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International Council for CM 1978/H :33

the Exploration of the Sea Pelagic Fish Committee Ref : Demersal Fish and Hydrographic Committees

Preliminary report of the International O-group fish survey in the Barents Sea and adjacent waters in - August - September- 1978

INTRODUCTION

The aim of this survey has been to study the geographical distribution and the abundance of O-group fish in the area . Temperature observations has been made along the survey tracks in order to give a brief discrip-

tions of the temperature condition in the area, and the data gives some indications of changes from year to year in the main current system .

PARTICIPATION AND ARRANGEMENTS

A preliminary plan for the 1978 survey was discussed by correspondance . Coordination and final arrangements were discussed the 24 August in

Murmansk between scientists from the Polar Institute of Marine Fisheries and Oceanography, Murmansk and the Institute of Marine Research, Bergen .

The survey program was covered in the period 20 August - 10 September and the following research vessels participated in the fourteenth interna- tional O-group fish survey in the Barents Sea and the Svalbard region :

USSR "Fridtjof Nansen" 25 August - 8 September State Name of vessel

Norway "G .O .Sars" 25 August - 10 September Institute of Marine Research, Bergen Norway "Johan Hjort" 20 August - 10 September

I' "

USSR "Poisk" 25 August - 10 September The Polar Research Institute of Marine Fisheries and Oceano- graphy, Murmansk

- 2 -

Name of scientists and technicians who took part on the different vessels are given in Appendix .

Data collected during the survey was analysed during a meeting in Hammer- fest the 11 - 13 September between scientists from the two participating countir e s . Some preliminary findings are given in this report .

MATERIAL AND METHODS

The geographical distribution and the density of the O-group fish were estimated by fishing with small meshed midwater trawls in the scattering layer, mainly between 0 - 50 m . The trawls used by the different vessels

and the trawling procedure were the same as described in the 1977 report of this survey (Annls . Biol . 1977) .

Survey tracks and hydrographical stations worked are given in Fig . 1 . Trawl stations with and without catch are indicated on the species distri- bution charts (Figs . 10 - 18) .

RESULTS

Hydrography (Figs . 2 - 9)

Hydrographic observations were carried out along the survey tracks and several standard hydrographic sections were worked . Horisontal tempera- ture distributions are shown for 0, 50, 100 and 200 m depth in Figs . 2 - 5 . Average temperature in four of the standard hydrographic sections

(Figs . 6 - 9) are given in Tables 1 - 4 . The general comments are given :

1) Kola section

A Cooling of all layers was observed from 1976 to 1977 and a further decrease in temperature was recorded this year . The anomalies are - 0 .7 ° , - 1 .1 ° , - 1 .0 ° for the layers 0 - 50 m, 50 - 200 m and 0 - 200 m respectively .

2) Cape Kanin - North section 3

The mean temperature is the lowest observed for the period 1965 - 1978 . The anomalies for this section are even larger than for the Kola section, - 1 .9 ° in the south and - 1 .7 ° in the north .

3) North Cape - Bear Island section

The mean temperature in the 0 - 200 m layer are 5 .0 ° compared with 4 .8 ° in 1977 . The anomalie are - 0 .6 ° .

4) Bear Island - West section

The mean temperature in the 0 - 200 m layer are close to the average for the period 1966 - 1978, 4 .1 ° compared with 4 .2 ° .

Generally, the low temperature conditions in the south Barents Sea in 1978 indicate low water transport by the Murmansk current .

The temperature conditions west of Bear Island in 1978 indicate a more normal water transport in the Spitsbergen current .

DISTRIBUTION AND ABUNDANCE OF O-GROUP FISH

Distribution of O-group fish of the main species are shown by shaded

areas in Figs . 10 - 18 . Areas with double shading indicate dense consen- trations of O-group fish . The criteria used to discriminate between

scattered and dense consentrations in the distribution charts is for cod, haddock, redfish and Greenland halibut 85 O-group fish caught per haul, for capelin and polar cod 1050 and 110 respectively . Abundance indices are calculated as area of distribution, the areas with high densities are weighted by 10 . The abundance indices are given for the year classes 1965 - 1978 in Table 5 . Length distribuitons of main species are given in Fig . 19 .

Herring (Fig . 10)

0-group herring was distributed over a larger area than in previous years .

Catch per haul has also increased, indicating a slight increase in the offshore distribution of O-group herring .

Ma cker el (Fig . 11)

Mackeral has occationally been recorded in the O-group survey . This year the mackerel was observed in a wide area from Lofoten to North

Cape .

Capelin (Fig . 12)

O-group capelin was distributed in the central part of the Barents Sea . The distribution area was small and the estimated abundance index is the lowest recorded in the period 1966 - 1978 . There is, however, a rather low correlation between the 0-grqup indices and the acoustic

abundance estimate of the year class as two year olds . In spite of this, the survey indicate that the 1978 year class is poor .

Cod (Fig . 13)

As in 1977, the O-group cod was distributed in the central Barents Sea and along the Bear Island - West Spitsbergen shelf . The O-group cod was not distributed as far east as in 1977, and no dence consentration was observed in the central Barents Sea . Dense consentrations were observed along West-Spitsbergen, indicating higher abundance of cod in this area than in the most recent years . The abundance index indicates that the 1978 year class is below average .

Haddock (Fig . 14)

O-group haddock was not observed as far east in the Barents Sea and as far north off West-Spitsbergen as in 1977 . The abundance index indicates that the 1978 year class is below the average year class strength, and

only half of the 1977 year class which was an abundant one . 4

Polarcod (Fig . 15)

As in previous years, O-group polar cod occured in two components, one in the Spitsbergen, and one in the Novaya Zemlja area . Neither the 1977 nor the 1978 survey covered the whole area of distribution . Estimated abundance indices are therefore too low . However, compared with the

1977 data the 1978 observations indicate a somewhat lower abundance of the Spitsbergen component and a somewhat higher abundance of the Novaya Zemlja component .

Redfish (Fig . 16)

O-group redfish was not observed as far north off West-Spitsbergen as last year, but the area of dense consentrations was similar to that of 1977 . The abundance index indicates that the 1978 year class is strong .

Greenland halibut (Fig . 17)

Greenland halibut was only observed in the West-Spitsbergen area as in previous years . Compared with 1977, the fish was distributed further to the west . The abundance index was the highest estimated in the period 1970 - 1978 .

Long rough dab (Fig . 18)

O-group long rough dab was separated in two components . The Bear Island/Spitsbergen component had a similar distribution as in 1977, while the Barents Sea component was distributed over a wider area in the sentral part of the Barents Sea . The abundance index indicates that the 1978 year class is above average abundance .

- 5 -

Table 1 . Year Layer 0-50 m 50-200 m 0-200 m

Mean water temperature in the Murmansk current, the Kola section (between 70 ° 30'N and 72 ° 30'N) at the end of August (t ° C) . 1965 6 .7 3 .8 4 .6

1966 6 .7 2 .6 3 .6

1967 7 .5 4 .0 4 .9

1968 6 .4 3 . 7 4 .4

1969 6 .7 3 .1 4 .0

1970 7 .8 3 .6 4 .7

1971 7 .1 3 .2 4 .2

1972 8 .7 4 .0 5 .2

1973 7 .7 4 .5 5 .5

1974 8 .1 3 .9 4 .9

1975 7 .0 4 .6 5 .2

1976 8 .1 4 .0 5 .0

1977 6 .9 3 .4 4 .3

1978 6 .6 2 .5 3 .6

Average 1965 - 1978 7 .3 3 .6 4 .6 Table 2 . Mean water temperature in the Cape Kanin - North section (between 68 ° 45'N and 72 ° 00'N) from Year

surface to bottom at the beginning of September (t ° C) . 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 Average 1965 - 1978 68 ° 45'N 4 .8 2 .0 6 .1 4 .7 2 .6 4 .0 4 .0 5 .1 5 .7 4 .6 5 .6 4 .9 4 .1 2 .4 4 .3 70 ° 05'N 71 ° 00'N 4 .2 2 .5 3 .6 3 .1 2 .3 3 .3 3 .2 4 .1 4 .5 4 .3 4 .6 3 .3 1 .7 3 .4 72 ° 00'N Table 3 . Mean water temperature in the North Cape current, the North Cape to Bear Island section (between Year

71 ° 33'N, 25 ° 02'E and 73 ° 35'N, 20 ° 46'E) at the beginning of September (t ° C) . 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 Average 1965 - 1978 Layer 0-200 m 5 .1 5 .5 5 .6 5 .4 6 .0 6 .1 5 .7 6 .3 5 .9 6 .1 5 .7 5 .7 4 .8 5 .0 5 .6

Species Yea Capelin Cod Haddock Polar cod West East Redfish Greenland Halibut Long rough dab 1965 37 6 7 0 159 66 1966 119 1 (1 129 236 97 1967 89 34 42 165 44 73 1968 99 25 8 60 21 17 1969 109 93 82 208 295 26 1970 51 606 115 197 247 (1 12 1971 151 157 73 181 172 <1 81 1972 275 140 46 140 177 8 .0 65 1973 125 684 54 (26) 385 3 .2 67 1974 359 51 147 227 468 13 .4 83 1975 320 343 170 75 315 21 .1 113 1976 281 43 112 131 447 15 .6 96 1977 194 173 116 157 70 472 9 .0 72 1978 40 106 61 107 144 460 35 .4 76

Table 4 . Year Layer 0-200 m

Mean water temperature in the West Spitsbergen current along the West Bear Island section (between 06 ° 34'E and 15 ° 55'E) in early September (t ° C) . 1966 3 .3

1967 4 .2

1968 3 .6

1969 4 .2

1970 1971 4 .2

1972 3 .9

1973 5 .0

1974 4 .6

1975 4 .9

1976 5 .0

1977 4 .0

1978 4 .1

Average 1966 - 1978 4 .2 Table 5 . Abundance indices .

80_

790

Q I

X/

to ¹⁴¹

P

8

20 AUG . -10 SEP 1978 z CTD SONDE STATION x HYDROGRAPHIC STATION

40° 45° 50°

z

Fig . 1 . Survey tracks of the ships and the grid of hydrographic stations .

9

Fig . 2 . Isotherms at 0 rn .

Fig . 3 . Isotherms at 50 m .

Fig . 4 . Isotherms at 100 m .

F _g . 5 . Isotherms at 0C M .

- 12 -

13 -

Fig . 6 . Temperature section along the Kola meridian .

Fig . 7 . Temperature section Cape Kanin - North .

LAT. N 76°00' LONG .E 33 °30'

LAIN 69°30' LONG .E 33°30'

- 14 -

Fig . 8 . Temperature section Bear Island - North Cape .

Fig, 9 . Temperature section Bear Island - West .

5° 10° 15°

81°

_5' .

7'

G G

G

J

G

G ®G G!S J

20°

G G G

G

25° 30°

1

G

G

Fig . 1 0 . Distribution of 0-group herring . G f

a 35°

20 AUG . -10SEP. 1978 o PELAGIC TRAWL STATION

o BOTTOM TRAWL STATION 0-GROUP HERRING

G

40° 45°

G 50 °

G

10° 15°

-

16 -

Fig . 1 1 . Distribution of 0-group mackerel .

35°

20 AU G . -10 SEP 1978 0 PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

0- GROUP MACKEREL 40° 45 ° 50 °

0

D 0 A G p

A

Fig . 1 2 . Distribution of 0-group capelin .

20 AUG . -10SEP. 1978 o PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

0-GROUP CAPELIN

Fig . 13 . Distribution of 0-group cod .

20 AUG . -10 SEP. 1978 PELAGIC TRAWL STATION n BOTTOM TRAWL STATION

0 - GROUP COD

- 19 -

n

nQ

n n

C,

1 A

A A

n n

n C,

n non n o n o n

n n n

A

/~~n

0

n A.

a

6

P

n n

1

4

20 AUG . -10 SEP. 1978 n PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

0-GROUP HADDOCK

A A A A A n

• m o o n

•

n o n o

•

•

n n n n n

Ap n A 0 n

A

n

A

• 0

Fig . 14 . Distribution of 0-group haddock .

- 20 -

15° 20° 25° 30° 35° 40 ° 45 ° 50 °

Fig . 15 ° Distribution of 0-group polar cod,

20 AUG . -10 SEP. 1978 c PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

O -GROUP POLAR COD

Fig . 16 . Distribution of 0-group redfish .

20 AUG . -10 SEP. 1978 o PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

O -GROUP REDFISH

*r

mr

or

- 22 -

~ 20 AVG . -1OSEP 1970

* PELAGIC TRAWL STATION o BOTTOM TRAWL STATION

O-GROUP GREENLAND HALIBUT !

Fig . 17 . Distribution of 0--group Greenland halibut .

u

A

so"

5- 10* 15° 20°

2 3

25° 30° 35° 40°

Fig . 18 . Distribution of 0-group long rough dab .

45° 50 °

20 AUG . -10 SEP 1978 PELAGIC TRAWL STATION o BOTTOM TRAWL STATION 0-GROUP LONG ROUGH DAB

J

I z

w

U a-

I ix w m z

30 20 10

40 30 20

10

10

30 20 10

20 10

30 20 10

40 30 20 10

30 20 10

2 10

30 20 10

30 20 10

20

I

40 60 00

L.ENGHT ----

MM

100

Fig . 19 . Length distribution of 0-group fish .

120 I 140

RRING 696

PELT N 13388

CKEREL 468

D 11818

DDOCK 2956

ITHE 127

LAR COD WEST 114907

LAR COD EAST 12279

DFI SH 300110

NG ROUGH DAB 680

EENLAND LI BU T

2191

_ 24 -

HE N :

,

I

U N :

I

MA N=

r I r r r r

'I '

r e , f

CO N=

HA N=

SA N=

e I e , ,

I

,

I

PC N :

T-

I

e i e e ,

I

I

, , e t

PC N=

I 1 ~ ' i

I

'

e e c e

I 1 I I

I 1 e 1

RE N=

e e r e r , , ^r

i

I I I

e i e r

LC N :

GR

HA

N=

APPENDIX Survey period Research vessel Research Institute Participants 25 August - 10 September "G . O . Sars" Institute of Marine Research, O . Annaniassen, T . Antonsen, Bergen . J . Hamre, K . Hansen, V . Helgason, A . Hylen, H . Kismul, E . Lifjell, O . Martinsen, A . I . Proven, A . Romslo, E . Saelen, A . Thomassen . 20 August - 10 September ''Johan Hjort" Institute of Marine Research, J . Blindheim, L . Kolbeinshavn, Bergen . S . Lygren, T . Monstad, J .E . Nygaard,

.

Tangen,

Torgersen, A . Asenjo .

August 10 September Poisk'I Polar Research Institute of A . S . Galkin, Z . M . Berdichevski, Marine Fisheries and Oceano- I . I . Balabanov, V . ja . Korelski, graphy, Murmansk . V . I . Zubov, A . P . Tereschenko, A . V . Averchenko, T . M . Sergeeva, A . V . Il'ina . 25 August - 8 September "Fridtjof Nansen" Polar Research Institute of S . V . Rochitelev, V . F . Terzlev . Marine Fisheries and Oceano- graphy, Murmansk .