CM_1961_HerrSymp_42.pdf (335.5Kb)

International Council for the Exploration of the Sea

C .M. 1961 Herring Symposium

No. 42

The Norwegian Small and Fat' Herring Fishery, Changes in Size and Composition.

by

Olav Dragesund

The total catch of immature herring ( small and fat herring ) landed in Norway in the period 1900-1960 has varied considerable from year to yea]"

(Fig. 1). Nevertheless the amount of small herring has increased in this period, eEpecially from 1910 and onwards& In the period 1900-1910 the average catch per year was 0.218 mill. hI, whereas the average catches per year in the following two decades were 0.6;7 and 0.769 mill.hl., respectively (Table 1.).

The main reason for this increase in the landing figures was the development:

of the oil and fish meal industry, which took place during and afteF the first World War. In the next three decades ( 1930 - 1939, 1940 - 1949 and 1950 -1959) the average figure s landed per year amonted t'o 1 .. 379, 1 .. 334 and 1. 705 mill. hl., respectively.

The yield of the fat herring fishery, howeve~, has not show~~ the same increase as the small herring fishery. Excluding the period 1950-1959, when the average catch per yeaIl'was 0.737 mill.hl., the figures have changed between 0.312 - 518 mill*hl. in the other perio~s in question (Table

1.).

The main fishing districts for small herring have been Troms and Nordland - North-Tr0ndelae. BetweemJ 50' and 65

%

of all the small herring landed have been caught in these three counties in the last 50 years. (Fig.2.). Before the oil and meal factories were built up most of the small herring were.. lande~ in the southern part of Norway, where also the majority of the canning companies were..

situated. The landing figures in the first ten years period, is thus no indi- cation of the abundance of the herring present in this area.

The small herring fishery takes place mainly in two seasons, during the spring - early summer and during the autumn. Data of the distribution of the landings with time are available only for the last 20 years (Fig. 3). Judging from the figure there seem~ to be a greater distinction between the spring- early summer and the autumn season in the last ten years than in the previous period.

The small herring caught in May-June were mainly landed in southern Norway in 1951 - 1.960, whereas the majority of the herring caughir during the autumn were landed in the northerrrrno stc countie s (Fig .. 4).

The: minimum in February' - April is due to the fact thait; the fishermen are occupied on other fishing grounds, whilst the reason for the minimum in Augus1:t- Septemberr must be the scarcity of small herring inside the skerries at thaii time.

In O<Ytobe:rr - November, howeverr, the herring immi'grate into the fjords and be- cmme available for the fishing fleet.

The small herring landed in the autumn consist of the 0- and I-groups, the O-group predbminating. During the spring-early summer season these same yea]'- classes predominate in the catches but the herring are now one and two years old respe~tively. The II-group' gradually appears in the fat herring catches during the summer and later in the autumn a new year class (the O-group) also appears in the catches. Thus there' are three: different yea~-classes represented in t4e landings during the calendar year.

If howeverr, the year is divided from the 1.September - 31. August, the yield mainly consists of two year-classes. (Fig .. 5). Data for dividing the lan- dings according t.o yearclass are only available from 195'0 and onwards. The relatively big catches in 1950/51 are due to the O-group (195D-year class) whereas the 19~0 and 1951 year-classes yielded about the same in the following year.

- 2' -

In 1952/53 the O-group ( the 1952 year~class) again pr~dominatea the catches. This was also the case during all the following years, and in 1959/60 the 1959 year-class yielded more than 90

%

of the total landing of small herring. No corre:J.ation has been found between the yield of a year- class as O-group and the relative strengJt:b of the same year'-class in the mature stoc-k; howeverr, there seems to be a positive correlatioN' between the yield of the I-group, and the subse:quent relative strengt:b of a year-class as adults. (Fig.6).

When considering the fat: herring, the- South-Tr0ndelag-M0re region has been the most important fishing district during the last ten years, whereas Nord- land-North-Tr0ndelag and to some extent Troms have been the main fishing areas in former years (Fig.2).

In the northernmost districts the fat herring fishery mainly takes place' during the second part of the yeart whereas in Southern Norway most of the herring is landed during the spring (Fig~4). The herring landed in April-June is called "forfangstsild"; which is a mixture of first time spawners and fat herring.

Because of the wide spread in time and place- of the catches it is very difficult to obtain representative samples of the herring which are landed.

Nevertheless an attempt has been made to give the age composition of the fat herring landed in the different distric~s in the period from 1952-1959.(Fig.7).

The IIforfangstsild-" samples are taken as representative for the catches landed in Southern Norway (S0r-Tr0ndelag-Rogaland) during the firs~ part- of the year ( 1.January-30.June), whereas the fat herring samples taken in the rest of the year in this district will be taken as representative for the landings from 1.July-31. of December. In northern Norway most of the fat her- ring samples are takeIT in the second part of the year, when the majority of the herring are also caught. As will be seerr from the age composition? the strong 195'0 year-class has predominated in the cathces, followed by the 1:953 year-class.

Table 1. The yearly average catch of small and fat herring in mill. hI. landed in ten year periods from 1900-1959.

Period Small herring Fat herring

- - - - - - - - - - ^- - ^{- - - - - - -} - ^- - ^{- - -} - -

1900

-

^{1909 0.218 0.406}

1910

-

1919 0.637 0.462

1920

-

^{1929 0.769 0.462}

1930

-

^{1939 1.379 0.518}

1940

-

^{1949 1.334 0.372}

1950

-

^{1959 1.705 0.737}

-

I

X---J<.

..j._. - - . -+-

3

o

^{FAT HERRING,} TOTALCATCH.

I - " - ,PERCENT

. t ^{O:l, ,OrMIU. HL.}

o 20 50 PER CENT,

~~---~--,--~

L

"

.

TOTAL

SMALL HERRING FAT HERRING

TOTAL AVERAGE CATCH PER YEAR:

SMALL ti~Rfll!llLz!ZB!JiJ"

FA T H£.'lB!~ ___ ~Q:i549 Ht,

.. f

1-

I -x-·

t

\ lIlih

ⁱ

'.itA~i

~ •. ~ If" -(.L

,,~ ...

TOTAL AYERAGE CATClf PER YEAR,

~j,~(l_~~,

_faT _I:I.!;RRIIiG .4§~?!.llh

NlIib.!

,~-Y~

fl J!

--'--,_ r

TOTAL AVERAGE

--~ CATCH PER YEAR:

'.'U

~J,k_,!i;Jl!lJI'ISL1)34320HL-

fl,.:! .. _1iE~R.INY ____ .!l7224B HL,

'---1--

I

I

! _,

'.

--:l

--_.~~ ~hRr7: f{lf ~

.• I

TOTAL

AVERAGE~

CATCH PER V

~lUlfBEJOO 769.66 FAT HERRIN

TOTAL AVERAGE

ALL HERRING 17276!!l BL1:!;;R.RING _____ 7~

SMALL HERRING.

THOUSAND HL.

;:H-i ^m~11950

- - - - i - - t - - 100 - - - +--:~..cp---+--+-...

50

5001

450

::~+-+--t- -- ^-1---

300 1951::J.92Q

:50 .

^f

JA. FE. MA. AP. MA. JU. JU. ^}IV. SE. DC 00. DE.

.-TROMS.l

I

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10

°1

IBUHOLMSRASA - STAD

, ,

5°1

^f-.--.-.

^, ~ b

^,

1

001

STAD -ROGALAND ;

I

50-1 I

~ I l i ,

^I

I _{i i} ⁱ

I

JA. FE. MA.AP. MA. JU. JU. AU.SE. OC. NO. DE.

_':_'ro,,: 195'1 -- 1960.

THOUSAND H L.

250

FAT HERRING

I I

200 150 100

ru1:J.9.5Q..

50

30 25

j

1951-:-196CL:

2

o

Qt-i----t--_+__

150

l00---l----+-- 50

JA. FE. MA.AP. MA. JU. JU. AU. SE.OC. NO. DE.

THOUSAND HL.

';~l ^I

^I

^I

^FINNMARK

_I ^I

^I

~i

::j ^I

^I

^{t---. I l I}

^ITROMS!

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100

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rllONOjLAG

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^{_. r -- -}

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/<7>1 I~

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-r

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JA. FE. MA. AP.MA. JU. JU.AU_ SE.OC.NO. DE.

60

SO 40

JO 20 fO

- -

-- ^. -. f- ..

l'1ill.hI.

26'

2.7 2.6 2.5 24 2.3 2.2 2.{

2 19 18

{7

If la 0.9

o.ll

07

• - - . - + -

. f

__ n ^{t I}

n ^{n r} 1

r-

I

I

I

----+ --

,+ .. -

^.. ---.. -.---

_._--_._---

I lPeJO ^,,::.262$

l/lo/

n n .., ...

^~

-

3456' 7 8 910 11;2131416-fO 171819202(222324

comrosi tior, of'

"/.

70i

6(i~

5~

1952.

FfNNMARK-NTRONDELA.G

1

TOTAL CATCH :152525 HL

i

1tJ

% ^I 1953.

90-1 . I. I 1

80 tf.1 NN~AJ~f(-^N. TR6NDEl.~G~

70 ' , ! I

, I

El .. '~""~~"- J

20+ i

S, TRONDELAG-:Pc;JG:.LAln . 1/1-30/6.

1 . 1 . I I

. ~TRONDELAG-ROGALAND.

I

'-T1~~J~i6~"

'-','"

~

I .

TOT;""-CATCH: 20S813 HL •.

. I

% I 19;t;,5:::-4;--.~--'-"'--'I"--'-'-'---L--!---'---J··

! I I I .. I . I .

70 F1NNMA8..K-ri,LRi:iNDELt;~ S. TRONDELAG- ROGALAND.

6 I

I

I -f-' Yli3CV6'-I--r-1 - -

TOTAL CATO!: 7SSL,74 HL. TOTAL CATCH: 6711.07 Ht.

I

^{I .}

I

I I

t

% ..

8[F'NNMARK - N .TRONDELAG. 1955.

~O

TOTAL' CATC) 152021 ^HL

1-- .

50 r

1

40 .1- -

30j 20

10 J

% I, ^I. I . 195Ci.

1001FINNMARK-N.TRONDELA.~

90 ' I

I :

80 TOTAL CATCH. 127000 Hl

~~l I !

^I

~ ^{. '}

rttJ

1 2 3 "

S. TRONDELAG - ROGALAND..:...

: 1/1 13CV6. I I

, .... TOTAL CATCH: 100920 HL.

I

Fig.

7.

The aGe conrosition of i"" ~ 1 u,"l 0'. r'I '\ .; 1'-' ,': -'PI'" ,e. "''''1,.1·

.. ->.1.v_ <. t,,:; ... i J - . " l,. ... ...L...J... , ... L'I::. 1..11..1

ft IorlclIl[:;st sil<.~t!T

.' 1959 •