CM_1970_H_33.pdf (571.4Kb)

This paper not to be cited without prior reference to the author.

International Council for the Exploration of the Sea

C.M.1970/H: 33

Pe1agic Fish (Northern)Committee Ref:

Demersa1 Fish(Northern)Committee

Preliminary Report

of joint Icelandic-Norwegian investigations in the

area between Iceland and East Greert1and in August 1970.

Int:t,bductibn

A joint Icelandic-Norwegian survey was carried out

i ...

11 of AUgUst in order to investigate the distributiQn

Of

pelagic fish (including O-group fish) in the area between Icei~d and

East

Greenland. The arrangement oh the detailed program was ~eached at

a

meeting in

I , '

Reykjavik on 1 August and the survey

Was

^condu~ted with two research vessels.

On 11 - 12 August a meeting was held in Akureyri in order to combine the observations and to prepare a preliminary report. The participating vessels and the scientific and technical staff were:

'R/V "Arni Fridriksson" ^I

A. Vilhja1msson, SoA. Schopka, So Lydsson, G.Sv. Jonsson, H. Ho1svik, E. Fridgeirsson.

R/V "G.O. Sars^ll,

O. Dragesund₁ E. Bratberg, J. Blindheim, T. Jakobsen, B. Myrseth, I. Hoff, A. Storler, S. Agdestein, ~. Torgersen, Po Eide, F. Kje1strup-Olsen,

O. A1vheim. S. Lygren# I. Huse.

Program ,and methods

As will appear from Fig. 1 "G.O. Sarsll covered mainly the banks off

East Greenland and the Irminger Sea, whereas IlArni Fridriksson" surveyed the area off West and Northwest Iceland. The technique and methods applied was a combination of echo sounding and fishing with pe1agic trawl

(Dragesund, Midttun and Olsen 1970).

General outline of results

Most of the recordings are due to O-group fish, but in addition medusae and other planktonic organisms contributed to the echo-abundance. Further- more adult cape1in and probably blue whiting or Norway pout were recorded

in an area NW of Iceland (Fig. 2). This report is of a preliminary qharacter because i t has not yet been possible to work up, the large

~ateria1 of data collected. Such investigations have never been carried out before in this region and therefore i t is impossible to make any

fi~ conclusions about the abundance of O-group fish.

2

Hydrography

Horizontal distributions of temperatures at the depths of 6, 50, 100 and 200 m are illustrated in Figs. 3, 4, 5 and 6. Salinity distribution at 6 m depth is illustrated in Fig. 7.

Two hydrographic sections were worked by IG.O.Sars", i.e. between Ocean Weather Station Alfa and Cape Tordenskiold (Fig. ⁸⁾ and from Cape Dan

towards southeast (Fig. 9) ⁰ From Latrabjarg westwards one section was, worked by "Arni Fridriksson ¹¹ (Fig. 10).

The highest abundance of O-group fish was found inside the cyclonic cir- culation of the Irrninger Current. The most dense consentrations were observed at depths between 20 and 50 m in the area with temperatures exceeding 9!5°C extending westwards from the Icelandic Continental Shelf

(Figs. 3 and 4). Along the East Greenland coast navigation was prevented by ice at a distance of approximately 25 nautical miles off the coast.

Capelin

Adult 1-3 years old capelin were found outside the Continental Shelf to the northwest of Iceland (Fig. 11). The capelin were recorded in depths from 250-200 m at day and 75-30 at night. previously adult capelin have never been located so far west, but mainly in the area

80-120 nautical miles due north of Cape Horn as well as north of Kol-

beinsey and to the west of Jan Mayen. Icelandic fishermen believe, however, that Icelandic capelin migrate as far south as Latrabjarg, but this, to our knowledge has never been verified.

I t is thought that the capelin populations off Iceland and East Greenland are not panmictic to any mentionable degree and vertebral counts of

capelin from west Greenland and Iceland certainly show a difference of

1.0 to 1.3.

±celandic capelin spawn at temperatures between 4 and

7°c

and i t is un- likely that such temperatures are ever attainable at East or west Green- land during February.May~

O~group capelin were found to be scattered over a wide area off west Iceland, (Fig. 11) and moreover in a limited region some 100 nautical miles south of Cape Dan. The distribution pattern may, however, be abnormal since practically no capelin spawned to the west of Portland this year.

Considering the length frequencies of O-group capelin there is a marked if not meaningful difference between C I and A XI on one hand, and G XI on the other. This can either indicate an earlier spawning of the East Greenlandic capelin or possibly the earliest larvae from the Icelandic ^I South coast spawning drift to this area.

3

Blue whiting and Norway pouto

Some dense concentrations were recorded in an area between 65°30' to 66°00 ' N and 27°30' to 28°30'W (Fig. 2). To identify the echo recordings^l fishing experiments were carried out, but they failed due to difficulties in operating the trawl. I t is suggested that the concentrations consisted of blue whiting or Norway pout.

O-group blue whiting was distributed over the northern half of the Irminger Sea (Fig. 12). The highest concentration was at 63°20'N and 26°30¹W. Great quahtities of O-group Norway pout were caught off Snrefellsnes and Latrabjarg~

Redfish

Redfish were widely distribut~d bver the whole area excepting more

coastal waters off West Iceiarid (Fig~ 13) ~ I t was not possible to trawl in the central part of this area but echo abUndance there was high. The richest trawl catches were made 120 nautical miles west of Sn~fellsnes

and the density on 63°201N and 26°30'W was also high. The northwestern and northern limit of distribution seems to be in correlation with the 4_6° isotherms (Figs. 4 and 13) but the distribution pattern may equally well be decided by the bottom topography of the area.

Cod and haddock

Only a few examples of these commercially important species were recorded to the northwest of Iceland (Fig. 14). Possibly, the reason is, that the main O-group population has already reached the North Iceland coast as

indicated by previous Icelandic investigations (Einarsson, unpublished).

Catfish, blue ling and Greenland halibut

The catfish had a scattered northerly distribution, and the blue ling were spread over the eastern part of the area as well (Fig. 15). The O-group Greenland halibut (Fig. 16) showed a wide scatter, more or less over the \'\Thole area.

LUmpsucker and sand eel

These species (Fig. 17) are only found in the eastern half of the area investigated (30⁰W). On the stations, where lumpsuckers were observed they were equally scattered. Thus, only 3-8 specimens were caught per stationl ranging in length from 50-100 mm. Possibly alle these do not belong to the O-group fish since the size is so great but this remains

to be proven. The highest concentrations of sand eel are in shallow waters of Sn~fellsnes. The length range is 45-115 mm.

4

Invertebrates

Small squid with mantle length ranging from 1-5 cm were caught at nearly all the trawl stations and appeared more or less evenly distributed in the area. Aglantha digitale was taken at many trawl stations. Its highest abundance was in the western half of the area. The scyphomedusa Periphylla was found throughout the area^o Its greatest concentrations were in an

area between 64°001N to 65°30^lN and 30⁰W to 34°30^lW. There one trawl haul gave a catch of 50 litres (188 specimens). The distribution of Aglantha digitale and Periphylla is the same as that observed during

the Norwestlant 3 Surveys (Brainbridge and Corlett 1968)0

Concluding remarks

Adult capelin were recorded in a limited area off East Greenland near positicn 64°N and ^34~36°W. There a small patch of O-group capelin was, also observed^o I t is difficult to say if this O-group capelin are de- rived from the spawning area off Sbuth Iceland or whether a minor spawning has taken place in East Greenland waters. Numberous O~group

capelin were observed west of Iceland suggesting that the 1970 year-class may be fairly abundanto The adult capelin schools recorded northwest of

Iceland will probably move east during late autQ~n.

Perhaps the most striking features of this survey, is the very low abun- dance and restricted distribution area of the O-group cod and haddock.

This may be caused by a very low survival rate for the 1970 broods of these species or the main part of their populations has reached the north coast of Iceland at this time of the yearo The possibility also exists

that the O-group cod and haddock have gone to the bottom already. I t should be noted that no adult or 07grouP herring were recorded in the area surveyed, indicating that -the abundance of herring of the Icelandic spring spawning stock must be low.

This year1s redfish brood is distributed over a wide area, thus indica- ting a strong one. However, this is the first survey of this kind in the Irminger Sea and final conclusions will therefore have to wait for the future.

Lengr~ frequencies of the different species are listed in Table 1 and illustrated in Figs. 18 and 19.

REFERENCES

Brainbridge and Colett 1968. The Zooplankton of the NORWESTLANT Surveys.

Spec.Publs intoColnmn m~.Atlant.Fish NO.7~101-122.

Dragesund;O., Midttun,L. and Olsen,S. 1970. Methods for estimating distri- bution and abundance of O-group fish. Coop.ResoRepoSer. A

int.Coun.Explor.Sea,18: 25-34.

Table 1. Length og O-group fishes given by trawl s'bations. Length in mm S t .no. 40 4 5:" 6 7 8 9 50 123456789 60 1 2 3

4

5 6 7 8 9 70 1 2 J 4 5 678 9 80 1 23 L~ 5 'Co'd A VII 1 1 A VIII J A XI 2 2 1 G XVI 1 1 Haddock A V 1 A VII 1, 1 1 1 1 1 1 2 1 2 1 1 2 A VIII 1 1 1 A XI 1 1 1 1 1 G XIII 1 Blue whiting G II 1 G III 1 G IX 1 G ZIII 1 Blue ling A II 1 1 A III 1 1 A V 1 A IX 1 G I 2 1 G III 1 Catfish A VII 1 A IX 1 A X 1 G XII 1 G XIV 1 G XVI 1

68'

• HVDROGRAPHV

• < BATHY THERMOGRAPH

• PElAGIC TRAWl

67'J -ICE BORDER KOlBEINS Er

66'

" "

.

-~: of '~"'~;'-~~J~

65'

/'~ ~~ ~,

^.,

,r~

~_,_... ':---0---><______<<--..0_, I

>.----ox 79 _

t=='---'---lt--A-=lt 6/:

I'ORTlANJ

61-

s

44' 42' 40' 38' 36' 34' 32' 30' 28' 26' 24' 22' 20' IS'

Fig. 1. Survey routes and grid of stations 1-11 August 1970.

68'

67'

66'

65'

64'

61-

s!-

61'

LI/

ECHO RECORDINGS 1-11 AUG 1970

= VERY SCATTERED ..;.;;;;- SCATTERED

-I\IIft- DENSE

-lOO<- VERY ^< DENSE

-' ..

'~....

^{. w}

.. ~ m"'::?

~HHJ[" ^... "H ..

/

^...

.. :: ... ::::::.,.

... ~.

--.~-.-:-:-:-~:;-"

~ f.O' 38' 36' 34' 32' 30' 28' 26' 24'

Fig. 20 Total echo abundance along the courses.

22' 20' 18'

6(.

t'e 6M

,·n

AlJG 1970

d~''i>

if'

81-

'"vi

^,.JIJ

fIJ'

65'

61:

6~

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1_----~--.-t ff.l~

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. ; l

,I.' _{'2' 1.0' 3" 36' 3t.' 32' 30' 28'}

Fig. 3. Isotherms at 6 metres depth.

68" ..

"C' 5010f 1-11 AUG. 1970 8'"f

e(..

65~

$/,'

sf-

41.' J.2.' 40' 311' 36' ^3/,' 32' 30' 28'

Fig. 4. Isotherms at 50 metres depth.

.f VI

26'

26'

I

\

2/

24'

21.' 20' 18'

22' 20' 18'

68"

61'

66'

65'

64'

63"~

6t~

1,1:

Fig.

68'

61'

66~

55'

64'

5t-

6

44'

I'C lOOM 1-11 AUG 1970

7~

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1,/4 1,0" 38" 36' 34' 32' 30' 28' 26"

5. Isotherms at 100 metres depth.

~"

tOC 200M 1-11 AUG.1970

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4 56 5

40" 38' 36' 34'

10

32' 30' 2B' 26'

21.:

24'

Fig. 6. Isotherms at 200 metres depth.

,. -,--

22' 20' lB'

22' 20' lB'

bH'

67"·

6S'

65'

64'

63'

61'

44' 42'

S'/.. 6M 1-11 AUG 1970

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40' 38' 36' 34' 32' 30' 28'

,

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26' 24'

Fig. 7. Isohalines at 6 metres depth.

<S

22' 20' IS'

0101

100

200

300

400

000-

600

700

800

900

1000

ST. NO. 73

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STATION ALFA - CAPE TORDENSKiOLD

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3-4 AUG. 1970

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Fig. 8.

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STATION ALFA - CAPE TORDENSKIOLD

"G. O. SARS"

3-4 AUG. 1970

\

,

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Temperature and salinity in a section Ocean Weather Station Alfa - Cape Tordenskiold.

ST. NO. 92. ₉₇ 85 92 OM

100

lOOi 300

400

500

soo~

700 '

800

900-

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Fig. 9.

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^{t· ..!.. I I ----S}

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Temperature and salinity in a section Cape Dan - Southeast

217 ST NO 21\

~ \C ' ^_~-9~

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t· C LATRABJARG ARNI FRIDRIKSON

9 AUG 1970

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50

100

150

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Fig. 100 Temperature in a section Latrabjarg - West.

68'

67'·

44'

CAPEUN

A PELAGIC TRAWL

Q

^O-GROUp·

~Itll ADULT

42' 40' 38" 36' 34" 32' 30' 28' 26' 24' 22' 20' 18'

Fig. 11. Distribution of capelin. Filled symbols are stations with catch.

68'

6t,

66'

65'

64'

61-

6f..

61'~

.:::::J

1,/:·

11 PELAGIC TRAWL

® NORWAY POUT ij) BLUE WHITING

/~

/

,,6

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32' 30' 28'

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",\'"

t'

A

f!)

26' 6

"

@

6

"

24' 22' 20'

Fig. 12. Distribution of O-group blue whiting and Norway pout.

Filled symbols are stations with catch.

18'

68'

6f-

66'

65'

6l.'

61-

6f-

O-GROUP REDFISH

A PElAGIC TRAWL

/~

f

<f

I"~ /'

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j

30' . 28' 26' 24' 22' 70'

Fig. 13. Distribution of O-group redfish. Filled symbols are stations with catch.

68'

67'·

66'

65'

6l.'

6:f.

6f-

44'

l> PELAGIC TRAWL

~ O-GROUP COD

~ O-GROUP HADDOCK

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40' 38'

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36' 34'

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@I

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28'

A

~

~

~

A

26' 24' 22' 20'

Fig. 14. Distribution of O-group cod and haddock. Filled symbols are stations with catch.

IS'

18'

68'

6t,

66'

6S'

6/.'

sf

61-

61'

44'

6 PELAGIC TRAWL

~ O-GROUP CAT-FISH

~ O-GROUP BLUE LING

~'

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[!]

6

[!]

"

38' 36: 34' :l2' 30' 2e' 26'

6

{).

6

6

24' 22' 20'

Fig. 15. Distribution of O-group catfish and blue ling. Filled symbols are stations with catch.

68' O-GROUP GREENLAND HALIBUT

e:. PELAGIC TRAWL

6t,

66'

65'

6/.'

6f

,11 "

I,l.~ _ ... ..-\:30

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,

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"

• •

• •

A

/),

A

32' 30' 28' 26'

6

•

6

A

A

24' 22' 20'

18'

18'

Fig. 16. Distribution of O-group Greenland halibut. Filled symbols are stations with catch.

68'

67'-

ss'

65'

64'

6'!-

6f-

61'

44'

A PElAGIC TRAWL

• lUMPSUCKER

(iJ SAND EEl

,.,rI'"''''

... ...tJ'l'rfrrJ ·'·

"

",,,,, / " t / '

,,<IV

,i

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"

l :/

I

i

'i ~

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, ~. .l

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., ~\ "

j: ""

42'

"

40'

"

I

~

, ?

~

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" " "

~

"

"

38' 36" 34' 32' 30'

"'"

/ / " '

ti.';.t'

til

IiI

~

fXl

28' .~

26'

"

"

<IV

•

III

24' 22' 20'

Fig. 17. Distribution of O-group lumpsucker and symbols are stations with catch.

sand eel. Filled

Fig. 18.

40~ CAPELlI< Cl

f\,

^{N: 6S'}

20 ~ i : 52.0

5.6.10

40 ~ _CAPELIN AXI

1<:3/0

ror ,il;,

, ,

G XI

CAPELIIoi

w 40

1\ ",,53

Cl 20

;::;

z w u et::

l:e 40~ _C~PELIN AX

A

1/;'1)0 20 ~ X.'3.0 5.1.21

1

40r _CAPELIN G XVII

Na120

rot . ~.~.

^s.I.21

40 BLUE WHITING

t\

^{N~ 38}

201 x ^{= 70.3}

S= 6.4

40\ NORWAY POUT

N=45~

/ \ ^i.44,8

201 S= 6.5

20 40 60 80 100 120 140 MM LEN,GTH

Length distribution of capelin, blue whiting and Norway pout.

18'

40~

20

~

40 t

20

~

40~

~ 20~

f5! z

U w

0::

~ 40~

20

~

40 20

40 20

B I

r\

i I I I

B n

,J, "-

....

B III

_••

/ \

B IV

/ \

20

⁴⁰

⁶⁰

REDFISH N=338 X= 38.5

s=

^5.93

REDFISH N=805

x

^{= 40.1}

S= 5.23

REDFISH N= 513

X = 39.5 S= 3.63

REDFISH N=485 X=37.2 S= 4.90

GREENLAND HALIBUT N= 83

X = ^65.7

S= 6.70

SAND EEL N= 770

X = 71.0 S= 12.05

80 100 120 140

MM

LENGTH

Fig. 19. Length distribution of red fish, Greenland halibut and sand eel.