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!his ·pnE~~. to be ci ted,.vithout,prior rci'erence to the nutho:z:' ..

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Interna tional C.:>Uncil' o'f tiwExploration 01" thc Sen: .

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'; C.u. ,19791L: J 4Eiologicnl OccU4ogrnphy

., ··ColT'..mittee ..,. ." ~

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. Investlgatiolin on 'Krill Euphausiasuperba·'DAi'A .. , off SouthOrk.l10Ys andSouth.Hhct lands in. 1979 ' ,

,­i

Summa,r,l .'

by·,,· ....: .., • i'

. C•. Gllbach

Iust i tu te' tor Deep Ses' Flah'eries' nndFishProcessin€f ROß tock', . 'Ge.t'mt.lnDClllocr~tic Rcpublic

' ..., ... .. {

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'Concentrations of krill have bcen·inv'~ßtigatednorth cf Sou'thOrknoyo und north of King George Ialand. 'Kl'ill shoa lo with poorlydevcloped gonade. showing' a slg.niflcant "diurnal,vort~cCll migr~tionuo weIl os an evident. diurnal l'hythm,·1nfeeding were found on' thcshelt north of,King :George IBland~ Krill of'other ahoalo u.ndcrinveotigation ohaweda more developcd maturity .stlls·e. 1hcof,} oho'1lo:were· standing w1thillthe.upperJOO m.1I0· signlficant vOl.'ticalmlgrotionwos observed.Feedihg .occurredatnight as woll 00 utduy-time. " , . . .

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In troduct ion .., 'j I

BeoideshYdronc'~usti'o, aboorvut:tons \Qhich had baen' conductcd durin'g:",' I

commerolul fiahery t~rom cai-ly in' February .ta .tho end cf March 1979>·opecial reoeoroh, progranlffiCSWOl:'O c'arried out on tho biology cf' .:krill und onfiahery, teohnology 'aboard' aommercinl flE1her.y veoocls ,,:',"chnrtcrcd rar th10 purposc,on· spec1ally~elected otutions off South'iOrkncys end Sou th Shot lands.' .' ~ . ~ .' '. ".' , , '.

Thio paper rciprcet'm tfl' tno 'ob'tairicd'l'EH:lulta. Oll '. biology. of" krill., '

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he vessels w" € 'i i ped ,"t'.. :".1 r ·.,c ..J (.i.'O' 331,fre~uency 31 c an RAG 432, f cq ency~ large pelagic fisn lclt with al eolnr r p Ul the fore n.tacd a net cone wi h 16Q~ m shes aDe ~esh w~at s of v~ t8 30 LlO 'was operate as fisning gear aboar tue Sl.<pe boar-d t1:1tender tra ler a large pelagic fOsh et with rope bri les in thef'ore.net and a net cone with 19 0 esces an m~sr 'dths of 4 '-J

to 20 ~ was operated. Witn coth nete a ~o ir e 4 pJ al encendith an inlet of 20 and 11 respective y 20 ar.d 16 ~ nad been

applied as aft gear.

Following i.nve tigations were C ried Ollt:Hydroacoustic observation, length measurelLent, detc:-l:.ination ofsex, maturity stage and alimentary tract filling.Length measurement was carried out fram the top • t:le rostrum 0the end of +he telson.The maturity stage was det r~in d by using t~e sc le of Ivancv andthe alimentsz7 tract filling by u ing sca le f .. IR, C'rdyniaNansen- sampl rs ith reversing thermomenters na e ueen a plicd fordeterminating temperature in dif er_nt water leptnc •

Results

Occurrence or krill was found north of South Georgia, north ofSouth Orkneys as weIl as above the deep sea area and on the slopeand around tue group of islands within an area Irom King GeorgeIsl&nd 1;0 Livingstone Island (South" hetlands). Herewith t~e ractmust be co eid red, that probably onl relativ .y oneentratedkrill shoale re found by using an echosoundel 31 kc, these couldbe relatively eIl de~ected even 'Ileen they were ~t n ng' de tUeup to 300 m. On the other hand the applied ry ro coustic eql ipmentfor detecting krill shoals standing beneath t e ur 'ace proved notto be ade uate because of interferences deve oping in his area.In the folIo 'i.ng resul ts are represented t VJhic'l . t'e obtainedduring special research operations off South Or' ney nnd northcf King George Island.

So rkneys

In -gtiga.ions have ceen carried ou north of u h rkneys onsi ions between 44°08' - 44 0 52"1 and 59°10' - 5,049 froI:l 7

-eh1' r 015 P bru6t'J' 1979 • .rne 'ater de~th D ..n~· arf'a wascere t an 20 0 III 1'1:.e tota DW'lber of haulo :tS 5.'I'he stock found \'1 i tnin thls rl::öio consis t "~d l.t 1y " ddll1 t krill.? gure 2 ~. 0 'Jß I ngth distributton, "table 1 G••owa h'" rcsuHs onI:1a tur ty s a e an alimentary truct fillin •

- ) -Tilt: propol·tiol 01' f'GnliJles wi th 61 to 70 per cent was greater than .that of mal s (18 to ;8 per cent)o The proportion of 'animals of

• \.11ich ""ex could not be determined was 1-2 per cent.Tile .ülc:turity staGe was near 2 respectively ) but in most cases near). '0 females with eggs bllt spermatophores were found'wit 58 to 78per cent of fe ales. .

The alimentary tract filling was 1 to 5. Only with single animalsthe aliruentary tro.,t Vias empty. No relation to any day-time couldbe det ~rmlned. JI;O diurllal vertical migration was observed as weIl.B~t refarring to this fact it i$ necessary to indicate that thekrill was standing in a depth U;pto 70 m and that the applied soun­dlilg technology for detecting krill in this depth range proved notto be adequate. Significantly catches at day-time were evidentlybigger than at night. .In the period from 05 a.m. to 08 p.m. the catch was 1-) t P rtrawling hour, during ,hhe period from 08 p.m. to 05 a.In. it wasless than 1 t per trawling hour as a rule and dropped partiallyt 0 0 ( F ig • 6).'

_There was n.o exact estimation possible,whether 8hoals di.ssolved"at night or whether there was amigration within the surface l'yer.

The le st <1 pth of fishery was about 20 m. Therefore the fact cannotbe excluded that ·the main part of krill was standing above 20 m. atnight.

King George Island

Even bef'ore starting the krill research programme indicatiOl1s ofkrill have been observed above the shelf north of King G orge Island,whereby signiflcant diurnal vertical migration was found. At day­time these indications were at the bottom in depths ranging from190-)00 m, Ln the evening they moved to the surface (about 09 p.m.).und removed to thA bottom at dawn (about 05 - 06 a.m.).

TheAS indigations have been fisged systemotically on positionsbetween 58 55' - 570 55' Vi Bnd 61 43' - 61 0 50' S on 8 and 9 March •

•6 su cessful haule were investigated, ) of these at the bottomat doy-time end J at thc surface where by at dawn with one haulthe not was lowerad together with the descenting krillIn each CBse ~hen indications were observed the net soun erregiatratod entries as weIl. On the same position a comparativehoul at. th ';) f.3Ul'f'äCEJ durinrl da;y t lme obtained no krill.J.1eble 1 shows the l't:!. ultf:1 on roaturity stage and alimelltary traetfilliIlg ObvioLlsly feed~ng oc~urs maillly at nighti. During day-time7')-9'1 pOl" ee t of the 'mimals sho\'Jed ernpty alimentary tracts aslu,.:'ifl.g tho hLJw's of nigl t mo'ce thon 70 per cent had thair alir en­t'lry ~r.' ctti fi.lJn(l at :\ degrEle of 4 .to 5•.:'l .... Ul' 3 C1, h Vr.' _~onts tno ] cLgth distribution. There 18 a H'Lgnifi­C' nt d' i'tt:f'~.nce in Jength di tribution between males and females.'1ul)10 i fJL10 ":,J t J~~i; Lhc Dtock belS a grent number of irr..nmture indivi­dl EI L. CI Ot. ly 2 (I }Cr CGj,1 t of fe J a IOD conta ined spermatopllores 0

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, OOnOOrtl~lß tho dirootinn or vQ~tioolm18rntiott w1thin 24 houro,thol:'o in Ilcol·tu~.i\,oonJ.'ol'mi~ywith. ObOC1'vll'tionn' by r.lOnU (197G). 'In non tl'UOt 'Lu itiVCJO t ißU tio1l0 ~l;Y X.1011R •. who 'founa j uv onilo kr~.ll

,; with' lIfl t1Vl~l'nBo ltJn[)th of' :;0 m.m' our invoot1GQtod.l~ri11 wno 0100, flot OOlrll11ot~1.v fllU LUl',OU buttho, r.lUin lonuth ronßo' wau' 39-52. mm.

An MOnn tJ!1U n100 othol' nu thortJ Cl')AV!!OV' 1~69. 19'(11')' d~"Ol'ibo n,,vortiool rn1nr'u t ion vd thin ,tho iUPIW1'1 100 'rn. ,kl'fl1, ,wo' ObOC1'vod "i/CUt1tundinß ~.11 ,0 dUf)'LhJof 0 - 100 Dl'ut ni[tht und,nbovo ftho bottor.l

\ in. 0 tlopth 0r:W'(C)," JOO'ln ~t cloy timo, ',' " I'" ': '~' ,, " ~'h() lo\v tcmpurutu.ro Cup', to ... 0.0°0, FiU_ 5) in doptho 01' Inoro thon

100 111 \'/00 'no bUl'.l'iOl' 'to tl1Ul'!1l11 vq:~i;Lonl' miurotion. " , " "Irt OOl1t1~cjut to 'oboorvnt1ono by UOnR',\'ihioh ohoviocl ·tho t b.'1il' 'movon ': ;':uanin npwtlrdtl uoro,li O :t t WeH', Cll\i to .llnht OUt", obcorvn t~.ono 0110\'10<1.. .thut·tho:kvl11 romulnod' abovotho bottom durine tho wholo po~iod

'I. f'l'otn 06 u.lt1' tU,,21 p.M. Ac ,MOHH ot)uld not dCl'torm1no.ony rolotion ," . bö'~wou.n· foodit1ß oud' vU1"tiC'lul mlß1"nt1on, in OUl" coo<) th1::l rolntiou ~

. Wan qu1.to oicnificl1nt~· OOilOornlnß Huf rolation uatwoon vOl'~;;l,onludßt'n t ion, und foodinn OUl10l'vot lona aal'OO .with l'OflUl to o1:1)AVI.OV ,

" , (19G9) ~'Ihö doto~.'nd.,l1od '. thai;; foouina oooul'J:'od VI hau tho J:1'111 otcndo, • in tho' UPllCU;lwotop loyoro. Dachton PAVLOV, ':f:ouncl, thut in moct, oanoo ', tho ot otnnoho ,oi' kt'ill,worG ompt:;. whon ooußht 'in u dopth or 100 ,"

'fig~~tö~fitnl~ 1~~g) m~loo' {i~oorib~O 'n d1Ul'twl' m1ßr~~10n'b~~bVHJOn'doPth', '" lio.l1goo f.rotnO .. 100:'m ot 'n1e11't,'ond üopth rOllßoo ,i'l'om :300·, 4S0 m ' ,, u t .doy..t imo • Docidoo nhoolo, mon t io,nned abovo, 1nüioo 'b j,Ol1o' of 1t%'111" : ..

, hova' boon i'o und1n ti thct'" poni t iOhO ,'0 t 'tho 0Bl'fa 00,01'0 I{1ns QOO,t'ßo ,,"Inland 0100 atüoy.. timo.:On thc pooit1cn 61,30'8. ,58 ,15'W,OllO!1' n 'ohoal liod lloon i'iohod nbove 0 \'Iotortlopth cf, 7,00 '~',1000 m (dopth ,ci' fiahot'y -.40 :"","50 m) ,on 11 March. Bl1 t thoro \'IUEl' no '101'1301' ahatl 1',

. 1'OWld' \'/hich.cOlUd hove boen' i'1ohod ovcru 'longor poriod. , " .,.' , ''1~hore \~H:lS 0'" f l1r.tÜci OÖ011'ch,ror'krif1

1ön' tho ,'olope 'w1 thou't ~1nd ine .'c.: ';'

OilY lnd1catboIlO on 19,Mnroh...About, 4, 0 p.m.otl'owl"wog EJhootod ot " .'~', '',," ,po,oitiö,uG1 A8 !,S .,' 59 14' Wand .\'Job towod ',.w:1:th' O,OL1It"tJo 75 , 'bonol'lt!(', ',: '-',"';,,/ ,~;'; ,, " ',tho ourfuoo" (do,pth 30..35 m).i'or, two; houro [md 0.40 ll1!tiutoJJ' TlüF, ',":,: .:'; ;', ,~', ' " ' : ' reslll t, '.wan'Ob,Oii,t,; ,1 ",':t>of" lC11111.",,, In '.-oom,P,ar1lJOn,W,:I.th,', taoto:, C,Ol'X'10d,,'.' :~\",',:.', :',':" ",'

,," ",,' OU~ on,a ond' 9,Mo:rcl11al"uor,opooimon : (;Flig. 'J~ c) ,dom1natod,., ThicJ,',':,'.'.,:"',,:',,', "':' foctwt;\apartioulorly:oigrtificant',with ,fonloleao, >,,.:' "l,' ';:,'.,,', ,~:.:.J:, ,';~' ..... ',The':.'kl"ii1 ,üi' qu~~ t :ton:: eher/Gd:, aI';m'ore ~d:ev el~p~(i 'mn,~ lU~:l.ty "ritoG~ ;,: .,.",. :"',', i :<:"/: ",\':,l

'::;"",' (Tnble:, 1)., No ,i'eml.l1oo 'with',oggs woro ,found.,:In:oontruot,>to, kl'ill:: ',:': .:, ,,;,), :;,I', with 9 'lOW,e"r. 'mn,'tur,'1 ty:ot,' aBO fOO~i,' n,S" OC?U"red'"pt'"tlH3' 'Dur,,~no,' ~. ,OlSO",.,::,,!:,",,;'::':" :'::~:,

J;during,'dnyhouro'(Table:'1}.'Thio'kr.il1,o~().ck: rosomblod that, OllO, i'·,".'c,,: ,'. ~":wh1ch .. had; been 0:'caught,no!·th ,01'. South:,Orknoys,nbov 0 .':tho ,deen· sen" '" ,.:~:~:::~,:::-,:"":",,aren, corlCoridneFlength'" incitur1tYstoge.;' ahdbehaviour.• ':. '::>. :,.',,:, I,,"

r:':;::;;:)"'" 3'~;;:;N:··.';}C;~ ···\~:··· , .' ". : ': '.' :'.' .. ,.. ' .' ~. ~.

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Refel'ences

.HOLZLÖHNER. S., 19'{fl..\ \

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IVANOV, B.G~ 1970

MOHR, H.19'76

~PAVLOV,V. Ya.1969

'. On the. biology cf the Antarctic krillEuphausia superbaMar~ Biol. 7 (4): 340'~ 351·

Tageszeitlieh bedirigte Rhythmik im'Verhalten von halbwUchsigem Krill, (Euphalisia superba)" . .'. .Inform. Fischwirtseh. t Hamburg n (4/5):

. 132 ..; 134

The,feeding'of krill'and'somB featuresof its behaviour' (Russ.)·Trudy 'VNIRO &2: 207 - 222

PAVLOV, v. Ya.,1974

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On 'the nature cf the relationshipbetwc~n the feedin~ habits and certainpeculiarities of -the beh,aviour inEuphausia superba Dana (Russ.)Trudy VNIRO~ : ,104,,:,,116

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T&ble 1:• e

Re~l--t8 o~ determination of mat~ity stage and alimentary tract fiJJj=ng (in per cent)

,

--Ai - d --'-

]iishing Maturtty Sex 'Sne~to-}ll1.nerrtary:Position Date Time D~lth depth Catch stage not ,n- oxes . ;!"ac~ n

(m (m) (t) LIes Females dete.r-{p.c. o"f ... ill:J.ngmined ~emales)

... 2 3 4 52 J '2 3

3-0rkney I. , 8.2. 11,40:"13,17 )1000 20-25 7 69 22 2 55440Ö8'-440~2'W 11'.2. 02,35-04,15 >1000 20-40 1 15 2':; 2 59 1 58 8 45 23 21 3590 10'-59049'S

"09,20-11 ,20- >1000' ,20-30 5 16 20 0 64- 0 78 3 55 31 115,00-17 ,45 ~1000

-, 20-)0 6 22 z- 68 2 4 37-25 26 8

12.2. 05" 10-08,00 ,>100<l 25-)0 5 ·10 22 ° 68 0 59 40 16 32 12

King George I. 8.3. 11,00-13,30 295-300 280-290 3 38 22 1) 19 8 71 22 .,. 3570 55"w-58055 ' ,

, 61 043' ~61050'S 21,40-00,15 290-300 30-40 0,15 43 6 24 13 14 5 5 20 54 21

9.3. 04,30-06,30 290-300 30-250 3 45 1 34 14 '6 0 8 ~9 4A. 29 10C0~Oa-09,15 290-295 25~260 2 37 1 41 10 11 2 79 16 3 2 10015.55-16.50 . ,28'5-295 280-290 2 50 2 30 Q 9 5 92 6 '"' 100.J c.20,50-22,?' 280-300 30-40 3 59 5 18 7 11 ,4 1 10 19 42 28 10J

King George I. 11.3. 11,15-12a-20 700-1000 40-60 12 38 2 47 1 4 13 21 39 27 10061 °30 'S '

° ' -I58 15 'l1~

61 029'S",)8008'\V61°48'5,590 14'Vl- 12.3. '16; 1Ch:ts,,50 350-370 30-35 1 35 18 438 5' 48 12 21 38 29 10( ,

61046'~,58°56 'VI

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-60'

, l

Fig.1 Positions of krill researchprogramme

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Ag.2

South Orkney I.08.02.-12.02.1979

55 mmLcngth

50

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1---..... Moles

I-----t Femoles

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--c b: 08. - 09.03.1979cu(.J

(IJ night / surfoc~- ~

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c: 11. 12.03.1979

doy time I surface

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200

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. Temperoture2 oe

• Fi g. 4 Woter temperoture off South Orkney I. .

Position; 59°23'S,44°50"'W (13.02.1979)

~--- - Position: 59°10'5, 43°30'W (14.02.1979)

.,

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100

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300

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Fig.5 Woter ten1perature off King George I.

I' Position: 61°'44'5 58 0 33'W'(09.03.1979}. ,1--- -- Position:61°30i5,58°18'W(11. 03.1979)

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Fig.6 Cotches of kril' off South Orkriey I.

Position: 44 0 08' -44°52'W59 0 10' -59 0 49' 5

roi()Q)'0600120Ö 18 00 00°°06°012°0 18 00 0000 06°0 12°0 '18 00 bOoo Q50012°Ö 1800 00° 0 (1' 60 12°0 18°0 OOOOtime'1.0'l. 12.02. 13:02-. 14.02. 15.02.1979 date

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