ICES 1992
PAPER
C.M. 19921G:70
Ref. J
FOOO ANO FEEOING OF COO IN THE SKAGERRAK ANO THE KATIEGAT
IN 1991
by
J. Oorman, Barbara Johnsson and P.-0. Larsson
Institute of Marine Research
P.O. Box 4, S-453 00 Lysekil, Sweden
•
ABSTRACT
Within the international stomach sampling programme in the North
Sea in 1991 Sweden made three surveys in the eastern North Sea,
the Skagerrak and the Kattegat. Sampling of stomachs were made
in all three areas although the latter two areas were not included
in the international programme.
A number of species were sampled, butcod stomachs were first
analysed, cod being the most important and interesting species
with seperate stocks in the Baltic, the Kattegat and the Skagerrak.
In this report results from the first quarter is presented.
The stomachs were analysed according to the procedures agreed in
the international stomach sampling programme. The results are
compared with results from the North Sea, the Baltic and previous
investigatioos in the Skagerrak. and the Kattegat.
INTRODUCTION
To extend the basis for multispecies assessment from what had
been obtained largely in the stomach-sampling programme
undertaken in the North Sea in 1981 (Daan, 1989) the Multi-species
Assessment Working Group in 1988 recommended that another fullscale stomach sampling exercise should· be executed in the North
Sea in 1991. The recommend~ltion was endorsed by',lCES and tl1e
sampling successtully realized (Anon., ·1992a). .
I
•
The project greatly benefitted fram the ICES Quarterly
International Bottom Trawl Survey, which commenced in 1991
(Anon., 1992b). In tl1cit Sweden participated in the first three
quarters and consequently also 'sampled stomachs from a number of
fish species. The Swedish sürveys covered the Kattegat, the
Skagerrak and part of the eastern North Sea. Stomachs from the
North Sea were partly exchanged according to the ,programme~ but
all stomachs fram the Kattegat and the Skagerrak and seime from
the North Sea were analysed in Lysekil, Sweden;
The results from the Kattegat and the Skagerrak will not be
included in the North Sea data base and therefore the basic results
and same processed data from the first quarter of '1991 will be
presented here, compared to' other data.
MATERIAL AND METHODS
The stomach sampling was performed during the International
Young Fish Survey in February 1991. The trawl used was a GOV -86
with a sprai extension and cod end ( bar length 11 mm). The catch
was measured and weighed and sampies taken out for stomach
analysis in accordance with recommendations trom the ICES North
Sea stomach sampling project 1991 (Anon., 1990); Everted
stomachs were discarded but not replaced and regurgitated
stomachs were noted. To preserve the stomachs individually we
used tube gauze, which was tied between each stomach and
sampies from one haul thereby kept in one strip. The tube gauze
strip containing the sampies were put in 10. liter' buckets with
buffered 4% formalin. Later the ~homachs were' transferred to' 96%
denatured alcohol.
In total 336 cod were sampled in the Skagerrak, 653 in the .
Kattegat and 166 in The North Sea. Of those 87,5, 89,7 and 91 %
respectively had stornach content.
The storriach content has, whenever possible, been identified to
species level except for particularily difficult groups as
gammarideans and ostracods. Often broader categories (family,
order, class) had to be used dependingon the state of digestion of
the prey. For instance, bristleworms weie usually categorized as
Polychaeta since they often .were found in a late. dIgestion state
and we're very difficult to identify even, t6 .an order..
RESULTS
All food items found are listed in Table 1, 2 and 3 with weights
and numbers, separated on cod siie classes. In figure 1 a - c the
percentage distribution (by weight) of prey groups are shown by
cod size class. To get a reasonable number of cod in as many size
classes as possible, 'cod <150 mrri and >700 mm are joined to ane
.'
size class respectively.
•
In figure 4 the mean weight of stomach content per cod size class
is shown.
The main prey groups' (by weight) are crustacea'ns, bristleworms,
and fish in approximately the same proportions, in the three areas,
although the proportion of fish in the Skagerrak cod is slightly
smaller and fish is there dominating only in the largest size class
(Figure 1b).
There is a wide range of crustaceans represented (Figure 3 a - c). A '
significant difference between the areas is that in the Kattegat
euphasians (krill) dominate (63% of the cnjstaceans, Figure 3c),
where as in the Skagerrak and t~e North Sea crabs, mainly
Portunidae,' show a similar dominance. Of the cammercial
crustaceans, La. pandaiids and Nephrops sp., the 'share is 7,34 %
of total weight in the Skagerrak and 2,2 % in the Kattegatt. In
Figur~ 3b the category "other" .contains mostly Pasiphea sp.
In all three areas cod with a length <250 mm feed to more than 90%,
on invertebrates. Large cod (size classes over 500,mm) fead .
approximately to 30-75% on fish. Figures 2 a - c show the
distribution' (in percentage of weight) of thä different groups of
fish found in the stomaehs related to size class in the North Sea,
the Skagerrak and the Kattegat respectively. In the Kattegat large
cod primarily had eaten herring, whiting and flatfish, where as cod
e
,
'
caught in the Skagerrak and the North Sea had fed on gadoids, and
,again mostly whiting. lri the Skagerrak 52% of tne fish consumed
consisted of commercially important species such as whiting and
haddock. In the Kattegatt 43 % was .commercial fish arid approx. 50
% of that was herring, where as whitirig and haddock were the
predominant commercial species in the North Sea. Cannibalism did
not seem to be frequent (' in the catego'ry "gadoids", (Table 1) cod
. can be hidd~ri hut this category is small 'comparE3d: to 'thä others}.
,
'
Significant amounts of molluscs had only been eaten in the
Kattegat. Cod with a size of 20 - 40 cm had consumed. rather high
numbers of bivalves.
DISCUSSION
•
The material from the North Sea is smalI, but the 'main features of
the food composition corresponds weil with what ls reported .by
e.g. Daan (1973, 1983). arie exception is cannibalism, that was
small in all three areas. As Daan (1973) points out 'cannibalism
decreases with small yearclasses arid the 1990 yearclass was
small or average in all areas (Anon., 1992c).
.
Between the North Sea and the Skagerrak' resuits the differences
were rather smalI, less fish and more crustaceans in the Skagerrak
material. lri the Kattegat, however, there are striking differences,
not so much in the total proportions of the, main groups, but in the
fact that krill seeni to be extremely important at least this time
of the year. Also the high occurence of herring in the stomachs is
significant. This indicates that cod in the Kattegat should feed
more pelagical than in other areas, which might seerri logical in
this very shallow area (average <20m). However, in February 1981
cod had eaten insignificant amounts of krill in the same area, (only
about 2% of total weight of crustaceans compared to our 63%), as
presented by Börje et al. (1987).
f
Nephrops norvegicus is the most important target specias of the
trawl fishery in the Kattegat and a' large of ·the Skagerrak. Much of
, the stornach saniplirig in the Kattegat and ,the Skagerrak was made
on the Nephrops grounds, but the arriount eaten by cod was rather
small~ 20/0 in the Kattegat and 3.Sro· in t~e Skagerrak, conipared to
16 - 60% according to several reports from the Irish Sea; rEwiewed
by Armstrong et al. (1991). Even considering the probable
differences in 'cod' size distribution (sampling trom landings in the
Irish Sea) the difference is large.
REFER8'.CES
Anon., 1992a. Progress report on the ICES 1991 North Sea stomach
sampling project. ICES, Doc. C.M. 1992/G:12
Anon., 1992b. Report of the International Bottom Trawl Survey
Working Group, Copenhagen, 13-17 January 1992. ICES, Doc.
C.M. 19921H:3
Anon., 1992c. Report of the Study Group on Demersal Stocks in
Division lila. Copenhagen, 10 - 17 February 1992.
Armstrang, M.J., Smyth, D. and McCurdy, W., 1991. How much
Nephrops is eaten by cod in the western lrish Sea? ICES, Doc.
C.M. 1991/G:15
Börje, M., Fogelgren, J-E., Tengelin, B. and Ulmestrand, M., 1987.
Födoval av torsk (Gadus morhua L.) i Skagerrak ach Kattegatt
under februari 1981. Meddelande frän Havsfiskelaboratoriet,
Nr 320. 13 pp.
Daan, N., 1983. Analysis of the cod sampies collected during the
1981 stomach sampling project. ICES, Doc. C.M. 1983/G:61
Daan, N. (ed.), 1989. Data base report of the stomach sampling
project 1981. ICES Coop. Res. Rep., 164, 144pp.
TABLES:
Table 1 : Primary data showing fooditems (weight and number)
found in cod from the North Sea.
Table 2: Primary data showing fooditems (weight and number)
found in cod fram the Skagerrak.
Table 3: Primary data showing fooditems (weight and number)
found in cod tram the Kattegat.
•
e·
Norlh Se.
TOlalllamples
No ""nh load
No emply
No l"!Jura.
Slzeda&S
Food n"ml
11
10
1
22
-
-!! f 3
100
120
welgh
00· !-velgh
00
41
37
3
1
150
1.85
6
0,18
~ I· 1,7
0,1
1
15
15
0
200
welgh
II'NEATHJlATES
Polycha.te
Aphlodlle
14
14
0
welgh
00
~
2,6
250
no
welgh
3
0,1
0,1
0,15
0,4
01
8
0,2
0
2 0,05
21
3
0,1
1
0
1
1 0,05
0,35
33 0,28
0
1
0,2
~1 ~
0,05
0,6
1
1
8,3
1,6
3
1,1
0,2
2
3 048
0,5 0,6
1
0,1
1
0,4
1
2,1
0.2
0.1
1
1
2
0
0,4
5
0
5
5
0
-
400
2
1
\,velgh
00
0
8,3
2
3
15,6
1
~elgh
00
700
\,velgh
00
2
1
1.8
4,6
2
1
1
1
1
0
600
500
welgh
'00
3
3
0
-
3
1
3
1
_
_
0
0_
1100
800
00
welgh
00
""elgh
59,1
166
151
--
1000
welQhl
no
5
0,8
1
2
0,2
5
0
6
7
3
9
10
0,4
2
0,7
0,1
1,4
4
1
4
10
3
0
1
1
6
1
1
0
3
4
0.6
0,7
2
4
0,3
0,5
3
5
0.5
2
0
1
1~ ~
1 0,15
1.7
0.5
0.9
0,2
2,5
0,6
1,7
0,3
5
1
29
2
1,4 .
2
0
2
1
4
1
5
4
2
2
0.2
1
3
1
2
0
1
0
1
föIj;Q
0,558
---33
0,000
0,934
O,OO§
0,670
12
0
r-!
c-!2
0,030
1b
0
-E,OI?
0,0 0,002
1
0,3 0.018
6
0,1 O,OO~
3
0,0 0.000 ---0
11
1.7 0,102
0,5 O,O~2
3
0,0 0,000
0
1,0 0,062
64
0,0 0.000
1
0,9 O,Q~~
'~
3,4 O,2Q!
13
2,1 0,126
7
14,7 0,880
22
1,9 0,114
16
8
~~ ~!~~
44
4,9 ~~~!
0,5 0,030
1
0,0 0,000
2
5,7 0,341
3&
0,3 O,O!~
2
0,1 O,QQ§
1
0,0 0,000
0
0,0 0,000
0
21,1 1,263
17
_ _5,? -E,~~!
1
4
~,~ ~E~
0,5 0,030
1
0,2 0.012
1
1,5 0,087
23
0,3 O,OI~
1
9,9 O,5~? _ _1_1
6,7 0,401
3
16,4 0,982
12
127,2 7,614
1
28
0,4 0.024
1
__
0,1
1
0,7
0,5
1
2
5,6
-- r - -
0,2
3,6
4
2,3
3
1
1
1
1,6
1
2
0.7
0,3
4
1
1
3
1
1
18
2
2,2
7,1
1
1
1
1.3
2
1
1.2
2
0,6
1
1
1
0.4
5,7
1
1
0,1
1
4,6
5,3
29,4
1
1
7
12
3
-- -
-
5
0,6
1,3
Tal ""elg ".. welgt
0,5
-1,9
0,5
0,2
0,5
--- - -
2
r-----; ~
73,1 4;'37;
1
0,1
0
1,7
0,2
1,3
~
'~
00
1
11,2
__
0.0
15,6
0.1
11,2
1
I-
0
00 f,yelgh
13
12
1
O,~
I-
1
350
welgh
11
9
2_
--
-
6 1,28
~
1
1
24
21
2
1
300
0,2
,",olluace
ßucdnldae
ßucclnum
AJlolheulhll 10 Cruatacil
Cumacil
Olaslylldae
Mrald.
SChlslomysls ornata
leopoda
Aslacllla lonalcOlnls
Clrolana bocealls
Amphipode
Gdlll marldea
Caprlllildae
Oecapoda
C8Iidea·
PandaiKlae
Pandalus montagul •
Pandallna brevlostrls·
PrDCessasp
Ctangonldae
Ctangon So
Crangon crangon '
Ctangon allmanl
PontoDhllus soln05US
Eulus puslolul Rept.nUa
Anomura
PaolXldae
Pagurus sp
Pagulus bernhardus .
PaQurus p~deuxl
AnaD80ulUs hyndmanl··
Galalhes 50
Munldasp
Brachvura
POl1unldae
llocardnus so .
L10carclnus holsalus
llocarcinus arcualUS
1
00
lable 1
1
-- -- --
3,4
1
3,7
0,4
1 34,9
1
12
~
1
-- -
45,2
6
6,9
labia 1
Norlh S..
Tolal sampies
No wlth lood
No amolV
No ragurg.
Sizadass
Feod hams
Eballa sp·
Hyas coarClalul
lhhod/ll mala
11
10
1
100
~elgh
22
19
41
37
3
3,1
120
150
no welgh .. no
~elgh
15
15
0
14
14
0
200
no r,v/llgh
0,3
1,2
24
21
2
1
300
250
no
w/ligh
walgh
no
2
1
0,3
5
11
9
2
no
350
400
welgh
no Iwelgh
1
0,4
5 12,6
5
13
12
1
1
8
2
5f0
500
welgh
no
3
3
0
600
welgh
no
2
1
1
1
1
0
no
3
3
0
700
800
liDO
w/ligh
no r,velgh
no "'elgh
0,1
2
0,1
1
9,3
1 11,7
Gadldae
Gadus mOlhua
Merianglul me~angul
MelanoQrammul aoolalinul
Tnsool erUI /lsmarckll
TrlsOpl/lrUS minulul
2
Ammodylld..
IlyparoplulSP
0,2
Call1onymldee·
Callionvmus 50
Gobld..
Gooy
1
1,8
0,5
4
1
2
4
0,53
3
~yngnalhld ..
1
0,5
2
1
0,2
0,4
3
6,9
1
1
Zoercldae
loare/ls vl~lparus
2
3
0,7
3,5
1
1
13,5
6
0,2
1
46,9
40,6
14,4
2 106
1,2
1
2,2
1
6,8
12,6
1
2
4,5
2
1
3
45,1
1
112
4,1
1
4
f-
--
22,4
1
346
46,6
4
1
42
22
0,7
1
2,3
2,4
58
70 22,7
2
60 19 1
1,8
49 81,5
0,2
0,012
3
0.000
7,063
0
7
0,0
118,0
--- ._-
-- ._- ._- f --
-- - - -
2
36 86,4
2
27 98,5
16
156
25 45,1
•
1
9,8
1
144
3
0,000
0,209
10
29
c----a
11
0
6
__1
- -0
2
0
0,0 -.Q.,Q.QQ
---_ _1
2,2 O,13?
0,006
4
1,341
1
_ _1
~ 2,34Q
05 O,03Q _ _1
0,1
22,4
1
1
1
67 61,6
0,0 0,000
1,6 0,098
_ _O!~ ~!!~~
0,0
3,5
1
39,1
1,4
124 15,8
4
15
1
8,2 ~
53,1 3,178
-- - --
22,4
PiSC/lii
0,060
1,245
16,24
5,0 .-E,~~ _ _2
2
21,3 . 1,27~
15
537,6 32,178
165,2 9,888
~'
12,6 0,754
~3
5,0 O,29~
4
0,5
1,0
20,8
271,3
0,0 ~~~
16,0 O,9~~
EllQS
TOlal
2
1
8
- ---
0,1
27,7
1
Pholldldae
Pholls lIunnellul
Pleuronectllorm••
Pleuronecl/dee
Umanda IImanda
ltippogrossoldes 5p
1
1
1
5
no
1
Fl9l
Clupeldee
Clupea harengus
-----
TOI w/lig 0;. walel Tol no
1000
W/lighl
no
1
271
Ophlurolda
166
151
13
2
1
1
0
863
42
69,2
~
4
9,6
5,2
1670,7
0,575
0,311
1
5
524
labia 2
Sklg.rrlk,
Total sampleaNo Wilh lood
No IImptySizeclass.
food lIems-
11
8
3
100 ;
welgh
j
39
27
12
120 Ino
weigh
54
48 I'
6
200 '
91
78
13
150
no
weigh
10
9
1
250
weigh ' no
no
12
12
0
300
weigh ' no
13
12
1
350
\
weigh :no
weigh
24
24
0
500
43
41
2
400
f,veigh , no
weigh I' no
no
8
8
0
700
25
21
4
600
weigh
welgh
no
5
5
0
800
weigh ; no
no
336
294
42
1
1
0
900
weigh
Tot wei °/. weig Tot no
no
tMRTEmATES
Polychuta'
Aphrodile
Polynoidae
0,3
0,4
1
1
Molluscs
Bivalvia
Maci/idae
Gasllopoda
Buccinum
Tu/rllalla
8,4
0,4
0,2
0,3
0.3
16 11,7
1
1
34 16,6
8,6
2,3
13,6
0,2
1,5
10
2 0,55
1
1
2,2
3
2
1
4 ' 3,6
2
1
18
4
1
0,3
1
0,6
11,5
1,8
1
1
4 31,8
1
6
25
7
4,7
44,8
3
7
2,2
1
0
1
178
1
9,1
1
2
3,7
1
0,1
1
0,1
1
0,7
1
Prlapullda
P/ipulus
Crustacea
0,1
1
Cumacea
DiaSlyhdae
0,03
1
E,ylhrops elegans
Isopoda
Cimtana barsaUs
Amphipode;
GaflVTlaridlla,
0,04
6
Euphaslldae
Meganycuphanes narveglca
Decapoda
0,02
Cariwa
1
Pasipheasp
Pasiphea sivado
Pasiphea mullidenlata •.
Pa"""liJae •
I
Pandalus sp "
I
Pandalus monlagul '
Pandalus borealis I
Pandahna brevlosUis
P,oces&a sp
0,1
P,ocessa nouvllU
1
C,angonidae •
0,3
15
Craogon sp
Crangon cranQon
C,al\Qon aflmanl '
Ponlopholus sp"
Eulus puslolus
Splronlocarls splnus
Aaplantla,
I
18
6,2
0,45
11
4,9
8
0,05
1
1,4
0
0,1
8
1 ,
1
0,1
1
0.2
1
2,2
10,4
3
1
0
7
45,75 1,008
303,1 6,678
2,9 0,064
78
48
3
0,458
0,072
0,200
0,022
0,086
0,015
17
6
7
2
3
1
6.2 0,137
1
19.85 0,437
34
1
1
1
0
1
0
22
I
12
5
21
90
1
203
16
18
52
29
13
3
3
27
1
1
6
2
2
1
20,8
3,25
9,1
1
3,9
0,7
0,025 0,001
0,05 0,001
0,2
1
0,1
2
0,2 0,004
:
0,1
2
0,3
1
0,8
I
0,4
0,1
0,3
4 0,35
0,4
0,3
5,6
0,2
2
1
7
1
2,1
0,5
1,3
1 10,7
5,2
0,6
3
2
2
8
5
4
1
0,1
0,5
0,1
1
9
0,3
0,05
1
1
8
0,3
1,5
1,3
2,5
3,3
3,1
1,3
25
4,5
0,9
0,2
5
1
1
4
8
1
19
3
4
3
0,1
1
2,3
3
0,2
2
2
0.9
0,3
1,2
' 1,1
6,8
3,6
7
1
0,1
1
9,4
8,5
0,2
7
2
1
1,2
1,1
34,8
0,8
4,1
1 30,3
1 26,7
0,4
1
1
1
2
27
1
3
12
13
2
0,6
2
15,5
7
123
1
4,4
3.3
5,3
0,2
126
1
5
2
2
1
0,6
1
0,4
0,4
7,2
2,9
1
1
3
2
47
1,2
32
3
0,5
0,8
87,1
3
80
0,8
1
5,9
10
6,1
12,5
1
2
1.1
1
2,1
1
2,5
1
0,4
1
-
1
0,8
0,8
1
1
0,5
3
1
0,7
0.89
0,4
3,4
7,8
1 12,715
104,9
2,5
217,3
7,7
17,9
90
64,9
2,4
0.2
0,3
3.6
0,1
2,5
3,9
0,45
0,2
0,8
0,020
0,009
0,075
0,172
0,280
2,311
0.055
4,788
0,170
0,394
1.983
1,430
0,053
0,004
0,007
0,079
0,002
0,055
0,086
0.010
0,004
0,018
0
-----------------------------------------------------------------------------------------......,
Table 2
Sk.g.rr.k
TOlalsample.
11
39
No Wllh lood
8
27
No emplV
3
12
Sizeclass,
100
120
Food lIams
walgh - no f,Neigh
N.phrop'a•• · ,
Nephrops norvaalca •
Anomura "
I
Paguridae
0,5
I
Pagurus bernhardus
0,4
Caloearis sp _
Galalheid
Galalhaa sp
Braehvura
0,35
Portunidae
lIoeareinu. sp
lIoeareinus hol&aluS
lIoearcinu. depuralor
Uvas coarclatus I
0,8
Corystes casslvalenum
Ophlurolda
Ophiura sp"
0,02
54
48
6
200
91
78
13
150
walgh
no
1
3
0,3 1.7
2,5
0
6
2,2
0,1
0,2
1
0,9
0,1
9
0,1
0,2
1
Unld. malarlal
PlanllTlalerlal and algae '
0,1
10
9
1
250
no ~aigh - no
1.9
1
6 15,5
3
3
0,2
2,6
14
1
5
1,3
2
3
2
1
1
0,5
0,2
waigh
3
12
0,1
9,9
1.2
no
weiClh
1
1
1
1
5
2
1,9
1,6
13
12
1
350
12
12
0
300
2
2
5
1
waioh
no
3,7
4,2
1
3
3,6
3,6
4
2
1,3
1,2
43
41
2
400
weigh
no
24
. 24
0
500
waigh
no
weigh
no
weigh
no
5
5
0
800
weigh
no
11,1
1
6,4
3
11,2
1
70
6
59,4
5
0.7
1
0,6
17,9
1
1
5
1
11.9
2
12,3
98,1
3
17
3,3
2
12 24,4
4
3 11,8
36 162
12 32,1
1
7
20,6
7 22,3
4
5 23,1
36 234
6 90,7
7
37 23,9
13 47,1
0,4
1
2
4,2
1 20,3
4.5
1,1
1
1
2
2
8
3
1
29,4
11.3
10.2
129
32,4
1
0,4
2
1,6
5,2
0,05
8
8
0
700
25
21
4
600
weigh
no
13,2
38,5
3
0,2
2
2
4
101
7.5
336 I"
294
42
1
1
0
900
13
1
Tot wei "I. weig Tot no
no
158,1
3,483
20,1
162,9
4,7
0
0,6
106,45
30,2
2
49,5
675,4
216,8
.- 3
38,5
0,443
3,589
0,104
0,000
0,013
2,345
0,665
1,091
14,881
4,777
0,066
0,848
0
16
0
12
51
5
3
2
60
11
22
139
44
13
3
2,22 0,049
2,2 0,048
10
9
5,2 0,115
0,85 0,019
0
0
179,3 3,950
2
1
5
0,7
FISt
Clup,ldaa
Clupea harengus
Gadldaa
Merlanaius merlangus "
Melanogrammus aeglafinus
Trlsoplerus esmarekil
Trlsoplerus minutus
Enchelyopull clmbria"
2,2
Call1onymldaa
CalJionymus IIp
11,9
Goblda.
Goby
0,2
aast,rost.lau
Gasleroslerus
2
1
I
38,5
3 127
1 104
4
1
2 59,4
1
2
2
2
2
17,6
16,7
1 60,6
3
3
16,1
2
24,2
3
43,7
3
53,1
2
9,2
1
70,5
66,1
34,6
6,1
40,5
2,7
2
0,2
1
57,5
1
0,5
Stlchaelda.
lumpenus lamprallformes
1
32,1
1
3
56,8
1
3,2
1
16,2
1
I
.':
73,9
123
1
370
7
1
57,4
696.5
219,6
118,6
6,1
162,2
1.265
15,345
4,838
2,613
0,134
3,574
5
19
4
12
1
6
4
148,2 3,265
13
0,2 0,004
1
0.5 0,011
1
19,4 0,427
2
19,2
49,4
1
1
Table 2
Sk.g.rrak
Total Hmpllla
No wilh food
No empty
Sizeclau
Food Ilema
lOlreld. .
lyeodea ap
Lyeodea vahll
11
8
3
100
~elgh
39
27
12
120
00 welgh
91
78
13
150
00 welgh
54
48
6
200
no
~eigh
00
10
9
1
250
weigh
12
12
0
300
weigh
00
10,5
3,8
13
12
1
350
weigh
00
3
1,3
28
14
57 69.1
151
0.5
105
1
131
52
~elgh
no
2
1
2,7
1
24
24
0
500
~eigh
00
115
23
13,5
0,5
0,8
1
1
1
3,6
607
4
199
25
21
4
600
weigh
00
8
8
0
700
weigh
00
5
5
0
800
welgh
00
00
1
1
0
900
weigh
26 48.9
.'
31
121
38
336
294
42
Tol wel % weig Tot no
00
38,9
7
11,9
1
182,5 4,021
3,8 0,084
38
1
15,2
1 19,2
1
2,3
1S
17.7
2
2 30,5
1 129
3 46,4
1
1
37.1
13,5
2.8
92.7
146,5
0,817
0,297
0,062
2,042
3,228
3
1
3
7
2
607
233 1261
9,4
768
2
123
13,5 0,297
12 4538,8
7
1261
4.4
3
1
PI.uron.cllform. .
Bothldl.
PI.uron.clldu
t1ippoglossoldes 6
Glyploeephalus
Pisces
TOlal
43
41
2
400
177
792
55 91,6
reble 3
K.lt.g.1
Total aamples
No wilh lood
No empry
SiZllClollS
Food lIems
3
3
0
100
welgh
15
14
1
120
110
weigh
78
68
10
150
welgh
110
82
70
12
200
weigh
110
81
71
10
250
weigh
no
91
83
8
350
82
72
10
300
welgh
no
weigh
no
96
90
6
400
weigh
no
40
39
1
500
no
welgh
41
38
3
600
welgh
no
13
10
3
800
27
24
3
700
welgh
110
~eJgh
no
653
586
67
4
4
0
900
weigh
no
Tol welg % weigh Toll1o
no
tNEATEffWES
Polychull
Aphrodlle
Polynoldae
Phyllodoeidae
2,2
Molluscs,
ßivalvla.
Gastropoda
Bueelnum
Nuculana
Turritella "
Loliginld
Loligo ap
5 6,65
0,2
0.9
0,03
0,2
0
18 11,8
1 0.7
0,8
5
1
1
2
0.7
40,1
4,8
8
8
5
2,3
14
7
8
7
27
1 18,5
12 131
1.7
3
23
1
1.3
132
0
1
23
1
213
0,5
27
2
2
1
2,7
Cruslaclii
Cumacea
Diaslylidae
Myslda
Mysidae
Schislomysls ap
Amphlpoda
Gammaridea
Ilyperiidae
CaprQllidae
Phlhisica marina
Euphasllda.
Meganyctiphanas norveglea
D.capoda
Colridea
Pandalidae
Pandalus montagul
Pandalu s borealis '
Pandalina brevlostrJs
Processa sp ,
Processa nouvell hollhulsl
Crangonldae,
0,2
Crangon sp,
Crangon crangon
Cral1gon allmanl '
Ponlophilus sp
0,1
Ponlophilus aplnosus
0,1
1
1,4
0
0.1
10
1
0,4
8
0
1
2.4
1
0,2
2
1
0
0,3
22 '
1
0
1
2,1
0,3
0,3
10
0.3
1
0,05
1.2
16 0,1
2
2
4
0.1
0
5
0
4,9
4
53 14,3
1,3
4
0,4
4
2,2
1
0.7
0,05
2
1.9
50 6,4
8
1
9
53
1
3
6
2,9
1
1
1
1
8
15.7
5
6,6
2
0.1
1
4,3
2
0,3
1,8
1
1
0,5
1
2.8
0,6
4
1
2,3
12,1
1
2
1
9
0,1
1
1.2
1
5
19
6
17
2
0
24
32 23,2
100 70,3
0,6
4
4
1
0,7
0.4
1,4
4
0,1
3,8
5
1,5
4
48 - 0,9
1,1
0,8
1
9,2
7
0.05
1
147 22,1
467
71
4
2
3
41,2
189,2
1.7
0,03
0,441
2,025
0,018
0,000
78
64
7
1
23,3
555,81
4
0,9
0,2
3,8
3,3
3,8
0,249
5,948
0,043
0,010
0,002
0,041
0,035
0,041
7
104
4
2
1
6
2
1
2,4
0,026
1
6,1
0,065
0,3
0,1
0,003
0,001
0,1
0,001
0,05
0,001
33
1
2
22
5
1
0
24
1
12
30
1665
11746
23
16
2
5
3
15
1
39
200
3
14
95
40
1
1
0
0
0,5
8,7
0,4
0,7
1
7
2
0,6
0
0
2,6
33 34,7
1
0,4
0,2
6
1,7
19 40,3
1
3,8
Prlapullda
Pripulus
2,5
5
12 64,6
1
10
143 47,7
457 176
0,5
2
1
20 86.7 564 51.4 344 25,6 156
255 22,3
953 336 2031 455 2728 334 1510 379 2437
4 0,21
2
1
0.9
1,1
3
3,4
0.3
1
1
3,8
2
1
2.3
0,9
4,2
1
1
1
0.1
1.4
0,1
1
1
0,8
6
12 '
1
2
2
1,7
21
8.2
7
7
1
2,5
4
7
6
17
0.1
8,6
0,2
1
12
1
1,5
1
0.4
1,7
0.2
0,8
9,6
0,7
2
0,6
9
1
1,7
1
14 11,2
3
2
0.3
2
2
11
1
2
e,i
1
2
1,2
2
159
633
56,S
3,044
284,4
377 2059,6 22,042
0,066
6.21
3,5 0,037
3,7 0,040
0,096
9
6.5 0,070
1,3 0,014
0,05 0.001
9
0.096
18,6 0.199
1.3 0.014
5,25 0,056
56,9
0.609
0,015
1.4
1,5 0,016
- - - - - - - - - - - - - - - -----
-----------
Teble 3
Kallegal
Tolal sampies 3
No wilh load
3
No empty
0
Sizeclass 100
welgh
Food i1ems
Reptanlla Nephropldae
Nephrops norvegica
Anomura
Paguridae
Pagurus bernhardus
Calocaris sp
Brachyura
Porlunidae
liocarCJnUs sp
0,2
L10carcinus holsalus
liocarcinus depuralor
Ellalia sp_
Majidae
Ophlurolda
Ophiura 6p
Ophlopholis aculeala
Amphiura sp
Unid. malerial
Planlmalerial and algae '
no
15
14
1
120
78
68
10
150
~elgh
no ~elgh
2,2
0,4
2
0,1
82
70
12
200
welgh . no
no
0,3
1
1
2,5
1
4
0,7
0,7
1,1
1
1
3
1
6
1
0,5
1,23
3
12
4
0,5
0,6
4
1
9
81
71
10
250
82
72
10
300
~elgh
no. welgh
welgh
no
3,4
5,2
4
3
3,7
2
1,9
4
2,7
3,4
6
3
2,8
1
3,4
2
1,1
0,4
1,2
91
83
8
350
8
2,5
16,9
2
1,2
0,2
9
1
0,7
0,5
~el9h - no
no
welgh
1,3
1
4,6
20,S
5
1
3,7
4
1,9
11 31,S
1
2,7
3
6 37,8
14 172
2
19
1
9
50
14
145
4
29
8,8
15
0,2
1
30
1
0,5
1,9
2
5,7
19,7
3,1
Gadldaa'
Merlangius merlangus
Melanog,ammus eeglefinus
Pollachius sp
I
Trisoplerus esmarckiil
Enchelyopus sp
I
Merluccius merluccius
3
2
1
26,9
91,7
44,2
0,4
2
6
2,3
6
1,3
2,6
3
7
10,4
1
5 20,3
7 114
4 25,6
3
7
2
298
9
3 30,6
1 22,3
2
2
1
0,8
2.4
1
7
1
41,6
3,7
116
27
24
3
700
weigh
no
2
13
10
3
800
~eigh
no
4
4
0
900
weigh
no
653
586
67
Tal weig % weigh Tol no
no
1 40,8
31,4
8
3
183,9
1,968
1,7
1,1
2
1
3,1
2
17,8
27,S
4,5
54,4
21,2
17,2
83,3
733,5
0,5
0,4
0,190
0,294
0,048
0,582
0,227
0,184
0,891
7,850
0,005
0,004
16,93
1,4
2,9
5,8
0,181
0,015
0,031
0,062
84
5
10
23
3,6
2,4
0,039
0,026
0
0
10,4
0,111
1
1,405
131,3
1068,4 11,434
97,8
1,047
22
41
11
1,473
9,000
0,120
0,367
1.176
1,337
O,291
7
27
1
1
9
4
1
1
4
15,5
15 134
8,4
1
2
21 90,8
2
0,5
2
3,7
9
0,7
5
94,6
33
165
43
216
67
72,S
15
8,8
1,3
19
5
1,1
1,5
4
2,5
0,2
7
1
0,4
1
6
2 59,6
17
92
5,8
79,6
139
11,2
2
5
1
20,9
1
31
20
34,3
16,8
71,2
20,9
0,4
1
0,017
42,6
0,7
15,9
619
1,6
2
0
17
0
18
8
4
59
9
9
22
159
1
2
3
11
0,5
2,3
294
Callionymidae
Callionymus sp
Gobldae -.
Goby
Aphla minuta
5,7
1 56,8
2,5
3
1,5
7,8
4
4
8
3
FOt
Myxlnldae
Mv.ine
0,4
welgh
4
0,1
Clupeldae
Clupea harengus
Sprallus sprauus
no
37
3,8
52,3
41
38
3
600
2
2,5
0,2
2
6
40
39
1
500
5,7
6
1,7
7,4
1 13,5
10 50,9
0,4
96
90
6
400
4
4
1
2
90
2
3
2 23,9
1 45,8
2
2
27,2
1
137,6
841
11,2
34,3
109,9
.124,9
27,2
3
1
574,2
6,145
173
17,2
5,6
0,184
0,060
43
19
1
2
1
8
44,8
2
Table 3
Kellegel
Tolal sampies No wlth lood
No emplySizeclass
Food Items
3
3
0
100
welgh
15
14
1
120
no welgh
00
78
68
10
150
welgh
82
70
12
200
00 welgh
81
71
10
250
no ~elgh
no
82
72
10
300
weigh
91
83
8
350
weigh
no
40
39
1
500
welgh
96
90
6
400
~elgh
00
no
Agonldll
Agonus
Pholldlda.
Pholis gunnellus
Zoarcldll
lycodes sp:
lycodes vahli
Pieuroneclllormes
BOlhldae
Pleuronecllda.
limanda Iimanda
lIippoglossoides 6p
PlalichlhyS
1,4
0,9
1
1,3
1
1
Soleldae
Solea solea •
EggsPisces
Tolal
0.5
28 5,65
76 41,3
234
0,1
104
1
351
0,5
303
2
770
0.4
427
2
796
3,5
1
24,8
3
4
1
0,7
13,6
1
1
41
38
3
600
weigh
no
27
24
3
700
welgh
no
no
653
586
67
Tol welgl % weigh Toloo
no
0,166
2
1
20,3
0,217
2
43
24,8
0,460
0,265
6
3
212
22,6
187,8
480
108,1
450
2,269
0,242
2,010
5.137
1,157
4,816
15
2
18
14
11
6
58,7
0,628
1
5,6
41,4
9344,1
0,060
0,443
0
24
15173
1
16,8
5,4
1
5
7,2
1
2
1
1,3
1
70,6
4
93
2
2 33.6
27,3
1
8
3
2
57,8
226
62,7
105
5
5
4
1
58,7
1
6,5
no
4
4
0
900
welgh
15,5
10,1
35.8
9,4
30,1
13
10
3
800
welgh
61,5
22,6
22,2
99,3
15,2
123
5 42,5
2
1
3 91,5
2
1 152
5,6
6,4
7,8
4 10,5
4
1 12,1
3
5
2.6
895 1453 1629 2348 1628 3440 2047 1946 1326 2682
1
751
2 34,1
2
1
1 50,7
2
667
186
1
362
33
41
14
15
<150
150
200
250
24
11
13
350
400
10 0
90
a0
70
,
60
50
40
30
20
10
300
500
600
>-700
predator length class
Figure 1 a
Percenta<;e dlst:!b.ltlCXl of food itars by 'oei<;ht/c::xl predator slze class in Ska<;eaak
50
91
54
10
12
<150
150
200
250
13
43
350
400
24
14
25
100
90
80
70
60
\
50
40
30
20
10
300
500
600
>-700
predator length class
F'igure 1 b
?eroa~tage distr~ticn
of food items by weight/cod size class in Kattegat
90
80
ijjllijilii~~
1::12
t1I~l~
r-.:~::"??.?~:~
\
50
40
30
Zoarcidae
ES Gobidae
~~~:~~if::
:s::;::;,;~"'.:.
70
60
fish
~ ?leuronect.1fonnes
18
100
B!I Cther
o
I
call10nymidae
== Gadidae
EI Ciupeidae
BI ~chinoder.nata
20
10
0
<1 5 0
Figure 1 c
150
200
250
300
350
400
predator lenqth class
500
600
>-700
mCrusucea
o t'tlllusca
•
?olyc:h.>et:a
Pe=cent:age dist=ibution fish prey Gy weight/cxl size class in the
100
90
80
70
Sea
11
f:ill ether
~tml
60
%
:-brt~
lIl?leuronectifor:nes
:!11
50
EI Arnrnocytidae
I'
40
o
~tfu~
30
Gad.1dae
~<~~,<.:
~"'.~~
~'1
20
10
~t~t~~
0
<1 50
1 50
20 0
250
300
350
400
500
600
>=700
predator lenqth class
Figure 2 a
Percentage distribution of fish prey Gy we1ght/cod size class in Skagerrak
100
90
== ether
80
[] Pleuronecc1formes
70
60
%
11II
Z04rcidae
50
40
30
o Gadidae
20
10
•
Clupeidae
8
ether
[]
?leurcnec~ifo~s
o
<150
150
200
250
300
350
400
500
600
predator lenqch class
Figure 2 b
Pe..rrenta:;e distrituticn of fish prey by weighc/cod size class in Kattegat
100
90
90
70
,
60
11 zcarcidae
50
40
30
20
10
o
<150
Figure 2 c
l
150
200
250
300
350
400
predator lenqth class
500
600
>-700
o
Gadic!ae
•
Clupeidae
Per~e..'1t:ac;;e
distribution of c.."'UStaceans by '...eigne/ cod length class in t!:e
North Sea
100
~ Oeher
90
80..J....=='"
III
3rachyura
70
~ Anomura
60
so
Nephropidae
40
11 Crangonidae
30
I
20
10
o
<150
150
200
250
300
predator
Figure 3 a
350
le~gth
Percem:age distribution of crustaeeans by
400
500
600
>700
EI
Pandalidae
o
Euphasidae
•
Amphipoda
cla~s
~ght /
ccd size ciass in Skagerrak
100
~ Other
90
rn 3rachyura
80
70
E3 Anomura
60
%
so
EI Nephropidae
40
BI Crangonidae
30
20
8]
10
?ardalidae
o Euphasidae
o
<150
150
200
250
300
350
400
500
600
>-700
•
Amphipoda
predator length class
Figure 3 b
Percentage distribution of c.rustaceans by weight / cod size class in Kattegat
100
90
80
\
70
m9rachyura
60
~
50
Anomura
[] Nephropidae
40
JO
111 Crangonidae
20
Im
Panc!alic!ae
10
o
Euphas idae
•
Amphipoda
0
<150
Figure 3 c
150
200
250
300
350
400
predator lengeh class
500
600
>-700
Mean weight of stanach content/cc:d size class
6
.•- North Sea
ln
0- Skagerrak
.+-
<-50
Figure 4
150
200
250
300
350
400
predator lerqth class
500
600
>:700
Kattegat