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FISHERIES AND MARINE SERVICE

Translation Series No. 598

Rearing parent fish, with special reference to control of maturation and spawning

by various authors

Original title:

From: Summaries of Symposia, Annual Meeting of the Japanese Society of Scientific Fisheries, April 1964, p. 13-24, 1964.

Translated by the Translation Bureau( KS )

Multilingual Services Division Department of the Secretary of State of Canada

Department of the Environment Fisheries and Marine Service

Halifax, N.S.

1965

pages typescript

PAGES •

3 pages (original 8 typed pages

CITY - VILLE DATE

Fisheries -- _ . •

DeEPARTMENT OF THE SECRETARY OF STATE BUREAU. FOR TRANSLATIONS

FOREIGN LANGUAGES DIVISION

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. • . • , . •

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TRANSLATED FROM - TRADUCTION DE _

- Japanese

• 1 SECRÉTARIAT D'ÉTAT• BUREAU DES TRADUCTIONS

DIVISION DES LANGUES ÉTRANGÈRES

(1" n-eps

11-1/À-e-R`t/1-3,--0(- -LiVe—kçe rw-fro-PiR,,,

English

-P4A4

CANADA

SUBJECT - SUJET7-7

--- --''^ - ( SYMposium -ôn'rearing'--=-Ofpà-rent'fish;--with - 'Spëcial- ._ _ _ _ .

-- •, ----_77.7-::=2,.. • reference to the control of maturation and spawning),

_ _ . Environmental Effects on Maturation and.Spawning::-: - ,. . __ . _ . ----: -----• --•-,---'-•-- - -:-• 'Of Fish. .---,--. --------------- - -:-: --- ,----,' .• --- - --- - - -• --- --- -- .-.- __-_:----,------_-:__;,-.„,--,,,,._ ,-,,,, :---,,--1-- ------- 7:: --.717:--7 1. :-7 7 I-:r-:. - 7- :

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AUTHOR - AUTEUR•__7_ - -•- .•••• _ •.- _• _ _

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TITLE IN ENGLISH! - TITRE ANGLAIS

_ (References) _ _

NTAL. _,E.F__FE_G_____TS_,_mrrieuRÀTI(5e AND_ SPAWNING OF • •

_ . • •

- - FISH --- —

TITLE IN FOREIGN LANGUAGE - TITRE EN LANGUE ÉTRANGÉRE

• • •

•

. REFERENCE - RÉFÉRENCE. (NAME OF- BOOK- OR PUBLICATION - NOM DU LIVRE OU PUBLICATION) _

PUBLISHER - ÉDITEUR .

„

REQUEST RECEIVED FROM REQUIS PAR

Fisheries Research Board of Uanada.

OUR NUMBER 5243 NOTRE DOSSIER N°

DEPARTMENT .

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. . . . . . . YOUR NUMBER • " - VOTRE DOSSIER N° .

TRANSLATOR K.Shimizu TRADUCTEUR

31.3.65 DATE COMPLETED. REMPLIE LE '

DATE RECEIVED June 18 1964 REÇU LE

. Symposium on rea.ring..of parent fish: with special reference to

.By process of. maturation .pf. gonads we refe r -. to a.: course through'

Which sperin cells and ciVa.,are:forméd ,,withiii ,gonads and to a: general'.

course of transformation of tissues of gOnada the transformation :Which

'aCConiPailies the eàtniatiOnof-.the . former. The aUthOr

paper Chiefly with thé2cOnrae.:Of'':fOrniatiOn Of . oVà. inTeleostei-and.:main-

YeoStel ... ; Orie SaCLiiiice. -- structure which isjcomPletely,Séparate- froüi

cavity and an ,OViduct;':: : matnre ;:à.Va ,•are expelled, -.froM the genital Opening

through., the ovarian Cavity' and OVicluct: 'Another typ e . does, not form, a

CbM lete••Sac• thià is the type O.bsérved in, salMonoid fishes. One face

of the sac opens - direCtiy- into the body , Ca.'uity.. : It lackafthe. Ovarian

- cavity;''CiVa. are .freecl:14i4o -the: body daVity, ,: pass through: the.' n egg- —

carrying groove tt , andYare-,.exfiélled: ciutaide the body. In each ..CaSe OVa

are 'foinict on Many thin: -.plates WhiCh projeCt froni' thé Ovarian. Wall to .the

in.terior of the ovary... Egg cells initially appear in the germinal

epithelium on the surface of the thin. plate; :at:maturity they protrude

ogenesis: ie , Odgenesis,,. which is the fundamental -phenomenon. in

a) Propagation period: During this period a division of oogonium

takes place and oocytes aré:prodùced, this is the primary iDeriod

„ )f decision bf.the . nuniber-of dells which:are tO become eggs; the number

àva4idiiay he smaller , - han the'numbér oocytes produced at this

, period; however, it is never larger. in the case of fish, there are

important questions. - lef t-i,r7ith regard,- to._ this propagation period , i e,,

is . the,-}proPaiati6n period limited tb -.yonrig fish as is knownito 13e

thé caSe. in-'almoat all the apecles of ma:Millais' and birds on, as in the

case; of aMphibianS, .,is* -it ,obser.ii.éd yearly in a mature, body? and (2) -

clls sudh

solely due to oogonia or are theY 'produced also from other

s germinal, epithelium.: ,Thes.e questions have never 1Deen

clarified. Recently Zuckerman published detailed _general...remarks .'

e suggested that a propagation of oocytes

y division of already existent oogon.ia could generally tike place in

.:a maturelDodY -6e.:Éish as in the case of laMphibianS.--. - Since . then:Man.Y

acts which proved his conjecture have been discovered; thus, it appears

though. the aboiié,ccinclusion., , çorrec oWever , -.;

I . fish the number

of -Species,;, in Which the propagation period has been establiahed, is

aMall and the Prin.cipies concerning this:period are difficult to form-

tila:te . .-„The division 6f .00g6nia is observed in ,à short period immediately

after oviposition in certain species, or six months after oviposition

in .ànbther speciesi • àrid -.thrOnghout, the whoIe--year in others., Purthèr,

.Some:factorss'havé béen mentioned ,as. contributing -.to propagation . How- . ,

ever,: thé, qriestion still reMains in the .doMain of hypothesia;

rowth period: he propagation period is followed by the

'period.of-..groWth of oocytes .: The-groTàth period can-furth.er he divided

into thel.Priinâiy grOwth,périod and the Secoridary groWth'period..' The

primary ;grffi, ■Tth' period 'corresponds-' t

ivision and corresponds - - to.....what the a.utlior has -' defined as the karyOSOme

etiod and periplasmic period: - Éggs with diameters,: of leas than approx-

Mately 150 i belong -:_tà'''this period: One .of the • important phericimene_

taring this përiod i:s. the halVing of diplàid chromosomes and the formation

)t pla.aMoSome. The :other: is the 'formation -fof follicle cell: layers'. it

is believed -that' . the -first „phenomenon is related- not only tà :heredity

but --"elso rtà the mechanism . Which 'regulates the 'direction wherein egg.,

--cells are transformèd into èggs.. . The follicle- cell, la.yers_:.Play :..an. _

important- role in 'supply:frig. nutrition tà eggs:: and consist of three Cell

origin of ,the -constituent zcèlls . à.nct the relation bëtween.

‘intr:annClear, transforMatiOn ,:àniliegg:, r :toWth are the ftndamental PrOblems _

n ..C.ell- d fferentiata :on, and ettidies are:being, carried out at the :

reeent 'tiMe;

e : important ,PhenoinenOn in the secondary growth per iod is:th .

accumulation - of yolk , becatise of this the VoinMe of sthe • èàg. increases,

maricedly ,..Three ". .kinde of nutritive granules, ' yolk cells-,- .:yOlk.;'sPhere,

formation takea -place Stetting a.t the periphery' of ‘ - the egg towards the

t .the end of 'the aëCàndery grôwth peri64 the 'Yolk:

themselves in ràWe arôund::thé . ëgg; , in a mature . égg ' the

bnr:iëd in the surf ege:' ,.prOtçiplesm and becOMes :what, is'-kriôwn as the

-.membrarie'separatiàn ..'i-s The yolk -:sphere

fiSrins • one large •

yOlk -mass and in -Other, -Caaes - , it Ccriats of :Many' large-sized 3761.:k' .: sphéres.

In .both cases . ,„ . it appears in the Cytoplasm between- yolk cells in the

form.. Of sinall -yolk granulés at the beginning of its 'formation, increases

gradually both in number - and size, and finally comes to occupy a good

portion of the egg:.. the case of the former , . the ycilk : ;spheree • fuse

and form one mesa . . The main''.Component of thé ;Y:bik 'Sphere is lipid

rotein to which polysaccharides and inorganic substances are bonded .

il s peres are a so recognized in eggs of many fishes • however , there

are spécieS - -in...Which they are difficult to reCognize. The oil-- spheres

*appear àenerelly on the periphery of the nucleus, and in time appear

around the periphery of the egg. The time of their formation differ

somewhat depending on species, i.e ; in sOrne''spe-ciea they ,alppear before

other•„yolk; In some they appear_ arôund the periphery of the *nucleus 'soon

after the start of the . formation of yolk cells•n and in °there:they appear

at a still la:ter period It is believed .thet • the main coniPOnent is "

glYderidê. The Origin. Of '• the yOlk' is one of the Central teaks of research

n:the dévelOpment. , àg the egg and .; néw fects are repOrted. one after another.

'Againi• one of the important: changes : during this period is the formation

of the égg'mémbrahè celled- the radial tine zone (?) a thick membrane

which is cha.racteristic of fish eggs , is formed. During this period',

the eggy yolk _cell- period, and the priMar3r, secondary, and tertiary „

egg yolk periods are .defined on the besis of the degree .of formation

the egg.,',Yolk."

(c).. Mature . period During the mature period polocyte is released

as thé .result of the Primary. Mature di- ision ,. further, egg s . . are

kpelled . frorn the fbIliCle Cell-, layers': The two *things, are greatly

ifferent in cheraéter; however' they take place anèceeding . ..eech .other

and it appears as thdugh they are related::: n...many ',species of fish,'

.gra.dually :begins o iricrea se those.' of the folliCié cell peri6d appear

...H6Wever, .the:ituCieuS.mCives'.-tio Per1;q:

this omenqn: seenia to ..occ 1,1"- result of the difference 111- the

polarity- of .egg :yolk formation-. In some cases, - -OcCurs -in .. peridds

other ;than .: the maturation perio e division of the egg nucleus, the

formation of the follicle. rupture portion, -2and the release i eggs:fT9m

it are characteristi:c of this periâà:. 'Ther,e are many problems ...such as

the factors related.,to these phenomenon which. await futUre . developrderit

ni research.

-Periodicity of oogenesis and gonad weight ratio: The gonad weight

ratios of -MicroStOmue stelléri Schmidt shoW-'à 'period.icity of ,a year

Ihey are at MinimUmr. in'.June , and:July, being:leas -than 1 7 ; lioWéver,..,

they gradually' inc.rease starting.:in . Septinebér, ,. and reaéli aPproximately

: 107 in January After this , they: inéreaee 'anddenly, and , reach:: à .

maximum of 297 in MarCh; after this they ..deéreaSe ra:PidlY' again, reaching

,approxiMateiy 1% in May one compares this to the periodicitY of

ovarian:eggs, one reCOgnizes., eggs youn.ger than .-the r periplasm period . .in

.the..-ovary..throghont the:Year. At -- the . tirnel:when- thé .Weight of the Ovary -, ..

. Withiri the - Ovary'.; with the , appearance , ôf :;éggs of :the , ;primary =and:„second-

ary .perio( the Weight of the ovary -increases: Especially with the appear-

, ance of eggs of the period after the tertiary yolk period the weight

of the -ovary ingreaSes anddenly;.. and With their disappearancei,it e-.-

creases suddenly., :Thns, - .'.the variation in the 'ovarian weight, -rscontrolled

mainlY::by..:,the;presencel:.br- absence Of eggS of the period.: The

pericd-cif, a.ppearance of egga-,with"yolks of various periÉnt.à • is ào±e ;

eggs of different - yOlk..periodS:are not "fbun.d together within thé seine „ : •

ovary at the same tike.': rire gOnad •x,„Teigirt ratios in killifish do n.Ot.

.Vary much-during . the period from .:November to the end of March, when.'

average; -hdWevér they incréase suddenly , they . are : approkimately 2 7 , : on . the

•

and.,:reach. : apprOximatelY...9..5 in the middle of mày..

Then; the Value gradually déCreaseb and bécomeé. 8 7 on : the average in Julie,

in'' silly, 67 in Atigust': - -it 'remains at even in ,SeptéMhér

'-creases to 27 in ÉToVeMber An examinatiàn' of the 'ocCurenCe of 'àvarién

: . éggé Shows :. thé présence throughout . thé year ,be : egg .,,Young er': than the

-97.k , Cell period; the eggs : in the primary .yolk period appear_ at the end

of 'March, when. the oVaria.n. weight 'begins to .:ïnCreaSe: Thè.:périod when . .

_eggs .of the secondary and the tertiary yolk Period are observed 1.s the

Period when the ovary Sudderily-..becoMes larger: The 'éggs- of these pèriods ,

aré. ôbseryed . continually to .SePteMbèr; hoWever, eggs of the mature

period or of .the complételY Mature: peridd'. are diffiCult to observe::

until èarlY on the 'day. of 'Oviposition: . :Even in fishes of this spédies, , -

the incréase in ovarian weight is brought about by the appearance of the

„...yolk 'period. The difference:_ -„is: .-that eggs:of all the yolk periods : remain

n thé iivary.- for a long period of timé_and' during thé oviPositiôn: period ,

all yolk periodS can be observed in' a single ovary.

. " Salnion.;-trout -thè.' gonad weight -ratio iS ldrei,' being approXirriately

5 7 until:::about February ,.àf - thé year 'whén àviposition takes. - place,

" .17 in April, and 1.8% in May.

The Period between ._Tuly and the beginning . of September is the one in

ègg

, . which sudden weight increases are observed and immediately prior . t

„oviposition the value is approximately 27 7 . A compariSon of this with

the period of àvarian eggs shows that the inc.rease in the 'weight of

gonads is brought about bY the appearance of eggs of the primary yolk _ SuNce, -Lie time of appeârance .01,)e_9(3s orthi mmits_ jo11 t,e‘2‘0(1 PeriodiAis April. And the sudden in.crease in the ovary is due to eggs

periods later than the 3rd yolk period. In salmon trout as in the

case of sole, eggs of various yolk periods appear at distinct periods.

is not Possible' -td observe - éggS , of t

.,iplasm period t roughout. the year , • when .'eggs Of " the Yo

qas --cleàcibdct,aboVe .

tWartaii. eggs.

ebua occurrence" type ThOse belonging-. t ', type

timeS during their life' spans The perio

this type • lay, eggS several

oviposition is short and-

Ied thè, "non

ave a long oviposition period an

the "pérf edt.'

only

. . The'iMeChan.I.Sitt. thrOugh

exPlained 'stiie; present ...time.. ,

ariation in the rLumber of „eggs which 'adcompanies the time o

with the time o occurrence? The first question is the number of egg

ardly any olata, concerning' -

edttiréd' that the ninnber : is enoritiblisly large in comparisiin to the ,number

_ . author. in killi-

'iSh whOse: reproductive

,...tbel,nninber.:t of .'„'e; ëell's ,which 'are produced

uring' "à pericid of..onei year In. SuCh specieS .as rainbow' trout,

With 'reference tb 'eggs a.fter .the periplasm period there are some data

ReStilts,. :which were obta.inéd in rainbow trOut of one yea.±- .. ..shOW' the

, - iitif.nber of oVeriari ,seggS of the periptasm period_ to be approximately 4600

leth the :adVante in the7otturrlee -:periOd;- the ritinibèr gradnallY detreased

o 3800 in the follicle period 2500 in the oil sphere period and 1300

n the primary yolk period. he . , ntirnber further detreased slowI-y, , an

; was approximately 70.0 inunediately, before ovipositicin4' This tendency in

'.the variation of nuniber agrees with other ,data. Thus; it 'appears as

tholigh -the ovarian eggs which take' part in -ovipositi.on, decrease

markedly during the .primary , groWth period'. There is à fiyPothesis whi.ch

roposes that a part of reproduced egg cells change to follicle cell s .

e mechanism of thia decrease is not too wen known.• 'i"he : decrease ;

Which is '_obserVed next, cittiira at the beginning of yolk forinatiOn.

Since in the case, Of . reinbbw -.trout-dissociated' eggs are not especially „

numerous, it appears as though the decrease is due to the fact that only

part of the eggs: of inaley périplasni:-peri6d: can Change into egga ,:of

the yolk period.

ation; however,

The ,hyPophysis hormone 'takes .Part in the yolk form-

the 'reason Why the yolk:forMatidn.is stiinulated in Some _

eggs : .Whiie is: not affetted iru. -Cythers is not knoWn.. We can only 'fi

vaguely say - that ,i.t. IS due to :the .differente in sen.aitivity due to: the , . _ . -

differente in the degree of occurrente:. ' After the primary . yolk period

-,until completion « of maturity, the number': of eggs detreaSea gradually:.

The decrease - during this interval is due clearly to the -dissociation

of a r part of the eggs. The number of dissodiated eggs depends on the

. , • „ .r, _ s, -:the detreaSe in the nuMber Of egg.s' during this

period:: depends-On the quantity of nutritive subst%aces , Whith .are :Süpplied

:o the eggs' by parent 'fish.' This is alSo .supp .orted, partially by the . • - :-

act - that the 'number of eggS colleCted is PrOportiorial to the size

thé

at the . iség

the nutrition of parent fish

the biological effects of increasing the nimber of .'eggs',or..: of ;1-10.rigi.ng

the -'.. • iod on the efficiency of ,..egg formation, it becomes

- 1 te the egi" formation potential We do not ,believe

tilat

' 1-1y - e3Éâniined.,-r ' Ho;° e'v'ér,.. we wish . tci`' publish , an -

experimental 2 c1. à for thé clonSideration of those who may be interested

' - in'i.this '.:phase of rser-f-1. ,First..0È ail 'sthé'ÉgS.gorlat--12.n-...,8..'thoug ht

meta.bolic pr'Oceas;.

where

ht of

egs;- -.1è- the

-

is the oviP" • iitêrva oSition i

• . of' -earkP,

boW --trout'

seal--eel and Morone labrax (Chieffi and Lupo

Ga1zigna : 1961) Hisaw and ....Rot 96.3),

1961 ; 62), rain-

e confused results of the past will not be possible. ion for

10

ii. Biochemistry of maturation Tadashi Nomura (Tohoku Univ. Agr.

With P Y , _ _ éferenéé to h changes 'Which.: are observed in • .

'gcinada with tha . progress of maturity in fish, reIatively„. .mtich -knowie

has been gained'on .-Salmoriôid eiShes;:-hoWever, very. little 1:s known

much knowledge

i 'coricerning ,metaboiism or .physiology,.a.teach stage oogénesib or SperM

t follows, is the mOst récent bi:ochemical ,research

- "Concerning maturat ion, with: . Specia.1 reference' to research. on -the femal •

' hormone, in which the ant.hor part OnadotrOpic hormone: The

existence Of.'estrogen ..and-i„getogen has 'been* anticipated and hormones - Of

the female

reatilta of reaction. and fôr, other reasons; some investigators anticipated

specifiè singularity in fish, and others u • . .• - •

quite - recently: expresSed

the belief that sex hormones in fish were steroid (Emmens, 1959) .

owever, the existence of estradiol 'in eggs of : shark wa.s chemically

established (Wotitz et al 1958) and small quan.tities of estrIol, estrone,

and- , eatradiol ,Taére detected in the ovary of lungfish (Dean . and Jones;

their presen.ce ,was confirmed mainly in mature ovaries

and "koroshi" - (NOMure,' 'Tsuehiya,:, 1963) ' and. sex hormones of *fish were.. - - .

ideritical, with estrOgen, .progedterone,'. -or androgen:in ma.Mmats , and the

questions posed aboVe havé tentatively: been anawereds'éi. However, unless

the differences in the quantity or quality of hormone due to species,

or thé .variations during Maturation; can be established ; a :;ftiil explan-

. separating the ovarian ,. sac from the ovary of ,cod fish and by -a

cluentitagve*deterMintiOnOf'.estrogen, the. existence, of approximately

1/I0 of eggs,:of estradiol and of_ a' trace Of 'estrogen. in inimature eggs

hae beerà';'establ i;s1 .1ed (Gottfried et al, 1962) - , However, , none of the

above results makes a comparative examinati_On With referenCe to corre

ati.oe, with ,the degree of Maturity. I :'; • ,

ii. 2:the Other": hand= ref èreriCè:::t d'eStregérin.'-blOOd, , the - 'àùtbOr

and others for the first time obàerved its sea.sonal changes in eel, carp,

sea-eel., moray, and Atlantic salmon using the gonad-body-weight ratio.

.G S): as à 'standard of maturity_ (Cédard, NoMura,- ,With, respect

. to -eels, we 'did net observe : the difference whiCli we had expected between :

silVer :eel and ,yellow' eel with different'RGS; we :fa.iled to obtain

uniform results on -certain species . with ,respect to RGS and :estrogen

contents. • In Atlantic salmon hemal estrogen content was high in grOups

oing :up rivers f- dr''ôyiposition.. in December, and 'low in immature sa.lmon

r in SalMcinïf't;ffii.Ch. - .had laid eggs , of the aairrie:.'sPecles

'riVers in thel-apring ,., Estriol kaa.: s .fotirid. in salMon:ln December; it is

suàPeCted that the presence Of ‘a large qùantity of ; estriol during the

oviposition., period may .:cause , swelling

oviOpoetor open.ing' and„ may facilitate spawning and ,ejaculation of sperms

Cédard, Fontaine, and Nomura 1961).

enerally RGS is used as one of the means of expressing ..th e .

b.owev,er , it is strange that

estrogen does not inerease wi.th the increase in RGS. Will it not be

necessary to consider the behaviour of fish towards sex hormone, which

ls - dèscribed'Iy Hoar, or Pickford, or Egami; the fact that there is

hardly anY testesterone in the.testiculus of Morone labra.X, but that Corvus . eurn horrno nè, or e.e..to_àè.r. - are i'co,..tbc4 (L1/49b0 .ct . IM'eff • tg L.Ï) -Fha A the effeCts of the extraction .- Of the ovary tend' to be less distinct " -

:than, .the .effeete of the removal, of the testicuIus (Ball' and Bacon, 1954), . •

. •

f the collagen tissues of the

degree Of maturity; there are case s -. in which" *:

12

or the :faCt .:.that as à sexrially ,

unstable period during the , immature period; or the fact that sex

transformation takes place easily (Tokio Yamamoto) in conjunction with

s: and e'strogen .Content . ?

enerally sex steriod is recognized as being responsible for a

_ iva.tirig oogenesis and.:_,gona.dtrOphin for stiMulating'3'rolk formation

Yamazaki; Yamamoto, 1963) (Ball, 1960); the source of estrogen is be-

liéved to be the - closed -i-fcalicle. Estrogen:is also recognized' as having

_ - - • ;reventa.tiVe effect during...the secondary' groWth period o

..eading to the Cloaed 1954, and others).*

bodyte.an■

It is belieVed

that this is .caused. by .the suppression of production - of gonadtrophin

due to the feedba.ck of estrogen to the pituitary gland (Bali, 1960):

. . . . • .thus, - one must . be'mindful' of _these._ factS,:in the method of .adMinietering

..hormône . or in the . arialysis , ôf the Confused 'effeCts.:

Research on the biosynthesis of sex hormones in fishAbeing under-

' . :taken: at long last... .-±t wa.s ',reported that :.'When'àtrogen was injeCted in

the dorsal ' muscle o: a speCiee7of ,ACanthopterygii ; estrone,. estradiol,

and eàtrricit: of the 'bOnfid i 'tP-se..Were _ , •

he fsi.i.trotinditig water. -

....(Ittrich; -11.1<étdteetbeterone 'Wee,•aéParated - ..frOM..ithe•.blOOot

plasma: Of sockeyes which were giong upstream for oviposition.; its con-

tent rose with the rise in RGS. The content was grea.ter in than in

testosterone content is higher in .î than in and both become..lower ,

r.after siiawning; in -1-...eapecia.11Y'-: :IlketotestOstérone disapP.ears':Completely,

Liner et al, 1962) Since then:the prOCeia Of SiOsynthesis of -..this

. hormone has-been flirther . clarif.ied - (Ldler_. et . .

On the Other hand,: a',rea.d.tibn, in which' C21 steriod changed, intd

obseriTed in ovaries of dace (Àrai; Iroda , Tainaki - 1963 steriod was

n addition the presen.ce, of...3 -6 -dehy rogenase in ovaries of Morone

abrax was estabilahed (Inpà and Chieffil, 1963)- 'For., the firat time

éstosterone of the bound typé''was'..f6und :dicing with a:large - quantity, >6

stèriod

. . Other, hormones and maturation: LH and FSH_are _thought to be. - „

resent' in fish (Olivereau, 1962) (Witschi, 1955); however, whether, or

ot FSH is identical with the one in manunals is _open to question (Yamazak.i,

•RecentlY; gOnadtr6phin. With the same effeCts as LH of,:NIH4 was

prepared!frOni..thé• -p'ituitarY...ôf-Carp:; this niaterial_iS; alightlY.,diffèrent

froM LH, of .n.,anunals; and - it_WAS reported that its mO1éculAr Weight WaS

lea's:then, 30000" (Éontaine;and-:Gérard 1963) -: . - It-WaS.:eSeablished - that

'SH:Stinnilated sex glands in sharks (Ramasmani and Sundararaj 1956).

Sinée then it was found - tha .t its née, Singly or combined' with gonadtrophin,

w-aà. :found: to be .effective in eels - (OliVereau,. 1961)- -(rontaine;' , 19,61),

stickiebaCks (Ahsan and Hoar, - 1963; and gàlcifiSh, and lepbniis Sp. (Sneed

;rotease (RaWaswami - 1958): -a inere . disS6lution:bf . growth hormones in . , ,

Water,in which' fish- are reared .is 'found to be 'ineffective : (PiCkford,'

1963). ..The: content of 17-0HOS in the blo6d . of .'salmônoid fish .bécàmes

iglièr - >With'the approach of . thé:anadrdmous.-oviposition period; t

reason for their death after'oviposition is believed

•During

wéxler, re

. ›. _ • &iced 'j.-il•t49,

-

interrenal (Robertson and

eas . °

cort?-c

_

oid

É

,

o

. . maturation, •

ifferent structure '.frorn: that _in:Mammal.

ith_respect t6: neurohormones, Arginine vasbtocin, with a 'Slightly

has been séparateçl; recently.

. so to cin emporary designa.tion) (Serine 4-isolencine 8-oxytocin), was

recognized (Acher, 1963'

This Seenis td - be rela:t'écrto. àviposition or -spawning; and to the

sioaTi;Riiig reflex of the ?...(SaWyer and Pickford, 1963)„ (Egami, Ishii, 1961)

(WilhelMi:' et al, 1955)- ....,..-Recen.tly.,:' in addition. to the :above;.: utilization

of protein-assimilatory hormone (Hirose, ,Hibiya, 1963), .has been tried,

i.e. an attempt has been made at reproducing gigantism in fish by the

use of growth hormone (Enomoto, 1963) also ears' :

rang .haa been:me/le in the clarification of the::regulating mechanism • in

light

treatment of fish (private correspondence, Homma).

Relation: betWeen. --nutritiôn' and Maturation: : denerally diiring the

reproductive the speed of growth.: becomes , -slower and the en.ergy

reqUired , ;fôr groWth is_- :nsed. for the develoimient, of the gonad (Minoru

n brown' salmon-trout, the factor :Which wd.s' re,sPonsible

. or . the egg ,diaraeter and the weight wa.a feed and ;:not the' -amciunt, of sun-

shine - (Phillips et al 1958 '59) • it was reported with respect

Plecd-glcissiis altivelia (TeMMinck et Schlegel), that when Maturation

is:Controlled by . light treatment fat in the coe oma enck-ec to, decrea.se

when maturation was in.-progress- and to increaSé at . othertimes

"I'. 9 6:3 )

°or apPetite or ,faating; Which acComp+

any Matnration in many sp' eCies; is attributed to the tension in the

sympathetic nerve (Fontaine and Orivereen., 1962) -: . In darÈ..s thére are ,

è's of' the egg at the time when-'the 'yolk changes in 'various componen

begins to be ,accurnulateci , ,d.urin,g ,- the maturation; procçss „,of ovaries

(Karitani, Shirahata, 1955) . The amount of ovarian dry substance of

codfish increases with RGS but decreases markedly immediately before

)Vitâaiti6" (nraCkkariand:- ,j3-dge; A- general componée:change_inj _

ggs of rainbow trout during the maturation of eggs takes place in the

orm to accumulate fully components which are necessary during the

ii other ha.nd

-:saImon in the PaCif ic—the dif ference: , due to the:degree of maturity

:in-essential, amino aéld content;- in -fish: egg S was that while: arginine

and -trYtit6pharie retriaineci; constant, thréonine- decreased with 'maturity _

Seagram et al - 1954) . The lysine content in muscles of codfish an

sturgeciiis increases .chiring 1954,.

•,(3udanôva, • 1952) - . Further, there are Studies . WhiCh..show. , changes in

àiro_fià a:c ids :12ri relation to spermatôzôa formation, Ihistone in

Salpio . ::ts.ChawYtscbaaTalbaupl:• changes into prbtarnihe bèf ore the formation

of spermatozoa and at the end 0 E reducti°n eivisi°n (Alber

and the protamine formation and the maturation of spermatozoa -r

' Further , àrginine

- qiiantity in these proteins ls:'ribt synthesized in - • '

the 6Varybut- . is tranSpOrtedliY the côtiipi:)untis of the bàdY';::.(Terréiine 1952 - •

.iiii.OreÉes Tint>: maturation, . . _ .

Shore' ,(Kilbos,,

-increaseSat about - :the time when dogonla cleelop into oocytes an

ecreases at about the time when yolk spheres appear (Potrova 1956)

uring the ovipository eCutsibil. of ,sockeyes - ..RNA-q) .-in muscles, digestive

ehàd AeCreas es 'and ,,DNA:-.P ancL Mil 3,ncreas

here- iS Sa‘..'ClOseirelratiOn hetwéen reproduction. In,

erring with the same body length the reproductive power is stronger

in thoée : with*- 'a - - Larger -ainciunt of lipids . (Ànokhina; 1959)_:. Unsaturated

acida in lipids ..of salinon_deçreases Markedly:: imMediately- :before ovipOsit--

iOn Shoma , .Hatano, Takama, 1963). In :. Parathymn.s mebachi

(Kishinouye) and soCkeyes chOleatèrOi in the blood' increaSea' with

Maturation . (Shimizu, . Mono, i 1963). (Ldler and Bitners. ,, 1958) (Ledler

and Tsuyuki; : 1958) An injection of estradiol in goldfish stimulates

the formation in liver of vitellin which môvéé to the ovary, CuMulates

in developing_ egg's, and form" s the main Component . of «yolk.' (Ba.ileY,'_-:1957).

Fatty acids in carp--eggs show -a composition which leads one to ,

suspect that they were transformed directly ,from body fat (Igarashi,

aOka.2,:_.: 1960

HistochemicallY,'-`pôlYsaccharides and "mudolirotein were :detected in

yolk cells; lipoprotein wa.s detected in yolk spheres, and glyceride

and cholesterol in oil shperes (KiichirO Yamamoto, 1958).

There . is a relation between the variations in the a.mount of glycogen

in the liver, and gonad and those of 'cortical hormone (Chang and Ldler,

1960).,. -It ,is'sa.id Of rainbow trOut that hatChing is better if 'large

uantitiea caroten.oid and Violaxanthin. are present (Hirao, Yamada,

iktichi, 1954) There are variOus'repôrta Oil the :relation beeween

antà.thénic adid . ,- B 1 , .:311.t C and reprodiictiOn . (Brackkan. .and seBoge,' 1955,

ri .o

relation ' between - pantd -thenic acid- . and reproduction • Was obserVed (Yanas

tendencY for Vit 'A to inCrease: wi

(Yamanturà; ;1953) (Mu:to; private corresporidence) (Nogu.dhl, rOfikii,. 1953)

(Higashi; Hirab, Yaniada, Kiluicht, 1958). In ,additiOn tà, maturation,-:

it E is effective against fish diseases (Hibiya Sato

between. nutritive components and .maturation, • one nitist observe; howeve,

that the clarification of the question of how they ..reactr and i a.t w

ish -terminate their lilies .by- . a single reproduction., orne Species o

18

dOntrol bY internal .:- SecretiOn-- Of maturation - and oviposition

Fumio Yaihezaki poi, Marine)

Since. Much: of the research on Maturation: and oViposition in fish

ha.s: been 'conducted fbr, practical application; and since there have been

feW fundanientel biologica.1 and - chemical .studies, the knOwledge

taimentary . and there. are man.Y.unknoWn points-,concerning the mechanism.

hoWeVer, jithey -repeat- reproduction peribdicelly 'through. :

fiXed.proclesa of, yolk formation, ovulation, and bVipostion. Furt er,

the 'term maturation gen.erally inclUdes yolk- frbm'at 'ion. and ovulation.

However , it appears that these' tWo . phenomena do:not occùr under 'identical

'medhanianis, but that they belông .tb :totally different mechanisnis; thus,

in the present article, the author intends to observe the endocrine

mechanisM" of Maturation and oviposition in fish mainly With reference - - tà :pituitary:gland , hormone under, three headings -) lk : 1 yo formation ,

_

2), .Ovulation, and 3-). , oviposition

.GenérallY, Yolk:ffirnietion in fish ordinarily

egins in', eggs '• of a (1.1'.ameter of `apProXimat eiy 100 ,7 200;1

Yolk formation:

he period

.required dif f era among fishes but extends from several weeks to several

:Mbnths; there:: -are. COSee :where' the pericid 'extends .oVer a».year.: :There-.

'-Ore man.Y :.'pOinta'-unknOwn. at thé preeent:-tinie cloncerning the hormone -

mechanism of yolk formation; oWeVer,' t is clear that it - relâted- •

ClOsély to the pituitary gland. When the pituitary-I.gland.f.ïs' remOVed

:rom a 'maturing goldfish, - elmOst all the .,egga •With'.diameters.- over •150

cbilepae. The eggs niost 'Markedly -affected are those - in the range - 350-

750 ; eggs with complèted - .:yolk accumulation and :thiise in the Yolk-:.

cell period, ,remain in the ovary for a r.elatiVelY longer period. HOtq--

requires seVera.1_ moriths •à teriiperàture , .. •

20°C, for',1nStanCe,:.

removed, there is a clear indication that yolk mat ion is induce

19

ever, 'if they are kept oiïer a :long period-, these eggs .also collapSe and

the « ()Vary Carries- only eggs withàiit ,.yolk. aPee'ci''-of:•;collapse .differs,

at 25 C;,•-they ,bollapsè in about ' 2 weeks Thus, the extraction of the

„ Pituitary , gland' reatilts in the remarkable càllapsé of eggs, with yolk; the

OweVer ,,

Vivien, phenomenon is known in a ,speciés of goby (Gobius,paganellus,

1941) and in a species Of . :Sole-',.(Plenronactes platessa, Barr, '1963

bvn, the Other: harid. ': 1 Whari . a :Pitnitarylgiand:is either tranSPlantad

r injected into the , indi.vidual from which the pituitary gland Wa.s

It appears that the pituitary -gland .used'›may be of any species,. o f ish.

is indicates the existence in the pituitary gland of fish,

ormoné ' which. s imulates the , formation of ydlk. The hormone ; haS, not',

een extraCted chemically to date in the present article, s. ‘f or7'; the' .,

Sake of convenience, the horMone ,, Will be • taMPOrarily ref erred ito àS

, - vitellineatimulating hormone - (VSH). , In inammals ..:there is -follicle--

stiMula.ting hormone .(rsH) in the pituitary gland; J.:t actd on the-ovary;

stimulated the propagation Of , the . •grannlar :membrane. , cellà, the Séc-r- •

'ration-. of the follicular_.:fluid, and the Maturation of egg Cells. .., Thils,

here :_ one encorinters the l prbblam of ,the relation between VSH and FSH

owever' ; Many researCh. 'wdrkers . i'efiôrtéCin, in the Past that-'.the:InàMmalian

pitnitary glands and the sex-gland-stimulating- hormone-réagent._which.,

is extracted have nô efleCt..on the maturation of fish ' (Pickford : and

a lso- has no ,effect .on the mat-

uration of 'fish. , (Pickford,. 1959) ,. Furthar, ,: the administration of the

mammalian se .X.- gland Stimuliating-hormone,-Lreagent to gold'fiSh,. from which _

the pituita.ry gland had been .removed, did not indice the formation of

2

Witschi (1955) repc,Irted that the pituita.ry

gland in fish had exttemely weak FSH- effect The Synthesis' . of these

è substances:with rextremély 7 different' chemica ,cOmpositints:

is li.eedlesS to mention' that at the predent tinie the Secretion'

• Mechanisin• of' thi:s hormone iS unknoWn; hoWeirer,' Pri the basis of paSt

resea.rchea; -' it aPpears ,:that the -.secretion . is' regulated bY external . and

'internal etivirnnmen.t,, ..espeCialIy the reverse - action of the sex steriod

in the „ovary (Tàvèlga, 1949 , Egami, '1955) - , appe.ars _that;' , the

Yolk formation ,in fiah,„. 'àa in the case - of maturation in , màMma.ls, is

regulated by the - descending ..reaction of the pituitary gland and the

ascending action due to the sex steroid,: and that the interbrain hypo-

thalamus plays an important role as a nerve' centre.

Ovulation: The term ovulation refers to the process during which

eggs, after completed yol k formation, fall into the ovarian cavity, or

, into the ';coeldnia;,. throngh'céll follicle-layers; the eggs in the:same

stage of maturation are akibrated' -at the same':..time. '':Ovulation in many

CaSea:: SeemS: -to take . plane , d.uring: the night. Ovulation in as in

: the - case :of Vertèbrata, is mndôùbtedly. under the c.ontror of the:pituitary;, -

,giandS. For instance, .-thè - temova.1 of the pittiitary and from a mature . _

iSh f;COMPIletely' supPteSSeS ovulation, while an administration of pit-

uitary gland of fiShrestôteS:iit - 1941):. At the ,,present' time

it is not known if the pituita.ry gland hormone, i:cn -: . necessary.

, ovulation, ' is *different in .Charac.tér from the . yolk-formation--stimulating--

,. hotinone- (ysii); this is becanse' Of:- the possibility of ol...nlà.tion_ being

induced by the variation in:quantity of .VSH: However , as was pointed

out by Ball ,(1960), there is greater possibility of them being different

i956) , -repor t ed . although -néither-'FSH;:PrôlaCtin, nor ACTH in mammals

2

there is -a,'report :1960) to: i the-effect

that in fish . the ,.yolk7formatiàn fundtion of thé pitu.itary gland

a - decrease immediatelY Prior to ovulation, ,:Whiie there iâ no cledrease

in the ovulation inchieing-fUnCtion even. :after oviposition: . 1",'urther, . .

.hae no i...'effedt,,,Pn.Y .Olk . format-

'ion,

. . . .

s injeCt,ed into the coeloma of goidfish düring the oviposition

eriod when its ventral section is protruding, ovulation takes place

Within' 15-22 hàtirs Both sinahOrine and gonacitrôPhine contain .,:placental-- :-. . . .

.éex-glarid-Stimuiatirighorniâne j (HCG); this hormone reagent,:wae effective

, .against the iridiVidual , :froni whoni...the pituitary, gland had 'been. removed.

ié fact seems tp suggeat: that the hormone reagent acts d.itectlY,Pn

the ovary ; and induCea. oVUlation.. 'It is "'gimp:7n. that HCG is effective on

the ovulation Of .:.6:ther -speCieS of fish .euch'..àà ca.rp (KaWajiri, Kawakami,

1948), .(kirShenbla.t 1953), catfish -. (RarnasWaini and'Sundararaj ,

1958,. ,-CIénieria and S'need; 1959), and gilthead (Eibiya, 1962

On the Other 'ha:rid the phySiorlogidar .adtiàri of HCG resemblea that

. of LH mammals. in - mammals it acts on follicles and induces

- OvulatiOns. Witadhi. (1955) reported the- presénde of a corisiderable,,aniount „ _

actors in the pituitary. gland of salmon'. and Lepieosteus; Kiréhenblat

ad; an :effee- on ovulation, ,purified LH had the egect of indudirig

ovulation, even in individuals fràin Whont thé .pituitary ;glands had been

renià.Ved . 2(qt.toted , ':,frôm ;Ball 1960) n the 'iight of theSe fïridingé,- it - -

:appears that - . thé ovulation hormone ,of fiah, hecessary for ovulation,

reeemblea LH i,n Manimais, and that-it ié a , hormone whic-h is completely

Oviposition: Oviposttion reÈers to « , the phenomenon . where in eggs

Generally; .ovulation in 'fisk.does n.ot occur natUrally after - thè

coApletion of .yolk formation; but in -many ,.. cases it occurs as the .cresult

of changes in light, water temperature or quality of water , in addition * '

o external' environmental :stimuli such as Pla.ce: of- oViposition or, 'Stimulus ,

caused by the piirSuit by males ..: - Tints, it -appears that eXtern.al special

stimuli are .necessary: for thé 'secretion', of ovulation hormone and that •. .

thére is:a time lag . bètWeen secretion and actual. Ovnlatiori.

described above, it is concluded that ovulation is caused by the

secretion of , ovulation hormone from thè,pituitary gland It is .an

extremely interesting question whether the ovulation is caused by the

•'aptiô=i - f: this' hiJrniorie eione or bY a coMbine& action with other hormones;

The a.nswer ,must await.: the results ' of future -.research:»

which are in the ovarian Cavity or in the doeloma_ are expelled frOm the . . . ,

- body :bY. - bvipciSitory movementa charàOteristic. of a species," to -.enable , . • . , , . - - -

"eggs:to bs.,fertiliZed......-:A_phenoMenon . inwhich:ovipdsitionis.:-.SuPPresaéd

y an unsuitable oviposition - site or by a lack of 'Males (even though

Many .eggs, 'after' having been ovulated; are found in the ventral section

phénoMenon whiCh is often observed in fish farming it is interpreted.:

as being- . due to ' the fact : that 6Viposition.' belongs '.to a mechanism:, different.

from ovulation.. -

; It appear's tha t:the endocrine ' systeM, including the hypothalmUS,

the. pituitary,' gland and the sex glands, - is asSociated with the chara-

cteristic sex: moveMentS which acebinpanY. Oviposition.. For 'instance : it

is reported that, if the ova.ry is removed in Hemicromis, the sex move-

. Merits are coMplètely 'suppressed' (Noble and kuing, .1936), and that in

■ 1

essuniiiig laty fish, the administration of estrogen results in males

ovulate : mature eggs-are artificially squeezed pliti - of the Ovaian .cavity

. of goldfiéh "6VipbSitory,-a -ctidn' is not àésumed'.evén f;vhen -puréned vigoi-Ousl

:a•j;.;.à11:àiààçe

bbserved - a similar action

ion Fund.ulus and in killifish on inj,e.ting, them

with posterior d f the pituitary gland It was further ,. ,

reported (Egami 1959) 'that when the hormone was injected into a kiln-- ,

fish which was ovul.ating, ovi.position took place.' Recently, substances

resembling ÔxytoCin ..Vasopresin wee -,:detected- Ohémically..,iii , the pituitary

,.,Vations:-Suggest . .

emalés • also there:" is- à relation .betweeri. spawning

neurOSecretion, - Originating - _ from ---the secretory nucleus .:of...'the: hypothalmiis

in the Case,. Of ',.hYP6thalmo:-pronucieus 'fish ••(an.6; 1963) , paSses' through the

-pituitary passage of the .hYPothalMiie and is aCCUMulated in the : poSterlor

lobe . ,rePorted. (Aronson., -1957) that , when the hypothalMus is dam-

aged , in males e:sexüel . mbvèment is coMPietely suppressed. These obeer-

action and hypothalmo-n.eurosecretion.

Conclusion : The -above. observations on maturation and oviposition. , in

Us to the conclusion that maturation is regulated ,. by two different.

"sex-gland-stimulating hormones from the Pituita.ry gland, i.e.-, yolk-form- ,

ation-stimulating hormone and ovulation hormone, and t a , -

osition is not directly control ed by the adenohypophysis there is

some relation betWeen'- it - and the secretion :=of-; - the .posteriorlobe hormone

of the hypothalmus At the'spres.ent time these :hOrmones, and ,eapeCially.

, hOrMOneS: :related •*.- to maturation : haVe . not been eXtrected chemically. :Thus,

nothing is known‘. :Of the chemicai composition of these hormones or, t ear

. epecific characteristics It seeins to the author' that the chemica , • - • • -. .

-:separation. -an'èxtraction • of effective components of theliPitilitary' 'gland

necesàar 6 nekplain' the mechanism of 'internal .sedretion

:6É. maturation and oViPosition''iri fish and to establish methOds to_.", stimulate..

.Maturatidn - ;in.. - fish ..by-.. the administration 6f horn:tot:Lea . •

igh .ifiCanCe'of

e 'main ekternar':envirônMental : factors 'Which affect maturation and

spawning if f ish are believed to be - li'ght and temperature. ,In addition

environmental faCtorà.isuch as ,the .amount of. water flow, height of

'fwa:ëaï-. ; and the Characteristica ..iif:,: •bed and mutual stimuli ,eXerted; • by, fish

are conaidered in relation to spawning action. ;Fur , her, since the:size

d th' speed of '..gro‘Wth Of . fiSh affect the .maturation of the :gona , one, - - * - may r in a Wider' sirise the 'quantity:and tile- .qnaiity of feed"as

rexterna •

Various experimental researches have been made with 'respect to these

that t: eXP'erijiiental 'r.èaearChes . .,'..on . the régUlatibri.',Of

, and-.probletas .on:the.-regniation , 'of'.épawning','due to these factors : as 'carried:: .... •

at the present time with cultured fishes such as rainbow

,-. tront,and'•'.'sWeetÈis

nyir:onmental : factors and maturation and _spawning in fish:: A.:: Light-

e, Strength and the quantity à: ight plays an important role in the

'maturation of gôna:Clal - and. in spawning There have:been many studies in

which Changes in maturation and spawning' in fish . wère induced' by art'ific-

such' SiSeClea .: as 'sà.1Mon, trOnt or sTeieetf ish ' which Spawn . in the 'f ali when

ays.are, shârter, by"shorténing the da.ylight hours earlier than.under.-

Stati9ñ '59-62, Shiral.shi, Takeda '61). 1.71

KaWamura, Otshka 0 , and

natural. conditions, and delayed- by reversing thé procédure -.(Hover

Hoover .and Hubba.rfi. - '37; Hazard and Eddy . "-51, Allison '51,* Burrowà 58,

NOmura .157, CoMbs, BurrowS''and Bigej s' 59,-- -Nomura '62 'Shizuoka Exp Station -

ith.Traspect *to.. spedies - which spaWn frorri: spring to sumriler . (stick7- _ . . ,

ébàck 'Shiner, , SiinfIsh goldfiSh,. and others) : .contrary to the cases o

rout: or sWeetfish, -Maturation _and - :,Spa.wning. is advanced .by lengthening the

àylight hours more than under natural conditions in an earlier '-period

.(fall Or , spring)n'(EEckhoudet

'.others). ,Killifishes spaWn shortly before dawn howeyer, if periods--of -

light and .dark .are reVersed; ., they spawn shortly before thC ,artifiçially

inducecl light period (Robinson and Rugh '43, Egami '54).

è.'exis-tence of claY:light honrs, which are 1.i:egesSary to adVanCe-- ..or

delay maturation in fish has been recognized in killifish and sweetfish:

maximum of :1 in both àpecies, maturation is advanced or delayed by a

'hours (Yoshioka Yamamoto '63 àhiraishi Takeda. '61).

There are 2 or 3 reports which.' state that the methods Of changing

daylight 'hours - havé different effeCtS' on -MaturatiOn. In the female of

stickleback-, when the qua.ntity of exposure per day is fixed, discontinous

exPOsure is more effective than Continous expbsuré (Eeckhoudt '47);

, when *daylight was shortened' . ti5 a ;fixed time,'".the egg-extraction. (?

peri6c1 of sweetfish ,:was more -advanced if- daylight was shortened, gra.dually

ovér a iâng-period than if it waa shortened at one time . (Gifu Exp. Station

'63) ., ::.Eurther'' Hazard , and - Eddy in their spaWning,stimulatirig - experiMentà

with Salvelinus fon.tindis (Éitchill) fouhd that the effect was propor-

tional to the change in the quantity of light.

t is -khoWri in - somé species that .Sensitivity to light differs by

_ . . , SeasOn and-hy the stage o , . -

maturaticin, of the fie (Harrington-

Rasquin!, . .

Rasquin and Rosenbloom '54); n'éweetflah, matüratiOn...of,..the ,

. „ .... . , .• • . • . - than- 6.n tetilperatn.re: ,.,„•,.. . • . . Breder

,

Mc:Namara

Atorïéo'±i';:- : ! sr, ,

11(5Wever - in fish the receptacle

the eyes; - it is suggesteà that

7

• Bn1.16.Ugh»...'.3.9)::.. n such species the 'environmental _factors ::reqnired .differ

dePending. :.!Ori the •StageT•Cd .,[deVelOPtént: ofi:gOnailà% and the maturation does. . . , . . .

. . . . . . . ..;-nét-,•advançg- unléss.,..the;,requirementé.. are -met

-"Experiments to in:Yeet-e-te'' the effects:;-of, light by raising fish,;. in

the dark oVer ..a long period are conducted, ,friainly with warm ,water fish.

n thèse 'species the .gonads generally degenerate in • the dark ,and -. there is

also a 'change in 'thé tissue _image('?) of the pituitary -gland' (Ogneff ." 11,

onads is Stimulated Takeda .62) .

With respect to local variations in the spawning period and to the

1.)eriodi.bity reproduction under-,natural conditions in the same species,

'explanaticina have- bèen offered on the basis of .the effeOtà of the length

The route which the light stimulus takes in '..a.ffèdting ..the gonads o

- - - iàh haa.-not. been -eatablished -; hoWeVer, is believed' that generally

takes the p_ath . eye4brain--->hypothalamus->neurosecretory ceIls-> pituitary

gland-,---> . gbnad (Turner. '37,;', Hoar 56). , .

for light is not rieceSSarily limited

light directly, affects the-brain, or that the skin- is sensitive to light

f(Payne 07, Bullongh' Resquin' 49, Rasquin and ,-;■Rosenbloom.› Pickfo rd

and Atz' ''.57) :Further; it is believed that . the 'pineal, body also acts. _

competitively again.st the pituitary gland with respect to light (Young '35,

Breder.'and Rasq'uin ..:' 47 . '50)

Temperature: There are also many research reports which claim

eiriperaturé, rather than light .tO be thé main factor in the regulation.; o

the upper and lower limits are known for some species. (Lewis Leitritz

28

maturation .and spawning in fis ,(Crai B n et --31, Di dine .. 36, Matthews

'Hora, - Mooketjee, Khan, Husain, - Das and Dasgupta 45, ..Medlen 51,

-Lillie and Kirk:, '51' e relative imP ancsepf:,. light and temperature

on maturation and spaWning of . fish .depends on species, degree: of mat

tat i'orks,.••ot,i;Seado .n':'(FabriCiti...." .0 '39.)

Generally,' in warm water fishes maturation is stimulated by higher

‘,tempetature;.--.1ow tempetaturé adtS inhibitive1y (MatteWs Bullough 39 . ....,.. , . _ .. • - . .••• - •••._ • . •• • ,. ,.;• ., - , ., .., , ; „, • . . .. .., „ . -. - . _ • › , .,.- -, . . .: .. .., ., . . : . • ..

: reCren.: . '3I),:,:. '.: 1 -In 'cold wat,en•-fiahea,l' . .a. reVetse.:-phencimenciri --ie'..obSetVéd .:'

-',(12by,dé.::' -.51;.::Saitama. F.Xp .'...iStatiOn:,'5861,.'•Nbintira.:''62) . ..--2 . ''-''....-•,: - .Y..... - ..•. ...- . . . . ... .„. .. ...

For - normal Maturation ,and spawhin.g .and in order to Obtain eggs' of

good quality, 'a . fixed 'range. ,-of temperature is necessary for each species;

0, Miya.zak.i-Ken Tansui Gyo--gyo Shidosho Miyazaki-Ken Fresh Water Fish--

erieS::.Gtiidance Institiite' '6 1 , 'ITC,imUra '62'; Yoshioka '62) This range Can

be ekten.cled... by. the administration of • hormones (Pickford and Àtz „ „ , • "

hçiweverr, if the .:•temPeratilte deviates tôô fat from thiS range, the - effeôt ,

of • the >administration of • hormones becbMes •:difficult tb detect :(ÈutIét.

The route-'which• the temperature- stimulus taks to affect . the'goriad

• ' .• • ' ' ' • let.•of light Although there is

‘,ink;2.; _ . . , . .

eMpetature the:PltuitatY:plaYS the most important role, it is

nbt 'Yet ,established whether, in poikildtherMal ani'mals such as fish,:'-the

temperature àcti directlY on the pituitary. 'gland function, •Whethet it

Causes :change in the central nerVous stimuli; - or whether - it affects the

on.ad direCtly:,'(Pickford•.and Atz '57) .

. Other -,-external stimuli In addition to light ..and '.temperature',-

other .physical and chemical:factors such as the - amount of - oxygen dissolved

eight -

6Okerjee'-' 1 '14-5-IiidtiCed spawning in indian carp by increasing the amOunt of

- , oxYgen:- .water. In many speçiès of fiah epawning' grounds -are, ,-rela.tiely,

'fixed; de:Pending:: on such.' .;-factors ,: as -depth .--iôf -water, quality of the bOttàm,

aquatic plants eiicir,:the::',Prèsence of shell'' , fish, are fixed It is belieVed

_factors .or -in„ COMbinatj_On. are reepOne ible‘ for lriduç:ing

spaWning. ::: -FUrther,' it .' is 'Observed .. thatiin . euch apeCiee as '-gbldfish and

- • ::• " Tire:pia:the eight Of.Other,.-individuale cif':-the:eaMe.'Or:OppiOaite -.'seX-Or

àffedcsË-ril;ri ;An:it-won (Ka:We:Mitt a Otsùka ,„.

n 'fish there is :à close relation between' sexual e

and the - siZe-or-,..the. speed: Of grOWth of fish. Alm '59 made a detailed

studyy-and..répôrted on thie -prOble.M.- 'Hie restate. ehOW that in the eaMe, a e

grotip ,- maturation is more- advanced as the "size ,VfeCoMee larger, ;- and- if the

initial_ grcreth is:gOod . the fish'_Matures s.at a younger age The author 63)

acussed the develoPMent of the :gonadé and the size, of the new y- orn-

fish in 're.d.AbOw. trout- and reported- that witb.in:.-the -- eame age : grOup: maturity

- 'the eize •becairie la.rger tha.t ---, when:fish are .Taisecl ., :wae , more , , • : , tol :MOre than •500 -2....g,..--eggs çailihe:obilected‘''.froM"inoat---,of the fish: at

full years

erierally; ,When foOd+intake::is low, .the proportion

in the'' ovary., iricreabes (Scott '62)"; ' , On -, the other

o

'hand ; an ' - inCrease : ' in the food supply stimiilates maturatiOn . of the gOnads ,

:inCreaSes s the ',quantity ofieggS. per fish,' and increases the rate lo

tilization in r young ferules (Nikolsky 63) . . .

:fer-

- 'There -iS réPort dealing With' the pielity of feed, accordinÉ to Which

the administration of feed with .fat • cc:intent, before spaWning brings about

a condition of sterility in fish 'depending on the degree of o-vereating

(Buschkiel '.38 ,- arkL,others

There is a report dealing

Regulation f SOY:aping in chlthred .fiSh: by environmental factors:

,t the present time reàulation of the spawning (egg collecti. on period

in- thià country is :done. by Means: of -light :and.-temperature H.treatu4nt ..

species are rainbôx:a tront and Sweetfish.,- *.

The - water temperature ‘of the .experimerital pond 'at the KuMagai Rain- , .

-

The

OW.-TroUt-Chithre,Station in Saitama-Ken was 14-18-C even in winter; the

sPa wning period of rainbowtrout was Jan. -Mar.; however, only eggs which

could not be fertilized. were obta.ined. By providing a circula.tory (?) . .

pond the winter-.Watér'teraPerature was brought doWn to 8-13°d .., .the Spawning ,

Period . 'ça'..as' advanced to Dec*4 - and the fertilization'.rate was .,

raised to over 80%. Further, by transplanting the parent fishes to a place

.i.;:ahere;- the :Wih.ter'' .1tiiater,...teMPerathre.iiS less--:.:than.5 9c,- the 'sPaWning. period „. . „-. , . - . • . • -:. . .• ,

s:.delayed .fto:'-Mar.. when..water temperature. begins - to .,.•rise(Owatari - '63)

Regulation with light is being tried in various experimental stations

n Gifu, Miyazaki,: ToChigi, Gunma.; and Shiga; attempts have:been sucCessful, - -. _

in'adyencing,the•: spawning period by 1-2 months.'or , 'delaying: it to Mar. in

the nékt ':been cOndiaCted:',Y,aith rainhow trout in

experimental station in Shizuika, Nagano and Tochigi; they advanced the

egg-collection-.:périod : 'by 1 -' 4 months.-

he 'rate 6f 'appearan.ce of -.eyes and the growth after hatching -`of fry -

„rainbow trout, obtained from the eggs iahich were trea.ted with'light,

not shoW:'any , 'differenCé to thoSe :obtained ' Under natural conditions,

bweVer-; in 'sweetfiSh with the. exception of the Gifu Exp;; Station, only

.-,egge, of inferior quality with extremely .low rate of eye appearance are

Obtained; - fUrther eggs of the Gifu:Exp. Station produce young with an'

extremely low rate of sUrvival after . hatChing . in cOmpariSori to those

which . are collected under natural conditions (Ito: '63) .. Further,

both species the size of eggs is smaller in comparison to those obtained

under netural conditions.'

In- fish - culture, it is necessary not only that _eggs- be available .

. early but also that eggs and the young be healthy. : : For this it appears

, that 'One .,:must çon.sidét,' alonfg with the change in daylight hours and the

_ advance in the spawning 'period, the seaSonal distribution and qùality of

pérature. - Further, one factor in the pcior ; que.lity

of eggs in the case of sweetf3_"sh- seems to be the fact that the conditions

as to water temperature are not met. Further' ,althongh it is important to

aim at high efficiency an -.édonOmY.: in light: treatieent byc aliOrtening . the . . „

period, Of:light treatment, to attain these aims it will also be iàecessary

to investigate the type« and the . strength of an effective light ,source, the.

variation in quantity of light and attendant method, and- the time and the

duration of the light treàtmen

oo, agrouP Made of sUch:rpedpIe as HASLER, , - -

Technique of adminiatering hormone and ,ità'effeCts..

Kyo Hibiya (To Dai, Agr.

n 'Outline: 'Stinnalation .-of Maturation and ovulation :àne to:. - horniàries:

In - • Ël_eh as in

ls.th ma tthe uration n .Y on

_

of the gonads, both in male and female. Attempts to artificiall y bring

about maturation of the gona.ds and to stimulate oVulation - bY administering .

thel .Pitetary gland, -homogena.te, or GTH' ektracted frOm it, had its

beginning.., :in.: the :.sticoess He succeeded in cansing, ovul-

ation one half .M.énth: befbre.--thé natUral 'repiroductiye, period and 1 3 days

af.ter. injecting an ,extractive from fresh pituitary. glands. of-Prochilodus

-:platenSis and other fishes -intor the ventral , Ca'vity of Cnésterodon -decem-

maculattis-. This -Succesa stiMula.ted .similar,,attempts in other cOuntries:

•• • • ' • ' 'Howe-vér,- the lead.ing countries:, n this

"''•.' ' • • ' • t - wcirk":'Weré''Bra.' the In Brazil' researches were- , carrid e

to Cause spaWning ,in fish' kePt.' in a culture pond; in the USSR .they were

-.carried out to raise' sturgeon,- and to bring about spawning in ponds o

sturgeon which had een prevented from going uPstream on account of dams

PICKFORD, - and :ROBERTSON; advanced studies in...this. field and :realized ,

„sUcçess, froM, a practical standpoint in treatu.ng .salmonoid f.ishea with

ituitary, gland. in 'Japan, -Sinée KaWamura.' ,( 44) a.dhieved succes s -. in arti-

fiCial ovulation - of , loaOh- by ..-an injection of antérior-lobe-Colliiidal ,

adspénsiOn of 1:n111:frog, administration of pituitary:glandrcblloicial-, ,

SUS'p,enSiOn or of hbrniOne.'eS* --.:a..ttemP•ted on OtiltUreer'-',fishea sUch as carP

'silver carp,- 'goldfish, rainbow _tront, salmon-trout,-: eel,' and gilthead;

many succesSes have been reported. :With respect to loach the Methcid has

een establishe tentatively . n addition, in .various countries: in

SOUtheaSt Asia :tiiése 'techniques are -actiVely

33

Types of effective substances: There is an extremely'. large number

examples in ' ,Which fresh :pituitary of fish or its :suspension, in phy-

SiolOgical Salt Solution was injected into muscles, 'ventral eaVity,.or

tinder the .Skin after dehydration with adetone , and pulverization In ,

is• case, an 'exaMination of the 'relation between' ,:the donor ., and the

recipient shows varied mixtures among - the same.:species, same gonus (?)

gr same family and eVen among unrelated flail: There are 'niany casés o

the donors not beirig f.iSh '.aniphibians Mainnals' in other cases _ .

eéruin : from pregna.rit mares (PM,S) ,, .urine from pregnant Women, (PH):: Or •

pia.centaI hormone (CG) is usèd in.stead of the :pitiiitary. -

srornigrie r.igagente•'...,which-aTe., tefitiedi , :froni:.0TH-rextracted. , .2f.rOni . the pituitary gf:CoW -;;•..horSe; pig , or sheep the 'Serum- of,iftegnant:•:Mares

human placent ';.;,' . or Urine :'frOni.:,..:,p,regnant women , are .: Conner CiellV available

In each case;..:'the pnritY, clOeS n.Ot- :seem to be high it i'a -p'ieSuniecrthat

gonadotrophine, pubelogen (9), and gqstr-on, have a strong,: LH . action, f

,Cerotropliirie.:.:(1.):;,•::•pernexC.:Y;',-•-and,;;ceralinoriè a strong FSH action; ,-- and,f'Sinahoring,,.

, gonadoPleX ;•.-; and pétrophine.a:..atrong comb.in.ed action of ther:afore-Mentioned, . . . , . • . , ••„ . „ .„ . . „ twb.: Or iginaliy, these were intended for .-sexual .' impotence in-iman and

catt le and for varions ailments related to 'it hoWever , several of these

have -• already beeri:used With sucéess to stiMulate-Maturation' and ovulation

in fish.: - -However, a glance ' at the results 'show that • - the - ekamples . of • "

-ovulation . and spawning- are :many but those of - stimulatin.g maturation of

ovarian eggs are few. _ -In . higher vertebrate mainly FSH participates - in

the maturation.,,'process of follicle- and LElifuovulation; if the processes ..

hormone with a- large quantity of FSH:innst be effective in stimulating thé prOcess of d.evelopment of odCytes. HoweVer, a.ctual

results do not necesaarily indicate this This may be related t the fact

that the •IiituitarY of fish contains a relativelV .-large quantity .of LU • and • • , that FSH, is donta inèd to the extent of '-merely 10 -TO of that in mainnials

as reported:by Witschi, .• There are a. fev.T investigators who. deny the _ , • •existence of FSH in fish. There - are examples in which GM was Used in

combination with Sex hormones -: .•'‘ These will be dealt with la:ter sections.

the digestive enzym vneedless to say:.that the resillta Were.-poor.

With respect to the induction of spa1ng, In the investigation by

rilhelmi et al ('55) an injection into the 'ventral Ca.vity of Vasopressin , ,

and "Oxytocin , • hormones from:the 'posteriOr lobe, ,caused.an-iminediate

spawning-reaCtion.. Egami. (,',61) suggest s . that in ki.11ifish the aecreticin

Df hormone from the ,piosterior lobe is - stimulated . thrOugh the nerve routes

- an‘èU tliat when :it...réaChea .'theiSeak -,:'7 sPaWnitig:'-takes:-..Ple.Cel.:'".Fn' rther',!:

awamura et. al' (.' 5 0) repà,rted. ,, that sufficient ovulation took place. in

émale goldfish - which:had ,been injected With :colloidal suspension of the

anterior lobe when t e male was provided unlike the case when the male

:Methods .:ôf adMinistration,'of hormone :: There is a meth° -,in w ich a

itnitary is transplanted in to the muscles or in to the ventral cavity

r a :method:in which. effective Substances are made

into pellets and shot into the muscles by .a pellet injector. ' However

adtUal:-2eXàMplea-: -of:#PliCation:are..,few:

„ e; CoinMonest Method ia the injection intà, muscles or the ventral _ _ . .

..pension:. In physiÏogLI: st

olutiàn bf:pitiiitary - whiCh had been crusheRr'àeter' 'having' heen, , desiccated

'53) f 11 th 5 o owe e mi

faVbilrablé reaulta..:,by the ,:use of Colloidal suspension - of pituitary with

iirther; . 1<nbota (1 5 3 ) 'atteirtpted tà :feed:, the pitnitary with -fo6

Further:, 'HibiYa et _al ( -63), by a concurrent- injection of sinahorin _

and vitamin. E, advanced the Mattirationof . ovarY in eel - further than when

t is suggested that this was due to .the fact . .

sinahorin was used alone.

that vitamin E stimulated yolk formation thrOugh the pitu.i.tary of fis

Judgment on the effects f administration of - hormone : Generally; the

. • effects of promotion of maturation is judged by the gonad index which is

, , , - • -

based,, on the Weight of the gonads • however. , the resillts will be confirmed —

certainty, by an examinatio n of freqUency. distrib-

ution of - the egg : . diameter of - 'oVarian'• egga and by„ an Observation of tissue

spec.imens of ova.ries of striped - loach which vhecl, been treated with col.loida • • - ' of pituiterY• of bUilfroi . , and he made detaiied observations : o

é s.rinciar''pha'së' . of , : oocytes and of the condition of .- yolk granules, - •

check the effecta of the.: treatinen

- flecéasary. -to ',-observe not . oniy, the 'effecta on the'‘ promotion -

e..r:euth6r

--:,abriditiOns are • caught:: and the are -CO.liedted - iininediat,ely' on tha.f.,aeene',..' . , . •

:•traria'POrtad::;.éOnie' :: .diâtance the rate is markedly iëdUê. aFci .

The failures have been attributed to the mature 6ggé during

the handling. Of fishes or ,tO•' -the injurias 'sustained by the fish iloWever,

it .-shonld be noted that - Forster: ( ' 53) and ôthers,:observed-. , that, When

fishes . Were caught ontdoors and :cOoped .. up in a 'small spa6e,, an unnsual

diuresis 'phenomenon.. took .-plate. , and there' was a: :marked. variation In the

ExaMination Of donô erbilskii ('38) laims that there is no

(.31, "52) points out -that the- pituitary of, -carp . iri ;Winter' ita.s no prU-

motional 'effects on the maturation of the ovary. On the ,basis of the

.seasonal variation :in the: Cellula.r composition of pittlitary, it .is clea in the cellular composition of pituitary, it is clear

e maintains tha.t there is a special

feWer, occasions than _ . ,ve them freqUeritlY,

36 •

osmotic pressure o

ï_on ..in > the ntimber '

body fluid and in salt composition; thus, the variat-

, f eggs-collected. may be ClOsely related to thia,.phenon-

en.on, 'which. Forster 'termed "laboratory diuresi.

sexital sPecificity 'between the donor and the -recipient; however; there

are-other research workers' who take the opposite .stand. Ftirther, stand. Further, Kazanskii

tha.t :ite ,promoti6nal effectS: Will - Vary dea.—aonall#: . „ _

Kazanskii hormone: Kazanskii ( '51, '52) compared fresh pituitary

stickleback with one which had been dehydrated-with a.cetone, and found

ovary of individuals of the same species, the latter had no such effect s .

also found that the effective substance was present in the pituitary

the-

,;a:bserit : fieh.;'whiCh f fish 'during the 'spayrning: : -Periodi;: but that „ .

-,had peé .sed the spaWning period,

hormone in the. 'pituitary.'of - is fish 'WhiCh appears tOwardé, the spa.wning period

and which promotes yolk formation and is espeCially sensitive to .acetone.

'Whil& this oPinion agrees iri. sbnie respects With:opin.ions and observations

f many :workers; it laCks :SuffiCient auPpôrting eVidence ,

itântity and interval' adMinistration:.:Britrin. et: al ('49) found „

that when ..pleCental : hormone and synthetic estrOgen are injected into eel,

è two in a large .qua.ntity

sMall: doses. However ,

the -egg diameter waa.bigger .than when GTH a one was injec e . inj ected

indicated , that it was more effective to Ihjedt these :two'itt

only :placental- h6rmOnef o be giveri : is better to give • small*

doses -.:Irequéritly. The determination of d suitable a.ritount, in.terifal,: and

administration of hormone is a difficult problem. since the

's9'Steiti :rélatàd' tb endocrine

olatiOn:, Of , fiSh, thé- ie a danger thettheï'esUïte Tj111:»he':* UrifVoiirabile . _ .

Unless" the quantity is right „Wh_eli : the ,ehoV,,e two hor,monéS. are use . . . . ,

- 'siriCe'estrà COn' OUrrentl'i ,:it. is •dan_eredis -- to shorten the :_nterye.l. eStrogèn- ,sup- ...

There 'have een discussions ence' about 1939

With teferende to thé; presence or a Sence ,, of thé. speCifi& .Spëcif icity. o

however ., It ',È.pPear s'

YWiththëinrdteaSeirithè;amOunt

as the technique ' Of hollitmadmiiétratiOn .séces:SarY . quantity

the btherhànd. .the: sùctura.l foMulee sOme ..horMones' 7.Sich..aS

-éCifi'oiti's 'beginning

héMatütatio#. Of ::the:,:gOnad -si'S-r, sUpptesSée.by- repeate - injections Ho

TH and Whi ch the GTH adtriiiirStr ..ed'bedoMéS -:_ântieen':;...ând ;.daiisës-:tW

OrMatibiu of..*ant ihorMone. is being d1scusSedï

1

References for (4);_ Environmental Effects on Maturation and

pawning of Fish.

- Symposium. on rearing of Ipareht fish, with,'specialreference_

: T -the-control_of_MaturatiOn:and spawning.

• . . .

Significanc e - WI. of environinental -factors - suCh as - light-and-

its application

Allison,.L. N. 1951: Delong_e_spawning in eastern brook.

, 1951: Factors influencing the spawining frequency . T

in the female cichlid Yilapia macrocephala, Amer. Mus. Novit.,

( 1484 ) : 1-26.

1957: Reproduction and parental behaviour, The phy-

siology of fishes, Vol. 2, p. 271 -304. •

*4)

=' trout by means of artificially prolonged light intervals, P.F.C.

13, 111-116.

2) Alm, G. 1959: Correlation between maturity, size and age

in fishes. Inst. Fresh w. Res. Rep. 40, 5-145.

3) Aronson, L. R. 1945: Influence of the stimuli provided by

the male cicklid fish, Tilapia macrocephala, on the spawning

. frequency of the female, Physiol. Zool. • 8, 403-415.

6) Breder, C. M.:1936: The reproduction habits of the North

American sunfishes (family centrarchidae), Zoologica 21, 1-47.

7) an4 P.Rasquin 1947: Comparative studies in the light

sensitivity of blind characins from a series of Mexican caves,

Bull. Amer. Mus. nat. Hist., 89, 319-352.

8) and 1950: A preliminary report on the role of

the pineal organ in the control of pigment cells in light

reactions in recent teleost fishes, Sciènce 111, MI 10-12.

9) Bullough, W. S. 1939: A study of the reproductive cycle of

to the environinént, Proc. Zool.

Lônd., 109: 79-102..'

194.0:A study of sex reversal in the minnow (Phoxi-

1942: Gametogenesis, and some endocrine factors affect- _ #12)

2 fn

-1-

,e)

e)

References

mus laevis, L), J. exptl. Zool., 85: 475-499.

11) 1940: The effect of the reduction of light in spring

on the breeding season of the minnow (Phoximus laevis Linn.),

Proc. Zool. Soc. Lond., 110:149-157.

ing it in the adult minnow (Phoximus laevis L.) J. Endocrin.,

3: 211-219.

13) Burger, J. W. 1939: Some experiments on the relation of the

external environmeht to the spermetogeneti4 cycle of

Fundubus .heteroclit ( L ), . ,

-70 - 14.) Burrows R. E. 1957: Acceleration of spawning of adult sal-

mon P F -C P 75

15) Burrows, R. E. 1958: Light as a factor in acceleratiéng the

spawning of blue back salmon. Prog. Fish-Cult. 20: 57.

16)Buschkiel 1938: Grensen der Vererblickkeit von Karpfenei-

genschaften, Zeitschr. Fisher. 36: 1-22.

17) Cloudsley-Thompson, J. L. 1961: Rhythmic activity in ani-

; • • §

I e -L

mal physiology and behaviour9

,pp. 1-236, New York and London. fg) C o;IrIs &D.? ite s iderDtetiG ..t, R4-,(5 ■ Cieg4qcq ■ -11\e- d -P-Ça0.4 oq c,„›.1r.o.e.4 he 1s) Corsod, B. W. 1955: Four years progress in the use of arti-

ficially controlled light to induce early spawning of brook U.ét

trout, Prog. Fish-Cult. 17(3), 99-102.

20) Craig-Bennet, A 1931: The reproductive cycle of the three-

spined stickleback, Phil. Trans. Roy. Soc. London, 13. 219:

197-279.

21) Egami, N. 1954 d: Effect of artificial photoperiodicity on re5

time of oviposition in the fish, Oryzias., Annot. Zool. Jap., A

27: 57-62.

22) Fabricius, E 1950: Heterogeneous stimulus summation in the

release of spawning activities in fish, Inst. Freshwater Res.

Prottiningholm Rept. No. 31, 57-99.

23) Furukawa, Yu 1962: Winter rearing of sweetfish , 35th Lake -

and River Culture Research Meeting Di4g4s, 57-99.

24).1Gifu-Ken Fisheries Experimental Station 1959: Study on prod-

uction of $weetfish stock (Report 4) , Growth acceïeration ex-

perimant, p. 1716.

, .1961: Results of experiment on growth acceleration ex-

R. E. 1950: Modification of the sexu-

Amer. Fish, control of light, Trans.

33) Hoover, E. E., and Hubbard, H. F. 1937: Modification of the

a

3 References

periment of gonad of sweetfish. (Report No. 7), p. 1-20 (m4meogra-

phed).

26)

Comparative experiments in maturation acceleration between _ . _ ,IMOn thé young produced in.sea and in Lake Biwa,'. p. 1-11

, (mtmeographed).

27) 1962: A study on the production of sweetfish stock, p. --

28) Grunewald - Lowensteini. M._ _1952: StudieS-- on-:-the function

the pineal body, Exper. Surg., 10: 135-15

1956: Influence of light and'dOrknéss on the pineal

body , in_Astyanax mexicanusjFilippi), Z0a) Zoologica,

41: 119-128.

30) Harrington, R. W., Jr. 1950: Preseasonal breeding by the

bridled schiner, Notropis lifrenatus, induced under light-tem-

perature control. Copeia,--304-311. -

31) 1956: - An experiment on the effect of contrasting daily

photoperiods on gameStogenesis and reproduction in the centrar-

chid fish, Enneacan-thus obesus (Girard), J. explt. Zool.,

131: 203-223.

32) Hazard, T. P. and Eddy,

al, cycle in brook trout by

$ SOC.'

1962: A study on raising sweetfish stock (Rep. No. 8),

80, 158-162.

sexual cycle of trout by control of light, Copeia, p. 206-210.

34) 1937: Experimental modification of the sexual cycle

in trout by control of light, Science, 86 (2236), 425-426.

35)# Hora, S., H. Mookerzee, H. Khan, A. Husain, K. Das and B.

Das Gupta 1945: Symposium on the "factors influencing the spawn-

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36) Hoar, W. S. 1953: Control and timing of fish migration, Biol.

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37) 1956: Photoperioclism and thermal

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resistance of gold-

4.

1956: Seasonal variations in the resistance of• s ,

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1926: Th4tractural consequences of modifica-.' ,

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and K. Strawn, 1957: The effects of light and tem-

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stone - lepidum,.Ecology, 38, 4: 596-602.

41) 7KaWaMura,2ChijirOland:SotojiIpuzuka :1950n :promotion of

ovulation in goldfish, Gyo Zatsu 1(3), 157-165.

Teferences

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:39) Hubbs, -C.. L.

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40)

_ . _ 42) - fawajiri, Minoru- Kyuzo Hata and »1›. Shigeru Murai 1930: On , _

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43) Kawajiri, Minoru 1949: Effect of group density on the re-

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47) Leitritz, E. •

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49)# Le Cren, E. D. 1951: The length-weight relationship and

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dulùs,

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50) Matthews', S. 1938: Thé seasonal cycle

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of eggs of 1--.ain.bow trout - IV, On the number of eggs collected, _

Sissui-Shi "29(4), 325-335. -

63) _1963:.- Fundamental studies on artificial collection:

of eggà_of rainbow trout - V, Development of gOnads and the sise

of the young hatched in eariier"period, NissuiShi 29(11)

References

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53) Medlen B. 1951: Preliminary observations on the effects

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54) Merriman, D. ,and H. P. Schedl 1941: The effect of light and

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55) Miyazaki-Ken Fresh Water Fisheries Directorate, Kobayashi

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5e) 57) Mookerjee, H. K. 1945: Factors influencing the spawning

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59) Nomura, Minoru 1959: On the acceleration of spawning period

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of spawning period by transplanting and selective,rearing,

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61) Nomura Minoru 1962: Fundamental studies on artificial collec- - -

tion of eggs of rainbow trout - III Acceleration of IçIeMutt,

collection due to change in light period, Nissui-Shi 28(11),

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62) 1963: Fundamental studies on artificial collection

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Anz, 40: 81787._

65) Owatari, Sai: private correspondqInce.

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63) Saitama-Ken SuisanShiken-Jo vdgyo Hokoku (Sait4a-Ken Fish-

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6

64) - Ogneff 1911: Ueber die Aenderungen in den Organen der

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66) Payne, F. 1907: The reaction of the blind fish, Amblyopsis

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67) Phillips, A. /101., H. A. Podoliak, D. R. Brockway and R. R.

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68) Phillips, A. M. J. R., H. A. Podoliak, R. F. Dumas and R. W.

Thoesen 1958: The effect of light, diet, and the age of the

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69) , , D. L. Livingston, R. F. Dumas, R. W. Thoesen ning

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70) Pickford, G. E. and J. E. AtzX 1957: The physiology of

pituitary gland of fishes, N. Y. Zool. Soc. 10: 1-637.

71) Rasquin, P. 1949: The of light and darkness on thy-

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72) and L. Rosenbloom 1954: Endocrine imbalance and tissue

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73) Robinson, E. J. and R. Rugh 1943: The reproduction processes

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• 10 (1959), No. 12 (1960), No. 14 (1961).

_ References

77) Samejima, Jitsuo 1962: On0 acceleration ?J. and inhibition

experiéents of spawning of sweetfish, 35th Lake and River

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78) Scott, D. P. 1962: Effect of Food Quantity on Fecundity of

Rainbow Truut, Salmo 4 Gairdneri, J. Fish. Res. Bd. Canada

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79) Seguin, Louis-Roch 1956: Scientific fish culture in Quebec

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80)$ Shiraishi, Yoshiichi - and Tatsuya Takeda 1961: Effects of

light period on.maturatiOnofeetfish,- Tansùï .Ken-Po - (Fresh

Water Research Rep.) 11(1), 69-81. '

81) Shizuoka-Ken--Fuji Yo Masù Jo Jigyo Hokoku (Shizuoka-Ken Fuji -

Salmon Trout Hatchery Project Report. 1961 and 1962.

82) 1963: Regulation of spawning period by light period

(memeographed). tC{6 I

83) Suisan Cho (The Fisheries Agency): Summary of 8th Meeting of

Salmon Trout Hatchery Div.

84) Tashiro, Fumio : private correspondence.

85)el Telkova, L. P. 1954: Experiment on stimulation of ovu-

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86) Terao, Shin and Tomozo Tanaka 1928: Effects of gregarious

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87) Tochigi-Ken Suisan Shikenjo Kuroiso-Bunjo (Kuroiso sub-sta-. tion, Tochigi-Ken Fisheries Experimental Station) 1963: Experi-

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88) »lb. Turner, C. L. 1919: The seasonal cycle in the spermary

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91) Yoshioka, Kan and Kiichiro Yamamoto : On the effects of light

8

-

i

, on the reproductive 'power 'of killifish, • lecture given at the

1961 - annual meeting of JàPan Fiàheries _ . _

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C # indictes those which could not be referenced directly)

'