katoh 1982 aquacultural-engineering

7/28/2019 Katoh 1982 Aquacultural-Engineering

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Aquacultural Engineering 1 (1982) 35-44

A C A S E F O R F I S H E R I E S E N G I N E E R I N G A N D I T S A P P L I C A T I O NT O T H E P L A N N I N G O F C O A S T A L A Q U A C U L T U R E F A C I L I T I E S

I N J A P A N

JUICHI KATOHLaboratory o f Environ mental Hydraulic Engineering, Dep artme nt o f Marine Environ men talScience and Technology, To kyo University o f Fisheries, 5- 7 Konan-4, M inato-ku,

Tokyo 108, Japan

A B S T R A C TFisheries engineering concerns the development of the fisheries industry. It has not yetbeen systematized because the problems raised are so diverse and it is not easy toprovide an organic link be tween the biological and engineering sectors. This paper isintended to present a definition and the significance or characteristics o f fisheriesengineering and to propose a methodology for it.The gist o f this paper is." (1) the aim o f fisheries engineering is to buiM up theenvironmental conditions for the forms o f marine life concerned and (2) the six basicpoints which are derived serve as principles which shouM be applied to any kind ofproblem.

FISHERIES ENGINEERING

There a r e a subs t an t i a l l y l a rge nu m ber o f a r t i c le s dea l ing e it he r comp rehens ive ly o rpa r t i a l l y w i th t he de s ign and con s t ruc t i o n o f coas t a l aquacu l tu r e f ac il it ie s . I t appe a r stha t t he de s ign o f such f ac il i ti e s i n some o f t he se a r ti c le s cou ld be im prov ed on b y t heapp l i ca t i on o f c iv i l eng inee r ing t e chn iques . The need fo r such eng inee r ing t e chn iqueshas a r i s en f rom the f ac t t ha t conven t iona l de s igns worked ou t by s imp le ca l cu l a t i onso r p r ep a red emp i r i c a l ly by i n tu i t i on can no l onge r keep up wi th t he p rog re s s o f aqua -cu l t u r e and m ee t t he r e su l t an t dem and s fo r g r ea t e r d ive r s i ty o f p rod uc t s a s we l l a s f o re x p a n s i o n a n d f u n c t i o n a l i m p r o v e m e n t o f t h e f a c i l i t i e s . T h i s f a c t w a s p o i n t e d o u t a tt h e F A O c o n f e r e n c e o n c o a s t a l a q u a c u l t u r e h e l d i n N o v e m b e r 1 9 7 0 i n B a n g k o k .

Am ong the m an y r epo r t s and wr i ti ngs pub l i shed i n the pa s t , t he r e a r e some wh ichcan b e h igh ly va lued fo r t he a u tho r s ' e f fo r t s t o g ive en l i gh t en me n t on f i she r ie s eng in -

35Aquacul tural Engineering 0144-8 609/82/000 1-0035/$0 2.75 Applied Science Publishers Ltd,England, 1982Printed in Great Britain


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36 J . KATOH

e e r in g b y a d o p t i n g h y d r a u l i c a n d m a r i n e e n g i n e e r i n g d a t a a n d gr a p h s. N e v e r th e l e ss ,o n e c a n n o t d e n y t h a t t h e e l a b o r a t i o n o f t he s e a u t h o r s , w h o m a y b e e x p e r t s i n t h ef i e ld s o f e n g in e e r in g , d o e s n o t f u l l y a n s w e r t h e d e t a i l s r e q u i r e d b y f i s h c u l t u r e .

T h e f i r s t s t e p i s t o e x a m i n e w h a t c i v i l e n g i n e e r i n g h a s t o d o w i t h a q u a c u l t u r e . T oa n s w e r t h e p r o b l e m o n e n e e d s t o k n o w t h e d e f i n i t i o n o f civ il e n g i n e e r in g a n d h o w iti s s y s t e m a t i z e d . C iv il e n g in e e r in g i s d e f i n e d a s a f i e ld o f e n g in e e r in g c o v e r in g p l a n n in g ,d e si gn a n d e x e c u t i o n o f w o r k , o p e r a t i o n , a n d m a i n t e n a n c e a n d m a n a g e m e n t , w h i c ha re a ll r e q u i r e d f o r t h e c o n s t r u c t i o n , i n st a l la t i o n a n d d e v e l o p m e n t o f s tr u c t u r e s a n de s t a b l i s h m e n t s ( Y a s o j i m a , 1 9 7 3 ) .

T h e ' s t r u c t u r e s ' r e f e r r e d t o h e r e in d i c a t e t h e a rt if i ci a l s t a t i o n a r y c o n s t r u c t i o n s s u c ha s e m b a n k m e n t s , b r i d g e s a n d s l u ic e s w h ic h a r e , a s a r u l e , i n t e n d e d f o r s o m e s p e c i f i cp u r p o s e . O n t h e o t h e r h a n d , t h e t e r m ' e s t a b l i s h m e n t s ' r e f e rs t o a n u m b e r o f s tr u c t u r e sw h i c h a r e c o m b i n e d t o g e t h e r t o e x h i b i t a c e r t a i n s p e c if i c f u n c t i o n . C u l t u r e p o n d s a n dh a t c h in g f a c i li t ie s a re s u c h e s t a b l i s h m e n t s . ' D e v e lo p m e n t ' a s u s e d in t h e f i e ld o f c i vi le n g i n e e r in g i s th e e n d e a v o u r t o a c h i e v e t h e s p e c if i c o b j e c t iv e b y s u i ta b l e c o m b i n a t i o na n d i n t e g r a t i o n o f s t ru c t u r e s a n d e s t a b l is h m e n t s .

T h e d iv i s io n s l i s te d i n T a b l e 1 a r e g e n e r a l l y a c c e p t e d i n t h e c ivi l e n g in e e r in g s y s t e m ,b u t a g r i c u l t u r a l e n g in e e r in g ( o r a g r i c u l t u r e c iv i l e n g in e e r in g ) is a ls o p l a c e d i n t h i sc a t e g o r y . I n a d d i t i o n , t h e r e c e n t w o r l d a f f a ir s n e e d d i s a s t e r- p r e v e n t i o n e n g i n e e r i n g a n da ir o r w a t e r p o l l u t i o n c o n t r o l e n g i n e e r i n g as n e w a p p r o a c h e s t o h u m a n w e l f a r e.

B y a c c e p t i n g t h e c o n c e p t o f c la s s if i c at i o n a s a d v o c a t e d i n T a b le 1 i n th e s a m ec o n t e x t f i s h er y e n g i n e e ri n g m a y b e c a t e g o r i z e d ( a q u a c u l t u r e e n g i n e e ri n g , f is h i n gg r o u n d d e v e l o p m e n t e n g i n e e ri n g , e t c .) . H o w e v e r , t h e c iv il e n g in e e r i n g i n v o lv e d i n t h ef i s h e ri e s o r a g r i c u l t u r e i n d u s t r y i s, in i t s d e f i n i t i o n , d i f f e r e n t f r o m th e o t h e r civ ile n g in e e r in g d iv i s i o n s s h o w n in T a b l e 1. Be c a u s e t h e f a c to r s t o b e h a n d l e d i n th ep l a n n in g o f f i s h e ri e s w o r k s a r e m a n y ( e . g. b io lo g i c a l p r i n c ip l e s a s w e l l a s d e l i c a t e d a i l ye c o n o m i c p r o b l e m s ) t h e c iv il e n g i n e e r a l o n e c a n n o t a n s w e r t h e p r o b l e m s p o s e d b yf i s h e ry w o r k s .

TABLE 1Disciplinary divisions of civil engineeringSections Divisions

Structures: Bridge engineering; Tunnel engineering; Fo und atio n engineering; DamengineeringEstablishmen ts: Railway engineering; R oad engineering; Traffic engineering; River engineering;Power-generation engineering; Water system engineering; Harbourengineering; Coastal engineering; Exterior of cons truction and natureconservationDevelopments: Land development engineering; Rural development engineering; Urbandevelopment engineeringBasic problems: Quality and durability engineering; Hydrau lic engineering; Hyd rologicalengineering; Soil mechanics; Fo und ation engineering


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A C A S E F O R F I S H E R I E S E N G I N E E R I N G I N J A P A N 3 7

C i vi l e n g i n e e r i n g , a s i t s d e f i n i t i o n i m p l i e s , i s c o n c e r n e d w i t h t h e i m p r o v e m e n t o f t h ew e l f a r e o f h u m a n s o c i et y . I n d i r e c t l y f i s h er i e s o r a q u a c u l t u r a l e n g i n e e r i n g d e r i v e d i tsm e a n i n g f r o m i t, e x c e p t t h a t , th e i m m e d i a t e c o n c e r n i s n o w t o im p r o v e t h e p r o d u c -t i o n o f a q u a t i c l if e . T o a c e r t a i n e x t e n t , t h e m e t h o d s o f t r a d i t i o n a l c iv i l e n g i n e e r i n ga re e m p l o y e d i n t h e s o l u t i o n o f th e a q u a c u l t u r a l e n g i n e e r i n g p r o b l e m s .

A q u a c u l t u r e i n a b r o a d s e n s e m a y b e c la s s if i ed b y t h e s p e c ie s t o b e c u l t u r e d , a n df i s h c u l t u r e a s a w h o l e m a y b e d i v i d e d i n t o t w o c a t e g o r i e s - f r e s h w a t e r a n d s e a w a t e r( i n c l u d i n g b r a c k i s h w a t e r ) c u l t u r e - b y t h e w a t e r m e d i u m u t i l i z e d . A g a i n , f i s h c u l t u r ei n J a p a n m a y b e c l a s si f ie d i n t o t w o c a t e g o r i e s - c u l t i v a t i o n a n d p r o p a g a t i o n . I n T a b l e 2t h e c u l t i v a t i o n a n d p r o p a g a t i o n a re p r e s e n t e d g r a p h i c a l ly b y th e t e c h n i q u e s a d o p t e da n d t h e w a t e r m e d i u m u t i l i z e d . T h e c o m p a r i s o n i s a t t e m p t e d o n l y o n f r e s h w a t e r f is hc u l t u r e ,

R e c e n t l y ( M i l n e , 1 9 7 2 ) a n o t h e r m e t h o d o f c l a ss i f i c a ti o n b a s e d o n t h e e n v i r o n m e n tw a s p r o p o s e d . A q u a c u l t u r e m a y a l s o b e cl a s si f ie d b y t h e l o c a t i o n s o n t h e c o a s t a ss h o w n i n T a b le 3 .

E a c h o f t h e s e s c h e m e s h a s i t s o w n a d v a n t a g e s . B e t h a t a s i t m a y , a q u a c u l t u r a le n g i n e e r i n g ( f is h e r i e s e n g i n e e r i n g ) i s f o r c e d t o r e s p o n d t o a w i d e r a n g e o f e n g i n e e r i n g

T A B L E 2C o m p a r i s o n o f f is h c u l t u r e , c u l t iv a t i o n a n d p r o p a g a t i o n a c c o r d i n g t o t h e s p e c if i c t e c h n i q u e sa d o p t e d a n d t h e b o d i e s o f w a t e r u t il iz e d : m o d i f i ed f r o m K u r o n u m a ( 1 9 5 4 )

Waters River Lake Swamp Reser- Paddy Fish-voir pondTechniques TechniquesEgg t a k ing x x x x x x B r e e d im p r ov e m e n tx H a t c h i n g x x x x x x T r a n s p o r t a t i o n xF r y c o l l e c t i on x x x x x x S a m eS t o c k i n g + + + + 0 + 0 + P o n d c o n s t r u c t i o nT r a n s p l a n t i n g + + + + 0 + 0 + S t o c k i n g0 0 F e r t i l i z a t i on+ E n v i r o n m e n t i m p r o v e m e n t + + + + 0 + 0 + F e e d i n g 0S t o c k a s s e s s m e n t + + + + 0 0 D e n s i t y c o n t r o lM a n a g e m e n t + + + 0 D i se a se t r e a t m e n tF i sh ing + + +0 +0 0 0 H a r ve s t

T A B L E 3A c l a s s i f i c a t i on o f c oa s t a l a qua c u l tu r e1 . C u l t i v a t i o n o n t h e s h o r e l a n d G r o w i n g p o n d a n d b r e e d i n g o f s e ed l in g2 . C u l t i v a t i o n i n i n t e r t i d a l z o n e L a r v a c u l t u r e o n b r u s h , o y s t e r f e n c e c u l t u r e , e t c .3 . C u l t i v a t i o n i n s h a ll o w w a t e r C u l t i v a t i o n u t i li z i n g w a t e r c u r r e n t s a n d f l o w4 . C u l t i v a t i o n i n m i d l a y e r a n d o n b o t t o m F i s h s h e l te r , s e a w a t e r f a r m i n g5 . C u l t i va t i on i n su r f a c e w a te r F loa t in g c a ge o r ba sk e t , e t c .


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38 J . K A TO H

prob lems as show n in Table 3 . The author clas si fi ed those problem s by purposes inTable 4.

Furtherm ore, when aquacultural engineering develops and needs to be subdivided,i t seems that the class i f icat ion system based on disciplinary divis ions as sho wn inTable 1 w ou ld st il l apply.

T A B L E 4Fisher ies engineer ing( I ) I N T R O D U C T I O N

(I I ) S T R U C T U R E E N G I N E E R I N Gl . A qu acu l tu ra l s t ruc tu re( 1) A q u a c u l t u r a l p o n d(2) W ater supply and drainage sys tem(3) Others2 . S truc ture for f ish ing po r t(1) Character is t ics of the s t ructure(2 ) H ydrau l i cs o f the po r t bas in(3) Others3 . Oth er subjects

( I I I ) E N V I R O N M E N T P R O T E C T I O N1. Seawater exchan ge2 . D i f fus ion and mix ing3 . A era t ion(IV ,) D E V E L O P M E N T O F F I S H E R I E S1 . A quacu l tu re(1) Ar t i f ic ia l reef(2) Ar t i f ic ia l t idelan d(3) Others2 . Wave con t ro l(1) Brea kw ater for f isheries(2) F loa t ing b reakw ate r3 . O ther subjects{V ,) O U T L I N E O F H Y D R A U L I C E N G I N E E R I N G W O R K P L A N N I N G1 . M ethods o f inves t iga t ion2 . M ethods o f p red ic t ion

3 . The ory o f p lann ing4 . Techno logy as s ess men t

P R IN C IP L ES O F P L A N N I N G , D E S I G N IN G A N D C O N S T R U C T I O NN e e d l e s s t o s a y c i v il e n g i n e e r i n g a t la r ge a i m s f o r t h e i m p r o v e m e n t o f s o c ia l w e l f a re .I n t h e c a se o f a q u a c u l t u r e t h e d e s i g n i n g c r i t e ri a fo r t h e o b j e c t i v e o f f i sh p r o d u c t i o na re n o t n e c e s s ar i ly f u l ly p r o v i d e d , a c c o r d i n g l y t h e f u n d a m e n t a l p l a n n i n g o f t h e p r o j e c tm u s t b e e s t a b l i s h e d f i r st . T h e c r i t e r i a v a r y d e p e n d i n g o n t h e s p e c i es h a n d l e d , l o c a l i t y


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A C A S E F O R F I S H E R I E S E N G I N E E R I N G I N J A P A N 39and season as well as regional status. The fundamental planning of the project, how-ever, is believed consistent irrespective of aquaculture types and the kind of engineeringwork adopted in the fisheries project.

The fundamental planning may be categorized into six parts as explained below.

The object o f aquacultural engineering is to be clarifiedConstruction and development of aquaculture establishments and structures is

intended to create an environment in which the production o f aquatic animals andplants can be improved in both quantity and quality.

In general any civil engineering work sets limits on itself, and endeavours are madein the designing stage to provide sufficient rigidity and strength, cutting down the costto a minimum, but still having the assurance of durability after completion. Civilengineering in fisheries should naturally be carried out with the same endeavours andwith the clearcut recognition that the work is a means of fisheries development. Lackof this recognition often makes the finished structures and establishments almostuseless or of low efficiency.

Environmental survey - from an environmental hydraulic engineering viewpoMtExecution of civil engineering work in fisheries must be preceded by the establish-

ment of the designing criteria, and this calls for the clarification of the environmentalcondit ion best suited to the growth of the species under consideration. To be morespecific, a careful prior study should be made on the ecology, physiology, diseases,and empirically established management method (e.g. breeding and growing, etc.).

Aquatic animals grow and live in different environments and they are generallylower organisms. For this reason, their physiology and manifestation of characters areprone to and show wide adaptability to the changes of the environmental condition.It would be ideal, therefore, if these characteristics (relationship between nutrition andphysiology and their environment, etc.) could be clarified before hand, and theenvironmental factors affecting qualitative as well as quantitative improvement ofcharacters could be examined for the establishment of an 'improved type of aqua-culture'. In actuality, however, such characteristics are still not fully understoodexcept for very few fish species, and no light has yet been cast on the life cycle ofmany of the species of aquatic animals. This means that investigations should be con-ducted from every angle in future to bring light on the effect of environmental condi-tions on nutrition, physiology and pathology as well as natural enemies.

Although survey items will be confined to engineering aspects, it must be borne inmind that the surveys are intended primarily for the increased production of animals.Surveys should be conducted along scientific lines.

It is often the case that they are carried out in a formalistic manner by fisheriespersonnel due to administrative restraints and customary practices. Degeneration intoformalism is also often observed in the mechanical compilation of data by month and


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40 J. KATOHyear group, which is not sufficient to understand actual status. What counts most isnot such formalism but the collection of data by the method which actually promisessubstantial development of the specific fish cultivation under consideration. Toelaborate the fact it may be stated that the hydraulic data requires that the surveysbe made vertically and by areas affected by tidal changes. As to the periodicity orseasonal surveys, they should be determined by the critical time for aquaculture opera-tion, for instance, at the time of stocking, peak growing and harvesting, etc.

The importance of such data will be better understood from the criteria surveyitems and the survey methods shown in Table 5.Phys i ca l- eng ineer ing 'E f f e c t i v e and De fec t i v e Fac to r s ' (E .D .F . ) wh ich a re m os ti m p o r t a n t o r d o m i n a n t f o r p r o d u c t i v i t y a re t o b e c le a r ly d e f i n e d

Destructive factors or the important key points in the project planning should begrasped clearly.Surveys cast light on a number of defective factors for the productivity, either

directly or indirectly, as well as on important points to be considered in the projectplanning. It is desirable to execute a design in which all destructive factors are excludedand all important points are given full consideration. Generally, however, a decision ismade on one or two such factors or points. Usually the factors or points 'thus deter-mined are closely interrelated with each other.A n a l y s is o f E . D . F .

Analysis and review of such factors and points formulate the major point o f thesuccessful planning work.If the flow condition (i.e. velocity, flow direction, depth, etc.) is a major factor that

accelerates wear and degradation, a condition free from this factor should be artifici-ally created. In this case, levdes or other structures should be constructed by civilengineering work after perhaps a model test and similarity comparison.

If, on the other hand, water quality is the detrimental factor, then, mixing anddiffusion of water becomes the main theme of study and investigation. This civilengineering work is now required for the creation of cultivation media with environ-mental conditions. This work can be considered as a branch of fisheries engineering,and applies to all civil engineering carried out for aquaculture projects.Re la t i on be tween p roduc t i v i t y and E .D .F . i s t o be c la r i f i ed

It is important to know how productivity can be affected by defective factors ormajor planning points. This calls for investigations, model experiments and data analysiswhich should all be conducted before embarking on the actual construction work; itmay be said in this process that engineering techniques are considered critically for thefirst time in aquaculture.

Investigation of the magnitude and nature of defective factors should be followedby the assessment of their influence on productivity. I t is no exaggeration to say that


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42 J . K A T O Hthe success of c iv i l engineer ing work in the f ie ld of aquacul ture h inges on suchinves t iga t ion .

In J apan , cons ide r ab l e e f f o r t s have been ma de fo r c la r i f i c a ti on o f de fec t i ve f ac to r s ,bu t i t c anno t be s a id t ha t t he i r mean ing i s p rope r ly eva lua t ed . Th i s i s because t her e la t io n s h i p b e t w e e n s u c h f a c t o r s a n d p r o d u c t i v i t y h a s n o t y e t b e e n w e ll u n d e r s t o o d .C la r i f ic a t i on o f t he r e l a t i onsh ip i s a p ro b l em tha t aw a i t s ou r f u r t he r and co ns t an t s t ud i es .

I n a n a t t e m p t t o b r in g a s o l u t io n t o t h e p r o b l e m t h e f ol lo w i n g t w o m e t h o d s m a y b econs ide r ed .

1 . M e thod i n wh ich t he nu t r i t i on and phys io log y o f the sub j ec t an ima l is exam ineda t l abo ra to r y l eve l w i th fu ll a ccou n t t ake n o f i ts p rodu c t i v i t y , and t he r e su lt sob t a ined a r e com pare d w i th t he de f ec t i ve f ac to r s f o r c l a r i f ic a t i on o f gene ra lchara c te r i s t ics of the sa id re la t ionship .

2 . M e thod i n wh ich t he p ro duc t i v i t y o f the sub j ec t an ima l in i ts na tu r a l hab i t a t i si nves t iga t ed by f ie l d and l abo ra to ry s t ud ie s .

M e thod 1 i s pu re ly a b io log ica l p roced u re i n t ended t o s t ud y t he gene ra l cha r ac -t e r is t i c s o f t he sub j ec t an ima l , and is advan t ageous in t ha t i t c a s ts li gh t on m an yphys io log i ca l and o the r f a c t s. How eve r , i t is c l e a r t ha t t he l abo ra to r y t e s t s invo lved i f f icu l t ie s f o r co r r e c t j udgem en t on t he ph ys io log y o f t he an ima l s , because it isu sua l l y i n f l uenced l a rgely by t he n a tu r a l env i ronm en t i n wh ich t he y li ve . Th i s r ende r si t d i f f icu l t t o unve i l t he ma n i f e s t a t i o n o f the cha r ac t e r i s t ic s in i ts na tu r a l hab i t a t , sotha t p r ac t i c a l app l i c a t i on o f t he f i nd ing i s o f t en made imprac t i c ab l e .

M e t h o d 2 , o n t h e o t h e r h a n d , i s i n t e n d e d f o r m a c r o s c o p i c s t u d y o f t h e a r e a c o v e r e dand c onse quen t l y i s c apab l e o f imp rov ing p rodu c t i v i t y f o r a sho r t pe r i od . How eve r , i th a s i t s o w n d e m e r i t , v i z . t h e c o m p l e x i t y o f n u m e r o u s f a c t o r s o f t e n l e a d s t o t h eo m i s s io n o f t r u ly i m p o r t a n t e l e m e n t s .

Hence , i t i s de s i r ab l e t ha t t he two me thods be emp loyed i n pa r a l l e l f o r compara t i ves tudy o f t he r e su l t s ob t a ined .

A t an y r a t e , i t is o f p r ime im por t a nce t o i nves t i ga te t he r e la t i ons be tw een p roduc -t ion a nd defec t ive fac to rs in d i f fe ren t a reas and seasons . I t i s no ted th a t the inves tiga-t i on shou ld be con duc t ed fo r t he yea r , ma rk ing t he ave r age o f annua l p roduc t i v i t yga ined subs tan t ia l ly in ex tend ed per iods . I f th i s i s no t feas ib le , i t i s necessary to se lec ta number o f yea r s when t he p roduc t i v i t y i s be l i eved c lo se t o t he ave r age .

The inves t iga t ion descr ibed above provides the bas i s for assess ing the product iv i ty ,c l a r if y ing t he cause s o f p rodu c t i on f l uc tua t i on , and e s tab l i sh ing the con d i t i ons fo rp ro j ec t p l ann ing a s exp l a ined be low.Establishment of rational planning and designing policies

I n t he de s ign ing and p l ann ing s t age , f o ll owing t he p roce du re ab ove , due cons ide r a -t i o n s h o u l d b e g iv e n t o e c o n o m i c a n d a d m i n i st r at i v e r e q u i re m e n t s f r o m t h e v i e w p o i n to f c i v i l eng inee r ing i n o rde r t o p roceed w i th t he execu t i on o f work .


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4 4 j . K A T O HW h e n e s t i m a t i o n o f t h e b e n e f i t d e r iv a b le f r o m e n g i n e e r i n g w o r k i s c o m p l e t e d , t h e

r e g i o n a l s o c i o - e c o n o m i c c o n d i t i o n s a r e s u b j e c t e d t o a r i g i d a n d c o m p r e h e n s i v e a n a l y s i sl e a d in g t o a c o n s t r u c t i o n p r o j e c t e s s e n ti a l t o t h e r e g io n a l f is h e ri e s d e v e l o p m e n t .

I n o r d e r t o d er iv e f u n d a m e n t a l s o f p r o j e c t p l a n n i n g w h i c h a r e re a d i l y u n d e r s t o o da n d s a ti s fi e d , t h e a u t h o r i n v i te s c o n s u l t a t i o n t o t h e f o r m a t p r e s e n t e d i n T a b le 5 . B yf i ll i n g t h e f o r m a t p r o v id e d b y t h e r e q u i r e d d a t a it i s p o s s ib le t o g ra s p t h e d e s ig nc r it e ri a w i t h o u t t o o m u c h d i f fi c u lt y . U s e o f th i s f o r m a t i s s t r o n g ly r e c o m m e n d e d ,b e c a u s e t h e l a c k o f s u c h f u n d a m e n t a l d a t a c a n h a r d l y i n t r o d u c e c iv il e n g i n e e r in gt e c h n i q u e s i n t o t h e f i e ld o f a q u a c u l t u r e .

T h e s i x i t e m s d e s c r ib e d a b o v e a r e i l l u s t r a t e d i n F ig . 1 .

R E F E R E N C E SYasojima, G. (1973). Introduct ion to Civil Engineering, Gihodo, p. 1.Kuron um a, K. (1954). Significance of propagation and cultivation (in Japanese). Aquaculture, 1

& 2 .Milne, P. H. (1972). Fish and Shellfish Farming in Coastal Waters, Fishing News Ltd, London,p. 15.

katoh 1982 aquacultural-engineering

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