CRASSOSTFEA VIRCTNICA MARICUItTURE IN MOLL1 FISHPOITD

OYSTER IXTTHCDUCTICiN ........................................ 7

............................. .......... BIOLOGY OF OYSTERS :. 11

.......... PHASE I: Effect of 'JarLcus Depths and S a l i n i t i e s 22 on the Growth Rate cf Oyster Spats

Statement of tht: l k c j e c t ......................... 23

Illethod of Conductil~g Study ....................... 25

Outl ine o f thc Study ............................. 30

.......................................... Results 34

Graphs ........................................... 39

Conclusion ....................................... 43

Data ............................................. 47

PlIASE 11: Effect of Various diet^ and Depths .............. 49 on the Condition Index Val-des of the E"krketab1c Gystcr

Statement of the Pro jec t ........................ 50

...................... Method of Conducting Study 52

............................ Outline of tho St-ddy 55

........................................ Results 60

Graphs .......................................... 65

Diet Cost ....................................... 70

Conclusion ...................................... 72

................. PHASE 111: Effect of Vario~r:; Dlc'i, on the 84 Growth Rate of Uyster :;patas

....................... Statement of tl:? Project 85

Method of Coilciucting S1;udy ..................... W

Outl-he of t h e Study ........................... 90

Resirlts ........................................ 93

Graphs ......................................... 97

Diet Cost ..................................... 102

..................................... Conclusion lo(+

Data ........................................... 106

PHASE IV: Spawning Techniques ............................. 108

.......................... Statement of the ':reject 109

...................... Method of Conducting 2t?rdg 111

............................ Outline of the ?i;lr;3;; 113

Results. ......................................... 115

Conclusion ...................................... 117

Discuss1

PROJECT CONCLIJS IO?!

...... A P P L I C A T I O K

LITEUTURE CITID . ACrnOIJLEDG~!~ lNTS . A P P F 2 D M .........

INTROD UC T I0 N

The oys te r produ.ction i n the Un-it,ed S t a t e s has decreased s t ead i l y s i nce

t h e l a t e 18001s. The f i t ~ c : of t he oys-tcr industry i s uncertain, but i f

present t rends contiliuc t o u t i l i z e improved ~ranagement and cultural.

techniques, then perhaps w i l l boostt.,r the oys te r production.

The Survey of t , t lc , O : ~ s t , c ~ Potcntpi?. l o f ~lawsj.ri=, s t a t e s that no

#---

s tud ies of t he g-ror~th r a t e of C. virrrinica h v e becn made i n Ilawaii and

assumes t h a t the growth of this species i n Hawaii does not g r e a t l y exceed

the maximum growth recor2ed f o r C. virprinica i n thc corltinental United

S t a t e s ,

A r epo r t t o the F i f t h Le,tisl.ature of the Sttat(:: of Hawaii Rudgct

Session of 1970 c i t e s that, oysters i n temperate regions of the world,

such as t he Continental United States and Japan do rlot grow f a s t e r than

oys te r s growing i n our w a r m wsters. The climate of Hawai i also providr :~

,- an environment conducive t o year around oys te r growth without i n t e r rup t i on

by cold winter teinperaturcs. Thus, oys te r s here m y grow t o marketable

s i z e of 3 inches i n 12 Lo15 months, whereas it tnltcls from 3 t o 4 years

f o r the same species of oysters t o attain similar s i z e on the eas te rn

seaboard of the United S ta tes .

Crassos t r ca v.irqin.ica M~si c u l t ~ ~ c tri MoZii Fishpond.

The a r t and sc i ence o r c u ' t i v a t i n g organisms ir, a s a l t w a t e r ? ~ c d i ~ ~ . n

has had d i f f e r e n t rimes down tbrongh the years, bu t i.n r c c c n t yea r s it

has come t o be c a l l e d mari.cultin-e. I . fa r icu l ture i s t h e c o n t r o l l e d and

semi-cont ro l led environment of f i s h and o t h e r organi.sms. I t i s a l s o

r e l a t e d t o pond c o ~ ~ s t r u c t i o n , breeding, c u l t i v a t i o n o f algae, laws and

l e g i s l . a t i o n s , and t h e s a l c o f organisms and hyproducts . - The o b j e c t i v c ; ~ o f t h i s p r o j e c t i s t o detormine t h e p o t e n t i a l

o f a n o y s t e r mariz:~l turr? i n I.4olii Fishpond, Kaneohe, Oahu. This s t u d y

t a k e s i n t o cons ide ra t ion s u r v i v a l , growth, spawning, and economy.

To reach t h e s e object . ives a 2 y e a r - 4 pilase oys1;er s tudy was

conducted i n 14olii F'isnpozd . Phase I - Effec t o f Gclri.oils Depths and S a l i n i t i e s on +.he Growth

Hate of' Oystcr :;pats

Phase I1 - E f f e c t of V a r i o u s Diets and Depths on t h e Condit ion Indcx valucs o f t h e LIarketable 3 y s t e r s

Phase III_ - E,i'fect of 'Jarious D i e t s on tht; Growth IL-itc o r Oystcr Spa t s

Phase I V - Spawning Techni-ques

BACKGROUND

The o y s t e r p r o d u c t i ~ n i n the United S t a t e s has decreased s t e a d i l y s ince

the l a t c 18C\OTs. Thc o f t he oyster industry i s uncer ta in , end i f

present tl-ends c ~ n t i ~ u e , increasing dependence on improved mnagene~l t and

cu l tu re techniques v i l l becone neccessary t o booster oyster production.

P r io r t o the present survey, various species resu l ted i n i n i t i a l

encouraging survival b u t eventual l o s s of' s tocks. Several p ~ ~ b l i c a t i o n s

hgve discussed the e f f ec t s t o ~ c c l i f i ~ t e both the American oyster , C. - vi rg in ica a d the s o f t ;he l l s l a~n , carenaria.

Ostcrgaard (1963) discussed t he introduction o f edible species of

s h e l l f i s h , and 2dmondson and Wison ( 1 9 5 ~ ) ~ i n a paper on t he s h e l l f i s h

resources of Hawaii, discussed t he h ~ ~ o r t a t i o r ~ of oysters a s well as the

presence of l o c a l spcies such as Ostrea sandwichensis, t h i s i s too in-

s i gn i f i c an t f o r human food. Final ly , Brock (1952 and 1960) recorded

f i v e species u f oysters which were introduced aud these a r e Crassostrea

v i r ~ ? i n i c a , the eas tern oyster ; Ostsea lWidn, t he O1)mpia oyster ;

.- Crassost,rea flipas, t h e Japanese o r Pac i f ic oyster ; Crassostrea commercialis,

the Austra l ian oys te r ; Crassostrea w s a , t he co ra l rock oys te r .

OYSTER INTRODUCTION

There i s some conf l inc t i n the statements of Minoadson and 'tiilson

(19.40) and Brock (1960) as t o the plantings which resu l ted i n e s t a b l i s h c n t

of t h i s species on 0,ahu. 'Re f i r s t importations, in 1871 and 1873, apparently

were unsuccessf'ul. Brock says t h a t p lant ings i n P e w 1 Hurbor by a p r i v a t e

individual i n 1893 and 1895 werr. both successfirl, while Edrnor~dson and

Wilson i np ly tha t the f i r s t successful t r a ~ s p l a n t s were by the i n i t i a l

1

T e r r i t o r i a l Division of Fish and Gane irr~ports i n 1921. Tho l a t t e r authors

s t a t e d t he r e was evidence that spawning and s e t t l i n g of t h i s spccins had

occured i n Pear l Harbor, k t t,hen s t a t ed fu r ther t ha t , :it t he time o f t h e i r

wri t ing (1940), t he eastern oyster had not become a l o c a l commercial

product .

Ostrea l u r i d a

There was, accordicg t o ex i s t ing records, only one a t t e p t t o e s t ab l i sh

- t h e Olympia oyster (ca l l ed California oys t c r by Brock) i n Hawaii, tha t

being an importation of some 3,000 speciments t o l h a n a , O~diu from San

Francisco in 1893 by John P. Colburn, who successfully (according t,o

Brock) es tabl ished C. v i r ~ i n i c a a t t h c sane timt. No records e x i s t of

of t h e f a t e o f the Ostrea l u r i 2a from this shipment, but it i s presumt-d

tha t they e i t h e r f a i l e d t o survjve o r t o reproduce. Sincc the Olynpia

oyster i s a cold water species, t he lat.t,er case is most l i ke ly .

The f i rs t recorded i q o r t n t i o n of the .Japanese o r P a c j f i c o y s t e r 122s

in 1926, w i t h a small p l a n t i n g made i n K a l i h i and Kaneohe on O a h u . Addi-

t i o n a l p l a n t i n g s of small numbers of t h i s s p e c i e s tc;ok p l a c e i n Pearl

Harbor and a t Mokapu on Oahu i n 193d, then, i n 1939, a large shipment o f

J apn~ iese seed o y s t e r s were p laced i n two a r e a s , Coconut I s l a n d and Mokapu,

on Oahu. l'he actual s i z e of t h i s p l a n t i n g was, accord ing t o Fhoncison and

Wilson ( 1 9 4 0 ) ~ "nore than one Id i l l i on seeds t t , wh i l e Brock (1960) s t a t r d t h a t

- 2,150,000 seeds were p l an ted . F&.ondson anti Ki l son n o t 4 t h a t , i n foim

months from t h a t pl p a t i n e un ti1 t h e i r paper was v r i t t e n , excep t iona l

growth had occured and they advanced the hope t h a t t h e s p e c i e s would

become permanently e s t a b l j s h e d . 3rock (1960) l i s t e d C. ~ i m s a s an

in t roduced s p e c i e s which probably d i d no t su rv ive . As will. be pointed

o u t i n a l a t e r s e c t i o n , lar!:e n m b e r s o f t h i s s p e c i e s a r e p resen t i n

Kaneohe Ray a t t h e p r e s e n t time, b u t appa ren t ly Ihe s p e c i c s f a i l e d t o

gain a foo tho ld i n Pearl Elarbor d e s p i t e the several a . t , t e q t s menti0nc.d a b ~ v e

- and a t l e a s t one impor ta t ion of seed I ,ys te rs by t h e ! J L ~ ~ S U Y ~ ~ T I K L EaSy about

three y e a r s ago, ! 1959) .

Brock (1960) l i s t e d two i np8 ) r t a t i sns o f this Austra15nn s p e c i c s , a

v e r y small sh ipmer t o f three b;~shcls i n 1729 and r. so~.lewhnt l a r g e r shipment

of 24 bushe l s in 1929. Desoi >c t h e small s i z e nf bath impor ta t ions , t h e y

were f'urther d iv idcd i n t o even s m a l l e r l o t s and p l en tcd on vt t r ious l o c u t i o n s

on Oahu, i nc lud ing Mest Loch o f P e a r l Hzrbor, Sand I s l a n d , and vnr tous

a r e a s i n Kaneohe Ray. l3dmandson 2nd Wilson, and Frock r epor t ed t h s t a l l

s t o c k died within sl;r months o f plant-ing.

A shipment, ccnsis t ing of cne '??-pound. nzck cf roc;.: q'stcrs:'from

Australia was brought t o Cocnn~lt 1slanc-l i n Kaneche Ray in 1356 and placed I

i n enclosed ponds. These oyster survived we l l , some a t :.east tmt?.l 1959,

but apparently no reproduction occurcd and e-xmin:~l;:i.cn o f ttie porids during

the present survey indicated the o r i g i n a l populntTon had died, au t .

BIOLOGY OF OYSTERS

The oys te r i s c, small sen a n i i ~ . a l wtth a z ~ f t , flcsl-<J bddg cnclosed

i n a s h e l l . It i s man's most vali~al,le scafcod. rhc oystei. l i v e s in many

p a r t s of t h e world, mostly in qu ie t , challot^ inlct ts .

The o y s t e r ' s r h e l l formc a s h e l t e r i n whjch ;t i i v o s . Tho she23 i s

divided i n t o two hnlves, c.al1c.d valves. Thesc artA fcstcncd togethcr ~t one

end by a hinge. A s t rong muscle, cnlled an adductor n ~ ~ s c i e , a t taches

t h e o y s t c r t s s o f t body t o thc s h c l l . Ey relaxing the musc:lc, t h e c y: tc3-

can open t he vblves about half ' r.n incli and by c o n t r ~ c t ~ i n g the muscle t hc

valves can be closed ES it des i res . Thc: l e f t vnlvc. i s lor ; ;c r , t,hic:l:er,

and more hollowed out thnn the othcr . 'F'ne oyster resL:; i n t be l e f t vclve .

The oys te r nttachcs its I c f t valve to n rock o r soml. o ther object on

t h e sca bottom, and s tays there t he r c s t o f i t s l i f e . C~mctimes sc:.rernl

oysters a t t a c h thanselves t,o each other nrrund the smc: r d c k . If t h e r e

a r e too many oysters i n the group, o r Lcd, thc olit::: on the bottorn may be

forced down i n t o the m d and d i p .

C- Every oyster s l lc l l is !ined. with 2- f1)lci of t i s s u e cal led a mantle,

which secre tes the l ayers of lir,~;r substance t h a t r r ~ ~ k c un t h e s h e l l . Thc

laycrs overlap l i k e the s h i n p l e ~ on n roof . SL)metimcs n p a r a s i t e o r scmc

other ob jec t becomes lodged :)n t hc ins ide of the s h e l l , nnd may i r r a t c t h c

oys t e r ' s s o f t b ~ d y . The oyster scc re tes limes ovcr the object, and j n

time a p e a r l i s formed. The ~ y s t c r s t h a t ,arc f:meri pearl mzkcrr a r c

not the cd ib le kind of thr; dor th Tempcrt=te Z,)nl;. I car1 ~ ) ; ~ s t e r s l i v c i n the

t rop ics and produce t h e mother nf p e a l w d the p c i r l ~ of commerce. ll.clit~le

oyster produce worthless pc n r l s . The oys te r has a mouth, c-)nsi;tiny: o f a funnel-sh: ;wi opening :.t thc

narroldest p a r t o f thc body. Tiny, f i nge r l i ke praject ions i n the mouth t a k e

from the water the many p lan t s end ani~nals which the c~ys tc r c a t s . The

oyster a l so has r, good sizoc! stomach connected w i t h -the mouth by a s h o r t

g u l l e t , a d iges t ive g lmc i , an intestine, a d2r?r-green l i v e r , rc;c,ruuduc Live

organs, two pairs of g i l l s f o r breathing, a two ?a i r s or ch~~ilbercd hea r t ,

and a ra ther simple and clernentzry nsrvotrs system.

Many sc ient is ts claim tha t the oyster may l i v e as lorig as twenty years

i f it is not disturbed.

Oyster eggs are yel.lowish i n color, ~ n d s o t i r u t hu t n mass of them

looks l i k e th ick cream. An average s i zed oys te r of the oastern American

coast may produce as many a s 500,000,000 eggs i n a season liany nf the b

young of t h e oyster are eaten by other animals, znd the -1y:;ters must, lay

many eggs i n order f o r any t o survive . The parent throws out t he s g ~ s i n

a s o r t of m i l k y spray. About t e n hours a f t e r the eggs ru-e fertilized the

baby oyster i s hatched an able t o swim. A t t h i s s tage It, i s cal led n

ve l iger l a rvae . It i s then about t he s i z e o f a needle point.. It s w i m s by

meam of h a i r l i k e growths c a l l e ~ t c i l i a . A nadimentary silell begins t o

form within the next twenty-four ho~ l r s .

During t he f i r s t two wc-eks of m 3 y s t e r f s l i f c , i t swims about looking

.- f o r a place t o s e t t l e . Young oysters o r e i n g r ea t dancer from f i s h which

may eat severa l thousand o f the young larvae, Idhen it f i n d s a placc t h a t

i s s a t i s f ac to ry , it at taches i t s e l f t o t h a t spot and stays t he r e f o r t h e

r e s t of i t s l i f e .

Soon t h e pr imit ive s h e l l 5.s formed, and t he larva dcvr.1-ops i n to s n

adu l t oys te r . I n a month t he young oyster i s about the s i z e o f a pea.

A t the end of a y e o r it is ns large as a s ivc r q i ~ n r t c r . LfLer t h a t it

grows about an inch 3. year u n t i l i t reaches fill s i z e aL (,he end of threc

o r four years

During t h i s t ine it may be at tacked by s t a r f i s h , snnil-s , rind o ther

hungry enemies. One of these, t h e boring s n a i l , pierces .the :;hell. v i t h

i t s rasping tongue, and drnt.1:: out the s o f t oys te r . One s c i e n t i s t estimated

The f i shpond which t h e s tudy was conducted is owned and opera ted by

my f a t h e r . The Moli3 Fishpond i s about 130 acres , ( f i v e ) . About Q o f

the pond, which I s d iv jded by a s t o n e wa l l , ha s a depth cf 1-4 f e e t The

oppos i t e end i s most ly shnllow. There a r e msny fcrrns around t h e pond.

When it r a i n s t h e wetcr from the l a n d runs i n t o t h e pond and as s r e s u l t

t h e water i n the? yond i s n o t alwzys salty. The ocean water and pond

water mix by means of waterga tes and seepage through thc s t o n e wa l l . k t

one end o f t h e pond 5s marsh area. Trees l inc : % of the pond's pe r ime te r .

The f l o o r of t h e pond is made up most ly of mud end sand. The water samples

t aken seem t o i n d i c a t e a vcry f e r t i l e cnvironment.

Other orgmisms i n the pnnd i n c l u d e flski, crr;t)s, shr-Imp, bugs, s n a i l s ,

worms, algae, and sponge.

MOLI I F I S H P O N D - -

Studies of s. ari:Sni.~g s p a t s i n Iiawaii has never t een done . Perhnps

by adequately con t ro l l ing c e r t s i n var iab les , t he e f f e c t o f d i f f e r e n t depths

and d i f f e r en t degrees of s a l i n i t y on the develcpmc-nt of thc C. yirginic'a spats,

one can determine t he su i tab . i l i ty o f e s t a b l i s h i n g m maricult,lcre i n d u s t r y i n

Hawaii.

Objectives :

This s tudy seeks t o answer t h e questions:

- 1. Is there a differc:nce i l l t.he growth rat,c: of C. v i r ~ 5 n i c a spa t s , when

subjected t o d i f f e r ~ n t depths and d i f f e r e n t degrecr, of salini1,y i n a seini - control led na tura l ~ n v i r o r m e n t ~ ?

2. What are the optimum r n n d i t i o n s i n Nolii Fishpond for the best growth

of G. virpinicn?

METHOD OF COhiUCTING STbiDY

C. vir,qinica spa t s werc subjected t o th ree d i f f e r en t depths and two

d i f f e r en t s a l i n i t y cona i t io~ ls . The choice of depth and s a l i n i t y s tud ies

were determined by the physical d i f ference within ?!olCi Fishpond. Five

experimental t r ays were prepzred with 200 spa t s s tored i n each.

Three d i f f e r en t depths vas used i n my study. The f i r s t was placed a t

one foot t h e surface of the water, t he second a t f i v e f e e t below, and

t h e t h i rd depth was t e n f e e t below t h e surface of t h e water. Tray 1 was

"-

labeled one foo t , Tray 2 was label-ed fi-re f e e t , and Tray 3 was labeled

t e n fee t .

The d i f f e r e n t dngrees of salinity within the ponds wcrc produced by

rainfall and t h e exchange of xa t e r bctween the pond and t he ocean. Tray L'+

was located i n an a r ea of relatively high s a l i n i t y and Tray 5 i n an area of

r e l a t i v e l y low s a l i n i t y .

To c o l l e c t spats , I hamered apart the i l ldividual spa t s from the

co l l ec to r p l a t e s . I then placed 200 spa t s i n each t r a y and covered the

*- t r a y with a wire screen.

I col lected data evcry two weeks. I measured a t random 100 spa t s . I

used a verne i r ca l iper and measured t hc s h e l l length of spats i n mill imeters.

The method used t o measure t he oys tc r s i s t o placc t he ca l i pe r s a t t he

wnbo and extend it t o t he outer edge of t he s h e l l . A t each t r a y locat ion,

I took the temperature and s a l i n i t y of the water. Thc t c r n p c r a t , ~ ~ ~ e was

taken by t h e use of a Celsius thernonleter and the s a l i n i t y by uo ,e of a

hydrometer and SJinker t i t r a t i o n technique. The weather coriditions wcrc

noted week2y. The conditions of spa t s and t r ays were alsc recorded. Any

o ther living organism located within o r on the tray vas c,uzlclined and i t s

presence recorded.

I * . 1- (-, ;.

J..

C. For

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I7 . . 1-<!:,;!r,:t:-.f , \ : I 2 F ::.:: i?,: !-,,! ! : : : , x ~ j - : r . ~ : ) ' ., ! .: : <,.; 5 .

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(1. i ' ( ! l - , < ..:;.:<.,.: llc:.i 1 ,;

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it. ? ~ a ~ x . c . r

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{'T;S:C~. l t ;y?-- . . r

; 7 [.I/,-?

RESULTS

A t the end of the eighteen week experimental period differences were

found among the spa ts t h a t were subjected t o d i f f e r en t depths .

Trax D e ~ t h of Tray - Grawth increase i n mm_ Dezths O r i ~ l n d s , w l e

1 1 foot 39 1 200

2 5 f e e t

3 10 f e e t n"

Differences were also found among the spats which were subjected t o

high and low s a l i n i t i e s .

2 E X b e of Sa l in i ty Growth increase i n Q Deaths ~ i g i n a l s m l e

4 high (28-33%4 29 nun 0 200

5 low (21 -26x0) 49 mu 1 200

TABLE 1: AVERAGE GRO\!TfI O F OYSTER SPATS I N V A R I O U S D E P T H TRAYS

T r a y D e p t h

1 1 f o o t

2 5 f e e t

3 10 f e e t

.. - D a t e --

11/21/70 31 mm 31 nun 31 mm

12/6/70 37 nun 37 mm 3 7 m

12/27/70 43 mn 41 nun 40 mm

TABLE 2: EFFECT OF SAT,INITY O N AVERAGE GROIJTJI OF OYSTER SPATS

T r a y 4 5 S a l i n i t y High (28.0-33.0 Z,) Low (21.0-26.0%')

Date

3 1 mm

36 mnl

38 mu

40 mrn

41. mm

47 mm

5 1 mm

56 mm

31 rnm

40 mm

47 mrn

5 2 mrn

57 nm

60 mm

62 mm

70 mm

TABLE 3: TEMPEPdITURE AX9 SALINITY OF WATER AT THE REARTKG TRAYS

Date Tray 1 Tray 2 Tray 3 Tray 4

11/12/70 Temperature C\= Salinity %;

23.6OC 29. OX,,

12/6/70 Temperature 'C Salinity %>

12/27/70 Temperature 'C Salinity %:

20. oOc 2 8 . OX.,

*A

1/10/71 Temperature 'C Salinity %,

2 4 . O°C 23. OX..

1/24/71 Temperature 'C Salinity %,

23.5'~ 2 9 . OX,

2/7/71 Temperature OC Salinity %,

2/21/71 Temperature 'C Salinity %:

3/14/71 Temperature 'C Salinity %,

3/21/71 Temperature OC Salinity % ,

. j -.

I

I

-. 0

I

1 -

. ' --- * . . "+*

6--

I i

- - - . I

I I I 1 L

' % ' , 0 v,, 77 a/a, q', 32,

I

I r910 - ! ic1-1 I I

S a m p l i n ~ Dates L -

a -- - . - ". -1 . . -

CONCLUSION

From t h e r e s u l t s of the da ta taken from my experiment, it

i s evident t h a t the va r i a t i on of depth and s a l i n i t y has an e f fec t

on the growth of t he C. v b ~ i n i c a spat.

The bes t depth f o r growing C. v i r a ln i ca was represented from

Tray 1, which was located one foo t below the surface of t he water;

T h y 2 had t he second bes t growth which was located 5 feet below

t h e surface of t h e water; and f i n a l l y , Tray 3 which was located

10 f e e t below t h e surface of t h e water.

The b e s t s a l i n i t y from growing s. v j r a in i ca was represented

by Tray 5, which was located i n an a rea of low s a l i n i t y .

By emminiation of t he r e s u l t s t he following general izat ion

can be s t a t ed : The bes t condit ion f o r the growth of C. v i r ~ i n i c a

i s a t t h e surface of t he water with low s a l i n i t i e s .

In answer t o questions which were s t a t ed i n t h e Statement of

t h e Problem:

1. Is there a di f ference in t h e growth r a t e of C. v i r a in i ca s p a t s when subjected t o d i f f e r e n t depth and d i f f e r e n t degrees of s a l i n i t y i n a semi-controlled na tu r a l enviro* ment?

Yes, the re i s a dif ference i n growth r a t e when C. v i r a ln l ca spats a r e subjected t o d i f f e r e n t depths and differenmt degrees of s a l i n i t y .

2. What a r e t he optimum condit ions i n Molii Fishpond f o r the b e s t growth of C. vi rg in ica?

There is evidence that growth r a t e increases when C. virainicn spa t s a r e cultured a t t he surface of t he water in low s a l i ~ d t i e s .

D LS CUSS I O N

From m y experiment the r e s u l t s show an increase i n t h e g r ~ w t h

r a t e of C. v i r ~ i n f c a spa t s when subjected t o low s a l i n i t y and

shallow \rater. This i s indicated by t h e r e s u l t s of Tray 1 and Tray 5

which showed the be s t growth among the tsays . My r e s u l t s do not show

the limits of shallow water l eve l s nor of the lowest s a l i n i t y l eve l s

which t h e oyster can withstand and survlve. Rut my r e s u l t s i nd i ca t e

a favorable growth increase when t h e spa t s a r e subjected t o low

s a l i n i t i e s and shallow water. Dcreases i n depth and s a l i n i t y

resu l ted i n l e s s favorable growth,

I r e a l i z e t h a t s a l i n i t y and depth may not be t he only f ac to r s

that a r e contr ibut ing t o t h e growth of the oyster spats . Perhaps

t h e loca t ion of t h e t r ays where t h e s a l i n i t y and depth l eve l s a r e

low may influence the growth r a t e of the oysters because these t rays

a r e located near t he f r i nge of the pond where there a r e many HRQ

b e e s . Birds o r a n i m l s which l i v e in these t r e e s m y contr ibute and

influence t he food supply of t he oys te r s via t h e i r waste products

which f a l l i n t o t h e water. There a r e a l s o m n y a g r i c u l t u r a l farms

located around t h e pond. These farms use f e r t i l i z e r s which m y run

o f f during t he r a i n i n t o t he pond and a s a r e s u l t add t o t he food

supply i n d i r e c t l y because t he f e r t i l i z e r would promote t he gra-dth of

microscopic organisms which the oys te r feed on. Surface waters a r e

more productive due t o photosynthesis and t he abundance of a lgae

supply. There Is probably more water movenent a t t he surface due

t o wind blowing across t h e pond than a t deeper l eve l s . The water

movement i s needed t o ca r ry food mate r ia l t o t he oysters. Conversely,

growth my be M e r e d by th ick sediment growths on spats, which a r e

seen espec ia l ly on t he spa t s grown a t deeper depths.

S T A T D ~ J T OF THE PROBIB4

Since it was found from t h e r e s u l t s of Phase I, t h a t C. v i r g i n i c e s p a t s

will su rv ive and t h r i v e i n Hawaiian waters , through t h e c o n t r o l o f c e r t a i n

foods and d i f f e r e n t depths on t h e marketable s i z e o y s t e r , one can de termine

t h e grade o r value of $he o y s t e r meat produced. This va lue is r e f e r e d t o

as the c o n d i t i o n index.

Ob jec t ives :

This s t u d y seeks t o answer t h e ques t ions :

1. If t h e r e i s a d i f f e r e n c e i n t h e Condit ion Index va lue o f C.

v l r a i n i c a , when sub jec t ed t o d i f f e r e n t foods and d i f f e r e n t dep ths i n a

semi-control led n a t u r a l environment?

2 ' h a t a r e t h e opti~mun cond i t i ons f o r achiev ing t h e Condit ion

Index va lues o f C. v i r g i n i c a ?

STUDY

The marketable s i z e C . v i ~ y s g i ~ of Phase I were subjected t o th ree

d i f f e r e n t types of foods th ree different depths. The choice of foods

were determined by t he n u t r i t i o n a l needs of s h e l l f i s h , atrsilability, and

economy. The choice of depths wcro determined by the physical d i f ferences

within Molii Fishpond

Three d i f f e r e n t types of foods were used A l l t r ays were subjected

t o a depth of one foo t and i n low s a l i n i t y weas a s recommrtnded by Phasa..I.

Tray 1 - oysters were fed 10 ounces o f processed food once a day.

t he tray was designed t o maximize s i m u l n t i ~ n of oysters i n t h e i r na tu r a l

environ.. The food was a c o r n f l a w mixture consis t ing of:

Minimum cmde pro te in Mlnirmun crude f a t Min i rm crude f i b e r

I Tray 2 - oysters were subjected t o chemically f e r t i l i z e d water. a

pound of f e r t i l i z e r was added t o t h e water each week. The t r a y and

enclosing frame were designed t o maximize simulation of oysters i n a

m

semi-controlled environment. An aera t ion system was added t o compensate f o r

l o s t of na tu r a l wave ac t ion and dissolved oxygen. The chemical f e r t i l i z e r

consisted o f :

10% Nitrogen 10% Phosphoric Acid

5% Potash

Tray 3 - oysters were subjected t o t he ambient conditions of t he pond.

It served a s t he control f o r t h i s experiment. The n a t u r d food consisted of :

Plankton, diatoms, algae, l a rvae o f crustaceans, e t c . .

Three d i f f e r en t depths were used i n m y p ro j ec t The f h s t , Tray 3 , one

f o o t below t h e surface of the water - t h i s t r a y a l s o served as the can t ro l fo r

the food study Tray 4, f i ve f e e t belori t h e surface of *,the water. Tray 5,

t en fee t below the surface of the water.

Data was col lected every two weeks For each tlray, 20 oysters were col-

l e c t ed a t random. To determine the condit ion index ~ . ~ h i c h gives an ind ica t ion

o f t he q u a l i t y of the oys te r nea t the fol loving re la t ionsh ip was used:

Cavity V o l ~ ~ i e : llhole oys te r i n M i l l i l i t e r s (-)-I- s h e l l u/o neat i n P l i l l i l i t e r s

C w ~ i t y volume i n l r i i l l i l i t e r s

Dried meat wei&ht: Dried meat w/foil i n grams (- o oil ~reicht i n rrrrun:;

Dried m a t vt. i n g r c m

Condition Index: ( ~ r i e d oys te r meat wt./cavity volume) X 100 C . I . = value i n grn /xi!..

A t each t r a y loca t ion the temperature, s a l i n i t y , dissolved ovgen , and - . .

c o l i f o m of t h e water were taken, The weather condit ions were no tedxnd the

condit ion of the oysters and t r ays were e l so recoroded. Any o ther l i v i n g

organisms located within o r on t he t r a y were examined and its presence

recorded.

OUTLINE OF THE STUDY

I. Materials and Equipment Used

A. For Preparation of 3 Depth Experimental Trays

4. One f o o t depth t r a y

a. Lumber

b. -$- sq. inch wire mesh

c . Horseshoe mils

d. 4 i r o n pipes

e . Hammer

2. 5 and 10 f e e t depth t r ays

a. $ sq. inch wire mesh

b. Wire t ies

c. Nylon ropes

d. 2 i n f l a t cd rubber tubes

e. 25 pound weight

B. For Paraparation of Experimental Food Trays

1. Processed Food Tray

a. Lumber

b. sq. inch wire mesh

c. Horseshoe n a i l s

d. 4 i r o n pipes

e. Hammer

2. Chemical F e r t i l i z e r Tray and Enclosure

a. Lumber

b. sq inch wire mesh

c. Horseshoe n a i l s

d. Hammer

e. Nonstop ( t a rpaper )

f . 4 i r on pipes

g. Shovels

3. Natural Food Trny

a. Lumber

b. -5 sq. inch wire mesh

c . Horseshoe n a i l s

d. 4 i r o n pipes

e, Hanner

C. Foods

1. Processed food

2. Chemical f e r t i l i z ' e r

3 . Natural food

D. For Oollection of Spats

1. Spat co l l ec to r

2. Oyster h m e r

3. Gloves

E. For Collection ~f Data

1. Gram sca l e / Drq\ng O v m

2. Oyster lrnife

3. Glwes

4. Aluminum Fo i l

5. Milipore K i t

6. Thermometer i n degrees C

7. Hydrometer and s a l i n i t y d e t e r d n a t i o n (chemical)

8: Dissolved oxygen (Winker method)

9. Data book

11. Procedure

A. Construction of 3 Experimental Trays

1. One foo t depth t rays

a. Construct wooden frame ( rectangle)

b. Nail wire screen t o a c t as bottom of trriy

c. Constnzct oover of wire

d. On loca t ion hamTner in 4 i ron pipes f n ground

e. Udng wire hooks, hang t r a y i n pipes

2. 5 and 10 f e e t depth t r a y

a . Construct c i r c u l a r frame of wire

b. T i e n c l r c u l a r wire bottom t o frame a s t o a c t a s bottom

c . T i e nylon rope t o frame t o suspend t he t r a y i n t h e

water a t detepmined depth

d. To rope at tached t he In f l a t ed rubber tube

e. Attach another rope t o each t r a y and t i e t o weight

which serves as an anchor

B. Construction of 3 Experimental Food Trays

I . Processed food t r a y

a. Construct wooden frame (rectangle)

b. Nail wire screen t o frame t o a c t a s bottom of t r a y

c. Construct cover of wire

d . On loca t ion hamcr in 4 i ron pipes is ground

e . Ushg wire hooks, hang t r a y i n pipes

C. Col lect ion of Spats

1. Hammer s p a t co l l ec to r p l a t e s t o separate spa t s from each o t h e r

2. Measure and place 200 spa t s in each t r a y

D. Collection of Data -O& ~ ~ , b - k . y r u )

I. Measure t h e length of 100 spa t s every two weeks

2. Determine t he length i n mill imeters

3 . E x d n e and record i n da t a book

4. Record condit ions

5. Record temperature and s a l i n i t y

E. Collection of Data

1. Collect 10 spa& every two weeks

2. Determine C . I . value by use of formula

3. Examine and record i n data book

4 Record condit ions

5. Record temperature and s a l i n i t y

RESULTS

At t he end of the thirteen week experimental. period differences were

found among t he oysters tMt were subjected t o d i f f e r e n t foods.

F i r s t Last Original W A X me of Food C . I . Value C . I . Vdue '2.1, Increase Death3 S m l e

1 Processed 3.79 14.26 10.47 0 200

2 F e r t i l i z e r 3. '79 14.23 lo.& 1 200

3 Natural 3.79 3.28 -0.51 0 200

w=. Differences were also found among the oysters which were subjected t o

different depths.

F i r s t Last Orf gi na l D e ~ t h of Tray: C . I . Vdue C . I . Value C.I. Increase Deaths S w l e

3 1 f o o t 3.79 3.28 -0.51 0 200

4 5 f e e t 3 79 2.41 -1 .38 0 200

5 10 f e e t 3.79 2.17 -1.62 0 200

TABLE I : - mmCT OF V.4RI0iiS FOODS-ON COI?DITXOM IlDEX VATJJJ33 OF 154RICETAELE FYSTER

Tray 1 2 3

Type of Food Processed Fertilizer Naturd. p-..--.

Date :

9/5/71 3.79

9/19/71 9.89

1 0/3/71 11.56 rP*

10/17/71 12.43

I 0/31/71 13.61

1 I /I 4/71 13.82

1 I /28/71 14.26

TABLE 2: P F E C T OF VARIOTJTS DEFTRS ON RE COXDITION IETDFX VALUES OF ~PL-r(ETIBLE OYSTER

Tray

Depth

3

1 foot

4

5 feet

5

10 feet

Date : - 9/5/71 3.79

9/19/71 3.86

1 0/3/7 1 3.63 -Y-

10/17/71 3-93

10/31 /?I 3-41

I I /14/71 3.26

1 1 /28/71 3.28

TAB13 3: Tk:!~2~k,tlATURE, SAI,TNTTY,DTc~I~~T>I OnGFFr_;5 ANI) COLIFORM COUNT OF TH", WATER -

Date Tray 1 Tray 2 Tray 3 Tray /+ Tray 5

9/5/71 TemneratureL C 30.0'' C 30.0 'C 29.5 C 28.3"C 27.GC Salinlty % 28.2% 26!. 4% 28.7% . 29.6%. 29.4$.- Dissolved 0, 15.69 15.69 15.69 15.63 15.64 Coliform - - - - - 9/19/71 Temperatureb C - Salinity %: Dissolved 0, Coliform

1 0/3/7 1 Temperature "C Salinity %.- Dissolved 0, Coliform

10/17/71 Temperature C Salinity % Dissolved 0- Coliform

- 10/31/71 Temperature ' C

. Salinity %&

Dissolved 0 ,. Coliform

1 1 /I 4/71 Temperature.- C Salinity % Dissolved 0, Coliform

1 1 /28/71 TemperatureLC Salinity %- Dissolved 0- Coliform

Tr ., - .:-- 7 . k ..,--. , , , T . , , Y - - 7 c.1, ,~IJ><~.: i f , IJ.:,, . L L . l , L.-' s, -,':~,;L!:I:;i cy373j13 - ,.-.. - - . ._ .-;:{<;,;:< I:.: ' , A e A A l J ;,;li',b!-; , ;,&I*-- .,L,. - '-- PC,, - L . , -. , . - * - .;.

~ ~ L ~ ~ , ~ 17: T;,"i:ji;ifrI<,i! liI, 5 s.),-' !- .,-,: .. ,-

- . v 4 . i xi::-; .LA1. .~-L!L.II 7 T . ? - " --. - - . , 4 . .

. , J ! . , V !i -:L,

,'

43 -

I

35

33

-

- 2 5

n

0 *,r,

- w 23

h +' 4 '2 4 14 n! rn

14

I 0

5

, 0

- t

I

. .

t

+

- t I i?cr 1 )

, ) (7" . , - I ) L 7. .-y ', )

- -

I

.

I

, 1

- I 1

/ Kc, '173 I%1 I G; 2 I ''/a4 '% s

I Q T \ I 't-l r 3 ~ ! ? l ~ > l l 3 1 TI!> t3 h

- - - - ' I

q 1'7 .~., . ~-. -- l s I ~ ~ P 5 ~ ~ . ! . ~ ~ i ~ V?i:iii~TI,:;: I;, ,<LLII ?Isi:pc;;y:, ,'. .-..I '-. .. 1 , r i i ~ . ~ ~ ~ ~ ~ + U;~;;I;

FOOD COST

A t the end of the thirteen week experimental period difference- a vere

found among the cost of feeding the oysters the various types of food.

Tray Type of Food Food cost per week Total cost

Processed

Fertilizer

Natural

CONCLUSION

From t h e r e s u l t s of t he da ta taken from my experiment;, it is evident

that the va r i a t i on of d i e t and of depth has an e f f e c t on the condit ion

index value of t he C. vsir~tini ca oys te r . Oyster meat with a Condition Index value of 10.00 is considered t o p

grade according t o t h e Department of Fish and Game. From ny experiment

t h e r e s u l t s show t h a t within a months time, I am ab le t o condit ion oys te r s

t o t h i s degree using e i t h e r processed food o r chemical f e r t i l i z e r . This i s

+=- indicated by Trays 1 and 2. After a t h r ee month period the 14.00 value

was reached by both t rays .

I n t h e case of t h e depths t h e b e s t C . I . value was reached by Tray 3

a t one foo t below the surface of t he water. Since t h e coliform l e v e l s were

of a negative nature, t h e oysters a r e assumed s a f e f o r human consumption.

The Department of Fish and Game has a l s o checked t h e coliform l e v e l s and

recieved similar r e s u l t s .

By examination of the r e s u l t s t h e following general izat ion can be

- s t a t e d : The bes t condition index values a r e reached when oys te r s a r e

subjected t o e i t h e r processed food o r chemical f e r t i l i z e r and in shallow

water.

I n answer t o nv questions which were s t a t e d i n t he Statement of t he

Problem :

1. If the re i s a di f ference i n t h e (3.1. value of C. vi rg in ica , when

subjected t o d i f f e r en t foods and d i f f e r e n t depths i n a semi-controlled

na tu r a l environment?

Yes, t h e r e i s a d i f fe rence in the C . I . value of C_. v i r p in i ca oys te r s

when subjected t o d i f f e r e n t foods and d i f f e r e n t depths.

2. What a r e the o p t i m condit ions fo r achie-dng t h e b e s t C.I. values

of G. yjxginica?

There i s evidence t h a t C . I . valucs increase when g. v ix-~ in ica oysters

are subjected t o e i t h e r processed foods o r chemical f e r t i l i z e r a t a

s h d l o w depth.

DISCUSSION

From my experiment t h e r e s u l t s show an increase i n the condit ion index

o f c. v i r ~ t i n i c a oysters when fed e i t h e r precessed food o r subjected t o

chemically f e r t i l i z e d water a t a one foo t depths. Th i s i s indicated by t h e

r e s u l t s of Tray I and Tray 2, which shocred t h e bes t C . I . value of 3 foods

t es ted . Tray 3 resu l ted i n t he be s t C . I . value of the 3 depths t e s t ed .

My r e s u l t s do not ind ica te t he l i rn i ts of shallow water l e v e l nor have a l l

poss ible types of foods been tes ted .

- For a p r a c t i c a l , e f f i c i e n t , and p ro f i t ab l e oyster mariculture industry

t he use of chemical f e r t i l i z e r in an area of low s a l i n i t y and i n sha l l ow water

will r e s u l t Fn the bes t condition index.

Since 2% was found from t h e r e s u l t s of Phases I and I T , t h a t c. v i rg in i ca

spa t s and oysters will survive and t h r i v e i n Molii Fishpond, through t he control

of c e r t a in foods a t a shallow depth, one can determine the e f f e c t food w i l l

have on the grouth r a t e of spa t s .

Objectives :

This study seeks t o answer t h e questions:

1 If the re is a di f ference i n t he growth r a t e of s. v i r ~ i n i c a spa t s ,

d(UL when subjected t o d i f f e r en t foods a t a shallow depth i n a semi-controlled

natural environraent?

2. lorhich food(s) r e s u l t s i n the be s t growth of C. v i r ~ i n i c a a t a

shallow dep th i n 1Jioli.i Fishpond?

METHODS OF COhJDUCTIf\rl; STUDY

C. virni- spats were subjected t o th ree d i f f e r e n t types of foods

and a t a depth of one foo t in 101.1 s d i n l t y areas a s recommanded by Phase I.

The same quanity and types of foods were used as i n Phase 11.

The C. & ~ i n i c n spa t s were subjected t o th ree d i f f e r e n t types of foods.

The choice of foods were d e t e d n e d by t he n u t i t i o n a l needs of s h e l l f i s h ,

a v a i l a b i l i t y , and economy.

Tray 1 - oysters were fed 30 ounces of processed food once a day. The

6.c

t r a y was designed t o maximize simulation of oysters i n t h e i r na tu r a l environ.

The food was a cornflour mixture consis t ing o f :

M i n i m crude pro te in Min i rm crude f a t Minimum crude f i b e r

Tray 2 - oysters were subjected t o chemically f e r t i l i z e d water. 2- pound

of f e r t i l i z e r was added t o t he water each week. The t r a y and enclosing freme

were designed t o m i m i z e sirmilation of oysters i n a semi-controlled environ-

ment. An aera t ion system was added t o compensate f o r l o s t of na tu r a l wave

ac t i on and dissolved oxygen. The chemical f e r t i l i z e r consisted o f : _I-

10% Nitrogen 10% Phosphoric Acid

5% Potash

Tray 3 - oysters were subjected t o the ambient conditions of the pond.

It served a s t h e control f o r t h i s experiment. The na tura l food consisted o f :

Plankton, diatoms, algae, l a rvae of crustaceans, e t c .

I col lected data every two weeks, f o r each t r a y I measured a t random

100 spats . I used a verne i r c a l i pe r and measured t h e s h e l l length of spa t s

i n mill imeters. The method used t o measure t h e oys te r s i s t o place the

ca l i pe r s a t t h e umbo and extend it t o the ou te r edge of t he s h e l l . A t each

t ray loca t ion I took t h e temperature and s a l i n i t y of t he water. The dissolved

oxygen content was a l so taken. The t e q e r a t u r e was taken by t h e use of a

Celsius thermometer while t he s a l i n i t y was tdren by the use of a hydrometer.

The weather condit ions were a l so noted f o r each wcek. The condit ion of spa t s

and trays were a l s o recorded. Any o ther l i v i n g organism located within o r

on the tray was examined and i t s pr5sence reccrded.

2. Oyster hammer

3. Gloves

D. Collection of Data

1 , Vernier c a l i pe r (mill imeters)

2. Formalin so l c t i on

3. Thermometer i n degrees C

4. Hydrometer t o determine s a l i n i t y

5 , Data book

,.I-

11. Procedure

A . Construction of 3 Experimental Trays

1. Processed food t ray , chemical f e r t i l i z e r , and na tu ra l

a. Construct wooden frame (rectangle)

b. Nail wire screen t o frame t o a c t as bottom of t r a y

c. Construct cover of wire

d. On loca t ion hammer i n 4 i ron pipes i n ground

e. Using wire hooks, hang t r a y i n pipes

B. Collection of Spats

1. H m e r spa t co l l ec to r p l a t e s t o separate spa t s from each o the r

2. Measure and place 200 spa t s i n each t r a y

C. Collection of Data

1. Measure t h e length of 100 s p t s every two weeks

2. Determine t h e l eng th i n millimeters

3 . Examine and record i n da t a book

4. Record conditions

5. Record temperature and s a l i n i t y

OUTLINE OF THE STUDY

Materials and Equipment Used

A . For Paraparation of Experimental Food Trays

1 Processed Food Tray

a. Lumber

b. sq. inch wire mesh

c. Horseshoe n a i l s

d. 4 i ron pipes

e . Hammer

2. Chemical F e r t i l i z e r Tray and Enclosure

a. Lumber

b. sq. inch wire mesh

c. Horseshoe n a i l s

d. Hammer

e. Nonstop ( tarpaper)

f . 4 i r on pipes

g. Shovels

3. Natural Food Tray

a. Lumber

b. sq. inch wire mesh

c. Horseshce n a i l s

d . 4 i r on pipes

e . Hammer

B. Foods

1. Processed food

2. Chemical f e r t i l i z e r

3. Natural food

C. For Collection of Spats

1. s p a t co l l ec to r

A t t h e end of the eleven week experimental period di f ferences were found

among the spats t h a t were subjected t o d i f f e r e n t foods.

Tray Type of Food Growth increase Deaths Original i n mm sample

1 Processed

a+"- 2 F e r t i l i z e r

3 Natural

TABLE 1: EFFZCT OF VARIOUS FOODS ON THE GROWTII RATE OF OYSTER SPATS

Tray 1 2 3

Food Processed Fertilizer Natural

Date :

TABU 2: TEXPEFtATURE, SALINITY, AXD DISSO1,VEI OXYGZM OF - THE WAmR

Date Tray 1 Tray 2 Tray 3

1 1 /28/7 1 Temperature" C Sa l in i ty %-*

Dissolved OL

1 2/12/71 Temperature "C Sa l in i ty %<,

Dissolved 0,

1 2/26/71 Temperature" C Sa l in i ty %; Dissolved 0,

1 /9/72 Temperature' C Sa l in i ty 5: Dissolved 0 ,

1 /23/72 Temperature'C Salinity % L

Dissolved 0. *-

2/6/72 Temperatureo C Sa l in i ty %.. Dissolved 0 ,

FOOD COST

A t the end of the eleven \!ttclc e:?crjnrntcl period d i f fe rences were

found eruong the cos t of feed.ing t he 02-sters t he various types of food.

Tray Type of Food Food cos t per week Total cos t

1 Processed $0.20

2 F e r t i l i z e r $0.02

Natural

CONCLUSION

From the r e su l t s of the data taken from ~y experiment, it i s evident

t h a t the var ia t ion of d i e t has an a f f ec t on growth r a t e o f C. v i r ~ i n i c a .

spats.

$he bes t d i e t f o r growing g. *$nic3 was represented by Trays 2, i n

which chemical f e r t i l i z e r was used, Tray 1 had the second best growth i n

which processed food was used, and f i n a l l y Trays 3, i n which the natural

food was used.

r.- By examination of the r e su l t s the following generalization can be

s tated: The best d i e t f o r the growth of C. vi ra in ica spats is chemically

f e r t i l i z e d water.

In answer t o my questions which were s tated i n the Statement of the

Problem:

I . If there i s a difference i n the growth r a t e of g. virginica spats ,

when subjected t o d i f fe rent foods a t a shallow depth i n a semi-controlled

natural environment?

- Yes, there i s a difference i n the Growth Rate o f 5. vi re in ica spats

. . when subjected t o d i f f e m t foods i n shallow water i n a semi-controlled

natural environment.

2. Which food(s) r e su l t s in the best growth of C_. vikninica a t a shallow

depth i n Molii Fishpond?

There i s evidence t h a t growth r a t e increases when C. v f r ~ i n i c a spats a r e

cultured i n chemically f e r t i l i z e d water a t a shallow depth.

STATEMENT OF THE PROBLEM

The summer months a r e t he na tu r a l spawning months of t he oyster . If

spawning could be induced during t h e winter o r o f f seasons this would add

greatly t o oys te r production. Various techniques a r e being t e s t e d on

the marketable oysters .

Objectives :

This study seeks t o answer the questions:

1. Can marketable s i z e oysters be induced t o spawn during t h e winter /+-

o r o f f season months?

2. Which technique(s) r e s u l t s i n the most e f f i a e n t spawning?

METHODS OF CONDUCTING STUDY

c- - a oysters were placed i n experinenta,- tanks* Each t a r k

ha 25 oys te r s which were subjected t o the various spawning techniques.

The spawning techniques:

I. ?% Potassium Chloride

. Subject the oysters t o water of a 1% KCL concentration

2. 1% Potassium Iodine

Subject the oysters t o water o f 1% K I concentration

3. E l e c t r i c Current

Subject oysters t o a weak e l e c t r i c current

4. Heat and crushed oys te r

Line t h e tank with tarpaper t o i n su l a t e heat. Crush t h r ee oys te r s

and r e l ea se in the tank. Use heat lmips and raise temperature

t o 350C.

OUTLDE OF THE STUDY

I. Materials and Equipment Used

A. Preparation of Experimental. Tanlcs

1. Four tanks

2. aireation system

B. Preparation for spawning techniques

1, Potassium Chloride

2. Potassium Iodide

3. Heat lamps

4. Electric current

5. Tarpaper

C. Collection of Data

1 Microscope

2. Glass slides and cover slips

3. Eyedropper

11. Procedure

A. Ekperimental tanks

1. Place 25 marketable oysters in 4 expnrimental trays

2. Introduce aireation system

3. Subject to various spawning techniques

B. Collection of Data

1. Observe the reaction of the oysters

2. Examine water to determine spawning

A t the end of the 4 - 2 how experimental periods the reaction o f

the oysters t o spawning techniques were evident.

Tank Spawning Reaction Deaths Original Techniques S ~ ~ n p l e

1 1% KCL Negative 5

2 1% K I Negative 3

3 Electr ic Current Negative 0

4 Heat and Crushed Positive 0 Oyster

As a resolt of the spawning study, it i s evident t h a t C. virqinica

oysters can be induced t o spawn during the winter of off seasons, by the

use of the Heat and Crushed Oyster technique.

DISCUSS ION

Altho~igh spawning was induced by the use of the heat and crushed

oyster techniques, t h i s technique may not be the only method f o r II.

inducing oysters t o spawn. Fossibly, the heating of the water may

resemble the warmth of s-er weather. A s the oysters a re crushed

there nay have or a c t a s a hormone t o induce the spawning of the

oysters.

*-

PROJECT COILTCLUS ION

From the results of the data taken from my experimental phases it

i s evident that the variat ion of depths, s a l in i ty , and d i e t has an

e f fec t on the growth and conditioli index value of C. virginica.

The best growth and condition index value can be reached by the

subjection o f ' C . v i r ~ i n i c a spats t o e i the r processed fcod o r chemically

f e r t i l i z e d water a t a r e l a t ive ly shall o w depth and re la t ive ly low

sa l in i ty .

APPLICATION

The r e s u l t s o f these experiments may help e s t ab l i sh an oys te r na r i cu l t u r e

Industry i n Hawaii. A t present my fa ther , t h e operator of 14olii Fishpond,

i s se r ious ly considering t h e p o s s i s b i l i t y of es+abl ishing an oys te r mariculture

indus t ry i n our fishpond.

For a p rac t i c a l , e f f i c en t , and pro f i t ab l e oyster mariculture indus t ry

t h e use of chemical f e r t i l i z e r i n an a rea of low s a l i n i t y and i n shallow

water w i l l r e s u l t i n t h e f a s t e s t growth and bes t condition index i n Mol i i "-4.

Fishpond.

LT2"FAATURE CITED

1. Field Enterpr ises Educational Corporation, 1965. Wstc.r, pages 681 - 683.

World Book Encyclopedia, Volume 14, N-0.

2. F i f t h Legis la ture of the S t a t e of Hawaii , 1970. S ta tus and Progrcss

Report of t h e Commercial Oyster Fishery Development Invest igat ion

being conducted by t he Division of Fish and G me, Department of Land

and Natural Resources, pages 7 - 10.

3. Mackenzie, Clyde L. Jr., f"i'he Oyster Culture Modenization i n Long Islmd

dCI Soundtt. The American Fish Farmers and iJorld Aquaculture Nem, Pages

1 - 14, 1970.

4. May, Edwin B. " F e a s i b i l i t y of Off Bottom Oyster Culture i n A1eba.m."

Alabama Marine Resources Bullent , number 3, pages 1 - 10.

5. Sakuda, Henry, M. llCondition of American Oyster". Crassostnea

v i r ~ m c a I n West Loch, Fea r l Harbor, Hawaii, Volume 95, IJumber 4,

p a g e 426 - 429. /' '

6. Sakuda, Henry M. tlPreproductive Cycle of American Oyster." Crassostrar:

.-* v i r ~ i n i c a i n Wsst Loch Pear l Harbox, volume 95, number 2, pages 21 6 - 21 8 .

7. Sparks, Alber t K. ItSurvey of t h e Oyster Po t en t i a l of Hawaii. Strite

of Hawaii Department of Land and Natural Resources , pages 1 -42.

8. Ronald T. Acton and E. Edward Evens. "Bacteriophage Cleasrance i n t h e

Oyster (Crassostrea v i rg in i ca ) . I t Journal of B a ~ t ~ e r i o l o m , Apri l 1968,

pages 1260 - 1266, volume 95, number 4.

9. Victor Loosanoff and Harry Davis. "Rearing of Bivalves Molluslts."

Advances i n k i n e Biology, volume 1, pages I - 130.

10.Ronald T. Acton, E. Edward Evans, and Claude Bennette. "Irmamological

Capabi l i t i e s of the Oyster Crassostrea vi rginica . I r Corn. Biochem, PkvsioL.,

1969, volume 29, and pages 149 - 160.

M r . George H. Uyemura ( fa ther ) - grant ing me t h e permission t o conduct

my experiments i n Molii Fishpond, use of boat t o c o m t e t o t r ays , and

he lp with heavy manual work.

Mr Alvin ?Jon (advisor and in s t ruc to r ) - loan of gram scale, drying

oven, microscope, Winker t i t r a t i o n equipment, and he lp with correct ion o f

write up.

Mrs. Carol F u j i t a (science club advisor) - loan of mi l l ipore micro- ,err

biology equipment.

Mr. Henry Sakuda and Mr. Paul Kawamoto (Department of F i sh and Game

Hawaii) - loan of background information concerning oysters, condit ion

index formula, and coliform checks.

D r . Ronald T . Acton ( ~ n s t m c t o r a t t h e Ca l i fo rn ia I n s t i t u t e of

Technology) - Background information concerning oys te r s .

M r . J. D. Costlow, Jr. ( I n s t r u c t o r * a t Duke Universi ty

Laboratory) - Background information concerning oysters . cY-

Mr. Douglas Char ( ~ c a c h e r Assist cen te r ) - Helped with p ro jec t

display.