71 - 18,254

MENSE, James Burr, 19++2—
RELATION OF DENSITY TO BROWN TROUT MOVEMENT IN
A MICHIGAN STREAM.
Michigan Stale University, Ph.D., 1970
Zoology

U n iversity M icrofilm s, A XEROX C om pany , A nn Arbor, M ich igan

R E L A T I O N O F D E N S I T Y T O B R O W N TR O U T M O V E M E N T
IN A M I C H I G A N S T R E A M
By
Jam es Bi' Mense

A THESIS
S u b m i t t e d to
M i c h i g a n St ate U n i v e r s i t y
in p a r t i a l f u l f i l l m e n t of the r e q u i r e m e n t s
for the d e g r e e of
D O C T O R OF P H I L O S O P H Y
D e p a r t m e n t of F i s h e r i e s and W i l d l i f e
1970

ABSTRACT
RE L A T I O N OF D E N S I T Y TO B R O W N T R O U T M O V E M E N T
IN A M I C H I G A N S T R E A M
By
J a m e s B. M e n s e
It has b een s u g g e s t e d that a m o n g t e r r i t o r i a l s t r e a m
fishes

t e r r i t o r i a l c o m p e t i t i o n m ay i n c r e a s e as d e n s i t y

i n c r e a s e s ab ov e some t h r e s h o l d level,
c r e a s e in c o m p e t i t i o n res u l t s
in the p r o p o r t i o n of n o m a d i c
this

and t h a t this

in­

in a c o r r e s p o n d i n g i n c r e a s e
fish in the p o p u l a t i o n -

If

is true it seems r e a s o n a b l e to as s u m e that the d e g r e e

of m o v e m e n t

shown by the p o p u l a t i o n as a w h o l e w o u l d

c r e a s e also.

To te st this h y p o t h e s i s

in­

a st udy of the r e l a ­

t i o n s h i p b e t w e e n tro ut d e n s i t y and the m o v e m e n t p a t t e r n s
of b r o w n tro ut was under tak en.
D u r i n g the summer of 196 8 a m a r k a nd r e c a p t u r e
e x p e r i m e n t was p e r f o r m e d on the b r o w n trout

in a 1 4 0 0 - f o o t

s e c t i o n of the Pine Riv er in I s a b e l l a County.
was d i v i d e d int o seven,

a d j a c e n t 2 0 0 - f o o t s tat i o n s

trout f rom each s t a t i o n and o v e r 6- in c h e s
w e re m a r k e d d i s t i n c t i v e l y .
106 r e c a p t u r e s

T his

se cti on
and

in total l e n g t h

Dat a on m o v e m e n t o b t a i n e d from

in 19 6 8 i n d i c a t e d that tr out m o v e m e n t was

o r i e n t e d a r o u n d the s t a t i o n of i n i t i a l capture.

J a m e s B„ M e n s e
In 1969
planned,

a r e p e t i t i o n of the a bov e e x p e r i m e n t was

w i t h the i n c l u s i o n of two n e w sections.

f o l l o w i n g r e d u c t i o n of the p o p u l a t i o n ,
r e c a p t u r e e x p e r i m e n t wa s planned.

Then,

a n o t h e r m a r k and

Ho we v e r ,

d u r i n g the

c o u r s e of s a m p l i n g in 1969 it b e c a m e a p p a r e n t t hat a d e ­
c r e a s e in a b u n d a n c e of tro ut o v e r 6 - i n c h e s
already occurred,
ment.

p r o b a b l y as a r e s u l t o f r e d u c e d r e c r u i t ­

Schnabel estimates

number,

in le n g t h had

i n d i c a t e d a 54.4% r e d u c t i o n in

w h i l e s u b t r a c t i o n of the r e c r u i t m e n t e s t i m a t e

the e s t i m a t e d m o r t a l i t y

i n d i c a t e d a 55.7%

from

reducti on.

M a n i p u l a t i o n of d e n s i t y w a s t h e r e f o r e u n w a r r a n t e d .
D i s t r i b u t i o n of the 97 r e c a p t u r e s of
in 1969

indicated that trout movement

se ctions was
ture,

in e a c h o f the t h r e e

o r i e n t e d a r o u n d the s t a t i o n of ini t i a l

just as in 1968.

for trout

fish m a r k e d

in the thr ee

Moreover,
sections

cap­

the m o v e m e n t p a t t e r n s

s a m p l e d in 1969 d id not

d i f f e r fr om the p a t t e r n r e c o r d e d in 1968It is s u g g e s t e d that a p o s i t i v e r e l a t i o n s h i p b e ­
tween d e n s i t y and the d e g r e e o f m o v e m e n t
tr out p o p u l a t i o n s exists,

b ut tha t it p r o b a b l y oc c u r s

p r i m a r i l y am o n g the fry and b e c o m e s
by the time the

shown by b row n

considerably diminished

fish r e a c h 6 - i n c h e s in length.

s u g g e s t e d th at this

relationship operates

regulating mechanism,

It is

as a d e n s i t y

with primary regulation occurring

J a mes B, M e n s e
be f o r e the

fish r e a c h r e p r o d u c t i v e age.

This m e c h a n i s m

w o u l d th en act to c o n s e r v e e n e r g y and in s u r e a d e q u a t e
reproduction.

ACKNOWLEDGMENTS
I w i s h to e xp r e s s

a p p r e c i a t i o n to Dr. N i l e s K e ve r n

for his h e l p a nd g u i d a n c e t h r o u g h o u t
William Cooper

for l e n d i n g

Dr.

s tu d y an d to Dr.

i n spiration.

T o my c o m m i t t e e memb ers,
R obert Ball,

this

Dr. N i le s Kevern,

Dr.

H o w a r d J o h n s o n and Dr. W i l l i a m Cooper,

w i s h to e x t e n d m y t h a n k s

I

for c r i t i c i s m s ma d e d u r i n g p r e p a ­

r a t i o n of this m a n u s c r ip t *
Particular

appreciation

is als o e x t e n d e d to the D o w

C h e m i c a l C o m p a n y and the M i c h i g a n A g r i c u l t u r a l E x p e r i m e n t
S ta t i o n

for t he i r

f i na n ci a l s u pport d u r i n g the c o u r s e o f

this study.
Thanks

als o go to

B arber an d F r a n k T e s a r
w ater c h e m i s t r y data;
the ag i ng o f fish;

fe l l o w g r a d u a t e st u d e n t s W i l l a r d

for their n u me r o u s t r i p s to g at h er
Th o m a s Mears,

w h o c o r r o b o r a t e d in

and S t e v e n Sp igarelli,

s am p l i n g w h e n h e l p w a s

scarce.

w h o h e l p e d in

T A B L E OF C O N T E N T S
Page
LIST OF T A B L E S .............................. . ...........

iv

LIST OF F I G U R E S ................................................vi
INTRODUCTION

.........................

TH E ST UDY A R E A

. . . . . . .

............................

METHODS AND MATERIALS

.................

0 r

. . . . . . .

. . . . . . . .

1
3
10

D i v i s i o n of the S tud y A r e a ...........................
F ish S a m p l i n g ............................................

10
11

R E S U L T S ......................................... ...........

17

The Fis h P o p u l a t i o n .......................„ ...........
The B r o w n T r o u t P o p u l a t i o n
..........................
Population Density
.
A g e and Size S t r u c t u r e .......................... „ .
M o v e m e n t a nd S t a b i l i t y
.......... . . . . . . . .
DISCUSSION

. .................................. „

. . . .

17
22
22
26
32
52

S U M M A R Y ............................
LITERATURE CITED
APPENDIX

. . ...............

„ . .
. . .

.......................................

ill

63
. . . . .

68

L I S T OF T A B L E S

W a t e r c h e m i s t r y of the P ine R i v e r at the
B l a n c h a r d Roa d bridge, I s a b e l l a County,
M i c h i g a n , d u r i n g 1968 and 1969 . . «. .

. * *

Types of fi n-c Lip s u sed to m a r k b r o w n t r o u t
fr om 21 s t a t i o n s in the Pi ne River d u r i n g
........................ .
.
, . „
1968 and 1969
A b u n d a n c e of fishes in e l e c t r i c s h o c k e r
sa mples t a k e n f r o m the N o r t h Br a n c h of the
P i ne R i v e r d o w n s t r e a m f r o m B r i n t o n R oad
d u r i n g Au gu s t , 196 8 and 1969 ( A ) , and a
s a m p l e t a k e n u p s t r e a m fro m B r i n t o n Road
d u r i n g September, 1968 (B) . . - . . . .
. . Age and g r o w t h o f 97 b r o w n trout ta k en fr om
the Pi n e R i v e r s t u d y area on A u g u s t 11 and
25, 1969 ............................. .. ............
E s t i m a t e s of the nu m b e r of m a r k e d b r o w n t rou t
in eac h age class, the p e r c e n t a g e of the
p o p u l a t i o n c o n t r i b u t e d by e ach age class
and the ran ges in t ota l le ngth for e ach age
class for thr ee m o n t h s d u r i n g 1968 a n d 1969
T o t a l n u m b e r a nd p e r c e n t a g e of br o w n t r o u t
r e c a p t u r e s m a d e at g i v e n d i s t a n c e s f r o m
the s t a t i o n of m a r k i n g in 1968 . . .r ,

, . ,

N u m b e r of r e c a p t u r e s a nd e x p e c t e d f r e q u e n c i e s
of r e c a p t u r e s of b r o w n t r o u t fro m seven
s t a t i o n s in the Pine R i v e r s tud y area
d u r i n g 1968
. . . .
. . . . . . . .
C h i - s q u a r e g o o d n e s s of fit of o b s e r v e d
r e c a p t u r e s of b r o w n t r o u t to the nu mbe r
e x p e c t e d a s s u m i n g r e c a p t u r e s to be d i s ­
t r i b u t e d a c c o r d i n g to p o p u l a t i o n size in
seven sta t i o n s c o m p r i s i n g s e c t i o n B
d u r i n g 1968
........................

Page

Table
C h i - s q u a r e g o o d n e s s of fit of o b s e r v e d
nu mbers of r e c a p t u r e d b r o w n t r o u t to the
nu m b e r e x p e c t e d a s s u m i n g r e c a p t u r e s to be
d i s t r i b u t e d a c c o r d i n g to p o p u l a t i o n size
in 21, 2 0 0 - f o o t sta t i o n s a p p r o x i m a t e l y
one y ear a f t e r m a r k i n g ........... ........
10 .

11.

12

.

13 .

14 .

39

To tal n u m b e r and p e r c e n t a g e of b r o w n tr out
r e c a p t u r e s in 1969 (exclusive of their
first 1969 recapture) of fish m a r k e d in
1968, at v a r i o u s d i s t a n c e s f rom the p o i n t
of first c a p t u r e in 1969
............

41

T o t a l number, time out, an d p e r c e n t a g e of
b r o w n t r o u t r e c a p t u r e s m a d e at giv en
d i s t a n c e s from the s t a t i o n of m a r k i n g
d u r i n g 1969

42

T o t a l n u m b e r and p e r c e n t a g e of b r o w n tro ut
r e c a p t u r e d in 1969 at v a r i o u s d i s t a n c e s
f r om the p o i n t of first c a p t u r e in 1969

. . .

45

C h i - s q u a r e g o o d n e s s of fit of o b s e r v e d r e ­
ca ptu r e s of b r o w n trout to the n u m b e r
e x p e c t e d a s s u m i n g r e c a p t u r e s to be d i s ­
t r i b u t e d a c c o r d i n g to p o p u l a t i o n size in
21, 2 0 0 - f o o t s ta t i o n s d u r i n g 1969... ...........

46

E x p e c t e d and o b s e r v e d n u m b e r s of r e c a p t u r e s
m a d e at v a r i o u s d i s t a n c e s f rom the p o i n t
of in it i a l c a p t u r e d u r i n g 1969 . . . . . . . .

47

v

L I S T OF F I G U R E S
Fi gure

Page

1.

A m a p of the Pine R ive r stu dy ar ea

2.

P e r c e n t a g e d e v i a t i o n s of the o b s e r v e d from
the e x p e c t e d n u m b e r s of r e c a p t u r e s m a d e
at v a r i o u s d i s t a n c e s f r o m the p o i n t of
in itial c a p t u r e d u r i n g 1969

vi

. . . . . .

4

49

INTRODUCTION
M o v e m e n t s of fishes hav e r e c e i v e d m u c h a t t e n t i o n
since the e a r l y 1950's.

E f f o r t has b e e n d i r e c t e d t o w a r d

b o t h lotic and lentic e n v i r o n m e n t s ,
environment offers

sev e r a l

however,

adv ant age s.

the lotic

One a d v a n t a g e

is

that str e a m s c an be s a m p l e d r e l a t i v e l y e f f i c i e n t l y c o m p a r e d
to the d e e p e r p o r t i o n s of the
Also,

the a n a l y s i s of s t r e a m fish m o v e m e n t

since v e r t i c a l m o v e m e n t s
me nts

l a c u s t r i n e e n v i r onm ent .
is s i m p l ifi ed,

are l i m i t e d a nd h o r i z o n t a l m o v e ­

are p r i m a r i l y d i r e c t e d in o n l y t w o d i r e c t i o n s .
W h i l e m a n y o f th ese s t u d i e s h a v e i n d i c a t e d t h a t

m o v e m e n t by s t r e a m fishes

is q u i t e

limited,

li t t l e w o r k

has b e e n d o n e to d e t e r m i n e the i m p o r t a n c e of this p h e n o m ­
enon or w h a t

f actors are r e s p o n s i b l e .

G e r k i n g has p u b l i s h e d two re v i e w s

c o n c e r n i n g the

r e s t r i c t e d m o v e m e n t s of s t r e a m f i s h e s , and p r e s e n t s

the

p o s s i b i l i t y th at t e r r i t o r i a l b e h a v i o r or h i e r a r c h y m a y
have an e f f e c t on the d e g r e e of m o v e m e n t s h o w n by these
populations

(Gerking,

1953;

1959).

He p r e s e n t e d t hre e

po s t u l a t e s w i t h r e g a r d to t his p o s s i b i l i t y :
ra pid ly into an are a of u n d e r p o p u l a t i o n ,

(1)

fish m o v e

(2) a for eig n

p o p u l a t i o n w h e n p l a c e d in an e s t a b l i s h e d p o p u l a t i o n w i l l
be forced to m o v e out,

and

(3)

the e s t a b l i s h e d p o p u l a t i o n

2
wi ll m o v e a b o u t m o r e t han u s u a l as a r e s u l t of the c o m p e ­
tition.

It w o u l d s e e m fro m t h e s e p o s t u l a t e s t hat G e r k i n g

b e lieves

th at t e r r i t o r i a l i t y o p e r a t e s to r e g u l a t e d e n s i t y

by a l t e r i n g the d e g r e e of m o v e m e n t shown b y the p o p u l a t i o n ,
or at l eas t h e feels t hat d e n s i t y and m o v e m e n t are in some
way related.
If t her e is suc h a m e c h a n i s m o p e r a t i n g ,
functions in the m a n n e r s u g g e s t e d by Ge rk i n g ,
be p r o p o s e d t h a t if the p o p u l a t i o n
was reduced,
(1969),

a decrease

in an ar ea of s t r e a m

in an e x c e l l e n t s t u d y of the s o c i a l

si milar p os s i b i l i t y .

th en it m a y

in m o v e m e n t w o u l d ensue.

p o p u l a t i o n s of b r o w n trout,

and it

Jenkins

s t r u c t u r e of

S a l m o t r u t t a , has

indicated a

He s u g g e s t s th at the p r o p o r t i o n of

t r a n s i e n t fish in a p o p u l a t i o n m a y i n c r e a s e w i t h p o p u l a t i o n
density,
view,

pas t some t h r e s h o l d level.

a decrease

A c c o r d i n g to this

in d e n s i t y to a p o i n t b e l o w this t h r e s h o l d

level w o u l d re s u l t in d e c r e a s e d m o v e m e n t s of the p o p u l a ­
tion as a whole.
F r o m these

ideas,

a w o r k i n g h y p o t h e s i s m a y be

f o rmu la ted s uch tha t if the p o p u l a t i o n d e n s i t y of a t e r r i ­
torial s t r e a m fish was

red uced,

the d e g r e e of m o v e m e n t

shown by t hat p o p u l a t i o n w o u l d be r e d u c e d also,
factual e v i d e n c e to s u p p o r t this h y p o t h e s i s

Since

is lacking,

it

was d e c i d e d to a t t e m p t to d e t e r m i n e the e f f e c t of a d r a s t i c
de cre a s e in d e n s i t y o n the d e g r e e of m o v e m e n t sho wn by a
brown t rou t p o p u l a t i o n

in a small,

s o u t h e r n M i c h i g a n stream.

T HE S T U D Y A R E A
One of the p r o b l e m s

i n h e r e n t in stu d i e s of s t r e a m

fish m o v e m e n t is the p o s s i b i l i t y of fish m o v e m e n t b e y o n d
the limits of the s a m p l i n g area.

However/

c h o i c e of a

l o calized p o p u l a t i o n of s t r e a m fish w i t h w e l l - d e f i n e d
limits to its d i s t r i b u t i o n w o u l d ser ve to m i n i m i z e this
bias.

A short s e c t i o n of the Pine River in M o n t c a l m

County,

Mi chi g a n ,

just sou th of the

seemed to m e e t this r equ ire men t.

I s a b e l l a C o u n t y line,

The

area has b e e n f r e ­

qu ently st o c k e d w i t h small n u m b e r s of b r o w n trout and
ad jacent s e c t i o n s of the s t r e a m are c o n s i d e r e d as m a r g i n a l
ha bit at for this
1968,

species.

Se v e r a l sam ples

r e v e a l e d b r o w n and b r o o k trout,

f o n t i n a l i s , bo th in this

t a k e n in spring,

Salvelinus

are a and a s e c t i o n of the r i v e r

a p p r o x i m a t e l y six m i l e s upstream.

The a b u n d a n c e of b r o w n

trout in the u p s t r e a m are a w a s c o n s i d e r a b l y greater,
ever,

and the r i v e r w as

oughly sampled.

how­

s ma l l e r and c o u l d be m o r e t h o r ­

F o r the se r e a s o n s the u p s t r e a m a r e a w as

selected for study.
The u p s t r e a m are a ch o s e n for the s t u d y c o n s i s t e d
of the N o r t h B r a n c h u p s t r e a m to W e s t W a l t o n R o a d
The areas d o w n s t r e a m fr om the

(Fig.

1).

j u n c t i o n of the S out h B r a n c h

for several m i l e s a n d u p s t r e a m fro m W a l t o n Ro ad w e r e

Fig.

1.— A map of the Pine River study area.

5

Walton Road

Blanchard Road

Holland

Road

4-1

South branch Pine River

Pleasant Valley Road

Scale

6
c o n s i d e r e d u n i n h a b i t a b l e by trout,
s ummer m on t h s,

at l ea s t d u r i n g the

a nd s e v e r a l rod and re e l s a mples

e l e c t r o f i s h i n g s a mples
two b r o w n trout.

and t h r e e

t a k e n in these areas c o n t a i n e d o n l y

B o t h of t h es e w e r e t a k e n a short d i s t a n c e

b el o w the c o n f l u e n c e of the South B r a n c h d u r i n g August,
1969.
The s t r e a m b e t w e e n W a l t o n Road and its c o n f l u e n c e
w i th the S o u t h B r a n c h has an a v e r a g e g r a d i e n t of about
five feet per mile,

and a v e r a g e s ab o u t 25 feet in width.

Go od cov er is p r o v i d e d by s h o r e l i n e trees and s h r u b s ,
p r e d o m i n a n t l y wi llow,

S a l i x s p . , and alder, A l n u s

la tter f o r m i n g d e n s e t a n g l e s in some places.
places dense m ats of wa t e r c r e s s ,
p r o v i d e d e x c e l l e n t t r o u t cover,
qu ite scarce.
de epe r pools

s p . , the

In s e v e r a l

Nasturtium officinale,
a l t h o u g h these m a t s w e r e

F a l l e n trees ha ve p r o d u c e d some of the
in the study a r e a and m a n y b e n d h o l e s are

p r e s e n t a l o n g the ri v e r ' s m e a n d e r i n g course.
pool in the s tud y area a p p r o a c h e d o n l y four
d u r i n g no r m a l w a t e r

levels,

The d e e p e s t
feet in d e p t h

and cou ld be quite r e a d i l y

s a mpl ed w i t h the s t r e a m shocker.
study area is c o m p o s e d of silt,

The
sand,

s t r e a m b o t t o m in the
and gravel,

w i t h one

or a n o t h e r p r e d o m i n a t i n g in a n y gi ven s t r e a m s e c t i o n d e ­
p e n d i n g on the c u r r e n t veloc ity .

The s t r e a m b o t t o m as

well as its b a n k s r e m a i n e d q u i t e s t a b l e t h r o u g h o u t the
study e x c e p t for one p ool just b e l o w t he B r i n t o n Road
bridge.

This po ol b e g a n to fill w i t h sand in the s p r i n g

7
of 1969,

r e s u l t i n g in the e s t a b l i s h m e n t of a san d b a r in

the m i d d l e of the poo l by Septembe r.
change in the s t r e a m in 1969 w a s

Another noticeable

the d e c r e a s e

in size of

the few b eds of w a t e r c r e s s w h i c h h a d p r o v i d e d scarce but
good t rou t c o v e r in 1968.

T he r e a s o n s

for thi s d e c l i n e of

w a t e r c r e s s r e m a i n obscure.
V a r i o u s p a r a m e t e r s of s e l e c t e d c h e m i c a l q u a l i t i e s
of the w a t e r are i n c l u d e d in T a b l e
ta ken d u r i n g d a y l i g h t hours.

1.

A l l s amp l e s w e r e

These data indicate a rela­

ti v e l y h i g h b a s i c p r o d u c t i v i t y

for the s t u d y area.

Water

t e m p e r a t u r e s w e r e n o t c o n s i d e r e d l i m i t i n g to b r o w n trout,
as the h i g h e s t r e c o r d e d t e m p e r a t u r e w as
1968.

Strawn

(1958)

has

22. 0 ° C on J u l y 15,

l i s t e d 25 . 3 ° C as t h e u p p e r c r i t ­

ical l i m i t for b r o w n trout,

w h i l e the u p p e r i n s t a n t a n e o u s

lethal t e m p e r a t u r e has b e e n r e p o r t e d to be 27 - 2 9 ° C d u r i n g
the s u m m e r

( G r u d n i e w s k i , 1961).

Dissolved oxygen values

we re als o w i t h i n an a c c e p t a b l e range,
r e a d i n g of 5.4 m g / 1
1969,

w i t h the lo w e s t

r e c o r d e d at 8:30 p.m.

on S e p t e m b e r 5,

d u r i n g a r a t h e r p r o l o n g e d w a r m - w e a t h e r period.

Grudniewski

(1961)

has

r e p o r t e d m i n i m u m levels of d i s s o l v e d

ox y g e n for b r o w n t r o u t as b e t w e e n
the summer.

Do ubt les s,

t h e s e r e c o r d e d o b s e r v a t i o n s do not

e n c o m p a s s the full r a n g e of v a l u e s
the s t u d y area,

actually attained

in

b u t if m o r e e x t r e m e c o n d i t i o n s do exist,

th ey are p r o b a b l y s h o r t - l i v e d
currence.

2.5 an d 3.0 m g / 1 d u r i n g

Ove r a l l ,

conditions

anv." of r e l a t i v e l y rare o c ­
a p p e a r to be

favorable

for

Table 1.— Water chemistry of the Pine River at the Blanchard Road bridge,
Isabella County, Michigan, during 1968 and 1969,
(all concen­
trations expressed in ppm)

Sample size
Mean
Standard dev.
Range

Alkalinity*

D.O.

pH

Total
phosphate

28

29

26

30

31

Nitrate

184.8

9.3

—

0.158

0.465

17,1

2,2

—

0,083

0.211

0.0330.400

0.1250.750

142-228

6.3-14.1

7.2-8.8

*Only methyl orange alkalinity was recorded, as phenolphthalein alkalinity
was never observed.

9
s u r v i v a l of b r o w n t r o u t a n d it b e c a m e a p p a r e n t th at the
b r o w n t r o u t p o p u l a t i o n in this s e c t i o n of the r i v e r has
be en able to r e p r o d u c e and m a i n t a i n itself ov er an e x t e n d e d
pe r i o d of time w i t h o u t the nee d for s u p p l e m e n t a l

stocking.

M i c h i g a n D e p a r t m e n t of N a t u r a l R e s o u r c e s r e c o r d s
in dic a t e that the N o r t h B r a n c h was s t o c k e d w i t h a total of
13,000 b r o w n t rou t in 19 21 and 1924, w h i l e the Sou th B r a n c h
r e c e i v e d 41,500 b r o w n s

fr om 1926 to 1932.

The Sou th B r a n c h

a p p a r e n t l y no lo n g e r h o l d s trout d u r i n g the su m m e r months,
as an e l e c t r o f i s h i n g s a m p l e t a k e n t her e in Aug u s t ,
did not c o n t a i n a single trout.

P o n y Creek,

1969,

a sma ll t r i ­

bu t a r y e m p t y i n g in to the N o r t h Br a n c h b e t w e e n B l a n c h a r d
and W a l t o n Roads w as al so s t o c k e d w i t h a total of
br own trout b e t w e e n 1922 a nd 1926,
1968 w i t h rod and reel,

and one was c a u g h t in

so at lea st t here

that a few still persist.

Since

36,000

1932,

is a p o s s i b i l i t y

h owever,

no b r o w n

trout hav e be en s t o c k e d in this ar ea of the Pi ne River or
its wat ers hed .

D i r e c t e v i d e n c e of r e p r o d u c t i o n was o b ­

t a ine d in 1969,

w h e n a n u m b e r of y o u n g - o f - y e a r b r o w n t r o u t

were c o l l e c t e d in the s t u d y area.

A c h e c k w i t h the

M i c h i g a n D e p a r t m e n t of N a t u r a l R e s o u r c e s r e v e a l e d that no
b r own trout p l a n t i n g s h a d b e e n m a d e

in the s t r e a m system.

The p o p u l a t i o n in the s tudy a r e a can thus be c o n s i d e r e d as
a nat u r a l i z e d ,

e s t a b l i s h e d p o p u l a t i o n w h i c h has b e e n able

to m a i n t a i n its elf ove r an a p p r o x i m a t e l y 40 y ear period.

METHODS AND MATERIALS
D i v i s i o n of the S t u d y A r e a
The study area,

f rom a p o i n t 1,000

B r i n t o n Road b r i d g e u p s t r e a m
bridge,

for 3,200

was d i v i d e d into three,

c o m p r i s e d of seven,
st ati on was

feet b e l o w the

feet a bov e this

1 , 4 0 0 - f o o t sec tions,

2 0 0 — foot stations.

each

The end of e a c h

s i g n i f i e d by a s t r i p of w h i t e c l o t h tie d to a

n e a r b y twig, w h i l e the en d of a s e c t i o n w as d e n o t e d b y a
red cloth strip.

O c c a s i o n a l l y the p l a c e m e n t of these

m a r k e r s v a r i e d a few feet e i t h e r up o r d o w n s t r e a m .
instance,

if the e n d p o i n t of a s t a t i o n w a s

ce nte r of a pool,

the

For

l o c a t e d in the

flag w as a r b i t r a r i l y p l a c e d e i t h e r

at the he ad or tail of the pool,

as th ese

areas r e p r e s e n t e d

mo re d i s t i n c t d i v i s i o n s to the h u m a n o b s e r v e r an d p r e s u m ­
ably also to the fish.
or der as A, B,

The thr ee

sec t i o n s w ere d e n o t e d in

and C, w i t h C b e i n g the f u r t h e s t d o w n s t r e a m .

W i t h i n ea ch section,

the s t a t i o n s w e r e n u m b e r e d 1 t h r o u g h

7 c o n s e c u t i v e l y f rom d o w n s t r e a m to u pst ream.

T he le ngt h

of s t r e a m fr om the P l e a s a n t V a l l e y R oad b r i d g e to the
d o w n s t r e a m limit of s ec t i o n C w i l l be d e n o t e d h ere as area
D, w h i l e the le ngt h of s t r e a m fro m the u p s t r e a m l i m i t of
se ction A to the W a l t o n Ro ad br i d g e w i l l be t e r m e d a r e a E.

10

11
Fi sh S a m p l i n g
Br own t rou t w e r e c a p t u r e d w i t h a 115 V,

DC,

elec­

tric s t r e a m s h o c k e r in 1968 and the e a r l y p a r t of 1969,
after w h i c h ti me a 115 V, p u l s a t i n g AC un it wa s used.
B o th d e v i c e s w e r e s i m i l a r w i t h res p e c t to w a v e sh ape and
fr equ e n c y and a p p e a r e d to be e q u a l l y e f f i c i e n t

in practice.

An a u x i l i a r y u nit was al so e m p l o y e d d u r i n g the s tud y so
that v o l t a g e an d a m p e r a g e c o u l d be v a r i e d to suit the
v a r y i n g c o n d u c t i v i t y of the water.
and vo l t a g e to the point w h e r e
tured,

A r e d u c t i o n of a m p e r a g e

fish coul d still be c a p ­

but w h e r e the v i s i b l e e f f e c t s on the fish w e r e

m i n i m a l was attempted.

A s a t i s f a c t o r y c o m b i n a t i o n was

found to be 60 to 70 V,

a nd 0.7 to 1.0 amps,

c o m b i n a t i o n w a s used t h r o u g h o u t the study.
culty was e n c o u n t e r e d in c a p t u r i n g
ation,

but on ce captured,

w i t h i n a few m i n u t e s .

the

an d this
S ome d i f f i ­

fish w i t h this c o m b i n ­

fish u s u a l l y r e c o v e r e d

T wo n ota b l e e x c e p t i o n s o c c u r r e d

wh ere bro wn trout fai led to recover.

Bot h of t h e s e

fish

we re s u b j e c t e d to e x t r e m e l y long p er i o d s of sh ock when
they b e c a m e lodged in t hic k b r u s h and c o u l d n ot be q u i c k l y
netted.
No a s s u m p t i o n s w e r e m a d e on the e f f e c t of e l e c t r i c
shock on m o v e m e n t p a t t e r n s of s t r e a m fishes,
on this p oin t is lacking.

Although Gerking

as i n f o r m a t i o n
(1953)

made

some a ttempt to co m p a r e m o v e m e n t s of s h o c k e r - c a u g h t rock

12
bass, Ambloplit.es r u p e s t r i s , w i t h those of s e i n e - c a u g h t
fish,

he was n ot able to c a t c h e n o u g h fish w i t h the seine

to m a k e a v a l i d c omparison.
method,
bass,

s u g g e s t e d by E m b o d y

Fa j e n

(1962)

(1940),

u s e d the c r e s o l

to s a m p l e s m a l l m o u t h

M i c r o p t e r u s d o l o m i e u , a nd his res u l t s a p p r o x i m a t e d

those of e a r l i e r s t u d i e s of s m a l l m o u t h m o v e m e n t w h e r e
el e c t r i c shocke rs w e r e used.

Also,

cr e s o l has a d i s a d ­

v a n t a g e of t o x i c i t y and for t h e s e r e a s o n s t here app ear s
be l ittle a d v a n t a g e in u s i n g the cresol method.
fects of e l e c t r i c s hoc k on beh av i o r ,

stamina,

The e f ­

and m o r t a l i t y

rates of tr out ha ve b e e n s tu d i e d to some ex t e n t
Ball,

1966?

H o r a k an d Klein,

1967),

to

(Bouck and

w i t h the r e s u l t s i n d i ­

c a t i n g some a l t e r a t i o n of b e h a v i o r and a d e c r e a s e in
s tamina of s h o c k e d fish.

However,

no i n c r e a s e

in m o r t a l i t y

rates w e r e d e t e c t e d e v e n t h o u g h the sh ock g i v e n the
in each of these s t u d i e s was
Therefore,

fish

apparently quite s e v e r e .

since no p r a c t i c a l a l t e r n a t i v e m e t h o d is a v a i l ­

able for c a p t u r i n g large nu mb e r s of fish in streams,

it

was h o p e d that a r e d u c t i o n of a m p e r a g e an d v o l t a g e w o u l d
result in a c o r r e s p o n d i n g r e d u c t i o n in e f f e c t s on the fish.
After capture,

fish w e r e p l a c e d in a tub of s t r e a m

water, w h i c h w a s r e f i l l e d at the end of e ach station.
A f t e r s amp l i n g a station,
clipped,

e ach c a p t u r e d

fish was

or if it had p r e v i o u s l y r e c e i v e d a clip,

of clip was n o t e d and record ed;

finthe type

the t ota l l ength of the

fish was q u i c k l y m e a s u r e d and recorded;

and the fish was

13
released.

S e p a r a t e d a t a sheets w e r e u s e d for e a c h s t a t i o n

to av oid confusion.

M a x i m u m d i s t a n c e t h a t a fish c o u l d

have b e e n dis pla c e d ,

u s i n g this pro ced u r e ,

was

and this d i s t a n c e can be c o n s i d e r e d n e g l i g i b l e ,

200

feet

since

ho m i n g of b r o w n t r o u t has b e e n shown to o c c u r o ver m u c h
gr ea t e r d i s t a n c e s
The

(Schuck,

1945).

fish w e r e m a r k e d w i t h a m a x i m u m of tw o fin

clips c o n s i s t i n g of one m e d i a n and one p a i r e d fin,
some instances,

t wo m e d i a n fins

{Table 2).

or in

F in c l i p p i n g

was s e l e c t e d for m a r k i n g fish in p r e f e r e n c e to o t h e r m a r k ­
ing m e t h o d s b e c a u s e it is l o n g - l a s t i n g an d a p p a r e n t l y has
a m in i m a l e f f e c t on the fish as lo ng as no m o r e t han two
clips pe r fish are u s e d
1969;

(Nelson,

1960;

B r y n i l d s o n and B r y n i l d s o n , 1967;

Radcliffe,

1950).

S t a u f f e r and Hansen,
Shetter ,

1967;

T h e r e is a lso s ome e v i d e n c e th at fin

cl ipp i n g m ay not a l t e r the e x t e n t of fish m o v e m e n t
ing,

(Gerk­

1953) .
M a rk and r e c a p t u r e runs w e r e m a d e

weekly fro m J u l y t h r o u g h the
section B d u r i n g 1968,

approximately

first hal f of S e p t e m b e r in

a n d in all t h r e e d e l i n e a t e d

tions fr om June t h r o u g h Au gust,

1969.

T he m a r k a nd r e ­

capture p e r i o d e n c o m p a s s e d an 81 da y p e r i o d
an 80 da y p e r i o d in 196 9.

sec­

in 1968 and

The e n t i r e s t u d y area,

with

the e x c e p t i o n of th at p o r t i o n u p s t r e a m f r o m B l a n c h a r d
Road, was s a m p l e d on ce d u r i n g August,

19 68.

The area

above B l a n c h a r d Ro ad wa s s a m p l e d in part o n J u l y 1,

196 8.

14

Ta ble

2 . — T y p e s of f i n - c l i p s u s e d to m a r k b r o w n t r o u t
f r o m 21 sta t i o n s in the Pine Ri ver d u r i n g 1968
and 1969.
1968

St a t i o n

1969

Cl

—

anal—adipose

C2

—

upper caudal-adipose

C3

—

lo wer c a u d a l - a d i p o s e

C4

—

le ft p e c t o r a l — a dip ose

C5

—

right pelvic-adipose

C6

—

ri g h t p e c t o r a l - a d i p o s e

C7

—

lef t p e l v i c - a d i p o s e

B1

anal

anal

B2

u p p e r ca ud al

upper caudal

B3

l owe r ca uda l

l owe r ca uda l

B4

left p e c t o r a l

left p e c t o r a l

B5

r i g h t pel vic

right pelvic

B6

right pectoral

ri ght p e c t o r a l

B7

left p e l v i c

left p e l v i c

Al

—

anal-dorsal

A2

—

upper caudal-dorsal

A3

—

l o wer c a u d a l - d o r s a l

A4

—

left p e c t o r a l - d o r s a l

A5

—

right pelvic-dorsal

A6

—

r i g h t p e c t o r a l — dor sal

A7

—

left p e l v i c - d o r s a l

15
To tal n u m b e r s an d t ota l

lengths of all c a p t u r e d fish were

re co r d e d bu t no f i n - c l i p s w e r e given.

T h e c a p t u r e d fish

were r e l e a s e d p e r i o d i c a l l y d u r i n g s a m p l i n g o p e r ati ons .
Th ese same areas,

w i t h the i n c l u s i o n of the e n t i r e

of s t r e a m f rom B l a n c h a r d Roa d to W a l t o n Road,
of the S out h B r a n c h
from its mouth,
1969.

were

(area E)

and a p o r t i o n

for s e v e r a l h u n d r e d y a r d s u p s t r e a m
s a m p l e d in like m a n n e r d u r i n g August,

A ll b r o w n trout c a p t u r e d d o w n s t r e a m

upstream

fro m the thr ee

separate i d e n t i f y i n g clips.

study

These

(area D)

and

s e c t i o n s w e r e gi v e n

fish c o u l d th en be d i s ­

t i n g u i s h e d f r o m fish m a r k e d in the s t u d y sec t i o n s
idea of the ex t e n t of m o v e m e n t int o the
possible.

se cti on

and an

s t u d y s e c t i o n s was

A l t h o u g h two sa m p l e s w e r e t a k e n in the three

study s ect i o n s a fte r m a r k i n g t h e s e fish,

o n l y one m a r k e d

fish from are a D or E w a s recaptu red .
In a d d i t i o n to the d a t a c o l l e c t e d a nd m e n t i o n e d
above,

scale sam p l e s w e r e ta k e n fro m 97 b r o w n t r o u t c a p ­

tured in 1969 and 147 w h i t e

suckers,

s o n n i , t a k e n d u r i n g 1968 and 1969.

Catostomus commerS c a l e s w e r e t a k e n from

trout onl y d u r i n g the last s a m p l i n g p e r i o d b e c a u s e of the
p o s s i b i l i t y of i n f e c t i o n or b e h a v i o r a l a l t e r a t i o n s w h i c h
ma y have r e s u l t e d f r o m sk in d a m a g e a n d the a d d i t i o n a l
h a n d l i n g involved.
Tr o u t sc ale s w e r e t a k e n fro m an are a l o c a t e d i m m e ­
d i a t e l y b e l o w the l a t e r a l

line and just b e h i n d the tip of

the p e c t o r a l fin w h e n that fin w a s p r e s s e d b a c k a g a i n s t

16
the body, w h i l e s u c k e r sc ales w e r e t a k e n f r o m the r e g i o n
an ter ior to th e d o r s a l

fin and

just abo ve the lat e r a l

Sucker scales w e r e i m p r i n t e d on c l e a r p l a s t i c
examination,

but tr o u t scales,

for

b e c a u s e of t h e i r small size,

were m o u n t e d b e t w e e n two m i c r o s l i d e s .
48X was s u f f i c i e n t

slides

line.

A m a g n i f i c a t i o n of

for d e t e c t i o n o f a n n u l i in b o t h species,

and m e a s u r e m e n t of sca le r a d i u s

as w e l l as the d i s t a n c e

fr om the focus to e ach ann u l u s was
la teral m a r g i n u n d e r this

t a k e n at the a n t e r o ­

same m a g n i f i c a t i o n .

RESULTS
The F is h P o p u l a t i o n
The a b u n d a n c e of fish es c o m p r i s i n g e l e c t r o f i s h i n g
samples m a d e in the
196 8, a nd August,

study a r e a d u r i n g A u g u s t and September,

1969,

are shown in T a b l e

3.

B r o w n and

br ook trout w e r e the p r e d o m i n a n t s p o r t fis hes present,
a few small n o r t h e r n pike,
occasion.

Other

E s o x l u c i u s , w e r e t ake n on

fishes c o l l e c t e d in the s t u d y a r e a i n ­

cluded:

sto ner ol ler ,

lamprey,

Ichthyomyzon f o s s o r ; central mudminnow,

Campostoma anom a l u m ; northern brook

l i m i ; m o t t l e d sculpin,

s t o n e c a t , Not u r u s

gairdneri.

Umbra

Co t t u s b a i r d i i ; j o h n n y darter,

E t h e o s t o m a n i g r u m ; b l a c k sided d arter,

black bullhead,

flavus;

bluegill,

Percina macu l a t a ;

Lepomis m a c r o c h i r u s ;

I c t a l u r u s m e l a s ; a nd r a i n b o w trout,

Salmo

Th e l atter five spe c i e s wer e r e p r e s e n t e d in

the c o l l e c t i o n s by onl y one

s p e c i m e n eac h and sh o u l d be

c o n s i d e r e d as u n c o m m o n i nhab ita nts ,
other areas of the dra inage.
that the p e r c e n t a g e s

or as strays

from

F r o m T a b l e 3, it is a p p a r e n t

for the m o r e a b u n d a n t s p e c i e s in the

two 196 8 sam ple s are in clos e agreement.

The d i f f e r e n c e s

in abu nd a n c e of b o t h brown and b r o o k t r o u t in the two
samples

b ut

is p r o b a b l y a r e f l e c t i o n of the r e l a t i v e l y p o o r

17

18
T a bl e

3 . — A b u n d a n c e of fishes in e l e c t r i c s h o c k e r sa mpl es
t a k e n f rom the N o r t h B r a n c h of the P ine R ive r
d o w n s t r e a m fr om B r i n t o n Road d u r i n g A u g u s t , 1968
a n d 1969 ( A ) , and a s a m p l e t a k e n u p s t r e a m f r o m
B r i n t o n Ro ad d u r i n g Septembe r, 1968 (B).
(num­
be rs in p a r e n t h e s e s are percen tag es)

Species
w h i t e sucker
(Catostomus
commersoni)

1968

(B)

1968

(A)

1969

(A)

105

(50.2)

104

(48.4)

16

(10.7)

cr eek chub
(Semotilus
atromaculatus)

39

(18.7)

28

(13.0)

29

(19.5)

r i ver chub
(Hybopsis
micropogon)

12

(5.7)

14

(6.5)

32

(21.5)

9

(4.3)

12

(5.6)

7

b r ow n trout
(Salmo trutta)

16

(7.7)

27

(12.6)

22

(14.8)

common shiner
(Notropis
cornutus)

21

(10.0)

12

(5.6)

12

(8.1)

br ook trout
(Salvelinus
fontinalis)

3

(1.4)

13

(6.0)

27

(18.1)

rock bass
(Ambloplites
rupestris)

0

(0.0)

2

(0.9)

0

(0.0)

bl ack n o s e dace
(Rhinichthys
atratulus)

0

(0.0)

0

(0.0)

4

(2.7)

Others

4

(1.9)

3

(1.4)

0

(0.0)

ho g s u c k e r
(Hypentelium
nigricans)

Total

209

(99.9)*

215

(100.0)

149

(4.7)

(100.1)*

*Figures do n o t add to 100.0 b e c a u s e of r o u n d i n g errors.

19
trout h a b i t a t

found for so me d i s t a n c e abo ve the B r i n t o n

Road bridge.

The a g r e e m e n t o f the p a t t e r n s of p e r c e n t a g e

values

for the two 1968

sa m p l e s i n d i c a t e s

little c h a n g e

in

re lative s pe c i e s c o m p o s i t i o n d u r i n g the summer.
T h e s e data,
gross c h a n g e s

a l t h o u g h ca p a b l e of i n d i c a t i n g o n l y

in fish p o p u l a t i o n s ,

do s e e m to sho w a

d e c i d e d in cr e a s e in the a b u n d a n c e of r i v e r chubs

and b r o o k

trout in 1969 an d a d e c l i n e in a b u n d a n c e of w h i t e suckers.
Care sh o u l d be e x e r c i s e d in i n t e r p r e t i n g d a t a b a s e d on
e l e c t r o f i s h i n g samples,
selecti ve for l arger

ho wever,

fish.

sin ce the s ho c k e r is

Thus the r e s u l t s m a y r e f l e c t

no t only a b u n d a n c e o f the fish but als o r e l a t i v e sizes of
the fish.
Since the a v e r a g e
the 1969 sample was

19.6 c m in t otal

less than the ave r a g e of
sample,

size of w h i t e

su ckers c o m p r i s i n g

length,

o n l y 2.4 cm

22.0 c m o b t a i n e d fr om th e 1968

it w o u l d see m t hat the b ias r e s u l t i n g f rom the

size s e l e c t i v i t y of the e l e c t r i c s h o c k e r was neg lig ibl e.
However,

if o nly the

la rger s u c k e r s h a d d e c l i n e d in a b u n d ­

ance w h i l e the n u m b e r of y o u n g - o f - y e a r h ad increased,

an

ap parent d e c r e a s e in a b u n d a n c e could result.
For exa mple,
suckers was

s u p p o s e the p o p u l a t i o n of larger

100 in 1968,

year fish was

also 100.

and the p o p u l a t i o n of y o u n g - o f In 1969 the n u m b e r of fish in

each of these size c l a s s e s w as

50 and 200 r e s p e c t i v e l y .

Now assume u n e q u a l c a p t u r e rates

for the two size groups:

20
50% for the la r g e r fish and 10% for th e y o u n g - o f - y e a r .
A p p l y i n g t hes e c a p t u r e rates

to the p r o p o s e d p o p u l a t i o n s

in the two y e a r s we h a v e :
1968
Large fish
young—of-year

1969

100 X 0.5 =
100 X 0 . 1 =
N = 200

50
10

50 X 0.5 = 25
200 X 0.1 = 20

n = 60

N = 250

n - 45

It can be seen th at a l t h o u g h the t o t a l p o p u l a t i o n in 1969
was g r e a t e r th an in 1968,

the total n u m b e r of

fish in each

of the sa mp l e s i n d i c a t e s a d e c r e a s e d p o p u l a t i o n

in 1969.

A s i m i l a r s i t u a t i o n to the above a p p a r e n t l y e x i s t e d
in the st udy are a in 1968 and 1969.
wh i t e su ckers o f v a r i o u s
d u r i n g 1969 w e r e
than 19 c m at the
a ssumed that

S inc e no ne of the

ages c a p t u r e d in the s t u d y a r e a

found to h a v e a t t a i n e d le n g t h s g r e a t e r
f o r m a t i o n of the f irst an nulus,

fish un d e r this

sam p l e s of w h i t e

suckers c a p t u r e d in the stu dy ar ea d u r i n g 1968
found that 26% of the Au gust,

c o n s i d e r e d to be y o u n g - o f - y e a r ,

1968,

while

ple we re c o n s i d e r e d y o u n g - o f - y e a r .

and 1969,

sa m p l e w e r e

44% of the 1969 s a m ­

T hus

an i n c r e a s e in

the number of y o u n g - o f - y e a r a n d a d e c r e a s e
of o lde r w h i t e s u c k e r s

it was

length were young-of-year.

W h en this a s s u m p t i o n wa s a p p l i e d to the

it was

78

in the n u m b e r

in the st udy area is indicated.

i n c r e a s e d n u m b e r of y o u n g - o f - y e a r w e r e o b s e r v e d w hil e
sa mpling the st udy ar ea in 19 69 as c o m p a r e d to o b s e r v a ­
tions ma de d u r i n g 1968.

An

21
The e x a m p l e g i v e n a b o v e a p p a r e n t l y does n ot a p p l y
in the case of b r o o k t r o u t „
1968 and 1969

S i n c e the m e a n

l eng t h s of the

sam p l e s w e r e 20.8 and 17.5 c m r e s p e c t i v e l y ,

a bias r e s u l t i n g

fr om size s e l e c t i v i t y of the s h o c k e r

w o u l d hav e t e n d e d to s h o w a d e c r e a s e in a b u n d a n c e of b r o o k
trout in the 19 6 9 sample.

To the co ntr a r y ,

h owe v e r ,

the

n u mbe r of b r o o k t r o u t c a p t u r e d in 1969 s h o w e d a s u b s t a n t i a l
i n cr e a s e ove r the n u m b e r c a p t u r e d in 1968,
in crease in a b u n d a n c e
In summary,

in 1969.

o n l y l i m i t e d i n f o r m a t i o n is a v a i l a b l e

concerning population changes
p e r i o d of study.

i n d i c a t i n g an

in the s t u d y are a ov er the

L i m i t a t i o n s w e r e p r i m a r i l y due to s e ­

l e cti v i t y of the s h o c k e r
ti ca l i t y of u s i n g o t h e r

for l a r g e r fish and the i m p r a c fish s a m p l i n g d e v i c e s in a

r e l a t i v e l y f a s t - f l o w i n g stream.
po ss i b l e f l u c t u a t i o n s
year stu dy period.

in the

We can,

how e v e r ,

indicate

fish p o p u l a t i o n ov er the two-

The r e l a t i v e

spe c i e s c o m p o s i t i o n of

the st u d y area is f a i r l y s tab le d u r i n g the summer,

as

i n dic a t e d by the clo se a g r e e m e n t of the p a t t e r n s of v a l u e s
o b t a i n e d fro m the two 1968 samples.
river chubs
1969.

Bot h b r o o k t r o u t and

s howed an a p p a r e n t i n c r e a s e

The p o p u l a t i o n of l ar g e r w h i t e

re duc ed in 1969,
likely increased.

in a b u n d a n c e in

suc k e r s w a s p r o b a b l y

a l t h o u g h the n u m b e r of y o u n g - o f - y e a r m o s t
No c h a n g e in a b u n d a n c e of b r o w n tro ut

is i n d i c a t e d in 1969,

although strong evidence

for a d e ­

cr eas e in a b u n d a n c e wil l be d i s c u s s e d in the f o l l o w i n g
s e cti on of this paper.

22
T he B r o w n T r o u t P o p u l a t i o n
P o p u l a t i o n D e n s i t y .— The n u m b e r of b r o w n t r o u t
ov er 6- inc h e s in total

l e n g t h d e c l i n e d m a r k e d l y in the

st udy are a f rom 1968 to 1969.

Th e

fish p o p u l a t i o n d a t a

a l r e a d y d i s c u s s e d gav e no c l e a r i n d i c a t i o n of this dec lin e,
but a m o r e r e f i n e d e s t i m a t e

is a p p r o p r i a t e here.

T ota ls

of 64 and 29 b r o w n t r o u t r e s p e c t i v e l y w e r e m a r k e d in s e c ­
tion B in 196 8 a nd 1969, w h i l e the n u m b e r s of r e c a p t u r e s
m a de w e r e

105 and 36 r e s p e c t i v e l y . ^

W h e n the S c h n a b e l

m u l t i p l e m a r k and r e c a p t u r e m o d e l w as a p p l i e d to these
data,

e s t i mat es

of 68 and 31 w e r e o bta ine d.

Thu s

a 54.4%

n u m e r i c a l r e d u c t i o n in the n u m b e r of b r o w n t r o u t o v e r 6inches in len gth is indicated.
Sc hna bel e s t i m a t e s
year i n d i c a t e s

Th e a g r e e m e n t of the

w i t h the n u m b e r s of fish m a r k e d in each

that o v e r 90% of the fish

in the

study area

w e r e c a p t u r e d at least once d u r i n g the co u r s e of sampling.
The

f ormula used to o b t a i n the se e s t i m a t e s
k
N =

Z

i=l
w h e r e ni = the

k
(n.M.)/[( E x . )
1 1
i=l 1

to ok the

form:

+1]

total n u m b e r c a p t u r e d on the

ith day,

= the n u m b e r of m a r k e d fish in the p o p u l a t i o n
on the
ith day (prior to s a m p l i n g on that
day) ,

Ta ble s s h o w i n g the n u m b e r s of fish m a r k e d and
r e c a p t u r e s m a d e in each s t a t i o n of e a c h s e c t i o n and in
each yea r can be found in the appendix.

23
x-

= the n u m b e r of m a r k e d f ish c a p t u r e d on the
ith
day,

and N = the e s t i m a t e of the p o p u l a t i o n
This m o d e l a s s u m e s the followin g:
t her e

size.

(1) t h e r e is no

loss of marks,

(2)

is e q u a l m o r t a l i t y of m a r k e d and

u n m a r k e d fish,

(3) c a t c h a b i l i t y of m a r k e d and u n m a r k e d

fish does not d i f f e r and r e m a i n s the same,

and

(4)

there

is no r e c r u i t m e n t into the p o p u l a t i o n or e m i g r a t i o n of
ma r k e d fish fro m the po p u l a t i o n .
Sh et t e r

(1952),

ifiable as m a r k s

M a n y studies,

ha ve shown tha t c l i p p e d
for s e v e r a l years.

su mption can be accepted,

since

1966;

H o r a k and Klein,

fins r e m a i n i d e n t ­

T h u s the f i r s t a s ­

f i n - c l i p s w e r e the ty pe of

mark use d in the p r e s e n t study.
Ball,

notably

O t h e r s tud i e s

1967)

h ave

(Bouck and

sho wn no a d d i t i o n a l

m o r t a l i t y as a r esult of s h o c k i n g fish w i t h DC shockers,
and Ne l s o n

(1960),

S t a u f f e r and H a n s e n

ni l d s o n and B r y n i l d s o n

(1967),

(1969),

a m o n g others,

and Bry-

h a v e sh o w n

that the loss of up to t wo fins doe s no t d e c r e a s e
in trout.

T he ref ore ,

survival

the s e c o n d a s s u m p t i o n can be a c c e p t e d

for the p r e s e n t study.

Assumption three

is o p e n to a g o o d

deal of c r i t i c i s m and the v a l i d i t y of a s s u m p t i o n f our is,
of course,

the c o n c e r n of this

study.

T h e d e g r e e of s p a t ­

ial s t a b i l i t y thus far s h o w n for s t r e a m p o p u l a t i o n s of
brown t rou t

(Schuck,

1945;

Allen,

1951),

and the s t a b i l i t y

found for the p o p u l a t i o n in the p r e s e n t study,
dicate a c o m p l e t e v a l i d a t i o n of this

do n ot i n ­

f o u r t h a s s u m pt ion .

24
If this a s s u m p t i o n is false,

the p o p u l a t i o n e s t i m a t e s

would be b i a s e d up w a r d to the sa me d e g r e e in b o t h years,
and the r e l a t i v e d i f f e r e n c e w o u l d r e m a i n a p p r o x i m a t e l y the
same,

a s s u m i n g the same d e g r e e of e m i g r a t i o n and i m m i g r a ­

tion in bot h years.

This

last a s s u m p t i o n t h e n as sum es

that d e n s i t y has no e f f e c t on the d e g r e e of m o v e m e n t of
the trout, which,
in this study.
estimates,

of course,

is the h y p o t h e s i s b e i n g te s t e d

For p u r p o s e s of c o m p a r i n g the p o p u l a t i o n

h owever,

we w i l l a c c e p t the a s s u m p t i o n that

e m i g r a t i o n and i m m i g r a t i o n d i d n o t v a r y b e t w e e n years.
C o o p e r and L a g l e r

(1956)

h ave p o i n t e d out also

that p o p u l a t i o n e s t i m a t e s of this type are b i a s e d d o w n w a r d
w h en all length g ro u p s are p o o l e d b e f o r e e s t i m ati on.
While this bias

ca n n o t be c o m p l e t e l y el i m i n a t e d ,

p r opose th at i n d i v i d u a l e s t i m a t e s be m a d e
groupings

and the r e s u l t s pooled.

size gro up i n g s

they

for v a r i o u s

However,

size

the n u m b e r of

into w h i c h m a r k - a n d - r e c a p t u r e d a t a can be

br oken is li mit ed b y the nu m b e r s of fish of e ach size
group p res e n t a n d the n u m b e r of r e c a p t u r e s made.
pr e s e n t study,
small,

the n u m b e r of

In the

fish p r e s e n t in the are a was

and the a m o u n t of d a t a di d not w a r r a n t a b r e a k u p

into size groups.
fish un der 6- inches

However,

it w a s

felt t hat e x c l u s i o n of

in l e n g t h r e m o v e d a s u b s t a n t i a l p o r ­

tion of the bias r e s u l t i n g fr om p o o l i n g r
found th at r e c a p t u r e rates

Schuck

for b r o w n t r o u t o ver

(1945)
6- inches

25
in length w e r e v e r y n e a r l y the same b ut that r e c a p t u r e
rates

for s m a l l e r

fish d e c r e a s e d d r a s t i c a l l y w i t h size.

A d d i t i o n a l e v i d e n c e of a d e c r e a s e in a b u n d a n c e was
the rec apt ure in 1969 of o n l y 24 of the 64 b r o w n trout
ma r k e d in 1968.

A s s u m i n g a c o m p l e t e r e c a p t u r e of all

ma r k e d fish still p r e s e n t in the stream,

this r e p r e s e n t s a

m o r t a l i t y of 62.5% of the b r o w n tr out ove r 6-i nch es in
length.

This m o r t a l i t y e s t i m a t e is w e l l w i t h i n the range

of m o r t a l i t i e s
brown trout.

so far r e p o r t e d for s t r e a m p o p u l a t i o n s of
M c F a d d e n and C o o p e r

(1962),

of six s t r e a m b r o w n t rou t p o p u l a t i o n s ,
m o r t a l i t y rates

f rom 44.6%

fi s h i n g w as

brown tro ut ove r 6-inches was

1963), w hil e

allowed.

Their

like that of the p r e s e n t study,

were b a s e d o nly on age c la s s e s

in one W i s c o n s i n s t r e a m

r e p o r t e d an n u a l

for a s t r e a m c l o s e d to fishing

to 81.1% for a s t r e a m w h e r e
es tim ate s of m o r t a l i t y ,

in a c o m p a r i s o n

I t h r o u g h IV.
78% over one

(Brynildson,

a nnual m o r t a l i t y

M o r t a l i t y of

f i s h i n g sea son

Hacker,

and Klick,

(including e migration)

age II b row n t rou t in the Hin ds River,

N e w Zealand,

aged 82% t h r o u g h o u t t hei r lives

1964).

(Lane,

of
aver­

The 62.5% m o r t a l i t y e s t i m a t e r e p o r t e d in this
paper c l o s e l y a p p r o x i m a t e s the e s t i m a t e of the r e d u c t i o n
in num bers of t rou t o v e r 6- in c h e s
from m a r k - a n d - r e c a p t u r e d a t a

in t ota l

(54.4%)

l ength o b t a i n e d

and i n d i c a t e s

r e cru itm ent into the p o p u l a t i o n ov er 6- in c h e s
from 1968 to 1969.

little

in length

R e c r u i t m e n t into the size class o v e r

26
6-inches

in length in 1969 w o u l d come m a i n l y

ye ar class as i n d i c a t e d

in T a b l e

4.

f rom the

In fact/

1968

the p r o b a ­

bility of l o w r e c r u i t m e n t into the 6 -inch and g r e a t e r size
class in 1969 is s u p p o r t e d by the p r e s e n c e of o n l y one
y o u n g - o f - y e a r b r o w n t r o u t in the 1968
to the 82 c a p t u r e d in 1969.

Also,

sam p l e s as o p p o s e d

o n l y 15.9% of the e s ­

t i mated 1969 p o p u l a t i o n of b r o w n tr out o v e r 6 - i n c h e s
length wer e c o n s i d e r e d to be f r o m the

1968 y e a r class.

This 15.9% e s t i m a t e of the p r o p o r t i o n of y e a r l i n g s
1969 p o p u l a t i o n r e p r e s e n t s

in

in the

6.8% of the 1968 pop u l a t i o n ,

and by s u b t r a c t i n g this r e c r u i t m e n t e s t i m a t e f rom the
62.5% e s t i m a t e d m o r t a l i t y ,

a 55.7% r e d u c t i o n

is indicat ed;

a ve ry c l o s e a g r e e m e n t w i t h the p r e v i o u s e s t i m a t e of
o b t a i n e d by c o m p a r i s o n of p o p u l a t i o n e s t i m a t e s
two years.

It is appare nt,

then,

54.4%

f r o m the

that the r e d u c t i o n in

numbers of b r o w n tr o u t o v e r 6-i n c h e s

in tot al

le n g t h e x ­

c eeded 50% f r o m 1968 to 1969.
A g e and Size S t r u c t u r e .— A g e an d g r o w t h d a t a o b ­
t ained fro m 9 7 b r o w n t r o u t t a k e n in the s t u d y a r e a d u r i n g
August,

1969, are s how n in T a b l e

ti on s h i p used

4,

The body-scale rela­

to o b t a i n the m e a n c a l c u l a t e d l e n g t h s of

fish at e ach a nnulus t o o k the form:
Y = 2.5078 + 0.5 240 X
wh e r e
and

Y = t ota l l e n g t h o f the
X — scale rad i u s

fish in cm,

in m m x 48.

the

Table 4.— Age and growth of 97 brown trout taken from the Pine River study area
on August 11 and 25, 1969.
{means, standard deviations, and ranges
in total length are given in that order; all lengths are in
centimeters)
Year
class

Age
class

Average calculated length at annulus
2
3
4
1

Length at
capture

N

1968

I

10

19.3
1.96
16.3-22.9

11.0
1.42
8,8-13.4

1967

II

30

27.8
3.32
20.0-32.6

10.7
1.48
7.9-13.6

20.6
2.68
15.2-26.6

1966

III

55

36.6
3.11
29.8-43,8

11.0
1.77
7.5-14.9

22.1
2.99
16.8-30.6

30.8
3.03
24.0-38.0

1965

IV

2

44.2
2.97
42.1-46.3

13.4
0.14
13.3-13.5

26.7
2.83
24.7-28.7

35.8
3.11
33.6-38.0

40.9
2.00
38.3-43.5

Grand average
length

10.9
1.66
7.5-14.9

21.7
3.04
15,2-30,6

31.0
3.15
24,0-38.0

40,9
2.00
38.3-43.5

Number of fish

97

87

57

Average increment

10.9

10 e7

8.7

5.1

Summed increments

10.9

21.6

30.3

35.4

2

28
An a p p r o x i m a t i o n of the p r o p o r t i o n a t e age s t r u c t u r e
in b o t h 1968 and 1969 can be c o n s t r u c t e d by u t i l i z i n g the
g rowth h i s t o r i e s o f the v a r i o u s y e a r classes.

Assuming a

si x-m ont h g r o w t h p e r i o d an d l i n e a r i t y of g r o w t h
t hro ugh September,
March,

a nd no g r o w t h

from A p r i l

from October through

the m e a n l ength and a p p r o x i m a t e r a n g e in length

for

a given age class c a n be e s t i m a t e d by bac k c a l c u l a t i o n to
any pr ev i o u s m o n t h in the life of a fish.

The a s s u m e d

s i x - m o n t h g r o w i n g p e r i o d a ppe a r s to be a r e a s o n a b l e a p ­
pr o x i m a t i o n in light of the
and Jones

(1962)

i n f o r m a t i o n availab le.

Graham

r e p o r t e d that b r o w n t rou t in L l y n n T e g i d ,

W a l e s , gre w m o s t r a p i d l y f r o m Jun e to A u g u s t or S e p t e m b e r
and showed little or no g r o w t h f r o m N o v e m b e r to March.
Welsh rivers,

the p e r i o d of r a p i d g r o w t h was

April to A u g u s t or S e p t e m b e r

(Thomas,

Cooper

(1960)

f r o m M a r c h or

1964)„

perhaps m o r e a p p r o p r i a t e to the p r e s e n t

In

study,

In a paper
B e y e r l e and

r e p o r t e d tha t b r o w n t r o u t in P e n n s y l v a n i a

streams o b t a i n e d ha lf of t h e i r a n n u a l g r o w t h b e t w e e n m i d April and m i d - J u n e , w i t h a c e s s a t i o n of gro wth
ber thr o u g h March.

f rom D e c e m ­

W h i l e a s i x - m o n t h g r o w i n g se a s o n m a y

be a r e a s o n a b l e a s s u m p t i o n in the p r e s e n t study,

a less

r e aso nab le a s s u m p t i o n is tha t of l i n e a r i t y of g r o w t h d u r ­
ing this time,

since g r o w t h appears

to be g r e a t e r in the

sp ring than d u r i n g the res t of the g r o w i n g season,.
spite of this a p p a r e n t error,
appear to be fairly accurate.

In

the r e s u l t i n g a p p r o x i m a t i o n s

29
Th e r e s u l t s of t h e s e h a c k c a l c u l a t i o n s to the
lengths o f the v a r i o u s age c l a s s e s at p r e v i o u s
their

lives,

a n d the n u m b e r s

a nd p r o p o r t i o n s

fish e s t i m a t e d to be in e ach age c l a s s are
both

1968 and

1969

in T a b l e

5.

for e ach m o n t h are c a l c u l a t e d
month.

Th e

times in

of all m a r k e d

indicated

length ranges

for

shown

for the m i d p o i n t of each

As an i n d i c a t i o n o f the a c c u r a c y of t h e s e p r e ­

d i c t e d values,

th e

lengths

of the y o u n g - o f - y e a r

in 1969 can b e c o m p a r e d w i t h

the b a c k - c a l c u l a t e d

of the p r e v i o u s year c l a s s e s d u r i n g th eir
Sin c e an o v e r l a p in the
age groups

collected

length

first

lengths
summer.

frequency distributions

0 and I d i d not occur,

young-of-year brown

for
trout

could be c l e a r l y d i s t i n g u i s h e d

f r o m age X fish on the b a s i s

of length.

The range

in total

le ng th

b r o w n trout

collected

in the s t u d y ar e a d u r i n g the

of J u l y and the m o n t h of A ug ust,
w h i c h c o mp a r e s

1969,

was

last w e e k

6.0 - 10.7

cm,

f a v o r a b l y w i t h the p r e d i c t e d r a n g e of 6-6 -

10,0 c m for the m o n t h o f A u gust.
values

for 81 y o u n g - o f - y e a r

C o m p a r i s o n s of m e a n

in this c as e w o u l d b e o f l i t t l e v a l u e b e c a u s e o f the

strong s e l e c t i v i t y o f th e s h o c k e r

for larger s p e c i m e n s .

A p r o b l e m d e v e l o p e d in p l a c i n g
age groups,

since some o v e r l a p

fish in a p p r o p r i a t e

in p r e d i c t e d t ot a l

ranges o c c u r r e d b e t w e e n age gr oups.

Ho we v e r ,

fell w i t h i n t h e s e r an g es o f overlap,

a n d in t h e s e

the value r e p r e s e n t i n g th e t o t a l

length

f e w fish
cases,

l ength of the fish was

30

Ta b l e

5 . — E s t i m a t e s of the n u m b e r of m a r k e d b r o w n t r o u t in
e a ch age class, the p e r c e n t a g e of the p o p u l a t i o n
c o n t r i b u t e d by each age cl ass a n d the ra n g e s in
t o t a l le n g t h for ea ch age c las s for t h r e e m o n t h s
d u r i n g 1968 a nd 1969.
{all l en g t h s are in
centimeters)
A g e class

1968
0
Number

0

P e r c e n t of
population*

0

July

I

II

III

55

1

12 .5

85 .9

1.6

5. 1-7 .8

12 ,2- 2 1 . 2

21.0-34.9

3 6 ,3- 4 1 . 2

August

6.6-10.0

13.4-2 3.4

2 2.2 -36 .2

3 7 .1- 4 2 . 1

September

8 .1- 12. 3

1 4 . 6 - 25. 5

23.4-37.4

3 7.9 - 4 3 . 0

8

Length range

1969

A g e class
I

II

III

IV

Number

13

22

68

2

P e r c e n t of
population*

15. 9

20.7

61.0

2.4

June

13.3-19.1

18.1-30.2

2 7 . 5 — 41.5

40.6-45.2

July

14.8-21.0

19. 0-3 1.4

2 8 .6- 42. 6

41.3-45.7

August

16.3-22.9

20 .0- 3 2 . 6

2 9 .8- 4 3 . 8

42.1-46„3

L e n g t h ran ge

*The p o p u l a t i o n as he re d e f i n e d i n c l u d e s o n l y fish g r e a t e r
t h a n 6 ” in T.L.

31
lo c a t e d m o r e t o w a r d the c e n t e r o f the length f r e q u e n c y
d i s t r i b u t i o n of on e age g r o u p t han the other,
was p l a c e d in the

former age group.

For examp le,

upper l imi t of the tot al le n g t h r ang e of age
30.2 c m in June,
range of age

1969, w h i l e the

III fish was

the

II fish was

lower limit of the length

27.5 cm.

A fish 27.6 c m in total

length w as th en p l a c e d in age g r o u p II,
e red m ore

and the fish

as it was c o n s i d ­

l i k e l y t hat it wa s an age II fish than an age

III fish.
As ca n be seen f r o m T a b l e

5, the 1966 y e a r class

was d o m i n a n t in 1968, m a k i n g up a l m o s t
tion g r e a t e r t han 6 — inc hes

in total

86% of the p o p u l a ­

length.

d o m i n a n c e was c a r r i e d o v e r i nto 1969,

W h i l e this

th e r e l a t i v e s t r e n g t h

of the y e a r class h a d d e c l i n e d to 61% of the p o p u l a tio n.
The 1967 and 1968 y e a r c l a s s e s a p p e a r to be v e r y weak,

but

from the n u m b e r of y o u n g - o f - y e a r b row n tr o u t c o l l e c t e d in
1969,

a n o t h e r s t r o n g yea r class

ing.

This

ap pea rs

to be in the m a k ­

type of i n s t a b i l i t y has b e e n p r e v i o u s l y no t e d

in two s t r e a m p o p u l a t i o n s of b r o w n trout in N e w Z e a l a n d
(Burnet,

1959),

and a s u s p e c t e d cause was c a n n i b a l i s m b y a

do mi n a n t y e a r cl ass on y o u n g - o f - y e a r .

W h e n this d o m i n a n t

year class h ad d e c l i n e d to a low e n o u g h level,

it was

pr opo s e d that s u r v i v a l ra tes of y o u n g fish w o u l d a g a i n
increase to p r o d u c e a no t h e r d o m i n a n t y e a r class.
the cause,

this

Whatever

same p h e n o m e n o n a p p a r e n t l y al so oc c u r s in

the Pine River p o p u l a t i o n .

32
No five y e a r old b r o w n tr out w e r e c a p t u r e d in the
study a r e a d u r i n g 1968 or 1969 s a m p l i n g op e r a t i o n s .
fact,

In

tr out ove r four y e a r s of age w e r e q u i t e u n c o m m o n

(Table 5).

Th e g r o w t h rat es of b r o w n trout in the study

area w e r e b e t t e r than a v e r a g e
1969),

and this

for U.S.

streams

(Carlander,

is in a g r e e m e n t w i t h the p r o d u c t i v i t y d a t a

p r e s e n t e d for this

are a of the Pin e R i v e r and the n u t r i e n t

levels

(Table 1).

found t h e r e

M o v e m e n t a n d S t a b i l i t y .— D u r i n g 1968 an i n t e n s i v e
study of the m o v e m e n t s of b r o w n t r o u t w i t h i n
undertaken.

T h e n u m b e r s of

s e c t i o n B was

fish m a r k e d and r e c a p t u r e d in

each 2 0 0 - f o o t s t a t i o n on ea ch s a m p l i n g d a t e are s h o w n in
the A ppe ndix.

Th e m e a n time b e t w e e n i ni t i a l c a p t u r e and

re cap t u r e for the 10 6 r e c a p t u r e s co u l d n ot be a c c u r a t e l y
calculated because individual recognition became
as mo re and m o r e

impossible

fish w e r e a d d e d to the m a r k e d p o p u l a t i o n u

As an i n d i c a t i o n of the d e g r e e of s t a b i l i t y of the bro wn
trout p o p u l a t i o n ,

p e r c e n t a g e s of the total n u m b e r of r e ­

ca ptures ma de w i t h i n the ho me s t a t i o n and of r e c a p t u r e s
made e l s e w h e r e

in s ec t i o n B wer e c a l c u l a t e d

(Table 6 ) L

Home st a t i o n is here d e f i n e d as the st at i o n w h e r e
was o r i g i n a l l y c a p t u r e d a nd marked.

the fish

On ly a b o u t 3 3% of the

r e cap t u r e s m a d e in se c t i o n B o c c u r r e d o u t s i d e the home
stations.
ity,

To c h e c k the v a l i d i t y of this a p p a r e n t s t a b i l ­

a C h i - s q u a r e g o o d n e s s of fit test b a s e d on the p o p ­

ul a t i o n d e n s i t y of e ach s ta t i o n was ma de on the data™

33
This p r o c e d u r e has b e e n p r e v i o u s l y u s e d by G e r k i n g
to d e t e r m i n e

s t a b i l i t y in a s t r e a m p o p u l a t i o n of rock bass.

It was a s s u m e d that if the
th eir home

(1953)

stations,

fish sh owed no a t t a c h m e n t to

the d i s t r i b u t i o n of r e c a p t u r e s of

fish o u t s i d e t h e i r home

stations

s h o u l d be p r o p o r t i o n a l

to

the r e l a t i v e p r o p o r t i o n o f fis h m a r k e d in ea ch of the
various

stations.

This

a s s u m p t i o n t h e n r e c o g n i z e s tha t

some s t a t i o n s su p p l y b e t t e r h a b i t a t
since t he n u m b e r of fish m a r k e d

for trout than others,

in e a c h of the s t a t i o n s

va r i e d greatly.
Table 6. — T o t a l n u m b e r a n d p e r c e n t a g e of b r o w n tr out rec a p t u r e s m a d e at g i v e n d i s t a n c e s f r o m th e stati on of m a r k i n g in 1968.
Distance
1
2

0

in 2 0 0 - f o o t i n t e r v a l s
3
4
5

Number

71

20

11

2

2

0

Percent

67 .0

18.9

10.4

1.9

1,9

o
O

fre­

for each s t a t i o n as a f u n c t i o n of the n u m b e r of

fish m a r k e d in ea ch s t a t i o n
for each cell

(Table 7).

Expected values

in the table r e p r e s e n t the p r o d u c t of the

c o r r e s p o n d i n g r o w tot al

for o b s e r v e d and the p e r c e n t a g e

value

found at the b o t t o m of the c o r r e s p o n d i n g column.

Then,

s inc e the n u m b e r of trout c a p t u r e d on any o n e d a t e

o

for this a n a l y s i s w e r e o b ­

tained by f irs t c a l c u l a t i n g the e x p e c t e d r e c a p t u r e
qu encies

a

frequencies

0
D

Expected

6

Table 7.— Number of recaptures and expected frequencies of recaptures of
brown trout from seven stations in the Pine River study area
during 1968.
Marking
station

Station of recapture
3
4
5

1

2

1 observed
expected

10
1.75

4
5.47

0
0.66

0
1.09

0
1.97

0
0.22

0
2.84

14
14.00

2 observed
expected

7
6.12

41
19.14

1
2.30

0
3.83

0
6.89

0
0.76

0
9.95

49
48.99*

3 observed
expected

6
1.38

1
4.30

4
0.52

0
0.86

0
1.55

0
0.17

0
2.23

11
11.01*

4 observed
expected

0
0.50

0
1.56

0
0.19

3
0.31

1
0.56

0
0.06

0
0.81

4
3.99*

5 observed
expected

0
2.00

0
6.25

0
0.75

5
1.25

7
2.25

0
0,25

4
3.25

16
16.00

6 observed
expected

0
0.00

0
0.00

0
0,00

0
0.00

0
0,00

0
0,00

0
0.00

0
0.00

7 observed
expected

0
1.50

0
4.69

2
0,56

2
0.94

1
1.69

1
0.19

6
2,44

12
12.01*

13.25

41.41

4,98

8.28

14.91

1.G5

21,52

Percent of
total fish
marked
12.50

39.06

4 ,69

7.81

14.06

1.56

20.31

E exp.

♦Deviations are due to rounding errors.

6

7

Total

ZZ106.00

99,99*

35
was small and the e x p e c t e d v a l u e s

for some of these

tions on some d a t e s w e r e b e l o w 1.0,
pool the d a t a for e a c h s t a t i o n

sta­

it was n e c e s s a r y to

(Cochran,

1952),

The Chi-

s q uar e test was t h e n a p p l i e d to the se p o o l e d d a t a to c o m ­
pare the o b s e r v e d n u m b e r s of t r o u t r e c a p t u r e d at v a r i o u s
s tat i o n s d i s t a n t f r o m the s t a t i o n of i ni t i a l
ho me s t a t i o n
Table

(Table 8).

or

The p o o l i n g p r o c e s s c o n s i s t e d of

8 , — C h i - s q u a r e g o o d n e s s of fit of o b s e r v e d r e c a p ­
tu res of b r o w n t r o u t to the n u m b e r e x p e c t e d
a s s u m i n g r e c a p t u r e s to be d i s t r i b u t e d a c c o r d i n g
to p o p u l a t i o n size in s e v e n sta ti o n s c o m p r i s i n g
s e c t i o n B d u r i n g 1968.

0
Recaptures
observed

71

deviation

+4 4.59

X 2 = 112.47***
(.005,6)

D i s t a n c e in 2 0 0 -foot i n t e r v a l s
4
5
1
2
3

20

11

26 .41 21.49

expected

X2

capture,

-1.49

df =

2

14.73

16 .65

-3.73

-1 4.6 5

2

6

0

7. 52

0

14 .86

4 .34

- 5. 52 - 14.86

-4 .34

(K-l) ■ 7-1 = 6

= 18.50

a dding bo th the e x p e c t e d and o b s e r v e d v a l u e s in T a b l e 7
diagonally.

For e x a m p l e to o b t a i n the e x p e c t e d n u m b e r of

recaptures s h o w i n g no m o v e m e n t in T a b l e 8

(the v alu e

under the c o l u m n h e a d e d 0), w e w o u l d e n t e r T a b l e 7 at cell
1,1 and add all e x p e c t e d v a l u e s l y i n g on the d i a g o n a l
en d i n g at cell 7,7,

Th is p o o l i n g p r o c e d u r e m a y be s t a t e d

in terms of the formula:

36
F

= EF
ei

where F

eij

= the e x p e c t e d f r e q u e n c y of r e c a p t u r e s m a d e
ei
i s t a t i o n s d i s t a n t fr om the s t a t i o n of
m a r k i n g (from T a b l e 8 ),

and F

= the e x p e c t e d f r e q u e n c y of r e c a p t u r e s m a d e
i stations distant from station j , where
j is the s t a t i o n of m a r k i n g (from T a b l e 7).

e ij

T h e r e s u l t s of th is C h i - s q u a r e g o o d n e s s of fit
test are shown

in T a b l e

8.

The r e s u l t i n g C h i - s q u a r e value

of 112.47 was h i g h l y s i g n i f i c a n t
d i c a t i n g t hat the

(X

2

g = 18.50),

in­

fish d i d no t d i s t r i b u t e t h e i r m o v e m e n t s

over the v a r i o u s s t a t i o n s of s e c t i o n B in p r o p o r t i o n to
the p o p u l a t i o n d e n s i t i e s

of the s t a t i o n s , b u t t e n d e d to

spend m o s t of t h e i r time

in the v i c i n i t y of t h e i r h o m e

st ations o v e r the

81 d ays of the study.

It s h o u l d be m a d e c l e a r th at this p h a s e of the
study was n o t c o n c e r n e d w i t h m o v e m e n t of b r o w n tr out out
of the s a m p l i n g area,
tions of s e c t i o n B.

but only with movement between sta­
T h a t a p o r t i o n of the p o p u l a t i o n of

s t r e a m fishes m o v e s r a t h e r w i d e l y has b e e n s u g g e s t e d by
Funk

(1955),

and this m a y hav e b e e n the case d u r i n g the

196 8 p h a s e of the p r e s e n t study.

H owever,

one s a m p l e w as

taken fro m the P l e a s a n t V a l l e y R oad b r i d g e to the B l a n c h a r d
Road bridge,

about a h a l f m i l e u p s t r e a m f rom the a r e a of

in tensive study,
taken fr om the

d u r i n g 196 8.

While numerous

t r o u t were

j u n c t i o n of the South B r a n c h to the B l a n ­

chard Roa d bridge,

o n l y thr ee r e c a p t u r e s w e r e m a d e o u t s i d e

37
s ec t i o n B.

One of the se was m ade a b o u t 500 feet d o w n s t r e a m

fr om s t a t i o n B l , w h i l e two w e r e mad e w i t h i n
s t r e a m f rom s t a t i o n B 7 .

No t r o u t w e r e t a k e n b e l o w the

c o n f l u e n c e of the S o u t h Branch,
l ikely t hat any tro ut t r a v e l e d
Pl ans

2 5 feet u p ­

m a k i n g it e x t r e m e l y u n ­
f u r t h e r d o w n s tre am.

for the s t u d y o r i g i n a l l y i n c l u d e d a t h r e e ­

fold e x p a n s i o n of the s a m p l i n g are a a n d a d i v i s i o n of the
s a m p l i n g p e r i o d in 1969.

D u r i n g the fi rst period,

tition of the 1968 e x p e r i m e n t wa s to be attempted;
after a d e c i m a t i o n of the b r o w n t rou t po p u l a t i o n ,
s econd s a m p l i n g p e r i o d w o u l d begin.

a repe­
then,
the

Th is d e c i m a t i o n was

p l a n n e d to test the h y p o t h e s i s th at a d e c r e a s e

in d e n s i t y

w o u l d r e d u c e the d e g r e e of m o v e m e n t shown by the r e m a i n i n g
fish.

D u r i n g the first p h a s e of the 1969 study,

however,

it b e c a m e a p p a r e n t tha t the p o p u l a t i o n was

already sub­

s t a n t i a l l y r e d u c e d in n u m b e r

level,

f rom the 1968

a further r e d u c t i o n was n o t w a r r a n t e d .

a n d thus

The fi rst study

period wa s t hen l e n g t h e n e d to e n c o m p a s s an 8 0 day period,
a p p r o x i m a t e l y the same le n g t h of tim e as in 1968.
In 1969,

the a rea of i nt e n s e s t u d y was e n l a r g e d to

include se ct i o n s A and C, a nd in addit ion ,
taken from a reas D and E.
sa mp l i n g o per ati ons ,

one s a m p l e was

D u r i n g the c o u r s e of these

24 t rou t of the 64 m a r k e d in sec t i o n

B in 196 8 w e r e r e c a p t ure d.

The d i s t r i b u t i o n of t h e s e r e ­

captures was w i d e r than the d i s t r i b u t i o n of the

1968 r e ­

captures , h o w e v e r all w e r e taken w i t h i n the thr ee study

38
sections*

A p p a r e n t l y some r e d i s t r i b u t i o n h a d o c c u r r e d

b e t w e e n Septe mbe r,

1968,

and June,

1969*

T h i r t e e n of

these 24 tr out w e r e r e c a p t u r e d in s e c t i o n B and of these
13,

se ven

(54%)

w e r e t ake n in st ati o n s o t h e r th an their

1968 h ome station.

Th is p e r c e n t a g e

is c o n s i d e r a b l y g r e a t e r

than the 33% e s t i m a t e of m o v e m e n t away

fr om the h ome s t a ­

tion in s e c t i o n B d u r i n g the s u m m e r of

1968.

E l e v e n of

the 24 r e c a p t u r e d t r o u t ha d m o v e d into the a d j a c e n t s e c ­
tions A and C.
To d e t e r m i n e if the p o p u l a t i o n c oul d still be c o n ­
sidered to be o r i e n t e d a r o u n d the h o m e s t a t i o n s after
almost a ye ar of res ide n c e ,

a C h i - s q u a r e g o o d n e s s of fit

test was a p p l i e d to these f irs t 1969 r e c a p t u r e s of t r o u t
ma rke d in 1968.

The m e t h o d of o b t a i n i n g e x p e c t e d v a l u e s

was the same as for the p r e v i o u s

te st of the

196 8 data,

wi th the same a s s u m p t i o n tha t the d i s t r i b u t i o n of r e c a p ­
tures was p r o p o r t i o n a l to the r e l a t i v e d e n s i t i e s of t r o u t
in the 21 stations.

The r e s u l t s of this test, s h o w n in
2
Table 9, ind ic a t e a s i g n i f i c a n t X
v a l u e of 27.48
2
(X
^2 = 26.2).
Thus the t r o u t a p p e a r to ha ve r e ­
stricted their m o v e m e n t s o v e r the w i n t e r or at least
returne d to areas o c c u p i e d d u r i n g the p r e v i o u s
The m e a n d i s t a n c e m o v e d by th ese
1968 and 1969 was

608

summer.

2 4 trout between

feet, w i t h one t rout m o v i n g

2,400

feet upstream.

The n et shift show n by the s a m p l e was

feet upstream,

a n ot too s i g n i f i c a n t s h i f t w h e n it is

120

Table 9.— Chi-square goodness of fit of observed numbers of recaptured brown trout to
the number expected assuming recaptures to be distributed according to pop­
ulation size in 21, 200-foot stations approximately one year after marking.

0

1

2

3

Distance in 200-foot intervals
4
5
6
7
8

9

10

11

12+

Recaptures
1
0
observed
6
2
3
0
1
3
1
0
0
1
6
1.03
0 c90 1.38
1.43
2.37
1.90
2,59
2,17
2.03
2,52
1.32
expected
2.10
1.77
deviation +4.57 +3.63 -1.10 +0.10 +0.41 -2,17 -1.03 +0.48 -0,32 -1,77 -1.03 -0.90 -0.38

X 2 = 27.48**n.s,
X 2 (.05,12) - 21.0

df =

(K-1J = 13-1 = 12

40
r e m e m b e r e d t hat m o v e m e n t was o n l y e s t i m a t e d in 2 0 0 - f o o t
intervals.

T h e r e s e e m e d to be a p o s s i b l e t e n d e n c y for

ol d e r fish to m o v e to a g r e a t e r e x t e n t tha n the y o u n g e r ,
as 17 fish e s t i m a t e d to be in age g r o u p III in 1969 had
mo v e d an ave r a g e of 576

feet, w h i l e sev en

fish e s t i m a t e d

to be in age g r o u p II h a d m o v e d an a v e r a g e of o n l y 4 86
feet.

This

same p h e n o m e n o n has b e e n p r e v i o u s l y o b s e r v e d

in b r o w n trout
s t r e a m fishes

(Allen,

1951),

(Gerking,

1953),

found for s t r e a m fishes

and in var i o u s w a r m - w a t e r
b u t q u i t e the o p p o s i t e was

in M i s s o u r i

(Funk,

1955).

It is

s u f f i c i e n t to state he re tha t i n f o r m a t i o n is i n c o n c l u s i v e
on this p o i n t at p r e s e n t .
The s u b s e q u e n t m o v e m e n t s of th ese
r eco r d e d d u r i n g s a m p l i n g in 1969
recapture d a t a o n this
approximately
w ithin 400

(Table

2 4 t rou t w e r e

10).

Although

small n u m b e r of fish was

82% of the 33 r e c a p t u r e s made,

limited,

occurred

feet of the sta t i o n of first 1969 capture,

in dic ati ng that the p o p u l a t i o n was

still m a i n t a i n i n g a

relative sp atial stability.
D u r i n g 1969, m o v e m e n t of t rou t w i t h i n s e c t i o n B
was again studied.

The

wi thin s ections A and C,

same p r o c e d u r e s w e r e also u s e d
a l l o w i n g an e s t i m a t e

of m o v e m e n t b e t w e e n these c o n t i g u o u s

areas.

Because both

the low n u m b e r of t rou t and the 21 d i f f e r e n t
binations us ed m a d e

to be m a d e

fin-clip com­

it e x t r e m e l y u n l i k e l y that two fish of

the same size w o u l d r ec e i v e the same mark,

r e c o g n i t i o n of

41
individual

fish was p oss ibl e.

Th e r e f o r e ,

m e a n time out,

or the m e a n n u m b e r of days b e t w e e n in it i a l c a p t u r e and
recapture,

c o u l d be c a l c u l a t e d for the r e c a p t u r e s m a d e

in 1969.
Table 1 0 . -- Total n u m b e r an d p e r c e n t a g e of b r o w n t r o u t r e ­
c a p t u r e s in 1969 (exclusive of t h e i r first 1969
recapture) of fish m a r k e d in 1968, at v a r i o u s
d i s t a n c e s fro m the p o i n t of f irs t c a p t u r e in
1969.

0
Nu m b e r

18

Percent

54.5

Distance
1
2

in 2 0 0 - f o o t i n t e r v a l s
3
4
5
6
7

8-20

6

3

2

1

9.1

6.1

3.0

18.2

Me an time out,

2
6.1

0

1

0

0.0

3 .0

0.0

as we ll as the n u m b e r s

and p e r c e n t ­

ages of r e c a p t u r e s m a d e in the hom e s t a t i o n and e l s e w h e r e
in section B w e r e a g a i n ca l c u l a t e d ,

and the sam e c a l c u l a ­

tions w e r e p e r f o r m e d for the r e c a p t u r e s m a d e in sec t i o n s A
and C.

Recaptures displaying movement between sections

were not c o n s i d e r e d he re so that the r e s u l t s c o u l d be
co mpared to the 196 8 results.
cu lations

The res u l t s of t h e s e c a l ­

i ndi c a t e l ittle d i f f e r e n c e in the m o v e m e n t p a t ­

terns of the

fish e i t h e r b e t w e e n d i f f e r e n t s e c t i o n s or

be twe en years

(Table 11).

It is p o s s i b l e

that the re was

a change in the d e g r e e of l o n g - r a n g e m o v e m e n t b e t w e e n the
two years.

In o t h e r wor ds,

more

fish m a y ha ve m o v e d out

42

Ta ble 1 1 . — T o t a l nu mber, time out, a nd p e r c e n t a g e of
b r o w n t r o u t r e c a p t u r e s m a d e at g i v e n d i s t a n c e s
fr om the s t a t i o n of m a r k i n g d u r i n g 1969„
(stations w e r e 200 feet in length)
Se c t i o n A
0
Number

24

Percent

70 .6

Distance
1
5
14 .7

in 2 0 0 - foot i n t e r v a l s
4
5
2
3
4
11. 8

0

1

0

0

0 „0

2 ,9

0 „0

0.0

2 3.3 d a y s

M e a n time out
Se c t i o n B
0
Nu m b e r

27

Pe rce nt

73 .0

Distance
1
6
16.2

in 20 0 — foot in t e r v a l s
3
4
2
5

6

3

0

1

0

0

8 .1

0.0

2.7

0.0

0.0

Mean time out

27.4 d a y s

Se ction C
0
Nu mber

18

Pe rce nt

69 .2

Me an time out

6

Distance
1
3
11.5

in 2 0 0 - f o o t
2
3

intervals
5
4

2

2

1

0

0

7.7

7.7

3.8

0. 0

0.0

6

24 .9 d a y s

43
of the s tud y s e c t i o n s
If this w e r e true,

in one y e a r t h a n in the o t h e r year.

it w o u l d be e x p e c t e d that

fish w o u l d r e m a i n in the s e c t i o n s
ra te w o u l d be less in t hose
marked

fish was

and t hat the r e c a p t u r e

s e c t i o n s w h e r e e m i g r a t i o n of

the greatest.

The r e c a p t u r e rat es w i t h i n

the s e c t i o n of o r i g i n a l m a r k i n g w e r e

0.94,

for A, B, an d C r e s p e c t i v e l y in 1969;
B in 1968.

fewer m a r k e d

1.24,

and 1.64

a nd 1.37

for s e c t i o n

G i v e n t h a t the r e c a p t u r e r ate is n e g a t i v e l y

re l a t e d to m o v e m e n t of fis h o ut of the r e c a p t u r e area,

it

is p o s s i b l e to e x a m i n e the e f f e c t of d e n s i t y on the d e g r e e
of e m i g r a t i o n

f rom e a c h of th ese t h r e e s e c t i o n s in 1969.

Since the n u m b e r of

fish m a r k e d in 1969 d e c l i n e d

succes­

sively f rom s e c t i o n A to s e c t i o n C w h i l e the r e c a p t u r e
rate i n c r e a s e d in the same order,

it m i g h t be a s s u m e d that

the e m i g r a t i o n ra te i n c r e a s e s w i t h density.
rate of recapture,

ho wev e r ,

The h i g h e s t

o c c u r r e d in s e c t i o n B in 1968,

wh en the p o p u l a t i o n was at a pe ak and thus d o u b t is cast
on this a s s u m e d r e l a t i o n s h i p b e t w e e n d e n s i t y and e m i g r a t i o n
rate.

Also,

it is d o u b t f u l if the numbeis of fish m a r k e d

in each of the t hr ee s t u d y s e c t i o n s
'real*

d e n s i t y di f f e r e n c e ,

in 1969 r e f l e c t any

bu t m o r e l i k e l y r e f l e c t a d i f ­

ference in h a b i t a t q u a l i t y of the three sections.
data sug ges t

Th ese

l ittle ch a n g e in l o n g - d i s t a n c e m o v e m e n t s

of

brown tr out w i t h i n the s t u d y are a e v e n w i t h a d r a s t i c d e ­
crease in density.

44
Of the t ota l of 120 r e c a p t u r e s of the
ma rke d in 1969,
tional lines,
1,600

o n l y 24 d i s p l a y e d m o v e m e n t

made 2,600

across

an d o n l y one r e c a p t u r e was m a d e

feet f r o m the hom e station.
feet upstream.

8 4 fish

f arther

than

This one r e c a p t u r e was

The p e r c e n t a g e s a n d n u m b e r s of

these 120 r e c a p t u r e s m a d e at v a r i o u s d i s t a n c e s
home s ta t i o n are s how n in T abl e
goodness of fit t e s t was

sec­

12.

fro m the

Another Chi-square

a p p l i e d to t h e s e data,

done for the 196 8 r e c a p t u r e s in s e c t i o n B.

as was

The same

method of o b t a i n i n g e x p e c t e d va l u e s was used,

and the

assumption t h a t the d i s t r i b u t i o n of r e c a p t u r e s w a s p r o ­
portional to the r e l a t i v e d e n s i t i e s o f t r o u t in the 21
stations was

a g a i n tested.

R e l a t i v e d e n s i t i e s of

fish in

each sta t i o n w e r e ag ain b a s e d on the n u m b e r of t r o u t m a r k e d
in each station.

E x p e c t e d v a l u e s c an be o b t a i n e d by u t i l ­

izing the d a t a in the appendix.

The re s u l t s of this test

are inc lud ed in T a b l e 13.

The c a l c u l a t e d C h i - s q u a r e v a l u e
2
of 564.74 was h i g h l y s i g n i f i c a n t (X
qq^
= 28.3) , i n d i ­
cating that trout m o v e m e n t s — just as in 1 9 6 8 — wer e not
related to the d e n s i t y of t r o u t in the v a r i o u s st ations,
but we re o r i e n t e d a r o u n d the hom e station.
Table 14 shows
served at var i o u s

the num b e r s of r e c a p t u r e s o b ­

distances

f r o m the h ome

station,

as w e l l

as the e x p e c t e d n u m b e r s of r e c a p t u r e s at tho se d i s ­
tances.

In c a l c u l a t i n g the se e x p e c t e d values,

assumed that the

it was

fish had an e q u a l l i k e l i h o o d of m o v i n g

Table 1 2 0— Total number and percentage of brown trout recaptured in 1969 at various
distances from the point of first capture in 1969.

0
Number
Percent

69
57.5

2

1
18
15.0

10
8.3

Distance in 200-foot intervals
4
5
7
8
9
10
6

3
6
5=0

6
5.0

6

0
5.0

2
0.0

2
1.7

0

0

0

1.7

0.0

0.0

11

12

0

1

0.0

0.0

13

14-20
0

0.8

0.0

Table 13.— Chi-square goodness of fit of observed recaptures of brown trout to the number
expected assuming recaptures to be distributed according to population size in
21, 200-foot stations during 1969.

0

2

1

3

Distance in 200-foot intervals
4
5
6
7
8

9

10

11

12+

Recaptures
18
observed
69
10
0
0
0
6
6
0
2
2
0
1
18.37
6.57
6.16
expected
7.88
8.01
9.33
9.71
8.84
7.23
6=36
6.47
7.60 10.35
deviation +61.40 +7.65 +2.12 -2.01 -3.33 -9.71 -6.84 -5.23 -6.36 -6.47 -6.57 -6.16 -17.37

X 2 = 564,74***
X 2 (.005,12) = 28.3

df =

(K-l) - 13-1 = 12

Table 14.— Expected and observed numbers of recaptures made at various
distances from the point of initial capture during 1969.

Distance in
200-foot
intervals

Number of marked
fish which could
be recaptured

Probability of
recapture

Expected
recaptures

Observed
recaptures

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

43.5
43.5
43.5
43.5
43.5
43.5
43.5
43.5
43.5
43.5
43.5
40.5
35.5
30.0
27.5
24.0
21.0
16.0
12.0
9.0
5.5

0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0621
0.0588
0.0508
0.0428
0.0394
0.0343
0.0300
0.0229
0.0171
0.0129
0.0079

7.45
7.45
7.45
7.45
7.45
7.45
7.45
7.45
7.45
7.45
7.45
7.06
6.09
5.14
4.73
4.11
3.60
2,75
2.05
1.55
0.50

69
18
10
6
6
6
0
2
2
0
0
0
0
1
0
0
0
0
0
0
0

48
either up or d o w n s t r e a m ,

and th at the p o p u l a t i o n d e n s i t i e s

of the st ati o n s d id n o t a f f e c t t h e i r m o v e m e n t s .

A gr aph

of the d e v i a t i o n s b e t w e e n t hes e e x p e c t e d an d o b s e r v e d
values is s h o w n in Fig.

2.

Thi s g r a p h shows t h a t the r e ­

capture rate wa s m u c h g r e a t e r tha n e x p e c t e d up to 4 00 feet
from the ho me station ,

at w h i c h p o i n t the o b s e r v e d rate

de clined to less t han the e x p e c t e d rate,.
of the 120 r e c a p t u r e s w e r e m a d e w i t h i n
home station,

an d 96%

(115)

About

81%

(97)

400 feet of the

were made within

1000

feet.

These d ata agree r e a s o n a b l y w e l l w i t h those of A l l e n
(1951), w h o

found th at 92.5% of his r e c a p t u r e s of b r o w n

trout o c c u r r e d w i t h i n

450 f eet of the m a r k i n g site.

His

higher v a l u e c a n be at l e a s t p a r t i a l l y a t t r i b u t e d to the
small size of his s t a t i o n s

(900 feet as o p p o s e d to 4,200

feet in the p r e s e n t a n a l y s i s ) , w h e r e b y

fish m o v i n g d i s ­

tances g r e a t e r th an 900 feet di d n ot r e m a i n in the r e c a p ­
ture area,

an d c o u l d o n l y be i n c l u d e d in the a n a l y s i s

if

they m o v e d far e n o u g h to e n t e r a n o t h e r s a m p l i n g area.
Fr om this evidence,
the p r e s e n t study,

as w e l l

as f r o m the d a t a p r e s e n t e d

it can be p r o p o s e d t h a t the u s u a l m o v e ­

ments of the b r o w n tro ut e n c o m p a s s a b o u t 400 li n e a r
of stream, w i t h l o n g e r m o v e m e n t s
ionally.

Of course,

applicable,

in

feet

be i n g m a d e o n l y o c c a s ­

th ese v a l u e s m a y no t be g e n e r a l l y

as the p h y s i c a l

fe atu r e s of a p a r t i c u l a r s t r e a m

may temper the r ang e o f fish m o v e m e n t to a g r e a t extent.
Fish m o v i n g l onger d i s t a n c e s c an be p r e s u m e d to be in the

Fig. 2,— Percentage deviations of the observed from the expected numbers
of recaptures made at various distances from the point of
initial capture during 1969.

+900

+800

+700 ‘

Percent

deviation

+600

+500

+400 "

+300

+200

'

+100

"

-1 0 0

0

1

2

/

5

6

7

8

9

Distance in zuO-foot laterals

10

11

12

13

14+

51
pr ocess of e i t h e r c h a n g i n g t h e i r h o m e s i t e s or p e r h a p s

to

re pre sen t the m i g r a t o r y p o r t i o n of the p o p u l a t i o n s u g g e s t e d
by Funk.

(1955)

and J e n k i n s

(1969) .

DISCUSSION
A g r e a t a r r a y of l i t e r a t u r e on the m o v e m e n t of
stream fishes

is available.

A ll of these

s tud ies have

in dicated that s t r e a m f ishes t e n d to m a i n t a i n
spatial stability,

or a t e n d e n c y to re m a i n in a l i m i t e d

area for p e r i o d s of s e v e r a l w e e k s o r months.
19 3 6 there was

a relative

As e a r l y as

good i n f o r m a t i o n on the m o v e m e n t of b r o o k

trout that i n d i c a t e d a h i g h d e g r e e of spa t i a l s t a b i l i t y
(Shetter,
Allen

1936).

(1951),

Schuck

(1945), w o r k i n g in N e w York,

w o r k i n g in N e w Zealand,

hav e r e c o r d e d s p a t i a l

stabili ty in p o p u l a t i o n s of b r o w n trout,
of c u t t h r o a t trout,

while populations

Sa lmo c l a r k i , ha ve al so b e e n shown to

display l im i t e d m o v e m e n t s

(Miller,

in a l o n g - t e r m study of b r o o k
three M i c h i g a n s t r e a m s , has
p o pul a t i o n as a w h o l e
eral years,

and

1957).

She t t e r

(1968),

and b r o w n t r o u t m o v e m e n t

in

shown t h a t m o v e m e n t of the

is l i m i t e d e v e n o v e r p e r i o d s of s e v ­

although individual

fish m a y mov e c o n s i d e r a b l e

distances.
No t all s t r e a m stu d i e s of fish m o v e m e n t ha ve b e e n
limited to c o l d - w a t e r s p e c i e s .

S ev e r a l

authors hav e shown

that s m a l l m o u t h ba ss d i s p l a y l i m i t e d mov eme nt,
periods of up to two y ear s
Funk,

1955;

Brown,

1961;

(Tate,

1950;

a n d Fajen,
52

e v e n after

Lar imore,

1962).

Linton

1952;

53
(unpublished M.S.
brary,

1964)

thesis,

and G e r k i n g

M i c h i g a n State U n i v e r s i t y L i ­
(1953)

found sp a t i a l s t a b i l i t y in

st rea m p o p u l a t i o n s of rock bass,

and the same p h e n o m e n o n

has b een r e c o r d e d in s t r e a m p o p u l a t i o n s of s h a r p f i n c h u b —
suckers,

E r i m y z o n tenuis

bl uegills
and Shoop,

(Gunning and S h o o p , 1964),

and l o n g e a r sunfish,

Lepomis megalotis

and

(Gunning

1963).

It has be en p r o p o s e d th at this sp a t i a l s t a b i l i t y
in st r e a m fish p o p u l a t i o n s m ay be a result of t e r r i t o r i a l ­
ity or hierarchy,

and that an in cr e a s e in d e n s i t y above

some t h r e s h o l d level m a y g e n e r a t e a p o p u l a t i o n of t r a n s i e n t
fish.

This w o u l d the n te nd to inc re a s e the d e g r e e of

mo vement sh own by the p o p u l a t i o n as a w h o l e
1953;

Jenkins,

1969).

How ever,

(Gerking,

it app e a r s t hat a d e c r e a s e

in d en s i t y of b r o w n t r o u t ov er 6-i nches

in tot al

length

from an e s t i m a t e d 256 p e r m i l e of s t r e a m in 1968 to an
estimated 106 per m ile in 1969 in the Pine Ri ver r e s u l t e d
in no change in the d e g r e e of m o v e m e n t of this population.
It may be arg ued that the p o p u l a t i o n in the study
area was not,

in fact,

r e d u c e d in 1969,

of y o u n g - o f - y e a r m a y h a v e m o r e
of the o lde r fish.

b ut t hat the n umb er

than m a d e up for the losses

T hus a cha nge

in the de g r e e of m o v e m e n t

of the p o p u l a t i o n w o u l d not be expected.

A l t h o u g h no e s ­

timates of the p o p u l a t i o n of s m a l l e r trout w e r e made,

the

number caught w i t h the e l e c t r i c sho c k e r d u r i n g 1969 was
many times the n u m b e r c a u g h t in 19 68.

However,

e ven if

54
the losses

amo ng the o l d e r fish w e r e c o m p e n s a t e d b y the

a ddi t i o n of these y o u n g - o f - y e a r ,
patterns of the o l d e r
have be en obs er v e d ,

a c h a n g e in the m o v e m e n t

f i s h — if it o c c u r r e d — s h o u l d still

sin ce

alent to la r g e r fish.

fry are not b e h a v i o r a l l y e q u i v ­

Braddock

have sho wn t hat size c onf e r s
among fish k e p t in aquaria,

(1945)

an d G r e e n b u r g

(1947)

an a d v a n t a g e in h i e r a r c h i e s
w h i l e Je n k i n s

(1969)

has o b ­

served the same e f f e c t for t e r r i t o r i a l b r o w n t r o u t in
streams.

He also o b s e r v e d that p r i o r r e s i d e n c e c o n f e r r e d

advantage a mon g th ese fish.

Chapman

(1962)

has

same size a d v a n t a g e a m o n g ju ve n i l e coh o salmon,
kisutch.

This size ad van tag e,

Oncorhynchus

c o u p l e d w i t h the p r i o r r e s ­

idence ef f e c t and the d i f f e r e n c e s
between fry and a d u l t s a l m o n i d s

shown the

in h a b i t a t u t i l i z a t i o n

(McCrimmon,

1954)

makes

it

unlikely that fry c o u l d alt er the m o v e m e n t s of larger trout.
If s ocial c o n t r o l is a s t r o n g r e g u l a t o r y m e c h a n i s m
in salmonids as has b e e n s u g g e s t e d b y C h a p m a n

(1966),

as de n s i t y i n c r e a s e d p a s t some t h r e s h o l d level,

then

presumably

more fish w o u l d be f o r c e d to a s s u m e a t r a n s i e n t role.
LeCren

(1965)

n ote s tha t in t e r r i t o r i a l

fis hes d i s p e r s i o n

may ope r a t e in a m a n n e r q u i t e s i m i l a r to m o r t a l i t y .

This

m e c h a n i s m m i g h t then serve to m a i n t a i n o p t i m u m s t o c k i n g
levels.

These ideas

see m c o n s i s t e n t w i t h the s t a t e m e n t s

of Ge r k i n g and Jenkins.
In v i e w of the p r e s e n t d a t a it w o u l d a p p e a r that
the n ece s s a r y t h r e s h o l d level r e q u i r e d for an i n c r e a s e d

55
de gre e of m o v e m e n t w as no t attained.
the case,

If this wa s

t hen we n e e d n ot r e j e c t the h y p o t h e s i s ,

wo rk tha t has b e e n c omp lete d,
Kalleberg
d e n s i t y of

(1958)

has

r e j e c t i o n se ems

in fact
an d from

impossible,

shown t hat in s t r e a m aqu aria,

j uv e n i l e A t l a n t i c

salmon,

as the

S a l m o s a l a r , increa sed ,

the p o p u l a t i o n b e c a m e d i v i d e d into two g r o u p s :

those which

held t e r r i t o r i e s an d t h o s e w h i c h w e r e r e p e a t e d l y chased.
The latter g r o u p w o u l d p r e s u m a b l y b e c o m e t r a n s i e n t s
vo lit ion al p o p u l a t i o n .

in a

T he d e n s i t y n e c e s s a r y to cau se the

d e v e l o p m e n t of a t r a n s i e n t p o p u l a t i o n was

considerably

higher t han w o u l d be e x p e c t e d in m o s t n a t u r a l p o p u l a t i o n s
if the e n t i r e are a o f s t r e a m is c o n s i d e r e d ,
than 200-250
ever,

being greater

fry p er 10 s q u a r e f eet of b o t t o m area.

How­

not all areas of a s t r e a m can be c o n s i d e r e d as s u i t ­

able h a b i t a t for y o u n g s a l m o n i d s and it is p o s s i b l e that
densities of this m a g n i t u d e m a y b e r e a c h e d in n a t u r a l p o p ­
ulations w h e n u n s u i t a b l e h a b i t a t s

are e x c l u d e d f r o m

consideration.
I n d i r e c t e v i d e n c e that a t r a n s i e n t
does d e v e l o p u n d e r n a t u r a l
Elliott

(1966)

fry p o p u l a t i o n

stream conditions

is available.

r e p o r t e d the o c c u r r e n c e of b r o w n t r o u t fry

in dri ft samples,

and c u t t h r o a t t r o u t fry hav e b e e n r e ­

ported as m o v i n g d o w n s t r e a m in a r t i f i c i a l s t r e a m c h a n n e l s
(Smith,

1944).

Chapman

(1962)

als o c o n c l u d e d t hat a g g r e s ­

sive beh a v i o r a p p e a r e d to be a m a j o r

fa cto r in c a u s i n g

d o w n s t r e a m m o v e m e n t s of juv en i l e c o h o salmon.

56
A d e n s i t y r e g u l a t i n g m e c h a n i s m o f this type has
not b e e n d e m o n s t r a t e d
but if it occurs,

for a d u l t s a l m o n i d s

to m y k n o w l e d g e ,

the t h r e s h o l d level n e c e s s a r y to g e n e r a t e

a t r a n s i e n t p o p u l a t i o n is l i k e l y n e v e r a t t a i n e d in an
adult b r o w n t r o u t p o p u l a t i o n

in nature*

If this

is true,

our h y p o t h e s i s m u s t be r e v i s e d to i n c l u d e on ly the y o u n g e r
segment of the pop u l a t i o n .

S o c i a l r e g u l a t i o n of n u m b e r s

wo uld then be e x p e c t e d to o c c u r o n l y a m o n g the y o u n g

fish.

C o m p e t i t i o n for t e r r i t o r i e s a m o n g the fry w o u l d r e s u l t in
mo ve m e n t of the ex ces s

fish to less

favorable habitats

where th ey w o u l d be s u b j e c t to a d d i t i o n a l h azards.
growth o c c u r r e d and n e w h a b i t a t s w e r e required,

As

the fry

wo uld be t h r o w n into c o m p e t i t i o n w i t h o l d e r fish.

Since

size and p r i o r r e s i d e n c e c o n f e r s t r o n g a d v a n t a g e s on the
older fish in c o n t e s t s

for te rri t o r y ,

cruitment of the y o u n g e r

the e x t e n t of r e ­

fish into the adult p o p u l a t i o n

would ap pea r to o f f e r a f urt h e r o p p o r t u n i t y
regulation to occur.

for so c i a l

T h e e x c e s s p o r t i o n of y o u n g fish

would then be fo rce d to a s s u m e the role of transients.
After these in i t i a l a d j u s t m e n t s h a v e taken place,

the

regulation of d e n s i t y in the p o p u l a t i o n m a y d e p e n d u p o n
the g radual d i s p e r s a l of the o l d e r trout as w a s d e m o n ­
strated in the p r e s e n t study.
compensate

This w o u l d be n e c e s s a r y to

for the i n c r e a s e d b i o m a s s r e s u l t i n g
has i n d i c a t e d

this p h e n o m e n o n

f rom growth.

Jenkins

(1969)

in b r o w n

trout.

In e n c l o s e d s ect i o n s of a r t i f i c i a l str eams,

he

57
o b s e r v e d w h a t he t e r m e d
this b eha v i o r ,

"r oaming"

in i n d i v i d u a l

which occurred spontaneously

apparen t reason,

these fish w o u l d h a v e
given the o p p o r t u n i t y .

and for no

for p e r i o d s of

It is p r o b a b l e t h a t

left the e n c l o s u r e
In o b s e r v a t i o n s

he o b s e r v e d that t e r r i t o r i a l

if t hey h a d b e e n
in the Ow ens

f r o m 5 to 70 days,

r emained in the are a t h r o u g h o u t
T hes e p e r i o d i c

but eventually

(Chapman,

No

fish

the e n t i r e p e r i o d of o b ­

s hifts of t e r r i t o r y m a y be

ex plained by the c h a n g i n g r e q u i r e m e n t s
grow larger

River,

fish m a i n t a i n e d t h e i r t e r r i ­

left the o b s e r v a t i o n ar ea a nd d i d not return.

servation.

In

a f ish w o u l d be s e e n to l eav e his r e f u g e

and r o a m o v e r the e n t i r e channel.

tories

fish.

1966).

of fish as they

Further credence

for this

e x p l a n a t i o n of ad ult t r o u t m o v e m e n t is le nt by the r e m a r k
by M i l l e r

(1957)

th at r e p o p u l a t i o n of p o i s o n e d s e c t i o n s of

streams by adu lt c u t t h r o a t t r o u t wa s q u i t e slow.

It has

also b een found that t r a n s i e n t coh o s a l m o n fry w e r e
than the r e s i d e n t s
notably C h a p m a n

(Chapman,

(1962)

1962),

and K a l l e b e r g

and n u m e r o u s
(1958)

smaller

authors,

h a v e sho wn

that d e s p o t i c fish in h i e r a r c h i e s o r s u c c e s s f u l

territorial

fish g row m ore r a p i d l y th an s u b o r d i n a t e s or r e f u g e e s „
primary d i r e c t i o n of m o v e m e n t of t h e s e t r a n s i e n t

The

fry is

d o w n s t r e a m a n d thus if a t r a n s i e n t a d u l t p o p u l a t i o n w e r e
present it w o u l d be e x p e c t e d tha t a t r e n d t o w a r d d o w n s t r e a m
m o vem ent w o u l d be det ecte d.
present study,

nor has

This wa s n o t the case in the

it b e e n the ca se

in any o t h e r s t u d y

of trout m o v e m e n t tha t I h a v e e n c o u n t e r e d .

58
It is i m p o r t a n t he re to r e c o g n i z e that this t e r r i ­
torial shift ing ,

w h i c h is p r o p o s e d to a c c o u n t

for the

m o v e m e n t s of the a dul t m e m b e r s of the p o p u l a t i o n ,

m a y be

an i n d i v i d u a l r e s p o n s e to p h y s i c a l e n v i r o n m e n t or food
requirements,

a nd not a r e s u l t of c o n t e s t for territory.

In this context,

d e n s i t y w o u l d pla y no role

in e f f e c t i n g

this m o v e m e n t .
If this

line of r e a s o n i n g is contin ued ,

it follows

that the p i o n e e r i n g role of b r o w n trou t p o p u l a t i o n s w o u l d
fall p r i m a r i l y to the excess y o u n g w h i c h ha ve b e e n
to assume a t r a n s i e n t role,
of losses to the ma ture,

forced

t h e r e b y m i n i m i z i n g the d a n g e r

r e p r o d u c i n g s e g m e n t of the p o p u ­

lation .
In J e n k i n ’s 196 9 p a p e r he m e n t i o n s th at he

found a

transie nt g r o u p of fish a mon g the a d u l t p o p u l a t i o n in the
Owens River.
have come

He was

at a loss to e x p l a i n w h e r e th ey m i g h t

from or w h y they sh o u l d exist.

It is p o s s i b l e

that these fish are the s u r v i v o r s of the g r o u p d i s p l a c e d
at a yo u n g e r age,

but this

is unlikely.

Larkin

(1956)

has

su ggested that th ese t r a n s i e n t s w o u l d be m o s t s u s c e p t i b l e
to p r e d a t i o n b e c a u s e of their s l o w e r g r o w t h rates.
ing a b e n i g n e nvi r o n m e n t ,
may occur,

Assum­

some s u r v i v a l of t r a n s i e n t

fry

h o w e v e r such a b e n i g n e n v i r o n m e n t is d i f f i c u l t

to con ceive of for a fish s pecies w h i c h has b e e n r e p o r t e d
to su stain annual

losses of at l east 40%.

Jenkins indi­

cated that a few of the t r a n s i e n t s w e r e s u c c e s s f u l in

59
displacing territorial

fish,

and thus

u. .ere m a y h ave b e e n

some sort of e q u i l i b r i u m r e a c h e d b e t w e e n the t r a n s i e n t s
and t e r r i t o r i a l s e g m e n t s of the p o p u l a t i o n w h e r e b y m e m b e r s
of each g r o u p s h i f t e d t h e i r roles
The sm a l l e r n u m b e r of t r a n s i e n t
in d i s p l a c i n g t e r r i t o r i a l
this po s s i b i l i t y .
which a ppears

roaming fish,

fish w h i c h w e r e s u c c e s s f u l

fish w o u l d s e e m to o b l i t e r a t e

A fur t h e r p o s s i b i l i t y exi sts,

however,

to be the m o s t l i k e l y e x p l a n a t i o n to a c c o u n t

for these t r a n s i e n t adults.
'transients'

for a p e r i o d of time.

This p o s s i b i l i t y is t h a t the

o b s e r v e d by J e n k i n s m a y not h a v e b e e n

free-

but actually may have been territorial

which w e r e in the p r o c e s s of s h i f t i n g te rr i t o r i e s .
stated that the se

'transients'

of the total pop u l a t i o n ,
range of p e r c e n t a g e s

(27-33)

m a d e up b e t w e e n 20 and 30%

for r e c a p t u r e s

showing m o v e ­

T h e s e r e c a p t u r e s w ere o r i e n t e d

arcund the s ect i o n s of o r i g i n a l captu re,
f r e e - r o a m i n g fish.

been the case w i t h the

J enk ins

w h i c h a gr e e s q u i t e w e l l w i t h the

ment in the p r e s e n t study.

be c o n s i d e r e d as

fish

'transients'

and thus c a n n o t

This m a y h ave also
mentioned

in J e n k i n ' s

paper.
It is c o n c l u d e d t h a t if so cia l r e g u l a t i o n of d e n ­
sity occurs a mon g s t r e a m - d w e l l i n g b r o w n t rou t p o p u la tio ns,
it mu st be o p e r a t i v e on ly am o n g the y o u n g e r
its peak soon after the fry e m e r g e

fish,

reaching

from the gravel,

gradual ly d e c l i n i n g in i m p o r t a n c e as the fish b e c o m e

and
larger.

This m e c h a n i s m w o u l d th en serve to pass the p i o n e e r i n g

60
role do wn to the y o u n g e r fish an d r e d u c e the h a z a r d s
the older,

r e p r o d u c i n g s e g m e n t of the po p u l a t i o n .

social r e g u l a t i o n d u r i n g the fry st age w o u l d al so

to

Strong
function

to re duce the d e g r e e of c o m p e t i t i o n a m o n g the o l d e r

fish,

and thus i n c r e a s e the e f f i c i e n c y of e n e r g y u t i l i z a t i o n .
The annual p r o d u c t i o n of fry w o u l d th en s erv e t wo u s e f u l
purposes:

r e c r u i t m e n t i nto the po p u l a t i o n ,

with o p t i m u m u s a g e of the a v a i l a b l e habitat?
ing of areas of p o t e n t i a l l y n e w habitat.
but d a n g e r o u s tas k of p i o n e e r i n g w o u l d
a m i n i m u m e x p e n d i t u r e of energy.
pr oposed to in s u r e t hat th ese d u a l

consistent
and p i o n e e r ­

The n e c e s s a r y

thus r e q u i r e only

So c i a l r e g u l a t i o n m a y be
fun cti ons

are f u l f i l l e d

with a m i n i m u m loss of e n e r g y to the p o p u l at ion .

SUMMARY
Although

i n f o r m a t i o n on ch a n g e s

in the s t u d y a r e a is limited,

fish p o p u l a t i o n

sa m p l e s t a k e n d u r i n g

and 196 9 i n d i c a t e d an i n c r e a s e
ri ver chubs

in the

1968

in the a b u n d a n c e of

and b r o o k t r o u t in 1969 a nd a d e c l i n e

in

ab u n d a n c e of l a r g e r w h i t e suckers.
Br own trout ove r
ab und a n c e

6- inc h e s

in to tal

fro m an e s t i m a t e d

256 per m i l e of s t r e a m in

196 8 to an e s t i m a t e d 106 per mil e
for this d e c l i n e w a s
me nt

f rom the

in 1969.

The r e a s o n

a p p a r e n t l y due to a low r e c r u i t ­

196 8 y e a r class.

The 106 r e c a p t u r e s
s t r e a m sec tion

l e n g t h d e c l i n e d in

r e c o r d e d in 1968

f r o m one 1 4 0 0 - f o o t

i n d i c a t e d a p r o n o u n c e d t e n d e n c y for

trout o ver 6-inches

in total

l e n g t h to lim it their

m o v e m e n t s d u r i n g the summer.
M o v e m e n t of tr out ove r 6 - inches
su mme r of 196 9 was

in l e n g t h d u r i n g the

a g a i n limited,

as s h o w n by the

locations of the 97 r e c a p t u r e s of t r o u t m a r k e d

in

1969.
The locatio ns of the fi rst 196 9 r e c a p t u r e s o f 24 trout
m a r k e d in 1968 i n d i c a t e d t hat the fish e i t h e r m o v e d
very little ove r the w i n t e r or r e t u r n e d to areas o c ­
c u p i e d the p r e v i o u s summer.

F u r t h e r r e c a p t u r e s of

62
t hes e

24 t r o u t d u r i n g the s u m m e r i n d i c a t e d that t h e i r

movements had again become
6.

limited.

T he p a t t e r n s of m o v e m e n t of trout w i t h i n the three
s e c t i o n s s a m p l e d in 1969 did not d i f f e r
or

f r o m ea ch o the r

fr om the m o v e m e n t p a t t e r n r e c o r d e d for t r o u t r e c a p ­

t u red w i t h i n one s e c t i o n s a m p l e d in 1968.
7.

A p p a r e n t l y the d e c r e a s e in the d e n s i t y of t r o u t o v e r
6 - in c h e s in l e n g t h w h i c h o c c u r r e d in the study

area

fr om 1968 to 1969 di d n ot al ter the m o v e m e n t p a t t e r n
of the p o p u l a t i o n of tr out ove r

6- in c h e s

in l ength as

was expected.
8.

It is s u g g e s t e d that a p o s i t i v e r e l a t i o n s h i p b e t w e e n
d e n s i t y and the d e g r e e of m o v e m e n t s h o w n by b r o w n
tr out p o p u l a t i o n s exists,

a nd t hat this

relationship

acts as a d e n s i t y r e g u l a t i n g m e c h a n i s m by i n c r e a s i n g
e m i g r a t i o n at h i g h e r de nsi tie s.

The m e c h a n i s m probably

acts p r i m a r i l y a m o n g the fry and b e c o m e s
d i m i n i s h e d in e f f e c t by the time the
inches in length.

considerably

fish r e a c h 6-

This m e c h a n i s m w o u l d t hen act to

co ns e r v e e n e r g y and i n s u r e a d e q u a t e r e p r o d u c t i o n
w i t h i n the p o p u l a t i o n .

LITERATURE CITED

LITERATURE CITED
Allen,

K. R.
1951.
The H o r i k i w i stream.
A s t u d y of a
trout p o p u l a t i o n .
N e w Z e a l a n d M a r i n e D e p t . , Fish
B u l l . N o . 10, 2 31 p p .

Beyerle,

G. B. and E. L. Cooper.
1960.
G r o w t h of b r o w n
trout in s e l e c t e d P e n n s y l v a n i a streams.
Trans.
Am. Fish. Soc. 89 (3) :255-262.

B o u c k , G. R. and R. C. Ball.
1966.
I n f l u e n c e of c a p t u r e
m e t h o d s on b l o o d c h a r a c t e r i s t i c s and m o r t a l i t y in
the r a i n b o w t r o u t (Sa lmo g a i r d n e r i ).
Trans. Am.
Fish. Soc. 95 (2}:170-176.
Braddock, J. C.
1945.
Som e a spects of the d o m i n a n c e s u b o r d i n a t i o n r e l a t i o n s h i p in the fish P l a t y p o e cilus m a c u l a t u s . Physiol. Z o o l . 1 8 ( 2 ) :176-195„
Brown,

E. H. Jr.
1961.
M o v e m e n t of n a t i v e and h a t c h e r y r e a r e d gam e fish in a w a r m - w a t e r stream.
Trans.
Am. Fish. Soc. 9 0 ( 4 ) ; 449- 456 .

Brynildson, O. M. and C. L. B ry n i l d s o n .
1967.
The e f f e c t
of p e c t o r a l and v e n t r a l fin re mov al on s u r v i v a l
and g r o w t h of w i l d b r o w n t r o u t in a W i s c o n s i n
stream.
Trans. Am. Fish. Soc. 96 (3) :353-355.
Brynildson, O. M . , V. A. H a c k e r and T. A. Klick.
1963.
B r o w n t r o u t — its life h istory, ecology, and m a n ­
agement.
P u b l i c a t i o n 234, W i s c o n s i n C o n s e r v a t i o n
De par tme nt, M a d i s o n 1, Wi sco nsin .
15 pp.
Burnet, A. M. R.
1959.
Som e o b s e r v a t i o n s on n a t u r a l
fl u c t u a t i o n s of t r o u t p o p u l a t i o n numbers.
New
Ze aland J. of Sci. 2 (3):410-421.
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1969.
H a n d b o o k of f r e s h w a t e r fis her y
biology.
Vol. I.
Iowa S t a t e U n i v e r s i t y Press,
Ames, Iowa.
75 2 pp.
Chapman,

D. W.
1962.
A g g r e s s i v e b e h a v i o r in juv eni le
coho s a l m o n as a cau se of e mig rat ion .
J. Fish.
Res. Brd. C a n a d a 19 (6):1047-1080.

63

64
Chapman,

D. W.
1966.
F o o d and space as r e g u l a t o r s of
s a l m o n i d p o p u l a t i o n s in streams.
The Amer. Natur.
1 0 0 { 9 1 3 ) : 3 4 5 — 357.

Cochran,

W. G.
1952.
The C h i - s q u a r e test of g o o d n e s s of
fit.
Ann. Math. Stat, 23:315-345.

Cooper,

G. P. and K. F. Lagler.
1956.
A p p r a i s a l of
m e t h o d s of fish p o p u l a t i o n s t u d y — Pa rt III.
The
m e a s u r e m e n t of fish p o p u l a t i o n size.
Trans. 21st
N o r t h Amer. Wildl. C o n f ., pp. 281-297.

Elliott,

J. M.
1966.
D o w n s t r e a m m o v e m e n t s of t r o u t fry
(Salmo trutta) in a D a r t m o o r stream-,
J. Fish. Res
Brd . C a n a d a 23 (1) :157-159 „

Embody,

D. R.
1940.
A m e t h o d of e s t i m a t i n g the n u m b e r of
fish in a stream.
Trans. Am. Fish. Soc. 69: 231 236 .

Fajen,

O. F.
1962.
T he i n f l u e n c e of s t r e a m s t a b i l i t y on
h o m i n g b e h a v i o r of two s m a l l m o u t h bass populations,
Trans. Am. Fish. Soc. 9 1:346-349.

Funk, J. L.
1955.
Trans. Am.

M o v e m e n t of s t r e a m fishes
Fish. Soc. 85:39-57.

in Missouri.

Gerking,

S. D.
19 53.
E v i d e n c e for th e c o n c e p t s of ho me
ra nge a n d t e r r i t o r y in st r e a m fishes.
Ecol. 34:
347-365.

________ .

1959.
tions.

Graham,

T. R. a n d J. W. Jones.
1962.
The b i o l o g y of Llyn
T e g i d trout, 1960.
Proc. Zool. Soc. L o n d o n 139(4):
657-683.
(In_:
C arl an d e r , K. D.
1969.
Handbook
of f r e s h w a t e r fis h e r y biology.
Vol. I. Iowa
State U n i v e r s i t y Press, Ames, Iowa.
752 pp.)

Th e r e s t r i c t e d m o v e m e n t of fish p o p u l a ­
Biol. Rev. 34 (2):221-242„

Greenburg, B.
1947.
Some r e l a t i o n s b e t w e e n territory,
s ocial h i e r a r c h y , an d l e a d e r s h i p in the gr een
su n f i s h (Lepomis c y a n e l l u s ) . Physiol. Zool.
20 (3) :267-299.
Grudniewski, C.
1961.
(An a t t e m p t to d e t e r m i n e the c r i t ­
ical t e m p e r a t u r e a nd o x y g e n c ont e n t s for fry of
W d z y d z e L ake t r o u t (S a l m o t r u t t a m o r p h a l a c u str is
L . ).) (Eng. summary.!
R o c z . N a u k R o l n r c z y c h 93:
627-648.
(Iii:
Ca r l a n d e r , K. D.
1969.
Handbook
of f r e s h w a t e r f i s h e r y biology.
Vol. I. Iowa
State U n i v e r s i t y Press, Ames, Iowa.
752 pp.)

65
Gunning,

G. E. and C. R. Shoop.
1963.
O c c u p a n c y of h o m e
ra nge by l on g e a r sunfish, Le p o m i s m. m e g a l o t i s
( R a f i n e s q u e ) , an d bl uegill, Le p o m i s m. m a c r o c h i r u s
Rafinesque.
Anim, Behav. 11:325-330.

________ and
.1964. S t a b i l i t y in a h e a d w a t e r
s t r e a m p o p u l a t i o n of the s h a r p f i n chubsucker,
Prog. Fish-Cult. 26(2):76-79.
Horak,

D. L. and W. D. Klein.
1967.
I n f l u e n c e of c a p t u r e
m e t h o d s on fis h i n g success, stamina, and m o r t a l i t y
of r a i n b o w t r o u t (S a l m o g a i r d n e r i ) in Colorado.
Trans. Am. Fish. Soc. 96 (2) :220-222.

Jenkins,

T. M. Jr.
1969.
So c i a l structure, p o s i t i o n
ch oic e and m i c r o d i s t r i b u t i o n of two t r o u t sp e c i e s
(S a l m o t r u t t a and S alm o g a i r d n e r i ) r e s i d e n t in
m o u n t a i n streams.
Anim. Behav. Mono. 2(2):57-123.

Kalleberg, H.
1958.
O b s e r v a t i o n s in a s t r e a m t ank of
t e r r i t o r i a l i t y and c o m p e t i t i o n in ju ve n i l e sa l m o n
and t rou t (Salmo s ala r L. and S. t r u t t a L . ).
Inst. F r e s h w a t e r Res., R e p t . , No. 39, pp. 55-98.
Lane,

E. D.
1964.
B r o w n tr out (Sal mo t r u t t a ) in the
Hinds River.
Proc. N e w Ze aland Ecol. Soc. 11:10-16.

L a r i m o r e , R. W.
1952.
Ho me pools and h o m i n g b e h a v i o r of
s m a l l m o u t h b l a c k ba ss in J o r d a n Creek.
111. Nat.
Hist. Survey, Biol. N o t e s No. 28.
12 pp.
Larkin,

P. A.
1956.
I n t e r s p e c i f i c c o m p e t i t i o n and p o p u ­
la tio n con t r o l in f r e s h w a t e r fish.
J, Fish. Res.
Bd. C a n a d a 13 (3) :327-342.

LeCren,

E. D.
1965.
Some factors r e g u l a t i n g the si ze of
p o p u l a t i o n s of f r e s h w a t e r fish.
Mitt. Internat.
Verein. Limnol. 13:88-105.
(I n : C hap m a n , D„ W.
1966.
Food and spa ce as r e g u l a t o r s of s a l m o m d
p o p u l a t i o n s in streams.
Th e Amer. Natur. 100(913):
345-357.)

Linton,

K. J.
1964.
Dy nam i c s of the fish p o p u l a t i o n s in
a w a r m - w a t e r stream.
(unpublished M.S. thesis,
M i c h i g a n S tat e Univ. Library, E a s t La nsing, Mich.)

McCrimmon, H. R.
1954.
S t r e a m s tudies on p l a n t e d A t l a n t i c
salmon.
J. Fish. Res. Bd. C a n a d a 1 1 ( 4 ): 362 -40 3„
McFadden, J. T. and E. L. Cooper.
1962.
An e c o l o g i c a l
c o m p a r i s o n of six p o p u l a t i o n s of b r o w n tr out (Salmo
trutta).
Trans. Am. Fish. Soc. 91(l):53-62.

66
Miller,

R. B.
1957.
P e r m a n e n c e and size of ho me t e r r i t o r y
in s t r e a m - d w e l l i n g c u t t h r o a t trouts
J. Fish. Res.
Bd. C a n a d a 14 (5) :687-691.

Nelson,

W. C.
1960.
A c o m p a r i s o n of the losses o f jaw,
cheek, dart,
and s p a g h e t t i tags; and th eir e f f e c t s
on the s u r v i v a l and gr o w t h of t r o u t u n d e r h a t c h e r y
co nditions.
C o l o r a d o Dept, of Ga me and Fish,
Denver, Colorado.
20 pp.

Radcliffe, R. W.
1950.
The e f f e c t of f i n - c l i p p i n g on the
c r u i s i n g s p e e d of g o l d f i s h and co ho s a l m o n fry.
J. Fish. Res. Bd. C a n a d a 8(2):67-73.
Schuck,

H. A.
1945. Sur vival, p o p u l a t i o n density, and
m o v e m e n t of the w i l d b r o w n t r o u t in C r y s t a l Creek.
Trans. Am. Fish. Soc, 73:209-230.

Shetter,

D. S.
1936.
M i g r a t i o n , g r o w t h rate, and p o p u l a ­
tion d e n s i t y of b r o o k trout in the n o r t h b r a n c h of
the A u S a b l e River, Mi chigan.
Trans. Am, Fish. Soc.
66 :203-210.
1952.
Th e m o r t a l i t y and g r o w t h of m a r k e d
and u n m a r k e d lake t r o u t f i n g e r l i n g s in the p r e s e n c e
of pre dat ors .
Trans. Am. Fish. Soc, 81:17-34.
______ . 1967.
E f f e c t s of jaw tags and fin e x c i s i o n
up on the growth, survival, a n d e x p l o i t a t i o n of
h a t c h e r y r a i n b o w t r o u t f i n g e r l i n g s in Mic hig an,
Trans. Am. Fish. Soc. 96 (4):394-399,
1968.
O b s e r v a t i o n s on m o v e m e n t s of w i l d
trout in two M i c h i g a n s t r e a m dra ina ges .
Trans,
Am. Fish. Soc. 97 (4) : 472-480.

Smith, O. R.
194 4.
R e t u r n s f rom n a t u r a l s p a w n i n g of c u t ­
th r o a t t r o u t and e a s t e r n b r o o k trout.
Trans. Am.
Fish. Soc. 74:281-295.
Stauffer, T. M. and M. J. Hansen.
1969.
M a r k retenti on,
survival, and g r o w t h of j a w - t a g g e d and f i n - c l i p p e d
r a i n b o w trout.
Trans. Am. Fish. Soc. 98(2) :225229.
Strawn,

K.
1958.
O p t i m u m and e x t r e m e t e m p e r a t u r e s for
growth and survival:
v a r i o u s fishes.
Fo r h a n d b o o k
of b i o l o g i c a l data.
1 p. table.
(l£.: Car lan der ,
K. D.
1969.
H a n d b o o k of f r e s h w a t e r f i s h e r y b i o ­
logy.
Vol. I.
Iowa Sta te U n i v e r s i t y Press, Ames,
I o w a . 752 p p .)

67
Tate,

W,

Thomas,

H.
1950.
S t u d i e s on s m a l l m o u t h b l a c k ba ss in
Io wa streams:
s t r e a m d y n a m i c s and s m a l l m o u t h
m o v e me nt.
Iowa State C oll e g e , P r o j e c t 38.
3 pp.
( M i m e o .)
J. D.
196 4.
S tu d i e s on the g r o w t h of trout,
Sa lmo t r u t t a , fr om four c o n t r a s t i n g habitats.
Proc. Z o o l . Soc. L o n d o n 142 (3):459-509.
(In:
C a r l a n d e r , K. D.
1969.
H a n d b o o k of f r e s h w a t e r
f i s h e r y biology.
Vol. I.
Iowa S tat e U n i v e r s i t y
Press, Ames, Iowa.
752 pp.)

APPENDIX

68

Nu mbers of b r o w n t r o u t m a r k e d and the n u m b e r s r e c a p t u r e d
in the s e v e n s tat i o n s c o m p r i s i n g s e c t i o n B on each s a m p ­
ling d a t e d u r i n g 1968.
(numbers in p a r e n t h e s e s r e p r e s e n t
recaptures)
Station
4

Date
1

2
5

July 6

14

3

6

5

7

2

1

6

1

9

July 16

1
(3)

6
(3)

0
(1)

1
(0)

0
(2)

0
(0)

1
(1)

July 19

1
(2)

2
(3)

1
(1)

1
(0)

0
(5)

0
(0)

1
(1)

July 23

0
(0)

0
(6)

0
(1)

1
(0)

0
(0)

0
(0)

2
(1)

Aug.

0
(0)

1
(2)

0
(1)

0
(0)

2
(1)

0
(0)

0
(0)

A u g . 19

0
(2)

1
(7)

0
(2)

0
(0)

0
(0)

0
(0)

0
(1)

A u g . 27

1
(2)

1
(7)

0
(1)

1
(0)

0
(2)

0
(0)

0
(2)

Sept.

11

0
(1)

0
(7)

0
(1)

0
(2)

1
(3)

0
(0)

0
(1)

Sept.

17

0
(2)

0
(6)

0
(2)

0
(1)

0
(2)

0
(0)

0
(3)

Sept.

25

0
(2)

0
(7)

0
(1)

0
(1)

0
(1)

0
(0)

0
(2)

8
(14)

25
(48)

3
(11)

5
(4)

9
(16)

1
(0)

13
(12)

6

Total
Grand total

64

(105)

69

Nu mbers of b r o w n t r o u t m a r k e d in e a c h s t a t i o n a n d the
numbers of r e c a p t u r e s of fish m a r k e d in e ach s t a t i o n in
the s eve n s t a t i o n s c o m p r i s i n g s e c t i o n A on ea ch s a m p l i n g
date d u r i n g 1969.
(numbers in p a r e n t h e s e s r e p r e s e n t r e ­
captures of fish m a r k e d in s e c t i o n A in 1969, u n d e r l i n e d
numbers r e p r e s e n t m a r k e d fish r e c a p t u r e d in o t h e r
sections)
Date

Station
4

5

6

1

3

2

3

0
(0)

2
(1)

1
(1)

2
(2)

0
(3)

1
(0)

1
(0)

0
(3)

0
(1)

0
(0)

2
(1)

0
(0)

0
(0)

0
(0)

0
(0)

0
(0)

0
(0)

1
(0)

0
1(0)

0
(0)

0
(0)

1
(0)

0
(1)

1
(0)

0
(1)

July 14

0
(0)

0
(0)

0
(0)

0
(0)

0
(1)

0
(0)

0
(0)

July 22

0
(I)

0
(1)

0
(0)

0
(0)

1
(1)

0
(1)

0
(1)

July 2 8

0
(0)

0
(0)

0
(0)

0
(0)

0
(0)

0
(1)

2
(1)

Aug.

0
(1)

0
(0)

0
(0)

0
(0)

0
(0)

0
(1)

0
(2)

0
(0)

0
(0)

0
(0)

1
(0)

0
(0)

0
(0)

0
(2)

7
2(6)

5
(3)

1
(0)

5
(4)

5
(5)

5
(5)

8
(11)

2

3

4

0

2
1<2>

0
(2)

June 16

1
(2)

June 2 3

1
June 2
June 9

July 9

5

A u g . 21

Total
Grand total

4

36

(34)

2

7

70

N umbers of b r o w n trout m a r k e d in eac h s t a t i o n and the
n u mbers of r e c a p t u r e s o f fish m a r k e d in e ach s ta t i o n in
the s e v e n s ta t i o n s c o m p r i s i n g s e c t i o n B o n e a c h s a m p l i n g
date d u r i n g 1969.
(numbers in p a r e n t h e s e s r e p r e s e n t reca ptures of fish m a r k e d in s e c t i o n B in 1969, u n d e r l i n e d
numbers r e p r e s e n t m a r k e d fish r e c a p t u r e d in o t h e r
sections)
Station
4

Date
1

3

2

June 2

1

3

3

June 9

0
(1)

1
(1)

3
(0)

June 16

0
1(0)

1
(0)

June 2 3

0
(0)

July 9

5

7

6

3

1

1

0
1(1)

3
(1)

1
(0)

1
1(2)

0
1(2)

0
(1)

0
(1)

1
1(1)

0
1(1)

0
(0)

0
(0)

0
(0)

0
(0)

0
(0)

0
1(0)

0
(0)

0
(3)

0
(1)

0
(0)

0
(2)

0
(0)

0
(1)

July 14

0
(0)

0
(1)

0
(0)

0
(1)

0
(1)

0
(0)

0
(0)

July 22

0
(0)

2
(2)

0
2^(0)

0
(1)

0
(1)

0
1(1)

0
(0)

July 28

0
1(0)

1
(3)

0
3(0)

0
(0)

0
(0)

0
(1)

0
(0)

0
(0)

0
1(2)

0
1(0)

0
(0)

0
(0)

A u g . 21

0
1(0)

0
(0)

0
2(0)

0
(0)

0
(1)

0
(1)

0
(0)

Total

1
3 (1)

8
1(12)

6
9(3)

3
1(4)

4
(7)

3
1 <5)

4
3 (4)

Aug. 5

Grand total

29

(36)

20

3

0
Id)

0
(0)

71

Nu mbe rs of b r o w n trout m a r k e d in each s t a t i o n and the
nu mbe rs of r e c a p t u r e s of fish m a r k e d in eac h sta t i o n in
the s e v e n s t a t i o n s c o m p r i s i n g s e c t i o n C on e a c h s a m p l i n g
date d u r i n g 1969.
{numbers in p a r e n t h e s e s r e p r e s e n t r e ­
c a ptures of fish m a r k e d in s e c t i o n C in 1969, u n d e r l i n e d
numbers r e p r e s e n t m a r k e d fish r e c a p t u r e d in o t h e r
sections)

Date
1

2

3

Station
4

5

6

7

June 2

1

2

1

2

3

0

0

June 9

1
(0)

0
(2)

0
(1)

1
(0)

3
(2)

0
(0)

0
(0)

June 16

0
1(0)

0
(1)

0
(0)

0
(1)

1
(3)

0
(0)

0
(0)

June 2 3

0
(1)

0
(1)

0
(1)

1
(0)

0
I*1 *

0
(0)

0
(0)

July 9

0
(0)

0
(0)

0
(0)

0
(0)

0
(2)

0
(0)

0
(0)

July 14

1
(0)

0
(0)

0
(0)

0
(1)

0
(2)

0
(0)

0
(0)

July 22

0
(0)

0
(0)

0
(1)

0
(1)

1
(1)

0
(0)

0
(0)

July 28

0
(0)

0
(0)

0
(0)

0
(0)

0
(2)

0
(0)

0
(0)

Aug.

5

0
(0)

0
(0)

0
(0)

0
(0)

0
(1)

0
(0)

0
(0)

Aug.

21

0
(0)

0
(0)

0
(0)

0
(0)

1
(1)

0
(0)

0
(0)

3
1(1)

2
(4)

1
(3)

4
(3)

9
1(15)

0
(0)

0
(0)

Total
Grand total

19

(26)

2