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ICES
C.M. 1992jG:79 - Demersal Fish Comnlittee,
Ref. L - Biological Oceanography Cttee
The effects of matemaI statUS of ArCto:'N0rWegiäri. cod on egg quality ~d
vitality of earty larvae. It. PreliritinarY resuIts of the exPeriment iri 1992
P. Solemdait i 0. Bergh 2 i R.N. Finn3 , H.J; Fyhri3, o. Grahl-Ni~lsen4, o. HOßUI"let,
O.S. Kjesbu1 , E. Kj0rsvikS, 1; Opstad2 arid A.B. Skiftesvik2
IIistfttite of Marine Research, Bergen, NOIWay. _
2 Institute of Marine Research, Austevoll Aquaculture Research Station,
NOIWay' _
. .'.
_.3 Zoological Laooratoryi University ofBergen; Nonvay
4 Departrilent of Chemistry,UriiversitY. of Bergen, Norway
5 Departrnent of Aquaculture, University of Trondheim, Norway
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Abstract
The stage of spawning of females of the Arcto-Norwegian cod caught dtiring
peak spawriing in Lofoten had a profourid effect on several v'ital parameters of
the eggs and larvae. SignifiCant negative correlations ,were demonstrated
between stage ofspaWning and size of eggs arid lai-vae arid total content of no~­
protein amino compmmds (NPS). Reduced larval activitywas recorded in
groups from_ cod .females at the end of. spawning. Investigations. on the
bacteriological status and the fatty acid profiles of the eggsare also incltided. The
resülts are proposed in order to demonstrate a recnii~ent mechariism and are
discussed in this connection.
I; intröd~ction
The recrultIrient mechanisms on the eariy larval stages are caused by two
processes working simultaneously:
annual clegree of syn~hr~riizatiori of the earir fish iarvae to it's
fo()d. This, idea was first put fOIWard by Hjert (1914). .
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2) The maternaleffects on egg .qual itY. arid the vitaIityof eal-ly larvae resultirig
from female siZe, conditi()~ and the stage of spaWning. The piorieer irivestigalions on the matemal effect were carried out by SOviet investigators (see Nikolskii 1962a).
1> TIlevaried
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2
Nikolskii (l962b) tried. to put the two processes together: 'The Detter the supply
both of yolk, and of external food for the fry cit this stage, the higher the sirrvival
rate".Temperature is the factor directing both processes. Since temperature
variations are a large scale phenomenon, covering both spawning and nUfsery
areas of the Arcto-Norwegian cod, a inodel of an adaptive larval production has
been j:>tit forward (Ellertseri & SolerridaI 1990).
The preserit results aim to meastire the'effect of the stage of spawning o~ 'the egg
quaIity and the vitality of the early lcirvae.
In general tWo types of studies were carriecl out to solve this probiein:
1) Comparative experiInents ori survival, feeding, growth and behaviour of
larval groups from females of different stage of spawning (Solemdal
1991~
.
·2)·From basic kr\owledge of the chemicaI com!>onents (amIno and fally acids),
larval groups from fema~es of different stage of spawning can be evaluated.
et al.,
•
The present. paper tries to some extent to combine these types of' st'udies,
restricting the experiments to the pedod from hatching to the end of larval
endogenous energy resomces.
.
Iri addition to the stage 'of spaWning, both slze arid cond.Üion of the cod femaIe
are iric1uded in the, analysis. The next step will be to collect a homogenotis
material accordingto stage of spawning to analyze effect of female size and
condition spedfically.
11. Material ~d Methöds
Th~ data on the spaWning cod. fern ai es useci in theegg arid larvae experiments
are described in Table 1 taken from SolemdaI et al. (1992)..'
.
Egg parameters
Egg diameter from 50 eggs were measured miuiually according to Kjesbu (l989).
Egg cirY weight was calculated on the basis of 50 eggs dried for at least 48 hours at
70°C. Weighing was performed with a Cahri rriicrobal.ance..
Egg stress experiment
The eggs were stressed by bubbling air through ihe water from day 3to day '1 äfter
fertilization. About 500 eggs \\.'ere incubated in tariks of 6 1 UV-sterilized and .
filtered (0.2 ~) sea waterwith a, temperature of.· 5°Cand a salinit}r of 32%0. The
air .was filteredthrough a 0.22 Millipore filter aIld bubbled into the tanks cit ,a rate
of 1.5 1 rriiri-l. Dead eggs were iemoved and counted every day.'
.
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Respiratory sttidies Qlzd analysis
0/ non';'protein nitrogen
For respiratorystu~ies and analysis of nori-proteinnitrogen, groups of eggs from
the variO'is batChes,were iricubated in therrnostated glass aquaria at 5 ± 0.05 °C
arid a sälinity of 34.5 %0. No stirring or aeration was applied.
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SampIes of 50 pooled eggs (four paralIeIs) were extracted in 6% tdchloro-acetic
acid, and the supernatarit analysed for total content of non-protein amino
coinpounds (NPS) by the riinhydrin procedure of Moore arid Stein (1948) using
nor-Ieudne as the reference" standard. ,The,embr}ronic öxygen ,consumption and
ammonia excretion were determined by closed respirometry. and polarographic
measurements of ,oxygen tension in test (5 paralleIs) arid blank (4 paralleIs)
respirometers as descrihed by. Finn et eil. (1991). Aritmonia was determined by the
salicylate-hypochlorite method of Bower and Holm';'Hariseri (1980).
-Larval parameters
Dry weight
Before drying, ten hirvae were rinsed twice in distilled water. Drylrig and
weighing procedure äs for eggs.
Developmental stages
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The early laivae were staged according to the system. by Fossum (1986).
Beltaviourial studles
At day i after hätching (50 % hatching refers to day 0), 20 larvae, from each
experimental group were transferred to observation chambers holdinglOO ml
filte~ed (0.2 Jlm), 34 %0 sea water. The temperature ,was 5°C arid the laryae were ,
kept in darkriess~ The activity level was measured by means of an ulti'asm.in4
system (Scanner 450, linear array scanner). A 7.5 MHz transducer was placed at
the top of the observation chamber in suCh away that theplane, of registration
made a seclion of the water column from the top to ,baUom. The ultrasoriic
registrations were video taped; The riumber of swimrriirig larvae through the
ultrasonic plane per unitwas defined as the activity level. For each larval group,
the meaSuring of the larval activitywas' conduch'?d [or one hour in darkness and
for one hom in light (30 lux) in day 3 arid 6.
Bacieriological studies
The eggs were washed three tiines in autoc1aved 25%0 sea water (SSW) and
homogenized in an autoclaved homogenizer. From a dilution series in SSW"the
homogenate was plated onto petd, dishes ,Witb Difco 2216 Marine Broth (Difco,
Detroit, USA) with 15 % agar (MBA) and Tryptone Citrate BileSalt agar (TCBS)
(Oxoid, Basingstoke, U.K;).Mter an incuoation period of 14 days at IDoe, the
ilillnber' of.colonY-fonning units (CFU) were assessed on both media. 32 isolates
from the MBA plates of each group were raridoinly chos~n as representatives for
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the composition of the adherent microflora, and were sUbjects to pheriotypic~l
characterization.Thetests perforrned were: Grarristainirig (Bacto Gram stain set,
Difco, Detroit, U.S.A.), oXidase (API 7046, Bio Merieux, France), catalase (rrieasured with 3% H202) and growth ori TCBS agar. In addition~ each strairi was
mcrphologically examined by a Nikon microscope operated with phase contrast
at,.~OO or 1200X. Thri strains were regarded rads er cocd. Further studies are in
progress.
Fauy acid studies
.
. , . .'
' . . , '.
....
..
Ten eggs from 15 cod were analysed separately by methanolysis foUowed by gas
chromatography of the resillting methyl esters according to thri Iriethod described
by Ulvund & Grahl-Nielseri (1988).
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Egg stTe~s expenments
.
In Fig. 7 the results from, the egg, stress· experiment
is plotted against stage of
spaWning ofthe cod females. Relatively high egg mortality is fciund in the very
begiririing and end of spa~ing, while lower egg mortality is noticed iri the early
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5
middle part of the spaWning period~
Respirätory siudies and analysis ofnoti.;.protein nitrogen ..... . .
The egg eontent of soluble non.;.proteiri amino, eompounds (NPS), eorrelated
riegatively with the stage of spaWning (Fig. 8). Mostly, the NPS represent freely
dissolved aininö acids.
Anunorua excretion but riot oxygen uptake ofthe eggs ,at day 11 after fertilisation
eorrelated with the stage of spawning. Taking the ratio between the ain~onia
pröduetion to, the oxygeri eonsumption the nitrogen quotient (NQ) is obtained
(Griaiger 1983). The NQ is a measure of the proportioneil use of amino acids in
the aerobic energy dissipation of the eodembryo. Wheri the energy dissipation is
fuHy b~sed· on amino acid catabolism, the NQ equals .0.27 while a strict
earbohydrate orlipidcatabolismresults in
NQ of zero. In the present.studY,the
NQ values for the cod embryos on day 11 after fertilisation, ranged between 0.17
arid 0.12, arid ci negative eorrehition existed between the NQ and the spawning
···status,of the mother fish (Fig. 9).
an
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Behaviouriai studies
,
II\ Fig. 10 the activity ofthe eod larvae in one hour ,of darkness arid in one hour
of light at day 3 and 6 after hatching are shown. Development of activity from
day 3,to day 6 are älso shoWn irithefigure. These values resillt from subtracting
the total aetivitf at day 3 from the total aetivitf at day6. ThuS, a value below zero
indicates a decrea8e in aetivity from day 3 to day 6. The larval groups are sorted·
after the stage of spawning of the eod ,females, with stage, 1 first. The larval
groups from the latest stage ofspawrnng show a decrease iri activity from day 3 to
day6 after hatehing, in other words from before to after the point where the
larvae eire able to start feed.
BaCtenological studies
,
. , "
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The number of eolony-forrning units ,o~ ,the MBA and TCBS media, arid. the
results from the phenotypical eharacterization are given iri Table 2. Practieally all
isolates were Gram negative, arid most were rod-shaped. However, same of the
tested parameters showed high ,variation among the different egg groups.
Whereas the assessed mimber of CFU on TCBS. agar was elose to, or, equal to zero
in most of the groups, group 4864 had 3.5·103 CFU egg-1 , 43 times higher than the
seeond 1,tighest !tumber. This grotip alsoshowed atypical results regarding the
oxidase test, as only one of the isolated strains were oxidase positive. Group 4855
and 4973 also had relatively, high nümbers of oxidase negative tests (33% and
30%, respeetively) whereas all other groups weredormnated by oxidase positive
strains. Ariother. fish not inc1uded in Table ,I had 35% catalase negative strains,
whereas all other groups were dominated cy eatalase positive bacteria. The
frequency of isolates that eould grow on TCBS agarvaried from 31 % to 90 %, and
1 on the same
apparently no eovaI'iation with the assessed number of CFUegg,
agar.
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FattiJ acid studies
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Table 3 shows the eomposition of fatty acids cf eggs from the investigated eod
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6
females. A prlncipal component plot of the relative, values of the fatty acids. in
the eggs from the investigated cod fem~l1es is shown in Fig.ll, arid in Fig.12 a
similar plot of the absolute amounts of the fattY acids are shoWn.
IV. Disctission
Egg size is to a iarge extent, a species characteris tie, btit is found to varY both Wi th
spawning time (Hierristra 1962; Kjesbu 1989) arid femaIe size (Zastiow, et al. 1989;
Budcley ef al.1991a,b). For cod; a batch spaWner, it is obViotis that the stage of
spawnirig is the parameter responsi,ble for most of the egg size variation, the
effect of female size being coIripletely masked in the preserit material. Few
atithors have taken the stage of spawning into consideration when investigating
matemal effects on eggs and larvae. However, Hislop (1988) used a. six point
-scale .based on visual, external inspection of the gonad. He selected haddock
females iri early stages of spa~ing to study the maternal effects.~anyfisheries
laboratories ,use similar methods, for staging spawriing,' büt laboratoi-y
experiments' häve proved them to be unieliable (Kjesbu, unpublished data).
Buckley Ci al~ (1991,b) investigated the combined effect of spaWning time arid
female size on egg siZe in Pseudopleuronectes americanus. These parameters
amotinted to 61 % of the total variabilit}'in egg size. A gem;!ral ;rriethod fcr
describing the stage of spaWnirig in this species was riot developed, but bateh
spawning was described.
'rite results on mortality of stressed eggs from eod femaies, in different stages of
spawning (Fig7) fit weIl with tne results given by KjesDu ef al. ,,(1991) ,
demonStrating a eyde of protein mobilization dtiring the spawning of eod. The
spawning stage showing lowest egg mortality eorrE!sponds to the period of
mrodmum iIulux of yolk protein; The same cyde applies also for the production
of chorion material (Kjesbu ef at 1992), indicating a tougher chorion to stress in
the same penod.
Free amino acids are tYpicaIly found iri high anlounts in marine ,fish eggs at
spaWning, and have been implicated as an irriportarit energy substrate ,during
embryogenesis of marine fishes (Fyhri 1990). In a studj, of sueeessive egg batches
of captive Atlantic,cod, the egg content of free amino acids was found,to decrease
during thespawning season (MArst,,1 el,al. 1992). The present egg data for cod
caught dUrlng spawnirig in the oeean agree with that finding.
The bacterioiogical tests showed large' differene~s amorig groups in the
freqiiendes of positive scores. This ,demonstIites that the composition of tne
adherent microflora, vaded among the groups. No systematic differenees with
respect to the maternäI fishwere, howeyer, detected. .
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The analytical method used on the fat in the eggs does not discriIninate betweeri
the different lipid classes, e.g., triglycerides, phospholipids rind free fatty acids.
The results eXpress the total faUy acids in the cod eggs. The faUy acids iri the eggs
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are domiriated by the saturated acid 16:0, the monounsaturated acid 18:1n9 and
the two polyunsatuI:ated acids 20:5n3 arid 22:6n3, (Table 3). Thc ,eomposilion
found h\ the preserit investigationeorresporids closely to those foimd in eod eggs
eollected in Lofoten in 1985 by KlUrigS0yr et al. (1989). The relative amounts of
the fallY,acids, and the total amount of fatty acids, differed ,among the eod
females. By performing a multivariate principal component analysis of the data,
the differenees in all fatty acids. are considered siinultaneously. Differenees
amorig the 15 rod are seen in the PC-plot (Fig.9). The plot is a projeetion whieh
shows cirily 55% of the total varianee amorig the sampies. The.eod overlapping in
the plot were found to be different by eonstfucting new PC-plots based on
sampies from fewer eod. A priricipal eomponent analysis of the absolute
amounts of fatty acids also showed differenees aInongthe individual eod (Fig.10).
Ariiong .the 10 eggs from eaeh eod feIllale, the differenees'yere larger in absolute
amounts than on relative amounts. ~o eorrelation between the fatty acid
eompositiori in theeggs and size of the respeetive eod feinales were f01.md.
··Taking·the stage of spawmng into consideration, eggs from 3 ead females in the
beginning of spawrnng were tested against eggs. from 3 cod fex;nales at the end of
spaivning. No systematie differenee was deleeted, in contrast. to the results from
individually spaWning eod (Ulvund 1988, U1\r und & Grahl-Nielsen 1988). It is
concluded trom th~s prelimimiry stiidy that each eod female has egg with distinet
fatlY acid composition. Possible differences. eaused by stage of spawning, size ete, .
are eompletely maSked by the individual differenees.
Stage of spawrnng affects the size of larvae, the size decreasing slgnifiearitly at the
end of the individual arid general spawning period. As seen from the aetivity
studies, larvae from advaneed stages of spawning showed redueed aetivity
during the very importarit period of first feeding.
The viabÜity of an early fish iarvae is a very eomplex term and is 'extremely .
difficult to investigate experimeritally,. with a eertain amount of realism. The
most realistic experiments. are to bnng .the larvae thiough ä eertain period under
the. most natUral environmental and feeding eonditions. The different gröwth
and survivcil relations of the groups are then ie1ated tovarious chäracteristies of
the early larVae: dry weight, standard lerigth, RNA/DNA and chemieal and
bioehemical. par~meters. In this war Buekley d al~ (1991b), on the. basis .of
experiments with Pseudopleuronectes americanus,eonc1uded that high dry.
weight of the newly hatched larvae increased the surVival; In general dry weight
described the survival and growth ret&itioris h\ their material better thari the
other parameters. No eompensatory growth were found during similar experiments With larvae of striped bass (Morone saxatilis) (Monteleone and Houde,
l~OO.
:
The prese~t results have implieatic)ßs for the . recruitment of the .AretoNorwegian eod in the following way: The srmillest. eggs. eome from the latest
spawned batches; trus would be of imporhiriee for. the reproduetive sueeess of the
eod. EllertSen & Solemdal (1990) put forward a hypothesis eombimng the year to
year varhition iri peak spawning of Calanus and the cod egg sire reduetion
(
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8
thfotighout the spaWning season. During warm year-s peak spawning of Calimus
are ahead of the peak hatchirig of cod larvae, giving the best start feeding to the
hirgest, presumably most viable larvae. On the contrary, during cold years peak
spawning of Calanus is sigmficantly, delayed and comcides with the small sized,
probably less viable, larvae hatched at the end of the season due to eXhaustion of
the cod femaIe.
Refer~nces
,
,
"
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.'"
Bower, C.E. and Holm-Hansen, T. (1980) A sahcylate-hypochlonte method for
deterinining ammonia in seawater. Can J. Fish Aquat. Sei. 37: 794-798.
Buckley, L.J;, Smigielski, A.S., Halavik,T.A;, Caldrone, E.M, Burns, B.R;, and
Laurerice; G.C., 1991a. Winter flounder Pseudopleuronectfs americalzus
reproductive success. I. Among -location variability in size and survival of
, larvae reared in the laboratory. Mar. Eiol. Prog. Sero 74:117-124. ,
'
'Buckley, L.J., Smigielski;A.S., Halavik,T.A., Caldrone" E.M.; Bums, B.R. arid
Laurence,G.C.; 1991 b. Winter flounder, PseudopleuroneCtes ,americanus
reproductive success. II. ,Effects of spaWnirig time, ärid female size on size,
, composition and viabilityof eggs arid larvae. Mar. Ecol. Prag. ser., 74:125-135.
Ellertsen, B. and Solemdal, P., 1990. SpaWriing strategy ~md a mechanism for
adaptive larval productioil in Arcto-Norwegiari cod. ICES, CMi L:I00, 15 pp..
Finn, R.N., Fyhri; ,H.J. arid Evjen, M.S. 1991. The respiration arid nitrogen
metabolism of AtlantiC halibut eggs (Hippoglossus hippoglossus). Mar. Biol.
108: 11-19.
Fossum, P., 1986. Astaging system for larval cod (Gtidus morhua L.)
•
FiskDir.Skr.Ser.HavUnders. 18:69-76.
Fyhn, H.J. 1990. Eriergy production in marine fish larVae withemphasis on free
amino acids
a potential fueI. In: Melliriger, J. (ed.) Nutrition in wild and
domesticated animals. 'Karger, Basel. pp 176-192.
Gnaiger, E. 1983. Calctilation of eriergetic and biochemical equivalents of
respiratoryoxygen consumption. In:, Gnaiger, E. & Forstner, H. (eds)
, PolarographiC oxygen sensors. Springer-Verlag, Berlin. pp ,337-345. '
Hiemstra,W.H.,1962. A correlation table ~s an aid for identifying pelagiC fish eggs
. in plankton sampies. J.Cons.perm.int.Explor.Mer., 27:100-108.
Hislop, J.R.G., 1988. The infltience of mäternal length arid age on the size arid
weight of the eggs, änd the relative, fecundity, ofthe haddock, Melanogrammus aeglefinus, in Bdtish waters. J. Fish. Bioi;, 32:923-930.
Hjort,J;, 1914. Fluctuations in the great fisheries of northem Europe. Viewed in
the light of' biological research. Rapp. P.- v. Reun. Cons~ perm. int Explor.
',.
. Mer., 20: 1-228.
Kjesbti, O.S., 1989. The spawning activity of cod (Gtidus morhua L.). J. Fish. Biol.
, 34:195-206.
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Kjesbu; O.S.; Klungseyr, J., Kryvi, H;; Witthames, P.R and Greer Walker" M.;
1991. Fecundity, atresia and, egg size of captive Atlantic cod (Gadus morhual
relation to proXimate body composition; Can. J; FishAquat~ Sei., 48: 2333-
as
in
2343.
Kjesbu, O.S.~ J<rYVi, H;, Sundby, S. and Solemdal, P., 1992. BuoyancY variations in ,
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9
eggs of Atlantie eod (Gadus morhua L;) in relation to chorion thickiü~ss and
., egg size: theory and,observations.]. Fish. Biol.,41, 19 pp (in print.)
,
Klungsoyr, J.,Tilseth, S.,Wilhebnsen, S., Falk-Petersen, S. arid Sargent, J.R., 1989.
Fattyacid composition as indieatorof food intake in eod larvae Gadus morhUti from Lofoten, Northem Norwiy. MaT.BioL 102:193-188.
MonteleoilE~, D.M; and Houde, E.D. 1990. Infhience of materiiaI size on survival
and growth of striped bass Morone saxatilis Walbaum eggs arid lanrae. ]; Exp.
Mar. Biol. Ecol. 140:1-11.
•
Moore, S. and Stein, W.H. 1948. Photometrie ninhydrin method for use in the
chromatography of amino acids. ]. biol. Chcin. 176: 367-388. "
" .
Maist"l, M., Kjesbu, O.S., Solenidal, P. and Fyhni H.J. 1992. Free amino acid
ecintent äs a potential selectionerHeron for egg quality in AUantie eod (Gadus
-morhua). In: Walther, B.T. & Fyhn, H.J. (eds) Physiology and biochemistry öl
. .Iish larval, development. University of Bergen, Bergen. (in press).
"
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Nikolskii,G.V.,1962a. ,On some adapt~Üionstothe regulation of populatiori
"density in fish species With different types of stock strueture. In: Le Cren and
, ,'Holdgate, eds. The exploitation 0/ natural animal populations: 265-282.
Nikolskü,G.V.,1962b. Coneerning thecausesof offluemaiions iri the abimdarice:
of fishes. Voprosy Ikhtiologii, 1(4): 659-665. Translation series No.389,'
. Fisheries Research Board of Cariada.
,.
.,
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Solemdal, P., Kjesbu, O.S., Opstad, 1., Skiftesviki,A;B.,Birkelarid,R., Bratland, P.
and Fonn, M., 1991. A eompai-ison oE. eggquality and larval viabilitY benveen
. culmred eoastal eod arid wild Areto-Norwegian eod. ,leES, CM., F:41, ~3 pp.
Solemd~l1, P.; Kjesbu, O.S. and Kjorsvik, E. 1992. The effect of maternal status of,
Areto-Norwegian eod on egg quality and vitil1ity of ,eafly. larvae. I. The
eolleetion and ehciraetedstics of the eod females, a pilot study. ICES, CM;,
G:78, 8 pp. "
,
., ' , ,
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Ulvund, K.A., 1988. Chemometrk determination of fatty acids in eod eggs. Cand.
scierit. .thesis, Universiij of Bergen. "
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Ulvurid, K;A; rind Grahl-Nielsen, 0., 1988. FaUy acid" eomposition in eggs of
Athiritic eod Gatlus morhua. Can; ]. Fish. Aquat.5ci., 45:898-901.
,
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Zastrow, C.E;, Houde, E.D. arid Saunders, E.H.; 1989. Quil1ity of striped Dass
(Morone saxatilis) eggs in relation to. river souree arid fernale weight. Rapp.
P.-v. Reun. Cons. hit. Explor. Mer, 191:24-42.
Table 1. Data on the cod females selected for different stage of spawning.
Stage of
spawning
Length
cm .
Fish nr.
Weight
Dry muscle
g.
%
Age
Type
Spawning
zones
..................1 ._4..~.~.?:
!t~
__Z_~_?.Q __ _'!..?:..~.~ _ _:._..Z
~
__..Q
.__ .1
_. ~~.§.!
__..1_L~
_..1..?.I§.9_ __'!..~.:..1..§. __ _.__._..~
_ 2
__..g
6250
2
..._ 1 _-_.._-_'O4577
_ -..- __ 86
_
_._
_
_ 18.16
_
_9
__ 5
_ .1_._.
__..1.~.;!__.._.__.1jL6_"_ .__..1..~J!.~9__._ ..__'!..?:.~? __
1..9_••_•••.• ..~.;
__••_••1
1/2
4838
70
3250
17.22
9
4
..........................__._
_ ._.. __..--. --_ _
_--_ _ __ _-- __ _-- 1
1
...............!.!..E _ _ __~..~~.~_ .._ _1.1.._
1..§.~.~_9.
_'!..?:.~.L..
.!!._ ~
~_. __
_._ ~..__
.._._ ?
~..?.~.~_._ __ ~.? _._. _._ ?'.Q'?_Q._._.. ..__1..~.:..?.~._._
__?~ _..... .. _? _.... ...._._.._.9_
4855
1_
........_ 2 _91"
_............. . 6000
_............... ._--_16.6-_
_.__ 9
. 5_ _.... ..-............•.•
2 _._._
4864
78 _
4150 _
17.53
0
..__._•••.............
.._._-_..
_
_._ 6
_ 1_
__ _
.
.
.
_.
___...
_-_
_
__
·····..··..·-3·i·4·····..·_·· "-49'65--" ..·-·--ä·5· ·..·..· -······4·5·Ö·Ö·..· · ·..·--1·5:·5·2····..·· .-..........................
.........................._ _.__._-_
__ ._.......... _
.._-_
_._.. _... .
.
......
_._ _-_ _
_ _. _._- -..
_
_._._ __..__
................••••._.... ..._ __
__ __'!..__ : __ Lg,g.__ __.1..
_ __
_
...................
_-_._...... ..
__. _ __ _- .. _---_ --..__ __
_ _
_
__
__ __ _._---_._._-_.. .._-------_ _._._-_ _._ _
.
.
..
~-_._-_._
3
483471
__
_
4
_
4590
..
_
~
4_
4
4
........
2
4
5
89
90
48
3050:17.02
_
_..............
_ __
6 4 O.Q
8750
7500
950
__
9
_
4
_
-._.............
9
2
~.l:.§.?
_ 17.14
_ 17.59
_
.
2
0
_._
_ _
-
_.
.
•
..
.
.
16.6
The scale of stage of spawning is as folIows:
123·
4-
early in spawning (0-25 % of all eggs spawned)
midway (25-50 %)
approaching the end (50-75 %)
end of spawning (75-100 %)
The code for the cod types are as folIows:
1.
2.
3.
4.
5.
Coastal cod
Uncertain coastal cod
Svalbard cod
Uncertain Arcto • Norwegian cod
Arcto· Norwegian cod.
•
•
Table 2.
Egg group
..............
__
Number of colony-forming units per egg, and results from the phenotypical characterization of the
isolated bacteria (percentage of positive tests). NM = not measured.
CFU on TCBS CFU on MBA
(CFU· egg-:.!) (CFU· egg:1.)
__
i.l!.~.:1
4855
·_·-4·5-95..·..·_.. ·..
---_
._ 4965_
_ _ __
_._~.:?..: !Q..~
1.4·10'
_
_
_
_
0
_-
?.::1..~ !.Q.!..... . _
5
. ··....· 2'1.8.10
:4··:..1·Ö·ir·
__ _
-1~3·:1·Ör·
Gram
(% pos.)
1.5 • 10 ~
__ :1.~.~..:1 _ __._.~__ _.__~ _._
...._ :1.!?.~.Q _ ?.:.Q•.:._1Q~
!.:§..~ !.Q.~
Oxidase
(% pos.)
__
Q................. .
!?
TCBS
(% pos.)
Catalase
(% pos.)
_-
_..... ._
_
1.Q.Q _.. .. _
Rod
(% pos.)
_._- ._
!?.~ _..........
67
..
:LQ.Q.
.
_..
·.·.__
. . . ·00
67
·_ · ·.._· 9·4··..·.._
· · ·..196
·0·0..·..· ·· · ·84 ·..·....·_·· ·..1100
. 0·Ö..·.._·..·
_.._ 0
_-- ._
_ _
Q
_._..§.._.._
100
l.Q.Q
_ _1Q.Q _
100
_
_
J..Q.Q_ _
_ !.Q.Q _
__ __. -_._ 9 7
_ 44 .
~.:t
!?.~
1..Q.,Q
_._
~..~
.
- .
.
.
•
5
'.
,
,
Table 3~ Composition, given as pereent of sum + SD, and total amount, given as flg/egg,
of fatty acids in total lipid in ten eggs from eaeh of eight eod from Lofoten as weIl as the
average values from 15 eod.
"
mD NO
Fatty acids
4577
14:0
15:0
16:0
16:109
16:1n7
16:1n5
17:0
18:0
18:1n9
18:1n7
18:1n5
18:2n6
18:3n3
18:4n3
20:4n6
20:4n3
20:5n3
22:5n3
22:6n3
24:1n9
Oo4±O.1
0.3±O.1
2A±Oo4
8.3±O.7
3.2±0.3
Oo4±O.O
1.0±0.2
0.5±O.2
0.9±O.2
1.8±O.0
Oo4±O.O
18.2±1.7
1.3±O.3
30.1±1.0
1.1±O.2
~g/egg
11.3
3.0±004
0.6±O.1
21.5±1.7
1.4±O.1
3~l±O.3
4834
4842
3.2±0.3 . 4.1±O.3
3.5±O.5
3.3±O.6
0.7±O.1
0.6±O.1
0.7±O.0
0.7±O.1
22.0±0.9 27.0±1.8 23.8±1.6 24.1±O.8
1.5±O.1 ' 1.2±O.1
1.3±O.1
1.3±O.1
2.9±O.1
3.l±0.1
1.9±O.1
304±Oo4
Oo4±O.O
0.5±0.1
Oo4±O.O
Oo4±O.O
0.3±O.0
0.5±O.1
Oo4±O.O
0.4±0.1
2.8±O.7
3A±O.9
4.9±O.5
5.1±O.6
8.3±O.5 ' 8.0±0.3
8.8±O.7
8A±OA
4.0±0.7 _ 3.0±0.2
4.0±004
2.0±0.2
Oo4±O.O
Oo4±O.O
Oo4±O.O
0.3±O.0
1.1±O.1
1.3±Oo4
0.9±O.0
0.9±O.0
0.5±O.1
0.6±O.2
0.7±O.1
0.6±0.2
0.6±O.1
0.9±O.1
0.5±O.0
0.7±0.1
1.6±O.1
3.0±0.1
1.1±O.0
1.8±0.2
Oo4±O.1
0.3±O.1
0.5±O.1
0.3±O.0
14.7±O.7 14.9±1.2 15.7±O.9 15.6±0.7
1.2±0.2
1.0±0.2
1.0±0.1
1.2±O.1
30.5±1.4 2704±2.0 26.5±1.3 29.7±O.7
1.4±O.2
1.3±0.3
l.0±0.2
0.8±O.1
4590
10.6
4595
9.2
10.0
8.6
4855
4871
AVERAGE
4973
4.2±0.6
0.6±O.1
21.5±1.5
1.3±O.1
3.8±0.3
0.6±O.1
0.3±0.1
2.4±O.7
7.5±O.5
2.8±O.3
Oo4±O.O
1.6±O.8
0.6±O.1
1.0±0.1
1.l±0.0
0.4±0.1
18.8±1.5
1.3±O.3
28.9±lo4
l.l±O.3
204±O.3
0.5±O.0
22.1±1.3
1.4±O.1
2.1±O.2
0.3±O.0
O.4±O.1
4.2±1.0
10.5±Oo4
4.1±Oo4
0.2±O.0
0.6±O.0
0.5±O.1
l.l±O.1
4.9±O.2
0.6±O.1
15.5±1.2
1.3±O.2
26.7±lo4
0.8±O.2
2.6±Oo4
0.6±0.1
23.8±1.5
1.3±0.1
3.1±0.1
0.3±O.0
0.4±0.1
3.5±O.7
10.3±O.6
5.0±0.7
Oo4±O.O
l.l±O.3
Oo4±O.1
Oo4±O.1
304±O.1
0.3±O.0
12.8±O.8
' 1.3±0.2
27.1±1.6
l.8±0.3
12.8
12.6
10.9
3.5±O.8
0.6±O.1
22.9±2.0
1.4±O.2
3.0±0.6
0.5±O.1
OA±O.1
3.6±1.2
8.6±1.1
3.5±1.0
Oo4±O.1
1.1±Oo4
0.6±O.1
0.8±O.3
2.0±1.0
OA±O.1
15.9±2.0
1.2±O.2
28.9±1.9
1.1±O.3
,
•
1004
•
,
1.5 . . , . . - - - - - - - - - - - - - - - - - - - - - - ,
y = 1.4674 - 4.2231 e-2x
R"2 = 0.572
o
-EE
-
1.4
a:
w
w
I-
:E
et
C
C'
C'
1.3
w
1.24----..,-----r-----r-----r-----I
4
3
2
STAGE OF SPAWNING
Fig. 1. The relation between stage of spawning of the cod females
from Lofoten (scale given in table 1) and their egg diameter.
Fig.2. Relation between stage of spawning of the cod females from
Lofoten (scale given in table 1) and the dry weight of their eggs.
5.6
y = 5.4451 - 0.13939x
0
CD
CI)
R"2 = 0.416
"
0
5.4
Cl
ca
( I)
E
E
5.2
~
I-
C1
Z
5.0
w
...J
...J
<
>
Cl:
4.8
<
...J
4.6
2
4
3
STAGE OF SPAWNING
Fig. 3. The relation between the stage of spawning of the cod females
from Lofoten (scale given in table 1) and the standard length
of their larvae in developmental stage 6 (Fossum 1986).
80
-
• •
Cl
~
R"2 = 0.509
70
I-
•
•
~
C1
w
3:
>
Cl:
Y = 75.297 - 5.3961x
60
•
C
...J
<
>
tt:
<
...J
50
40
•
•
-+--...,....--r--""""-",,,-""""--r---r--..,..--r---1
2
3
4
STAGE OF SPAWNING
Fig. 4. The relation between stage of spawning of the cod females
from Lofoten (scale given in table 1) and the dry weight of
larvae in developmental stage 6 (Fossum 1986).
•
5.6
Y = 1.0801 + 2.9407x
R"2
= 0.638
0
0
CD
CD
--
0
5.4
tD
0
ftS
f I)
0
E
E
-
5.2
0
%:
I-
C'
z
0
5.0
w
~
~
ce
>
EX:
0
4.8
ce
~
4.6 +-_ _
1.2
__._---....---.....---..,....-------1
1.3
1.4
1.5
EGG DIAMETER (mm)
Fig. S. The relation between egg diameter and the standard length
of larvae in developmental stage 6 (Fossum 1986).
80
Y = 8.3725 + 0.51384x
-
-
tD
:::1.
RI\2 = 0.948
70
l%:
S2
w
==
>
EX:
60
C
~
ce
>
EX:
ce
~
50
•
40 -+-........-,...........- - " T -.......-,----.....-""T'""--..-.,....-----,....-..,....--f
140
130
120
110
100
70·
90
80
EGG DRY WEIGHT (~g)
Fig. 6. The relation between egg dry weight and dry weight of larvae
in developmental stage 6 (Fossum 1986).
.
Fig.7. Mortality, %, in the egg stress experiment plotted
against stage of spawning of the cod females from
Lofoten (scale given in table 1).
•
•
-.e
'1:l
;:;;Q
e
:1
-
y ,. 251.07 • x"(-0.108S4) R- 0.7085
T
•
i
T
260
1 = Barty
2 = Middle
3 • Towanla EDd
4 = End
250
-=
240
=-Z
230
SpaWlliag Slatua
~
220
210
•
T
r
IDay 2 Post Fertilisation. S·C I
200
2
1
3
4
Spawning Status
Fig. 8. NPS eontent of Lofoten cod eggs as a funetion
of the stage of spawning.
0.180
- y = 0.1494· x"(-o.14071) R= 0.66927
f
0.167
I Spawning Status
0.153
~
~
~
1 =Early
2 = Middle
3 = Towarda End
4=End
t
0.140
0.127
0.113
IDay
11 Post Fertilisation. S·C
I
0.100
1
2
3
4
Spawning Status
Fig.9.
Apparent NQ of Lofeten cod eggs as a funetion
of the stage of spawning.
I
ACTIVITY
400 r - - - - - - - - - - - - · - - - - - - - - - - - - - - - -
-,
300 -
-100 -
-200 -
_LI- - - L - - - L - - - - L - - - - L - - - L . - _ . . . l -_ _...l-_ _- L
-300
1
1
1
1.5
1.5
2
2
2
l -_ _-l-_ _-l--.J
3
3
STAGE OF SPAWNING
-
darkness, day 3
~ light, day 3
E.1
light, day 6
IHHHH11 day 6 - day 3
-
darkness, day 6
Fig.10. Activity of cod larvae during hour of darkness and 1 hour of light. The
activity was measured by a ultrasound system, and the activity was
measured as nos. of larvae swimming through the ultrasonic plane.
4
•
4
I
i
PC222%
o
PC 133%
Fig.l1~PC-plotof the relative values of fatty acids in cod
eggs. Within each encircled area, which represents one
cod, are ten sampies of individual eggs (not shown).
PC216%
PC 1 55%
Fig. 12 • PC-plot of the absolute amounts of fatty acids
in cod eggs. Within each encircled area, which represents one cod, are ten sampies of individual eggs
(not shown).