CM_1969_special_meeting_08.pdf (516.9Kb)

This paper not to be cited l'ri thout prior reference to the author International Council for the

EXploration of the Sea C.M.1969

Special Meeting

liThe Biochemical and Serological Identification of Fish Stocks"

No.8

The Relationship between Arctic and Coastal Cod in their

Immature Stages illustrated by Frequencies of

Genetic Characters

by

Dag M0ller*

*

^{Mr. Dag} ~ller~

Fisheries Research Eoard,

Eiological Station9

st.

Andrews9 N.E.

Canada.

The Relationship between Arctic and Coastal Cod in their Immature stages Illustrated by Frequencies of Genetic Characters

The cod, Gadus morhua L., "Which inhabit the Norwegian coast and the Barents Sea9 form two genetically separate populations (M011er, 1968 a). In spite of

the simultaneous spawning in the same areas the two groups Qf cod have significant differences in frequency of the haemoglobin BbIl allele (Sick? 1965) and of the blood types A and E (r~11er9 1967). The investigations did not record possible gene flow from one gene pool to another 9 implying that the Arctic and the coastal cod should be regarded as ~vo sibling species (M0l1er₉ 1968 b).

The material presented in this report consists of two main parts~ 14 samples of cod fry (Table 1)9 totallL~g 914 specimens? from the Vestfjord, Troms, and

Finnmaik area; and 48 samples of young cod (Table 2)9 of which the majority were from 3 to 6 years old, totalling about 5.000 specimens, from different localities in northern Norway and in the Barents Sea.

During trawling ~~d long-line fishing the depths were recorded by an

echo-sounder, and the approximate mean depth of the different sampling localities were calculated. Some of the samples were collected with shore seine and trap- net. ~ne depths for these samples were estimated to 2 and 15 m, respectively.

The fry blood specimens were acquired from live fish by cutting the tail, While the other blood specimens were obtained by heart puncture of live cod.

~ne handlL~g of the specimens, the method used in the haemoglobin determinations, the blood grouping technique, and the explanation of the nomenclature have been described elsewhere (Sick, 1965; ~Eller, 1967). However, the blood type E frequency of 9 samples, collected in 1963, was not determined due to lack of anti-sera at that time.

Table 3 gives the distribution of the haemoglobin patterns, the frequency of the HbIl allele ('1¹)9 and the depth of the cod fry samples. The frequencies of the samples vary betvreen .088 (sample 7) and .432 (sample 8), and the

frequencies differ significantly among samples taken in the same fj ord (sample 1-3, 4-7, and 8-9) and in the same year (sample 4 and 69 5 and 7, and 8 and 9).

The differences be~vern these pair of samples from the same fjord are similar with high values of q in shallow vlater and with low values in deep vTater.

However ⁹ the frequencies have about the same value in the samples 1 and 2, or the difference is contrary 1ri th slightly higher values in deep water in the samples 10 and 119 and 12 and 13. Regarding the difference in depth between the samples 11 and 13, and the samples 29 39 6, 7, and 9, the main impression is that the frequency of the BbIl allele varies to a certain degree wi.th the depth;

the lowest values being in deeper water.

This relationship is supported further by treating the samples as

grouped data. The depth versus the mean frequency of the samples belonging t·o the same 50 m class is plotted in Figure I. Only the frequencies between 51 8l'1d 150 m do not apPlar to fit in the diagram of correlation betvTeen depth and frequency of the BbI allele.

The distribution of haemo~lobin patterns, the values of '119 and of the frequency of the blood type E

(~),

together with the depth of the collected samples of young cod are listed in Table 4.

In Figxres 2 and 3 the values in samples from different lo~alities of '11 and ~, respectively, are represented on a map of northern Noniay and the Barents Sea. In localities which in Table 2 are represented with two or more samples, the values in the maps represent the means.

The highest values both of '11 and pE are found inshore (Figures 2 and 3) ⁹ whereas, mostly all of the values in samples from the b~s appear to be

comparatively low. In most of the fjords with more than one sample, the sample with the lovJest value of '11 and pE l~ found !.r.b'ar the mouth of the fjord.

- 2 -

However, the fig~es contain more frequencies which do not fit into - this general pattern. Therefore, the vaues of ql and pE according to the depth of the sample are plotted in Figs. 4 and 5, respectively. Incidentally, the samples collected inshore and the samples within the coastal locality form four different groups as indicated on the figures.

Both in Figures 4 and 5 the frequencies are decreasing with

increasing depth. Although there are large variations from one sample to another, the values of the estimated means in each of the groups both for ql and pE are decreasing continually with the values • 312 and .920 , respectively, near the surface to .109 and .300 at 300 m. The decline in the values of the frequencies appears greatest in the first 100 m.

The values of ql and pE in samples from the sea are 101:Q ~Figs. 4 and 5).

Only one sample (sample 39) has intermediate values of ql and P'9 while the others have low or lo"rer values than the samples collected inshore in

corresponding depth.

The value of ql according to the value of pE in tn~ l:lrurte sample is plotted in Figure 6, together "Ti th values representing spmming groups of Arctic and coastal cod in the Vestfjord and north to the Laksefjord (M011er, 1968 a). Here too, there are large variations from one sample to another.

However, the values correlate (correlation coefficient .77), and the data fits a straight regression line (y = .089 + .179x; linear regression coefficient = .179, highly significant P .01) • The mean values of the Arctic cod spawning groups fit tIllS line, 'while the values of the coastal

cod spawning groups are slightly different.

1 Tables 1 and 2 list the haemoglobin patterns

1

the homozygotes RbI /RbI,l and RbI2/RbI2 ; and the heterozygote RbI /RbI2 , in the cod fry and young cod samples, respectively. The total numbers of individuals in several of the samples are Im·[, and the observed numbers of the different patterns of the individual samples in the tables deviate slightly from the expected numbers calculated from the Hardy-vleinberg law of genotype

distributions in large random mating populations. How'ever, by treating the samples in larger units it is possible to detect unconformity. The

observed and expected distributions of the haemoglobins in cod fry are not in accordance:

RbIljRbIl

- - - -

RbI1/;BbI2 RbI2 jRbI2

obs. 63 287 564

expo 46.6 319.7 547.7

2 = 9.561, d.f.= I, ^p .005

Similarly, the samples collected inshore or on localities near the coast (sample 1 to 37) of young cod do not fit the Hardy-Weimberg law:

RbIl/RbIl RbIl jHbI2 RbI2jRbI2 - - -

- - - -

obs. 150 1051 2633

expo 118.8 1112.0 2603.2

2

=

11.881, doL = I, ^p .005

Despite the restricted area of sampling and the limited number of samples it is convincingly demonstrated that the relative strength of Arctic and coastal cod in the northern Norway and the Barents Sea appear to depend on depth and distance from the shore.

The result coincides ,,.ri th the results of previous studies concerning the distribution of Arctic and coastal cod, such as tagging experiments and determination of the otolith ~JPes (Hylen, 1964, 1967; Sffitersdal, 1956).

- 3 -

The immature stages of the Arctic and the coastal cod forms prefer different environments. The result being another reason to regard the two cod forms as two sinling species.

Hylen, A. 1964

Hylen9 .t.f':J.. 1967

M0ller, D. 1967

:t-wller, D. 1968 a

110l1er, D. 1968 b

Sick, K. 1965

Sa3tersdal, G. 1956

References

"Kysttorskmerkninger 1964". (In Norwegian, English summary~.Fisken Hav. 1964, No.6~17-18.

"B"orsk traalfiske langs Finnmarkskysten i ^OID- raadet 4-6 mil fra grunnlinjenll. (In :t-Tot.twegian English summary). Ibid.? No.lgl-8.

-~

"Red blood cell antigens in cod". Sarsia, 29g413-430.

"Genetic diversity in spawning cod along the Norwegian coast". Hereditas, 60gl-32.

"Studies on genetic diversities in Arctic and coastal cod in NOI1oTegian waters". 84 ^pp., Univ.forl., Oslo.

"Haemoglobin polymorphism of cod in the Bal tic and the Danish Belt Seal!. Hereditas ⁹

54~19-48.

"Resul tater og oppgaver i fiskeriforskningen i nordlige farvann". (In Norwegian).

ForsEning Fiske 1956, No.l~1-23.

Table 1. Date ⁹ locality and number of specimens of, and gear used for collected fry samples.

Sample

No. Date

1 14th Oct.1963 2 4th Oct.1963 3 ^I1 27th Oct. 1964 4 3rd Octo1963 5 ',28th Octo1964 6 ,3rd Oct.1963 7 /28th Oct. 1964 8 15th Oct. 1963 9 15th Oct.1963 10 9th Oct.1963 11 19th Oct.1963 12 8th Oct.1963 13 18th Oct.1963 14 lIst Novo 1964

Locality 0ksfjorden 0ksfjorden 0ksfjorden

Gausvik, Vaagsfjorden Gausvik9 Vaagsfjorden Rolla, Vaagsfjorden Rolla, Vaagsfjorden Eidsfjorden

Eidsfjorden Ulai'gorden Ulsfjorden Allafjorden fl.l tafj orden Varangerfjorden

I No. of specimens

60 65 60 81 73 77 80 22 84 85 67 68 15 77

Gear Shore seine Shrimp trmvl Shrimp trm-rl Shore seine Shore seine Shrimp traitrl Shrimp travrl S'.aore seine shrimp trav.rl Shore seine Shrimp traw'l Shore seine Shrimp tra'Vrl Shrimp trawl

Table 2 • Date ~ locality 8.l').d number of specimei • ..., of ~ and gear used for collected samples of yOt:n1",-.. 'od.

1

Sample

N~.

1 2 3 4

,-

:J 6

7

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 ______________

~~~~-- Loc~li

ty

---J!i~. Oi~;~cir~ns

__

~+=---<k~-=-===-=-l

4th Oct. 1963 ~ksfjorden

I

57

I

Shrimp trawl

I

27th

oct.

1964 ~ksfjorden I 80 Shrimp trmTl 25th Oct. 1965 0ksfjorden 109 Shrimp travl1 3rd Oct. 1966 0ksfjorden 115 Shrimp trawl 3rd Oct. 1963 Gausvik~ Vaagsfjorden 28 Shore seine

Date 26th Octo 1965 Ro11a~ Vaagsfjorden 26 Shrimp trawl 28th Oct. 1965 r1aa1snes9 rlfa1angen 85 Shrimp trawl 30th Sept. 1966 Maalsnes, Ma1angen 97 Shrimp ·braw1 lOth Oct. 1963 TromS0 191 Trap-net 9th Oct. 1963 BIDeivik~ Ulsfjorden 20 Shore seine 7th Oct. 1963 Breivik, Ulsfjorden 156 Shrimp trawl 11th Nov. 1964 Breivik, U18fjorden 115 Shrimp trawl 16th Sept. 1966 Breivik, U1sfjorden 120 Shrimp trawl 29th Oct. 1965 Gr0tnes~ U1sfjorden 59 Shrimp trawl 28th Sept. 1966 Aar0y~ Kvenangen 120 Shrimp trawl 29th s~pt •. l~66 R0d0y, Kvenmlgen 114 Shrimp trawl 8th Oct. 1963 B088kop, Altafjord 156 Shrimp trawl 30 Oct. 1964 Bosekop~ Altafjord 95 Shrimp travl1 30th Oct. 1965 Bosekop, Altafjord 39 Shrimp trawl 19th Sept. 1966 Bosekop, Altafjorcl 120 Shrimp trawl 28th Febro1966 S0r0ya N.71003' E.23°31' 98 Trawl 2ncl Nov. 1965 StoTams0Y, Porsangerfj. 173 Shrimp trawl 16th Narch 1966 st. rrams0Y? Porsengerfj 0 119 Shrimp trawl 20th Sept. 1966 St. Ta!llS0Y? Porsangerfj. 120 Shrimp trawl 27th Sept., 1966 Svaerhol t, Porsangerfj. 118 Shrimp traw"l 6th Nov. 1964 Maar0Y, LakslUfj orcl 96 Shrimp trmv1 5th Nov. 1964 Kjoldneset, Tanaf,jorC! 120 Shrimp traw"1 21th Sept .1966 Kj e1dneset, Tanafj ord 119 Shrimp traw·1 26th Sept .1966 Losvik, Tanafj arc'!. 120 Shrimp trawl 14th March 1963 Tmlasnnget N. 71 0 06'

,E.29°001 115 r:f.1rm11 20th Apr. 1964 T8nasnage-e lif.71°00',Eo29~04' 40 rrrawl 2nd Maro1966 Tanasnagot N.71°01'?E.29~06' 118 Trawl 15th Jan. 1967 Tanasnaget N.700581~E.28~59f 120 Trawl 12th Nov.1965 Makkaur 119 Long line 2nd Nov.1964 V.Jacobselv~ Varr;:angerfj 0 93 Shrimp travT1 continued on next page

..j:::>.

T~ (etd.)

- ---.- -_.

---.-~J Sample No. ~ Date Locality No. of S'peoimens -Gear--

--3"6---,

23rd Sept.1966 --Vad~0~ Varang8rfj~;de~---118 Shrimp-t~:~~ I 37 16th J8.11.1967 Kiberg~ Varangerfjorden 120 Trawl 38 4th r·1arch 1966 Ma1angsgrunnen9N.69°51' 9E.16°42! 97 Trmll 39 21st Novo1964 Malangsgrunnen? ))T.70000' ?E.17°10' 79 Trawl 40 19th Nov.1964 Bear Island N.73°55' ~E.18°15'. 133 Tra,v'rl 41 28th Febr.1964 Nordkapp BaDk N.72°12'~E.24°25' 123 Trawl 42 1st March 1966 Nordkapp B8.1llc N.71~55'9E.25~10' 120 Tra'ltTl 43 20th Apr.1964 Norillcyn N.71014'9 ~.27°55' . 90 Trawl 44 18th Jan. 1967 East Bank N.700161~ E.32°25' 117 Trawl 45 12thrlfar.1963 EastBankN.70~0619 E.33~45' 138 Trawl 46 13thrlfar.1963 SkolpenBankN~70054t9 E~34°00' 80 Tra1lll 47 10th Mar.1963 Skolpen Bank J:lT.70~1019 E.34~501 150 Trawl 48 26th Jan.1967 Sko1pen Bailie N.71~21'9 E.35~31t 120 Trawl 1---_. ---_______ _ ______ _ IJ1 lable 3. The distribution of the haemoglobin patterns~ the frequency of the HbI1 allele (q1)? and the depth of the cod fry samples_o ___

[----1--

HbIl/HbIf---gb!l/HbI,2 -

I I HbI2,mbI2 Total of rare 1 Depth of sample Sample hoiiiO"Zygotes heterozygotes

L

homo zygotes types q in meter

I

---·-37----. _. .---.---_ . 1 4 19 0 .225 2 2 4 22 39 0 .231 200 3 3 14 43 0 .167 200 4 8 19 54 0 .216 2 5 7 32 34 0 .315 2 6 0 15 62 0 .097 300 7 2 10 68 0 .088 240 8 4 11 7 0 .432 2 9 4 36 44 0 .262 250 10 6 29 50 0 .241 2 11 7 28 32 0 ... 313 125 12 9

25

34 0 ·316 2 13

_~----~--J

6 7 0 .333 70

L 14

21 52 1 .175 200 ---~---~-----...,---~ ___ • ___ . _____________ 1

Table 4. The distribu·tion of the haemoglobin patterns? the frequencies of the HbIl allele ---blooo. type E (pI:)? and the o.epth of the samples of young cod. _--. (q1) and the t---c-----.---.---,---.---. ._+-, -

I

HbI1 /HbI1

I

Hb I l/HbI 2 ! HbI 2 /HbI

2

I

Total of rare

I --_._---:-] _ .. ~at,,-+_~omo:ygotes11- ho{e~~got0s __ l1o;:zygotes-+ . ___ t~pes - t-.-~~7 _

2 7 20 48

I 5 1.

216 3 5 31 72 1

I

.188

4

6

33

70 6 .196 5 2 13 13 0 .304 6 1 6 18 1 .154 7 3 20 62 0 .153 8 5 40 52 1 .255 9 19 83 88 1 .317 10 2 7 11 0 .275 11 9 42 105 0 .192 12 4 38 70 3 • 200 13 1 23 96 0 0104 14 4 17 38 0 0 212 15 6 37 76 1 .204 16 1 18 89 6 0088 17 9 61 86 0 .253 18 3 35 57 0 .216 19 1 10 27 1 .154 20 3 45 70 2 .213 21 6 23 69 0 .179 22 6 44 122 1 .162 23 1 32 86 0 .143 24

5

34 79 2 .183 25 1 25 86 6 .114 26

5

10 80 1 0104 27 3 23 92 2 .121 28 4 30 82 3 0160 29 1 22 96 1

-1

0100 . 30

3

26 86

5

0133

I

31 0 9 31 0 .113 32 3 22 89 I 4 .119 _-----_~ __ -_________ __. __________ ....L _________ _

Depth CD! sample pE

J

in meter ---200

---'--1

.385 200

I

.426 200

I

.487 200 2 240 200 110

.269 .4176 .674 .917 .708 .458 .568 .508 ·343 .637 .645 0825 .155 .606 0419 .592 .283 .152 .432 ·310 .263

.233

.164

15 2 115 110 120 175 110 295 70 70 70 70 220 210 230 230 230 220 175 180 310 290 220 220 continued on next page

0'\ I

Table,.,.!... (etd.)

r--- .

I '--l~-l'--

---. --1- 2 1 -2:"----2---' ----.- --- _·---1---·---'

HbI IHbI HbI-/HbI HbI /HbI

I

T I.. 1 f

I I

D I-h f 1

I

-~ ~ -... ---O"va. 0 rare 1 . Op'v 0 samp El

:~p1e ____ hOmO;ygotes heter::ygotes r-- _homo:;ot"" __ 1_- tYP:s ---.1:8 - -. ~3---iIl~::ter-J

34 2 29 87

I

1 .139 .187 215 35 2 31 56 4 .188 .641 200 36 1 26 91 I 0 .11~ .244 230 37 7 39 72 2 .221.368 110 38 1 16 80 0 .093 .208 260 39 5 19 55 0 .184 .575 220 40 3 31 90 9 .139 .101 250 41 2 23 98 0 .110 0048 265 42 1 23 96 0 .104 .112 255 43 3 14 73 0 .111 .097 250 44 5 21 90 1 .132 .068 180 45 1 21 136 2 .072 220 46 1 14 63 2 .100 180 47 0 25 124 1 .083 230 48 1 17 102 0 .079 .100 190 -.::J

Special !IIeeting

lIo. S/r.10ller ^{300 .(~89)}

13°

12°

11°

70°

14°

200 E

• -

c. 100

o GI

o

Figure 1.

• (16)

• (67)

• (202)

• (164)

(77)

~ I I

.I .2 .. 3

q'

Relationship between frequencies of the Hb Il

allele (q1) in samples of 'cod fry and .

sampling depths. Figures' in brackets represent_

the number of specimens.

, - - --- r r -- I ~- -~r -~ - . - - -

•. 139

•. 110 8;104

8.111

• .&79 .1I4~ • .136

.079 8

8.100

~D~ _~~t.vi cl~

.... ~.i1 • .I0~~.I0~0.13_9

?J

^{;0/40 .083}

e.l63

~I

•• 1 3 2 .

8.184~Qp

^8.008

.•. 09~":~2i'2f\t ~.223

A~.~~7.173

^..

204

Vf~··20'J?

8.154 8.304 8.204 .

18° 22° 26°

.188 - . 2 2 1 _ .

8.119 012

30° 34°

Fig'.lre 2. The frequencies of the lib Il allele in the di£fersl1.t sampl ing

localities.

>'

, ' ...

•

o~

•

r:il • Q) t1l

• • I

~.~ .p.p

I

or!

+

0 tOM

•

o et!

.. •

C\J 00

•

0

.

MO

.

'

•

PM

-t-. ~o~

• •

CH M -0+ 0 ~

•

t1l t1l Q)

• •

0 or! .p

0 o

m

• • m

~

•

&~

+

0 0

• •

Q) 'tr1

•

0

• J:l:a

"-tl

•

0 0 Q) Q)

-

g:l:S

0 0

0

.~

0

o~

-.p Q) ~ .,Q?Q) 0 F:.'M MM 0 0 0 et!~ rt) 0

or!-e;" C\J 0 0

(0) Q) • W • lUd 9Q P!~ t:r.l;<-t

73°

72°

71°

7-0°

Special Meeiiing no.8/N011er

• . 101.

84° 18° 22°

e.048

e

.112

26°

e.097

30° 34°

.100

•

Figure A. Relationship- between f~equencies of the Bb Il allele (ql)iJl samples of immature cod and sampling depths.

Legend: Black dots, sample 1-37; -open circle.s, sample 38- to 48; crosses, means of samples, repJ,':esented 'h;" black dots and wh,ich are

surrounded by a line. -

/

Special 1IIeeting ... No.8~11er .

E

.s;:

..

-

^Q. _CD

0

300r

• ~

0 0

0

8

• • • • •

It • • ₊

⁰

•

200~ ₀

• • .. ^•

• • •

(. ^• _{• • •}

1001-

I • +

.- ^•

o

^{~I ____ ~ ____ ~ ____ ~ ____ ~~ ____} L -_ _ _ _ ~ _ _ _ _ ~ _ _ _ _ ~ _ _ _ _ ~

..

.50 .70 .90

pE

Figure

5.

Relationship between frequencies

of'

^thE) blood typeE (pE)

in samples of immature cod and sampling depths. Legend:

see Figure 6. . .

q'

Special :Heeting No.8/l-'f011er

. 30

20

•

• • ..../

~

.101- • •

•

.10

€ill

•• •

• • _•

.30

• "

•

i t / '

•

•

•

pE

"

•

•

.50

•

•

• +

• •

•

.. •

.70 .90

Figure

6.

Relationship be~qeen frequencies of Eh Il allele (ql) and frequencies of the blood type E (pE) in the samples.

Legend: Elack dots, values of the samples; regression line, y = .089 + 179x;

crosses, mean values of the sp~wning groups of Arctic and coastal codo