This paper not to he citcd without prior reference to the authors.
C.M. 1981/H: 17
INTERNATIONAL COUNCIL FOR
THE EXPLORATION OFTHE SEA
Pclagic Fish Cttce
f
REPORT ON THE INTERNATIONAL YOUNG FISH SURVEY 1981:
HERRING DATA
hy
A. Corten and C.l. Kuiter
Netherlands Institute for Fishery Invcstigations
PO Box 68,1970 AB IJmuidcn
Thc Ncthcrlands.
This paper not to' be cited wi thout prior reference to the authors.
C.M. 1981/H: 17
International Council for the
Pelagic
Fish Cttee.
Exploration of the Sea.
REPORT ON THE INTERNATIONAL YOUNG
FISH SURVEY 1931: HERRING DATA.
by
A. Corten and C.J. Kuiter
Netherlands Institute for
Fishery Investigations
Haringkade 1, Postbox 68
IJmuiden, The Netherlands
•
Introduction.
This paper is one in aseries of annual reports on the International Young
Fish Surveys. These surveys are conducted each year during the monthof
February in the North Sea, Skagerrak and Kattegat. Their objective is to
obtain recruitment estimates for herring and a number of roundfish species.
An evaluation of the survey results up till present is given in the latest
report of the two ICES Working Groups that are dealing with these surveys
(Anon. 1931 a). This report only presents the results from the 1981 survey
as far as herring is concerned; data on roundfish species are presented to
the 1981 Council Meeting in document G : 71.
Methods and Participation.
•
All vessels participating in the 1981 survey were equipped with the standard
GOV bottom trawl far sampling both herring and gadoids of 1 year and older.
In addition, most ships carried an Isaacs-Kidd Midwater Trawl (IKMT) for
sampling O-group herring at night. Details on the survey pethods are given
in the "Manual for the International Young Fish Surveys in the North Sea,
Skagerrak and Kattegat" (Anon. 1981 b).
Participants in the 1981 survey were:
~~~~!~~_____________ ~~~~~~~_
Fed. Rep. of Germany
The Netherlands
'Norway
Sweden
U.K. (England)
U.K. (Scotland)
U.S.S.R.
A. Dohrn
Tridens
M. Sars
Argos
Cirolana
Explorer
Korifena
~~~!~~~____ ~~~~~~!_~~R~~!~~~~~
21/1
2/2
28/1
3/2
28/1
12/2
26/1
-
7/2
5/3
20/2
19/2
14/2
25/2
10/2
G. Wagner
A. Corten
J. Lahn-Johannessen
O. Hag ström
W. Parnell
A. Saville
Yu. Vialov
Unfortunately, France had to cancel its participation in the 1981 survey because of a fire on board RV "Thalassa ". Also Denmark VJaS unable to participate in the survey because its new research vessel "Dana" was not yet available.
- 2 -
Results ..
~:~~~~R_E~~~~~~_~l~~~_~~~~~_~~9_~~~~~_~R~~~~~l~
Five vessels (Cirolana, Tridens, M. Sars, Explorerand Argos) fished for
herring larvae wQth the IKMT. They made a total of 289 hauls in 109 statistical rectangles. The coverage of the North Sea, Kattegat and Skagerrak was
fuirly goOd, except for the northwe,stern North Sea where fishing was hampered by bad weuther •
. The highest densities of herring larvae were found in the southeastern North
Sea and in the Skagerrak and Kattegat (figure 1). For the southeastern North
Sea, this was the second year in succession with high numbers of larvae,
wtlile for the Skagerrak and Kattegat the numbers found in 1981 were very much
higher tmn in any of the previous years:
I
t
Year class
I
~
1976
1977
1978
1979
1980
~
Number of
sq~~~~~_~~~E~~
77
122
101
133
109
Mean No/square
!~~~~_~~~~E_~~~
5.8
3.9
10.5
28.9
21.8
Mean No/square
eastern N. Sea ,)
0.0
1.5
0.9
63.3
32.6
Mean No/squar~
Div. III a.
0.2
0.9
7.9
9.5
35.9
,) east of 5° E.
Larvae sampled in the southeastern North Sea were of a relatively large size.
This was probably due to the fact that by Feeruary a large proportion of them
were distributed already in coastal waters, where food supply is better than
in the open sea. Considering the fact that the number of large herring larvae
in the coastal zone was higher tmn in any of the previous years, the prospects for year class 1980 seen to be rat her promising.
A detailed comparioon between the results of the IKMT-sampling in 1981 and
previous yeurs is given by Corten (1981).
~-R!~~~~_E~~~~~~~_~~~!~l_l~~_~~~~~_~2I2_~~~~~_~R~~~~~l~
•
Sampling of 1-ringed herring wus concentrated in the herring standard area,
which covers 57 statistical rectangles in the central and southern North Sea
(figure 2) •
Mean numbers per haul are shown for euch statistical rectangle in figure 3.
As in previous years, no distinction has been made between autumn and spring
spawners, because this classification is difficult to make in juvenile fish.
It is ussumed that the great majority of 1-ringed herring in North Sea and
SKagerrak were autumn spawners of year class 1979. In the Kattegat, the mujority of the 1-ringed herring were presumably spring spawners of the 1980
year class. Research 1lf Swedisch ~rkers has shownthat I-group herring cuught
during the IYFS in February 1980 consisted for60% of spring spawners of
local origin and for 40% of autumn spawners probably derived from the North
Sea (Anon. 1981 c).
Tbe numbers of'1-ringed herring caught in the central and southern North Sea
were at about the same level as in 1980. Tbe mean density of 1-ringers for
the herring standard area was 551/hour, which is 38% of an average year class
from the period 1968-73 (Table r).
Tbe distribution of the herring was also similar to the one in the previous
year. The main concentratians were fa und in the German Bight, alang the Dutch
coast and in the Kattegat. As mentioned earlier, the Kattegat herring were
probably partly spring spawners.
,
I
'
~
I
- 3 -
~
Compared with 1.980, the herring in the German Bight were distributed slightly
more to the west in 1981. This may be due to the greater length of the fish
in 1981 (the 1-ringers in 1980 were exceptionally small). Mean lengths of 1ringed herring are shown in figure 4.
I
Tbe fact that yeär class 1979 now appears to be of the same strength as year
class 1978 is remarkable in view of the great difference in abundance'at the
O-group stage. Year class 1979 was much more abundant at this age than year
class 1978 (Corten, 1980), and yet the abundance one year later is approximately the same. Apparently, a distribution of O-group herring such as found in
February 1980 is no guarant.ee for a good year class.
One possible explanation is that the distribution pattern of the larvae in
February 1980 was not quite optimal yet. A comparison with the IKMT-results
in February 1981 shows that in the latter year the larvae were distributed .
even further inshore, and they also had a greater iength than the larvae in
1980.
e,'
Alternatively, all the conditions for a good year class 1979 may have existed
in February 1.980, but the year class may have been decimated in the following
months by some unusual predator.
~:~~~~~~_~~~~~~~_~~~~~~_~~~_~!~~~_~2I~_~~~~_~~~~~~2~
Mean catches per rectangle of 2-r!nged herring are shown in figure 5. Substantial numbers of this age group were only encountered along the Dutch' coast and
. in the Kattegat. A large proportion of the fish in Kattegat consisted probably
~f local spring spawners of year class 1979. The 2-ringers along the Dutch
coasthada rather low mean length, and a high percentage of very small or
opaque otolith nucleii. Both characteristics suggest that these fish will recruit to the spawning stock of the Southern Bight and Eastern Channel.
'References.
•
Anon., 1981 a
Report of the joint meeting of the International Young
Herring Survey Working Group and the International
Gadoid Survey Working Group.
ICES C.M. 1.981/H : 10.
Anon ., 1981 b
Manual for the InternationalYoung Fish Surveys in the
North Sea, Skagerrak and Kattegat.
ICES C.M. 1981/H : 9.
Anon., 198 1 c
Report' of the Working Group on Division 111 a stocks.
ICES C.M. 1981/G : 12.
Observations on herring larvae caught by Isaacs-Kidd
Trawl during the International Young Fish
Survey in the North Sea, Skagerrak and Kattegat in 19771981ICES C.M. 1.981/H : 19.
Corten, A., 1.981
and G.Van der Kamp
~fidwater
Corten, A., 1980
and C.J. Kuiter
Report of the ICES Young Fish Survey 1980: Herring Data.
ICES C.M. 1980/H : 35.
/'
- 4 TABLE I - Mean abundance of 1-ringed herring for the herring standard area.
Survey year
NO/hour
1970
1968
822
1971
1969
2647
1972
1970
1629
1973
1971
827
1974
1972
1195
1975
1973
1529
1976
1974
452
1977
1975
1976
342
575
1978
•
Year class
(assuming all fish are autumn spawners)
1979
1980
1977
139
1978
535
1981
1979
551
E5
E6
E7
E8
E9
FO
F2
F1
F3
F4
F5
F6
F7
F8
F9
G1
GO
G2
52
51
50
I
- t_ _
600
-j-_-t_~__J/rr_t:'7--+_-_+--t_:2---- Q-r-:_~-'~---i~~~}-~oI,i
~~
1
---+--t----+---+--I----t----+------t----t---+-f
--i----L.~~~
~-~~
cr
Q;ft\\C
Q
4-_
tj"
H
2- Q'":
~
2- .lQ.
29.6
.2.
~
31.1
/
2
47
2-
-
..<--+---+---+---+-_+-_-+-__;.'
"'"" 2- l2. 2
29.7
~ 1~"(
1-
25.1
2- 2. 4- .!±.
,26.3
27.5
58
Q
1-_
1
o
48
1
'i\I~
1-_
JJJV
Q
1-_
Q
57
49
Q_+-1_-_-
I
2- 1
26.4
~
2- Q
-
9- TI 2- 22
31.4
38.7
1- 35
30.9
..
46
\
45
i--_-+-_-I-_-=:...;rL.tf::::>;....q....... _ _+-_-+__+-_J}
40
28.9
1-
~8.1 '1
)
1- 69
2- ~
24.6
27.8
44
43
2-.lQ. 2- 30 2- 11 2- 28 1-.ll 2- 1
26.8
24.4
30.1
29.6
28.3
27.9
~- 20 2- §l 2- 2Q 2- .2.
30.1' 25.7
3.2
30.0
"'\ 4- 23 5- JJ.
27.9
1-
.s
24.0
27.6
2-
!±.
40
!±.
39
?(;,
?< ~
\ 2- 6
},.'-E6.4
230.0
228.5
2-2.2.
2-
2A h
\
.s
?~
<
.s
2-
.s
31.3
2- Q
25.8
26.0
\ 2- 20
228.7
~25~
)
41
28.4
2- .1 2-
4-.l2.. 2- 23
42
.s
.!i
38
37,
2- .1 5- 1.2. 3- 60
27.8
34.3
34.2
2- ~ 2- 24
25.9
29.5
4- .!i 3- 21
34.6
33.9
:::.:.)~:,,__
--
~
26
3-.!Ql
u.
36
0
'u
35
34
IKMT-sampling February 1981
Herring larvae year class 1980
33
first figure top row: number of hauls
second (underlined) figure top row:
mean number of larvae per haul
32
31
bottom figure: mean length in mm
30
29
Figure 1
28
ii
27
o
10
o
12
---
•
_.........
•
--
....
-.U--
................
~
ce.
.
_~
----...----~
aWJe
tJ
-_.-..
---..----~-----------..----------
•
r'
F I
i~
f4 J i":" l..; f'~:
E !l E 6 E 7 E 8 E g ~- r - - - - I - - - - f - - - - i - - - " c - - - - - , - - - - - ' - - - - --_.. ~~-.-,----. ---- -- - . - - l
6/
~
-+----+---:
" ' + - - - - 1 - -..
""
I_ _j
y
J
~J,-.---!----l!_._--L--~t?r:~
r
~IL_.-~;' --; -.,,- ;;~~
'"
~
"- -
I
,
;·~----~r---'-·
3
~7
"
".
:2
.
\ /.
---I'----. ~~
50"+-----I---/----t---1.,/'-t---+---1·---1---+----I---+----I---il---I----I---II---I __ ~
~-l---:2-l
~-+_--I----I--_1I,
1---;
:l
~1
_
~~
~--;-I·--:2---:21~~-· '--;l--'-~----;I:2
"=L-i~
-,.1 .
..
,"
S
~~
~J
1:1 I
u.:
....--~-.-~.-~.--.- .." --:
.~ --.~----.~-~'---
.I".
IYFS February 1981
.'
Squares marked- by diagonal lines are
part of the herring standard area
.1..
..
./
-','-,
//>--'-----;,
.,\///1
J L~:~I'
~....
--~
----r-·-'1-
I '-i::1
l'I
-~L_
I
:2
-
..
L-12l
~n
L1e;
T
T LJ::
I
~1_~'7-~)~f' ~\ I'~
-1/'-
•.
-:'\.,~r
LI~J
LI3
I'
.l-J2
Lil
,.J-i;-'I-/""--I·.
I . . . . . . '\-"1-
w,'.Gi
"/_L--..;.
"J ' - W
-.\
... ~
4
•
v J
/~il-'--I --.-<~
1:"[" I
C-J
r...
+- ~::j
~--1' .----~- ._--, --r~
I
d
Numbers of haula made by bottom trawl
(5.J'cS.
-',._I-r
~
j-
Figure 2
' L - '
-<-~/.,
J
. rEiF 7
-------...-------------~ _.~- --..--------------
,,~
...
j
, / / . " ~I
-
'
-r
r
tI
....
J9
JO
:17
--
·'1'- _:1=
...
"1'
.,_I.
":-l-
-J.:..l,
=,J
J 32
----l---J.
- - - i - - - - l - - - i..--.i-.---.-..
7-
1u-
\ j'
JI
- E
~
E 6
E 7
51 IJ
E B
,
I!l
I!l
r
f:J
•
r
{;
I
~-
I!l
I!ll
------\-
~
•
r'-
-
___L_.
I!l
I!l
I!l
I
I!ll
I!l
-- t--
/
1-
"I
I!l
~40
" c..
§~
I-
l~
I!l
~~u
bf1 1
s:a
E::J
Y
I!l
I!l
2
I
I!l
I!l
2
I!l
-
19121'.2
A
-
;-;
.-
Q.
"-
/
I ff2Y
'16I!l
3Y7S
IY9
I!l
I!l
-- -
-
2
I!l
A.
~
;t
-_I
SY
31
86
36
~6S
2
Y
\
:2Y7:2
I
~
~- SStlr
SS6
l ='rl
•
6~[
_ .
~7sl
-63-2
. r...·6--:.:-.-=:---.
"
•
1
)
.....
I
r-jI
J
1- _
!
i
. -r'--i··
..../
I
..11---__-_1.I
-::::'_-.1..-
J [.
-I~-+-I----11_LII
_ JI
I·
.'0
.:1-
...J.:
Ei'
I L-
I l'
1
I~ ..
E 5
'j
I
[ 7
E -H
-i
~
~.~~
0.~E:I
I
-
J7
<J DI>
71
-
·0
~:~r:..
~
o
:2
•
.1"--
0.~~
/0
0.00
4--
!iS~
13.58
~.8~
T
-r
I
·I
I.J
,
V
IIG0
-oe::::
_tJS,77
...... I Y
--- -....,
:-.. 1.' ~
~.!1l!1l
!
i2.I11i!2
--:2
111
~.i211
i2.(j11l
i2.I1IIII
5
I
18.!i0
i2,!i8
Li
fI
---
11I.0I1I
111.11111
Y
<-..r:
L\.
--_...
,.
~-_
_,'./
...-...:,.,--
19.00
0.011l
7
I
18.17
1.59
8
33
/8.13
~
E
a
l!1
16.71
1.93
IY
2Y
15. 12
2.27
221
75Y
16.67
IY
YYI1I
IY. B I
I. 78
5
9
1.~9
16.IY
1.68
23
32Y
6
3~8
35Y
I
115Y
15.~11I
5
I:2S
- I~. 79
1.8Y
12
Y2
I. 15
11I.11I11l
,--
17.~2
I. YI1I
1111
1i227
16.79
I . YI1I
\........
~
,.-
--
~
S:2·L
--"
3
~l!7
15.12.
_~/~7
6
8
17.58
I. 3Y
----_.. _-------_.
893
15.87
_ _ _• _ _ 4"
-_
I. Y7
-
1.~3
..
I.9~ - )9S:
I !\..-!i9~
1~.78
17.2~
-'
(.:-;--.,;:-
i ~'
-'
t
rt
1.8Y
r;r
-4
I
~
~- ~-
,98111
821
.,
I
' 5257
15.92
I
TI
2.72
_
-:L...__ ~I
..' /~--_._-,J
. '
-----j------i--------·I----r-----'-···----I'--- .- - --,------. -- - - , - - - - - - ! - - - - - I - - -
.- I •
f-.
1~.13
9
IR!
-- ; .-/
Y
JB.~~
11~1
l~-j _ _I~~~,/
....1
S
1.11I~
111
1~.88
·t
,-.-
!1l I
111.i2111
:2
-1-- -..
I
2
3
~
~
-
'
I
ß
i
-_ ..I
,
•
F
~.~ß
0.~11
·(jQl
~" .i2111
I
50 •
"
I
J
.-t-
•
•
l g
T
NUl18ER OF' HAULS
I
N/HOUR
.!.
MEAN LENGTH
STANDARD OEVIATION
,---.r--------.+--------i- - - .• ',--
I L-
I
I
I '
I
1".I.
I
. - .. !.
""
~~
I
I
I
.:1.1
~L~
..1 I
E
~
8
~
~9 •
4
C7
r"~.o...
~0
'-
!lB •
. 1-.
'37
/
~I~~
12
28
PI
I
S
fI
92
-Lj'
I I:
•
!
"i'
I
I
I
I
.,i-
.:I
. _ ..4
~,
._J
'li,
I
f
1I J
I~
i'
I
-,.
,-
I
;.~-.
'l . "
5:fl'--
'1I-
..
\-.
~
I
I
.: ...
I.J
., I
I.
_lU
1,- LI •
..
I
I
,"
_,
•
T
I
:~,i
I
-r
-ff~--I---I--' '--1"
_Lp
-],
I
I·
I
Nm1BER Dr HAULS
N/HDUR
HEAN LENGTH
STANDARD
DEVIATIDN
I
f - ._.._....- . -_.. - -
.,
i'
~,'
...
9
I b'
I'
.-
1:2( .
_.1
.. '
I
'1-
..,.i
l
-j.::
I
l.,
i
-,
,'J
I