No. 4918

CANADIAN TRANSLATION OF FISHERIES AND AQUATIC SCIENCES

Investigations of metabolism in the Baltic cod during sexual maturation and spawning

by I.F. Vel'tishcheva, and G.N. Tokareva

Original Title: Issledovaniya obmena veshchestv Baltyskoi treski v period

polovogo sozrevaniya i neresta

From: Tr. Vses. Nauchno-Issled. Inst. Morsk. Rybn. Khoz. Okeanogr.

120: 51-63, 1978

Translated by the Translation Bureau Multilingual Services Division

Department of the Secretary of State of Canada

Department of Fisheries and Oceans Northwest Atlantic Fisheries Centre

St. John's, Nfld.

1983

21 puges typescript

Thank you for •the loan of this material

Merci pour le prêt de ce matériel

Canadian Museum of Nature Musée - canadien de la -natUre IABRARY/BIBLIOIÉEQUÉ • , •

, P.O. BOx. 1443, Station:1j 4 «

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Translateci from - Traduction de Russian

Into - En English

Branch or Division Direction ou Division STP1:1

Translation (Initials) Traducteur (Initiales) N. De .

Secretary Secrétariat of State d'État

MULTILINGUAL SERVICES DIVISION — DIVISION DES SERVICES MULTILINGUES

TRANSLATION BUREAU BUREAU DES TRADUCTIONS

LIBRARY IDENTIFICATION - FICHE SIGNALÉTIQUE

e re-4-S efr Author - Auteur

I.F. VePtishcheva and G.N. Tokareva

Title in English or French - Titre anglais ou français Investigations of metabolism in the Baltic cod during sexual maturation and spawning

Title in foreign language (Transliterate foreign characters) Titre en langue étrangère (Transcrire en caractères romains)

Issledovaniya obmena veshchestv Baltiyskoi treski v period polovogo sozrevaniya i neresta

Reference in foreign language (Name of book or publication) in full, transliterate foreign characters. Référence en langue étrangère (Nom du livre ou publication), au complet, transcrire en caractères romains.

Trudy Vsesoyuznogo nauchno-issledovateltskogo instituta morskogo rybnogo khozyaistva i okeanografii

Reference in English or French - Référence en anglais ou français

Proceedings of the All-Union Research Institute of Marine Fisheries and Oceanography

Publisher - Editeur Page Numbers in original DATE OF PUBLICATION Numéros des pages dans DATE DE PUBLICATION l'original

51-63 not available not available

Year Année

Volume

1978 120

Place of Publication Lieu de publication

Moscow, USSR

Issue No. Numéro Number of typed pages

Nombre de pages dactylographiées

21

Requesting Department D F 0 Translation Bureau No. 1155984 Ministère-Client Notre dossier no

Person requesting Regional Library, NAFC Demandé par

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DEC 9 1982

SEC5-111 (81/01)

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• ilk, • Secretary Secrétariat of State d'État

MULTILINGUAL SERVICES DIVISION - DIVISION DES SERVICES MULTILINGUES

Clientes No.—N° du client Department — Ministère Division/Branch — Division/Direction City — Ville

D ‘F 0 SIPB St . John ' s , Nfl( Bureau No.—No du bureau Language — Langue Translator (Initials) — Traducteur (Initiales)

1155984 Russian N. De. DEC 9 1982 -

Trudy Vsesoyuznogo nauchno-issledovaterskogo instituta morskogo rybnogo khozyaistva i okeanografii (VNIRO) [Proceedings of the All-Union Research Institute of Marine Fisheries and Oceanography (VNIRO)), 1978, V. 120, pp. 51-63

(51)* UDC 597.562:597-117.57:597-154.343

Z jA

••-• > C •••;; Lu

< g E —1 c z —

Z oog < z re n'

z tz .419. 0 F— E ô 16 1.14 I.L c Z <

Investigations of metabolism in the Baltic cod during

sexual maturation and spawning

by I.F. Vel'tishcheva and G.N. Tokareva

It is extremely important to study the processes taking place

in fish during maturation because the nature of their maturation

determines the periods of formation of spawning stocks and the size

of the recruitment.

Quite a large number of investigations has been devoted to the

maturation of the Baltic cod (Tokareva, 1963, 1967; Shirokova, 1969;

Biryukov, 1970; Lablaika et al., 1975; Dement'yeva, 1976).

This question is discussed more extensively in physiological

investigations which dwell in detail on the metabolic changes in

the females and males of cod in the process of maturation, during

the transition from one stage of maturity to another (Maslennikova,

1966, 1968; Krivobok, Tokareva, 1972; Bogoyavlenskaya, Vertishcheva,

1972; Shatunovsky, Bogoyavlenskaya, Vel'tishcheva, Maslennikova,

1975; etc.).

*The numbers in the right-hand margin are the pages of the Russian text - translator

SEC 5-25 (Rev. 81/11)

CanadU

• Liver % of

resh wt.*

(v) -vi*

V-VI

V-(VI)

7.7

5.0

2.7

(III)-IV 10.3

III-(IV) 9.6

IV 8.4

(V)-VI

v- (VI)

7.5

3.5

5.8

19.1 21.1 4.2

16.3 15.2

5.1

64.5

5.5 60.6

8.1

45.0

6.8

59.6

7.8

53.5

8.6

48.4

4.6

63.6

7.5

53.1

6.8

Table 1. Changes in the biochemical indices of cod according to the stages of maturity

g/kg of fish

Gonads Stage of maturity

' g/kg of. fish

Coeffi-cient of maturity,

Moisture content of muscle tissue ,%

Caught in May 1974 Malesof the 1970 year-class

3.2 15.0 15.4

40.9 3.8

2.4 26.2

1.9

5.7 9.9 6.2

50.3 1.4

5.7 26.8 13.8

39.4 5.4

5.3 33.6 22.9

29.8 6.1

Males of the 1972 year-class

4.0

9.0

59.5

6.4 10.3 1.6

8.6 7.7 1.9

6.8

2.6

36.6

2.1

15.1

3.3

29.0 9.1

2.4

82.0 5

81.8 9

81.3 3

80.2 6

80.7 4

81.8 3

81.1 3

81.4 3

80.5 4

Caught in March 1976 Females of the 1971 year-class

*The brackets denote which stage of maturity the fish is closer to. Note: numerator - protéin, denominator - fat.

Our data fully confirm the main tendencies of the metabolic

changes that occur during the maturation of the Baltic cod. This

paper is devoted to its generative metabolism.

The word "massa" (mass) has been translated as "weight" throughout the paper - translator

During the period of 1972-1976, we studied the cod from the

Klaipeda (Memel) area. The greater part of the samples was collected

during the pre-spawning and spawning periods. Approximately 1500

fish were caught at this time for biological and biochemical analyses.

Age, the stage of maturity and other biological indices of the cod

were taken into account when analyzing the specimens. (52

The data in table 1 indicate what changes take place in the

fish in the process of maturation, and how important it is to uti-

lize biologically homogeneous material in research.

As we can see from table 1, the reserveof nutrients in the liver,

the accumulation -(or expenditure) of nutrients in the gonads and the

expenditure of muscle protein fluctuate considerably even with an

insighificant difference in the stages of maturity.

Examples are given for the most critical stages of maturity,

when the fat of the liver and the proteins of the muscles are under-

going the most intensive redistribution in the gonads, i.e. the

transition from stage III to stage IV in females, and the transition

from stage V to stage VI in males. Investigations with the use of

radioactive isotopes (Vertishcheva, Bogoyavlenskaya, Sorvechev,

1975) have shown that stage V-VI is characterized by maximum emacia-

tion of the organism and an extremely high level of metabolism; this

is when intensive regenerative processes begin.

Gefterauve metabolism was studied mainly in second-year to

sixth-year dod. During the first two years, the immature males and

females do not differ significantly either in weight, or in the

accumulation of reserve nutrients in the liver.

29.3

28.3

315

291 (53)

16.7

14.9

6.0

5.9

Content of protein and fat in second-year immature cod (January 1972)

Length of fish, cm

Weight of fish, g

Liver Weight, g

% of P

Content, g/kg of fish weight protein

fat

Number of analyzed fish

Note: numerator - males, denominator - females.

3.3

3.0

30.4

30.1

20

11

During the period of sexual maturation which begins in the

third year in the greater part of the males and in the 3rd-4th year

in the females, metabolism differs significantly both in the level,

and in the directivity of the processes. The relative weight of

the liver is lower in males than in females, regardless of the stage

of maturity and the seasons of thé year, while the directivity of

fat and carbohydrate metabolism differ significantly according to

the stages of maturity (Bogoyavlenskaya, Vel'tishcheva, 1972).

In first- to fourth-year females, we observe a regular increase

in not only the absolute, but also the relative weight of the liver

(from 4.8 to 8.2%). In the course of their growth, nutrients rapidly

accumulate, fat from 24.5 to 45.4 g/kg and protein of the liver

from 2.6 to 4.5 g/kg per unit of fish weight; the most rapid accu-

mulation of fat is observed in third- to fourth-year females.

In males, the changes in the biochemical composition of the

organs and tissues during maturation are less pronounced, the rela-

tive weight of the liver increasing from 5.9 to 6.4% from the second

to third year. The specific content of fat increases from 30.1 to

31.4 g/kg, and that of liver protein from 3 to 3.6 g/kg respectively.

In individuals maturing for the first time (males in the second

year and females in the third), metabolism during the pre-spawning

period is quite intense, especially in females (table 2), which

manifests itself in a smaller reserve of nutrients (at the given

stage) in comparison with the next age group (males at the age of

3 years, and females 4 years), a higher percentage of moisture in

the muscles and a lower coefficient of maturity at stages IV-V.

Within the same generation of cod and the same periods of the

year, the larger individuals usually Mature earlier; they begin to

increase in length sooner, and acquire the beginnings of an annulus

and new growths on the otoliths sooner than the smàller individuals

(Tokareva, 1963). This difference is more pronounced in the female

fish, as compared with the males.

The different periods of maturation in the Baltic cod are ap-

parently due to its physiological difference. For instance, the weigh

of-the gonads in females of the same age at the 2nd stage of maturity

may vary from 0.2 to 1.5 g, and we know that the metabolism in fish

changes quite drastically even with an insignificant change in the

weight of the gonads.

de)

=.

79,9 110 0,7

79,7 8 3,Cr

79,8 4 0,6

79,9 8 0,8-

80,1 3 0,1

79,2 1 5e1.

80,3 13 0,2*

79,9 6 5,8

80,6 17 0,6

III 36,2 29,0 . 7,3 •

11 39,8 30,3 5,2

i

1972 r. 2+(3)

1971 r. 3+ (4 )

1973 r. 11-(2)

1972 r. 2+(3)

1972 r. (2+)3

1971 r. (31-)4

1973 r. 2-1-(3)

1972 T. 3+(4)

Table 2. Changes in the metabolism of maturing fish

Year Of 4c.t.; 0 u .... ' 9

• wo • 44 E Liver. • 4-1

44 .4.., e:k. . a $4 4.>

hatching 4 3 0 e 4-1 ‘

(1) $4 4-) 4 4 4-1 .e i 4 a) - and - age tr, e CI La CI 0 4-4 DI ' , ime tn 41 g 4

(C1 41 e • .4 -1-1 el 0G) ..-N4 .to .r4 e. • e 4 4 mt CD •4-I , CL) de) , 44 '.•1-1 0 0 CA

CO 5 a e dl) 44 tn tm Z C.) el,

Caught in March 1975 Females

7.9 3.6 • __ _ • _ _ 11

47,7 21,6 7,0 4,4

57,3 35,8 9.1 4,4

52,3 25.5 7,0 4,5

11-111 • 4 3,2 73.1 7,7 .. -i-876 37,8 • • Males •

9,0 3,2 11 31,3

" 49,7 • 9,5 4,0

III-1V 31,3 .9,4 4,5 51,4 21,5 10,8 3,5

34,4 12,7 3,6

7,2 3,5

111-1V • 37,1 24,1 5'8 58,0 25,5

Caught in May 1975 Females

8,7 3,3

. 3:5.4 15,6 . 4,0 -974 T877

7,8 3.3•

11-111 35,0 15'0 " 27,77

8,1 4,6 II 41,6 34 .5 5,8 89,7 26,1

5,7 4.1

• 19,8 •

5,2 35,8

79,7 1 1,5

80,7 16 0,8

80,4 5 1,5.

2 '2,8

2 0,7

2 1,4 :4'

11-11I 48,5 80,4 8,4 65.9 47.7

Caught in March 1976 Females

_!2 11 35,5 21,1 5,5 - - 79,9 11 0,5.

54,5 27,4 8,7 5,4

11-111 42.4 4§,9 6,8 5-47 i3-7-5 • 80,3

8.5 3.2 ' 11 40,9 24,7 4,3 - - 80,1

52,7 19,6 6,9 4.3

11-111 41,9 40,3 7. 1 587-6 3--67 80,4

Note: numerator - protein, denominator - fat.

-7-

(55)

Table 3 contains data on the changes in the biochemical indices

oi 2- and 3-year-old female cod at the 2nd stage of maturity. The

material has been divided into three groups according to the weight

of the gonads, i.e. 0-0.5 g, 0.6-1.0 g, 1.1-1.5 g and greater.

Table 3. Changes in the biochemical indices of female cod at the 2nd stage of maturity in relation to the weight of the gonads

bi .•. .. . Year of:• Weight A Iiver • 4

•

.ri

•

4 . r . k 4.; I • ., hatching giinads, r ;g,„,. 4-01 -a%) 4; Pe) 4.; 49 el;! de r. ' and age

g .i-i a "..-4,1 ), ftS ',5 -

0 tl) • JP del-I t714-1 Z X• . .u

•

• 4 '.` . Càught - in November 1972 • .- 9. 87 3,04 . . • 1 - .

0-0.5 , 30,0 8,0 . 3,3i'iti:i . ' -1-17-8 0.21.: . 1 .

.. .• .. • : I - i:: • - • I • - - 8.66 . 4.51 ( 1970 r.

0,6L-1,0 . . : 30,2 '16,1 . 6.3 "4-Fc79— -2-57-• 0.37 8 • (2 4) q 6.12 - - 5,34 I

1,11--3,5 28,3 23,3 . 10,2 58.23 — - - — 0.6 . 7 3 ;

50.81 • - •

12.49 .• 5,94 0-0,5 32,5 16,8 5,4 3837 18 26 0.16 4 I

9,04 5.49' • • ,2 . — 5 1969 0,6-1,0 32,4 22,4 7 . 46,65 28,32 0 ' 31 (3

r.1- )

7,27 5,12 1,1-6,0 36,2 35,5 8.3 0.78 24 j

56,23 39,61

.• Caught in March 1974 . . 6,3 . , 4,0

2,0-4,5 42,2 43,7 7,5 — — 0,80 11 ' .3i.

' . C a5U9;711..t.-. 38 ' 0 111 May 19_74 6.4 3,5

1.1-1,5 37,4 24,0 6,5 . — 0,40 1 1970 r. 55,8 30,1 (4)

Note: numerator - protein, denominator - fat.

The lowest level of metabolism corresponds to the minimum

weight of the gonads within each age group. The fish in this group

have the lowest relative weight of the liver and the lowest specific

content of fat.

The size composition of all three groups is essentially the

same, i.e. 30.0--30.2--28.3 cm for (2+), though they differ greatly

in the intensity of metabolism. Only in the fourth year does the

group of fish with the highest condition factor outstrip the other

individuals of the same age in growth (table 3).

It can be assumed that 25% of the.fattest 2-year-old females of

group III (2+) will mature by the following spring, i.e. will become

of commercial value •n-the third year, and those of Ctoup II in the

fifth year.

On the basis of long-term data, cod with a better rate of growth

constitute. up to 75% of the landings, while slow-growing cod that

spawn in autumn (in September-October) constitute not more than 10%

of the catches (Tokareva, 1967). Thus, a small group of fish (8-12%)

with a low metabolism makes up the group of slow-growing cod. Of

course, these figures may fluctuate within a certain range, depending

on the specific conditions of the year. (56

Thus, the given example shows the possibility of differentiating

fish -ôf thé same generation according to their physiological condi-

tion.

The references listed above present fairly complete data on

the metabolic changes that take place in the process of maturation

during the transition from one stage of maturity to another according

to the age of the cod.

Thus, we have discussed the physiological differentiation in

immature fish at the 2nd stage of maturity. Apparently, this type

of physiological difference also exists in maturing individuals of

an older age. This can be traced only in fish of the same age and

same stage of maturity under the specific conditions of a given

year.

As we have already mentioned, with this physiological difference

in maturing fish, the individuals with a More intense metabolism

should mature earlier in the year. Therefore, in order to obtain

the physiological characteristics 6f cod belonging to the same

generation and varying in the intensity of their metabolism, we must

compare fish of the same stage of maturity throughout the entire

pre-spawning and spawning period. (57)

Table 4 contains data on male and female cod at the same stage

of maturity during different seasons from the onset of maturation

to mass spawning. Despite the fact that these data are of a some-

what fragmentary nature, a number of tendencies can be traced quite

clearly.

At all the stages of maturity [from II to IV (V)], the content

of fat and protein in male and female cod of different ages increases

towards winter and decreases in May. The relative weight of the

liver and the amount of fat per unit of fish weight change according-

ly. The protein reserve in the liver is more stable, but as we have

seen earlier, the protein demand is fulfilled mainly by means of

the muscles. It proceeds from table 4 that the water content of

the muscles of maturing fish increases by May. The difference bet-

ween the maturing individuals is similar to that observed earlier

for fish at the 2nd stage of maturity (see table 3). The seasonal

change in the metabolism of younger individuals (2+, 3) does not

affect the size of the fish; 4+ cod already differ not only in the

level of reserve nutrients, but also in size (within each age group).

.1 NOV. 1972 r. . :1973 r. }:

*March. 1972 r. •eaYr.,

1975 r.

'SaY • rch 1972 r.

• • ZtY inarch 1976 r.

. .

UOV. 1972 r. reb. 1973 r. NOV. 1972 r.

1973 r. 'NOV 1972 r. eeb.. .1973r. ean.

March_. ,.raY Zan. rch a.y

ay r-ch I

Maech ela.rch t. 1976 r. 'MaY

A9.1.Y.

1972 r.

1975 r.

Liver

fiitu ,

0 O1-1 4) 14W ni

dP -1-) 4-1

-F e m. a 1

0

4-)

4)4-; cti 4-1

es

44 0E

0 ed

tT e a) .1-1

0 tr)

tyle

•1-1 e ACV • 444..)

e t nom- 4:0

.0

-.g

9-1 trn 44 • o: o

4

mid tt, " tr tr.;

4-1 ai 4'4 >;.1 4-3

• tr)

Table 4. Seasonal changes in the metabolism of female and male cod at the same stage of maturity

• Tithe of •elitimmpling

41,4 793 9,5 5,4 4741 11,6 - 8 44,0 880 8,3 5,7 39,6 1,1 1 33,8 439 7,6 4,5 36;1 0,5 80,3 16 34,4 404 7,1 3,3 34,4 0,6 80,6 10 34,0 351 5,5 3,6 , 27,9 0,7 80,6 7 45,7 1014 9,0 4,8 41,6 3,4 79,8 8 42,3 758 7,1 4,9 31,6 5,6 80,2 5 37,0 470 8,3 5,6 38,3 9,5 80,4 1 37,5 535 7,6 5,2 26,7 17,4 81,5 2 56,5 1752 8,4 5,3 29,0 .22,9 81,8 3 49,4 1.141 5,9 5,1 20,0 13,2 81,7 2

Males , . 37,2 547 8,9 6,1 41,6 0,8 - 3 33,0 330 5,5 3;1 30,1 , :1,5.. - 4 36,2 537 10,5 5,2 '51,5 1,2 - 3 37,1 540 8,0 5,4 39,9 2,3 - 4 42,8 897 9,4 5,3 44,9 2,1 - 3 40,5 • 663 7,5 3,9 37,6 2,8 , 3

•34,4 447 6,4 3,6 31,4 0,4 80,5 14 33,2 358 6,6 3,3 34,8 0,5 80,7 6 34,4 378 5,1 .3,4 24,7 0,2 80,4 6 39,5 700 9,5 2,9 36,9 12,5 79,7 2 33,0 545 6,8 3,3 31,0 :14,3 80,8 2 35,7 431 6,2 2,4 26,5 10,3 80,9 3 35,7 477 6,1 2,8 29,7 • '11,6 79,6 8 35,0 474 5,1 3,6 22,0 13,2 80,0 2 51,9 1229 5,0 2,8 27,6 ' 9,5 80,2 • 2 54,5 1586 • 4,8 2,3 24,4 13,1 80,9 1 52,7 1549 7,5 2,6 36,6 . 21,9 81,1 3 4.7,5 .1090 6,9 2,8 •35,4 .16,6 .81,4 4

• . .

.1968 11-111441

1969 III 3

1971 III-1V 4 i

1969 IV 3 -1

1971 IV 5

.1969, 34

1969 III

1968 III 4-gil

1969 II 3

1969 V 3 A

.1972 IV 31

1970 IV 6 -

1971 V '4 1.?

As our investigations have shown (tables 5, 6), the type of

metabolism in cod depends on the conditions of a specific year

(hydrologic conditions, the food supply which determines the growth

of individuals, etc.).

Analysis of the data presented in table 5 points to a synchro-

nous change in the content of reserve nutrients in male and female

cod according to the years.

Table 6 contains data on the changes in the biochemical indices

of 4-5th‘-year female cod. The samples were collected in March and

. 10

13 .a7

32

4

3

10

6

1972

1971

1970

1969

1975

1974

1973

1972

Year I of hatching lof sampling

9.5 7,7 7,1

4.1 4,5 4,3

45,9 48,2 41,9

8,1 7,2 6,3

51,0 37,8 36,6 37,8 33,3 29,0

43,4 42,8 41,8

5,2 4,9 4,2 •

8.4 4,8 5,5

9,3 9,0 9,7

45,7 45.7 43,4

35,4 41,6 45,6

1 .6

3,8 2,5 2,5

80,5 79,8 80,1

80,7 79,9 80.4 80,8 3 79,8 17 80,1 8 81,1 79,8 79,8

2 8 5

12 4 2 10 8 2

IV

V

4 1,8 2 0,6 2 9,3 9 9

• 1I

11-1I1

In

11-1. I to O rd

e 4-1 e4-1 -r4 131)

f4-P-ts%

0,6 0,3 2,2

May during 1974-1976, and cod Of the 1969-1972 year-classes were 4 analyzed.

Table 5.Reserve of nutrients in female 4numerator) and male (enominator) cod at the 2nd stage of maturity, caught in March during different years at the age of 2+

Liver, g/kg of fish weight protein fat

3.6 21.6

3.5 13.6

3.7 30.6

4.0 34.7 .4 .3 28.6

4.4 28.8

3. 3 34.4

3.3 34.8

Length of fish,

cm

35.8

34.4

35.6

35.0

30. 4

30.5

34.4

33.2

Table 6. Change in the biochemical indices of maturing female cod caught during different years

19741970 1975 1971 1976 1972 1974 1970 1975 1971 19761972. 19741970 19751971 19761972 1974 1970 1975 1971 19761972

4theyear fish caught in 42,6 7.7 4,2 40,7 0,6 13,5 1,9 39,8 5,2 4,4 25.5 0,6 - 40,9 4,3 3,2 19,6 0,7

0,8 13,7

0.8 --

1,4 13,9

4,1 18,Ç

3,2 16,1

3,4 16,2 10,9 21,7 4,7 3.4 20,5 3,4 6,5 20,1 3,2

1974 1969 1975 1970 1976 1971 1974 1969 1976 1971

Sth-year. fledi caUgh-ts-in May

51,3 8.6 5,8 30,8 17,6 19,3 3,9 82,7

53,1 8.8 5,6 35,9 8,3 22,9 3,7 80.3

49,4 5,9 5, 1 20.0 13,2 22,2 4,0 81,7

52,6 9,3 6.0 31,8 29,7 12,7 3,0 83,6

54,0 8,9 5.5 26,1 38:9 12,2 2. 6 83.7

Stage I of eleg-rity

The year 1974 was characterized by favourable hydrologic con-

ditions and harmonious spawning of cod which took place during

periods approximating àvèrage-ones for several years.

The year 1975 was an atypical one as to hydrologic conditions.

The spawning of cod was lengthier. Individuals at the 3rd and even

2nd-3rd stages of maturity were encountered in May.

1976 was characterized by satisfactory hydrologic conditions,

but according to BaltNIIRKh* data, the spring food supply for cod

was low. Thé year was distinguished by an early onset of maturation

in the fish. The older age groups were already at the 4th and 5th

stages of maturity in March. However, it is possible that because

of poorer feeding conditions during maturation, the spawning period

was lengthier and the main part of the fish was still at the 4-5th

stages of maturity in May.

At the 2nd stage of maturity and at the onset of maturation

(stage-II-III), the cod caught in 1974 were distinguished by a much

higher relative weight of the liver and fat reserve (see table 6).

These indices in the fish caught in 1975 and 1976 were quite similar

(the supply of reserve nutrients in cod was somewhat lower in 1976). 58)

The moisture content of the muscles and the maturity coeffi-

cient were practically the saine in all the three groups of fish.

The coefficient of maturity was somewhat higher in 1976.

At the 3rd stage of maturity, we-still observeaa regularity in

the distribution of reserve nutrients in the fish of all three groups,

but the cod caught in 19744ae already less different from the other

two groups. On the other hand, the relative weight of these fish was

the highest (see table 6).

*the Baltic Scientific Research Institute of Fisheries - translator

The cod caught in 1974 at the 3rd-4th stage of maturity was

characterized by the lowest fat reserve and the highest content of

moisture in the muscles. The relative weight of the gonads was

three times as high as in the fish caught in 1975. The cod of 1976

occupied an intermediate position as to the weight of the gonads.

At the 4th stage of maturity, the maximum weight of the gonads

was noted in the cod caught in 1974 (17.6%), then in the cod caught

in 1976 (13.2%) and finally in the cod caught in the unfavourable

year of 1975 (8.3%). During this period, the fish occupied the re-

verse order as to the reserve of fat, i.e. the highest specific con-

tent of fat was noted in the cod caught in 1975 (35.9 g/kg), then

in the fish caught in 1974 (30.8 g/kg), and the lowest in the cod

caught in 1976 (20.2 g/kg). Apparently, the poorer feeding condi-

tions during the spring of 1976 (according to BaltNIIRKh data) re-

quired a greater load on the organism for the completion of gonadal

development.

The moisture content of the muscles also varied according to

the coefficient of maturity, i.e. the highest moisture content (82.7%)

was-moted with the maximum coefficient of maturity, 71.6% (1974), and

the lowest moisture content (80.3%) with the lowest maturity coeffi-

cient, 8.3% (1975). (59)

Apparently, the conditions of the habitat during maturation

and spawning influence the level of metabolism in cod, which in turn

determines the weight of the genital products and the quantity of

spawned eggs. Moreover, the intensity of metabolimm in fish of the

same generation may vary according to the specific conditions of

the year. For example, the,nutrient reserve and the maturity coeffi-

cient were the highest in the 1970 generation 6f cod caught in 1974

(see table 6), and the lowest in comparison with other groups of

fish in the cod caught in 1975.

Table 7. Content of fat and protein (in g/kg of fish weight) in different generations of cod caught in March

Females, 3rd stage of maturity Males, 4th stage of maturity Pro- Length Year Pro- Length Year

Fat tein' of fish caught of Fat tein of fish caught of (cm) latching (cm) hatching

2+(3) 22.4 2.7 34.5 1972 1969 31.0 3.4 35.6 1972 1969

3+(4)

46.4 5.4 40.1 1973 1969 35.6 3.2 37.5 1973 1969

33.3 4.9 42.8 1975 1971 47.5 4.0 42.8 1974 1970

4+(5)

42.7 4.7 43.5 1973 1968 43.2 3.8 52.9 1974 1969

43.9 4.9 49.6 1974 1969 27.6 2.8 51.9 1975 1970

5+(6) 50.3 5.0 61.0 1974 1968 22.1 3.1 61.0 1975 1969

It was quite complicated to trace the metabolic changes in fish

of the same generation over a number of years, and to compare several

generations. In addition to certain fluctuations in generative meta-

bolism, we observe clearly defined age shifts during maturation. If

maturing third-year females were at the 2nd-3rd and 4th stages of

maturity in May 1975, then the sixth-year females -were at the 4th and

5th stages, and the eighth-year females at the 6th and 6th-2nd stages.

During different seasons and years, the degree of discrepancy between

the stages of maturity with respect to age varied, but the tendency

-14as preserved.

The age changes in nutrient accumulation can be traced in

general in the 1969 generation of male and female cod (table 7).

Metabolism is intense in the third-year females maturing for the

first time; the amount of fat and protein is minimal. After that,

it increases up to the age of five.

In 3rd to 5th-year male fish, the fat reserve increases somewhat

with the amount of protein approximating it. Signs of aging appear

in the sixth year. However, in fish of the same age taken for analy-

àis from different generations during different years, the main ten-

dency will increase in some cases and diminish in others. For exam-

ple, the very sudden decrease in the fat reserve of the 1969 genera-

tion of 4-year-old and 5-year-old males from 43.2 to 22.1 g/kg was

caused not only by age changes, but also by the unfavourable condi-

tions of 1975. The female fish of the same age (1968 generation)

could have shown the first- signs of an age-induced decrease in the

intensity of metabolism, but this did not occur. On the contrary,

this group of fish showed the highest reserve of nutrients, which

was probably due to the favourable conditions of 1974. (60)

Let us now look at the 4-year-old fish. In the female fish

of the 1968-1969 generations caught in 1973-1974, the reserve of

nutrients was similar, i.e. 42.7 and 43.9 g/kg of fat and 4.7-4.9

g/kg of protein respectively. Despite their similarity in size .differedj

(52.9 and 51.9 cm), the male fish of the 1969 and 1970 generatiàn

immensely in the reserve of fat (43.2 and 27.6 g/kg) and protein

(3.8 and 2.8 g/kg). The fish with a high condition factor were

caught during the favourable year of 1974, and those with a low

nutrient reserve during the unfavourable year of 1975.

4é1 61 Liver • i

%IA 0.) e

ro- t tr) % of fish "qt

P in' rfat

g/kg of

Table 8. Content of protein and fat in the gonads of male and female cod of different ages

• Cln•nagiR. OcP

gatu- % fof. fre-sh ei) '4:i t-,iof :gonad eg Leirl fat ô pro- o

rIzy • eoef, ticie

. %

• 6 8.

4 5 6 7

. F.' 'e m a 1 e-s : 3rd-4th stage àf maturity ,(caught in March 1974)

44,8 8.2 . 19,4 3,4 81.0 6 ' 17,2 4,5 21,8 3,6 81,0 1 -:

maturity (caught in March 1976) • 5.8 • 28,2 16,2 • .19,9 3,8 81,4 4 . 5,3 29,8 22.9. 19,9 3.6 81,8 3

5,5 38,6 • 15,5 22,9 3,5 81,9 4 5,6 - 36,4 '1.1,7 24,8 3,8 80,8 1 .

.4t1 stage of maturity (caught ln May 197à.

60.3 10.0 5,3 85,0 4,2 3,6

.4th stage of

41,2 8,0 56,5 8,4 62.6 • 9.0 76,0 8.6

6 • 7

8

3 4 5

8.2 11.2 8,3 9,4

11.8 13.8

35. 1 6.9 5.2 25,4

44.8 10.2 7,6 37,7

53.1 8,6 , 5,6 35,9

61.3 8,5 5,2 36,8

51,0 • 12,7 10,8 31,9

73.3 12,1 7,7 43.0 _

21,5 • 3.4 23,0 3,8 22,9 3,7 19,3 2.8 17M 2,3 48,4 2.9

80,5 5 80.9 .8 80,3 2 80,8 4 81.8 1 81,6 3

5th stage of maturity. (caught: in May .1976) 3 4 5 6

3 4 5

.6

36.1 5 1 3,8 13,1 • 27,4 MA 2,1 83,9 2

45,4 6,7 . 6,1 19.6 35,2 11,3 2,0 84,0 6

54.0 ' 8,9 5,5 26,1 38,9 1 9.2 2.6 83,7 9

60,0 9,4 6,3 29,4 MA 12.5 2,6 83,7 3 Males

4-5th stage of maturity (caught in March 1976) 80,5 5 79,1 8 81,1 14 81,2 8 80,0 1

37.0 41,8 53,7 61,1 716

4,8 4,3 5,9 4,6 4,1 •

2,4 2,3 2,7 2,2 2,0

23,9 21,4 '31,4 22.0 18,7

10,7 12,7 14,5 13,8 16.4

12.1 UM UM UM

2,9 2,9 2,7 2,6 2,7

3 4 5

.6

Sth stage of maturity (caughtin -March 1976) 34,7 re . HA 2.4 • 804 2 . 36,6 21,1 m. • 2,7 • 81,1 3 3641 21,3 HM - 2.4 MM 5

• 24,5 ' 20,7 12,4 2,5 MA 5 •

37,2 6,2 2,7

52,7 • 7,5 '2,6

55,3 • 7,2 2,5

62,6 • 6,7 1,9

4. 5 6

5th stage of

47,5 6,9 2,8

60,5 6,6 • 2 7

58,0 6,6 2,5

maturity-(caupet_

35,4 46,6 . .13,2

33,1 14,7 e.5

33,7 • 17,7 12,0

in May 1976) 2,8 81,4 4

MM M 2,5 81,4

•••

1969 and 1971-generation female fish at the optimal age of 3+

caught under the dissimilar conditions of 1973 and 1975 differed

greatly in their nutrient reserve (fat 46.4 and 33.3 g/kg, protein

5.4 and 4.9 g/kg of fish weight). This example shows how the age

tendencies of generative metabolism are affected by the "quality"

of a given year.

So far, nobody has indicated to what extent all of the noted

fluctuations in the metabolism of the parent fish affect the quality

of the gonads themselves.

One might point out the main tendency, i.e. the change in the

percentage of protein and fat in the gonads according to the stages

of maturity (these changes are negligible in the male fish as com-

pared with the females). The content of protein in the testes from

the 3rd to 5th stages of maturity varies from 11.9 to 13.2% of the

fresh weight, and the content of fat from 2.2 to 3.2, rarely up to

3.8%. The differences according to maturity stages are more signi-

ficant in the female fish, especially in the protein content; the

gonads contain 14-16% protein and 2.5-3.2% fat at the 3rd stage of

maturity, 19.9-23.5% protein and 3.4-4% fat at the 4th stage of

maturity, and 11-12.6% protein and 2-2.8% fat at the 5th stage of

maturity.

Table 8, which contains data on 3rd-8th-year female cod and

3rd-7th-year male cod, indicates that the content of protein and fat

in the gonads remains practically unchanged for each stage of maturity (61

The age tendencies of change in the relative weight of the

liver, the fat reserve and the moisture content of the muscles are

traced quite clearly. One can trace how the very intense metabolism

in third-year females maturing for the first time and the decrease

in the content of reserve nutrients in aging males and females (after

the 5th -6th year) results in a decrease of the maturity coefficient,

5

5

-18-,

i.e. a decrease in the weight of the genital products. The content

of protein and fat in the gonads remain similar for the given stage.

The fluctuations in the protein and fat content of the gonads

are also insignificant in the cod caught in March and May of dif-

ferent years (table 9).

Table 9. Content of protein and fat in the gonads of females at the 4th and 5th stages of maturity, caught in March (numerator) and May (denominator) of different years

.. ii. tn ék.g/kg of ?ored;re if •116 ti-

ti..up •

'e ehl fish wt. - of e .4 .. o ‘H

of- - 44 - '91 4i e i-1 n 0 t prof-- ' o..-i tell.' a'at ein- Fat s'e),.', o _ oei tde

• te v. 4 • P.;

P il 4th stage of maturity--.-. • e

9,5 8,3 47,4 5.6 38.a 22.7 6.9 80.4 37.0 1 197 2

17.4 7,6 46,5 5,2 26,7 22.5 4.-8 81,5 37,5 2 .

16,2 8,0 46,7 5,8 28.2 19.9 3,8 81.4 41,2 • 4 nm

18,2 5,7 4272 4,4 18,8 21-,9 3.4 82.1 39,5 I

14,9 12.0 51,4 6,5 45,2 23,3 2,7 79,8 56,8 1. 1975

8,3 8,3 53-75 • • 5,6 35,9 • 22,9 3.7 80,3 53,1 2 22.9 8.4 48.4 • 5,3 29.8 19,9 3,6 81,8 56,5 3 1976

13,2 5,9 41.8 .5,1 20 b 0 22,2 4,0 81,7 49,4 2 . .

. 5.th: stafie- ,of-Inaturcutty • 6.2 9,9 48.9 5.9 .31,2 14,7 2,5 83.7 56,1 6

76. 38.9 • 8,9 45,7 5,5 26,1 12, 9 2,6 83,7 54,0 9 19.

40,9 11,2 51,4 6,3 36,2 15,8 2,7 83,7 61,7 2

31.1 9, 4 45,7 6.73 29,4 12,5 2,6 83,7 60,7 3 1976

(62) Observations over several years have shown that complex inter-

relations exist during the accumulation of reserve nutrients, but

that none of the age-induced metabolic fluctuations • that vary with

the season or conditions of the year have practically any effect on

the quality of the genital products, though the reserves of protein

and fat in the parent organism.may vary significantly. A small

• leig U

Age ri 4r1 4 14

3

reserve of nutrients causes a decrease in the weight of the genital

products, which can affect the quantity of spawned eggs.

Conclusions

1. Up to the onset of sexual maturity, male and female cod do

not differ significantly in the level of metabolism.

2. With the onset of maturation, the metabolism in female cod

can be considerably higher than in male cod. The metabolism of fe-

male cod maturing for the first time in the third year is particularly

intense.

3. Second- and third-year females at the 2nd stage of maturity

may begin to differ in the level of metabolism, which results in the

appearance of early- and late-maturing groups of fish.

4. The earlier maturing individuals among the fish that have

begun to mature are characterized by a high level of metabolism.

5. The "quality" of the year may affect the metabolism of cod,

which in turn affects the periods of maturation and the quantity of

spawned genital products.

6. None of the fluctuations in the metabolism of the parent fish

have any significant effect on the quality of the genital products.

References

1. Biryukov N.P. Baltic Cod. Kaliningrad, 1970, 168 pp.

2. Bogoyavlenskaya M.P., Vel'tishcheva I.F. Some data on the age-dependent changes in adipose and carbohydrate metabolism in cod from the Baltic Sea. Proceedings of VNIRO, 1972, v. 85, pp. 56-62.

3. Velitishcheva I., Bogoyavlenskaya M.P., Sorvechev K.F. Participation of some C 14-labelled amino acids in the metabolism of Platichthys flesus L. during the post-spawning period. Proceed-ings of VNIRO, 1975, v. 96, pp. 63-68.

-20- ,

4. Grauman G.B. Changes in the biochemical composition of the eggs of Baltic cod females, depending on their morphobiological characters. Proceedings of VNIRO, 1972, v. 85, pp. 63-67.

5. Dement'yeva T.F. Biological Basis of Commercial Forecasts. Moscow, "Pishchevaya promyshlennost" publishing house, 232 pp.

6. Krivobok M.N., Takareva G.I. Weight dynamics of the body and individual organs of the Baltic cod during maturation of the reproductive organs. Proceedings of VNIRO, 1972, V. 85, pp. 46-55.

7. Krfiger G. Formation of the recruitment of Gadus morhua L. and Sprattus sprattus L. in the Baltic Sea. Author's abstract of dissertation for the scientific degree of Candidate of Biological Sciences, 1974.

8. Lablaika I.A., Lishev MN., Uzars D.V., Khoziossky S.A. Composition, condition and utilization of the stock of Baltic cod, and its importance in the food chains of the sea. Fishery Investi-gations of the USSR and the German Democratic Republic in the Baltic Sea Basin, 1975, pp. 31-37.

9. Maslennikova N.V. Content of fat in the meat, eggs and liver of Baltic cod at different stages of its development. VNIRO Symposium of Scientific and Technical Information, 1966, No. 12.

10. Maslennikova N.V. Relationship between the physiological condition of the Baltic cod and certain characteristics of the chemi-cal composition of its muscles, liver and ovaries. Author's abstract of dissertation for the scientific degree of Candidate of Biological Sciences, 1968, 25 pp.

11. Tokareva G.I. Some data on the growth characteristics of the Baltic cod. Proceedings of AtlantNIRO, 1963, No. 10, pp. 179-192.

12. Tokareva G.I. Population dynamics of the Baltic cod in con-nection with the peculiarities of its biology and fishery. Author's abstract of dissertation for the scientific degree of Candidate of Biological Sciences, 1967.

13. Shatunovsky M.I., Bogoyavlenskaya M.P., Vertishcheva I.F., Maslennikova N.V. Investigations pn the generative metabolism of the Baltic cod. Proceedings of VNIRO, 1975, V. 96, pp. 57-62.

14. Shirokova M.Ya. Rate of sexual maturation dñ the generations of Baltic cod caught by commercial fisheries in 1961-1963. Proceed-ings of VNIR°, 1969, No. 21, p. 37.

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ii C M eHTbesa T. O. Snoaortutecsoe o6ocHosaHne HpONIMC.10131,1X Hp0F11030B. M., 113A-130 «1111L11,eBaH s 01)031b1111.1eHHOCTb», 232 c.

K p st so6os M. H., Tosa pesa r. H. Attisaminta sen Teaa ii oTaeateibtx °pra-mes 68.-rrnficsoft Tpecuet npa co3pesaHint 110.10BbIX opranos. Tpyubt BHIIPO, 1972, T. 85, c. 46-55.

K p p T. 0opmeiposaane nono.THemia 3anaca Tpealt (Gadus morhua L.) es setabset (Sprattus sprattus L.) Ba:nritficsoro stops. AsTopegtepaT AuccepTaulut Ha mute ries«, crenetin saita. 6H0.101". Hays. 1974, c.

JI a 6 .1 a ils a H. A.. .TI et tu e M. H. Y3apc JI B., X03HOCCKH C. A. Co-craie. cocToeutHe H 91:CrlayaTall.HR 3attaca *ianTiiiicsoft Tpecitn H ee 311atietine B mutteaux ueneix stops. Pbt6oxo3e.icneemble itccaeuosartita CCCP H r.n,P B 6accertHe Saarealcsoro stops, 1975, c. 31-37. .. •

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• - • • . . •

• Investigations of metabolism in Baltic .co. d . in the maturation and spawning seasons

• - • • ••• • i! Veltishcheva 1. F.:, "

.::.,Tokareva t .

SUMMARY .•

. • The long-term investiga-tioris of metabolism in Baltic cod 'have indicated no noti-

ceable difference . in the metabolic rates in immature males and females. With the onset of maturity they become different. The most intensive metabolic rate is observed in specimens at lirst maturity, in lemales in particular. Specimens with a great amount of nutrients attain maturity earlier.

The biotic and abiotic conditions of the year may affect metabolism of cod which governs the time of spawning end number of sexual products spawned. Fluctuations in the metabolism of parents do not affect the quality. of sexual products.

DUE DATE

to 1

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