~.
i.
,
Inlernalional Council ror
C.H. 1992/G:22
lhe Exploralion
Demersal Fish Cammillee
o~
lhe Sea
A comparison or Lhe growLh raLe i~ walleye pollock
(Theragra chalcogramma) ~aken rrom Lhe open waLers or
Lhe Bering Sea and Lhose rrom ~he open waLers
or Lhe OkhoLsk Sea in 1991.
Kowalewska-Pahlke
Sea Fisheries Inslilule
81-332 Gdynia, Koll~laja 1
POLAND
t~gdalena
•
A B S T R A C T
The growlh o~ walleye
pollock
(Theragra
chalcogramma) rrom lhe inlernalional walers o~ lhe
Bering and Okholsk Sea was examined in 1991.
Hean
lenglh al age o~ pol lock was dislincly higher in
lhe Bering Sea lhal in lhe Okholsk
Sea.
A
comparison o~ lhe von Berlalanrry's growlh curves
indicaled dirrerences in growlh belween lhe lwo
regions. These dir~erences are expressed by lhe
L-inr and K paramelers, ror bolh males and remales.
Con~idence limils
ror lhese lwo paramelers are
dirrerenl and do nol overlap.
The lesl o~ lhe
hypolheses concerning lhe dirrerences belween maens
lenglh al age o~ pol lock rrom lhe -inlernalional
walers or lhe Bering and Okholsk Sea also indicaled
slgniricanl dirrerences belween lhese lwo regions.
•
I N T ROD U C T ION
Pollock (Theragra chalcogramma) is a species dislribuled over
wide
area
or
lhe
Norlh
Paciric.
conlinenlal slope rrom lhe Sea or
Il
Japan
occurs
lhrough
on
lhe
lhe
shelr
Okholsk
a
and
Sea,
Bering Sea and Gulr or Alaska,lo Vancouver. Il has been belived unlil
recenlly lhal lhe species lives
ne ar
lhe
boltom
it
however, lhal subslanlial pollack slocks occur also in
turned
deep
out,
walers,
.,
.
~he
especially in
or/~his
stocks
45 M.
~ons.
Bering Sea, leading
~he
species in
~he
and
a pelagic mode or
es~imated
North Paciric are
catches
in
reached
1989
living.
6 259
a~
The
about
~hous
~ons
ex~rac~ed
rrom
I
CYearbook 1990).
~he
abou~
Bering Sea and
recent years
species
~his
in
and
large
eas~ern
populations are
less visible.
been:~he
gene~ic
Okhotsk
~he
Sea.
In
greatest single-
pollock
be~ween
North
~he
Paciric
Genetic dirrerences
regional
al~hough
~he
in
object or
dirrerences
or
isola~ed.
. were
world rishery.
~he
parts
~hous ~ons
~hous ~ons
1 800
species has
exploi~ation
Rela~ively
wes~ern
or wh ich 3 713
ou~
show
rrom
~ha~
wi~hin ~hese
dirrerences
in
grow~h
~he
~hese
areas
are
ra~e.
age
•
composition. meristi~ and morphometric rea~ures occur ~here.
biology and stocks or pol lock in
Al~hough ~he
rela~ively
weIl known.
Sea. The objective or
composition or the
waters or
growth between
~Iaterials
in 1991,by
the
pol lock
stock
exploi~ed
Okho~sk
~he
to
were
rrom
~he
otoliths were removed rrom 3001
Bering
rish were measured and
otoli~hs
ror
pol lock
In
and
were removed rrom
age
a
split
visible
accepted according
reccomenda~ions o~
Sea
in Gdynia.
In
or
~he
on
~he
and
pollock
December.
1801
Hay-
and
international
35
646
individuals.
between
reading.
increments
Okho~sk
January
specimens
interpretation of growth
~he
in
individuals.
Fork length or rish was measured with
served
Insti~ute
Sea,
Okhotsk Sea, between September
~o
age
on Polish rishing vessels
Sea Fisheries
~he
or
collec~ed
waters or the Bering and
interna~ional
otoliths
and
international
~he
Sea and show dirrerences in
August. measurements were made or 39 389
collected
in
leng~h
Okhotsk
11 E T H·· 0 D
~he s~udy
scien~ists
~he
presen~
~he
two areas.
in~Jinational wa~ers
waters or
Bering Sea are
pollock rrom
is
AND
ror
abou~
paper
~hese
tlATERIAL
is known
~his
Bering and
~he
operating in
lit~le
~he
sexes.
The
The
me~hod
and
the
otolith
were
Special
Group
on
Ageing rJethodology or Walleye Pollock. held in Gdynia in 1990 [Report
2
•
,
~rom
~he
chalcogramma)~
Areas
o~
1991 are
presen~ed
in
open
~he
wa~ers
according
~he
on
leng~hs
i~~
~o
basis
(Theragra
or
pol lock
~he
conduc~ed
Bering and
by
Polish
~he
Okho~sk
Sea
in
was used
in
~or
calcula~ion
years
subsequen~
or
or
grow~h
are
li~e
eqa~ion:
o~
L~ = L inr
(
*
1 - e -K.
~
(
*
-
~o
»
~
where:
L~
-
leng~h
or
~ish a~
parame~ers calcula~ed
Linr
K. -
~
mean
grow~h
~he
age
on
~~
basis or empirical
~he
da~a:
asymp~o~ie leng~h~
index),
(ca~abolism
coerricien~
de~ermines
shape
~he
or
curve~
LO
~heore~ieal
age~
The
parameLers
or
aL whieh
~his
calcula~ed
In
were
~his
in~rodueed~ assuming.~ha~ ~he
calculaLed
me~hod~
addi~ion,
in
leng~h o~
leng~h
would have a
o~
on Lhe basis or mean lengLhs
by abundaneei
weigh~ed
~he ~ish
equaLion
described by Allen (1966).
•
Pol lock
in Fig.1.
Ber~alanr~y~s me~hod
de~ermina~ed
•
~ishing opera~ions ~or
~lee~
The von
Walleye
1990].
deep-sea
ra~ej
Me~hology o~
Workshop on Ageing
~he
~ish
~heore~ieal
by
o~
0 cm.
meLhod
~he
a~
a
poin~
given
O~
age,
is
O~
age 0 is elose
~ish a~
are
coerrieien~s
~o
0
em.
In order
be~ween
~o
L inr and K. or
examined. An analysis or
me an
leng~hs
~he
signi~ica~ce
popula~ions ~rom ~hese ~wo
pol lock
~or parame~ers
de~ermine
or
~ish
carried ouL
~or bo~h
where: x n
nn
mean
in
~he
~he
age-groups
areas. The rollowing
leng~h.
number in sampie,
3
~he
di~:ferences·
equa~ion
~he di~~erences
or
limi~s
conridence
Ber~alanr~y's
signi:ficance or
same
~he
von
areas.
or
pol lock
s~a~isLies
beLween
was
was used:
were
also
.
".
S2 - variance.
n
For larger'samples (n 1 > 30 and n 2 > 30).
..
re~~ered Lo anormal disLribuLion (2). and
s~a~is~ical
small
~or
values
were
samples
LO
L-SLudenL disLribuLion (L).
c 0 M POS I T ION
L ENG T 11
In Lhe internaLional
lengLhs
wa~ers
the
o~
Bering
Sea
pol lock
34-62 cm. mean being 50.2 cm (Fig.2.3). The main
o~
the sLock (over 75 %) consisLed
o~
rish below 41 cm and
cm
di~~erence
over
55
between mean lengLh
o~
with
~ish
lengLhs
barely
cons~iLuted
males and
3.6
was
~emales
par~
48-53
o~
had
%.
small
o~
cm')
The
(0.5
4t
cm).
In Lhe inLernaLional waLers
lengLhs
o~,11-62
Lhe
o~
cm. mean being 40.9 cm. The main
(60 %) consisLed or rish
Sea
par~
pollock
or
di~~erence be~ween
mean
had
sLock
~he
lengLhs or 39-43 cm; rish below 33
wi~h
over 47 cm consLiLued only 4.5 %. The
o~
OkhoLsk
and
leng~h
males and remales was 1.3 cm.
Mean lengLhs
pollock by sex in sLudy areas in
o~
1991
are
Lhe
~ollowing:
Bering Sea
Okhot.sk Sea
males
49.9 c.
40 . .1 c.
f"e.ales
50.4 c.
41.4 c.
.. & f
50.2 c.
4t
~
~
40.9 c.
Comparing lengLh disLributions
o~
pollack
~rom
Lhe Lwo areas one
may nOLice LhaL Lhe curves have a dicisievly single-peak disLribuLion
and are similar.
~lean
greater by over 9 cm
AGE
The
lengLhs or pol lock
~han
in
~rom
01'
~he
Lhe
Bering
Sea
were
the Okhotsk Sea.
C 0 M POS I T ION
age
considerably in
composi~ion
~he
two areas.
4
L
~ish
~rom
exploi~ed
st.ocks
dirrered
In
waters or
~he in~erna~ional
~he
were present in the stock, with
groups represented by
only
~he
single
Bering Sea 4- to 23-year-olds
oldest
specimens.
13-year old pol lock (year class or 1978);
population occuring in
~he
12 and 11 % or
In
~he
~his
youngest
age
numerous
~Ios~
were
22 % or the
~hey cons~i~ued
area (Fig.4,5) and rish'aged 12 and 14
population, respectively.·
waters
interna~ional
18-year-olds were present. Young
classes or 1986 and 1985)
tt
~he
and
or
rish
Okhotsk
~he
aged
5
and
Sea
6
predominatedi~hey consti~ued
1-
years
~o
(year
26 and
42
%
or the population, respectively (Fig.4,5).
Mean age or pol lock in the
areas was
~wo
~he
Bering Sea
6.3
"10.7
6.1
11.6
6.2
The considerable
remales rrom
~he
Okho1.sk Sea
12.3
aales
:feaales
rollowing:
dirrerence
Hering Sea is a
in
mean
resul~
or
age
~he
between
large
males
abundance
and
or
remales rrom the 1983 and 1984 year classes.
.'
RAT E
GR01'fTH
The
resul~s
or analyses or mean lengths or
age-groups exhibit considerable dirrerences
pollock inhabiting the
~wo
be~ween
areas (Table 1). Mean
rrom the international waters or
age-groups between 5 and 15 years
~he
rish ~"1.n
leng~hs
Bering Sea were
~han
~hose
~he
individual
stocks
or
larger
in rish rrom
~he
or
pol lock
in
all
Okhotsk
Sea.
Growth rate curves calculated on mean lengths in subsequent years
lire
point
CFig.6,7).
to
The
considerable
calcula~ed
dirrerences
values or
parameters have the following form:
5
~he
von
between
the
~wo
Ber~alanrry's
or
areas
equa~ion
.--------------------
----
Okhotsk Sea
Hering Sea
males
..
1'e.ales
..ales
& l'
1'e.ales
.. & l'
51.2
54.3
52.6
44.5
48.4
~
0.3293
0.2814
0.3031
0.47i2
0.3659
0.4357
1. 0
0.0096
0.0062
0.0083
-0.1237
-0.2051
-0.i393
LinC
45.6
The growth or pol lock rrom the Bering Sea is slower than that in
rish rrom the Okhotsk Sea. Approximately at age
or
9
years,
length or about 50 cm, growth is arrested and in later
increments are insigniricant.
In
t.he
Okhotsk
Sea
at
years
the
a
length
growth
or
pollock in t.he rirst years or lire is raster, but at the age or about
7 years it reaches an almost asymptotic lengt.h and its rurther growth
•
. is arrested.
Conridence limits ror the Linr and K parameters or t.he von
Bertalanrry's equation are dirrerent ror rish rrom these two areas
(Fig.8,9). Only ror remales, t.he conridence
limits
or
parameter
K
overlap ror the range or 0.28 1.0 0.30.
The t.ested dirrerence bet.ween mean lengths or rish in
the
same
;i'
age-group turned out 1.0 be signiricant ror the populations studied at
probability p
<
<
and
showed
probability p
remales
0.001, with the exception or age-group 15, ror
0.01.
mean
Testing
the
t.hat
ror males age-gr.oup 5 and
lengths
dirrerences
remales
ror
separately
are
age-group
ror
which
males
insigniricant
12.
This may
be
explained by the large dirrerence in abundance or tested rish between
t.he Bering and Okhotsk Sea.
DIS C U S S ION
A comparison or length and age st.ructure or
the international waters
or
the
Bering
and
pol lock
Okhotsk
distinct. dirferences between t.hese two stocks. Genetic,
and meristic studies (Iwata., 1975
Bakkala et
al,
stocks
Sea
in
reveals
morphometric
1983)
suggested
that the stocks of the Bering and Okhot.sk Sea do not mingle. However,
within
these
stocks
there
6
is
a
number
of
isolated
spawning
•
populaLions.
,
In Lhe Bering Sea, despiLe expending in
research potenLial, Lhe· sLrucLure
clearly
derined
<AFSC
proc.
conLroversy surrounds Lhe
or
Rep.
origin
Lhe
recenL
years
a
pollock
stock
was
91-06,' 1991).
or
Lhe
The
pol lock
large
noL
greatesL
sLock
rrom
Lhe
internaLional waters, where currenL invesLigaLion are cenLred. LengLh
and age composiLion, growth raLe or pol lock
rrom
waters dirrer considerably
pollock
rrom
Lhose
or
Lhe
inLernaLional
inhabiLing
Lhe
shelves or Lhe Bering Sea <Dawson 1988,1990).
•
As regards Lhe OkhoLsk Sea ,Lhere is no agreemenLs eiLher as
Lhe number or
pollock
stocks
inhabiLing
disLinguishes six sLocks, while Fadiejew
Lhis
(1987)
sea.
IwaLa
jusL as with respecL Lo the Bering Sea, there is
(1975)
disLinguishes
spawning stocks only in Lhe norLhern parL or Lhe sea. In
no
Lhis
rive
case,
certainty
which stock rish taken ror examination came. Bakkala (1983)
Lo
rrom
presents
great suscepLibility or spawning stocks to environmenLal changes
Lhe size or the spawning stock. Such
siLuaLion
place in the internaLional waLers or Lhe Bering
had
probably
Sea,
where
very intensive exploitation or the pollock stock distinct
its growLh rate occured <Janusz
1991),
mosLly
as
a
and
taken
due
to
changes in
result
or
a
decrease in reeding competition.
The dirrerences in the strucLure and growth
or
pol lock rrom
the
inLernaLional waters or Lhe Bering and OkhoLsk Sea, presented in this
~~
paper, cannoL b~ treated as
the
only' deLerminanLs
or
independenL
IL may be said, however, thaL there are signiricant
dirrerences
sLocks.
in Lhe growth
or
pol lock
beLween
these
two
areas
expressed
by
parameters Linr and K or Lhe von BerLalanrry's equaLion,
both ror
males and remales. This is conrirmed also by signiricance tesLs
between mean lengLhs or rish in thc same age-group.
R E F E REN CES
Allen K.P.; 1966. A method
or
7
ritLing
growtll
curves
or
the
von
BerLalanrry Lype observed
vol.23.
no 2. 163-179.
,
daLa.
j.
Fish.
Res.
Board.
Can .•
Disscusion Summaries rrom Lhe
AFSC PROCESSED REPORT 91-06.; 1991.
InLernaLional Workshop on Bering Sea Pollock SLock Assessment.
February 4-8. 1991.
Bakkala R.• T. Maeda .• G. McFarlane.; 1983.
DistribuLion and sLock
sLrucLure or pol lock (Theragra chalcogramma) in Lhe NorLh
Paciric Ocean. Unpubl. rep ..• 23p. ~orLh~esL and Alaska Fi~heries
CenLer.Natl. Mar. Fish. Serv .•
NOAA.2725 Montlake Blvd.
E.•
Seattle. WA 98112.
(Document submiLLed to Lhe InLernational
NorLh Paciric Fisheries Commision in OCLober 1983)
Dawson P.; 1988. Walleye Pollack Stock SLrucLure ImplicaLions rrom
Age ComposiLion. Length-aL-Age. and MorphomeLric DaLa rrom Lhe
CenLral and Eastern Bering Sea. Proceedings or the InLernational
Symposium on Lhe Biology and ManagemenL or Walleye Pollock.
Anchorage. Alaska USA.p. 605-642
•
Dawson P.; 1990. InrormaLion on Lhe SLock SLrucLure or Bering Sea
Pollack. CompilaLion or Papers PresenLed aL Lhe InLernaLional
Symposium on Bering Sea Fisheries.
Khabarovsk.
USSR. 1990.
p.65-73
Fadiejew N.• tl.G. Suczkova.; 1987. Raspriedielenie nagulnogo minLaja
na
sjewierie
OChoLskogo
Morja.-Populacjonnaja
sLrukLura.
dinamika czisljennosLi i
sledowia minLaja.
Sbornik naucznych
Lrudow TINRO. WladywosLOk. 1987 p.69
;IwaLaM.; 1975. PopulaLion idenLiricaLion ör walleye pol lock Theragra
chalcogramma (PALLAS). in Lhe vicinity or japan. Memo.
Fac.
Fish. Hokkaido Univ. 22: 193-258
janusz j.; 1991. Impact or PopulaLion DensiLy on GrowLh RaLe or
Walleye Pol lock in Lhe AleuLian Basin. 'BulleLin or Lhe Sea
Fisheries IriSLiLute. No 1-2 (123-124): 22-30. Gdynia 1991
ReporL From The Workshop On Ageing MeLhology or Walleye Pol lock
(Theragra chalcogramma). Held at the Sea Fisheries InsLiLuLe.
Gdynia. 1990
Yearbook or
SLaLis~ics
- FAO or UN, 1990. vol.68
8
•
Table 1. Mean length at age and test for hypotheses
concerning the differences between mean lengths
of walleye pollock from the international
waters of the Bering and Okhotsk Sea in 1991
MLES
:-------------------------------------------------------------------------------------:
Bering Sea
Okhotsk Sea
:--------------:------------:---------------------------:
age
: .ean
: length
t
variance: .ean
: length
:
H.o.
variance:
:
:i:
6:
7:
•
N.a.
40.13
43.47
45.83
8:
47.'14
9:
10:
11:
12:
13:
14:
15:
49.10
49.69
49.52
49.41
49.48
49.83
49.45
2.29
4.10
3.84
3.31
4.51
3.03
4.39
3.97
2.93
3.21
2.75
23
83
120
129
115
100
144
162
352
166
20
:
:
:
:
:
:
:
:
:
:
:
t
I
•
IBB
38.84
41.18
43.10
44.35
45.00
45.45
46.21
45.67
45.08
46.35
45.45
2.48
2.77
2.45
2.05
5.09
4.05
4.27
2.89
3.08
5.69
2.98
183
67
46
22
20
19
18
24
26
11
•
:
p<O.OOl :
p<O.OOl
p<O.OOl
p<O.OOl
p<O.OI
p<0.05
p<0.05
p<O.OOl
p<O.OOl
p<O.Q01:
:-------------------------------------------------------------------------------------:
FEMLES
:-------------------------------------------------------------------------------------;
Bering Sea
Okhotsk Sea
:---------------------------:---------------------------;
.ean
·• length
age
variance: aean
•• length
N.o.
I
I
N.o.
variance:
t
I
.
' _________ : ___________________________ ' _______________- - - - - - - - - - - - ' - - -______ 1 ______ - - - ;
:> :
11
37
97
179
149
120
106
96
124
244
119
40.19
43.29
46.28
49.36
51.20
52.27
52.29
51.99
52.41
52.56
54.38
6:
7:
8:
9:
10 :
I
•
12 :
13:
14:
15 I
2.64
5.13
5.25
6.42
6.49
7.82
7.79
4.78
4.93
3.88
2.73
8
39.35
42.33
44.35
45.70
46.86
48.48
49.14
50.53
49.76
50.15
50.60
2.97
3.24
3.76
5.13
7.15
5.54
7.17 p<O.OOl
13.45
1.24 p<O.OOl
6.57 • p<O.OOl
15.84 : p<O.OI
173
315
132
50
35
31
21
15
17
27
15
p(O.Ol
p<O.OOl
p<O.OOI
p<O.OOl
p<O.OOl
p<O.OOl
I
I
I
I
I
I
I
I
I
I
I
:-------------------------------------------------------------------------------------,
I'IALES Ir FElIALES
:---------------------------------------------------------------------------:
Bering Sea
Okhotsk Sea
:---------------------------:---------------------------:
age
.ean
: length
I
I
variance: .ean
: length
H.o.
variance:
H.o.
I
:---------'---------------------------'---------------------------:---------'
5
6
7
3
9
10
11
40.12
43.37
46.10
48.70
50.17
51.04
50.63
60
180
299
278
235
206
240
2.41
4.61
4.74
5.48
6.62
7.12
7.59 :
39.08
41.91
43.93
45.05
46.14
47.29
47.75
361
498
199
96
57
51
40
2.78
3.38
3.66
4.11
7.17
7.15
7.94
:
:
:
:
:
:
:
p}O.OOl
p}O.OOl
p}O.OOI
p}0.OO1
p}0.QQ1
p}O.OOI
p}O.QOl
12
50.53
28b
5.90 :
47.88
33
13.5b : p>O.OOl
13 :
H:
50.68
50.97
596
285
5.83 :
5.30 :
47.02
48.28
41
53
10.12 : p}O.OOI
9.75 : p}O.OOl
15 :
50.8b
28
7.b9 :
48.42
2b
lb.86 : p>O.Ol
;---------------------------------------------------------------------------.
9
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rv/r':~E
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KIlO T S K
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S E A
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ij "i
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'\ ./
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..
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/~.~.;~:-...\' ~
;."
.:.
..:.::.::::.,.
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.'
i
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.. .t!
-.-.-..
{)
"
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.......... ,............
..... ~'-'-'-'-' ......
.... -,,_.-. .... .....
.,,/
-"-~
._.-
.,-
/
;///
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"",
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)-........
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.I
....."._._. • ~
" ..
;"
.-._._i
, .,....
",
I
'J
i
f
A
/
. /".
./
i.. ,/_ _-J.._ _-J.._ _- - J
'--'-'-'-~~-L.--"':'<:-..L.
l -_ _. 1 -_ _...L-_ _. l -_ _-1-_ _...J-_ _...J
Fig. 1. Sarnpling areas of walleye pollock futhe international waters
of the Hering and Okhotsk Sea
".
in 1991.
4ff'
Length distribution
wal.leye pollack 1991
16..,.--------------------~
14
12
•
-
10
c
~
L.
8
(D
n..
6
4
2
o
'
11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62
Length (ern)
I-+Fig.
c.'
2~
Bering Sea
-B-
Okhock Sea
Length distribution of walleye pollock caught
in the international waters of the Bering
and Okhotsk Sea in 1991 (males and females).
11
-
,..---------------
-
--
--~~
Length distribution
a)
walleye pollack 1991 males
25.----------------------,
20
-c: 15
(iJ
m\
Cl
o
m
I
L
r
~
? b
Cl
a.. 10
p
5
\
q
c;j
o
~
O
•
I
t
•
i.
11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62
Length (ern)
I-+b)
Bering Ses
•
-e- Okhotsk Sea
Length distribution
walleye pollack 1991 femaJes
25.----------------------..,
20
~
--c: 15
1\
rp\
•o
!
ci
i
i
o
r: ':1
I!I
\
\
C!.l
\\
l!J\
/
i
oL
-
.
,
11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62
Length (ern)
I-+?ig. 3. Length
in the
Bering See
distributic~
of walleye pollack
internatic~al
and Okhotsk Sea
a) males
b)
-=- Cxhctsk Ses
females
-
12
i~
caugh~
waters of the Bering
1991
Age distribution
walleye pollack 1991
400
1
350
85
300
86
Q)250
78
,.
E-2OQ
0
L-
a... 150
100
J
50 ,
0
I
I
•
,
I
I
I
I
I
I
I
1 2 3 4 5 6 7 8 910111213141516171 81 ~
Aga
I0
8erin~.Sea
_
Okhock Sea
•
Fig. 4. Age distribution of walleye pollock caught
in the international waters of the Bering
and Okhotsk Sea in 1991
-
13
(males and females)
Age distribution
a)
walleye pollock 1991 males
,
350
300
86
85
1
250 .;
~200
E
o
0:. 150
•
78
I
I
87
100
50
o.
. 84ß3...~1
88
.
12345678
I
77
73
75
~
... ~ . 7q1
I-
grJ32~
eil9
r,
~~
91011121314151617181~O
Aga
ID
Bering Ses
~ Okhotsk Ses
I
Age distribution
b)
walleye pollock 1991 femaIes
85
IDEering See ~
Fig. 5. Age
distributic~
Okhctsk See
I
of walleye pollack caught
in the international waters of the Bering
and Okhotsk Sea in 1991
a) males
b) females
14
-
•
".
'
.
•
walleye pollack 1991
males &females
55,...------------------------.
50
45
•
..-.40
E
~35
.c
~
"&30
c
0)'
--l
25
20
15
10 .l.-...y----r----r--,--,---r--,---r---r---r---r--,---r---r---r---r-~~~_r__l
1 234 5 6 7 8 91011121314151617181920
Aga
I
0
8.S. v.8art -
•
8.S.
0.8. v.8art -
0.8.
Fig. 6. Growth curves of walleye pollock caught in the international waters of the Bering and Okhotsk Sea in 1991
(males and females)
-
15
..----------
-
walleye pollack 1991
a)
females.
55...--------::-:::=:::;::;:::E:;=~:=T=1
I
+ +
50
45
-.40
E
~35
..c
"&30
c:I)
-J
25
20
15
10 ...L...r--r----r-~.....___.__.__-r-_,_-r---r-..__~r__r___T__,..__..___r_____r_l
123 4 5 6 7891011121314151617181920
Aga
1-
8. S. v.Bert
b)
-
+ 8. S.
O. S. v.Bert
O. S.
0
walleye pollack 1991
males
55,....----------------------..
+
50
o
45
+
o
_40
E
"
~35
..r::
0,30
c:
Cl
-J
25
20
15
10 ...L...r-r"---r-~.....__.___.___,__,_.,..__..__..__,..__,r__r_.,.__..___r___.___..__J
123 4 5 6 7891011121314151617181920
. Aga'
1-
8, S. v,Bert
+
-
B. S.
.
O. S. v.Bert
0
O. S.
Fig. 7. Growth curves of walleye pollack caught
in the international waters of the Bering
and Okhotsk Sea in 1991
a) females
b) males
16
•
Contidence limits tor L-int
walleye pollack 1991
56
~
54
I
~
52
50
r
IBerlng
I·
I
Sec
I
48
46
44
I
CM-otsk
Sea
I
42
males
females
m&f
males
femaJes
m&f
Fig. 8. Confidence limits for L-inf of walleye pol lock caught
in the international waters of the Bering and Okhotsk
Sea in 1991
Confidence limits for K
walleye pollack 1991
0.6
0.55
10000tsk Sec
0.5
I
0.45
I
0.4
I
Berfng Sec
0.35
0.3
0.25
I
~
males
females
Fig. 9. Confidence limits
m&f
fo~
males
femaJes
m&f
K of walleye pollock caught
in the international waters of the Bering and Okhotsk
Sea in 1991
17