Møller, Dag

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Cod populations: Preliminary results in the Lofoten area

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This paper not to be cited without prior reference to the author. C.Eo 1965, No .166 International Council for the Exploration of the Sea Gadoid Fish Connittee Cod populations: Preliminary results in the Lofoten area. By Dag Moller Institute of Marine Research~ Bergen. Variations of the annual structure and the external fo~ of the oto-liths among cod was reported by Rollefs8l1. (1933 ).Two DRin types of otoliths could be distinguished, one being tY:;~='_r;::.l for the Arctic cod which lives in the Barents Sea and migrates to t:'18 HOY'1'.T8Gian coast for spawning. The other being representative for cods :,-:c~-=:.:<.!. <:;:1 •. 1 year round in the Norwegian coastal waters. Rollefsen refers to C8:r-·t~'~~~. ':hanges in zone types to alter-~tions in the node of life. During the spring both types of cod s ,;rnear in the spawning areas along the Norwegian coast froQ Hare to FiL.c~~idrk. The FisherBen catch both typ~s of fishes at the same time by the saw~ gear, thuugh the proportion between the types are different in the catchesfrDm the different gears used (HYlen,1964 ). . In order to get IGlow:ledge about the types or groups of cods and their relation, genetic ccntrolled variations have been established in cod. Sick (1961) found haer:lOglC:"i:.'l polynorphisIJ. by agar--gel e1.ectrophoresis and Holler (1965) established the systen o:fcodoni~ant transferrin alleles by a modification of the S8I:-c2 electrophoretic techniq.-ue and. by autoradiography. He also has studied ':::2-J.-::; bi.oodtypes detecting eight different specific anti, f d th I i'- -.. ~()'2) gens 0 co ery rOCY0()S 'J~c.L~or 1 ! /t • During the SpaWl'clng se:i1;30n 1965 five sa"1ples of 90 to 130 individualf? eaqh, were collected i;:-.:. ":;11.9 L.ofoten area. Each fish 1'laS investigated in re";' ga:r:-d to otoli th-, blood--, tJ:<Hlsferrin .... and haeooglobintypes. According to th~, otolith types the sarnp.:Les were separated into two groups of cods, spa,,q-~ ning Arctic cod (skre:i.~ and coastal cod. Then the ge1j-e frBquencieB of the .,' haemoglobin allele HbI ; the transferrin al1eles Tfn , Tf and Tf and the; -'equencies of the bloodtypes A and E were calculated for each group of cods. The results are shovm in the Table.By way of conparison corresponding results of two sa~ples from Bj0rnaya and Skjervoy, caught in the autru~n 1964, with statements more or less representative for the spawning Arctic and coastal cod respectively, are placed at the bottom of the:Table, The frequencies of the skrei groups frnm each sample show to a great ex~ent interdepend!.ent w'ith the frequencies of the sanple from TIjornoya. The frequencies of the coastal cod groups show connection with the fre-quencies in the saople Skjervoy. The averages for the totals of the skrei and coastal cod groups correspond nore with the frequencies of the samples Bjarnoya and Skjervoy respectively than with each other. By means of the otolith types suggested to be formed by the environ-ment, the spawning stock of cod in the Lofoten area can be separated into two groups, the skrei and the coastal cod, which are found to differ in frequencies of genetical controlled che.racters. The spawning in the same area accordingly do not givG rise to iI.~portant exchange of genetic naterial betw'een the two nain populations of cod. References~ Hylen, A, 1964. Coastal cod and skrei in the Lofoten area. FiskDir.Sk:~.>ser.Havunders. 13 (7) : 27 - 55. Maller, D. 1962.SerJlogy of cod in Norwegian waters. Interim report on technique. hC.EoS., C.l~. 1962, 38: 1 - 2 Moller, D. 1965. Seruo transferrins in cod. I.C.E.S., c.}~. 1265 Rollefsen, G. 1933. The otoliths of the cod. FiskDir.Skr.ser.Havunders. 4(3) ! 1 - 14 Sick, Ko 1961 I-Iea'::1og1obin ploynorphism in fishes. Nature. Land. 192! 894 - 89~. _'r.'~' ___ = - ___ --..-.r-r.-__ ... • ----._~, ,~ ___ _ , daml>les:froin the Lofoten area during the spawning seDBon 19')5 with the individuals divided 4nto groups according to 1ho o~olitl3 types with rolDtive frequencies of the haenoglobin gene HbI , the _t:rans~~~:ri~_~~_n_es __ '!'!_J __ ~! __ L~~_~l_~ __ ~h_e __ ~~~~<:l __ ~xp~_~_-:.~a~_~ __ !,g~a9J1_B:£g~ __ . ___________ . _____________ . ___ ._. Dc: te, .of s amp:l':t:n t;j Ganple Locality --------..;.....--------17.2.,65 Hola otolith type' Group ! N-1 Genn ~requ~ncie . Blood types frequencies o. lib"'" A '. B C A T."\ .i.. 'Tf' Tt' . Tf i!t --~, .---...----~-. ...------.~-r-----~.,.---------"----I . . , . 65 io.1172'O.1154. 0.130Si' 0.6462 I : I I 62 ;°.2981 0.123~ 0.13931 0.6639, i : I I . I I ' 0.5231 005294 0.7222 0.2308 0.6471 540.091+30.09321 0.2119 1, 0.686l~1 . I , 89 0.2778 0. 0722i o. 1 -3331. 0.6722; ;25.2 •6 5 Hola 007361 0.4074 0.5972 ( 27.2. u5 Hola 2.3.65 Sorvagen skrei coastal cod I' 40 0.16251°.0952 0.2381\ 0.6548i , I 49 10.25581 0.090~ 0.1500 o Q 7600! 801°.05631°.11590.15461 0.6975 40 10.212510.0500 0.22501 0;07125 I Risvoor I skrei I 59 10.086210.1500' 0.1 ~647 0.6$33:' ________ ~~ 39 jO.217910.08~T~~410 0.7308 . I skrei I 298 1°.096610.11570.15621' 0.675811 5.3065 TotaJ. I ,f.l.veratse! 1 I ~ i' 1. __ .---.--------------!--.-~<?~~ta-~<?oct.---t--~7-~-+2_.~3607: 0._08~9 _9~87+-_ 006997:: 12x.. flay 6·£ gonppr:l.:.so!]L ! I i ' I' ,; 19.11.h4, Bjornoya I skrei I to.1391io.1554,0.1588:, 0.638 5: 0.4750 0,7209 0.4750 0.6750 002750 0.744 2 000625 0.6000 0.4915 f 0.1186 ,-_. -~~~-t--0. 6153 ~ ::;~-i--:: ~~i~--26.10.,~lJ.· Skjervoy: coastal cod ! !0.3878l0.0523 0.1J73:, 0.7974:: 007679 I 0.9554 _ .. _ .. _--_. ._-----------_._---_ .. -.---------------.-.. --.--.---.. -~------~.-------.-------+---------.---.----.-----.. /" ... 

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Cod populations: Preliminary results in the Lofoten area

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