Larrivee 1983 Aquacultural-Engineering

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Aquacul tural Engineer ing 2 (1983) 247-262

Th e D e s ig n a n d De v e lo p m e n t o f a L if e S u p p o r t in gS y s t e m f o r E x p e r i m e n t i n g o n S a l m o n i d sDenis Larriv6e

D6p artement des Sciences Fondam entales , Univers it6 du Qu6bec h C hicout imi ,Chicoutimi, Qu6bec, Canada G 7H 2B 1

J a c q u e s L a p i e r r e a n d L a u r e n t B e r t h i a u m eD 6partem ent de Virologie, Insti tut Arm and-Frappier, Laval-des-Rapides,

Qu6bec, Canada H7N 4Z 3

A B S T R A C TThis s tudy concerns the deve lop me nt and the t e st ing o f a s y s tem whichperm its in tens ive rear ing o f aquat ic animals. The sys tem of fers pract icaloppor tuni t ies for var ious exper imental s i tuat ions , suf f ic ient carry ingcapa city to allow statis t ical analysis, ease o f operation, a nd insures th es tabi l i ty necessary fo r exper im ental in terpre tat ion. I t has the advantageso f be ing cons t ruc ted a t a low cos t and o f o f f er ing grea t f l ex ib i l i ty . Exper i -men ts have been conduc ted for t e s t ing the s y s tem wi th the brook t rou tSalvelinus fontinalis, which have demonstrated i ts reliabili ty . It is shownthat s tructural and fun ct ion al characterist ics o f th is cul tur ing sys temperm i t the under l in ing o f aspec ts o f growth and hea l th wh ich are d i f f i cu l tto analyze in similar studies.

I N T R O D U C T I O NT h e s y s t e m r e q u i r e m e n t s f o r i n te n s i v e e x p e r i m e n t a l c u l tu r e o f f is h a n df is h l ar v ae h a v e b e e n t h e s u b j e c t o f n u m e r o u s p u b l i c a t i o n s ( P r e v o s t,1 9 4 0 ; B u r r o w s a n d P a l m e r , 1 9 5 5 ; H a s k e ll , 1 9 5 9 ; A l d e r d i c e e t a l . , 1 9 6 6 ;A l d e r d i c e a n d V e l s en , 1 9 6 8 ; B u r r o w s a n d C o m b s , 1 9 6 8; B u r r o w s a n dC h e n o w e t h , 1 9 7 0 ; B u s s e t a l . , 1 9 7 0 ; B r e t t e t a l . , 1 9 7 1 ; B u s s a n d M i l le r ,1 9 71 ; C a r l s o n a n d H a l e , 1 9 7 3 ; L a r m o y e u x a n d P i p e r , 1 9 7 3 ; R e e d e t a l . ,1 9 7 3 ) .

247Aquacu l tura l Engineer ing 014 4-86 09 /8 3 /$0 3 .00 Applied Science Publishers Ltd,England, 1983 . Printed in Gre at Britain


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248 D. Larrivde, J . Lapierre, L. BerthiaumeAmong the large variety of culture enclosures which have been found

suitable for rearing fish one can name aquaria small raceways or labora-tory streams, planktonkreisel, double cuvette plankton rotor andothers. The objectives pursued in these culture systems may vary, buta system ideally suited for exper imen tati on should possess characteristicssuch as to offer:

(1) a spectrum of practical experimental situations;(2) uniformit y throughout ( for a given set of conditions);(3) sufficient carrying capacity to permit statistical interpreta tion;(4) optimization capabilities for self-cleaning and prevention of

pathogens;(5) low cost and easiness of operation .

In order to achieve these, and in relation to a specific research projecton the sensitivity of the brook trout S a l v e l i n u s f o n t i n a l i s to the infecti-ous pancreatic necrosis virus (IPN), we developed a simple culturesystem, which allows good stability of operation. Temperature can becontrolled over a range of 20C to 4C and the system offers optimalconditions for maintaining large numbers of fish under different experi-mental situations. The results we have obtained for some time now aresufficiently clear to guarantee the reliability of the system. An evalua-tion of the parameters indicates that its design can be applicable todifferent experimental needs.

OBJECTIVESThe immediat e objectives of the research project were:

(a) The relationship of age to the pancreatic necrosis virus infec tionunder dif ferent temperatu re conditions.(b) The relative import ance of environmental factors (physico-chemical, biological) in the induction o f this pathology.

(c) The mechanism of the virus vertical transmission in relation todevelopmental age from egg to small fry.

Wider objectives concerned the studies on: (1)growth and survivalof the fish under optimal conditions; (2) nutritional requirements;(3) behavior under normal and experimental conditions at differenttemperatures; (4) the interplay of different parameters for the optimi-


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A l if e su p p o r t i n g s y s t e m f o r e x p e r i m e n t i n g o n s a l m o n i d s 249z a t i o n o f t h e b r o o k t r o u t l if e s u p p o r t i n g s y s t e m , a ll d u r i n g t h e c r it ic a lp h a s e o f h a t c h i n g t o f ir s t fe e d i n g w h e n t h e l a rg e st m o r t a l i t y r a t e i nf is h r e a r i n g o c c u r s .T h e m a i n o b j e c t i v e h e r e w a s t h e r e f o r e t o d e v e l o p a s y s t e m w h i c hc o u l d s a t is f y t h e s e re s e a r c h r e q u i r e m e n t s .

D E S C R I P T I O N O F T H E S Y S T E MW a t e r s u p p l y a n d m o n i t o r i n g ( F ig . 1 )C u l t u r e o f f is h f o r e x p e r i m e n t a t i o n r e q u i re s h i g h s t a n d a rd s o f w a t e rq u a l it y . W a t e r s u p p l y a n d m o n i t o r i n g b e c o m e s th e r e f o r e o f c ri ti c ali m p o r t a n c e . T h e w a t e r m a y c o n t a i n d i f f e re n t p a r ti c le s in s u sp e n s i o n o r

/ / ~ Z

/ ACTIVATEDCARBON FILTERi T u U ."-~ ~ ~ .....

W A T E B E , T qTHE INCUBATOR ~ ~ [ I '% ~ ! . j I"

/ I ~ ~ - . :! M ECHANICAL

~ " q ~ ' ~ W A TE R E X ITTO THE WATER TABLE

TO THE BAC

F i g . 1 . W a t e r s u p p l y f i l t r a t i o n s y s t e m .

WATER INLET

HYDROCLONE


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250 D. Larrivde, J. Lapierre, L. Berthiaurneu n w a n t e d c h e m i c a l s d u e t o a lg al g r o w t h o r w a t e r t r e a t m e n t . T h e fi shc a n s u rv iv e t h e p r e s e n c e o f a c e r t a in a m o u n t o f t h e s e in t h e w a t e rs u p p l y b u t t h e y c a n h a v e n e g a t i v e e f f e c t s o n t h e g ills ( s e s t o n o s i s ) ( W a l e sa n d E v in s , 1 9 3 7 ) a n d a f f e c t t h e r e s p i r a to r y f u n c t i o n s . M o r e o v e r t h ea c c u m u l a t i o n o f p a rt ic l e s o v e r t h e e gg c h o r i o n m a y i m p a i r t h e e x c h a n g eo f o x y g e n a n d f a v o r m i c ro b i a l g r o w t h . S i nc e o u r w a t e r s u p p l y c o m e sf r o m a m u n i c i p a l s e r v ic e , w e h a v e a l s o t o a c c o u n t f o r t h e v a r i a t io n i nt h e c h l o r i n e l ev e l. T h e d e s i g n o f t h e w a t e r s u p p l y f o r o u r s y s t e mi n c l u d e s in s e q u e n c e :

( 1 ) a m o d i f i e d h y d r o c l o n e f o r i n t e r c e p t in g t h e l ar ge p a rt ic l e s ;( 2 ) a m e c h a n i c a l f i lt e r ;( 3 ) a n a c t i v a t e d c a r b o n f i l t e r ;( 4 ) a m e c h a n i c a l f i l te r ;( 5 ) a w a t e r m i x e r ( t e m p e r a t u r e ) ;( 6 ) a w a t e r c h i l l e r ;( 7 ) a w a t e r a e r a t o r .

T h e m o d i f i e d h y d r o c l o n eT h i s c o n s i s ts o f a c y l i n d e r i n w h i c h t h e w a t e r p e n e t r a t e s w i t h c e n tr i fu g a lf o r c e s , f o r c i n g t h e l ar ge r p a r t ic l e s d o w n t h e c y l i n d e r w h e r e t h e y c a n b ef l u s h e d o u t w h i l e t h e w a t e r is f l o w i n g t h r o u g h t h e t o p .

T h e m e c h a n i c a l f i l t e r sT h e s e a re o f t h e A P 1 1 0 t y p e ( a q u a - p u re A M F C a n a d a L t d , C U N OD i v is io n , G u e l p h , O n t a r i o , C a n a d a N 1 H 7H 1). T w o m a n o m e t e r s , o n e a tt h e i n f l u e n t a n d t h e o t h e r a t th e e f f l u e n t , a l l o w t h e m o n i t o r i n g o f t h ef i l t e r p r e s s u r e .

T h e a c t i v a t e d c a r b o n f i l te rT h e m u n i c i p a l w a t e r b e i ng c h l o r i n a t e d , i t is i m p e r a t i v e t o r e m o v e a n yr e s i d u a l c h l o r i n e w h i c h is h i g h l y t o x i c t o f is h a n d f is h l ar v ae . A l t h o u g ht h e m u n i c i p a l w a t e r w h i c h w e re c e iv e d o e s n o t c o n t a i n , u su a l l y, d e t e c t -a b l e q u a n t i t y o f c h l o r i n e , o c c a s i o n a l l y i t c a n c a r r y u p t o 0 . 2 m g li te r -1o f r e s id u a l c h l o r i n e a n d i n v e r y r a re c a s e s c a n e x c e e d t h is c o n c e n t r a t i o n .T h e s y s t e m m u s t a c c o u n t f o r t h e s e v a r ia t io n s i n t h e l e ve l o f c h lo r in e .T h e c a r b o n f i l te r i s m a d e u p o f a c o p p e r p i p e 1 5 c m i n d i a m e t e r a n d3 m h i g h . A s r e p o r t e d i n t h e l i t e r a t u r e ( S m i s e k a n d C e r n e y , 1 9 7 0 ) , th e


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A l if e suppor t ing sys tem fo r exper ime n t ing on sa lmon ids 251activated carbon has several interesting characteristics. It reacts withchlorine as follows:

C + 2C12 + 2H20 ~ C02 + 4HC1It also acts as an efficient adsorbant for organic matters. Hutchins(1973) developed a design me th od for activated carbon systems whichwas called the bed depth service time (BDST) method. It shows that agraph of service time (time since start of a filter run) versus bed depth(depth of carbon tank) reveals a linear relationship. It thus has themathema tical expression:

t = a + b xwhere t = service time (h), a = intercept on t axis when x = 0, b = slopeof linear line and x = bed dept h (m).

The in terce pt a is given by the expression:

a KG In -- 1where K = adsorption rate constant, Ci = impurity (solute) concentra-tion in influent (ppm), Co = impur ity (solute) conce ntratio n in effluentat breakpoint (ppm) and In = natural logarithm.

The slope b is given by:395No

b - - -GQwhere N o = carbon effic iency (kg impur ity m -3 carbon), Q = flow rate(m a min-~ m -2) and Ci = imp uri ty (solute) con cen tra tio n in influe nt(ppm).

By substituting one obtains:t = K C i l n 1 +3 95 x

This is the BDST equation. From this equation it is seen that in orderto prolong the life of the carbon filter it is advantageous to offer adesign which maximises the bed depth. A higher bed depth has also theadvantage of being more efficient for sudden variation in the level ofimpurities. The design of our activated carbon filter, based on actual


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252 D. Larr ivde , J . Lapierre , L . Ber th iaumee s s a y s a n d c a l c u l a t i o n , i s s u c h a s t o t a k e a s h i g h a c o n c e n t r a t i o n a s1 m g l i t e r -1 o f r e s i d u a l c h l o r i n e f o r a p e r i o d o f 1 3 0 m i n .

I t is a ls o p o s s i b l e a t a n y t i m e t o b y p a s s t h e c a r b o n f i lt e r f o r c le a n i n ga n d o t h e r n e e d s . A s e r ie s o f v a lv e s a l l o w s a r e v e rs a l o f w a t e r f l o w a n dt h e t r e a t m e n t o f t h e c a r b o n b e d .

T h e w a t e r f l o w i n g t h r o u g h t h e c a r b o n f i lt e r is f i l te r e d a g a in u s i n g am e c h a n i c a l f i l te r ( sa m e t y p e a s a b o v e ) b e f o r e e n t e r in g t h e r e s e rv o ir s.T h e t e m p e r a t u r e c o n t r o l sT h e s e c o n s is t o f a w a t e r m i x e r a n d a c o o l i n g s y s t e m . B e f o r e e n t e r in gt h e t o p r e s e r v o ir s o f t h e f is h e n c l o s u r e t h e f i lt e r e d w a t e r is m i x e d w i t ha s m a l l a m o u n t o f w a r m w a t e r ( th r o u g h a t e m p e r a t u r e v a lv e 5 5 5 D ,C e n t r a l B r a s s C o . ) to o b t a i n t h e d e s i r e d t e m p e r a t u r e ( in o u r ca s e 1 5 C ) .T h e r e su l ti n g w a t e r f l o w is c h a n n e l e d i n t o o n e o f t h e t h r e e t o p r es er -v o ir s. A b y p a s s c a n s e n d w a t e r d i r e c t l y in t o t h e t h i r d re s e r v o i r w i t h o u tb e i n g m i x e d w i t h w a r m w a t e r . I n th i s r e s e r v o i r a c o o l i n g ( c h il le r )s y s t e m w i t h s p ir a l t u b i n g a l l o w s t h e w a t e r t o r e a c h 5 C i f t h e i n c o m i n gw a t e r d o e s n o t g o a b o v e 1 0 C. T h e m i d d l e re s e rv o ir , w h i c h c o m m u n i -c a t e s w i t h b o t h o u t e r r es e rv o ir s , w i ll r e a c h a n in t e r m e d i a t e t e m p e r a t u r e( 1 0 C in o u r e x p e r i m e n t ) . T h e t e m p e r a t u r e h o m o g e n e i t y t h r o u g h o u te a c h o f t h e t o p r e se r v o ir s is p r o v i d e d b y t h e a e r a t o r s y s t e m . A s u p p l e -m e n t a r y c h il le r in t h e m i d d l e t o p r e s e r v o ir o n l y f u n c t i o n s w h e n t h ei n c o m i n g m u n i c i p a l w a t e r is a b o v e 1 0 C.T h e a e r a t o rT h i s c o n si s ts o f a p e r f o r a t e d c o p p e r t u b e in t h e f o r m o f a h o o p a t t h eb o t t o m o f e a c h r e s e rv o ir . A i r is p u m p e d t h r o u g h i t, c a u s in g v i g o r o u sb u b b l i n g w h i c h b r in g s a e r a t i o n a n d m i x in g . T h e a i r s u p p l i e d h a s b e e np r e v i o u s l y f i l t e r e d a n d f r e e d o f r e s id u a l o i l i m p u r i t ie s w i t h t r a p s a n dd r y f i l t e r s .T h e w a t e r l e v e l is r e g u l a t e d b y a f lo a t i n g v a lv e o n t h e i n f l u e n t a n d b yo v e r f l o w o u t le t s . A tr a n s p a r e n t t u b e a l l o w s t h e i m m e d i a t e o b s e r v a t i o no f w a t e r le v e l in t h e r e s e rv o ir s a n d d i r e c t r e a d in g o f th e t e m p e r a t u r e f o re a c h r e s e r v o i r is p r o v i d e d .S t r u c t u r e o f th e e n c l o s u r e ( F i g. 2 )T h e l if e s u p p o r t i n g e n c l o s u r e is m a d e o f p l y w o o d c o a t e d w i t h fi b er -g la s s. I t is d i v i d e d i n t o t h r e e s e c t i o n s c o r r e s p o n d i n g t o t h e t h r e e t o p


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A l if e s u p p o r t i n g s y s t e m f o r e x p e r i m e n t i n g o n s a l m o n i d s 2 5 3

Waterchi l lerTemperreadlnc

Coldwa te rinlet

Culture . . -d i s h - "

! ........

....J,Bot tomreservo i r

Reservoir. dra in , .

Common - ". .drain

i'oepr.l'l~ t u b e' i v !M e c h a n i c a lf i l t e r

Fig. 2. Culture enclosure fo r rearing salmonids (1.9 m 0.7 4 m).

r e s e rv o i rs . E a c h s e c t i o n h a s f iv e s t o r e y s in w h i c h s e v e r al c o n t a i n e r s o fd i f f e r e n t s i z es c a n b e p l a c e d . W e h a v e u s e d f o u r c o n t a i n e r s ( N a l g e n es t e ri li z in g p a n ) i n e a c h s t o r e y . E a c h o f th e s e s t o r e y s p o s s e s s f o u r t a p s ,f e e d i n g w a t e r b y g ra v i ty t o th e c o n t a i n e r s f r o m t h e c o r r e s p o n d i n g t o pr e se r v oi rs . A c o n s t a n t f l o w w a s r e g u l a t e d b y th e t a ps . E a c h c o n t a i n e r iss o b u i l t t h a t i t p e r m i t s a r e s i d u a l v o l u m e o f 6 l it e rs o f w a t e r a n d a f l o wr a t e o f 2 0 0 m l m i n -1 w a s s e t f o r t h e f l o w t h r o u g h s y s t e m . A s w il l b es e e n b e l o w t h e s e c o n d i t i o n s i n s u r e t h e b e s t q u a l i t y o f w a t e r , w i t h n o


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254 D. L arrivde, J. Lapierre, L. Berthiaumev a r ia t io n in t h e t e m p e r a t u r e a n d c o n s t a n t o x y g e n a t e d w a t e r s u p p l y .T e m p e r a t u r e m o n i t o r in g o f t h e w a t e r in t h e c o n ta i n e rs a t t h e d i f fe r e n ts t o r e y l ev e ls h a s s h o w n a v a r i a ti o n o f le ss th a n 0 . 3 C b e t w e e n t h e t o pc o n t a i n e r s a n d t h e o n e s a t t h e l o w e r le v el s.

A s t h e w a t e r i s d i s t r i b u t e d i n d i v i d u a l l y i n e a c h c o n t a i n e r i t a l soc o m e s o u t a n d is re j e c t e d i n d i v i d u a l l y f r o m e a c h o n e . I t is d i r e c t l yr e j e c t e d i n t o a b o t t o m r e s e rv o i r f o r e a c h s e c t io n w h e r e i t c a n b e t re a t e da c c o r d i n g t o w h a t i t c o n t a in s b e f o r e b e i n g r e j e c t e d t h r o u g h t h ec o m m o n d r ai n. T h e s e b o t t o m r e se r v o ir s c a n a ls o b e u s e d as s t o c k i n g o rt e m p e r a t u r e p r e a c c l i m a t i z a t i o n r e s e r v o i r s .

Operation o f t h e system in the experimental studyF i s h r e a r i n gT h e e x p e r i m e n t s r e q u i re d t o m a i n ta i n 1 0 0 b r o o k t r o u t ( f in g e r l in g ) p e rc o n t a i n e r w i t h a p o s s i b il i t y o f 2 0 c o n t a i n e r s p e r s e c t i o n f o r a t o t a l o f6 0 0 0 s m a ll f is h f r o m h a t c h i n g t o o v e r s ix m o n t h s a f t e r h a t c h in g . T h u s ,in t h e e x p e r i m e n t a l c o n t a i n e r s a l o n e , 2 0 0 0 f is h c a n b e m a i n t a i n e d a te a c h o f th r e e d i f f e r e n t t e m p e r a t u r e s a t a g iv e n t i m e . I n a d d i t i o n af u r t h e r c a p a c i t y o f 1 0 0 0 0 s m a ll f is h f o r e a c h o f t h e b o t t o m r e s er v o ir sis p o s s i b l e .F e e d i n g p r o c e d u r eT h e f o o d u s e d w a s a s p e c ia l m i x t u r e o f d r y f o o d p e ll e ts f o r t r o u t s( M a r t i n ' s f e e d ) . T h e t r o u t s t a r t e d t o t a k e f o o d f r o m b e t w e e n 3 0 t o 5 0d a y s a f t e r h a t c h in g . T h e f o o d w a s d i s t r ib u t e d d a i ly a n d t h e fi sh l e f t t of e e d f o r 1 h ; t h e c o n t a i n e r s w e r e t h e n c l e a n s e d o f t h e r e s id u a l f o o d i no r d e r t o a v o id a c c u m u l a t i o n o f o r g a n ic m a t t e r .

V ir al c o n t a m i n a t i o nW h e n t h e f is h w e r e t o b e c o n t a m i n a t e d w i t h t h e v i ru s ( I P N ) , t h e y w e r en o t g iv e n f o o d f o r th e 4 8 h p r e c e d i n g t h e i n f e c t i o n . T h e v i ru s , w h o s et i te r h a d b e e n p r e v i o u s l y c a lc u l a t e d , w a s t h e n m i x e d w i t h t h e f o o d ,t h u s f a c i l i t a t i n g t h e t r a n s m i s s i o n b y t h e d i g e s t i v e s y s t e m .V ir al d e c o n t a m i n a t i o nI t is a b s o l u t e l y i m p e r a t i v e t o i ns u r e t h e c o m p l e t e d e s t r u c t i o n o f th ev i ru s in t h e o u t g o i n g w a t e r i n o r d e r t o a v o i d a n y p o s s i b le c o n t a m i n a t i o no f t h e n a t u r a l w a t e r s . W e k n o w t h a t a l e ve l o f 0 .1 m g l i te r -1 o f c h l o r i n e


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A l if e s u p p o r t i n g s y s t e m f o r e x p e r i m e n t i n g o n s a lm o n i d s 255f o r a p e r i o d o f 2 m i n is s u f f ic i e n t t o i n a c t i v a te t h e vi ru s I P N ( W e d e m e y e re t a l . , 1 9 7 8 ). T h u s a ll t h e w a t e r r e j e c t e d f r o m t h e c o n t a i n e r s w a s f e d t ot h e b o t t o m r e s e rv o i r w h e r e a h ig h le v el o f c h lo r i n e w a s m a i n t a i n e d( > 1 .8 m g l it e r - x) w i t h t h e a d d i t i o n o f c a l c i u m h y p o c h l o r i t e . R e g u l a rt e s ts w e r e m a d e in t h e l a b o r a t o r y t o m o n i t o r t h e p o s s i b l e p r e s e n c e o ft h e v i ru s a n d n o t r a c e o f t h e v i ru s w a s e ve r d e t e c t e d . I f i t w a s n e c e s s a r yt o u s e t h e b o t t o m r e s e r v o i r f o r s t o c k i n g f is h , it w a s t h e n p o s s i b l e t oc h a n n e l t h e c o n t a m i n a t e d w a t e r e l s e w h e r e d o w n t h e m a i n d r a in , o v e r ac a l c iu m h y p o c h l o r i t e b e d a t a c o n c e n t r a t i o n o f 2 m g l it e r- 1 f o r ar e s id u a l t i m e o f m o r e t h a n 3 0 m i n .

R E S U L T SW ater qualityS i n c e w a t e r q u a l i t y is o f c r i ti c a l i m p o r t a n c e i n a n a q u a t i c li fe s u p p o r t i n gs y s t e m t h e c h e m i c a l a n d b a c t e r i o lo g i c a l a n a l y s is o f t h e w a t e r w a su n d e r t a k e n a t d i f f e r e n t p o i n t s a lo n g t h e w a t e r p a t h w a y . T h e c h e m i c a la n a ly s is o f t h e w a t e r w a s m a d e f r o m s a m p l e s t a k e n ( 1 ) b e f o r e t h ec a r b o n f i lt e r, ( 2 ) a t t h e e n t r a n c e o f t h e t o p r e s e r v o ir s a n d ( 3 ) a t t h ee x i t s o f t h e f i s h c o n t a i n e r s . T h e r e s u l ts a r e p r e s e n t e d i n T a b l e 1 .

T h e c h e m i c a l a n a l y s is r e v e a ls a v e r y s m a ll c h a n g e i n a m m o n i a c a ln i t r o g e n ( N H a ) l e v e l w h i c h i s i n d i c a t iv e o f t h e s y s t e m e f f i c i e n c y . L i a oa n d M a y o ( 1 9 7 2 ) f o u n d t h a t a m m o n i a r e m o v a l in a f il te r w a s d e p e n d -e n t o n o r g a n ic , n u t r i e n t a n d h y d r a u l i c lo a d i ng , te m p e r a t u r e , p H ,o x y g e n c o n c e n t r a t i o n a n d r e t e n t io n t i m e . T h u s th e re s ul ts o n a m m o n i aa c c u m u l a t i o n a r e in d i c a ti v e o f a r e l a ti o n s h ip b e t w e e n t h e s e v a ri ab le s .I n a f l o w t h r o u g h s y s t e m , s u c h a s t hi s, t h e l e ve l o f a m m o n i a d o e s n o tt e n d t o a c c u m u l a t e a s s u m i n g a n a d e q u a t e r a t e o f f l o w . I n d e e d t h ev a l u e s o f N ( N H 3 ) h a v e n e v e r b e e n f o u n d t o e x c e e d 0 . 2 m g l it e r -~ .S p e e c e ( 1 9 7 3 ) w o r k e d w i t h i n f l u e n t a m m o n i a a t a c o n c e n t r a t io n o fa b o u t 0 . 5 p p m . I t is i n t e re s t in g t o c o n s i d e r t h a t , a s s u m i n g his a m m o n i ap r o d u c t i o n b y t r o u t a s a f u n c t i o n o f f is h l e n g th a n d t e m p e r a t u r e , h ea r r iv e d a t a f l o w r a t e i n li te r s p e r s e c o n d r e q u i r e d f o r 1 k g o f t r o u t a t10C o f :

Q = 0 - 0 1 3 9 l it e rs s 1 ( c l o s e d s y s t e m )C o m p a r i n g t h e a c t u a l f l o w r a te o f a p p r o x i m a t e l y 0 . 0 0 3 3 l it er s s ~( 2 0 0 m l m i n - 1) f o r e a c h o f t h e f o u r c o n t a i n e r s a t e a c h s t o r e y i t s h o u l d


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256 D . L a r r i v d e , J . L a p i e r r e , L . B e r t h i a u m eT A B L E 1

Analysis of Water Taken at Different Points Along Water Path-way (t = 15C) (in mg liter -1)

1 a 2 b 3 c

pH 6.5 6.3 6.8C1- (chloride) 15 15 15Alkalinity (CaCO3) 20 20 20N(NO;) (nitrate) 0.12 0.12 0.10N(NHa) ammonia NS NS 0.2N(NO~) nitrite NS NS NSCO2 40 16 34C12 (chlorine) NS NS NSFe 3+ NS NS NSCu 2+ NS NS NSa Water sample before its filtration in the activated carbon filter.b Water sample from the top reservoir.c Water sample from the fish container exit.NS, Not significant.

be possible to convert each level into a closed-circuit system with thesame conditions of carrying capacity as used by Speece, and with anacceptable N(NH3) level.

The levels of chlorine which appear to be below the analytical detec-tion point have on rare occasions exceeded 0.5 ppm in the incomingwater but have remained at a very low level (lower than 0.05 ppm) afterpassing through the carbon filter. Another element which was especiallymon ito red in the wa ter was copper, since the pipe system bringing thewater was made of copper. As indicated in the Table, no significantdetectable level was ever found. If the system was to be converted intoa closed-system it would be particularly important to monitor thiselement.

The pH follows a normal evolution, being slightly more acid afterpassing through the carbon filter and slightly more basic after beingused by the animals.

The COs level at different points of the water flow also reveals apredictable behavior. It enters t he system at the level of 40 mg liter ~.


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A l ife support ing system fo r expe riment ing on salmonids 257After bubbling air through (top reservoirs) the COz level goes down to16 mg liter-a and goes up again to 34 mg liter a after the water has beenused b y the animals. Bacteriological analysis was made from: A, samplestake n before the water enters the carbon filter; B, samples of the 12 hresidual water in the carbon filter; and C, samples of the top reservoirwater. There is no significant accumulation of bacteria in samples Aand C. If the water is left stagnant for 12 h in the carbon filter, bacteriado accumulate up to a dilution of 1:10000. It shows that the flowthrou gh system does not favor the accum ulation of bacteria. But theresults are also indicative of the efficiency of the carbon filter as anorganic material adsorbant on which the bacteria can feed.G r o w t hGrowt h is one of the parameters which can be used to stu dy the effectsof envi ronmenta l changes (physico-chemical and biological) on the fish.After 90 days at 5C the fish fry were distributed in equal numbers incontainers at three different temperatures (5C, 10C and 15C). Three

T A B L E 2Growth of Brook Trout Fry (Weight and Length) at Three Different Temperaturesin the Experimental System (Average of 50 Measurements)

Day s f ro m Temperaturethe s tarto f t he 5C 10C 15C

experim en tWeight Len gth Weight Len gth Weight Le ngth

{g) ( cm ) (g ) ( em ) (g ) ( em )0 a 0.03 1.5 0.03 1.5 0-03 1-53 0.04 1.6 0.06 2.0 O. 10 2.07 0-07 1.8 0.06 2.0 0.11 2.1

13 0-05 1"7 0.08 1.8 0.21 2.420 0.05 1.9 0.10 1.9 0.22 2.741 0.13 2.3 0.52 3.1 1.24 4.577 0.46 3.2 1.00 3.9 4.39 6.1

a 90 days from fertilization (beginning of feeding).


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258 D. Larrivde, J . Lapierre, L. BerthiaumeTABLE 3

Growth Rates (Wi -- Wo/Ti - - To or Li - - L o / T i - - T o , where W= Weight in g,L = Length in cm and T--- Time in Days, and the Subscripts i and 0 IndicateRespectively the End and the Beginning of the Experiment)

Tem p era t ure ( C) G row t h ra te ( g day - 1 ) G row t h ra te ( cm day - 1 )5 0.006 0-02

10 0.013 0.0315 0.06 0.06

hundred fry in each container were then grown at similar conditions offeeding (daily) and photope riod (12:12). At intervals, approxi mately50 individuals were sampled from each container, measured (totallength) and weighed (wet weight). Table 2 represents the average weightand length at these temperatures. As the results indicate, at the end ofthe experimental period the fish at 15C weighs on average 3.93 g morethan the fish raised at 50C and 3-39 g more than the fish raised at 10C.Correspondin gly, the fish raised at 15C measures 2.90 cm more thanthe fish raised at 5C and 2.20 cm more th an the fish raised at 10C.If we now compare the growth rates at these three temperatures weobtain the data shown in Table 3.

From this it can be observed that in weight the fish raised at 10Cgrows 2.17 times faster than the fish raised at 5C but 4.62 times slowerthan the fish raised at 15C. Likewise the fish raised at 10C grows inlength 1.5 times faster than the fish raised at 5C but twice as slow asthe fish raised at 150C. It is appreciated that the metabolic activitieswhich underlie the growth processes do not follow a linear relationshipwith temperature. Moreover, the growth curves at these temperaturesare a reliable indicator of the stability of the system.Mortal i tyIn an experiment using 1800 fry, the mortality was monitored. Therewas not observed significant differences in animal death between thepopulations at 5C, 10C and 15C; mortality was lower than 10%. Thisis particularly interesting since it underlies the quality of the systemconditions for raising fish. Evidently it also insures more possibilities


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A l if e s u p p o r t in g s y s t e m f o r e x p e r i m e n t i n g o n s a l m o n i d s 259for testing clearly the effects of environmental changes under thesetemperatures.Vira l in f ec t io n experimentThis life supporting system was designed mainly to study the variableswhich affect the viral infection (IPN) of the brook trout. Temperature,water quality, physiolog{cal age, route of infection are all aspects whichare being tested. The experimental protocol which has been developed,using this sytem, allows significant numbers of fry to be infected withIPN. The behavior and structural damage caused by IPN infection isbeing studied.

DISCUSSIONProblems associated with salmonid life supporting systems usually relateto variations in critical environmental parameters such as temperature,oxygen tension, water quality, accumulation of wastes and mechanicalinjury due to various causes. In order to study a specific viral pathology(IPN) in the brook trout we had to minimize any variation in theculture conditions which would interfere with the results and makedifficult their interpreation. We thus developed a system at low costwhich offers us high reliability and flexibility, as an evaluation ofcertain of its characteristics seems to indicate. In terms of constancy inthe operation, sufficient carrying capacity to permit statistical inter-pret ation and optimization capabilities for self-cleaning and preventionfrom pathogens, this system offers many opportunities for carryingout critical experiments dealing with different variables such as foodbudget, specific pathogens or behavioral traits. Blaxter (1970) hassuggested that sensory deprivation may be a common phenomenon intank-raised fish larvae. We know that after completion of larval develop-ment mortalities usually drop drastically. The present system whichcarries a low rate of mortalities seems to point to a favorable environ-ment for raising the brook trout and offers good opportunities forbehavioral studies. By separating the functions of aeration and coolingfrom the rearing space, and by reducing the variations in the water flow(gravity supply) and in other parameters such as temperature and


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260 D. Larrivde, J . Lapierre, L. Berthiaumeo x y g e n a t i o n , w e t h i n k w e h a v e a v o i d e d u n n e c e s s a r y s tr e ss o n t h ea n i m a l s , w h i c h u s u a l l y m a k e s d i f f i c u l t t h e i n t e r p r e t a t i o n o f t h e r e s u lt s .W i th t h is s y s t e m w e h a v e o p e n e d u p i n t e r e s t in g p o s s i b il i ti e s fo r t h es t u d y o f c r it ic a l d e v e l o p m e n t a l e v e n t s in t h e li fe o f t h e f is h , s u c h a s t h ei m m e d i a t e p o s t h a t c h i n g p e r i o d w h e r e t h e m o r t a l i t y i s u s u a l ly h ig h .

A t h i g h e r c o s t , se v e ra l i m p r o v e m e n t s c a n b e a d d e d t o t h is s y s t e ms u c h a s a n a u t o m a t i c t e m p e r a t u r e c o n t r o l a n d a n a u t o m a t i c f is h f e e d e r.P r e s e n t ly t h e s y s t e m o f f e rs n u m e r o u s o p p o r t u n i t i e s t o s tu d y s a lm o n i d sf r o m f e r t i li z a t i o n t o a d u l t h o o d . M a t e r ia l s t o t r e a t t h e eg g s a n d th el a rv a e c a n b e i n j e c t e d d i r e c t l y i n t h e t o p r e s e r v o ir s a n d d i s t r i b u t e du n i f o r m l y t o a l l fi sh . T h e s y s t e m c a n a ls o b e e a si ly c o n v e r t e d i n t o a ne g g i n c u b a t o r a n d a n h a t c h e r y . O n e c a n a l s o u s e s m a l l e r o r l ar g e r c o n -t a in e r s a d a p t e d t o t h e n e e d s o f t h e e x p e r i m e n t s . T h e s y s t e m ca n e a s il yb e c o n v e r t e d i n t o a c l o s e d s y s t e m b e c a u s e o f t h e re l at iv e i m p o r t a n c e o ft h e r e s i d u a l v o l u m e ( > 1 5 0 0 l i te r s ) o v e r t h e f l o w r a t e ( 2 0 0 m l m i n- 1 ).

A C K N O W L E D G E M E N T SW e w a n t t o o f f e r o u r g r a t e fu l t h a n k s t o M r M a r c e l V i l le n e u v e w h o h a sc o l l a b o r a t e d in t h e c o n s t r u c t i o n o f t h e l i f e s u p p o r t i n g s y s t e m a n d t oM r S e rg e G o n t h i e r a n d Y v a n T u r g e o n ( D e p a r t m e n t o f R e c r e a t i o n , F is ha n d G a m e s , Q u 6 b e c ) w h o k i n d l y p r o v i d e d t h e h v i n g m a t e r i a l .

R E F E R E N C E S A N D B I B L I O G R A P H YAlderdice, D. F. & Velsen, F. P. J. (1968 ). De sign of a control led-environment

incu bato r for small marine f ish eggs. J. Fish . Res . Bd. Can. , 2 5 , 5 8 5 .Alderdice, D. F., B ret t , J . R. & Sutherland, D. B. (1966 ). De sign of small holdingtank for f ish. J. Fish . Res . Bd. Can. , 23, 1447.Blaxter, J. H . S. (19 70 ). Sensory deprivation an d senso ry inp ut in rearing experi-men t s . Helgol~nder w iss . Meeresunters , 20 , 642 .Bret t , J . R., Sutherland, D. B. & Heri tage, G. D. (197 1). An environmental con trolt ank fo r t he synchronous s tudy o f g rowth and m etabo li sm o f young salmon .

J . F i sh . Res. Bd . C an . Techn . Rep . , 283, 1 .Burrows, R. E. & Chenoweth, H. H. (1970). The rectangular circulat ing rearingpond . Progres. Fish Calturis t , 32, 67 .


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262 D. Larrivde, J. Lapierre, L. BerthiaumeSpeece, R. E. (1973). Trout metabolism characteristics and the rational design of

nitrification facilities for water reuse in hatcheries. Transact ions o f the Am er icanFisher ies So c ie ty , 102, 223.Spotte, S. (1979). Fish and inver tebrate culture . Water man agem ent in c losedsys tems , Wiley-Interscience, New York.

Wales, J. H. & Evins, D. (1937). Sestonosis, a gil l irritation in trout. CaliforniaF i s h a n d G a m e , 23, 2.Wedemeyer, G. A., Nelson, N. C. & Smith, C. A. (1978). Survival of the salmonidviruses infectious hematopoietic necrosis (IHNV) and infectious pancreaticnecrosis (IPNV) in ozonated chlorinated and untreated waters. J. Fish. Res. Bd.Can., 35,875.

Westers, H. (1970). Carrying capacity of salmonid hatcheries.Progres. F ish Cu lturist,32, 43.Willoughby, H. (1968). A method for calculating carrying capacities of hatcherytrough and ponds. Progres . Fish O dtur is t , 30, 173.Zillioux, E. J. & Lackie, N. F. (1970). Advances in the continuous culture of plank-tonic copepods. Helgoli inder wiss. M eeresu nters , 20, 325.

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Larrivee 1983 Aquacultural-Engineering

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