sh_vol09_04_1948.pdf (608.3Kb)

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i " i % S K E % g % D I R E K T O R A T E T S S K R I F T E R

S e r i e E - l a v u n d e r s ~ k e t s e r

(Reports on Norweginfz Fislzery nfzd Marine I#tvestigntions) Vol. I X . N o . 4

P u b I i r i ~ e d b y t h e D i r e c t o r o f F i s l r e r i e s

Some Observations on the Food of Cod

(Gndus

callarias L.) of the 0-11-group from Deep Water and the Littoral Zone in Northern S o r w a y

and from Deep Water at Spitzbergen

1 9 4 8

A.s John Griegs Boktrykkeri, Bergen

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CONTESTS

Page Material . . . 5 Methods . . . 6

. . . Food of the 0-group of cocl fi-oil1 deep water '7

. . . Foocl of the I-11-group of cod fl-om deep mater '7 Food of the 0-I-group of cocl froin the littoral zone . . 10 Discussio~~ . . . I 1

. . .

Reference 1 2

. . .

Tables 13

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MATERIAL.

1)uring September and October 1946 salllplcs of cocl oi the O-II- group were collectecl in Northern Norway. They \$?ere caught partly on the trawling grounds with a prawn trawl, partly ill the littoral zone with a young-fish seine.

On July 16th one sample of cod of the I-11-group was taken in prawn trawl on the trawlillg ground Rekesmyla a t Spitzbergen.

The material was collected for the pmpose of studying racial differences between the coastal cod a n d the arctic cod, but in some localities (fig. 1) il-~vestigations were also made of the stonlach content.

Fig. 1. Localities in Northern Norway where samples of cod of the 0-11-group wliere taken. September-October 1946.

+

In the littoral zone.

I n deep water.

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Il'lie material was preserveci in 4-10 percent formalirie -\ritil the addition of sollie SaC1.

From cleep water a total of 167 stomachs of cod of the 0-group and 74 of the I--11-group -\tlere examiiierl, and from the littoral zone 66 stomaclis of cod. of the 8-group were investigated. As maily of the cod from the trawling 9.1-ouncls had turliecl the storna.chs insicle out when they came out of the water, no attention was paid to the number of eiilpty stomachs, and only such illclivicluals which hacl stomacll coriteats, were investigated.

For the eiiumeratio~l of the euphausiids the eyes were counted (Bro1v11 and Clle11g 1 946).

Soiiie of the orga~lisiiis were so much clissol\~ecl that they could not be ideniifiecl fm-ther than to groap or family.

A complete list of the food species fouricl in the stomachs of cod of the 0-11-groul~s is given in table

V

(page 117).

No.

%

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FOOD O F THE 0-GROUP O F COD FROJl DEEP \T;r?TER.

I n fig. 2 is shown the food of cod of the 0-group from some trawling grounds in Northern Norway. (Table I , page 13).

The main content of the stomachs consistecl of ci-ustaceans. The euphausiids range first both in vlu~liber a ~ l d frequency, the number per sto~nacfr being about 5, and they occur in 73

%

of the stoniachs i~ivesti- gated. I'lzysa.lzoessa inern.zis is most often met with.

The copepocls range sec~vlcl ill ~ ~ n r n b e r and frequency. Owing to their slnall size, ho~vever, they are of less ivnportavlce tl:an the followillg groups.

The amphipocls are next in ~luinerical importance. There are several species, hut Halji~nges fzzlvoci~zcfzis a11d Xnchoiropi's lzelle~~i a.re lnost com~non.

Of the decapods Pn?zdnlzis borealis is the most important species, of the rnysicls Eryihvofis c~/yihro$htalma and illz'chtcii/~y"is ~ ~ z i ~ l a .

The renlaiilillg groups of food orga~lisrns are of ~lliilor importance.

FOOD OF THE 1-IT-GIZOUI' O F COD I-3ROM IIEEP WX'TER.

'The cocl of the I-11-group from cleep water has about the same diet as that of the 0-group, with the euphausiicts ^aithe lnaln food, but other crustaceans, especially alnphipods, isopocis, clecapucls and mysicls ilow play a greater part (fig. 3, ancl table 11, page 14). The copepods are scarce.

TAI3LE 1.

l'lie stonlac11 collteilt of cod of the I-11-group lroill a tra\\r!ing grouncl a t Spitzbel-gen, July 1946.

Number of foocl organisms in all the stoinaclls investigated.

111 ( ) the number of sto~llachs in ~vhich the different 01-gallisms are fouilci.

- --

of

--

I-

Spitzbeigen

-

I

'

S u ~ l l b e r of organlsm5 per 10 stomachs Percentage of frequency

l pycnogonld.

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No.

,%

Fig. 3. The food ol 30 cod of the I-11-group from some trawlmg grounds In Kortheril hTorway. September 1946.

At Spitzbergez~ (table 1) the cod of the I-group feeds most exclu- sively 011 amphipods which are found in great numbers in all the stomachs examined, averagely 12 per stomach. The domi~lant species is Eutize~nisto libellz~la. The other groups of food organisms have all about the same percentage of frequency, except the euphausiids and copepods, which are scarce.

I n Lauksund some cod of the 0-I-group were caught with a prawn trawl a t a depth of 50 m, on a bottom with gravel and sancl.

As one would expect this cod had a cliet different from those living on the trawling grounds, where the bottom consisted of mud.

Fig. 4 shows the compositio~l of the stomach contents. The cocl of the 0-group feeds mostly on copepods and decapods (see table 111, page 15). The copepods are nearly all harpacticids, mainly Idyaea fz~rcata k~hich occurs in great number, averagely 100 specimevls per

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- 3 -

No

00

7

70

6 60

5

50

4 4 0

3 30

2

2 0

I

10

O 3 b - O Z ? 3

-

.< O t Q @ Q

0 m

':,,*

Q ^{- '} % m t Q r , m %

3

g

^.^, ⁰ ^-0

c ' "

(D

0 O Q O P

- i

^~

Q P Q I

TJ (D

CD P

V,

Fig. 4. I h e food 01 33 cod o! the 0-I-group from Lauksuncl, Northern Norway.

Depth 50 111, bottom gs-avel and sand. Septesnbel- 23rd 1946.

stomach. Of the decapods Pandalus wzontagui ancl P. pro$inquus are the most conzmon species.

The cod of the I-group seeills to prefer somewhat larger food organisms. The copepods are lacking in the stomach contents. The decapocis play the greatest part, but other groups of crustaceans are also repre- sented. Fishes are more common than in the stomachs of cod of t h e 0-group.

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I

^{N o}^per¹⁰ s t o m a c h s

1

O O ' P 7 ~ 0 , ~ W P

~ ' f o n ; u ~ ( D- 3 - <

Q 5 0

Q U 2 J m c n -

⁰ ^. ^m ^:

" Q Q o 7

p

9'

^P

Q p,

6' 2.

^Q

-.

Q ³

u ^(D

rn Q

ul

Fig. 5 The food of 66 cod of thc 0-group fro111 the littoral zone in Gauswk and Bergsfjord, Norther11 Piorway. September 194b.

FOOD O F COD O F T H E 0-GROUP I N T H E LITTORAL ZONE I n shallow water the foocl of cod of the 0-group nat-rtrally differs from that of the cod in deep water. In fig. 5 is shown the cornposition of the food of sonle cod of the 0-group from the littoral zone is1 Gausvik and Bevgsfjord (see also table IV, page 16).

Numerically the copepods range first. Both pelagic and bottom- dwelling species are fou~ld in the stomachs, but the harpacticids are most common, especially Flarpactic?ls ztniremis.

The polychaetes are not so numerous, but nevertheless frequently met with. They were difficult to identify, lrtut some of them probably belonged to the genus Lefiido~zottfis.

The amphipods range second in number and frequency. There were

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different species which were only partly iclentified. Ganz~~zar~ts sp. seems to be rliost common.

Isopods were also present in the stomach contents.

Together with the polychaetes the crustaceal~s form the iziain foocl of the cod of the 0-group in the littoral zone.

DISCUSSION

The material of cod of the 0-11-group is salliplecl in the course of 2 inoliths ancl therefore naturally of restricted value for a general iilvestigation of tlie food orga~iisms. The rrurnber of sto~nachs esarniliecl is also so small that general conclusioiis cannot be dralml.

Nevertheless there some is maill features which must be paid attention to. 1)ifferent groups of cr~rstacearls form the main part of the foocl of cocl of the 0-11-gro11-p both in shallow ancl deep water. ⁰¹¹tlie trawling grorillcls the euphausiids, especially Tltysa~toessa i~ z e r ~ i ~ z i s , are of special importance as food. Brown and Cheng (1946) point t o the fact that around Bear Islalld large cod feed mainly on this species during the surnrner months.

'She same alltors also nnentioli that Euthe??zisto libellula in August 1.930 formeel the principal food of the cod on the Bear Islancl gro~ulds.

I t will be renleliiberecl that the cocl of the I-group caught at Spitzberge~i or1 July SGth, 1946, had mainly eaten Ezrtlzervzisfo libellztla.

Since the e~~pliausiicls form an important part of the food of the cod, they are probably not entirely plarlctonic, but must in periods keep t o the water layers near the bottoii~.. One niight also assume that the cod a t intervals leave the bottom and search for foocl in the water layers some clistaiice above the bottom.

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BROWN, W. 74'. ancl C. CHEXG 1946. Investigations into the food of the cod (Gadus callai~ias L.) off Bear Islallcl ancl of the cod ancl hacldoclr (C;. argle- f i n z ~ s Id.) off Icela11~1 and the M u r ~ n a ~ l coast. Hulls Bulletins of Marille Ecology, Vol. 111, S o . I S . Hull.

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T-%BI,E I.

Tlie stoiliach content of cnd of tlie O-group from come trawling jirounds in Xorthern Sorway, Sey)tes~~ber-October 1.946.

Niimber o f food organisi~iri in all stomachs iri\.estigaie(l. 111 ( ) tlie ilirn~ber of stoiliachs i11 \vkicli tlie differeilt 01-ganisms ai-e foiiiitl.

. ~ h...-... ~ -. --- . . ~. ^-~^- ^- ^~- ^~~ . ~-

Locality

V5gsfjord--Astafjoril . . ^.. 1 Bygdenfjord. . . . . ^.. ^.. . . . ^..

l

Iivænailgeii, Skorpa . . . W

Porsangerfjorcl . . .

.

. . .

Total . . . 1 5

Nuniber of organisms per 10 stoinachs .

.

. . . . . Percentage of frequency

.

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'XBL,E 11.

Tlie stos~iach coiitcrit o1 corl ol the J-Il-group from sornc trawliilg grouslds 111 Northern Norway, September 1946.

Nuniber of food organisslis in all stoi~iaclis iiivestiga.ter1.

In ( ) the nuinber of stoniachs in wbicli tlie differeiit organisms are fouiicl.

Locality

. . . I<v;~slangesi, Slroi.pa

Balsfjord . . .

Ba.lsEjord . . .

.

- . -. ^-^p-. - - --

Total . . .

S o .

«I' cod

Leiigtli, inrn

-

!

^I

- ( 1 )

- 1 -

~

^{( l )}

6 2 i51 .. ( 2 ) _.

6 4

(5) (4-1

... ...

l

'u'riinbev of organissms per 1.0 stos~~nchs . . .

1

^7.7 ³⁰ ¹¹ ^6.7 ^25.3 ^l^..i

~

^0.3

ⁱ

.

l>erceiita~e of Irecliienc). . . . I 27 SO ' 3.3.3 1 36.7 30 3.3 3.3

1

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'L'-\ HT>i< I l I .

The stoinach conteilt of cod of the O-T-group from ILa.uksui~cl, Nortlierii Norway, September 23. 1946.

Depth 50 m, bottoin gravel and sand.

Nuinber of food 01-ga.iiisins ill all stomachs investigated.

I n ( j the rri~inber of stoinachs in wliich tlic cliffererit orgailisrns are fonild.

- - .-.- ^-^P^-

No.

l I

Number of organisms per

I

10 stomachs . . . .

.

^{. . .} i

1

^2.4

1

^-3.3

^!

^-

Percentage of frequency . . 76 24

1

¹²

l

i

^I

i

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The stomacli content of cod of the O-group caught in the littoral zuile in Xorthern Norway September-October 1.946 Number of food orgailisms in all stoniachs iiivestigatecl.

111 ( j the number of stoinachs in which the different orgailisnis are foui~d.

. . .

Percentage of irequcilcy 1.2 7.4 17.9 11.5 44.7

;

^O.? ^0.2

1

^1.7 ^12.7

/

^1.1 ^0.4 ^0.h

l l l ^l

.

- ~ -- --

1 ^d

Lacality

..----p- --- p ....

. . .

P

Gausvik cn

I

Bergsfjord . . .

( l ) -

.. - . .. ^p.... - ..

Total . . . G6 S 49 1-18 1 76 295

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1

⁽²²⁾ ⁽¹⁶⁾ ⁽¹⁾-- . . . . .

Number of orgailisms per 10 stomachs

...l

^11.9 ^15.1

1

^59.0

/

^33.3 ^24.3

1

^1.5

/

^1.5

/

^12.1

1

^63.5^l ^9.2 ^3.0 ^6.1

l l

l

l l l

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T A B L E 11.

The food of cod of t h e 0-11-group froin t h e littoral zone (Gausvik alici Rergsfjord) and from trawling groulids in Northern S o r w a y a n d Spitsbergen in t h e

a u t u m n of 1946.

MEDUSAE:

. . . Medusae reinains.

CHAETOGSATHA :

Sagzttn sp. . . .

POLYCHAETA

L e p l d o ~ o t u s sp. a n d others . . . x x Z'onzopter,zs sp. . . . - -

INSECTA inclet. . . . X

I I

C'O13EPODA:

C a l n ~ z u s fil~w~cwchicus (Gunn.)

I

i

. . . . . .

? C l c i ~ ~ i d i u s nifinatus (Boeck) ^-^- B v y n x i s bveuicoi~?zis U n d i ~ z o p s i s brndyi G. Boecli 0 . Sars . . . . . . -

-1 I

^-^-

Undi,nopsis si~izilis G. 0 . Sass . . .

Stephos sp. -

Ce?zt~~opagrs lznmatus (Lilljeborg) x . . . C a ? ~ d a c i n sp. . . .

A cnvtia clazisi Giesbrecht . . . Oitlzona Izelgola?ndica Claus . . . X

Hevvnarzelln sp.. . . . Ecdircosonrn sp. . . . ^-:<

Hnvpacticitr f ~ n i r e i i s Iirwyer .

.I -1 ^,

Tdyaerc fi:vcata Baird . . . /

-'

^-

Copepocla indet. . . .

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- i 8 - Table 5 (cont.)

ANOMURA:

LEPTOSTRACA:

P\IYSIDACEA:

Ei,yt/rvo$s sp. . . . Stiloniysis g i ~ a i ~ d i s (Go&s) . . .

. . . Pvnzr~zus illel/inis (Rathlie)

P Y ~ I U P ~ L I S / l e . ~ z ~ o ~ z t ~ (i\'tiiller) . . .

EUPHAliSIACEA:

IIECAPODA:

AA1IPHIPODX :

? Pcriculotbes sp. . . .

Plzoxoccplznl~rs lzolbolli (Icriiyer) . . . .

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---- 19 ----

Table 5 (cont.)

. -

W

- - --- ~ --

RacJ~olrobis I~elleri (Boeck)

. . .

G a m m a v ~ t s sp.

? Jassa sp. . . .

Corop!riul,z sp.

. . .

CheZura sp.

. . .

Podoceridae

. . .

Capsellidae ,

. . .

Amphipoda indet. . . .

I

TSOPODA:

! I 1

? L i l ~ l ~ l O ~ ~ Sp. . . .

? Leptopzathia sp.

G~zatl~icc oxy zrren (1,illjeborg)

. . .

Mu?znopsis lypica M . Sars

. . .

Jaera ~ l b i f i , m ~ s Leach

. . .

^'

? J u n i v a sp.

. . .

Csyptonisciclae

. . .

'Tanaidae

. . .

lsopoda indet. . . . PYCNOGONTDA

. . .

CIKRIPEDIA:

- - - - x - - -

x - - -

I x

X

Balnnus nauplins

. . .

^- ^X

Ralanrrs cypris

. . .

^{- - y}

I ⁱ

PISCES:

Cottns sp. . . . ^,

. . .

L ~ i r n p e ? ~ u s sp. . . .

Gadus callarias Id. . . .

. .

Hifipoglossoirles platessoides Fabr.

? Gobiz~s sp.

. . .

Pisces indet..

. . .

-

x

X

-

/

-

>:

- - - - X - - -

x - - - . - - -

-

-.

- - -

- - - -

X -

-

X

-

i < - - - . . -

- I X ^{- -}

- ~ - - - - x - - -

x

-

sh_vol09_04_1948.pdf (608.3Kb)

Some Observations on the Food of Cod

callarias L.) of the 0-11-group from Deep Water and the Littoral Zone in Northern S o r w a y

and from Deep Water at Spitzbergen

+

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