kepiting (2)
TRANSCRIPT
-
7/26/2019 kepiting (2)
1/15
t u r t i i e g - e p u e j s o Q
: ! ! S H 3 G N V l d
ci J ( - '' ' S ' W W l A
( m z a ) y n A
Aqu acultu re Research, 2007, 38, 1539-1553 doi:10,llll/j.l365-2 109.2007.01814.x
Improved techniques for rearing mud crab Scylla
paramamosain (Estam pador 1949) larv ae
Truong Trong Nghia1, Mathieu Wille2, Tran Cong B inh \ H oang Ph uo c Th anh1, Nguyen Van Dan h1 &
Patrick Sorgeloos2
'College of Aq uacu lture an d Fisheries, Ca nTho University, Can Th o City, Vietnam
labo rato ry of Aquaculture &Art emia Reference Center, Gh ent University, Ghent, Be lgium
Correspondence: T Trong Nghia, College of Aquaculture and Fisheries, Can Tho University, 3rd February avenue, Campus II. Can Tho
City,Vietnam. E-mail: [email protected]
Abst rac t
A se r ie s o f r ea r in g t r i a l s in sma l l 1 L co n es an d la rg e
tan k s o f 3 0 -1 0 0 L w ere ca r r ied o u t to d ev elo p o p t i
m a l r e a r i n g t e c h n i q u e s f or m u d c r ab {Scylla param a-
mosain)l a rv ae . Us in g wa te r ex ch an g e (d i sco n t in u o u s
p a r t ia l w a te r r e n e w a l o r c o n ti n u o u s tr e a tm e n t
th ro u g h b io f i l t r a t io n ) an d mic ro -a lg ae (Chlorella o r
Chaetoceros) su p p lemen ta t io n (d a ily su p p lemen ta t io n
a t 0 . 1 -0 . 2 m i l l io n c e ll s m L - 1 o r m a i n t e n a n c e a t
1 -2 mi l l io n s ce l ls m L- 1 ) , s ix d i f fe ren t ty p es o f
r e a r i n g s y s t e m s w e r e t r i e d . T h e c o m b i n a t i o n o f a
g reen -w a te r b a tch sy s tem fo r ea r ly s tag es an d a r ec i r
c u l a t i n g s y s t e m w i t h m i c r o -a l g a e s u p p l e m e n t a t io n
fo r l a te r s tag es r e su l ted in th e b e s t o v e ra l l p e r fo r
m an ce o f th e c rab la rv ae . No c lea r e f fect s o f c rab
s t o c k i n g d e n s i ty ( 5 0 - 2 0 0 l a r v a e L " ^ a n d r o t if e r
(3 0 -6 0 ro t i f e rs mL ~ 1) an d A rt em ia d en s i ty (1 0 -
2 0 L- 1 ) w e re o b se rv ed . A s to ck in g d e n s i ty o f
1 0 0 - 1 5 0 z o e a 1 ( Z 1 ) L ~ \ c o m b i n e d w i t h r o t if e r
o f 3 0 -4 5 mL ~1 fo r ea rly s tag es an d A rt em ia feeding
a t 1 0 - 1 5 n a u p l i i m L - 1 f o r Z 3 - Z 5 s e em e d t o p ro d u c e
t h e b e s t p e r f o r m a n c e o f S. paramamosain la rvae . Op
t ima l r a t io n s fo r c rab la rv ae sh o u ld , h o wev e r , b e ad
ju s te d d ep en d in g o n th e sp ec ie s, la rv a l st ag e , la rv a l
s ta tu s , p rey size , r e a r in g sy s tem a n d tech n iq u es . Ap ra c ti c a l fe ed in g sc h ed u le co u ld b e to in c re a se liv e
fo o d d en s i ty f ro m 3 0 to 4 5 ro t i fe r s mL - 1 f ro m Z1 to
Z 2 a n d i n c r e a s e t h e n u m b e r o fA rt em ia n a u pl ii m L - 1
f ro m 1 0 to 1 5 f ro m Z3 to Z5. Bac te r ia l d i sea se r ema in s
o n e o f t h e k e y f a c to r s u n d e r l y i n g t h e h i g h m o r t a li t yin th e zo ea s tag es . Fu r th e r r e sea rch to d ev e lo p sa fe
p ro p h y la c ti c tr e a tm e n ts is t h e re fo re w a rr a n te d . C om
b in ed w it h p ro p e r live fo o d e n r ic h m e n t te ch n iq u es ,
ap p l ica t io n o f th e se f in d in g s h a s su s ta in ed a su rv iv a l
ra te f ro m Z1 to c rab 1 -2 s tag es in la rg e rea r in g tan k s
o f 1 0 -1 5 % (m ax im u m 3 0%) .
Keywords: Scylla paramamosain, r e a r i n g t e c h n i
q u es , wa te r ex ch an g e , mic ro -a lg ae , l a rv a l d en s i ty ,
l ife food density , prop hyla xis
Introduction
Aq u acu l tu re o f m u d c rab s . Scylla sp p ., co n t r ib u te s a
la rg e p ro p o r t io n to th e wo r ld p ro d u c t io n o f th e g en u s
(FAO1999). Moreover , m ud crabs rep rese nt a valuable
co m p o n en t o f sma l l - sca led co as ta l f i sh e rie s in man y
co u n t r ie s in tro p ica l an d su b t ro p ica l As ia , fo r wh ich
th e re h a s b een a g en e ra l t r en d o f in c rea sed ex p lo i ta
t ion in rece nt yea rs (Angeli 1992; Keen an 1999 a). In
Vie tn am, th e mu d c rab Scylla paramamosain is the
s e c o n d m o s t i m p o r t a n t m a r i n e s p e c ie s n e x t t o
sh r imp , b e in g cu l tu red wid e ly in th e co as ta l a rea .
Ho weve r , mu d c rab fa rmin g cu r ren t ly r e l ie s en t i r e ly
o n th e w i ld fo r seed s to ck an d th e m a in o b s tac le fo r
ex p an s io n i s th e u n av a i lab i l i ty o f h a tch e ry - rea red
seed (Lio n g 1 9 9 2 ; Ra t tan ach o te & Dan g wa tan ak u l
1992; Keenan 1999a; Shelley & Field 1999; Mann,Asakawa, Pizzuto , Keenan & Brock 2001; Xuan
2001).
Rear in g tech n iq u es , d i sea se an d n u t r i t io n a re th e
th ree ma in a rea s o f r e sea rch th a t h av e su p p o r ted
c o m m e r c i a l p r o d u c ti o n o f m a r i n e f is h a n d c r u s t a
cea n larv ae (Sorgeloos & Lger 1992). The se thr ee as
p e c ts a re to a la rg e e x te n t in te rc o n n e c te d a n d
developing hatc hery tech niqu es for a new species is
n o t p o ssib le u n le s s a l l th e a rea s a re ad d re ssed . Th e
2007 The AuthorsJourna l Compilation 2007 Blackwell Publishing Ltd 1S39
mailto:[email protected]:[email protected] -
7/26/2019 kepiting (2)
2/15
Improved rearing tech niques for mud crab larvae T T Nghiaet al. Aquaculture Research, 2007, 3 8, 1539-1553
des ign o f rea r ing sys tems covers more than pure ly
techn ica l aspec ts . Snb-op t imal rea r ing condi t ions
(e.g. physical stress, lack of oxygen or sub-optimalwate r qua l i ty ) a f fec t la rva l hea l th and can cause
mass m or ta l i ty due to d isease ou tbreaks . S imilar ly ,
system design influences (live) food quality and its
ava i lab i l ity to th e p reda tor la rvae .
There has bee n a g rea t dea l o f p rogress in mar ine
la rva l rea r ing technology s ince i t s beg inn ing in the
1960s (Shelbourne 1964; Howell, Day, Ellis & Baynes
1998) . Many of these techn ica l improvem ents deve l
oped over the p as t decades cou ld be app l ied fo r mud
crab wi th some modif ica t ions . An overv iew of the
rear ing sys tems cur re n t ly app l ied fo r la rv icu l tu re o f
mud c rabs was p re sen ted by Davis (2003) . A l though
knowledge has been ob ta ined f rom these sys tems,there is a need to fu r th er op t im ize rea r ing techn iques
in o rder to maximize la rva l su rv iva l and qua l i ty .
Fur thermore , techn iques shou ld be adap ted fo r each
Scylla species (Keenan, D avie & M ann 1998; Keena n
1999b) in re la t ion to loca l condi t ions ( seawate r
s o u rc e , s t a tu s o f h a t c h e r y m a n a g e m e n t , l o ca l
resources) . The a im of th is resea rch i s to adap t the
ex is t ing rea r in g sys tems fo r la rv icu l tu re to mud c rab
species (S. pa ra m am osa in be ing th e tes t case ) and to
improve o th er techn iq ues in o rd er to maximize la rval
surv iva l and qua li ty .
Materials and methods
Source o f larvae
Gravid c rabs were bought f rom loca l marke ts and
t ranspor ted to the ha tchery . Before s tock ing in the
ha tchery , the c rabs were sub jec ted to a ba th o f
1 0 0 p L L - 1 o f a 4 0 % f o r m a l i n s o l u t io n f o r l h . T h e
crabs were s tocked ind iv idua l ly in 100 L com par t
ments o f a roofed 2 x 2 x 0.5 m cem ent tank ,
equipped with a biofilter . Rearing water of
30 1 g L 1 salinity wa s diluted from b rine (90
110 g L " x) w ith tap wa ter an d c hlor inated before use.
Ambien t tempera tu re f luc tua ted s l igh t ly a round
28 C. Every crab w as fed a daily ra tion of 10-15 g offresh m arin e squid, bivalve or shrim p m eat alternately.
Af te r 3 -5 days o f acc l imat ion , un i la te ra l eyes ta lk
ab la t ion was app l ied to induce spawning . Af te r
spawning , ber r ied c rabs were aga in sub jec ted to a
100 pL L _ 1 fo rm al in ba th fo r 1 h and t ransfe r red to a
70 L p las t ic tank co nne c ted to a b io f i lte r fo r egg incu
ba ti o n . D ai ly m a n a g e m e n t c o n s is te d o f si p h o n in g o u t
w a s t e m a t e r ia l s a n d s h e d d e d e g g s f ro m t h e t a n k b o t
tom and co n tro l l ing the te m pe ra tu re (30 C) , sa l in i ty
(30 g L -1 ) and am m onia and n i t r i te leve ls . Every
o the r day , the c rabs were p laced in a 50 pL L- 1 fo r
m al in ba th fo r 1 h to reduc e o r p rev en t in fes ta t ion o ft h e e g g s w i t h f u n g i a n d b a c t e ri a . D u r i n g e g g i n c u b a
tion, the crab s were no t fed.
One to two days before ha tch ing , the ber r ied
female was m oved to a 500 L f ib reg lass tank . When
the ha tch ing process was comple ted , la rvae were
se lec ted based on the i r pho to tac t ic behav iour . Aera
t i o n i n t h e h a t c h i n g t a n k w a s t u r n e d o ff f o r se v e ra l
m i n u t e s a n d t h e a c t iv e l ar v a e s w i m m i n g u p t o t h e
sur face w ere co l lec ted by gen t le scooping .
T h e l a r v a e w e r e t h e n t r a n s f e r r e d t o t h e r e a r i n g
conta iners . Acc l imat ion was per fo rmed by p lac ing
the la rvae in a 50 L p las t ic mes h buc ke t and s lowly
r i n s i n g t h e m w i t h w a t e r f ro m t h e l a r v a l r e a r i n g c o n t a i n e r s f o r 2 0 - 3 0 m i n b e fo r e r e le a se .
Food and feeding
M icro a lg ae cu ltur e
S t a r t in g c u l t u r e s o f t h e m i c r o - a l g a e Chaetoce ros calci-
trans a n d Chlorella vulgaris w e r e m a i n t a i n e d i n d o o r s
w i th Walne so lu t ion in seaw ate r o f 30 g L 1 a t 25 C.
Large-sca le p roduc t ion was per fo rmed indoors in
5 0 0 L t a n k s u n d e r a t r a n s p a r e n t r o of . A h a e m o c y t -
om ete r w as used to cou nt m icro-a lga l densi t ies .
R ot if er c u lt u re an d e nr ic hm en t
T h e s a m e B ra ch io nu s p li ca ti li s L -s t ra in w i th a lo r ica
l e n g t h a n d w i d t h o f 1 6 4 2 2 a n d 1 2 0 22 pm, re
spectively, was used in all the experiments. Rotifers
were cu l tu red indoors in 100 L f ib reg lass tank s oper
a ted in a ba tch mode , fo l lowing the p rocedure de
scribed in Sorgeloos an d Lavens (1996). Rotifers were
in i t ia l ly g rown on bakers yeas t , bu t la te r on fed
Cul tu re Se lco ' ( INVE Aquacu l tu re , Dendermonde
Belg ium) before feed ing to th e la rvae . Tempera tu re
a n d s a l i n i t y w e r e c o n t r o ll e d a t 2 5 C a n d 2 5 g L _1
respec tive ly . They w ere harves ted th rou gh a 60 pm
screen and r insed thoroughly .Rot ife rs w ere enr iched w i th m icro-a lgae o r a r t i fi
c ia l enr ic hm ent media before be ing fed to the c rab
la rvae . Enr ichment w i th Chlorella was per fo rmed a t
a de nsi ty of 5 x IO6 cells mL ~ 1 for 3 h (D hert 1996).
Rot i fe rs were a lso enr iched w i th Dry Imm une Se lcoa
(DIS ", INVE Aqu aculture), usin g tw o sep arate doses
of 0 .05 g L 1 a t a 3 -h in te rva l . Enr ichm ent was per
fo rmed a t a d ens i ty o f 5 00 ro t ife rs mL 1 .T h e w a t e r
in the enr ichment vesse l was s lowly hea ted to
1540 2007 The Authors
Jour nal Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Resea rch, 38, 1539-1553
-
7/26/2019 kepiting (2)
3/15
Aquaculture Research, 2007, 38, 1539-1553 Improved rearing techn iques for mud crab larvae T T Nghia et al.
Tab le 1 Overview of larval rearing systems applied in this study based on the me thod of wate r exchange and m icro-algae
supplementation
Water e xc han ge
Algae s upple m e nta t ion
Dis c ont inuous m anua l
partial water renew al
Cont inuous wate r
tr e a tm e nt thr ough the
u se o f a biofilter
No mi cro -al ga e su pp le m en te d (ind oor s) Clear-Batch system Clear-Recirc system
Micro-algae suppleme nted at low levels to provide
extra food for live preys (Indoors or outdoors)
Algae-Batch system Algae-Recirc system
Micro-algae supplemented at a high concentration
and self-sustainable under natural sunlight as an
extra food for live pre y an d wate r conditioning (outdoors)
Green-Batch system Green-Recirc system
(Combination of Green-Batch and
Algae-Recirc system at early and late
larval stages respectively)
2 9 -3 0 C to av o id ex p o s in g th e ro t if e r s to th e rm a l
s h o c k w h e n t h e y w e r e a d d e d t o t h e l a r v a l r e a ri n g
tanks . Before being fed to the larvae , enrich ed ro tifers
were r in sed an d re - su sp en d ed in c lean seawa te r a t
th e same temp era tu re a s th e c rab - rea r in g tan k s.
A rt em ia cu lt ur e a nd en ri ch m en t
A rt em ia n au p l i i (Vin h Ch au s t r a in ) w e re h a tch ed a s
d esc r ib ed b y Van S tap p en (19 96 ). B o th n ew ly h a tch ed
o r e n r i ch e d A rt em ia n au p l i i we re u se d in th e ex p e r i
men ts o f th i s s tu d y . A rt em ia w e r e e n r i c h e d w i t h
Chaetocerosin th e same m ic ro -a lg a l d en s i ty a s fo r ro
t i f e r en r ich m en t . Th e n au p l i i we re a l so en r ich ed wi th
DIS (using two s epa rate do ses of 0 .3 g mL 1 a t a 6-hin terv a l) . W a te r t em p era tu re an d sa l in i ty we re ma in
ta in ed a t 3 0 C an d 3 0 g L ~ \ r e sp ec tiv ely , d u r in g
A rt em ia e n r i c h m e n t . T h e d e n s i t y o f A rt em ia d u r in g
en r ich m en t was 2 0 0 m L -1 . Befo re f eed in g to th e
c rab la rv ae , th e A rt em ia we re r in se d w i th d i s in fec ted
s e a w a t e r a n d s u s p e n d e d a t a k n o w n d e n s i t y i n
seawater .
Feed ing
Rotifers were fed to the crab larvae from 0 to 6 days
a f te r h a tch (DAH 0 -6 ) [ ro u g h ly co r re sp o n d in g to
zoea 1 (Zl)-Z2 s tages] . Newly hatched A rt em ia o rA rt em ia meta-naupli i were offered from DAH 6 (Z3
stage) onwards. Rotifers and A rt em ia we re ad d ed
d a il y a t 3 0 - 4 5 a n d 5 - 1 0 m L - 1 t o t h e re a r in g t a n k
respec tively (e xpe rim ents 1, 2, 3, 4, 7 and 8). For
experiments 5 and 6 , l ive feed were fed a t the
req u i red p rey d en s i t i e s b a sed o n th e p lan n ed
t rea tmen ts . W h en ev e r th e c rab la rv ae we re f ed en
r iched l ive feed, a lgae- or DIS -enriched l ive feed
were u sed o n a l t e rn a te d ay s.
Larval rearing exp erim ents: objectives and experimental des ign
In ex p e r im en ts 1 ,2 an d 3 , th e e f fec t o f d i f fe ren t wa te r
ex ch an g e sch emes an d th e ad d i t io n o f mic ro -a lg ae
o n la rv a l su rv iv a l a n d d ev e lo p men t we re ev a lu a ted .
I n e x p e r i m e n t s 4 - 8 , o t h e r c u l t u r e a s p e c t s s u c h a s
Z1 s tocking density , l ive food den sity an d th e effect of
d i ffe ren t p ro p h y lac t ic t r ea tm en ts we re in v est iga ted .
T h e w a t e r q u a li t y m a n a g e m e n t s c h e m e s t e s te d i n e x
p e r im e n ts 1 - 3 a re su m m a ri z e d in Tab le 1. A n ov er
v i e w o f t h e e x p e r i m e n t a l d e s i g n a n d c u l t u r e
co n d i t io n s o f a l l th e e x p e r im en ts i s p re sen ted in
Tab le 2 . Th e sm a l l - sca le e x p e r im en ts (1 -3 0 L) we re
c a r r i e d o u t i n a t e m p e r a t u r e - c o n t r o l l e d r o o m
(2 8 -3 0 C) . Th e ex p e r im en ts in 1 0 0 L tan k s we re
pe rf o rm ed o u td o o rs a t a m b ie n t te m p e ra tu re (2 7 -
31 C). The source and the d is infection procedure of
th e seaw a te r fo r l a rv a l r ea r in g were s im i la r to th o se
u sed fo r b ro o d s to ck rea r in g . Fo rm a l in a t a co n c en t ra
t io n o f 2 0 p L L ~ 1 was ap p l ied ev e ry o th e r d ay a s a
pr o p h y la ct ic t r e a tm e n t i n e x p e r im e n ts 1 -6 .
E xp er im en t 1
Larv a l su rv iv a l an d g ro wth in a c lea r wa te r sy s tem
w i th d a i ly p a r t i a l w a te r ex ch an g e (Clea r -Ba tch ) was
co mp ared wi th th o se in a c lea r wa te r r ec i rcu la t in g
system (Clear-Recirc) . In the f irs t rear ing system,3 0 -5 0 % o f th e w a te r was rep laced d a ily. In th e r ec i r
cu la t in g sy s tem, a l l r e a r in g tan k s we re co n n ec ted to
a centra l b iofil ter . W ater wa s recirc ula ted a t a ra te of
ap p ro x ima te ly 10 0 % o f th e t an k v o lu m e ev e ry 3 - 4 h .
L iv e fo o d an d c rab la rv ae we re r e ta in ed in th e r ea r in g
t a n k s w i t h b y a m e s h s c r e e n o f 7 0 a n d 3 0 0 p m d u r
in g th e ro t i f e r an d A rt em ia feeding s tage respectively .
La rg e r mesh sc reen s (2 5 0 an d 5 0 0 -1 0 0 0 p m fo r ro ti
f e r an d A rt em ia s tage respectively) and higher f low
2007 The AuthorsJourna l Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re R esea rch, 38, 1539-1553 1541
-
7/26/2019 kepiting (2)
4/15
Table
2
Overview
ofthe
experimentalconditions
and
waterquality
parameters
(mean
standard
deviation)in
experiments
1-8
Improved rearing techniques for mud crab larvae T T Nghia et al. Aqu acultu re Rese arch. 2007, 38, 1539-1553
T - o > - c o m m o o ) i n o 5 c o c or q q q c o r - r n c o w c ' j q - H - H - H - H - H - H - H - H - H - f l - H - H- j r T f O N O i f j c o c o n ^ t o
T - T - O T - i n T r i - L n T r ^ c o od d d d d d d d
^ r r ^ T f o D O o r ^ c D C M c o c o i nco in
oooot-1 o
-H -H -H -H +1 -Ht) (O (\J N CM T r-co o o o i no o o o ^
(O ( ^ " d o d ot -H -H -H +1os cotoinoo r-q
o o o o
O O UJ O O
.
0) *. a)JS E
0J io E CvJ
a. S o 's
0 3qc
4 1
ca
-
7/26/2019 kepiting (2)
5/15
A q ua cu lt ur e R es ea rc h, 2 007 , 3 8, 15 39 -1 55 3 I mp ro ve d r ea ri ng t e ch n i q ue s f or m u d c ra b l ar va e T T N g h i a et al.
r a t e s w e r e u s e d u p o n d a il y f lu s h i ng o u t o f u n e a t e n
live food and w aste .
E xper im en t 2
A C l e ar -R e c ir c s y s t e m w a s c o m p a r e d w i t h t w o
sy s tems wh e re mic ro -a lg ae we re ad ded . Rea r in g co n
d i t io n s fo r th e Clea r-Rec i rc sy s tem were s im i la r to
th o se d e sc r ib ed in ex p e r im en t 1. In th e Alg ae-Rec i rc
sy s tem, mic ro -a lg ae w e re ad d ed d a ily to th e r ec i rcu
la t in g sy s tem a t a lo w co n cen t ra t io n ran g in g f ro m 0 .1
to 0 .2 mill ion cells mL ~ \ Th e o p e ra t io n o f th e r ea r
in g tan k s was s im i la r to th e Clea r -Rec i rc t r ea tmen t .
In th e Green -Ba tch t r ea tm en t , a c la s s ica l g reen -
w a te r sy stem, mic ro -a lg ae co n cen t ra t io n s in th e cu l
tu re t an k s we re k ep t a t a t en fo ld h ig h e r l ev e l o f
1 - 2 m i l l io n c e ll s m L - 1 . I n t h i s s y st em , t h e c u l t u r e
tan k s w e re in i t i a l ly o n ly f i ll ed to 5 0 % o f th e i r c ap a
c i ty an d g rad u a l ly in c rea sed to 1 0 0 % b y th e en d o f
th e Z2 s tag e b y ad d in g wa te r an d a lg ae d a i ly . La te r
o n , 1 0 -3 0 % o f th e r ea r in g wa te r was rep laced d a i ly
by c le a n s e aw a te r a n d /o r al g ae , d ep en d in g o n th e
d e n s i t y o f m i c r o - a l g a e r e m a i n i n g i n t h e r e a r i n g
tan k s . Up o n wa te r ex ch an g e , u n ea ten l iv e fo o d was
a l so f lu sh ed o u t th ro u g h a mesh sc reen (mesh s ize s
a s d e sc r ib ed in ex p e r imen t 1 ) . Th e same amo u n t o f
l iv e fo o d (3 0 -4 5 ro t i f e rs mL 1 an d 5 -1 0 A rt em ia
n au p l i i mL ~L) was fed in a l l th e t r ea tmen ts . I n th e
sy s tems u s in g a lg ae , Chlorella was u sed fo r Z1 -Z3
s tag es (wh ich i s u n su i tab le a s a fo o d so u rce fo rA rtem ia ); f ro m Z4 o n ward s . Chlorella was g rad u a l ly
r e p l ac e d w i t h Chaetoceros.
E xp eri m en t 3
In th i s ex p e r imen t , a G reen -Ba tch an d a Green-Rec irc
sy s tem were se t u p in o rd e r to fu r th e r ev a lu a te th e
ap p l ica t io n o f mic ro -a lg ae o n th e p e r fo rman ce o f
c rab la rv ae . Th e f ir s t r e a r in g sy s tem w as a b a tch sy s
t e m w i t h a d d i t i o n o f h i g h c o n c e n t r a t io n s o f a l g a e a s
d e s c r i b e d i n e x p e r i m e n t 2 . T h e s e c o n d s y s t em c o n
s i s ted o f a co mb in a t io n o f th e Green -Ba tch sy s tem
fo r ea r ly c rab s tag es (Z1 -Z2 ) an d a Alg ae -Rec irc sy s
tem fo r l a te r s tag es (Z3 o n ward s) .
E xp eri m en ts 4 6
In th e s e ex p e r im en ts , th e e f fec t o f Z1 s to ck in g d en s i ty
(5 0 , 1 0 0 , 1 5 0 an d 2 0 0 L ~ \ expe rim ent 4), ro t ifer
f e e d in g d e n s i t ie s a t 3 0, 4 5 a n d 6 0 m L - 1 f o r Z 1- Z 2
(ex p e r imen t 5 ) an d A rt em ia densities at 10, 15 and
2 0 mL 1 fo r Z3 o n w ard s ( ex p e r imen t 6 ) was ev a lu
a t ed . T h e s e e x p e r i m e n t s w e r e r u n i n a G r e en - B a tc h
(ex p e r imen t 4 ) o r a Clea r -Rec i rc sy s tem (ex p e r imen ts
5 and 6) as de scrib ed above.
E xp er im en t 7
In ex p e r imen t 7, th e e f fec t o f p ro p h y lac t ic ch emica l s
o n th e su rv iv a l o f th e l a rv ae was in v es t ig a ted . Th ree
t rea tmen ts , co n s i s t in g o f a co n t ro l (n o ch emica l s
u sed ), d a i ly ad d i t io n o f fo rma l in a t 2 0 p L L ~ 1 an d d a i
ly ad d i t io n o f Ox y te t racy c l in e a t 1 0 m g L \ w e r e r u n
in 1 L p la s t ic co n es . A l l co n es we re p laced in a wa te r
b a th in o rd e r t o m a in t a in t h e r e a r in g te m p e r a tu re a t
30 C. Water w as r epla ced a lm ost c om plete ly daily.
U p o n w a t e r e x c h a n g e , t h e s u r v i v al w a s d e t e rm i n e d .
E xp er im ent 8
To av o id th e u se o f d ru g s a s a p ro p h y lax is, d i r ec t o zo
n a t i o n o f th e c u l t u r e t a n k s w a s t e s t e d i n a e r a te d 1 L
p la st ic co ne s. O zon e ( 0 3) w as in je c te d d ir ec tl y v ia a n
a i r s to n e i n t o e v e r y la r v a l r e a r i n g e o n e u p o n c h a n
g in g w a te r an d feed d a ily. S ix t r ea tm en ts w i th th ree
rep l ica te s we re a r ran g ed co n s i s t in g o f a co n t ro l
(wi th o u t 0 } ap p l ica t io n ) an d 0 3 in jec tio n fo r 2 , 4 , 6,
8 a n d 1 0 m in (e q u iv a len t to a r e s id u a l 0 3 leve l in th e
w a te r o f 0 ,0 6 ,0 ,1 2 ,0 .1 5 ,0 .1 7 an d 0 .1 9 mg L " 1 a s m ea
su red b y a t e s t k i t u p o n f in i sh in g th e in jec t io n ) . O th e r
r e a r i n g c o n d i ti o n s a n d d a i ly m a n a g e m e n t w e r e s im i
la r to th o se d e sc r ib ed fo r ex p e r im en t 7 .
Evaluation criteria
Th e su rv iv a l r a te s in th e ex p e r imen ts u s in g la rg e
(3 0 -1 0 0 L) co n ta in e r s ( ex p e r imen ts 1 -6 ) we re e s t i
ma ted b y v o lu me t r ic samp l in g . Dep en d in g o n th e
tan k v o lu me an d th e d en s i ty o f th e su rv iv in g la rv ae ,
t r ip l ic a t e 3 0 0 - 1 0 0 0 m L s a m p l e s w e r e t a k e n f ro m
each tan k . M eg a lo p ae (M ) (DAH 1 5 -1 8 ) an d f i r s t
crabs (C l) (DAH 22) wer e coun ted individually . In ex
p e r im e n ts 7 a n d 8 (u s in g sm a ll co ne s) , th e av er ag e
su rv iv a l r a te was ca lcu la ted b y in d iv id u a l ly co u n t in g
a l l su rv iv in g la rv ae in ea ch rep licate .
La rv a l d ev e lo p men t was mo n i to red ev e ry 3 d ay sb u t d ai ly in ex p e ri m en ts 7 a n d 8 b y id e n ti fy in g th e
av e rag e zo ea l in s ta r s tag e o f a samp le o f l a rv ae an d
assig ning i t a value: Z1 =1 , Z2 = 2 , e tc . Megalopa
s tag e was a s s ig n ed av a lu o f 6 . To co mp are th e l a rv a l
d ev e lo p men t in each t r ea tme n t , an av e rag e la rv a l
s tage index (LSI) was calcula ted from the average
LSI v a lu e o f a ll r ep l ica te co n ta in e r s in th e sa m e t r ea t
ment. For large conta iners (experiments 1-6) , f ive or
10 larva e ( in 30 a nd 100 L tan ks respectively) were
2007 The AuthorsJournal Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Rese arch, 38, 1539-1553 1543
-
7/26/2019 kepiting (2)
6/15
Improved rearin g techniques for mud crab larvae T T Nghia e t al. A quaculture R esearch. 2007, 38, 1539-1553
Ta ble 3 Experim ent 1: survival rates an d larval stage index (LSI) values of Scylla paramamosainlarv ae cultur ed in two differ
ent rearing systems
Days af ter hatch
Treatment 3 6 9 12 15 18
Survival rate (%)*
Clear-Batch 85 6a 79 9a 70 6a 64 7a 42 6b 32 5b
Clear-Recirc 84 4a 78 8a 72 5a 70 5a 63 9a 4 7 6 a
LSI
Clear-Batch 1.5 0.2a 2.7 0.1a 3.5 0.4a 4.0 0.0a 4.6 0.2a ND
Clear-Recirc 1.5 0 ,2a 2.7 0.1a 3.6 0.3a 4.2 0.3a 4.8 0.1a ND
Survival rates or LSI values in the sam e colum n followed by the same superscrip t letter are not statistically different (P > 0.05).
For treatm ent des criptions, refer to Table 1.
ND, no t d ete rm ine d.
samp led f ro m ea ch ta n k to ca lcu la te th e av e rag e LSI .Th e samp led la rv ae we re s tag ed u n d e r a d i s sec t in g
mic ro sco p e . In ex p e r im en t 8 , u s in g sma l l co n ta in e r s ,
a l l l a rv ae we re s tag ed v i su a l ly u p o n co u n t in g d a i ly
survival .
In th i s r e sea rch , s ix l a rv a l r ea r in g sy s tems were
ap p l ied fo r th e ex p e r imen ts . Each rea r in g sy s tem
h ad i t s o w n fea tu re s, i .e . wa te r q u a l i ty an d ea se o f
opera tion. Therefore , the se feature s in comb ination
m a d e u p a t r e a t m e n t a s a t y p e o f r e a r in g s y s t em . T h e y
were n o t co n s id e red a s v a r iab le s.
Statistical analysis
On e-way an a ly s i s o f v a r ian ce (anova) was u sed to
co mp are d a ta . Ho mo g en e i ty o f v a r ian ce was te s ted
wi th th e Lev en e s ta t i s t i c (P o r a v a lu e was se t a t
0 .05) . I f no s ignif icant d ifferences were detected be
t w e e n t h e v a r i a n ce s , t h e d a t a w e r e s u b m i t te d t o a
o n e -way an o v a . Tukey 's honestly s ignif icant d iffer
en ce p o s t h o c an a ly s i s was u sed to d e tec t d if f e ren ces
b e tw e en m e a n s a n d to in d ic a te a r e a s o f s ig n if ic an t
difference. I f s ignif ica nt d ifferences were d etected
b e tw e en v a ri a n ce s , d a ta w er e tr a n s fo rm e d u s in g th e
a rc s in e - sq u a re ro o t ( fo r p e rcen tag e d a ta , i .e . su rv iv a l
ra te ) o r lo g a r i th m ic t r an s fo rm a t io n s ( fo r LSI v alu e )
(Sokal & Rohlf 1995). All analyses w ere perform edu s in g th e s ta t i s t ic a l p ro g ram s t a t i s t i c a 6 .0 .
Results
Experiment 1
Su rv iv a l in th e Clea r -Rec irc sy s tem a t Z4 -Z5 s tag es
o n DAH 1 5 an d in th e meg a lo p a s tag e o n DAH 1 8
w a s s i g n i f i c a n t l y h i g h e r t h a n t h o s e i n t h e C l e a r -
Batch sy stem (both a t P < 0.01) (Table 3). A lthou ghs l ig h t ly h ig h e r in th e r ec i rcu la t in g sy s tem, LSI was
n o t s ig n i f ican t ly d i f f e ren t b e tween t r ea tmen ts . Th e
b e tt e r la rv a l p e rf o rm an c e in th e C le ar -R ec ir c sy st em
was acco mp an ied b y s ig n i f ican t ly lo wer av e rag e
ammo n ia l ev e l s (PcO.Ol) an d s l ig h t ly lo wer n i t r i t e
levels (se e Tab le 2).
Experiment 2
On DAH 9, larval survival in the Clear-Recirc system
was s ig n i f ican t ly lo wer (P < 0 .0 5) th an in b o th t r ea t
me n ts wi th m ic ro -a lg ae su p p lem en ta t io n (Alg ae -Re
circ and Green -Batch sy stems) (Table 4) . On DAH 12,su rv iv a l in th e Clea r -Rec i rc t r ea tm en t was lo w er
(P < 0 .0 5) th an in th e Alg ae -Rec i rc sy s tem, w h e reas
th e Green -Ba tch sy s tem h ad in te rmed ia te r e su l t s .
The LSI values on DAH 15 show a s imilar trend,
a l th o u g h n o t s ig n i f ican t ly d i ff e ren t.
Th e av e rag e lev e l s o f ammo n ia an d n i t r i t e in th e
Clear-Recirc and Algae-Recirc systems were s ignif i
can t ly lo wer (P < 0 .0 1) th an th o se in th e G reen -Ba tch
system (see Table 2). In th e Green-B atch system,
p ea k s o f am m o n ia a n d n it ri te co n cen tr a ti o n s o f 3
an d 1 mg L " \ r e sp ec tiv ely , we re r eco rd ed a t th e en d
o f t h e e x p e r i m e n t .
Experiment 3
Tab le 5 p re sen ts th e l a rv a l p e r fo rman ce o f th e c rab
la rv ae cu l tu red in two rea r in g sy s tems . Th e su rv iv a l
ra te s an d LSI v a lu es o f b o th r ea r in g sy s tems w ere n o t
s ignif icantly d ifferent . However, the su rvival ra tes on
la ter days (from DAH 12- 22) i n the Green-Recirc sys
tem ten d ed to b e h ig h e r th an th o se in th e Green -
Batch system. The biofi l ter had a posit ive impact on
1544 2007 The Authors
Journ al Compilation 2007 Blackwell Publishin g Ltd. Aq ua cu ltu re Research, 38, 1539-1553
-
7/26/2019 kepiting (2)
7/15
A q ua cu lt ur e R es ea rc h, 2 007 , 3 8 , 153 9-1 553 Im pro ved r ea ri ng t e c h ni q u es for m u d c ra b l ar va e T T Nghia et al.
Ta ble 4 Experiment 2: survival rates and larval stage index (LSI) values of Scylla paramam osain larvae cultured in three
different rearing systems
Treatment
Days af ter hatch
3 6 9 12 15
Survival rate (%)*
Clear-Recirc 74 12a 63 7a 44 6b 26 11b 8 7 a
Algae-Recirc 74 12a 63 9a 61 7a 43 7a 15 8a
Green-Batch 74 11a 67 9a 58 9a 35 9ab 13 6a
LSI*
Clear-Recirc 1.9 0.1a 2,7 0.2a 3.9 0.1a 5.0 0.1a 5.1 0.1b
Algae-Recirc 2.0 0.1a 2.8 0.3a 4.0 0.1a 5.0 0.1a 5.6 0.2a
Green-Batch 2.0 0.1a 2.8 0.2a 4.0 0.1a 5.0 0.1a 5.1 0.1ab
Survival rates or LSI values in th e same column followed by the same superscript lett er are no t statistically different (P > 0.05).
For treatment descriptions, refer to Table 1.
Ta ble 5 Experiment 3: survival rates and larval stage index (LSI) values of Scylla paramamosainlarvae cultu red in two dif
ferent rearing systems
Days af ter hatch
TVeatment 3 6 9 12 15 22
Survival rate (%)*
Green-Batch 94 6a 88 x 9a 80 3a 66 15a 44 20a 9 1a
Green-Recirc 94 6a 89 8a 80 5a 68 11a 56 11a 12 3a
LSI*
Green-Batch 1.4 0.3a 2.7 0.1a 3 .8 0.4a 5.0 0 .0a 5.2 0.2a ND
Green-Recirc 1.4 0.2a 2.6 0.2a 3 .9 0.3a 5.0 0.0a 5.3 0.1a ND
Survival rates or LSI values in the same column followed by the same superscript letter are not statistically different (P > 0.05).
For treatment descriptions, refer to Table 1.
ND, no t determined.
t h a t L S I w a s a l w a y s t h e l o w e s t i n t r e a t m e n t
3 0 r o t if e rs m L 1 a n d t h e h i g h e s t i n t r e a t m e n t
6 0 ro t i f e r s mL " \
Experiment 6
Tab le 8 p re sen ts th e su rv iv a l an d d ev e lo p men t r a te o f
crab larvae fed A rt em ia nau pli i a t th ree d ensit ies (10,
1 5 an d 2 0 mL : ) f ro m th e Z3 s tag e o n w ard s . No s ig
n i f ic an t d i ff e ren ces we re o b se rv ed b e tween th e t r e a t
men ts . Th e re seemed , h o wev e r , to b e a weak t r en d
to ward s h ig h e r su rv iv a l an d LSI wi th in c rea s in g
A rt em ia d en s i ty to ward s th e en d o f th e t r ia l .
Experiment 7
Tab le 9 sh o ws th e su rv iv a l an d d ev e lo p men t r a te to
the megalopa s tage (DAH 22) of larvae receiving dif
f e ren t p ro p h y lac t ic t r ea tmen ts . Fro m DAH 6 o n
ward s , th e su rv iv a l r a te o f l a rv ae in th e t r ea tmen t
w a t e r q u a l i t y i n t h e s e c o n d p a r t o f t h e e x p e r i m e n t,
w i t h s i g n i f i c a n t l y r e d u c e d a m m o n i a ( P < 0 . 0 5 ) a n d
n i t r i t e (PcO.Ol) co n cen t ra t io n s a s a co n seq u en ce
(seeTab le 2).
Experiment 4
Tab le 6 sh o w s th e su rv iv a l an d d ev e lo p men t r a te o f
crab larv ae s tocked a t fo ur d ifferent Z1 dens it ies (50,
100, 150 an d 20 0 L - *). Th e su rviv al ra tes w ere n ot
s ig n i f ican t ly d i f f e ren t amo n g t r ea tmen ts . On ly o n
DAH 6 was a n eg a t iv e co r re la t io n b e tween LSI an d
la rv a l d en s i ty o b se rv ed.
Experiment 5
Tab le 7 sh o ws th e su rv iv a l r a te s an d th e LSI v a lu es o f
c rab la rv ae fed th r ee d i f f e ren t ro t i f e r d en s i ti e s in th e
Z1-Z2 s tages. No s ignif icant d ifferences were found
fo r an y o f th e p a ram e te r s . I t c an , h o wev e r , b e n o t iced
2007 The AuthorsJournal Compilation () 2007 Blackwell Publishing Ltd, Aq uac ult ure Rese arch , 38, 1539-1553 1545
-
7/26/2019 kepiting (2)
8/15
Improved rearing tec hniques for mud crab larvae T T Nghia e t al. Aquaculture Research, 2007, 38, 1539-1553
Ta ble 6 Experim ent 4: survival rates and larval stage index (LSI) values of Scylla paramamosainla rva e stocked at four differ
en t 21 densiti es (2 1L ~*)
Treatment
Days af ter hatch
3 6 9 12 15 22
Survival rate (%)*
50 79 9a 56 19a 42 16a 31 17a 2 8 12a 4 6 a
100 80 T 74 6a 71 10a 56 11a 4 5 8a 5 4 a
150 79 2a 57 12a 45 9a 31 12a 28 10a 5 1a
200 85 5a 53 17a 42 8a 34 3a 30 5a 5 1a
LSI
50 1.7 0.23 3.0 0.1a 3 .9 0.1a 5.0 0.1a ND ND
100 1.8 0.1a 3.0 0.1ab 4 .0 0.0a 5.0 0.1a ND ND
150 1.8 i 0.2a 3.0 0.1ab 3 .9 0.2a 5.0 0.1a ND ND
200 1.8 0.2a 2.7 0.1b 3 .7 0.2a 4.8 0.1a ND ND
Survival rates or LSI values in the sam e column followed by the same sup erscrip t lette r are not statistically differe nt (P > 0.05).
ND, n ot det erm ine d.
Tab le 7 Experim ent 5: survival rates and larval stage index (LSI) values of Scylla paramamosainlarvae-fed three different
rotifer densities (rotifers mL ~ ) from day 0 to day 6 after hatch
Treatment
Days af ter hatch
3 6 9 12 15
Survival rate (%)*
30 89 I a 53 10a 30 8a 13 7a 10 7a
45 87 6a 58 9a 35 7a 18 9a 14 8a
60 87 5a 55 7a 32 6a 16 11a 11 1 0a
LSI*
30 1.8 0.2a 2.7 0.1a 3 .6 0.2a 3.8 0.2a 4.0 0.4a
45 1.8 0.2a 2.8 0.2a 3 .8 0.1a 3.9 0.1a 4.3 0.5a60 1.8 0.2a 2.8 0.2a 3 .8 0.2a 4.0 0.1a 4.4 0,5a
Survival rates or LSI values in the same column followed by the same superscript letter are not statistically different (P > 0.05).
u s in g an t ib io t ic s was s ig n i f ican tly h ig h e r th a n th o se
i n t h e r e m a i n i n g t r e a t m e n t s . T h e s u r v i v al r a t e s o f th e
c o n t r o l a n d f o r m a l i n t r e a t m e n t s w e r e s i m i l a r on
m o s t d ay s. Fro m DAH 6 o n w ard s , th e LSI v a lu es o f
t h e f o r m a l i n t r e a t m e n t w e r e g e n e r a ll y h i g h e r th a n
fo r th e o th e r t r e a tm en ts (n o t a lway s s ig n if ican t ). On
DAH 15 an d 1 8, th e an t ib io t ic t r ea tm en t r e su l ted in
lowe r LSI values (P < 0 .01).
Experiment 8
Tab le 1 0 p re sen ts th e su rv iv a l a t th e Z2, Z3 an d Z4
s tag es o f l a rv ae th a t w e re d a i ly ex p o sed to d i ff e ren t
levels of 0 3 . On DAH 3 (Z2 s tage) , surviva l in the con
t r o l a n d t h e t r e a t m e n t w i t h 0 3 in j e c ti o n f o r 2 m i n
( O z o n 2 ) w a s h i g h e r ( 6 7 - 7 8 % ) c o m p a r e d w i t h t h e
o th e r t r ea tm en ts (2 4 -4 5 %) . O n DAH 6 (Z3 stag e ),
t h e s u r v i v a l o f tr e a t m e n t O z o n 2 b e c a m e t h e h i g h e s t
(52%); however, th is was not s ta t is t ica l ly d ifferent
from the control (25%). On DAH9, there were no s ig
n i f ic an t d i f f e ren ces in su rv iv a l in a l l t r e a tmen ts .
Discussion
Rearing system
R ec ir cu la tion
W ate r r ec i rcu la t io n th ro u g h a b io fi l te r in th e Clea r -
Rec i rc sy s tem p o s it iv ely a f fec ted la rv a l p e r fo rman ce
c o m p a r e d w i t h m a n u a l p a r t i a l w a t e r r e p l a c em e n t i n
th e Clea r -Ba tch sy s tem (ex p e r imen t 1 ) . Th e ad v an
tag es o f r ec i rcu la t in g sy s tems in co mmerc ia l f i sh
an d c ru s tacean la rv a l p ro d u c t io n h av e b een p ro v en
b ef or e fo r o th e r sp ec ie s. R esea rc h in to r e c ir c u la ti n g
1546 2007 The Authors
Journal Compilation 2007 Blackwell Publi shing Ltd, Aq ua cu ltu re Research. 38, 1539-1553
-
7/26/2019 kepiting (2)
9/15
Aq uacu lture Research, 2007, 38 , 1539-1553 Improved rearing te chni ques for mud crab larvae T TN g hi a et al.
Ta ble 8 Experim ent 6: survival rates and larval stage index (LSI) values of Scylla paramamosainlarvae-fed th ree different
instar-1Artemiadensities (Artemia mL ^ 1) from 6 days after hatch
Treatment
Days af ter hatch
9 12 15
Survival rate (%)*
10 26 10a 12 5a 8 3
15 30 6a 13 7a 10 6a
20 32 8a 19 9a 18 9a
LSI*
10 3.1 0.2 3.7 0.4a 4.3 0.5a
15 3.1 0.1a 3.7 0.2a 4.3 0.5a
20 3.2 0.1a 3.8 0.3a 4.6 0.3a
* Survival rates o r LSI values in the same column followed by the same supersc ript letter are no t statistically different (P > 0.05).
Ta ble 9 Experim ent 7: survival rates and larval stage index (LSI) values of Scylla paramamosain larvae treated daily with
proph yla ctic chemica ls
Days af ter hatch
T reatm ent 3 6 9 12 15 18 22
Survival rates (%)*
Control 85 3a 64 1 48 8b 3 4 + 13b 28 11 b 17 7b 9 5b
Formalin 84 7a 66 8b 47 7b 34 12b 26 8b 13 10b 11 8ab
Antibiotics 91 4a 80 2a 74 4a 66 8a 52 6a 34 3a 21 5a
LSI*
Control 1.8 0.1 2.6 0 .3a 3.4 0 .2ab 4 .5 0.3a 5.1 0.1a 5.5 0.1b 5.8 0.2a
Formalin 1.8 0.1a 2.8 0 .1a 3,7 0 .1a 4 .3 0.3a 5.1 0.1a 5.8 0 .1a 6.0 0.1a
Antibiotics 1.9 0 .0a 2.7 0 .2a 3.3 0 .2b 4 .3 0.1a 4.9 0.1b 5.3 0 .2b 5.6 0.2a
"Survival rates or LSI values in the same column followed by the sa me superscrip t lette r arc not statistic ally different (P > 0.05).
Ta ble 10 Experim ent 8: survival rates of Scylla paramamosainlarvae treated daily by ozone for different durations of time
(min)
Treatment DAH 3 (Z2) DAH 6 (Z3) DAH 9 (Z4)
Control 78 6a 25 9ab 9 6a
Ozon2 67 6ab 52 14a 11 10a
Ozon4 40 17abc 33 11ab 5 2a
Ozon6 45 25abc 27 15ab 5 5 a
Ozon8 31 2bc 19 3 b 0 0 a
OzonlO 24 15c 12 9b 0 1a
Survival rates in t he sa me column followed by the sam e superscript lette r are not statistically different (P > 0.05).
DAH, days after hatch; Z, zoea; Control, without ozonation; Ozon2,4, 6,8 and 10, duration of ozone injection from 2 to 10 min, which isequiv alent to 0.06,0.12, 0.15, 0.17 and 0.19 mg L " 1 of the residual ozone respectively.
sy s tems h as a l so b een id en t i f i ed a s a p r io r i ty fo r
sh r im p c u l tu re (Lawren ce & Lee 19 97 ). In th e se sy s
t e m s , w a t e r e x c h a n g e i s m i n i m i z e d t h r o u g h t h e u s e
o f b io lo g ica l , ch em ica l an d /o r m ech an ica l f i l t r a tio n
to m a in ta in g o o d w a te r q u a l i ty co n t in u o u sly . As th ey
p ro v id e le ss s tr e s s a n d co n fe r c o n s ta n t go od w a te r
q u a l i ty to th e l a rv ae , th e se sy s tem s a re ab le to ma in
ta in a h ig h b io lo g ical c a r ry in g cap ac i ty in r e la t iv e ly
li t t le space (Quil lere , Marie , Roux, Gosse & Morot-
g au d ry 1 99 3; Twaro wsk a , W es te rman & Lo so rd o
1997). For crab larviculture , rec ircula t ing systems
a lso ap p ea r to w a r ran t fu r th e r in v es t ig a tio n in o rd e r
to d ec rea se l ab o u r r eq u i remen ts an d seawa te r co n
su mp t io n , p ro v id in g a mo re s tab le cu l tu re med iu m
2007 The AuthorsJournal Compilat ion 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Resea rch, 38, 1539-1553 1547
-
7/26/2019 kepiting (2)
10/15
Improved rearing techniques for mud crab larvae T T Ngh iaet al. Aquaculture Research. 2007, 38, 1539-1553
an d thu s reduc ing la rva l s t ress . I f the sys tem des ign
is kept simple, recirculating system s could also be sui
tab le fo r la rge-sca le p roduc t ion .
Ro le o f su pp le m en te d m ic ro a lg ae
The a dd i t ion o f m icro-a lgae to the rec i rcu la t ion
s y s t e m s r e s u l t e d i n b o t h h i g h e r s u r v i v a l a n d f a st e r
deve lopment in th is s tudy . Micro-a lgae have been
p ro v en to b e ben ef ic ia l by v ari o u s m odes o f act io n .
The y cou ld he lp m ain ta in the qua l i ty o f l ive food . As
i n t h e c u l t u r e o f m a r i n e f i s h l a r v a e , u n c o n s u m e d
ro t i fe rs may res ide in the tan ks fo r severa l days and
the i r nu t r i t iona l va lue may become severe ly reduced
(Makridis & Olsen 1999). Furthermore, according to
these au thors , poor ly fed ro t i fe rs were m ore sens i tive
to s ta rva t io n th an wel l -fed ro t ife rs, a s th e i r n i t roge n
c o n t e n t d e c r e a s ed a t a h i g h e r r a t e.
M icro-a lgae a lso play an imp or tan t ro le in s tab i l iz
i n g w a t e r q u a l i ty v i a e i th e r a m m o n i a u p t a k e o r o xy
gen pro du ction (Tseng, Hu ang & Liao 1991). Because
the C lear -Rec i rc sys tem a l ready prov ided op t imal
w ate r qua l i ty , i t i s un like ly tha t the s tab i l iz ing e f fec t
on w ate r qua l i ty i s respons ib le fo r the improved per
fo rmance in the a lgae-supplemented sys tem. In
b a tc h c u l tu r e sy st em s, th is ef fe ct w o uld p ro b ab ly be
m u c h m o r e p r o n o u n c e d . A d ir e c t c o m p a r i s o n
b e tw e e n a g re e n a n d c le a r w a te r b a tc h sy s te m wa s,
however , no t mad e in th is study .
In a s tudy on th e e f fec t o f Chlorellao n t h e p o p u l a t i o n o f l u m i n o u s b a c t e ri a Vibrio ha rveyi,n o l u m i n o u s
b a c te r ia w ere re co vere d o n da ys 2 a n d 3 in fl as ks
w i t h Chlorella, w h i l e t h o s e w i t h o u t t h e m i c r o -a l g a e
s t il l ha rbo ured lum inous bac te r ia a t day 3 (Tendenc ia
& dela Pena 2003). Also, the diatom Chaetoceros has
b e en s h o w n to p ro duce n a tu ra l an ti b io ti cs a n d h ig h
concen tra t ions o f th is mar ine d ia tom wi l l e l im ina te
Vibrio vulnificus and o the r pa thogen ic bac te r ia , which
con tr ibu te to the p ropaga t ion o f v i ruses in the shr imp
p ro d u c ti o n e n v ir on m en t ( W an g 2 00 3) .
I n c o n c l u si o n , m i c r o - al g a e i n m u d c r a b l a r v a l r e a r
ing m ay p lay a ro le in improv ing and m ain ta in ing l ive
food qu a l i ty and con tro l l ing bac te r ia leve ls.
Choice o f system
In ex per im ent 3 . the Green-Rec i rc sys tem (which i s a
c o m b i n a t i o n o f a G r e e n -B a t ch s y s t e m d u r i n g t h e r o
t i fe r feed ing s tage and a A lgae-Rec i rc sys tem there
a f te r ) seemed to be be t te r than the Green-Batch
sys tem. The Green-Batch sys tem seems to be more
appro pr ia te fo r ea r ly s tages o f c rab la rvae (Z1-Z2) as
i t is le ss s tress fu l fo r the ea r ly zoeae an d e as ie r to g ra
dua l ly f il l up the tank s w i th f res h seawate r , a lgae and
ro t i fe rs than f lush ing ou t o ld ro t i fe rs in the rec i rcu la
t ion sys tem. In the rec i rcu la t ing sys tem, the youngl a r v a e m a y b e p r o n e t o p h y s i c a l d a m a g e a n d m a y
s p e n d c o n s id e r ab l e e n e rg y t r y i n g t o s w i m u p a g a i n s t
the cu r ren t . Ear ly c rab la rvae a re de l ica te due to the i r
s m a l l si ze a n d t h e t h r e e l o n g s p i n e s o n t h e c a r a p a c e
t h a t a r e e a s il y d am a g e d i v h e n t h e y a r e e n t r a p p e d o n
t h e m e s h s c r e e n d u r i n g f l u s h i n g o u t o f u n e a t e n f e ed
in the rec i rcu la t ion sys tem (Davis 2003) . The nu t r i
t iona l e ffect o f m icro-a lgae i s p ro bab ly a lso mo re p ro
n o u n c e d d u r i n g t h e r o t if e r f e e d i n g s t a g e t h a n d u r i n g
t h e A rt em ia feed ing s tage . Fur the rm ore , i t is no t ne
cessa ry to rec i rcu la te wate r dur ing these f i r s t days ,
a s t h e c o n c e n t r a t io n s o f a m m o n i a a n d n i t r i t e a r e s ti l l
low. Using th e Algae-Recirc sys tem in later stag es ism o r e f a vo u r ab l e fo r re d u c i n g t h e i n c r e a s i n g a m m o
n i a a n d n i t r i t e c o n c e n t r a ti o n s a s m o r e w a s t e m a t e r i
a l i s p roduced by the c rab la rvae . Moreover , a s the
larvae develop into more efficient predators, feed is
c o n s u m e d f a s te r , a n d m a i n t e n a n c e o f o p t i m a l f e ed
qua l i ty i s less o f an i ssue. M any s tud ie s successfu l ly
app l ied a s im i la r combined rea r ing techn ique d ue to
i t s benef i t fo r the la rvae and conv en ience fo r ma n
agement . pa r t icu la r ly fo r la rge rea r ing con ta iners .
Under g reen-wate r cu l tu re condi t ions , wa te r i s no t
exchang ed fo r the f i r st 3 days . The reaf te r , wa te r ex
chang e i s s lowly increased f rom 1 0-20% day 1 fo r
Z 2 - Z 3 t o b e t w e e n 4 0 % a n d 5 0% d a y ~ 1 a t t h e e n d o f
the rea r ing cyc le (Z4-M) (Mann , Asa kaw a & P izzu to
1999; Quinitio. Parado-Estepa, Millamena. Rodriguez
& Bor longan 2001) . In Japan , a m esocosm sys tem is
used fo r cu l tu r ing la rvae in la rg er ta nk s ( > 10 m3).
The tank s a re p ar t ia l ly f il led w i th g ree n w ate r a t Z1
(20-25% volume), tanks a re then f i lled up w i th c lean
s e a w a t e r d u r in g t h e c o u r s e o f t h e Z 2 - Z 3 s t a g e s a n d
dur ing th e Z4 and M s tages wate r i s exchang ed on a
flow-to-waste basis (Hamasaki, S upray udi & Takeu chi
2002).
Other rearing techniques
ZI st oc ki ng den si ty
No si g n if ic an t ef fe ct of la rv a l d e n s it y w as ob se rv ed
from 50 to 200 Z1L-1 . Th is would sugges t tha t the
l a r v a e c a n b e g r o w n a t 2 0 0 Z l L ~ \ V a r ia t io n i n t h e
f inal su rv iva l be tween rep l ica te tanks a lso seemed to
decrease a t h igher dens i t ies . For S. paramamosain,
Djunaidah, Mardjono, Wille. Kontara and Sorgeloos
(2001) found a tenden cy of inc reased surv iva l to Z5
as a func t ion o f the Z l s tock ing den s i ty ( i.e . su rv iva l
1548 2007 The Authors
Journal Compilat ion 2007 Blackwell Publishing Ltd, Aqu acu ltu re Research, 38, 1539-1553
-
7/26/2019 kepiting (2)
11/15
Aqu acultu re Research. 2007, 3 8, 1539-1553 Improved rearing techniques for mud crab larvae T T N g h i a et al.
ra tes o f 27%, 39% and 63% be ing ob ta ined a t dens i
ties of 50,75 an d 100 Zl L 1 respectively). Baylon an d
Fai laman (1999) a lso repor ted h igher su rv iva l and
m e t a m o r p h o s i s o f Scylla serrata a t 5 0 Z 1 L - 1 c o m
p a re d w it h lo w er d en si ti es o f 10 a n d 25 Z l L ~ x. I n
c reased surv iva l a t h igher la rva l dens i t ies someho w
seem s contradictory . However, indirectly, food ration
migh t be respons ib le . Excess food in t rea tments w i th
low la rva l dens i t ies may po l lu te the wate r and may
thus cause m or ta li ty . In our s tudy , we no ted h igher
c o n c e n t r a t io n s o f a m m o n i a a n d n i t r i te i n t h e t r e a t
m ent hav ing 50Z 1L -1 (seeTable 2). For the h ighes t
stock ing dens ities tested in ou r s tudy (200 Zl L ~ x),
the la rva l deve lopment ra te seem ed s l igh t ly impaired .
This h igh s tock ing dens i ty may have caused compet i
t ion fo r feed, resu l t ing in s lower deve lopment . There fo re , Z l s tock ing dens i t ies in the range o f
1 0 0 - 1 5 0 Z l L 1 m i g h t b e o p ti m a l.
R o ti fe r den s it y fo r fee di ng e ar ly la rv al s ta ge s (Z 1Z 2
sta ges)
A l t h o u g h t h e r e w a s a t r e n d t o w a r d s i n c r ea s e d s u r v i
va l and grow th w i th increas ing ro t i fe r densi ty , no s ig
n i f ican t d i f fe rences in la rva l su rv iv a l o r g row th were
foun d be tween the d i f fe ren t ro t ife r dens i t ies tested .
A l though no t s ign i f ican t , the h ighes t su rv iva l was
genera l ly observed a t 45 ro t i fe rs mL - \ whi le a den
s i ty o f 60 ro t i fe rs mL ~ 1 resu l ted in the fas tes t la rva l
developm ent. Th e differences were, however, not very
m a r k e d , a n d m o r e o v e r s u c h h i g h f e ed i ng r a t e s m i g h t
be eco n o m ic a ll y u n re a li s ti c . We c a n th ere fo re co n
c lude th a t feed ing 30 ro t ife rs mL - 1 is enough fo r op
t im al la rva l pe r fo rmance . In p rac t ice , however , the
in te rme dia te dens i ty o f 45 ro t i fe rs mL _ 1 was f re
quen t ly used fo r feed ing ea r ly la rva l s tages . O ther
s tud ies ind ica ted tha t h igh ro t i fe r dens i t ies
(30-8 0 mL -x) a re req u i red fo r op t imal g row th and
surv iva l o f S. paramamosain (Djunaidah, Mardjono,
Lavens & Wille 1998; Zeng & Li 1999) and S. serrata
(Suprayudi, Takeuch i , Ham asak i & Hirokawa 2002) .
For S. paramamosain larvae, feeding 30 and
60 ro t ife rs mL ~ 1 resu l ted in a s ign i fican t ly h ighersurv iva l compared wi th feed ing on ly
15 r ot if e rs m L 1 ( D j u na id a h et al. 2001). These
a u t h o r s f o u n d t h a t t h e i n d iv i d u a l d r y w e i g h t o f Z5 -
fed 15 ro t i fe rs mL ~ 1 was s ign i f ican t ly lower than
those o f Z5 fed w i th h ig her ro t i fe r dens i ties . P rac t i
ca lly , feed ing 30 ro t i fe rs mL " 1 a t Z l and increas ing
grad ua l ly to 4 5 mL " 1 a t Z2 proved to be suf fic ien t
fo r a s tock ing d ens i ty o f 100 Z l L ~ 1 in ou r t r ia ls in la r
ger rea r ing tan ks (500 -100 0 L). Increas ing the ra
t i o n b y l a r v a l s t a g e s i n t h i s w a y c o m p e n s a t e s f o r
t h e i n c r e a s e d i n g e s t i o n o f cr a b l a r v a e a s t h e y g r o w
(Baylon, Bravo & Manigo 2004). For early larvae,
h o w ev e r, f o od a m o u n t c a n n o t b e r e d u c e d t o t h e i r
m a x i m u m i n g e s t i o n p o t e n t ia l a s t h e y a r e q u i t e i ne ff i
c i e n t p r e d a to r s a n d t h e re f o r e m i g h t r e q u i r e a m i n i
m a l d e n s i t y t o m a x i m i z e e n c o u n t e r .
S i m i la r t o o u r s t u d y m o s t s t u d i es i n v e s t ig a t in g t h e
ef fec t o f ro t i fe r den s i ty added the l ive food in one s in
g le ra t ion . Under th ese c i rcumstances , theore t ic den
s i t ies a re on ly a t ta ined upon feed ing and gradua l ly
decrease as la rvae consume the p rey . Opt imal l ive
food quan t i t ies cannot , however , be separa ted f rom
feed ing f requency . Be cause zoea la rvae can consum e
t h e i r o p ti m a l r a t i o n w i t h i n l h , G e n o de p a , S o u t h g a te
and Z eng (2004) sugg es ted th a t they can be fed oncea day . Because o f th e severe reduc t ion in the nu t r i
t iona l va lue o f ro t i fe rs w i th longer re te n t ion t imes in
rear ing c on ta ine rs (M akr id is & Olsen 1999) and the
f a c t th e r e i s a m i n i m u m p r ey d e n s i ty n e e d e d f o r t h e
pa ss iv e f eed in g b e h a v io u r o f zo ea la rv a e (H ea sm a n &
Fielder 1983; Zeng & Li 1999), th e inte ractio n betw een
the op t imal ra t ion and feed ing f requency should be
fur th er inves tiga ted .
A rt em ia fo r fee d in g l a te r la rv al st ag es (fr om Z3
onwards)
We found no d i f fe rence be tween feed ing Z3 a da i ly
feed ration of 10, 15 or 20 A rt em ia n a u p l ii m L - 1 .
Especially in later larval stages (Z4-Z5), there was,
however , a tendency towards h igher su rv iva l w i th
increas ing ra t ion . In th is respec t , i t m igh t be benef i
c ia l to inc rease th eA rt em ia dens i ty by c rab s tage f rom
10 to 15 m L 1 . H igh l ive feed dens i t ies would in
c r e a s e t h e c h a n c e f o r e a rl y l a rv a e t o e n c o u n t e r a n d
cap ture feed o rgan isms (Zeng & L i 1999) and the re
fo re would improve the la rva l pe r fo rmance (Br ick
1974; He asm an & Fielder 1983; Q uinitio et al. 2001).
On the o ther han d , o lder la rva l have a h igher inges
t ion capaci ty. Opt imal ra t ions sh ou ld there fore be de
te rmined fo r each la rva l s tage separa te ly . In th is
respec t , s tud ies on ind iv idua l la rvae a re very usefu lto de te rmine p rey consumpt ion . Accord ing to our
pr ev io u s ex p er im en ts (N ghia 20 04 ), e a c h Z3, Z4 , Z5
a n d m e g a l o p a l a r v a w a s c a p ab l e o f c o n s u m i n g o n
average 15. 25, 37 and 114 newly hatched
A rt em ia day - 1 respectively. Therefore, at a s tockin g
of 100 la rvae L - \ the d a i lyA rt em ia feeding densities
theoretically should be at least 1.5, 2.5, 3.7 and
11.4 mL ~ 1 for Z3, Z4, Z5 an d m egalo pa stages r espe c
tively. For Zl, Z2 and Z3 stages of S. serrata, th e
2007 The AuthorsJourna l Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Rese arch, 38, 1539-1553 1549
-
7/26/2019 kepiting (2)
12/15
Improved rearing techniq ues for mud crab larvae T T Nghia et al. Aqu aculture Research. 2007, 38, 1539-1553
n u m b e r o fA rt em ia naup l i i inges ted by the la rvae a t a
l o w e r f o od d e n s i t y o f 2 .5 m l - 1 w a s c o m p a r ab l e to
t h a t a t 5 m L - 1 , a n d f o r Z 4 - Z 5 , a t 5 m L - 1 , i t w a scomparab le to 10 mL -1 (Baylon et al. 2004). In that
study, A rt em ia was, however, co-fed with rotifers at a
d e n s i ty o f 1 5 - 2 0 m L ~ \ I fA rt em ia was th e on ly food,
the op t imal A rt em ia ra t ion w ould there fore p robab ly
be h ig h e r t h a n 2 .5 -5 m L - 1 . In a n o th e r s tu d y on S.
se rrata ,a da i ly op t im um food concen tra t ion o f 10Ar -
temia naup l i i mL " 1 wa s es tab l ished fo r zoea surv iva l
(Brick 1974). In th e m ass see d prod uction of S. serrata,
n e w l y h a t c h e d A rt em ia a re g iven s ta r t in g la te Z2 a t
0 . 5- 3 m L - 1 a n d 5 - 7 - da y - o ld A rt em ia a re ro u t ine fed
f rom la te Z5 to ea r ly m ega lopa (Quin i t io & Parado-
Estapa 2003). Older A r te m ia provided a larger-sized
p re y fo r zoea e to m eg a lo p ae a n d hen ce , th e dens it ywas reduced .
For mega lopae o f S. paramamosain, we found a
t h re e f o ld h i g h e r n u m b e r o f i n g e st e d n e w l y h a t c h e d
A rt em ia naup l i i compared wi th Z5 (114 and 37
A rt em ia respectively) for a similar prey density
(Nghia 2004) . Th is m ean s th a t mega lopae a re vora
c ious p reda tors , capab le o f chas ing the i r p rey ac t ive ly
and con sum e la rge am ou nts o f feed in a sho r t t ime .
From this, i t could be beneficial if megalopae are fed
f requen t ly sm al le r ra t ions in o rde r to op t im ize feed
q u a l i t y a n d r e d u c e c a n n i b a l i s m . G e n o d e p a et al
(2004) s im i la r ly ind ica ted tha t in con t ras t to ea r l ie r
la rva l s tages , wh ich c an be fed once per day, S. serrata
mega lopae may need to be fed more o f ten to maxi
mize inges t ion . These au thors found no s ign i f ican t
d i f fe rences in th e ing es t ion ra te o f mega lopae fed mi
c robound d ie ts a t ra t ions rang ing f rom 12 .5% to
100% of the s tan da rd ra t ion (equ iva len t to 5 A rt em ia
naup lii mL 1 in 1 h). Bay lon et al(2004) a lso found a
h igh increase in A rt em ia inges t ion in the f i r s t few
days o f the p lank to n ic ph ase o f the m ega lopa s tage.
La te r on , mega lopae become more ben th ic as they
p re p are fo r th e se c o n d m e ta m o rp h o s is to fi rs t cr ab .
S w i m m i n g A rt em ia are no longer accessible, and
m i n c e d s h r i m p o r m u s s e l m e a t a r e a m o r e s ui ta b l e
feed.
In conc lus ion , a ra t ion o f 10 A rt em ia n a u p l i i m L 1appears to be suf f ic ien t fo r the op t imal per fo rm ance
of Z3 la rvae . An inc rease in p rey den s i ty in the Z4-Z 5
stage may, however, be beneficial. These food
a m o u n t s a p p e a r t o b e h i g h e r t h a n w h a t m o s t o t h e r
s t u d i e s r e c o m m e n d ( 2 . 5 - 1 0 A rt em ia n a u p l i i m L -
Brick 1974; Bay lon et al.2004) . Perhap s the rec i rcu la t
ing sys tem used in th is s tud y resu l ted in a g rea te r loss
of p rey o rgan isms (e.g. mo re A r te m ia were en t rapped
o n t h e o v e r f l o w s c r e e n ) t h a n i n t h e s m a l l b a t c h
c u l t u r e s y s t e m s u s e d i n o t h e r e x p e r i m e n t s . T h e s m a l l
naup l i i s ize o f the A r te m ia s t r a i n ( V in h C h a u s t r a in )
u s e d i n o u r s t u d y c o u l d b e a n o t h e r r e a s o n t h a t l e dto increased inges t ion . In p rac t ice , ( la rger s ized)
h i g h l y u n s a t u r a t e d f a tt y a c i d - e n r i c h e d A rt em ia w e r e
n o r m a l l y u s e d i n o r d e r t o r e d u c e t h e p r e y a m o u n t t o
5 - 1 0 m L - \ Mega lopa p robab ly shou ld be fed more
f r e q u e n tl y a n d , t o w a r d s t h e e n d o f t h a t d e v e l o pm e n
ta l s tage , a non-m oving food may b e be t te r .
P ro ph yl act ic ch em ic al s
Labora to ry cu l tu res o f c rab la rva e o f ten suf fe r severe
mor ta l i ty f rom d isease , pa r t icu la r ly f rom ep ib io t ic
b a c te ri a a n d la rv a l m yco si s (A rm str o n g , B u c h a n a n
& Caldwell 1976; Ham asak i & H atai 1993a, b). A studyo n S. serrata ind ica ted a s ign i f ican t ly h igher su rv iva l
up to DAH 7 (over 90%) w hen u s ing Oxyte tracyc l ine ,
w h e r e a s a l m o s t c o m p l e t e m o r t a l i t y o c c u r r e d i n th e
c o n t r o l t r e a t m e n t ( M a n n 2 00 1) . T h e a u t h o r c o n s i d
e r e d t h a t p o t e n t i a l l y u p t o 8 0 % o f t h e l a rv a l m o r t a l it y
cou ld be a t t r ibu ted to bac te r io log ica l causes . The re
su l t s o f our s tudy a lso ind ica ted tha t bac te r ia a re ,
m o r e t h a n a n y o t h e r f a c t o r t e st e d , a m a i n c a u s e o f
la rva l mor ta l i ty . Ant ib io t ics more than doubled sur
v iva l up to the c rab s tage .
However , an t ib io t ics have no t a lways been used in
a r e s p o n si b l e m a n n e r i n a q u a c u l t u r e . A m a j o r c o n s e
quenc e o f us in g an t ib io t ics has been th e p ro l i fe ra t ion
o f r e s is t a n t b a c t e r i a a n d t h e t r a n s m i s s i o n o f r e s is
tance to o ther bac te r ia l spec ies (Benson 1998) . The
deve lopment o f an t ib io t ic res is tance by pa thogen ic
b a c te r ia is c o n s id e re d to be o n e of t h e m o st se ri o us
r isks to hum an he a l th a t the g loba l leve l (FAO 2002) .
Formal in i s more accep tab le than an t ib io t ics as i t
shows no accumula t ion in an imal t i s sues ( Jung ,
Kim, Jeon & Lee 2001). Recently, however, Ja pan has
s t r ic t l y b a n n e d t h e u s e o f f o r m a l in i n a q u a c u l t u r e a s
i t m a y c a u s e c a n c e r i n h u m a n s , r e d u c e s o x y g e n
levels in the w ater an d cau ses alg ae to die off (VASEP
2003) . Moreover , in ou r exper iments , fo rm al in d id no t
s ign i f ican tly improve la rva l su rv iva l compa red wi th
the nega t ive con tro l . Pa thogen ic bac te r ia a re cons id e red to be one o f the m ost se r ious causes fo r the h igh
mor ta l i ty o f ea r ly c rab la rvae . I t can be sa fe ly as
sumed that all inputs (seawater, broodstock, l ive feed
a n d d a i l y m a n a g e m e n t i n h a t c h e ri e s) i n t o t h e c u l
tu re tank a re po ten t ia l sources o f in fec t ion (B lack-
shaw 2001). Strict hygiene at all steps is always
advised for hatchery activities. However, this advice
is not always followed, especially in backyard
ha tcher ies . There fore , o ther techn iques shou ld be
1550 2007 The Authors
Journal Compilation ) 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Research , 3 8, 1539-1553
-
7/26/2019 kepiting (2)
13/15
Aquac ulture Research, 2007, 38 , 1539-1553 Improved rearing tech niq ues for mud crab larvae T T Nghia et al.
inves tiga ted as a l te rna t ives fo r th e u se o f chemica ls .
Ozona t ion and p rob io t ics cou ld be in te res t ing in th is
respect (Davis 2003; Nghia 2004). Ozone is a powerfu l ox idan t and is becoming m ore and m ore popula r
in var ious aquacu l tu re sys tems fo r d is in fec t ion and
improving wate r qua l i ty by ox ida t ion o f inorgan ic
and /o r o rgan ic compo unds (Tango & Gagno n 2003).
In o ur s tudy , d i rec t app l ica t ion d id no t s ign i f ican t ly
improve surv iva l comp ared w i th a nega t ive con tro l .
However, the re was a tenden cy of a res idua l 0 3 con
cen t ra t ion o f 0 .06 mg L ~ 1 to imp rove la rva l pe r fo r
mance . Var iab i li ty w i th in th is t re a tm ent was ,
however , ve ry h igh , wh ich cou ld be ind ica t ive o f the
fac t tha t dos ing was no t ca re fu l enough . Longer O3
exposure t imes (4 -10-min exposure , equ iva len t to
0 .12-0 .19 mg L _1 res idua l 0 3) a l l decreased overal lsu rv iva l . These h igh 0 3 conc en tra t ion s p robab ly
caused phys ica l dam age to the c rab la rvae . InPe na eu s
monodon juven iles , 0 .34-0 .5 m g L _1 res idua l 0 3
caused loss o f ba lance , immobi l i ty and des t ruc t ion
of the g i li lamel la r ep i the l ium (Meunpol , Lopinyos ir i
& Menasve ta 2003) . Ozone t rea tm ent sho u ld the re
fo re be inves t iga ted fu r ther , w i th de te rm ina t ion o f
p ro p er d os es fo r e a c h la rv a l st age . U lt im at el y, th e m i
crobial f lora will need to be controlled and there is
ev idence tha t th is can be ach ieved us ing rec i rcu la t
i n g s y st e m s i n w h i c h 0 3 t r e a t m e n t i s c o m b i n ed w i t h
the inocu la t ion o f the b io log ica l f i l te r w i th se lec ted
nitrifying and probiotic bacteria (Gatesoupe 1991;
Rombaut, Suantika, Boon, Maertens, Dhert.Top, Sor
geloos & Verstraete 2001).
Conclusions and suggest ions
The combina t ion o f a g reen-wate r ba tch sys tem for
ear ly s tages and a rec i rcu la t ing sys tem wi th micro
a lgae supp lementa t ion fo r la te r s tages , a s tock ing
d e n s i ty o f 1 0 0 - 1 5 0 Z 1 L - 1 , f e ed i n g d e n s i t y o f 3 0 -
45 ro t i fe rs mL _ 1 fo r ea r ly s tages and 10-15 A rt em ia
n a u p l i i m L - 1 f or l a t e r s t a g e s a r e r e c o m m e n d e d f or
la rva l rea r ing o f S. paramamosain.
The op t imal ra t ion fo r c rab la rvae shou ld , however ,be a d ju s te d d ep e n d in g o n v ar io u s f act o rs , e .g. sp ec ie s,
la rva l s tages, la rva l s ta tus , p rey s ize, rea r in g sys tem
and rea r ing techn iques . A feed ing reg ime wi th
f requen t add i t ion o f smal l qua n t i t ies o f feed i s wor th
investigating.
Ant ib io t ics improved la rva l su rv iva l , p rov ing
aga in tha t bac te r ia l in te r fe rence i s one o f the m ajor
cause s o f mor ta li ty . Formal in cou ld no t s ign i f ican t ly
improve surv iva l compared wi th the con tro l . Both
p ro du ct s, m o re o v er, a re n o t e n co u ra g e d fo r c o m m er
c ia l mu d c rab la rv icu l tu re as they a re unsafe . D irec t
ozona t ion as an a l te rn a t ive to p rophylac t ic chemica lsis wor th inves t iga t ing .
Acknowledgment s
T h i s st u d y w a s s u p p o r t e d b y t h e E u r o p e a n C o m m i s
s ion ( INCO-DC) th ro ug h th e p ro jec t g r an t No ICA4-
CT-2001-10022 C ul tu r e and m anag em ent o f Scylla
species, the F lem ish Inter-University C ouncil (VLIR-
IUC) and the In te rna t iona l Founda t ion fo r Sc ience
( IF S) t h r o u g h t h e r e s e a r c h g r a n t a g r e e m e n t N o A /
2505-1 Imp rovem ent o f la rv icu l tu re o f the m ud c rab
(Scylla paramamosain) in th e M ekong Delta, Vietnam .
References
Angeli C. A. (1992) The mu d crab In: Report o f the Semi nar on
the Mud Crab Culture and Trade (BOBP/REP/51, B ay o f
Bengal Programme, Madras, India),Surat Thani, Thailand.
5-8 November 1991 (ed. by C.A. Angeli), 246pp.
Armstrong D.A., Buchanan D.V & Caldwell R.S. (1976) A
mycosis caused by Lagenidiumspp. in laboratory reared
larvae of the D ungeness crab, Cancer magister,an d possi
ble chem ica l tr ea tm en ts . Journal o f Invertebrate Pathology
28, 329-336.
Baylon J.C. & Failama n A.N. (1999) Larval rear ing of mud
crab Scylla serratain t he Philippines. In:Mu d Crab Aqua-
culture and Biology, Proceedings of an Internationa l Scienti-
fic Forum, Darw in, Australia, 21 24 Apr il 1997, AC1AR
Proceedings No. 78 (ed. by C.P. Keenan & A. Blackshaw),
pp. 141 -14 6. Au st ra lia n Cen tre f or In te rn at io na l Agri cu l
tural Research, Canberra, Australia.
Baylon J.C., Bravo M.E.A. & Manigo C. (2004) Ingestion of
Brachionus plica tilis and Artemi a salin a nauplii by mud
crab Scylla serratalarvae.Aquacultu re Research35,62-70.
Benson S.M. (1998) Reservoirs of resistance. Todays Life
Science10.
Blackshaw A.W. (2001) Larval culture o Scylla serrata:main
tenance of hygiene and con cepts of experimental design.
Asia n Fisheries Science 14,239-242.
Brick R.W. (1974) Effect of water quality, antibiotics, phytopl an kt on a nd food o n su rv ival a nd dev elo pm ent of la rvae
of Scylla serrata (Crustacea: Portunidae). Aquacul ture 3,
231-244.
Davis J.A. (2003) Develo pment of h atche ry techniques fo r the
mud crab Scylla serrata (Forsskl) in South Africa.PhD the
sis, Faculty of Agricultural and Applied Biological
Sciences, Ghent University, Belgium, 163pp.
Dh ert P. (1996) Rotifers. In: Manua l on the Production and Use
of Live Food fo r Aquaculture. FAO Technical Paper No. 361
(ed. by P Lavens & P. Sorgeloos), pp. 61-100. Food and
2007 The AuthorsJournal Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Resea rch, 38, 1539-1553 1551
-
7/26/2019 kepiting (2)
14/15
Improved rearing tech niques for mud crab larvae T T Ngh ia et al. Aqua culture Research , 2007, 38, 1539-1553
Agriculture Organization of the United Nation, Rome,
Italy.
Djunaidah I.S., Mardjono M Lavens P. & Wille M. (1998)Effects of light and feeding regimen on culture perfor
mance of mud crab (Scyllaspp.) larvae. In: Culture of Por
tunid Crabs, Extended Abstracts of the International Forum,
Boracay, Philippines, 1 -4 December 1998 (ed. by C. Keen
an, 0. Millamena & E.T. Quinitio), pp. 27-28. SEAFDEC,
Tigbauan, Philippines.
Dj un aid ah I.S., Mardjon o M., Wille M., Kontara E.K. & Sorge
loos P. (2001) Investigations on sta ndard rearing techni
ques for mass prod uction of mud c rab Scyllaspp. seed. A
research review. In: Mud Crab Rearing, Ecology and Fish-
eries, Book of Abstracts of 2001 Workshop,CanTho Univer
sity Vietnam, 8-10 January 2001 (ed. by L. Le Vay, P.
Sorgeloos, M. Wille, T.T. Nghia & VN. Ut), p. 11. Institute
for Marine A quaculture (IMA) - Can Tho University, Can
Tho City, Vietnam.FAO (1999)Aquacul ture production statis tics 198 81 997 .FAO
fishe ries Ci rcu lar No. 815, Revision 11, Rome, Italy, 203 pp.
FAO (2002) The state of world fisheries a nd aquacultu re. See
http://wwiv.fao.org/docrep/
Gatesoup e F.J. (1991) The effect of thr ee st rain s of lac tic bac
teria on the pro duction rate o f rotifers, Brachionus plicat i-
lis, and their dietary value for larval turbot Scopthalmus
maximus. Aquaculture96, 335-342.
Genodepa J., Southgate P.C. & Zeng C. (2004) Diet particle
size preference and optimal ration for mud crab, Scylla
serrata, larvae fed microbound diets. Aqua culture 230,
493-505.
Hamasak i K. &Hatai K. (1993 a) Experimental infection in
the eggs and larvae of the swimming crabPortunus tritu rbiculatusand th e mud crab Scylla seiratawith seven fun
gal strains belonging to Lagenidiales. Bu lletin o f the
Japanese Soc iety o f Scient ific Fish eries 59,1059-1066.
Flamasa ki K. & Hatai K. (1993 b) Preventio n of fung al infec
tion in the eggs and larvae of the sw imming crab Portunus
trituberculatus and the mud crab Scylla serrata by bath
treatmen t with formalin.Bul letin o f the Japanese Society of
Scientific Fisheries59,1067-1072.
Hamasaki K., Suprayudi M.A. & Takeuchi T. (2002) Mass
mortality during metamorphosis to megalops in the seed
pr od uc tio n of m ud cra b Scylla serrata (Crustacea, Deca
pod a, Portu nidae ). Fisherie s Science 6 8 ,1226-1231.
Heasman M.P. & Fielder D.R. (1983) Laboratory spawning
and mass larval rearing of the mangrove crab Scylla ser-
rata(Forsskl), from first zoea to firs t crab stage. Aqua cul-
ture 34,303-316.
Howell B.R., Day O.J., Ellis T. & Baynes S.M. (1998) Early
stages of farmed fish. In: The Biology of Farmed Fish (ed.
by K.D. Bla ck & A.D. Picker ing) , Sheffield A cad emi c Press,
Sheffield, UK, 415 pp.
Jun g S.H., KimJ.W., Jeon LG. & LeeY.H. (2001) For malde hyde
residues in formalin-treated olive flounder (Paralichthys
olivaceus),black rockfish (Sebastes schlegeli),and seawater.
Aqu acu ltur e194,253-262.
Keenan C.P (1999a) Aquaculture of the mud crab, genus
Scylla past, present and future. In: Mu d Crab Aquacu ltur e
and Biology, Proceedings of an International Scientific For-um, Darwin, Australia, 2124 April 1997, AC1AR Proceed-
ings No. 78(ed. by C.P. Keenan & A. Blackshaw), pp. 9-13.
Australian Centre for International Agricultural
Research, Canberra, Australia.
Keenan C.P. (1999b) The fourth species of Scylla. In: Mu d
Crab Aquaculture and Biology, Proceedings o f an Inter na-
tional Scientific Forum, Darwin, Australia, 2124 April
1997, ACIAR Proceedings No. 78 (ed. by C.P. Keenan & A.
Blackshaw), pp. 48-58. Australian Centre for Interna
tional Ag ricultural Research, Canberra , Australia.
Ke ena n C.P., Davie P.J.F. & M an n D.L. (1998) A rev ision of th e
genus Scyllade Haan, 1833 (Cru stace a: Decapoda: Brach-
chyura: Portunidae). The Raffles Bulle tin o f Zoology 46,
217-245.
Lawre nce A.L. & Lee P.G. (1997) Re sear ch in th e America s.In: Crustacean Nutrition (ed. by L. DAbramo, D. Conklin
& D. Akiyama), pp. 566-587. World Aq uac ult ure Society,
Baton Rouge, LA, USA.
Liong P.C. (1992) The fattening and culture of mud crab
(Scylla serrata) in Malaysia. In: Report of t he Sem ina r on
the Mu d Crab Culture andTrade (BOBP/RE P/51, Bay o f Ben-
gal Programme, Madras, India),Surat Thani,Thailand, 5-8
Nov em ber 1991 (ed. by C.A. Ange li), p p. 1 85- 190 .
Makrid is P. & Olsen Y. (1999) Pro tein d eplet ion of th e ro tifer
Brachionus plica tilis during starvation. Aqu acul ture 174,
343-353.
Man n D. (2001) The influence of microbiology on th e suc
cess of mud crab larval culture, In: Mud Crab Rearing,
Ecology and Fisheries, Book of Abs tracts of 20 01 Work-shop,Can Tho University, Vietnam, 8-10 January 2001
(ed. by L. Le Vay, P Sorgeloos, M. Wille, T.T. Nghia & VN.
Ut), pp. 18-21. Instit ute for Marine Aqu acu ltur e (IMA) -
CanTho University, CanTho City Vietnam.
Ma nn D., AsakawaT. & Pizzuto M. (1999) Developmen t of a
hatch ery system for larvae of the mud crab Scylla serrata
at the Bribie Island Aquaculture Research Center. In:Mud
Crab Aquaculture and Biology, Proceedings of an Interna-
tional Scientific Forum, Darwin, Australia, 2124 April
1997, ACIAR Proceedings No. 78 (ed. by C.P. Keenan & A.
Blackshaw), p. 153-158. Australian Centre for Interna
tional Agricu ltural Research, Canberra, Australia.
Mann D.L., AsakawaT., Pizzuto M., Keenan C.P. & BrockI.J.
(2001) Investigation of an Artem/a-based diet for larvae of
the mud crab Scylla serrata. Asian Fisheries Science 14,175-184.
Me unp ol O., Lopinyos iri K. & Me nas veta P. (2003) The
effects of ozone and probiotics on th e su rvival of black
tiger shrimp (Penaeus monodon). Aquaculture 220,
437-448.
Ng hi a T.T. (2004) Optimization of mu d crab (Scylla paramamo-
sain) larv icul ture in Vie tnam.PhD thesis, Faculty of Agri
cultural and Applied Biological Sciences, Ghent
University, Belgium, 192pp.
1552 2007 The Authors
Jour nal Compilation 2007 Blackwell Publishing Ltd, Aqu acu ltu re Research, 38, 1539-1553
http://wwiv.fao.org/docrep/http://wwiv.fao.org/docrep/ -
7/26/2019 kepiting (2)
15/15
Aquac ulture Research, 2007, 38, 1539-1553 Improved rear ing tech niq ues for mud crab larvae T T Nghia et al.
Quillere I., Marie D., Roux L., Gosse F. & Morot-Gaudry J.F.
(1993) An artificial p roductive ecosystem based on a fish:
bacte ria : pl an t ass oci ation. 1. Design an d mana gemen t.Agriculture E cosyste ms a nd Environmen t47,13-30.
Qu initi o E.T., Parad o-E step a F., Milla men a O.M., Rodrig uez E.
& Borlongan E. (2001) Seed produc tion of mud crab Scylla
serra tajuveniles. Asi an Fisheries Science14,161-174.
Quinitio E.T. & Parado-Estapa F.D. (2003) Biology and
hatcher y of mu d crabs. Scyll a spp. SEAFDEC. Tigbauan,
Philippines, 42pp.
Rattanachote A. & Dangwatanakul R. (1992) Mud crab
{Scylla serrataForsskl) fattening in Surat Thani province.
In: Report o f the S em ina ron the M ud Crab Culture andTrade
(BOBP/REP/51, Bay of Bengal Programme, Madras, India),
Surat Thani, Thailand, 5-8 November, 1991 (ed. by C.A.
Angeli), pp. 1 71-177.
Rom baut G., Sua ntika G., Boon N., Maertens S., Dhert P.,Top
E., Sorgeloos P. & Verstraete W. (2001) Monitoring of the
evolving diversity of the m icrobial comm unity present in
rotifer culture. Aquacul ture 198,237-252.
Shelbourne J.E. (1964) The artificial propagation of marine
fish. Advances in M arin e Biology 2,1-83.
Shelley C. & Field D. (1999) The culture of Portunid crabs.
Infofi sh In ter nat ion al4 ,46-49.
Sokal R.R. & Rohlf F.J. (1995) Biometry: The Principles and
Practice o f Sta tis tic s in Biological Research, 3rd edn.
W.H. Fre em an an d C ompany, N ew York, NY, USA, 887pp.
Sorgeloos P. & Lavens P. (1996) Manua l on the Production and
Use o f Live Food fo r Aquacul ture. Fisheries Technical Paper,
Vol. 361. Food and A gric ultu re Organ ization of the United
Na tio n, Rome , I tal y pp . 9-1 00 .
Sorgeloos P. & Lger P. (1992) Improved l arvicul ture ou tputsof marine fish, shrimp and prawn. Journal o f the World
Aqu acu ltur e Soc iety23,251-264.
Suprayudi M., Takeuchi T., Hamasaki K. & Hirokawa J.
(2002) Effect ofAr tem ia feeding schedule and density on
the survival and development of larval mud crab Scylla
serrata . Fisheries Sc ience 68,1295-1308.
Tango M.S. & Gagnon G.A. (2003) Impact of ozonation on
water quality in marine recirculation systems. Aquacul
tural Engineering 29 ,125-137.
Tend encia E. A. & de la Pea M. (2003) Investiga tion of some
components of the greenwater system which makes it
effective in the in itia l control of lumin ous bacteria. Aqua-culture 218,115-119.
Tseng K.F., Hua ng J.S. & Liao LC. (1991) Species con trol of mi
croalgae in an aquaculture pond. Water Research 25,
1431-1437.
Tw arow ska J.G., W es ter m an RW. & Losor do T.M. (1997)
Water treatment an d waste characterization evaluation
of intensive recirculating fish production system. Aqua-
culture Engineering16 ,133-147.
Van Stapp en G. (1996) Arte mia .In: Manual on the Product ion
and Use of Live Food for Aquaculture. FAO Technical Paper
No. 361 (ed. by P. Lav en s & E Sorgeloos), pp. 101-170 . Food
and Agriculture Organization of the United Nation,
Rome, Italy.
VASEP. (2003) Japan ban ned on using form alin in aq uacul
ture (in Vietnamese). Magaz ine o f Vietnam Assoc iation of
Seafood Exporters and Producers,May 2003.
Wang J.K. (2003) Conceptual design of a microalgae-based
recirculating oyster and shrimp system. Aquacul tura l
Engine ering28 ,37-46.
Xuan T.T. (2001) The status and the prospect of mudcrab
culture in Ca Mau province, Vietnam. In: Mud Crab
Rearing, Ecology an d Fisheries, Book of Abs tracts of
2001 Workshop, Can Tho University, Vietnam, 8-10
January 2001 (ed. by L. Le Vay, P. Sorgeloos, M. Wille,
T.T. Nghia & VN. Ut), p. 28. Institute for Marine Aqua
cu ltu re (LMA) - C an T ho University, Can Tho City,
Vietnam.
Zeng C. & Li S. (1999) Effects of density and different combi
nations o f diets on survival, development, dry weight andchemical composition of larvae of the mud crab Scylla
param amosain . In: M ud Crab Aqua cultu re and Biology,
Proceedings of an Interna tional Scien tific Forum, Darwin,
Australia, 21-24 April 1997, ACIAR Proceedings No. 78
(ed. by C.P. Keenan & A. Blackshaw), pp. 159-166. Austra
lian Centre for International Agricultural Research,
Canberra, Australia.
2007 The AuthorsJournal Compilation 2007 Blackwell Publishing Ltd, Aq ua cu ltu re Rese arch . 38, 1539-1553 1553