TAGGING STIJDIES TO DETERMINE
THE OFFSHORE-INSHOW EXCHANGE
OF GROUNDFISH OFF OREXON AND WASHINGTON
FINAL REPORT
June 1961-February 1966
GARY S. MILBURN
F i s h Commission of Oregon
A s t o r i a , Oregon
UNITED STATES ATOMIC ENERGY COMMISSION
CONTRACT NO. AT (45-1) 1731
FEBRUARY 1966
TAB1.E OF CONTENTS
Page No.
............................................................
METHODS AND MATmIALS...................................................
RESITLTS .................................................................
IWRODUCTIOM
1
I
6
......................................................... 7
Sablefish .......................................................... 2'7
SITMMARY ................................................................. 30
EITERATllRE CITED. ....................................................... 3 1
Dover Sole
LIST OF FIGURES
Page No.
Figure No.
1.
2.
Area of investigation off northern Oregon and southern
Washineon
2
Tag recoveries through 1965, from 1,585 tagged Dover s o l e
released i n Area A during 1961 (no r e l e a s e s i n Area B
during 1961).
8
....................................................
.................................................
3.
4.
5
6.
Tag recoveries through 1965, from 2,504 tagged Dover s o l e
released i n Area A and 304 released in Area B during 1962..
...
Tag recoveries through 1965, f r m 1,660 tagged Dover s o l e
released i n Area A and 242 released in Area B during 1963...~
10
Tag recoveries through 1965, from 947 tagged Dover sole
released i n Area A and 1,771 released i n Area B during 1964..
11
Dover s o l e t a g recoveries by depth tagged and recovered
expressed a s a per cent of t o t a l t a g s recovered
..............
Per cent of Dover s o l e tagged and recovered by depth of
tagging
......................................................
8,
Length-f requency d i s t r i b u t i o n of tagged Dover s o l e by year
of tagging . . . , . . . . . . . . . . . . a ~ . O O D . . . . . . . . . . . o . . . . . . . . ~ . . . . . . . o
3,
Length-frequencv d i s t r i b u t i o n of tagged Dover s o l e and per
cent recovered by centimeter groups through 1965.
10.
............
Average s i z e by sex of Dover s o l e by 25-fathom depth
i n t e r v a l s , Augerst 26-September 1, 1962 and August 19September 6, 1963 samples combined....,.......
...............
11.
A v e r a ~ es i z e by sex of Dover sole by 25-fatham depth
i n t e r v a l s , May 4-19, 1963 and May 12-19, 1964 samples
combined......
...............................................
12.
Number of Dover s o l e tagged by 250-fathom depth i n t e r v a l s
and per cent of males occurring i n untagged samples f o r
periods (A) May 4-19, 1963; (B) Aug. 19-Sept . 6, 1963;
(c) Nov. 2-3, 1962; and ( D ) Nay 12-19, 1964..
................
13.
9
Dover s o l e catch-per-hour by 25-fathom depth i n t e r v a l s f o r
1961-63.
.....................................................
LIST OF TABI;ES
Page No,
Table No.
1.
Numbers of Dover s o l e tagged June 1961 -May 1964 by depth
and time of tagging, and percentage recovery through 1965..
...
-
3
Numbers of s a b l e f i s h tagged May 1962 May 1964 by depth
and time.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . o . . . . . . . . . . . . . o
5
3.
Numbers of Dover s o l e recovered by y e a r of tagging and
recovew................
7
4.
Dover s o l e landings in 1961 a t Astoria f o r PMFC a r e a s 2 4
(northeni half) and 2-D, showing a r e a , month, and depth of
catch
15
Dover s o l e landings i n 1962 a t Astoria f o r PMFC a r e a s 2 4
(northern h a l f ) and 2-D, showing area, month, and depth of
catcho
16
Dover s o l e landings i n 1963 a t A s t o r i a f o r PMFC a r e a s 2 4
(northern h a l f ) and 2-D, s h o d n g a r e a , month, and depth of
~atch~~..~....
17
Recoveries of tagged Dover s o l e by depth and month, 1961
through 1965.
18
2.
......................................
.........................................................
5.
........................................................
6.
...............................................
7.
8,
9,
.................................................
T a g r e c o v e r i e s b y s e x a n d y e a r t a g g e d .........................
26
Nwnbers of s a b l e f i s h tagged and recovered by year of tagging
and recovery..........
29
......................................
INTRODUCrION
The disposal of radioactwe waste products i s a serious problem facing
s c i e n t i s t s and the public.
One solution proposed i s t o dump these waste products
a t sea, with t h e area off northern Oregon and southern Washington i n 100 t o 1,000
fathoms a s one area of consideration.
However, one of t h e problems t o be resolved
i s t h e subsequent d i s t r i b u t i o n of f i s h e s present i n t h e area where t h e s e wastes
would be dumped.
Do these f i s h move inshore t o become available t o f i s h e r i e s
and hence u t i l i z e d by man?
The most p r a c t i c a l method present ly available t o determine the migration of
these deep water f i s h e s i s by tagging.
Recoveries of tagged f i s h by t h e inshore
f i s h e r i e s would provide information on t h e offshore-inshore movements of these
fish.
T h i s is t h e f i n a l report on a cooperative study by t h e Atomic Energy
Commission (AEC), Bureau of Commercial Fisheries (BCF), and Oregon Fish
Commission (OFC) t o det ennine t h e off shore-inshore movements of Dover s o l e
(~icrostomuspacificus) and sablef i s h ( Anoplopoma f imbria )
.
Funds f o r t h i s
study were made available from t h e AEC on a yearly contractual basis.
This
report w i l l present t h e methods, materials, r e s u l t s , and conc:~usions of the
work accomplished since i n i t i a t i o n of t h e study i n June 1961.
METHODS AND MATERIALS
During t h e period from June 1961 t o May 1964, 9,013 Dover sole and 4,647
sablefish were tagged and released a t approximately 25-fathom i n t e r v a l s from
50 t o 450 fathoms i n a 35-mile-long area southwest of t h e Columbia River
(Figure 1).
The tagging was done f m m t h e BCF vessel John N. Cobb and BCF
chartered vessel Conmando.
The dates, depth, and numbers of f i s h tagged and
released a r e shown in Tables 1 and 2.
Figure 1.
Area of investigation o f f northern Oregon and
southern Washington,
Table 1. Numbers of Dover s o l e tagged June 1961 -May 1964 by depth and time of tagging, and percentage
recovery through 1965,
L7UA
6-6 t o 6-9
No
% Re-
9-11 t o 9-17
A 7UL.
.
12-6
Depth
o
No,
5 Re- No. % Re(fhs) Tag,yed eovered Tagged covered Tqged covered
'-3-3to3-12
5-18to5-5.
-8-26to9-1
U-2toU-3
No,
46 ReNo,
% ReNo,
%ReNo,
7 ReTagged covered Tagged covered Tagged covered Tamed covered
13
0
35
2. 9
64
42
19.0
I40
6.4
lo0
0
1,0
6.
F i s h t o be tagged were taken with a 400-mesh commercial otter-trawl net with
13-inch mesh l i n e r in t h e cod-end, and t h e tows were of 0.4 t o 1,l hourqs duration,
A t t h e end of a tow, t h e catch was s p i l l e d on the deck and 100-300 viable Dover
sole o r 50-150 s a b l e f i s h were sorted i n t o a l i v e tank.
by t h e vessel"
pump.
Fresh seawater was supplied
Two types of t a g s were used f o r Dover s o l e - 5/8-inch
fluorescent orange Petersen d i s c s with soft-tempered s t a i n l e s s s t e e l pins and
8-inch orange double-barb d a r t t a g s of v i n y l tubing.
Six-inch vinyl p l a s t i c dart
t a g s with nylon single-barb heads were used f o r tagging black cod.
The tagged f i s h were brought i n a s p a r t of t h e catch of t h e commercial
trawlers and, in t h e case of sable f i s h , occasionally longliners,
The t a g s were
g t h e f i s h processing plants i n t h e Astoria and
recovered by d a i l y c ~ ~ n v a s s i nof
Warrenton areas and interviewing t h e v e s s e l skippers and fishermen a s they
unloaded,
Since the t r a w l vessels unload bottom f i s h a t s e v e r a l ports along t h e
Oregon coast and t h e p r o j e c t b i o l o g i s t was stationed a t Astoria, it was necessaw
t o t r a v e l t h e coast a t approximately monthly i n t e r v a l s t o pick up t a g s and gather
A s an incentive f o r fishermen and f i l l e t e r s t o return a l l t a g s , a
catch data.
reward of
$ 0
50 t o $, 75 per t a g , depending on t h e amount of recovery information
available, has been paid s i n c e 1962.
Whenever possible, t h e complete tag-
bearing f i s h was recovered along with t h e date of recovery, location, an8 depth
of catch,
When t h e specimen was returned t o t h e laboratory, s c a l e s and o t o l i t h s
were removed f o r age analysis, length recorded f o r growth s t u d i e s , and t h e s e x
recorded,
RESULTS
During t h e period June 1961 t o December 31, 1 ~ 6 755
5 ~ Dover s o l e and 19
s a b l e f i s h t a g s were recovered.
a r e shown i n Table 3,
Recoveries of Dover s o l e t a g s by year of tagging
The r e t u r n s f r m s a b l e f i s h tagging have been negligible;
therefore, most of t h e time and e f f o r t has been d i r e c t e d toward Dover s o l e ,
Table 3,
Numbers of Dover .sle recovered br year of tagging and
recmepg.
Year of
tagging
Number
tagged
1961
TOT A .
9,013
9
Recoveries by Year
1962
1963 1964
80
113
349
% of t a g s
1965
219
Total
recovered
770
8.5
Although it was anticipa$ed t h a t a computer program would be used f o r t h e f i n a l
analysis, the shortage of time byought about by t h e termination of t h e c o n t ~ a c t
made t h i s impossible.
Dover Sole
movements of Dover sole,
I n order t o b e t t e r understand t h e eL ,i-~~;.i;c-=-hshore
the area of tagging has been divided i n t o two zones a s i l l u s t r a t e d in Figure 1.
Area B represents t h e shallow pelease zone, 35 t o 90 fathoms, and Area A represents t h e release zone from 90 t o 450 fathoms,
A grid pattern, placed a t 1 0 4 l e
i n t e r v a l s e a s t from 125' West longitude and along each 100 microsecond loran
bearing l i n e from 2H4 2600 t o 2H4 3800, has been drawn over t h e e n t i r e area of
t a g recovery.
These squares a r e a p p r o x h a t e l y 8 by 10 miles and, although l a r g e
enough t o n u l l i f y minor e r r o r s which may have occurred in t h e reported location
of t a g recovery, a r e small enough t o show the general pattern of movement.
When
t h e recoveries from each year% tagging a r e assigned t o t h e i r area of return
( ~ i g u r e s2, 3, 4, and 5), a general noPtheast and inshore pattern of movement can
be seen f o r the deep water releases ( ~ r e A]a returned during t h e summer and e a r l y
f a l l ( ~ a yt o ~ o v e m b e ~ ) .Tag returns from Area B f o r t h e same period show e f t h e r
some inshore movement o r no movement.
Although t h e number of recoveries during
Figure 3 .
Tag recoveries through 1965, from 2,5a tagged Dover s o l e released
umbers i n
i n Area A and 304 released i n Area B during 1962.
upper r i g h t corners of each square a r e those recoveries from
Area B; Area A recoveries are : l+J-!cated i n lower l e f t corner.
Circle6 numbers i n d i c a t e tags recovered from November t o May;
a l l others were recovered from May t o November. )
I
PO,
Figure 4.
Tag recoveries through 1965, from 1,660 tagged Dover sole released
i n Area A and 242 released i n Area B during 1963. (Numbers i n
u p p r r i g h t corners of each square a r e those recoveries from
Area B; Area A recoveries a r e indicated i n lower l e f t corners,
Circled numbers indicate t a g s recovered from November t o May;
a l l others were recovered from May t o November. )
.@re 5.
Tag recoveries through 19659 from 947 tagged Dover s o l e released
i n Area A and 1,771 released i n Area B during 1964. ( ~ w n b e r sin
upper r i g h t corners of each square a r e those recoveries from
Area B; Area A recoveries a r e indicated i n lower l e f t corners,
Circled numbers indicate t a g s recovered from November t o May;
a l l others were recovered from May t o November, )
->
A&.
-1
t h e winter and e a r l y s p r i n g (November t o May) i s much smaller, Area B r e l e a s e s
i n general show a n opposite southwest movement t o deeper offshore a r e a s ,
A recoveries during t h i s period show l i t t l e o r no movement,
Area
Although a few t a g s
were recovered in Willapa Deep and a s f a r south a s Cascade Head, such movements
were minimal, and no major north o r south migration i s shown,
Figure 6 shows t h e t a g recoveries by depth of r e l e a s e and recovery f o r each
year.
The recovered f i s h show a d e f i n i t e movement t o shallower water.
It i s
apparent that a very high percentage of t h e t a g s a r e returned in t h e depth range
of 25 t o 100 fathoms,
The p e r cent recovery by depth of tagging (Table 1 ) has been g r a p h i c a l l y
presented i n Figure 7,
fathoms o r l e s s ,
A higher recovery r a t e i s shown f o r f i s h released in 100
I f we c o r r e l a t e monthly Dover s o l e catch p a t t e r n s by depth from
t h e northern h a l f of P a c i f i c Marine F i s h e r i e s Cornmission Area 2 4 and a l l of Area
2-D (Figure 1 ) with t a g r e t u r n s by depth tagged, a p a r t i a l explanation f o r t h e
tagging depth and per cent recovery r e l a t i o n s h i p i s obtained,
About 8 s of t h e
Dover s o l e landed from t h e northern h a l f of PMFC Area 2 4 and a l l of Area 2-D f o r
t h e period 1961-63 ( ~ a b l e s4, 5, 6 ) were caught in l e s s thari 90 fathoms, while 86%
of t h e t o t a l recoveries were from 100 fathoms o r l e s s .
I n addition, over 75% of
t h e y e a r l y landings from 1961-63 were made from May through Septembep and over 85%
of t h e t a g s were recovered duping t h i s same period
a able 7).
It i s apparent,
t h e r e f o r e , t h a t t h o s e f i s h tagged and released in l e s s than 100 fathoms during
May o r June of any one y e a r would be subjected t o an i n t e n s e fishery.
This
p a r t i a l l y explains t h e high recovery r a t e f o r 1964 when 1,347 r e l e a s e s were made
a t 50 fathoms f n May of t h a t year,
A s noted e a r l i e r , t h e percentage r e t u r n f o r deep-water r e l e a s e s has been low
a able
1 ) compared t o t h e percentage r e t u r n f o r shallow r e l e a s e s .
has been o f f e r e d f o r t h e higher r e t u r n r a t e f o r shallow releases.
One explanation
However, i f
Dover s o l e do migrate inshore and offshore, a s has a l r e a d y been suggested, t h e n
O
-.
----
200
250
300
350
400
Depth in Fathoms
Recoveries by depth recovered expressed as a per cent of total recoveries,
Recoveries by depth tagged expressed as a per cent of total recoveries,
-
50
100
150
Figure 6, Dover sole tag recoveries by depth tagged and recovered expressed
as a per cent of total tags recovered, (The depth of recapture is
not known for all recoveries this explains the difference in N. )
-
I
30 t
-
Fish Tagged N = 1585
N = 42
-- F i s h Recovered
I
'
20
1
0
1
1962
- Fish Tagged
-- Fish
- Fish
--
N = 2808
Recovered N = 220
I
1963
Tagged N = 1903
F i s h Recovered M = 62
___
i
1964
- Fish Tagged N = 2718
Fish Recovered M = 446
I
--
I
I
Ii
I
i
- --------I-----(
400
.
0
----
150
200
250
300
350
Depth in Fathoms
Fish tagged by depth expressed a s a per cent of t o t a l number tagged.
Fish recovered by depth expressed a s a p e r cent of number tagged a t t h a t
depth.
Figure 7,
50
100
Per cent of Dover s o l e tagged and recovered by depth of tag69ng.
Table 4.
Month & Area
Dover s o l e landings i n 1961 a t Astoria f o r PMFC a r e a s 2-C (northern
h a l f ) and 2-D, showing area, month, and depth of catch,
(Landings i n thousands of pounds, )
0-30
30-60
January
2 -D
N, Half 2-C
-
1
February
2-D
N. Half 2 4
-
-
March
2-D
N. Half 2 4
April
2-D
N, Half 2-C
May
2-D
PJ, Half 2-C
June
2-D
-
60-90
-
-
5
-
-
-
-
-
-
-
-
5
--
-
-
30
-
11
-
114
17
52
11
8
-
152
M. Half 2-C
-
102
9
July
2 -D
N.Hqlf2-C
31
-
91
2
49
August
2-D
N, Half 2-C
19
3
59
3
151
September
2-D
N. Half 2-C
9
October
2-D
N. Half 2-C
-
November
2 --D
N. Half2-C
-
December
2-D
N. Half 2-C
-
6
-
180-230
-
g
g
-
-
150-180
-
-
-
-
Depth (Fathoms )
90-U0 '120-150
-
-
g
-
-
Total by
Month & Area
6
-
-
-
-
-
1
2
12
20
-
-
-
-
,
Table 5,
Month & Area
January
2-D
N. Half 2 4
February
2-D
N, Half 2-C
Dover s o l e landings i n 1962 a t Astoria f o r W C areas 2-C (northern
h a l f ) and 2-D, showiqg area, month, and depth of catch,
( ~ a n d i n ~i n
a thousands of pounds, )
0-30
-
-
-
Ma~ch
2 -D
N, Half 2-C
-
Apri 1
2-D
-
N, Half 2 4
June
2 -D
-
5
N,Half2-C
-
July
2pD
FJ-Half24
18
August
2-D
27
-
N, Half 2-C
-
September
2-D
N, Half 2-C
26
O c t aber
2-D
N. Half 2-C
November
2 -D
N, Half 2-C
December
2-D
N o Half 2-C
TOTAL
r ,
1
-
-
-
-
105
30-60
--
60-90
-5
Depth (Fathoms)
90-120 120-150
--
--
150-180
--
180-230
12
-
~ o t a byl
Month & Area
17
-
Table 6.
Dover s o l e landings i n 1963 a t Astoria f o r PMFC a r e a s 2-C (northern
h a l f ) and 2-D, showing area, month, and depth of catch.
a an dings in thousands of pounds. )
4
Depth (Fat horns )
Month & Area
0-30
January
2-D
N. Half 2 4
February
2-D
N. Half 2 4
March
2-0
tu'. Half 2-1:
May
2-D
N. Half 2-C
June
2-D
8
-
10
W . Half 2-C
-
July
2-D
N e Half 2 4
15
August
2-D
N. Half 2 4
14
September
2 -D
N.Half2-C
4
Oet ober
2-43
N. Half 2-C
2
November
2-D
N. Half 2-C
-
December
2-D
N. Half 2-C
-
TOTAL
-
-
2
-
56
30-60
60-90
90-120
120-150
150-180 180-230
T o t a l by
Month & Area
m
t-i
s
(
'a
r
Eo
4
n
N
4
l
0 \ a
1
l
I
I
I
I
r
I
n
I
l
N
t-i
ri
*
00'
t-i
ECm
rn
t-i
19
4
those f i s h tagged i n deep water should become a v a i l a b l e t o t h e f i s h e r y ,
Only 2.3%
of t h e 4,540 f i s h r e l e a s e d a t depths over 100 f athorns has been recovered.
4,473 f i s h tagged i n 100 fathoms o r l e s s ,
U.5%has been recovered.
Of t h e
What a r e t h e
reasons f o r t h i s d i f f e r e n t i a l a v a i l a b i l i t y ?
Length-frequency d i s t r i b u t i o n s by y e a r of t h e tagged f i s h a r e shown in
Figure 8.
Although t h e d i s t r i b u t i o n s show small v a r i a t i o n s from year t o year,
they a r e very co31parable.
The 1961 f i s h , which were tagged from 100 t o 400
fathoms, have a l a r g e r modal s i z e than t h e 1964 f i s h , which were mostly tagged
a t l e s s than 100 fathoms.
F i s h tagged during 1962 and 1963 were from both shallow
and deep a r e a s .
A composite p i c t u r e of t h e length-frequency d i s t r i b u t i o n s of a l l tagged f i s h
and per cent recovered by centimeter group i s shown i n Figure 9.
The per cent
recovered i n c r e a s e s t o a high a t 42 centimeters a f t e r which f l u c t u a t i o n s in t h e
recovery r a t e a r e probably caused by t h e small numbers of f i s h tagged,
It i s
apparent t h a t s m a l l e r Dover s o l e have l e s s chance of being recovered and t h a t t h e
length-frequency d i s t r i b u t i o n of each group of tagged f i s h has some influence on
t h e per cent recovered.
However, f i s h tagged in deep water (100-400 fathoms,
1961 d a t a , Figure 8) a r e o f s i m i l a r o r l a r g e r s i z e than f i s h tagged i n shallow
water (50-75 fathoms, 1964 data, Figure 8).
?
Since Dover s o l e cannot be sexed e x t e r n a l l y , t h e sex r a t i o s of tagged f i s h
a r e unavailable.
However, on s e v e r a l occasions, f i s h l e f t over a f t e r tagging
had ceased were sexed.
Figures 1 0 and 11 show t h e average s i z e by depth and sex
of f i sh t h a t were not tagged.
I f we assume t h a t t h e untagged f i s h a r e of t h e
same s i z e and s e x composition a s tagged f i s h , then a d e f i n i t e increase in average
s i z e a s depth i n c r e ; s s i s shown.
Therefore, t h e d i f f e r e n c e i n a v a i l a b i l i t y cannot
be explained by a s i z e d i f f e r e n t i a l .
The per cent of males occurring i n t h e s e samples i s shown g r a p h i c a l l y by
depth i n Figure 12.
The percer?t%geof f i s h tagged by depth i s a l s o shown.
20
Figure 8,
25
40
45
50
55
60
Length i n Centimeters
Length-frequency d i s t r i b u t i o n of tagged Dover s o l e by year of tagging.
30
35
t o t a l tagged (N =
Q)
I%
L
?I-
40
50
Length in Centimeters
Figure 9,
Length-frequency d i s t r i b u t i o n of tagged Dover s o l e and p e r cent recovered by
cent h e t e r groups through 1965
150
Figure 10,
200
250
300
Depth i n Fathoms
350
400
450
Average s i z e by sex of Dover s o l e by 25-fathom depth i n t e r v a l s , August
September 1, 1962 and August 19 September 6, 1963 samples combined,
-
-----
r
A*-*
24.
1
May 4-19, 1963
k
I
I
r
I
r
[
-
Ii
A
I - - - -
$ Hales
-f- -
/ Fish Tagged
-
50
/
100
150
------
200
250
300
Depth i n Fathoms
--- -
-
3 50
-
- --
400
- -
450
-- --
B.
% Males
Aug, 19-Sept. 6, 1963
4
5
1
U
1
&
1
Q)
Fish Tagged
N=8U
20
i
i
I
I
50
100
Figure 12.
150
200
250
300
Depth i n Fathoms
I
I
350
400
450
Number of Dover s o l e tagged by
, -fat!.?:~~n
dcpt,,ii int~rvdls~ t per
~ d
cent of males occurring i n untag&ed samples f o r periods ( A ) iwlay4-19,
1963; (B) Aug. 1 9 S e p t . 6, 1963; (c) Nov. 2-3, 1962: and (D)
May 12-19, 1964.
.
90
...~...
-
--
-..-
.. -..
-
-..
-
-
~
~
--.
-. ,.
.,-. -
- -.
-. ..
. . ..
.
. ....
C
1
d
Nov. 2-3, 1962
1
r
I
I
/
h
1
10
i
I
!
50
100
150
200
250
300
Depth i n Fathoms
350
400
I
450
May 12-19, 1964
50
100
150
Figure 12 continued.
200
250
300
Depth in Fathoms
3 50
400
450
26,
No s e x r a t i o s were taken during t h e 1961 tagging c r u i s e s ,
One t r i p was sampled
during 1962 with approldmately 1C$ of t h e t o t a l f i s h tagged during 1962 being
tagged on t h i s t r i p ,
Samples were taken during 1963 and 1964 from t r i p s repre-
s e n t i n g over 9C$ of t h e t o t a l f i s h tagged f o r each year.
Except f o r t h e two
samples taken a t 375 and 400 fathoms, during August and September 1963, t h e per
cent of males shows a d e f i n i t e increase beyond 100 fathoms.
Hagerman (1952)
reported t h a t during t h e summer males comprised most of t h e catch from deep water.
It i s apparent t h a t those f i s h tagged in deep water during 1963 were mostly
males ( ~ i ~ u 1r 2e A and B).
The f a c t t h a t t h e recovery r a t e f o r deep water r e t u r n s
was low would suggest t h a t most of t h e males do not migrate i n t o t h e inshore areas
of high f i s h i n g i n t e n s i t y .
Further evidence of t h i s i s founb in t h e sex r a t i o s
of t h e recoveries a s shown i n Table 8.
Table 8,
Year
tagged
Although more male4 we*
tagsc-d
in 1963,
Tag recoveries by s e x and year tagged.
Males
recovered
Female s
recovered
Unknown
Total
TOTAL
over twice a s many females were recovered.
Although t h e sex camposition of t h e 1961 tagged f i s h i s unknown, it i s
probable t h a t t h e per cent of males was higher than in 1963.
A l l of t h e 1961
tagging was done a t 100 fathoms o r more, and most a t 200 fathoms o r g r e a t e r ,
Data presented i n Figure 12 and t h e findings of Hageman (1952) would suggest
t h a t mostly males a r e found a t those depths where most of t h e tagging took place,
27'*
It i s i n t e r e s t i n g t o note t h a t more males than females were returned from t h e
1961 r e l e a s e s (Table 8 ) .
From t h i s irr.9, * .<ez
evidence, we can surmise t h a t t h e
1961tagged f i s h were mostly males and, a s evidenced by t h e recovery r a t e , most
of t h e males did not migrate inshore.
I!nfortunately, no d i r e c t evidence i s
available.
These f i n d i n g s agree with t h o s e of Hagerman (1952) and Westrheim and Morgan
(1962) who reported t h a t most of t h e males probably did not migrate onto t h e
inshore grounds.
The 1962 and 1964 tagged f i s h and recoveries present somewhat d i f f e r e n t
pictures.
Very l i t t l e s e x r a t i o d a t a a r e a v a i l a b l e f o r t h e 1962 tagged f i s h , but
approximately 5@ of t h e f i s h were tagged a t 100 fathoms o r l e s s with moat of t h e
remaining f i s h tagged between 150 and 275 fathoms.
I f we assume, a s suggested by
t h e 1963 d a t a , t h a t t h e inshore f i s h were rqoatly females and t h e offshore f i s h
mostly males, then t h e recovery p a t t e r n shown i n Figure 6 i s again explained by
t h e lack of male migration t o inshore areas.
Approldmately
5019 of t h e f f sh taqged
during 1964 were r e l e a s e d a t 50 fathoms and over 904k were released i n 100 fathoms
o r less.
A s shown i n Figure 12 D, most of t h e f i s h were females.
The recovery
r a t e from t h e s e has been very good,
Catch-per-effort
d a t a by depth (Figure 13) from tows made within t h e tagging
a r e a during t h e e a r l y and l a t e summer of 1961-63 show two concentrations of Dover
s o l e (~eyamotoand Pereyra, 1962; Heyamoto, Pereyra, and A l t on, 1964).
Although
t h e a v a i l a b l e sex r a t i o d a t a f o r 1961 and 1962 a r e inadequate f o r ' d e t e ~ m i n i n ~
t h e composition of t h e s e eoneentrations, t h e 1963 d a t a (Figure 1 2 A and B ) show
t h a t t h e inshore concentrat ion was most ly females and t h e o f f shore concent r a t ion
was l a r g e l y males.
Sable f is h
Of t h e 4,647 s a b l e f f s h tagged over a three-year period
have been returned.
a able
2), only 19
The recoveries by y e a r of tagging a r e shown in Table 9.
lOO0-
-June
--June-July
'.
....... Sept
.
500 -.
I
,i
0.
/
/
.,
'
L:
,:-
I
j
?
,
.
1962
-May-June
--- Aug
/
'.
\
100
.
-Sept,
\
/
-.+
50
, .,?,.---T.?..<>............?/-
-7
200
~-
-. -
-.
250
300
350
400
- . .
450
Depth in Fathoms
Figure 13, Dover sole catch-per-hour by 25-fathom depth intervals f o r 1961-63.
(From Heyamoto and Pereyra, 1962.;Heyamoto, Pereyra, and Alton, 1964).
Table 9.
Year of
t agging
Numbers of sablefish tagged and recovered by year of tagging
and recovery,
Number
tagged
1961
Recoveries by year
1962 1963
1964
% of Tags
1965
The movements of sablefish have varied greatly.
Total
recovered
Of t h e 17 peturns from
which recovery data a r e known, f i v e have moved more than 25 miles from t h e area
of tagging; one went 120 miles north fn f o u r months; two went approxfnately 75
miles south; and two others went 275 miles south.
The recovery r a t e of
0 ~ 4 %i s
inadequate t o draw any general conclusions regarding movements.
Sablefish tagging studies conducted in Washfngton, Oregon and California
i n 1950 and 1951 produced r e l a t i v e l y low recoveries.
The recovery r a t e s f o r
each s t a t e , approximately two years a f t e r i n i t i a t i o n of t h e studies, were a s
follows:
1954).
California 3.2%; Washington 2,%; and Oregon 1,5% (~olmbergand Jones,
A t t h a t t h e , t h e Oregon f i s h e r y was operating a t a low level.
The low number of recoveries can probably be a t t r i b u t e d t o several f a c t o r s ,
but t h e major reason appears t o be t h e lack of f i s h i n g e f f o r t in t h e deeper
waters where most of t h e marketable s a b l e f i s h a r e found.
been made from t h e minor Oregon long-line fishery.
No recoveries have
Most of t h e f i s h recovered
have been those caught i n c i d e n t a l l y i n t h e trawl catches,
,Since most of t h e
l a r g e r sablefish a r e found a t depths from 250 t o 450 fathoms, t h e f i s h a r e not
sought by l o c a l t r a w l f f shermen a t t h e present time.
A complete presentation and discussion of t h e d i s t r i b u t i o n , abundance, and
30,
s i z e of sablefish found in deep water off t h e mouth of t h e Columbia River has
been publf shed by Heyamoto and Alton (1965).
SUMMARY
A cooperative study was i n i t i a t e d i n June 1961 by t h e Atomic Energy
Commission, Bureau of Commercial Fisheries, and Oregon Fish Commfssion t o
deternine t h e offshore-inshore movements of Dover sole and sablefish,
During t h e period from June 1961 t o May 1964, 99013 Dover s o l e and 4,647
sablef ish were tagged and released a t approximately 25-fathom fnt ervals f ram
50 t o 450 fathoms in a 35-mile-long area southwest of t h e Columbia River.
Tagged f i s h were brought i n a s part of t h e catch of t h e commercial trawlers,
Returns of tagged Dover sole show a n o d h e a s t e r l y and inshore movement
during t h e l a t e spring and e a r l y surtuuer.
An opposite movement t o offshore
areas is ahown during the l a t e f a l l and e a r l y winter.
A higher recovery r a t e was found f o r Dover s o l e tagged
tha
f a r those tagged i n deeper areas.
d i f f e r e n t i a l recovery rate:
in shallow water
Two factors appear t o explain t h i s
(1) t h e f i s h e r y i s most intense i n t h e shallow
areas during the summer; and (2) most of the deep-water tagged f i s h were males
an, t ; , imles
~
do not move as f a r inshore as do t h e females.
No difference i n
a v a i l a b i l i t y of deep-water tagged f i s h and those tagged in shallow water could
be a t t r i b u t e d t o size.
Of the 4,647 sablefish tagged, only 19 were returned.
The recovery r a t e
is inadequate t o draw any general conclusions regarding movements.
The low
number of recoveries can probably be a t t r i b u t e d t o several f a c t o r s , but t h e
major reason appears t o be t h e lack of fishing e f f o r t in t h e deeper waters
where most of t h e marketable sablefish a r e found.
LITERATIrEZe CITED
APverson, D.L.
1960. A study of annual and seasonal bathymetrie catch
patterns f o r commercially important groundf ishes of the Pacific
northwest coast of North America. P a c i f i c Marine Fisheries Comm.
Bull. 4. 66 p.
Hagennan, F.B. 1952. The biology of t h e Dover sole (kie~ostvmuspacificus)
(~ockington). Calif. Dept. of Fish & Game Bull. 85,
Harry, G.Y. 1956. Analysis and history of t h e Oregon o t t e r trawl fishery.
Univ. of Wash. Ph.D. t h e s i s . 328 p.
Heyamoto, H., and W.T. Pereyra. 1962. Deep-water marine explorations.
Progress Report No. 1. January 1 December 31, 1961. U,S. Atomic E n e r a
Cam. Agreement ~~(49-7)-1971-ModificationNo, 1:l-10.
-
Heyamoto, H., W.T. Pereyra, and M.S. Alton. 1964. Deep-water marine
explorations. Progress Report No. 5. July 1, 1963 December 31, 1963,
U. S . Atomic Energy Corn. Agreement ' ~~(49-7)-197l+odff i c a t f on No, 1:1-13,
-
Heyamoto, H., and M.S. Alton. 1965. Distrfbutf on, abundance, and s i z e of
sablefish (A.noplopoma fimbria) found in deep water off the mouth of t h e
Columbia River. Comnercial Fisheries Review 27(11)2 1 - 8 .
Holmberg, E. K. , and W. G. Jones. 1954. Results of sablefish tagging experiments
i n Washington, Oregon, and California. Pacific Marine Fisheries Comm.
Bull. 3: 103-119.
Westrheim, S . J . , and A. R. Morgan. 1963. Results from tagging a spawning stock
of Dover sole, Microstomus pacificus. Pacific Marine Fisheries Comm,
Bull. 6~13-21,
,