,-

INTERNATIONAL COUNCIL FORTHE EXPLORATION OF-THE SEA

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C.M.1990/H:27Pelagic Fish Committee

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ASPECTS OF THE REPRODUCTIVE BIOLOGY OF THE ANCHOVY(Engraulis encrasicholus L.1758)

DURING 1987 AND 1988 IN THE BAY OF BISCAY

by

P.LUCIO 1 & A.URIARTE 2

AZTi-SIO, INSTITUTODE CIENCIA Y,TECNOLOGIA PARA LA OCEANOGRAFIA, PESCA Y ALIMENTAClON1 Txatxarramendi Irla, 48395 Sukarrieta-Pedernales, Bizkaia.

, ·2 Av/Satrustegui.8, 2000a-Donosti a--San- SebastianBASQUE COUNTRY (SPAIN)

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ABSTRACT

, _ Resuits on the monthly gonosomatic index and matürity stagesevolution, sex ratio and mean ageand mean lengtti at first maturityofthe Bay cf Biscay (Divisions VIIIb-c) anchovy in 1987 and 1988are presented. '

spawning season extended from late March t6 August, but peakspawning took place in May';'June, in both sea areas arid years.Anchovywas mature (100%) at age of one year old. Males with alength cif 11.0 cm and females with11.5 cm already appeared mature.The maturatiori,in youngest fish appeared,slight1y 1ater, than inoldest ones:·.. Differences·in sex ratio, 'at, the spawning season, wereconsistEmt in the extreme 1engths" being males predominant atlowest lengths arid females at longest ones.

RtSUME' .

Dans ce travai1' on - .preserif"e'" des "d6nnees de l' evolutionmensuelle de l'index gonadosomatiqrie et des stages de maturation,de la "sex ,ratio" et de l'age et de 1a longueur moyemne pour 1apremiere maturation sexuelle de l' anchois du Golfe de Gascogne(Divisions VIIIb~c) en 198~ et 1988.

_ La ponte a iieu depuis la fin du mars jusqu'acut, mais lemaximum est en mai et june dans les deux aires et annees etudies.Quand l'anchois arrive a sa premiere,annee est deja mur~ Males avec11 cm ou fernellesavec ,11~5 cm etaierit deja mures: La maturationpour les anchois plus jeunes devienne un peu plus en retard quepour le reste. On a trouve des differences consistantes dans la"sex-ratio" en function deO la longueur: les malespredominaiEmtdans les petits longueurs tandis que les fernelIes, dans les grandslongueurs.

1

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INTRODUCTION

The Bay of Biscäy anchovy (Engraulis encrasicholus L 1758) isa valuable resource shared by Spain and France in Divisions Vlllband Vlllc. lt is mainly fished in spring, when the spawning seasonof this fish takes place. A secondary fishirig period correspondsto the autumn.

Since the sixties, catches have been falling down, from 70.000t. to the current values of 5;000 t. (in 1989). More than 80 % oflandings are sold for canning. Becauseof~thedeclineof the stockan increasing effort in the, study of this species is being made byscientists of both countries. since 1988 an lCES WG tries to assessthe status of this stock (lCES eM 1990/Assess:24).

Routinary biological studies on anchoVy from l.C.E.S.divisions..Vlllb-c· (Bay of Biscay) -have ·been·done by AZTl-SlO during1987 and 1988. These studies refer to certain features related togrowth and reproduction. Some results for,1987 and 1988 in relationto reproduction are presented in this paper.

A review of past works made on thisstock can be found inAnon. (1988). More recently several .studies concerning thaestimation of the abundance of the stock by means,of the Daily Egg ..Fecundity Method (Batch Fecundity method) have provided net!information on the repr6ductive. biology of .the Bay of Biscayanchovy: batch fecundity (Sanz & Uriarte, 1989); sex ratio andspawning frecuency (Sanz et ale 1989, Santiago & Sanz, 1989a)~ .

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MATERIALS AND METHODS

. ,The individuals analysed were .coilected from tlie commerciallandings of purse seiners in .the, Basgue ,Country fisliing porto ~AnchoVy is .usually presented at the fish.market in boxes of about22 Kg and split in size categories, according to the riumber of fishper kg. -~ .

For 1987 and 1988 two iridependent sampling schemes wereapplied to the. catches of purse ,seiners: a fortnightly randomsampling of catches, .without... any~ .area . stratification, and CJfortn~ghtly estratified sampling., "of .catches regarding areas _corresponding.roughlY tostandard ICES divisions. Each combinationof time period (fortnight) a.nd sampling area was, regarded as asampling cello The aim of this second samplingwas the analysis of5 individuals . per sex and lerigth interval of 0.5 cm from eachsampling cello

From each individual the followlng data were always recorded:

- Total length (in mm)- Total weight (in g) .- Sex (male, female,indetermiriate)

Weight of the gonads (O.l.g)- Maturity stage (macroscopically)

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,.Also from each individual both sagittalotoliths werecollected for age determination; .Finally, gutted weight and indexof stornach fullness were recorded in the stratified samplirig~

, 'rhe .t~o. independent. ~amplings app~i.ed.. di~ferent s~~ge keys:f'C?r d:t:rInJ.nJ.ng macr~scC?pJ.c~llY the mat.~rJ.ty; But for the scope. ofsJ.mplJ.cJ.ty and for the combJ.ned analysJ.s of the data, the,resultshave been referred to a shorter maturity stage key, correspondingto:

±- Juvenile 11- Early beginning of maturation ,III~ Active (maturing, prespawning, spawnirig arid partly spent)IV- Full spent V~ Resting

This shorter maturity stages Key (SMSK) is compared to other basicMSKs iri Table 1 •

.. .,. .. .. _. .. .. __ _..... . ..

L t * 1~0147238

Wt * 1.0345679

where, ,, .. ~Le}

freezJ.ng,",' .: (Lt )

thawJ.ng;..

e

ancL. (We ) • are _the "esti.matecl" .leng'th arid ," weight .'befor,e. _....

and (Wt ) are the" observed iength and weight after.,

. ". . ',. .~ ....... ,. ..... . .., .

Conversion of. observed 'values t6 estimated vaiues is 'dorie ...automatically ·bY program; .

For ,the purposesof processing, eacli colnbination of". fortnightand subdivision of the ICES areas was considered as the samplingcell from both sampling schemes together.

, Programs have beeri written in VAX BASIC V2. 4 for ci' MiciovaxII,in order,to store,data arid to analyze results on the basis ofdifferent time periods; saxs, areas and ranges of length, weight,age, and maturity stages.

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RESULTS

• The spring spawning time is _ once more confirmed~Theactivity stages (in maturation, prespawningi spawning änd partlyspent fish) appeared with high frequencies, in males arid females,betweeri March arid August. The maxima were found in May and Jurie(near to 100%); also very high values were found in April and July.

• The basic annual evolution pattern of the maturity stagesis similar for males and females: in late winter, early beginningof maturation; in spring and first half of summer, the maximum ofreproductive activitYiin early autumn,postspawning and resting~

No sampIes were obtained from winter and late autumn in 1988.

4

• State, ,"I" (virgin 0 juvenile) was not, found nor iTl 1987neither in 1988 for one and more (l+) years o~d anchovies.

•

Length arid age at first maturity

, Fr6~ th~ r~cords on ~at~riti stages it can als6 be studiedthe onset cif reproduction dependirig on size. This has been donewith,the length-maturity and age-~aturity keys of i~87-88 (Table4 ~nd 5), which have been built upwith data from the peak' spawningperiod, i.e. Mayand June. In both tables, anch6vies are simplyclassified as mature or immature by means of a rather conserVativeapproacJ;l: "I" (virgin or juve~il~). stage., and "II" (beginning ofmaturat1on) stage refer to 1mmature, f1shes, while all other("III","IV" and "V") stages correspond to mature anchovies.

" stage "li" was assigned:to"anchovies'with small ovaries, equalor less than half of the body cavity, females with pink,ovaries andnot visible 6ocytes, males with very flattened, small and greytestes. On the other hand, stage "IlI" refers t6 anchovies withbigger gonads, females with .visible 60cytes (sometimes withhydrated oocytes) and males with weIl develop~d white testes.

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The length range included in Tables 4 and.5 accounts for allsize categories landed. It is clear, that at peak spawning time allanchovies, whatever length or age they have, are mature~ Moreover,no differerices regarding year (1987 er 1988),. area er sex aredetected., All anchovies,caught by purse seiners in May and June atthe Bay of Biscay (leES Divisions Vlllb and c) are mature regardingto macroscopical maturity stages~ Everi the smallestand youngestimchovies cauglit in May and June (1 year old arichcvies with alength around 12 cm) are mature. Unless it is supposed that purseseiners strongly bias. st6ck lEmgth cornposition in relation toinaturity -which seems not crediblewhen other months are taken inteacoount-, it can be concluded that the Bay 'of Biscay anchovy ismature as soon as it is one year old.

. ,3. Gonosornatic index evolution" .

TWo different gonosomatic indices (GSI) have been calc~iated:'-"".e· GSl

t~. Wgon';W

t.*' ~104 "~~ci'-~" GSI~ "= Wgon /Wg * 104

where,wgon is. the gonad w,Edgh~ (in~) , . ,Wt is the total body we1ght (1n g), andWg is thc gutted body weight (in g).

. . Figure 4' shows the, m0t:thly evolution ef the .two indices ofGSI by sex, for all anchoviessampled in 1987 and1988 and pooledtogether. Th~. shapeof thelinescorresponding to both GSIs areobviously parallel but gutted GSIs inhance the, gonad develepmentin spring as it could to be expected. Neverthless, for,the rest ofthe present. exposition only total GSI (GSl t ) ,will be,. taken .asreference, because a larger nurnber cf individuals can be includediri the analysis.

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Table 6 gives the numbers of individuals from which the datashown in Figures 4 to 8 have been obtained~

'. Figure 5 shows for 1987 arid 1988 years con~idered tovatherthat the onset of spawnincj' activity arrives at the same tj l[\'~ toanchovies iri Divisions VIIIb and' VIIIc~ In July a c(n~t:aiIl

desagreement between both areas, can be observed, but iri th:in caseit migth be due to the poor sampling iri Division VIIlb ~all datacoming from only one s~mple in 1987 (see Table 1 and 6).

It can be stated that the spawning activity of the Bay cfBiscay anchovy takes pÜice sinchronously, in Divisions Vlllb 'änd •Vlllc and it lasts from April to July~ =

, ,.-Length and age at first rnaturity

New information on this sUbjet can be deduced from the t:~:Idata. The maturity stage keys have always a certain degree ufsUbjectivity while the GSI i5 a rather quantitative (objel.~ti' 0)index reflecting the gonad development, directly related h> 1 ',(.spawning activity~

Figure6 presents the montl'iiy evolution cf the GSI alonc: l~" land 1988 for twocjroups of anchovies: bigger and smaller ~,h;m ,')cm fish -whichis, more or, less;, .the average size in. lan1i.ng~

Small anchovies achieve an :;lightly less gonad developmcnt t!:::':11 b ;ones in both years cf the study. Similarly"whem coinparing on·l~'~)t.e{.,.old anchovies to two ,or more years eId fishes (Figure 7), yoU!: I

anchovies present a little bit smaller gonad development thc.\Ä1. .;la(,~',ones. Ip spite of-,those"'minor-:u~f~erences,between ~hesc~ rif.. ,•..•categor~es, all groups show a s~m~lar annual cycle w~th 'n huV'increase in the gonads in the spring which' clearly refl"l,;ts "seasonal spawning activity. This is in agreement witli 'thc hic,',frequencies (near to 100%) of'the "111" active stage found ';·1"M. "and June for all size and age anchovies by means '-cf the' mat..\.1ri1:~'stage key. . :, " :.: .:. ;: " ; ''.. . ': :~" ~-:: ' " " .

Figure 8'provides ~ 'deeper vie~ i'nt'6:\he'i.On~at··of':~~t'\j·,~::;·t.if;,:>::',.,according to size. There is a relationship 'between GSI, 'len~ t:h' .(I:.:'!/: '.. :,month of the year. At the peak spawning time "Cl1ay .and Junrl) :'h)er"anchovies show. a slightly bigger GSI than. smaller. ones.. TJ'ti f'; ,';!S 'more clearly seen in females than in males,' 'In April,' when, spa m~: .J'time is starting, the differences oy length increase. Big 'anch·)V;:"smature earlier than small anchovies in April •. Thi.s. se~~rllS i,;)

indicate that a certain delay occurs and that the on6ß~ ~

6

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maturation in the Bay of Biscay anchovy is size dependent. nut onthe peak spawning time (May and June) the differerices aremiriimized: all anchovies are found at full spawning activity;

DISCUSSION

.The sex~length relationship found in 1987~1988 seems tc.be aconstant feature ,of this species and it has been already pointedout by Cardenaset al. (1981); Astudillo (1986) and.Uriarte (1987)for the years 1978-1986; .with similar _picitures to the presentresults. Parrish et al. (1986) observed the same trend for. northernanchovY. This variation iri sex ratio by size may be ,explairied bydifferent growth rates of males andfemales, but a further studyon this sUbjet should.be.necessary. tri confirm it;

The annual cycleof spawning activity locates the _peak ofspawning in Mayand, June,while,·the··whole spawning season lasts from(March) April to July (August). This has been shown by the picturesof the maturity stages freqUencies (Figure 3) and by the peak inthe IGS values (Figures 4, 6 and 7). Previous works on maturitystages poirited out the same evolution pattern in time (Cort et al;1976, Cort et al. 1977, and Sanz & Uriarte, ,1989). This is also inagreementwith results on abundance and distribution of anchovyeggs in the Southern of the Bay of Biscay during May and June cfthesam~years (Santiago & Eltink, 1988i santiagb &San~, 1989b)as weIl as with datei on yearly:variation of the aburidance of eggsand larvae of this species in 1986,1987 arid 1988 in samplingareascloseto Cantabric coasts, recorded duririg a continuous monitoringof,the plankton in the zone (Sola et ill;, 1990, Valencia et al.,1989).

Calculation of length and age at first maturity seems to bean irrelevant job for the Bay of Biscay anchovy since all anchoviesare, mature, in. the peak spawning season as i t is shown by thematurity. stages and the GSI -evolution. Histological estudiesperformed.during peak spawning time in 1987 and 1988 in order toestimate the. daily fecundity of this. stock (sarii et al., 1989,Santiaqo & San?, 1989a) found 'also that 'more' thari 99% of allarichovies examined were maturewhatever their size were; AII'thiswork provides enough evidence,:as to' confirm that Bay. of Biscayanchovy is already mature when,it is one year old" yet at,smallsizes; In.fact, males.with.11.. 0_Cm.and..females with 11.5 cm alreadyappeared mature' in ',the 'years .considered.· . ' .-

Another feature derived from the GSI is that the maturationoriset, ,at becjinning of spring, results a bit later in snialleranchovies (mainly, one year old) than in bigger fish. Previousliterature had mentioned this,maturation delay of young arichovies(Cort et al~ 1977, Anon., 1988). Nevertheless at peak spawning (Mayand June) time all anchovies have already arrived,at its maximunvalues of GSI.But also in these months, slightly lower values ofGSI are found in the smallest anchovies: this could be consideredasa sign of a certain lower reproductive capacity _ in them.However, santiago & Sanz· (1989b) fourid,by nieans of histologicalstudies that egg production per gram of female and day in 1988 was'as bicj iri one year old as in two and more years old anchovies.---

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., , ~

CARDENAS,. E., J .L~ CORT, J;A. PERERIRO & o. CENDRERO,. 1981:L'ancliois, Engraulis encrasicholus (~~) j de la mer Cantabriqueet du Golfe de Gascogne. Nouvelles donnees biologiques~ICES

CM 1981/H:2.. . . ~

CORT, J.L., o. CENDRERO & X. IRIBAR, 1976: La anchoa" Engrm11isencrasicholus (L.), deI Cantahrico: Bol. lnst. Esp.Ocean. 220.

CORT J. L., o. CENDERO & E. CARDENAS, 1977: Nouvelle lnform<'l'tionsur la peche espafiole a l'anchois du Golfe de Gascogne. lCESCM 1977/J:6.

f' .\ .PARRlSH, R.H., D.L., MALLICOATE and, R.A. KLINGBEIL, 1986: Age

dependent fecundi ty, ImMer cf spawnings per year, sex l.'atioand maturation stages in northern arichoVYj Engraulis 1'llordax~ •Fish. Bull., 84(3): 503-517.·:'

1.

SOLA, A., L. MOTOS, C. FRANCO C. & A. LAGO, 1990: Seasonal -1.+.

occurrence of pelagic fish, eggs and 1arvae in the CäntabrÜmsea and Galicia during 1987-1989~ lCES CM 1990/H:25~

SANTIAGO, J. & A. ELTINK, 1988: Distribution and abundanca ofanchovy eggs in the Bay of Biscay in 1987 in comparison with

. 1983 and 1986. lCES CM 1988/H:9~ .

SANTIAGO, J. & A. SANZ, 1989a: Daily fecund!tY,of the Bay ofBiscay anchovy population in 1988. ICES CM 1989/H:33~

SANTIAGO, J. / A. SANZ! 1989b:' Egg' productiöh.of the Bay_ of ..~.. 1: .. , ' :. Biscay anchoVy in 1987 and· ..l988,.. and spawning, stock sizeS'.

estimates. ICES: CM 1989/H: 25; .... ' ':l.~

SANZ, A. & A. URlARTE, 1989.: ..Reproductive. eyele and bateh 'q':. ... feeundity of the' Bay cif Biscay~:anchovy,~·(Erigraulis.' "

encräsicholus L;) in 1987~ 'CalCOFl Rep:~vol.30: 127-135 •

SANZ, A., L. MOTOS & A. URIARTE, 1989: Daily Feeundity.of the Bayof Biscay Arichovy Population in 1987~ lCES CM 1989/H:42.

URIARTE, A., 1987: .Estudio de ia pesqueria de anchoa dei Golfo deVizcaya: Afios 1985 y 1986; Informe tecnico interno deI Dpto.de Agricultura y Pesca deI Gobierno Vasco. JUlio, 1987. 42pp.

VALENCIA, V~, L~' MOTOS, J~ URRUTIA, i989: Estudio de la variaci6ntemporal de la hidrografia y el .planeton en -la. zona neritieafrente a San Sebastian: resultados de Abril 1986 ci riiciembrede 1987. Informes tecnicos de1 Dpto. de Agricu1tura y PescadeI Gobierno Vasco n Q 20.

8

TAßlE 1. Correspondanee betwen a) the basie maturity stages key (MSK) as used in 1988 for theroutine biologieal analysis of anehovy in the stratified sampling, b) the simplifiedmaturity stages key (SMSK) employed for different ealeulations in this paper, ande) ther MACER's (1974) maturity stages key (MACER's MSK).

====================================================================================================:

e) Basie MSK used (1988) b) SMSK e) MACER's (1974) MSK (*)

====================================================================================================:1. Juvenile (Virgin) I Virgin 1. Virgin

: .. _------------------_._----------_ .. --------:--------------_.~----_.:.._-----_._--_._-_._-_ .._----:2. Very early beginning of maturation 11 Beginning of

maturation1·3 Developing virgin2. Resting

:--_ _--- _- _- -:--- ---------_ : - _--------_ -:3. In maturation

3'. Again in ~turation :4. Prespawning 4'. Repeated prespawning:

5. Spawning6'. Partly spent

111 Aetive3. Developing (early)4. Developing (later)5. Ripe6. Running7. Partly spent

:------ _--- ..-- _----- _-:------ : .....••....••..............•. :6. Full spent IV Full spent 8. Spent

:••.•.•.........•..•..........••..•.••.... -... : .......••••............ : .......••......•....... -..... :7. Resting V Rest ing 9. Reeovering

====================================================================================================:

(*) MACER, C.T., 1974.' The reproductive biology of the horse maekerel "Traehurus traehurus" (l.)in the North Sea and English Channel. J.Fish Biol.6, 415-438.

TABlE 2. Biologieal sampling level of the Bay of Biseay anchovy obtained fromthe eommereial landings in the Basque Country along 1987 end 1988:tuTber of samples by month.

:===================================================:198 7

:.......... : ................................................... : ...... :: Division : MAR APR MAY JUN JUl AUG SEP OCT NOV DEC TOTAL:: .......... : .... .... .... .... : ......

VIllb 3 23 13 4 1 2 ,·3-- . : 49·:VIIlc: 3 10 19 11 3 2 1 5 6 61 :

: ........... : .... .... .... .... : ......TOTAL 6 33 32 15 4 4 4 5 6 1 : 110 :

:==========:===================================================:======:

:===================================================:1 988

: : ...............•................................... : :: Division : MAR APR MAl JUN JUl AUG SEP OCT NOV DEC TOTAL:: ............. : .... ........ ..... :

Villb 6 4 8 1 8 27 :VIIle 2 12 17 8 2 4 3 3 52 :

........... - .... .... .... ..... -. . .TOTAL 2 18 21 16 2 5 11 3 79 :

:==========:===================================================:======:

TABLE 3. Sex-length relationship of Bay of Biscay Anchovy in springand surrner of 1987 and 1988.

:=================================================:S P R I N G

: ... -_ .. :---_.................... :........................ :...... -:: Length: 1 9 8 7 1 9 8 8 Length:: class :- ....................... :-........ -_ .... _-_ ...... : class :

~m) : HAL. FEH. TOTAL X MAL. : MAL. FEH. TOTAL X HAL. (ern) :.......... ..... .. .. ...... _.... . ..... : . ... ...- ......... ........ .

10.0 2 1 3 66,7 : 10.010.5 4 2 6 66,7 : 10.511.0 15 14 29 51,7 : 2 2 100,0 11.011.5 5 11 16 31,3 : 40 4 44 90,9 11.512.0 23 11 34 67,6 : 48 14 62 n,4 12.012.5 59 26 85 69,4 : 66 31 97 68,0 12.513.0 123 53 176 . 69,9 : . 120 65 185·· 64,9 13.013.5 146 93 239 61,1 : 161 87 248 64,9 13.514.0 138 98 236 58,5 : 418 133 551 75,9 14.014.5 171 89 260 65,8 : 637 237 874 72,9 14.515.0 252" 112-'364'" 69,2 : 744 . 482 .. 1226 . 60,7 15.015.5 360 184 544 66,2 : 598 607 1205 49,6 15.516.0 420 325 745 56,4 : 408 615 1023 39,9 16.016.5 396 451 847 46,8 : 299 504 803 37,2 16.517.0 304 446 750 40,5 : 202 398 600 33,7 17.017.5 184 371 555 33,2 : 120 323 443 27,1 17.518.0 76 228 304 25,0 40 206 246 16,3 18.018.5 14 118 132 10,6 18 111 129 14,0 18.519.0 2 51 53 3,8 2 36 38 5,3 19.0 •19.5 12 12 0,0 1 3 4 25,0 19.520.0 1 1 0,0 1 1 0,0 20.020.5 1 100,0 : 20.5.... __ . ___ ewe : ----_.-

2695 2697 5392 50,0 : 3924 3857 n81 50,4:======================================~==================:=======:

:=================================================:S U MME R

:....... :...._-- ................. :........................ :._--.--:length: 1 9 8 7 : 1 9 8 8 : length:

: class : ...._---_ ........_- ..... :........................ : class :(ern) : HAl. FEH. TOTAL X MAL. : MAL. FEH. TOTAL X HAL. (rm) :

: ....... : .... .. .. ..... .... .... ..... ...... .......10.0 10 13 23 43,5 10.010.5 11 4 15 73,3 10.511.0 1 1 100,0 14 4 18 n,8 11.011.5 1 1 100,0.: .. 5· 1· 6 83,3 11.512.0 26 4 30 86,7 : ·11 4 15 73,3 12.012.5 16 5 21 76,2 : . 25 3 28 89,3 12.5

~;..13.0 21 4·' 25 84,0 : 44 19 63 69,8 13.0·13.5 38 9 47 80,9 : 54 41 95 56,8 13.5 ......... :14.0 50 11 61 82,0 : 78 46 124 62,9 14.014.5 . 40 21 . 61. 65,6 :. .80 _ 63 .. 143 55,9 14.5. .15.0 42 19 61 68,9 : '65 44 109 59,6 15.015.5 33 21 54 61,1·: 51 35 86 59,3 15.516.0 .26 :24 50 52,0 : 12 35 47 25,5 16.016.5 22 20 42 52,4 : 13 30 43 30,2 16.517.0 8 17 25 32,0 : 2 19 21 9,5 17.017.5 8 21 29 27,6 : 8 16 24 33,3 17.518.0 13 13 0,0 9 8 17 52,9 18.018.5 8 8 0,0 2 1 3 66,7 18.519.0 2 2 0,0 1 1 0,0 19.019.5 1 1 0,0 19.520.0 20.020.5 20.5...... : .... .... ..... ...... .... .... ..... ...... ...... :

332 200 532 62,4 494 387 881 56,1:=========================================================:=======:

TABLE 4 . Length-maturity key of male and female Anchovy fram Divisions Vlll-band VIII-c1 of the Bay of Biscey, in the peak spawning season (May-June),both 1987 and 1988 yeer samptes cOllbined.

======================================::======================================:MA L E S .. F E H A L E S

:-_. __ ...•...... : .••..•......•.. :: :-..._---_ ...... : .•.•...•. -_ .... :Length: VIII ·b VIII -c1 ::Length: VII I-b VII I 'c1 :ctass :·······-·······:··············-::cless : ... __ ... __ ..... : ..•••........•• :

(!rll) : IlTIn Ma~ ~at : :nn, Kat :xMat .. (CIl".) : IITII\ !":at :xMat : IITII\ Ma', XHat••..•..... - .... ... _- ...- :: ...... :.._- ---- :.... .... ...... -11.0 0 1 100 0 1 100 ::11_011.5 0 5 100 0 1 100 ::11.5 0 '1 10012.0 0 7 100 0 9 100 ::12.0 0 6 100 0 1 10012.5 0 13 100 0 28 100 ::12.5 0 10 100 0 12 10013.0 0 19 100 0 45 100 ::13.0 0 11 100 0 27 10013.5 0 27 100 0 51 100 ::13.5 ... 0 18 100 0 34 10014.0 0 29 100 0 59 100 ::14.0 0 27 100 0 48 10014.5 0 26 100 0 64 100 ::14.5 0 26 100 0 56 10015.0 0 31 100 0 68 100 ::15.0 0 29 100 0 66 10015.5 0 37- 100-: O' 59" 100 ':: 15:5"':" - 0 36 100 0 69 10016.0 0 39 100 : 0 63 100 ::16.0 0 32 100 0 70 10016.5 0 39 100 0 52 100 ::16.5 0 40 100 0 n 10017.0 0 35 100 0 38 100 ::17.0 0 38 100 0 64 10017.5 0 32 100 0 37 100 ::17.5 0 41 100 0 58 10018.0 0 24 100 0 25 100 ::18.0 0 35 100 0 41 10018.5 0 7 100 0 5 100 ::18.5 0 29 100 0 25 10019.0 0 1 100 0 1 100 ::19.0 0 17 100 0 14 100

• 19.5 ::19.5 0 6 100 0 2 10020.0 : :20.0 0 1 10020.5+ 0 1 100 : :20.5+. -- ........ .... _... :-... --- ... .... ::-- .... :._- . . ... ..... . ..... -..-

0 373 0 606 .. 0 403 0 664======================================::======================================:

TABLE 5. Age-maturity key of mate end female Anchovy fram Divisions VIII·bend VIII'c1 of the Bey of Biscey, in the peak spawning season (May'June),in 1987 and 1988.

======================================::======================================:1987 : MAL E S :: 1987 : F E MAL E S..._.. : ......••....••• : _.....••.. :: : ..••••..•.•.... : :Age: VIII·b : VIII'c1 :: Age: VIII·b : VIII'c1 :

ctess : ••••••••••••••• : •••- ••••••••••• : cless :.-••••••••••••• : ••••••••••••••• :(year): IITII\ Hat :xMat : IITII\ Hat ~at-::(year):.,IITII\ Hat·~at : ,IITII\ Hat ~at...... :.... .... .... :.... .... .... ••......•.... .... .... ..... . ... ...... .

0 .. 0..1 0 47 100 0 95 100 .. 1 0 43 100 0 189 100..2 0 39 100 0 59 100 .. 2 0 30 100 0 94 1003 0 44 100 0 32 100 .. 3 0 48 100 0 31 1004 0 20 100 0 .7,,100.:: 4. . 0 29 100 0 7 1005+ 0 2 100 0 1 100 .. 5+ 0 7 100........... .... .... ..... . ..- . ... ••......•.... .... .... :.... .... ...... ...

======================================::======================================:1988 : MAL E S :: 1988 : FEH ALE S

...... : : :: :...•........... :............•.. :Age: VIII·b : VIII'c1 :: Age: VIII·b VIII'c1

ctess :.- ••••••••• - ••• : •••••••• -- ••••• : cless : ••••••••••••••• :- •••••••••••••• :(year): IITII\ Mat ~at : IITII\ Hat XHat ::(year):. IITII\ Hat :xMat : IITII\ Hat XHat :...... : : :: : . ............•.. .

...... : . :: : -_ :...••.......

o12345+. :

o 97 100o 54 100o 11 100o 2 100

.. 00 1n 100 .. 1 0 121 1000 85 100 .. 2 0 62 1000 20 100 .. 3 0 13 1000 4 100 .. 4.. 5+

: .

o 185 100o 94 100o 40 100o 2 100o 2 100

======================================::======================================:

TABLE 6. Number of individuals from which the data shown in Figures 4-8have been obtained.

:=======================:=======================:Figure 4 Figure 5

: _- :- ----_ ....•.••.••_-:JGS t IGS 9 VIII b : VIII c1 :

:.......... : ........... :-_ .... -.. __ .: ........... :-- ....... --: .._-_._---:: MOIITH MAL. FEH. : MAL. FEM. HAL. FEM. MAL. FEH. : MOIITH: ...... -_ .. : ---....- _..- -_ .. ._-- ...- -.- ..... : ........_.. :

3 (MAR) 118 140 93 122 24 18 94 122 3 (KAR)4 (APR) 505 504 266 280 209 222 296 282 4 (APR)5 (KAY) 491 510 290 323 171 175 320 335 5 (MAY)6 (JUli) 428 472 253 283 166 181 262 '291 6 (JUli)7 (JUL) 135 106 91 72 19 15 116 91 7 (JUL)8 (AUG) 65 71 53 61 8 (AUG)9 (SEP) 40 38 40 38 9 (SEP)

10 (OCT) 36 49 .. 33 43 . 10 (OCT)11 (NOV) 24 33 13 12 11 (NOV)12 (DEC) 2 1 2 1 12 (DEC)

:==========:=======================:================== =====:====~=====:

:=======================:=======================:Figure 6 Figure 7

: ........_---- ......... -: ................. __ .... :: < 160 mm : >= 160 mm : 1 year : 2+ years :

: ....... __ .: .......... -: ........... : ........... :- ..... -_... : .......... :: MONTH MAL. FEM. : MAL. FEH. MAL. FEH. MAL. FEH. : MONTH:•.....••.. : .... .... ...- .... ......_. ........ : .......... :

3 (MAR) 36 26 40 59 29 33 24 30 3 (MAR)4 (APR) 147 112 100 142 121 100 126 155 4 (APR)5 (MAY) 101 85 138 178 81 95 152 164 5 (MAY)6 (JUN) 139 99 96 107 : 145 120 84 81 6 (JUli)7 (JUL) 70 48 12 19 70 48 12 19 7 (JUL)8 (AUG) 10 2 29 38 14 14 25 26 8 (AUG)9 (SEP) 9 (SEP)

10 (OCr> 3 28 30 2 3 26 29 10 (OCT)11 (NOV) 29 28 23 32 6 14 17 18 11 (NOV)12 (DEC) 26 29 2 1 2. 1 12 (DEC)

:•......•.. : .... ...- ........ ...- .... :.......... :13 (JAN) 13 (JAN)14 (FEB) 14 (FEB)15 (KAR) 57 60 8 27 : 53 63 12 24 15 (HAR)16 (APR) 150 101 114 162 126 110 132 139 16 (APR)17 (MAn 164 110 95 141 140 128 118 123 17 (KAY)18 (JUN) 159 152 40 119 152 180 47 91 18 (JUli)19 (JUL) 54 39 1 50 38 4 2 19 (JUL)20 (AUG) 37 25 10 22 31 4 20 (AUG)21 (SEP) 43 33 9 11 30 32 : .. 10 .6 : 21 (SEP).:22 (OCT) 41 45 4 13 5 9 : 3 8 : 22.(OCT) :23 (NCV) 21 23 1 1 : . : 23 (NOV) :24 (DEC) : 24 (DEC) :.

:==========:=======================:=======================:==========:

:~~===~======~==~~7==~=~~~~~=~=7====:Figure 8

: ..•.•.......•.•••••.... :........... :April Hay June

: .......... : ........... : ........•.-:--......... :: LENGTH : MAL. FEH. HAL. FEH. HAL. FEH.:._ ...._... : .... -- ... . ... ....

110 8 6 2115 5 5 1 5 1 :120 8 6 5 11 7 :125 10 6 17 5 24 17 :130 19 5 27 14 37 24135 35 16 39 19 41 33140 53 27 48 33 43 42145 58 39 49 42 46 40150 61 57 57 50 50 47155 61 59 61 62 42 43160 59 69 61 59 47 43165 62 61 60 62 32 56170 53 59 52 57 23 45175 42 57 51 60 18 40180 25 49 38 56 11 20185 9 41 8 40 4 14190 20 1 25 1 6195 5 6 2200 1205

========== ======================= ===========

. .:::'1: ...-.-'.=.

._-~

•

..--------------------------1

450

470

o "44

00

E9E6E7

30

E6ES

SO

E4E3

..... : :: .

. ~ '1' '1' .

E2

...........: .

EI

..o"'n 0""B rb

• "9 ..IMr • Sr

o "p 6 Oe

8M~ 6 Nv

.Jn " Oe

...... : ': : I-.....l...

~ . ~ , ...........................

EO

'A :~;>oo.....................L-_~~-i

15

16

19

20

21

27

22

23

25

24

47 °

E9EBE7E6ESE4E3

...........................· .

............................L--..-.----~---f

E2EI

oJn 0""B rb ~ "9IMr • Sp

o "p 6 Oe

8M~ 6 Nv."'" • Oe

EO

A :'1.........;.;>00................... I-_~~..

· ....... ~ ~ ': _-.· .· .· .· .· .· .16 ~_,;,.-._~_·_.. ·_.. ""'·~..!""".. ·~·.._....;,T_.._·.._.._·.._j.._.._.. ·_...,.. ~~..~...~..._......~,

17 C3

19

21

10°

16

15

24

.. ···ce····;·· i. ! ! >~. : ~/"/n" : ~: ~//"'''-~ /hO '''~ ~: ~: /' "/ ~/ """/'''''N~,.........:.. ~ //~

100 : ''/.,,725 : ;:::'SrutI- ....l..._ ..... -:"_.-y/....

: """'" y".1'/, lor1f'nt. ",A: """''''''''''/" ..

• •• a 0 •••••• ~. - • "1';//1//"

~. t~"hN,nt,s...... : : ~ ' ; ; /

:: ~ . : "}.22

26

23

20

27

FIGURE la Orlgln of lhe merkel sempIes, by monlh, of llnchovy In lhe Bey ofBISCllY In 1967. Ltnes (-) represenl lhe borders of lhe ICES

DIvIsIons VIIIIl.b,c.cl.; ltnes (---) , lhe Pllrltculer borclers for subcllvlslonof Vllic es usecl for lhls slucly.

FI GURE lb. Origin of lhe morkel somples, by month, of llnchovy In lhe Boy ofBlscoy In 1966. Llnes (-) represenl the borclers of the ICES

DivisIons VIIIIl.b.c.cl; 11nes (--). lhe porltculer l10rders for subcllvlsloncr V'"c es useCl for lhls sludy.

,------------ -------------

100SPRING

75 -

.~r.nL6J-J SO<

~c SPRI NG- 87

1: • SPRI NG- 88M

25

~~ •0

11 12 13 14 15 16 17 18 19 20

lENGTH (ern)

100,-------------------,SUMMER

75

25

(/')

L6J ~...l so +---------+~_=T_-___f=--~-~ ,'$t.< c SUMMER- 87 .~

1: • SUMMER- 88M

0-+-....--r-.---,r--r-r--.---r-~_r_.......--~..___..,r__r~--.-__1

11 12 13 14 15 16 17 18 19 20

lENGTH (ern)

FIGURE 2. Sex ratio values (percentages of males) in relation to thelength for the Bay of Biscay anchovy, in spring and summer of1987 ,md 1988.

100 100f\ MARCH

:": JULY

75 .'. 75 :=;

X SO .:; • M(Cl7) ~ SO (D He7) :;1' • H(8S)

0 f(66)15 2S

0:::

0::: -11 111 IV V 11 111 IV V

tOO APRIL100

::: ~ AUGUST.:.

'::i

75 :.:. .. 7S:"::::: ..:;;

X 50:;;; • M(ln) " 50 ".,.

'~H '-? • tnS!)

;~E0 F(IM) :~~: 0 F(112)

25 :25 ':=: ;:: :~;

'::; :

0:~:~ 0 d ~L --11 111 IV V 11 111 IV V•

100 100 7Ilj

MAY SEPTEMBER:::.

75 75 .~ ~ ~

:::

':~'~ ~:

" 50 ::: • M(3ge) X 50 • M(f>3).:.t:; 0 F(S27) CI F(st.).:: .:~

25 ~ ~ ~ 2S ~~~

~~i:n~

0 0 211 111 IV V 11 111 IV V

100 100OCT06ER l1II

JUNE

7S 7S:: ~

.~;;:::

lii" 50 m

- .',. .. ' . ."

X so• M('!et) • 11(9)

~~j[J reelS) CI f(la)

25~;~

25

0m 0 ~:

11 tII IV V 11 III IV V

FIGURE 3. Evolution of maturity stages in the Bay of Biscay anchovy,along 1988, 2111 areas and lengths together considered. 0 age

group is excluded. Number of males (M) and females (F) analysed is.presented in brackets. (I: Virgin; I J: Early beginning of maturation; 111: .Active (In maturation, prespawning, spawning emd partly spent); IV: Fullspent; V: Rest ing).

r-

1000 I MALES (1+ years· old)

500

600

t1) .. M(t)t.D -0- M(g)400

200

0MR AP MY JN JL AG ST oe NV oe

MONTH ( 1987+88)

';.

1000 -r-__ FEMALES (J + years old)_--,

.. F (t)-0- F (g)

-~..-....-!

.ff,.

MONTH (1987+88)

FIGURE 4. t10nthly evolution of gutted (g) and total (t) gonosornaUc index(GSI) in the Bay of Biscay ancrlovy, in 1987 and 1988 together

considered. Values are presented for 1+ years old males and fernales.

1000 -I MALES (1 + years'old)

500

- 600~-tf)

400t!::l

200

0MR AP MY JN JL

NONTH (1987+88)

-0- Vlllb-M.... Vlllcl-M

-0- Vlllb-F.. Vlllcl-F

JLJNMYAP

-,.---FEMALES Cl +years old)----.1000

800

- 600..-'w'

tn(.!) 400

200

0f'1R

MONTH (1987-88)

FIGURE 5. Total gonosomatic index (GSlt) mean va lues of tr,e Bay ofBiscay anchovy, 1+ years old males and fema les (F), in the

areas Villb and VIIIcI, along the spawning season. Data from 1987 and1988 are together pooled.

"

-0- F«160mm)..... F(~160mm)

o+,....,.....,........--.-"T""""T---.--.,....,.......-.--.--r-...--r......-..--.-~~-41 3 5 7 9 11 13 15 17 19 21 23

MONTH (1987-88)

200

800

1000..,.-------FEMALES-------,

(J) 400~

:; 600

--

1000 ~1ALES

500

- 600+J-- M«160mm)(J)

400 MO 160mm)~

200

0 •1 3 5 7 9 11 13 15 17 19 21 23MONTH (1987-88)

FIGURE 6. f'1onthly evolution of trJe total gonosomatie index (GSIt) meanvalues in the Bay of Biscay anchovy, in 1987 and 1988. Data are

presented for males (~1) and females (F) and for smaller and and biggerthan 16 cm length fish.

O-f---,--r-.....--,r--o-....,.......,....-.-...I,I-.........~~~...--.---r-...-T-.-~

1 3 5 7 9 11 13 15 17 19 21 23

MONTH (1987-88)

-0 F(l)--- F (2+)

1000MALES

500

- 600.-..."

tn -0- /'"1( 1)U)- 400 ... r1 (2+)

200

0 -'0

1 3 5 7 9 11 13 15 17 19 21 23MONTH (1987-88)

FIGURE 7. Monthly evolution of the total gonosomatic index (GSIt) meanvalues, in \987 and \988, for \ and 2+ years old anchovy of theBay of Biscay, males (t1) and females (F).

1000FEHALES

800

- 600.-..."

Cf) 400U)e·

200

•

1

•1000 _r_-----------------,

800

_ 600~-'"<.:l 400

200

o APRI L• MAY<> ...IUNE

MALESO-t--r--r__""--r-..--r-.....---r-..--,.--.-~--.-_r_-r--r__""--r~

100 110 120 130 140 150 160 170 180 190

lEHGTH (mm)

o APRIL

• MAY<> ...IUNE

1000

800 ~~/-L7- 600 ;-~-

Cf) 400<.:l

200

FENALES0

100 110 120 130 140 150 160 170 lBO 190

LEHGTH (mm)

FIGURE 8. Evolution of the total gonosomatic index <GSIt) mean values inthe Bay of Biscay anchovYJ by sex and length classJ in Apri IJ ~1ay

and June of 1987 and 1988 yearsJtogether considered.