universiti putra malaysia the role of the...
TRANSCRIPT
UNIVERSITI PUTRA MALAYSIA
THE ROLE OF THE MICROFLORA AND MICROFAUNA COMMUNITIES IN THE PRODUCTION OF UDANG GALAH (Macrobrachium rosenbergii (de Man) JUVENILES USING
THE 'MODIFIED STATIC "GREEN-WATER" SYSTEM'
NG CHEE KIAT
FPSS 1995 1
THE ROLE OF THE MICROFLORA AND MICROFAUNA COMMUNITIES IN THE PRODUCTION OF UDANG GALAH
(Macrobrachium rosenbergii (de Man) JUVENILES USING THE 'MODIFIED STATIC "GREEN-WATER" SYSTEM'
By
NG CHEE I<IAT
Thesis Submitted in Fulfilment of the Requirements for the Degree of
Master of Science in the Faculty of Fisheries and Marine SCience
Universiti Pertanian Malaysia
February 1995
DEDICATION
This work is dedicated to the many researchers in
the country whose works have not been given due recog
nition, for the many hours spent in the laboratory and
in the field to provide the country with solutions to a
better life.
ii
ACKNOWLEDGEMENTS
I would like to express my heartfelt thanks and
appreciation to the many people who have helped in the
course of the preparation of this thesis notably Pro
fessor Dr Ang Kok Jee and Associate Professor Dr
Phillip Arumugam to whom l owe a great deal for the
completion of this thesis.
Also, I would like to express appreciation to Mr
Kenneth Chin, En Ahmad Fawzi, Ms Tan Lay Kean, academic
and non-academic staff at the Faculty of Fisheries and
Marine Science and all who have contributed in one way
or another.
Last but not least, I am deeply indebted to my
parents and my wife who have been very patient and
s4��ortive during the period of my graduate studies.
iii
TABLE OF CONTENTS Page
ACKNOWLEDGEMENT S . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i i
L I ST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi i
L I ST OF F I GURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i x
L I ST OF PLATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
ABS TRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x i
ABSTRAK x i i i
CHAPTER
1 . I NTRODUCT I ON 1
2 . L I TERATURE REVI EW . . . . . . . . . . . . . . . . . . . . 4 Commmuni ty deve l opment and succe s s i onal patterns... . . . . . . . . . . . . . . 4
B i o l og i ca l f actors . . . . . . . . . . . . . . . . . 5 Phys i co- chemi cal factors . . . . . . . . . . . 6 L i ght . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
B i o l o gy o f the Udang Gal ah l arvae . . . . 8 Wat er qua l i ty requ i rement s . . . . . . . . . 8 Food and feed i ng hab i t s . . . . . . . . . . . . 9 Larvae ecol ogy . . . . . . . . . . . . . . . . . . . . . 1 0
The "modi f i ed stat i c " green-wat e r " system ' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Cul ture system . . . . . . . . . . . . . . . . . . . . . 1 1 Funct i on i ng o f the system . . . . . . . . . . 1 2 Al gal removal o f nut r i ents . . . . . . . . . 1 2 " Green-water " chem i s t ry . . . . . . . . . . . . 1 3 B i o l og i cal components o f " Green-wat e r " . . . . . . . . . . . . . . . . . . . . . . 1 5
3 . MATER I ALS AND METHODOLOGy . . . . . . . . . . . 1 7 Exper i menta l des i gn . . . . . . . . . . . . . . . . . 1 7 Larv i cu l ture t e chn i que . . . . . . . . . . . . . . 1 8 S amp l i ng and anal yt i ca l methods . . . . . 1 9
Phys i cal and chemi cal parameters . . 1 9 P l ankton , peri phyton and epi z o i tes 1 9 Larval stag i ng . . . . . . . . . . . . . . . . . . . . 2 0 Data t reatment . . . . . . . . . . . . . . . . . . . . 2 1
iv
CHAPTER
4 . PREL IMI NARY EXPERIMENTS . . . . . . . . . . . . . Mate r i a l s and methodol ogy . . . . . . . . . . . Resul t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Phys i co - chemi cal parameters . . . . . . . B i o l og i cal parameters . . . . . . . . . . . . . C ommuni ty deve l opment . . . . . . . . . . . . . Larval growth rates . . . . . . . . . . . . . . .
D i scuss i on . . . . . . . . . . . . . . . . . . . . . . . . . . Phys i co - che i cal parameters . . . . . . . . Commun i ty devel opment . . . . . . . . . . . . . Larval growth and deve l opment . . . . .
5 . SER I ES ONE . . . . . . . . . . . . . . . . . . . . . . . . . .
Mate r i a l s and methodo l ogy . . . . . . . . . . . Larv i cul ture methods and l i ght t reatments . . . . . . . . . . . . . . . . . . . . . . . . S amp l i ng methods . . . . . . . . . . . . . . . . . . Phys i co - chemi cal parameters . . . . . . .
Resul t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phys i co- chemi cal parameters . . . . . . . C ommuni ty devel opment . . . . . . . . . . . . . Larval g rowth and deve l opment . . . . .
D i scus s i on . . . . . . . . . . . . . . . . . . . . . . . . . . Phys i co - chemi cal parameters . . . . . . . Commun i ty devel opment . . . . . . . . . . . . . Larva l growth and devel opment . . . . .
6 . SER I ES TWO . . . . . . . . . . . . . . . . . . . . . . . . . . Mate r i a l s and methodo l ogy . . . . . . . . . . .
Cul ture method and l i ght t reatments Sampl i ng f requency . . . . . . . . . . . . . . . .
Re sul t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phys i co-chemi cal parameters . . . . . . . L arva l growth and devel opment . . . . .
D i scuss i on . . . . . . . . . . . . . . . . . . . . . . . . . . Phys i co - chemi cal parameters . . . . . . . Larval growth and devel opment . . . . .
7 . SERI ES THREE . . . . . . . . . . . . . . . . . . . . . . . . Mate r i a l s and methodol ogy . . . . . . . . . . .
Exper i mental des i gn and cul ture system . . . . . . . . . . . . . . . . . . . . . . . . . . . . S amp l i ng f requency . . . . . . . . . . . . . . . .
v
Page
2 2 2 2 2 3 2 3 2 3 2 4 2 5 3 1 3 1 3 2 3 8
3 9 39
3 9 4 0 4 0 4 0 4 1 4 1 4 1 4 4 4 4 4 4 45
4 6 4 6 4 6 4 6 4 7 4 7 4 7 4 8 48 4 9
5 1 5 1
5 1 5 1
CHAPTER
Resu l t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Phys i co - chemi cal parameters . . . . . . .
Commun i ty deve l opment . . . . . . . . . . . . .
Ef fect o f l i ght on commun i ty deve 1 opmen t . . . . . . . . . . . . . . . . . . . . . . .
Growth rates o f l arvae . . . . . . . . . . . .
D i scus s i on . . . . . . . . . . . . . . . . . . . . . . . . . .
Phys i co - chemi c a l parameters . . . . . . .
Commun i ty deve l opment . . . . . . . . . . . . .
L arva l growth and devel opment . . . . .
8 . GENERAL D I SCUS S I ON . . . . . . . . . . . . . . . . . .
Phys i co - chemi cal parameters . . . . . . . . .
L i ght i ntens i ty . . . . . . . . . . . . . . . . . . .
T emperature . . . . . . . . . . . . . . . . . . . . . . . pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nut r i ent leve l s . . . . . . . . . . . . . . . . . . .
Communi ty deve l opment . . . . . . . . . . . . . . .
Phyt opl ankton commun i ty . . . . . . . . . . .
Zoopl ankton communi ty . . . . . . . . . . . . .
P e r i phyton commun i ty . . . . . . . . . . . . . .
Epi z o i te communi ty . . . . . . . . . . . . . . . . Bact e r i a l popu l at i ons . . . . . . . . . . . . .
Funct i on i ng o f the system . . . . . . . . .
E f f ect o f di f fe rent l i ght i ntensi t i es . . . . . . . . . . . . . . . . . . . . . . .
L arval g rowt h and devel opment . . . . . . .
9 . SUMMARY AND CONCLUS I ONS . . . . . . . . . . . . .
Conc l us i ons
B I B L I OGRAPHY
APPEND I X
A B C D E
F
" Green-wat e r " product i on . . . . . . . . . . .
Egg custard preparat i on . . . . . . . . . . . .
Ana l yt i ca l methods . . . . . . . . . . . . . . . . .
L arval stages o f devel opment . . . . . . .
M i c ro f l ora and mi c ro f auna popu l at i ons . . . . . . . . . . . . . . . . . . . . . . . .
C o l our p l ates . . . . . . . . . . . . . . . . . . . . . .
vi
Page
52 52 52
53 53 6 1 6 1 6 4 6 5
6 6 6 6 6 6 6 6 6 7 6 7 6 9 6 9 7 0 7 1 7 2 7 2 7 3
7 4 7 6
7 7 7 9
8 2
9 5 9 6 9 7
1 0 0
1 0 1 1 0 3
LIST OF TABLES
T ab l e P age
1 Re l at i ve f requen c i es o f bacter i a recovered f rom cul ture water , cul ture t ank sediment and washed l arvae t i ssue s l ur r i es f rom Ma l ays i an Macrobrach i um rosenbe rgi i hatche r i es . . . . . . . . . . . . . . . . . . . . . . . . . 1 6
2 Amount of l i ght ( k l ux ) rece i ved by cul ture
3
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
1 5
1 6
t anks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5
Mean p H values of cul ture water
Ammoni a l eve l s i n cul ture water
N i t rate l evel s i n cul ture wate r
Phosphate l eve l s i n cul ture water . .
Organi sms found i n " Green-water " . . .
S imi l ari ty i ndex for phytop l ankt on communi ty . . . . . . . . . . . . . . . . . . . . . . . . . .
S imi l ar i ty i ndex for z oop l ankt on communi ty . . . . . . . . . . . . . . . . . . . . . . . . . .
S imi l ar i ty i ndex for peri phyton communi ty . . . . . . . . . . . . . . . . . . . . . . . . . .
S imi l ar i ty i ndex for epi z o i te communi ty . . . . . . . . . . . . . . . . . . . . . . . . . .
Ave rage l i ght i ntens i ty read i ngs . . .
pH l eve l s i n cul ture water . . . . . . . . .
Ammoni a l eve l s i n cul ture wate r on Day 6 • . • • • • • • • • . • • • • • • • • • • • • • • • • • • •
Phosphate l eve l s i n cul ture water . . .
N i t rate l eve l s in cul ture wate r . . . . .
vii
2 6
2 7
2 7
2 7
2 8
3 6
3 6
3 7
3 7
4 2
4 2
4 2
4 3
4 3
Tab l e
1 7
1 8
1 9
2 0
2 1
2 2
2 3
2 4
2 5
2 6
2 7
2 8
2 9
3 0
Dens i ty of prawn l arvae after 7 days
St ages of prawn l arvae after 7 days
Ave rage l i ght i ntens i ty readi ngs . . . .
pH val ue s of cul ture wate r . . . . . . . . . .
Ave rage l i ght i ntens i ty read i ngs . . . .
pH val ues of cul ture wate r . . . . . . . . . .
Phosphate l eve l s i n cul ture water . . .
Ni t rate l eve l s i n cul ture wat e r
Ni t r i t e l eve l s in cul ture wat er
Ammoni a l eve l s i n cul ture wate r
Percentage surv i val of prawn l arvae .
Growth rate of prawn l arvae . . . . . . . . .
Dens i ty of domi nant p l ankton i c groups
Dens i ty of domi nant peri phyton and epi z o i te groups . . . . . . . . . . . . . . . . . . . . .
viii
Page
4 3
4 4
4 7
4 8
5 4
5 4
5 5
5 5
56
56
5 7
5 7
5 8
5 9
LIST OF FIGURES
F i gure Page
1 : Deve l opment of ma j o r phytopl ankton groups over t ime under d i f f erent l i ght
2
3
4
i ntensi t i es . . . . . . . . . . . . . . . . . . . . . . . . 2 9
pH o f water i n cul ture tanks . . . . . . .
Maj or nut r i ent recycl i ng pathway i n the ' modi f i ed stat i c " Green-wat e r " system
T roph i c i nt e r - re l at i onsh i p s for the ' modi f i ed stat i c " Green-wat e r " system
50
6 8
75
5 D i f fe rences i n the e l even ( 1 1 ) l arval stages o f devel opment for Macrobrach i um rosenbe rgi i ( de Man ) as i dent i f i ed by Uno and Kwon ( 1 9 6 9 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0 0
ix
LIST OF PLATES
Plate
1: Experimental design of culture tanks
2: "Green-water"
3: ChIarella sp.
4: Coelastrum sp.
5: Euplotes sp. . . . . . . . . . . . . . . . . . . . . . . .
6: vorticella sp.
7: Brachionus sp.
8: Colurella sp.
9: C�mbella sp.
10: Unidentified periphyton
Page
30
102
102
103
103
104
104
105
105
106
Abs t ract of the s i s submi tted to the Senate of Uni vers i t i Pertan i an Mal ays i a i n ful f i l ment of the requi rement s for the Degree of Master o f S c i ence .
THE ROLE OF THE MICROFLORA AND MICROFAUNA COMMUNITY IN THE PRODUCTION OF UDANG GALAH JUVENILES
USING THE 'MODIFIED STATIC "GREEN-WATER" SYSTEM'
By
NG CHEE KIAT
January 1 9 9 5
Chai rman P ro fessor D r . Ang Kok Jee
The "modi f i ed stat i c " green-wat e r " system ' for t he
produc t i on of udang gal ah j uveni l e s was devel oped by
Ang and Cheah ( 1 9 8 6 ) . However , stud i e s on the mi c rob i -
a l communi ty are scant . The re f o re , expe r i ments were
conducted to study the funct i on i ng of the 'mod i f i ed
stat i c " green-water " system ' wi th respect to the
mi c ro f l ora and m i c ro f auna commun i ty and the e f fect o f
l ight i ntens i ty on the system . Four s e r i e s o f expe r i -
ments were conducted at vari ous l i ght i ntens i t i es t o
study the e f fect of light i nten s i ty o n the system w i th
respect to communi ty s t ructure . Exper i ments were
conducted for the durat i on of the l arv i cul ture per i od
whi ch ranged f rom 2 0 to 25 days . Resul ts were compared
u s i ng Moros i ta ' s i ndex of s imi l ar i ty . Communi ty st ruc-
x i
ture for both the p l ank toni c as we l l as sedentary
commun i t i e s were not seen to be af fected by d i f f e rent
l i ght i ntens i t i es . Change in commun i ty st ructure over
t ime was more evi dent i n p l ank ton i c commun i t i es as
compared wi th the pe r i phyton or epi z o i c commun i t i es .
Chl o re l l a §Q. was found t o be domi nant i n the phyto
pl ank ton commun i ty throughout the exper imental per i od .
I n the epi z o i te commun i ty , Vort i ce l l a §Q. was found
to be domi nant in the f i rst week of cul ture whi l e
c i l i ates were domi nant after the f i rst week . For the
zoopl ank ton commun i ty , the l ater stages be i ng domi nat
ed by the c i l i ate Eupl otes �. and the rot i fer Col ur
el l a §2 . . The dominant g roup i n the peri phyton commun
i ty was the b l ue-green al gae Anacyst i s §Q. and the
di atom Cymbe l l a §Q. whi l e i n the epi z o i t e communi ty ,
Vort i ce l l a §Q. the stal ked c i l i ate was domi nant i n the
ear l y per i od of expe r i ments , fol l owed l ater by Eu
pl otes §Q. and Co l ure l l a §Q . . The phytopl ankton group
appears to be dependent on the domi nant phytopl ank ton
i n the " green-wate r " . P rawn l arvae cul tured i n
the absence o f l i ght d i d not survi ve past the second
week of cul ture . E f fect of the mi c ro f l o ra and mi c ro
fauna commun i ty on the growth and surv i val of the
prawn l arvae was not apparent except at zero l i ght
intens i t y .
x i i
Abs trak tes i s yang d i k emukakan kepada Senat Uni ve r s i t i Pertani an Ma l ays i a sebaga i memenuhi kepe r l uan untuk i j az ah Master Sains
ROL KOMUNITI MIKROFLORA DAN MIKROFAUNA DALAM PENGELUARAN BENIH UDANG GALAH DENGAN CARA 'SISTEM
MODIFlKASI "AIR-HIJAU" STATIK'
O l eh
NG CHEE KIAT
Januari 1 9 9 5
Pengerus i : P ro fe ssor Dr . Ang Kok Jee
S i stem penge l uaran ben i h udang gal ah secara
' s i stem mod i f i kas i " a i r-hi j au " stat i k ' d i maj ukan o l eh
Ang dan Cheah ( 1 9 8 6 ) . Ma l ahan, kaj i an ke at as komuni t i
mi k robe t i dak banyak yang te l ah di j a l ankan . Bebe rapa
kaj i an te l ah di buat untuk memahami l ag i 's i stem mod i -
f i kas i " a i r-hi j au " stat i k ' dari segi komun i t i -komun i t i
m i k ro f l ora dan mi k ro fauna dan j uga kesan kete r i kan
matahari k e atasnya . Empat kaj i an t e l ah di j a l ankan
untuk tuj uan tersebut . Kaj i an di j a l ankan dari masa
t e l ur menetas sehi ngga rega- rega udang men j adi pos t -
l a rva i a i tu s e l ama 2 0 hi ngga 25 hari . Keamat an cahaya
yang berbez a t i dak mengubah s t ruktur komun i t i m i k ro -
f l ora dan mik ro fauna . Keputusan di band i ng dengan
menggunakan i ndeks Moros i ta untok kesamaan . Perubahan
komun i t i mengi kut masa l eb i h nyata dal am komuni t i
xiii
terapung ( pl anktoni c ) dari komuni t i t e r l ekat ( seden
tary and attached ) . Chl o re l l a §Q. d i dapat i domi nan
da l am komuni t i f i topl ank ton untuk sel uruh j angka masa
kaj i an . D a l am komun i t i epi z o i t , Vort i ce l l a §Q. di dapa
ti domi nan pad a mi nggu pertama kaj i an . Dal am komun i t i
z oopl ank ton pada tahap akhi r k a j i an d i dapat i di domi na
si o l eh Eupl otes §Q. dan Colure l l a §Q. Kumpul an yang
dom i nan da l am komun i t i per i f i ton adal ah Anacyst i s ,
se j eni s a l ga j en i s bi ru-hi j au dan Cymbel l a i a i tu
s e j eni s di atom manakal a dal am komun i t i epi z o i t , Vort i
cel l a , se j eni s c i l i at a di dapat i berpengarug pad a t ahap
awal kaj i an dan di i kut i o l eh Eupl otes dan Colure l l a .
Komuni t i f i top l ankton di dapat i d i penga ruhi o l eh j eni s
f i top l ankton yang domi nan semasa tumbesaran " green
wat e r " . Rega udang yang d i pe l i hara da l am tangk i
tanpa cahaya d i dapat i t i dak hi dup l eb i h dar i dua
mi nggu . 'Kesan komun i t i mi k rof l ora dan mi k ro fauna ke
at a s tumbesaran rega udang gal ah t i dak nyata di l i hat
se l a i n dari pada keadaan tanpa cahaya .
xiv
CHAPTER 1
INTRODUCTION
The cul ture of the Gi ant Ma l ays i an Freshwater
Prawn ( Mac robrachi um rosenbergi i t d e Man ) possesses a
great potent i a l for devel opment wor l dwi de ( Rabanalt
1 9 8 2 ; Sand i fe r a l . t 1 9 7 6 ; S i dthimunka and
Bhukaswant 1 9 8 2 ; Suharto et al . t 1 9 8 2 ) . I n Ma l ays i a
because o f i t s h i gh reta i l va l ue o f up t o M$1 6 . 50 per
k i l ogram ( Anont 1 9 8 7 ) as wel l as a hi gh growth rate
( Wi ck i nst 1 9 8 2 ) t the Department of Fi she r i e s has i n
fact earmarked t h i s prawnt a l so known a s t he 'udang
gal ah ' , for deve l opment i n aquacul ture i n the country
( Ongt 1 9 8 4 ) . The proces s i s howeve r s l ow as nat i onw i de
product i on on l y i nc reased by about 1 0 met r i c tonnes i n
two yearst be i ng a t 6 8 met r i c tonne s i n 1 9 8 4 ( Anont
1 9 8 4 ) and 7 8 met r i c tonnes i n 1 9 8 6 ( Anont 1 9 8 6 ) . Thi s
is in part due to inconsistent seed supply accompanied
by a h i gh pr i ce o f pos t - l arvae .
Larvi cul ture of udang ga l ah f i rst achi eved success
wo r l dw i de at the Fi she r i e s Research I n s t i tute i n Penangt
Ma l ays i a ( L i ng and Mer i cant 1 9 6 1 ) .
1
2
Mas s cul ture methods were subsequent ly devel oped by
var i ous workers i nc l ud i ng Fuj i mura ( 1 9 66 ) , Lee ( 1 9 8 2 )
as wel l as Aquacop ( 1 9 8 3 ) . I t has been shown that
product i on of post�l arvae does not d i f f e r very much
between d i f ferent l arv i cul ture systems ( Menasveta and
P i yat i rat i t i vokul , 1 9 8 0 ; Ang et a l . , 1 9 9 0 ; Ang , 1 9 95 ) .
Ang and Cheah ( 1 9 8 6 ) deve l oped a l arvi cul ture
system whi ch al l owed for l es s l abour requi rement s
cal l ed the 'modi f i ed - s t at i c " green-wate r " system ' . Thi s
system works on the p r i nc i p l e that al gae act s as a
remova l agent for tox i c wastes l i ke ammon i a and n i
t r i te , the reby the need for " green-wate r " . Thi s sys t em
has the advantage o f product i on costs as l ow as M$1 0 . 0 0
per 1 0 0 0 j uveni l es ( Ang , pers . comm . ) .
Desp i te the advantages o f the
" g reen-wate r " system ' , very l i t t l e
'modi f i ed stat i c
l i terature i s
ava i l ab l e about the mi c rob i a l ecosystem whi ch i s
present i n the cul ture system . Al so bearing i n mind the
importance of l i ght i n the funct i on i ng of the 'modi f i ed
stat i c " green-water " system ' , the f o l l owing obj ec t i ve s
were s e t f o r thi s thes i s .
3
1 . To study the eco l ogi cal succes s i on o f both the
mi c ro f 1 ora1 and mi c ro f auna1 communi t i es i n the udang
ga1 ah ( Mac robrachium rosenbe rgi i de Man ) 1 a rvi cu 1 ture
tank s and the ro l es they p l ay in the envi ronment .
2 . To det e rmine the e f fect o f l i ght i ntens i ty on
the commun i ty deve l opment i n the 1 arv i cu 1 ture tank and
i t s e f fect on post - l arval product i on of udang ga l ah and
3 . To dete rmine the growth rates of the l arvae o f
the udang ga l ah through anal ys i s o f the devel opmental
stages of the l arvae .
CHAPTER 2
LITERATURE REVIEW
" Green-wate r " a s the term imp l i es , i s water that
i s p redom i nant l y r i ch w i th g reen a l gae of the Order
Chl orophyceae . The ma i n groups of a l gae present in the
"modi f i ed stat i c " green-wat e r " system ' are Chl o re l l a
§2., Scenedesmus §2 . and a l so Chl orococcus §2 . . The
z oopl ankton commun i ty i s be l i eved to be domi nated by
rot i fe r s ( Ang , pers . comm . ) . The method empl oyed i n
product i on o f " green-wate r " i s g i ven i n Appendix A . The
p r i nc i p l e i s a cont inuous add i t i on of nut r i ents togeth
er wi th constant aerat i on in orde r to ensure the wate r
co l umn has suf f i c i ent nut r i ents ava i l abl e for the
cont i nued g rowth of the a l ga l popu l at i ons.
Community development and successional patterns
I n an ecosystem the re wi l l be some spe c i es whi ch
are mo re abundant than othe rs . Thi s i s known as domi
nance and may be due t o phys i ca l , chemi cal o r bi o l og i
cal factors ( Hutchinson , 1 9 6 7 ) . Success i on refers to a
s i tuat i on where there i s a d i rec t i onal change in spe
c i es domi nance . Wa l ke r ( 1 9 8 7 ) cons i ders succes s i on as a
4
5
cont i nuum f rom ear l y s t ages where factors gove rn i ng
co l oni sat i on are most important, to l ate stages whe re
factors governing senescence and mo rt a l i ty predomi nate .
D i sturbance genera l l y prevents the commun i ty reachi ng
the senes cent stage . Reyno l ds et a l . , ( 1 9 8 3 ) used the
term " perturbat i on " for d i sturbance i n p l ankton stud
i e s.
Bio l ogical f actors
B i o l og i cal factors respons i b l e for speci e s domi
nance are usua l l y the resu l t o f spe c i es i nteract i on.
Thi s may be due to compet i t i on amongst spe c i e s for food
and space ( Odum, 1 9 7 1 ) or i t may be due to predat i on o f
one spe c i e s on anothe r ( Rees, 1 9 7 9 ) . Examp l e s of b i o
logi cal l y re l ated succe s s i onal patterns or commun i ty
changes are as reported by Dunn ( 1 9 7 0 ) . B i o l ogi cal
i nteract i ons a l so occur between organi sms f rom d i f fe r
ent communi t i es ( Roeder, 1 9 7 7 ) but are usual l y more
pronounced between t roph i c l eve l s ( B l azka et al . ,
1 9 8 0 ) .
6
Physico-chemical f actors
The ma j o r i ty o f succes s i ona l and commun i ty change
pat t e rns that t ake p l ace i s a resu l t o f phys i co - chemi
cal pa rameters ( Prowse and TaI l i n g , 1 9 5 8 ; Anderson ,
1 9 7 0 ; Hur l be rt et a l . , 1 9 7 2 ; T r i mbee and Harr i s , 1 9 8 4 ;
Ashton , 1 9 8 5 ; ; Gas i th and Perry, 1 9 8 5 ) . The factors
whi ch af fect spe c i es domi nat i on are l i ght , temperature ,
chemi cal s , dens i ty , pressure and sal i n i ty ( Odum , 1 9 7 1 ;
Bo rne f e l d and S imon i s , 1 9 7 4 ) .
Light
L i ght pl ays a very important ro l e in the devel op
ment o f any p l ant commun i ty because o f i t s ro l e i n the
phot osynthet i c p rocess .
Green a l gae was f ound to perform bet ter than di no
f l age l l ates at l ow l i ght i ntens i t i es whi l e d i atoms
pre f e r an i ntermedi ate l i ght i ntens i ty ( Parsons et
a l . , 1 9 8 4b ) . Matthern et a l . , ( 1 9 6 9 ) , Quarai shi and
Spencer ( 1 9 7 1 ) , Bader et a l . ( 1 9 7 6 ) and Young and King
( 1 9 80 ) have a l so demonst rated the e f fect o f l i ght
int en s i ty on a l gae domi nance . Corner and Davi es ( 1 9 7 1 )
7
showed that ammoni a uptake i n the dark was onl y 6 0 % o f
the uptake rate i n l i ght whi l e Duna l i e l l a tert i o l ec t a
( Butche r ) assimi l ated n i t r i te 2 0 t imes f a s t e r i n the
l i ght than i n darkness ( Grant , 1 9 6 7 ) .
Exce ss i ve l i ght can i nh i b i t the growth o f Chl o re l l a
( Fl i k , 1 9 8 5 ) . H i gh l i ght i ntens i t i es can a l so i nc rease
uptake rates o f phosphate ( Kuh1 , 1 9 6 2 ) . Syrett ( 1 9 6 2 )
however showed that there was an i nverse re l a t i onsh i p
between l i ght intens i ty and the chl orophyl l a content .
P l ank ton bl ooms i n the natural envi ronment are
usual l y the resu l t o f favourabl e nut r i ent l eve l s
( Brockmann et a l . , 1 9 7 7 ) . The e f fect o f nut r i ents on
spe c i e s domi nat i on has a l so been shown by Mi ckel son et
al . ( 1 9 79 ) .
Phosphate i s as s i mi l ated by a l gae di rect l y i n the
f orm o f o rthophosphate whi ch can be stored i n the al gae
( Go l t e rman and Kouwe , 1 9 7 4 ) . As a resu l t o f the storage
capabi l i t i e s , the uptake rate o f phosphate i s af fected
by i t s concent rat i on i n the wate r ( Sutt l e and Har r i son ,
1 9 8 6 ) . The uptake o f phosphate can a l so be af fected by
the avai l abi l i ty o f carbon d i ox i de ( Young and K i ng ,
1 9 8 0 ) .
8
Al gae are capab l e o f util ising both ammonia and
nit rate as it s nit rogen source with ammonia being
pre f e rred in most cases ( Mo rris , 1974). This is due to
the fact that ammonia suppresses the synthesis of
nit rate reductase , an enzyme essential for nit rate
util iz ation by al gae ( Stewart , 1980). Some a l gae howev
er exhibit a change in their preference of the nit rogen
source as shown for Chl o re l l a whe re ammonia is pre
ferred in the earlier growth period and nit rate in the
l at e r growth period ( Dvoradkova-Hl adk a , 1971).
Biology of the Udang Galah larvae
Water quality requirements
The l arvae require brackish-water to compl ete its
l a rval stages ( Ling , 1969) cannot survive beyond five
days in f reshwater ( Kurian and Sebastian , 1976). Uno
and Kwon (1969) identified 11 devel opment a l stages o f
the l arvae ( See Appendix F ) f rom the egg til l the post
l arvae stage i . e . , when the l arvae l ose their pl ankto
nic nature . The l arvae is euryhal ine , being ab l e to
withstand g radual changes in s a l inity f rom 3 ppt up to
21 ppt without much p rob l ems ( Fu j imura , 1966).
The i r
3 20C for
1 9 7 6 ) . pH
9
t empe rature t o l e rance i s between 2 40C and
opt imum growth rates ( L i ng and Coste l l o ,
value s between 7 . 0 and 8 . 0 usua l l y do not
present probl ems to the l a rvae ( L i ng and Coste l l o ,
1 9 7 6 ; Kur i an and Sebast i an , 1 9 7 6 ) . Ammoni a tox i c i ty to
the l arvae is repo rted to be at 0 . 6 ppm ( Cohen et al . ,
1 9 7 6 ) whi l e n i t r i te was sub l ethal at 1 . 8 ppm ( Armst rong
et a l . , 1 9 7 6 ) .
Food and feeding habits
Var i ous workers have stud i ed the d i e t s o f prawn
l a rvae espec i al l y us i ng l i ve f eeds ( Anderson and Smi th,
1 9 8 3 ) . The l arvae onl y starts feed i ng after met amorpho
s i s i nto the second zoea or stage I I l arvae ( Choudhury ,
1 9 7 1 ) and feed cont i nuous l y on part i cul ate food as l ong
as i t i s ava i l ab l e ( L i ng , 1 9 6 9 ) . Mol l e r ( 1 9 78 ) showed
that the l arvae wi l l grasp part i c l es of sui t ab l e s i ze
that i t comes i n contact wi th and does not actual l y
have any part i cu l ar preference f o r l i ve food .
The i mportance o f al gae i n the deve l opment o f
crust acean l a rvae has been shown by var i ous wo rkers
( Broad , 1 9 5 7 ; McConnaugha , 1 9 85 ; Fox , 1 9 8 3 ; Sand i f e r ,
1 9 7 2 ) .
10
I n fact , a l gae cu l tures are a key nut r i t i onal
factor in the cul ture o f penae i d l arvae ( L i ao and Chao ,
1983). Cohen et a l . (1976) showed that the l arvae
i ngests neg l i gi b l e amounts o f a l gae . Maddox and Manz i
(1976) however found that al gal suppl ement s added to
l arv i cul ture tank s i mproved growth rates as we l l as
survi vabi l i ty . Wi ck i n s (1972) however suggested that
al gae cou l d get i nto the d i et o f the prawn l arvae
ind i rect ly through the Artemi a naupl i i . Joseph (1977)
suggested that the l arvae may be ab l e to ut i l i z e e ssen
t i a l water so l uble t race compounds f rom the al gal d i et .
The l a rvae has been success ful l y cul tured on food
organi sms such as mi crocrustaceans i n c l ud i ng Moi na sp .
( An i e l l o and S i ngh , 1982) and Artem i a ( B i dd l e , 1977);
minced cock l e ( Anadara granosa ) ( Lee , 1982); f i sh
f l es h , roe o r chi cken egg custard ( Ma l echa , 1983);
squ i d f l esh and worms ( New and S i ngho l k a , 1982).
Larvae ecology
I n nature , the eggs are rel eased near r i ver mouths
or e stuar i es . The eggs on hatching i nto l arvae are
pl ankton i c and tend t o aggregate i n the ea r l i er l arval
stages and are phototact i c in nature ( L i ng , 1969).