CM_1964_141.pdf (508.7Kb)

This paper not to be cited without prior reference to the author Inj;'erna ti'onal Council for the

Exploration of the Sea

...£.H. 1964

Herring Committee No.

141

~~::.~ ~r >":::i""~";;,j~:L;~( /' Growth and maturat:i:on o-f the Norweg:l::'a:i1 ^{J ,}

herring

by

Ole J. 0stvedt

During the years

1958 - 196I

the recruitmen± to the mature stock

<rf the Norwegian spring spawning herring was at a very low level with

tae result that the average age and length increased (0stvedt

1963).

A similar period with low recruitment was observed during the years

19r2 - 1915

(Lea

1917)

when the year-class

1904

dominated. But alth- augfi thB average age in

1916

was exactly the same as in

1960, 9,8

Y;Bars, the correspolrcH ng- mean - length was only

32,0

cm against

34,1

cm in

196'0 •.

Thi-s difference in mean length could therefore suggest an

increase1~rowth

of the Norwegian herring as observed in the herring stocks 'Of the North Sea (Cushing & Burd

1957, 1962;

Parrish and CJ.'''-1g11

1963),

o-f the Skagerak (Anders~()n 19-~Jd. ~T',-'l ^{_L" n,C'} p'~'1 ^{L . ! --} ~T'-nn-f.c,l

1958) •

Figure 1 shows the percentage lengi±h compositions (cm below+) of aTl samples, :frrespccti ve of gears, secured during the winter hB-...r7j.~

seasons of

1907

to

1963.

In, this report distinction has nO.t been:. made.

1:iet'ween, "Targe herring" and tlspr.L1l.g hBrrillgll, whereas the reports on lengtth and age compos:i tii on, 01- Norwegian herring of Lea

(1929),

Runn;,...

st'r0IIl

(1936, 194I)

and Sund

(1943),

often refer to "spring herring"

mrly-or separatelT. I t is seen that the proportion of herring larger than-,

35 -....

^{-e-m~ j l l t -tvL,n 1 1} f'llgth has steadily increased during these years,

p~:!-A.;E .. nT:'l-r1:y in- the fift:fes when the rich year-class of

1950

predomi- nated._ The mean length of five, seven and ten year old fish during the

same period are shown in Figure 2. Fish in all stages of maturity o:btain-ed in the samples from the winter herring catches are included.

Maturity stages I, II and III were usually represented in small numoers in the youngest age groups only~ The ten year old fish were aTl mature (stage IV to VII during the winter herring fisherT). For the years

1941

to

1963

the mean length is given for gill net and purse

sein~ samples separataly. The difference in length of the five and seven year olds between purse seine and gill net samples js probably maDTly-due. to mesh selection by g:fll nets. For the ten year old fish the difference in length observed sometimes may be mostlT ascribed to the effects of various other factors, such as depth of fishing, shoa- lihg and fish behaviour. The samples from the winter fishery have in most years mainly been, drawn from the purse seine or land seine cat-

ches.

Since the beginning of this century the mean length for age

(Fig. 2) shows on the whole a trend of increase. The grand average of the mean length of five to fiften year old fish during different

per±cxds are given in Tab.ille 1. Apparently the length increase in. all the age groups was greatest during the last peniod, from

1951

to

1963

According tG Burd

(1962)

Lhe increase in~mean length for age in the herring of the southern North Sea was followed by an, earlier +No correctionB are made for the years

1930 (?)

to

1962

when,the herrihg were measured to the nearest

t

cm.

maturatrom and he concluded that the recruitment (maturation~ is a funGt±on; CYf le:qg-th and not age. Already Lea (1929 ) demonstrated the relationship bet1.ve.en length and maturation, and he, showed that the fast growing he:vring in the Norwegian. spring spmvning stock, termed southern type, reach maturity' earlier than- the slow growing herring of northern type. Runnstr0m (1936) distinguished between. several compo- nenXs within the southern,ann norther~ types according to the appea-

ran~e of the winter rings and summer zones. The winter rings were named~

according to Leas definitions; coastal, oceanic and spawning rings~

Runrustr0ID' showed that the first spawning generally- occurred ,..,-hen, the nerring had reached a length of aoout 28-29 cm (figures estimated from backcalculati'CJn of scale measurements)" This length would be reached at an< age ranging froID' 3 to 7 years; occasionally as much as 8 to 9 years. The conclusion to be drawn on from this is that the age at first mafur.i:tyr in herring IS closely related to the growth of the fish~

Consequently, i t should be expected that the observed increase :Ln mear_

length for age were accompanied with a corresponding decrease in age at first maturity- as suggested by Burd (1962) for

the

he:L"T~ng of the southern North Sea ..

In the previous report (0stvedt 15158) i t was shown, that the mean age at first spawning for herring of the southern type remained nearly constant at about 4,4 years for the year-classes 193L~ to 1944. The nurthern" type of the same year-classes showed on the other hand a decrease in their mean age at first spawning from 7,5 years for the year-class 1934 to 5,1 years for the year-class 1944. The mean age at first spawning for the northern type later increased again, beeing T,l year for the year-class 1950. This observed change in mean age at first spawning is probably due to variation in the relative abundance CYf different growth components within: the southern, and the northern, types of the year-classes. Im the year-class 1950 a slow growing type

(N

6_ ;

^{i . e .} six coastal and one oceanic rings) maturing at an. age of

ergilt years was especially abundant. I t is therefore of importance

when~

studying the possible effect of this length increase on maturity to consi'der separately the data of each growth type in the various year- classes.

Table 2 shown the length at different ages of a few growth types In some year-classes. Backcalculation from scale measurements of the length - age values were carried out for sevem to ten year O'ld fish.

I t is evj,dent· tliat the increase in length has occurred within, all the different growth types considered, bu± there is no indication of an increase in age at first maturity. Fish of the year-class 1950, matur- i~ at am age of four years (~ ) had at first maturity a mean length of 30,4 crrr while the mean lengtB. at first maturity' for the same growth type of the year-class 1904 was on~y 26,9 cm.

During the years 1946 to 1962 the mean length of all the first time spawners varied between 30,0 cm to 32,3 cm with a grand average mf 30',9 cm'. In~ the early thirties the mean length of first time spa- wners was generally- 28 - 29 cm (Runnstr0m. 1936). It is thus obvious

that tne length at first spm·ming has increased simultaneously- with the observed increase in length for age.

The fluctuation. in length at first spawning within the year-class 195() is shown in' Figure 3~ The length at first spawning range from 26' cm to more than' 34 cm; and fish maturing late were generally larger at first spawning than these maturing earlier. This appears also from tile data given by Runnstr0m (1936).

Beverton (1963) estimated the parameter IJ~ of the von Bertalanffy growth equation for the Atlanto-Scandian herring to be 35-37 cm when usfug the data of Sund (1943) and Runnstr0m (1936)0 The presen.t data for tlie year-class 1950 gives an L ~ of about 38-39 cm. I t should also be noted that the average length of the older age groups, mainly' the ye&r

class1950, in' the samples from the 1964 winter herring fishery was 36,3 cm .. Herring samples of old Norwegian herring obtained north of Iceland in June 1964 had a mean length of 37,5 cm. Beverton (1963) has furthelXlr sliowrr. that the ratio L /L ^oC' for Clupea harengus is rather

constaniJ at about 0,80 (L ,= J e¥tgth at fi-;st maturity). Iru accordan.ce witk this an~ increase in.

f'd'"

should result in a higher mean length

- 3 -

at first maturity, as shown_ by the present data.

The L distribution of the dlfferent growth types, given in Table

3,

shows

t~at

there is a trend towards higher values, and most of the

in~rease in length for age is main~y ascribed to higher values of L I • This is of particular interest in view of the changes in spawning tlme and place CID the Norwegian west coast spawning grounds in recent years.

The dart1:a given above show that the length far age may- increase

witltout any-detectable effect on~the age <mtfirst spawning. This in- fers that maturation is not simply-a function of growth. Burd

(1962)

found that' there is a minimaI length a herring must reach before the gORac's connnence to ripen~. This may be true, but as pointed out by Blaxter and Holliday

(1963)

the contrale of the process of maturatioll_

may-ne due to the interaction of some essential factors, such as food supply, temperature etc. Little is known about the duration: or the varIOUS maturi-ty stages of first time spawners. PreIiminary investiga-

tion on, the small and fat herring on the Norwegian coast seem to indi- cate considerably variation and this would also probably be refle.ted in lengtn and age at first spawning.

~ causes of changes in growth of herring have beelL discussed by several authors and some factors such as food supply- (Cushing and ffard

1957,

CushIng

1962),

temperature (Popiel

1958)

and stock density

(Andersson

1954)

have been considered. Since the increase in length for age of herring has been, noticed both in the Norwegian Sea and the North Sea as well as adjacent areas, i t is therefore of importance to investigate. which common: factors may controll the growth in,length of herring living iIT these waters.

.Am:ierssorn, K. A., 195?/- .. Studies on the fluctuations iTh the rate of growth of th e herring in the Kattegat and the Skagerak. Rep. Inst. Re$. Lyseki~, Se~. Biul.,

3 .:

I-I).

Beverton-, R" J .~ .. 196).

Braxt' er , J. H. S. and

Cusli±"ng, D. H., 196?

MaturatioI;l, growth and mortality of Clupeid and Engraulid stocks in relatiom to fishing.

Rapp. Corr~. Explor. Me~., 154 : 44-67.

HoIliday-,

If. q.. ^':f

^~, 1.9 6 ). The behaviour and

physiology of herring and other clupeids. In:

Advances in marine biology, ~, edit. by P.S.

Russe1 Academic Press. New York and Londalli

1963. .

Recruitme~t to the North Sea herring stocks, II. Fish. Invest. London, Ser. 2, 23(5) : 43 - 71.

n I!

"

and Burd, A"

9.,

^{1957. OIT'.} the herring of the Southern

North Sea. Ibi<;l!, 20(11) : ·1-31.

Bhrd, A., Lea .

,

^~,

,

"

¹¹

C,- , 1962.

191

7.

19 2

9.

Growth and recruitment in the herring of the Souther~North Sea, I. Ibid. 23(5) : 1-4?

Sildeunders0kelsen 1916 - 1917. Aarsberetn- Norg. Fis~., 1917 (1);: 39-47:

The herring scale as a certificate of origin.

Its applicability to race investigation9. Ra~p.

Cons. Explor. Me~!, 54: 21-3~.

Parrrsli, B. ~., and Craig, R. E., 1963. The herring of the north- western North Se~. Post-war changes in the stock fished by Scottish drifterse Ibid, 154 : 139-164.

Pop±:eI' , .J., 19 5~.

-' " "

Sum:l, Q!", 194) .•

0stvedt, Q~ Jp, 195~.

It " 11

The growth-rate of·the Southern. Baltic herring. ICES, Herring Commlittee, d09. nq.

48. .

A study of the life history and migration of the Norwegian. spring herring based on the analysis of the winter rings and summer zones of the scales. Rep. Norw. Fish. Inves~., 5(2):

l-lOJ.

Racial analysis of the herring inlNorwegian, waters. Ibid., 6(7) ,: l-llq.

The size of the Norwegian spawn herring. AUTI4 bio~~, 1 : 45-49.

Some considerat.ion concerning the homogeneity- of the Atlanto-Scandian herring. Rapp. Con?, Explo~. Mer., 1 4 3(2).:

53-51'.

Catch, effort and composition of the Nor- wegian winter herring fishery. Ibid., 154 109-117.

Tahle 1 YeaJrs

1908 - 1920 1921 - 1930 1931- 1940 1941 - 1950 1951 - 1963

Mean length in cm of each age groups of Norwegian herring in d.ifferent pel":L..ods Age 5

I

6

;--is

SI

I l~~r~-~:-I-~~I-;-~ I

l'S 15

-+---\- --\---+

--+1 ---

30,1 29,5

30

,81

31,5

- 3

1

,7

3

1

,9 29,8 30,9 31,8 32,6

30,~

31,1 32,0 3 2

,8

31,3\ 32,6 33,3 34,0

32,4 132,7'

I

33,5 33,2 33,2 34,5

33,6 33,6 34,9

33,1 33,9 .34,0 35,3

33,5 34,2 34,2 35,6

34 2

1

34,4 34,7 35,8

34,3 34,5 35,0 35,9

34,9

3/1-,7

35,1 36,0

\- 1919)

Table 2 Length for age of" di,fferent growth type s of the Norwegian' herring

s

2 + 1 I S 2 + 2 I1 N 3 + 1 N 3 + 2

I

N 4 + 2

-4 ----

I---~----" If . Year-class

I

--Year--olass

I!

Year-class

·1

Year-class 11 Year-olass

11

12

13

~

]5

16 j ]'77

I ,. I

IS : 19 : I ~O'

1904 S,S 16;9

23,4

26,9 28,6 29,S' 30;S 31 ,5

" 32,3

32~S Af!;e at fir sit. spavlrining " No i

57:

101: 55 S 2 + 1 N, 3 + 1

25

24 Sowtl1errn type, 2 coastal + 1 oceamLC' winter riR'g's Northern' type, 3 coastal + 1 oceanic winter rings

Ta1:l'le 3 11 distributi.orn of' diff:f:1'erenil growth types o:f' Norwegian hfl]Ti >")'0"

C !

cm below) Growth type --~.~.-.----~~---~--'--~

,-

I---;---.::..::..---n---~--- 11 S 2 + 1 11 S 2 + 2 N 3 + 1 N 3 + 2 N 4 + 2 cm YeaF.-crlass 11 Year-class Year-class Year-class Year-class 1950~19041

1923!1950 1904 ~923 i 1925' 1944 194r

1

1950 ' 1904 1918! 192" 19 25! 1~50 119°11918' 1192 31 1925~~44194r:~50f;f~~119 2 3119 ~__ ~

13 12' 11

10

9 8 7i 6 1 2

2 5 6 6 3 112 1 1

I

9

10 10

6

19 19 9 8 T

4 4

1 2 1 1

3 2 2 3 6 6

10

T

4

9 1 1

3 3 1 2 4 6 2 1 2 1

~ot-a~

\577,\101 \ 5,5\ 25 earn 1,8.8, 9.3 9.71 9,6

1 1

4

3 6 2 4 1 1

2 1 4 3 ! 6

I

5 3 4

I !I

I

'1 ! I 1

I

2

I

2 5 21 24 26 19 11 4 3

3 2 1

4

3 11

1 2 2 3 11 6

2 5 6

10

7( 4

11

~

13

2 111' I 17r' 18'

114-

23! :3 I 14

I 10 \

5 2

I

1 1

i 1 iI 2 7' 3

I

6

I

,

•

7(

I

2

~

1

I

I

~ 7'

10

1 16 1 16

1 15 7 10 8 5

9 2 3

2 1

1 1 4 6 8 8 6 5 2 3

1 1 5 6

: I

I 5 1 1 3 1

4 2 3 11

4

4 1 2 1

2 2 I .1

I 3,

j I

5

2 3 2 2

1 3 6 2 4 5 4

4

1

851 441

31 1

32 23/ 30

(' ~,8

,3

1 0

,4.

8 ,

9

9 , 2

I

9 ~ 6

4 6

15

12

15

9 9

1 1 1 4

4

3 4 2 3

721

23

7,5

9,- 3 2 3

1 6

9 13

17 5 18 6 8

10

8 8 2 1

6 19 9

4

2 56

11 02 I

1 ~ ') 63 I I

8,6 9,8 i9,4~7,0

1

1 2 4 I 2 4 I 5 4 12 6 15

4 15

6 I 12 5 I 8 1 1 36/ 1'4 8,0

8,5

I

~

^{I 1909}

^{90' .11\ '}

^{/ - -}

^{rc:~ ______}

^{' \ . '}

^{J J}

^{1927 1928}

^JY

^{, :}

^{' /\'}

^I

^{'I\~ I" ~- 1 1"'45 I ~ ~ 3 1(\}

^{1 1 I}

^/~I

J

¹⁹¹⁰

I \ ~ ^I ~ ~

^l1947

^! j \ "'-- ^I

~ j\1r\~ j~ JllC~~ _{I .J \'\.}

_{j 1930 /---'}

_{~, ~}

_{\ - .}

^I _I

1

1 1912

f'I \~ ^{j .----=! \}

^191.9

^I

_ J! \"'-

¹⁹³¹

^{0 "--} ~ ^I

i

1913 ---"";

,~~ ^{.J f\ \}

^{1950 / ' - I}

'I

^{. , L '} 1 / \

^j1932

^{/ '}

^{/ ' \}

~ ^-/\

^\

^I

~

^{"11 1914}

^{Ill\ I j 1/\\}

^,'951

J ",,\""-

_ _ .-J \ "'-- i

^{1933 I \ - --}

I.---/' \ ^I

ll1

_~ ¹

I 1915

⁾ I \ ^\

^{I' ===",}

J -.I \ " '

^{r I \}

~

¹⁹⁵²

~r\~ ' ,

«

i L . /I . ¹

^{1934 / \}

j...-< I~ ^I

~ ⁱ

¹⁹¹⁶

^{J \ 1, I} ~ ^____

^{---j \ 1953 j}

\~

~ ⁱ _~/ ^/''\ ~ ⁱ

^{"'35 /'-.} / , \ ' "

1 -~ ^\

^!

z _{_ I}

~

¹⁹¹⁷

_~~

^{/ \'\}

_j ^I

₁₉₃₆

~.../J ^\

_'--

ⁱ

_I ¹⁹⁹⁴

_~

^{/ '} _\

~ _i

I /~ ^{'- /'--}

^{r - \ t 1'--- ' -}

j 1918

_./

_/

r-I \

_\

_{\ 1}

1 ₁₁₉₃₇

~ ~

^{-J \} _'-

^J I~

^{1 19" / \}

^\

' - / " - - . ^r--

19'9

I~

^{, _}

~/

^\

^J

¹⁵⁰⁶

r,--~

/ \ ' " 1 / \

_--==~___ ~ _{! \'}

^{/ ' \} I

^1\\\

^\ '--

¹ ~ I

I ^{1938 i939}

~ ~'-, /~ ^{\ 1} j

^{I: 1957} 1958

~_.../~ ~ ~ ~ ;7\d

^"

^I

/ ' j ' ^{I / '}

_~ ^{f\- '-- \ j} 1""" ^~ 7'\ - ^\

^j

ⁱ

¹⁹⁵⁹

^..../ --r~

^/

;,,-:--0 '

~~!\J~ "1""~ ^{"-= I J 1\ ",,-I}

i

^{1923 \}

I ~ ~ ~ ⁱ

¹⁹⁶⁽⁾

⁾¹ k~

~/ ^V\

¹¹⁹⁴²

~/'\- ^{i _(1\}

^I

j

1924

J! \. ' i _ ~ ^{\" 1}

¹⁹⁶¹

^! !\~

_..

~f~ ^J

^{,943 I}

^.-1/'\\

^t

i

^{1925 '}

^\\J; 1---~~ ^J

1 9 6 2 ; . ---I '

\4

I , • , 1 9 4 4 "

I , / hI

^I

rf'.l

~.

2L ^I 26 28 30 ' 3'2 ' " ^{I , ,}

34 ~

i , , , 36 3S ! i 24 , i ---;:---' ' ,

J , . . . / I

¹⁹⁶³

III \

I ^\ ' 26 28 30 32 1 j, 36 38 . 2' .. 26 28 30 32 ' 34 36 38 ^I

~ ^lS()7

Fig. 1

,

... ength d" l.stribl ""

herr'in _ g

r .

" .1tlon of s~mple5

1stlery 1907 - 1963.

f'rom the

ALL GEAR<::'

PURSE SE1NE

GilL NET ^I

F if~' 2 f>le2TI 1"" ~~ng"h ... _ Of _ :f' lve

the Norwegian winter •

seven And . ten ye3r old :fish in

her-rinD' b f ' ::tslery. 1

---

35 36 cm

Fig.

J

Length distribution of :first time spawners of' the year-class 1950.