981 West Fork
Ju n , 1981 West Fork
I
5
J u l , 1980 Orange
pigment
West Fork
J u n , 1982 East Fork
Oct, 1981 West Fork
Ju n , 1981 West Fork
2
5
7
Aug, 1981 R i g h t - p e l v i c
clip
R e s e r v o ir
Ju n , 1982 West &
E ast Forks 8
. Oct, 1981 West Fork 14
M O N TA N A ST A T E U N IV E R SIT Y L IB R A R IE S
3 1762 00178203 4
«7 -