MARINE PHYTOPLANKTON COMMUNITY STRUCTURE …psasir.upm.edu.my/12425/1/FS_2009_34A.pdf · feed for zooplankton ... dalam sistem kultur ... examination of Mohd Rozhan Bin Zakaria on

UNIVERSITI PUTRA MALAYSIA

EFFECT OF WATER QUALITY AND MARINE PHYTOPLANKTON COMMUNITY STRUCTURE ON SHRIMP PRODUCTION IN TROPICAL

PONDS

MOHD ROZHAN BIN ZAKARIA FS 2009 34

EFFECT OF WATER QUALITY AND MARINE PHYTOPLANKTON

COMMUNITY STRUCTURE ON SHRIMP PRODUCTION IN TROPICAL

PONDS

By

MOHD ROZHAN BIN ZAKARIA

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfilment of the Requirements for the Degree of

Master of Science

June 2009

ii

DEDICATION

This piece of work is dedicated to my wife and daughter, Rozaini and Raihana, my

parents and the rest of my family members for their love, enthusiasm and

inspiration…

iii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment

of the requirement for the degree of Master of Science

EFFECT OF WATER QUALITY AND MARINE PHYTOPLANKTON

COMMUNITY STRUCTURE ON SHRIMP PRODUCTION IN TROPICAL

PONDS

By


June 2009

Chairman: Fatimah Md. Yusoff, PhD

Faculty: Science

Production of giant black tiger shrimp (Penaeus monodon) in earthen ponds in the

tropical region may vary as the pond matures, depending on water quality and

phytoplankton community structure. The objectives of the present study were to

determine water quality and marine phytoplankton succession in ponds of different

ages, to nutritional value of isolated species of a dominant cyanobacterium in the

shrimp ponds in comparison with a beneficial diatom and green alga and to

investigate how phytoplankton community structure could be affected by alteration

of macronutrient concentrations in mixed cultures. The field study was carried out in

an intensive shrimp farm in Kuala Selangor, Malaysia. Phytoplankton and water

samples were collected from ponds of different ages categorized as new (<1yr),

intermediate (2-5yrs) and old (>10yrs), for 16 weeks of shrimp culture. Fluctuation

of nutrient and chlorophyll-a concentrations were not different from other tropical

iv

shrimp ponds in the region. Cyanobacteria (five genera), diatoms (24 genera),

dinoflagellates (four genera) and green algae (three genera) were four dominant

groups of phytoplankton found in all the shrimp ponds. Diatoms were dominant

during the early stage of the culture in new ponds whilst blue–green algae dominated

intermediate and old ponds throughout the culture period. Shrimp production in new

ponds were significantly higher than intermediate and old ponds (p<0.05) probably

due to the abundance of diatoms at the beginning of the culture cycle, suitable as live

feed for zooplankton and shrimp larvae. Pseudanabaena tenuis was found abundant

in all pond categories throughout the culture period. The cyanobacterium was

isolated for surface structure and proximate analysis in the laboratory. Result showed

that P. tenuis have lower nutritional value in comparison with a common diatom

(Chaetoceros calcitrans) and a green alga (Chlorella pyrenoidosa), indicating that is

was not part of consumable algae among grazers. All the above microalgae species

were used in the nutrient enrichment bioassays in the laboratory to determine the

growth and competition among species when grown singly and in mixed cultures.

The result showed that the diatom grew well in single cultures and competed

successfully over other microalgae in mixed cultures when silica concentrations

increased whilst other essential growth nutrients were not limited. This present

research gives an idea of how shrimp production in ponds of different ages could be

affected by water quality and phytoplankton community structure and how alteration

of nutrient concentrations could be use to stimulate growth of beneficial algae and

suppress harmful algae in mixed culture systems which need further research for

better understandings.

v

Abstrak tesis yang dikemukakan kepada senat Universiti Putra Malaysia sebagai memenuhi

keperluan untuk ijazah Master Sains

KESAN KUALITI AIR DAN STRUKTUR KOMUNITI FITOPLANKTON MARIN

KE ATAS PENGELUARAN UDANG DALAM KOLAM TROPIKA

Oleh


Jun 2009

Pengerusi: Fatimah Md. Yusoff, PhD

Fakulti: Sains

Penghasilan udang harimau (Penaeus monodon) dari kolam-kolam tanah di kawasan

tropika mungkin berbeza dengan peningkatan umur kolam, bergantung kepada

kualiti air dan struktur komuniti fitoplankton. Objektif kajian ini adalah untuk

menentukan kualiti air dan struktur fitoplankton marin pada kolam-kolam udang

berlainan umur, mengkaji struktur permukaan serta analisis proksimat spesis

sianobakteria dominan dalam kolam udang dengan membuat perbandingan ke atas

sejenis diatom dan alga hijau bermanfaat serta mengkaji bagaimana pengubahsuaian

kepekatan nutrien boleh memberi kesan ke atas struktur komuniti fitoplankton dalam

kultur campuran. Kajian lapangan telah dijalankan di sebuah ladang ternakan udang

di Kuala Selangor, Malaysia. Sampel air dan fitoplankton telah diambil dari kolam-

kolam pelbagai peringkat umur yang dikategorikan sebagai kolam baru (< 1 tahun),

vi

kolam pertengahan (2-5 tahun) dan kolam lama (>10 tahun) selama 16 minggu masa

penternakan. Fluktuasi kepekatan nutrien dan klorofil-a tidak berbeza dari ladang

ternakan udang lain. Sianobakteria (lima genera), diatom (24 genera), dinoflagelat

(empat genera) dan alga hijau (tiga genera), merupakan empat kumpulan besar

fitoplankton yang terdapat dalam kolam-kolam tersebut. Diatom merupakan

kumpulan dominan dalam kolam baru semasa peringkat awal penternakan udang

sementara alga biru hijau adalah dominan di dalam kolam pertengahan dan kolam

lama sepanjang tempoh penternakan. Penghasilan udang dalam kolam baru adalah

lebih tinggi dengan perbezaan yang nyata (p<0.05) berbanding kolam pertengahan

dan kolam lama, yang berkemungkinan disebabkan oleh kelimpahan diatom yang

sesuai sebagai makanan hidup untuk zooplankton dan larva udang semasa peringkat

awal penternakan. Pseudanabaena tenuis didapati mempunyai kelimpahan yang

tinggi dalam setiap kategori kolam sepanjang tempoh penternakan. Sianobakterium

tersebut telah dipencilkan untuk kajian struktur permukaan dan analisis proksimat di

dalam makmal. Keputusan mendapati bahawa P. tenuis mempunyai nilai nutrisi yang

rendah jika dibandingkan dengan sejenis diatom (Chaetoceros calcitrans) dan alga

hijau (Chlorella pyrenoidosa) di mana ianya menunjukan bahawa sianobakterium

tersebut bukanlah pilihan sebagai makanan hidup di kalangan peragut. Kesemua

spesies mikroalga tersebut telah digunakan untuk bioesei nutrien di dalam makmal

untuk mengetahui pertumbuhan dan persaingan setiap spesies apabila dikultur secara

berasingan dan di dalam kultur campuran. Keputusan menunjukan bahawa diatom

tersebut mempunyai pertumbuhan yang baik serta mampu mengatasi spesis

mikroalga lain dengan peningkatan kepekatan silika sementara kepekatan nutrien lain

yang penting untuk pertunbuhan adalah tanpa had. Penyelidikan terkini ini telah

menyumbang kepada idea bagaimana kualiti air dan struktur komuniti fitoplankton

vii

boleh memberi kesan ke atas penghasilan udang dalam kolam yang berlainan

peringkat umur. Penyelidikan ini juga membolehkan kita mengetahui bagaimana

pengubahsuaian kepekatan nutrien boleh meningkatkan pertumbuhan alga yang

berguna di samping mengurangkan pertumbuhan alga yang tidak dikehendaki di

dalam sistem kultur campuran yang memerlukan kajian lebih lanjut untuk

pemahaman yang lebih berkesan.

viii

AKCNOWLEDGEMENTS

My deepest appreciation and thanks go to the Chairperson of my supervisory

committee, Professor Fatimah Md. Yusoff who provided me most of my needs

throughout the whole study. I am very grateful and pleased to be working under her

guidance. I have learned a lot from her constructive criticisms, and encouragement,

and I am grateful for the financial support, and individual understanding. Not only I

have reached towards the end of this piece of work, but her support and guidance is

well maintained along the path in the beginning of my career as an academic staff of

UPM.

I am grateful to be provided with excellent expertise and valuable suggestions from

my supervisory committee members, Professor Dr. Suhaila Mohamed and Professor

Dr. Fauziah Othman. I hope that this cooperation will always continue in

accomplishing future research and projects.

My special thanks are dedicated to Dr. Sanjoy Banerjee, Dr. Hamid Rezai, Mr.

Perumal Kuppan, Mrs. Noraini Mohd Ain, Ms. Azilah Jalil and Mrs. Noormawaty

for their technical support and guidance during sample processing, image analyzing

and taxonomic study. Not to forget a very unique appreciation goes to Professor

Shariff Mohamed Din in providing me equipment and facilities throughout my whole

study. Not to forget my dearest friends (Jamal, Natrah, Hazel, Dr. Helena, Prabath,

Dr. Omid, Liza, Jimmy, Zafri, Kamil, Murni, Zarirah, Dr. Ina Salwany, Dr. Syed, Siti

Anarita, Azreen, Siti Zubaidah and many more) and family who never stops

encouraging me for the best in my life.

ix

I certify that an Examination committee met on 16th

June 2009 to conduct the final

examination of Mohd Rozhan Bin Zakaria on his degree thesis entitled ‘Marine

Phytoplankton Community Structure of Tropical Shrimp Ponds’ in accordance with

Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian

Malaysia (Higher Degree) Regulations 1981. The committee recommends that the

candidate be awarded the Master of Science.

Members of Examination Committee are also as follows:

Aziz Arshad, PhD

Associate Professor

Faculty of Agriculture

Universiti Putra Malaysia

(Chairman)

Siti Khalijah Daud, PhD

Associate Professor

Faculty of Science


(Internal Examiner)

Mustafa Kamal Abd. Satar, PhD

Faculty of Agriculture


(Internal Examiner)

Ann Anton, PhD

Professor

Biotechnology Research Institute

Universiti Malaysia Sabah

Malaysia

(External Examiner)

_________________________

BUJANG KIM HUAT (Ph. D)

Professor/ Deputy Dean

School of Graduate Studies


Date:

x

This thesis submitted to the Senate of Universiti Putra Malaysia has been accepted as

fulfilment of the requirements for the degree of Masters of Science. The members of

the Supervisory Committee were as follows:

Fatimah Md. Yusoff, PhD

Professor

Faculty of Science


(Chairperson)

Suhaila Mohamed, PhD

Professor

Faculty of Food Science and Technology


(Member)

Fauziah Othman, PhD

Professor

Faculty of Medicine and Health Sciences


(Member)

__________________________________

HASANAH MOHD. GHAZALI, (PhD)

Professor and Dean

School of Graduate Studies


Date: 16 October 2009

xi

DECLARATION

I declare that the thesis is my original work except for quotations and citations which

have been duly acknowledged. I also declare that it has not been previously, and is

not concurrently, submitted for any other degree at Universiti Putra Malaysia or at

any other institution.

____________________________


Date:

xii

TABLE OF CONTENTS

Page DEDICATION ii

ABSTRACT iii

ABSTRAK v

ACKNOWLEDGEMENTS viii

APPROVAL SHEETS ix

DECLARATION FORMS xi

LIST OF TABLES xiv

LIST OF FIGURES xvi

LIST OF ABBREVIATIONS xxi

CHAPTER

1

2

INTRODUCTION

LITERATURE REVIEW 2.1 Phytoplankton in the Shrimp Pond Environment

2.2 Characteristics of Aquaculture Ponds of Different Age

2.3 Role of Physico-Chemical Factors on Phytoplankton

Succession in Shrimp Ponds

2.3.1 Temperature

2.3.2 Salinity

2.3.3 pH

2.3.4 Dissolved Oxygen

2.3.5 Specific Conductivity

2.3.6 Water Transparency

2.3.7 Total Ammonia-Nitrogen (TAN)

2.3.8 Nitrate+Nitrite-Nitrogen

2.3.9 Phosphorus

2.3.10 Dissolved Silica

2.4 Image Analysis of Microalgae

2.5 Nutritional Value of Microalgae

2.6 Phytoplankton Competition and Succession in Mixed Culture

2.7 Effects of Silica Enrichment on Diatom Growth and

Succession

1

8

8

11

13

15

16

16

17

17

18

18

19

20

22

23

23

25

28

xiii

3

4

5

6

WATER QUALITY AND PHYTOPLANKTON

COMMUNITY SUCCESSION IN TROPICAL SHRIMP

PONDS OF DIFFERENT AGES

3.1 Introduction

3.2 Materials and Methods

3.2.1 Study Area

3.2.2 Field Study

3.3.3 Physico-Chemical Analysis

3.2.4 Phytoplankton Sampling, Sedimentation and

Enumeration

3.2.5 Data Analysis

3.3 Results

3.4 Discussion

3.5 Conclusion

SURFACE STRUCTURE AND NUTRITIONAL

PROPERTIES OF SELECTED CULTURED

MICROALGAE SPECIES

4.1 Introduction


4.2.1 Sample Collection

4.2.2 Isolation, Purification and Culture of Microalgae

4.2.3 Image Analysis of the Microalgae Surface Structure

4.2.4 Proximate Analysis

4.2.5 Data Analysis

4.3 Results

4.4 Discussion

4.5 Conclusion

MICROALGAE COMMUNITY SUCCESSION IN A

NUTRIENT ENRICHMENT BIOASSAY

5.1 Introduction


5.2.1 Experiment 1

5.2.2 Experiment 2

5.2.3 Experiment 3

5.2.4 Data Analysis

5.3 Results

5.4 Discussion

5.5 Conclusion

GENERAL DISCUSSION, CONCLUSION AND

RECOMMENDATION FOR FUTURE RESEARCH

31

31

32

32

35

35

42

45

46

74

90

91

91

92

92

93

95

96

99

100

105

109

110

110

112

112

114

116

117

118

137

143

144

REFERENCES 152

APPENDICES 177

BIODATA OF STUDENT 183

LIST OF PUBLICATIONS 184

xiv

LIST OF TABLES

Table Page

3.1

3.2

3.3

3.4

3.5

3.6

3.7

4.1

4.2

Generalized scenario of management regimes in selected test

shrimp ponds in Kuala Selangor shrimp farm

Mean of shrimp production (kg/ha) with standard error for each

pond category after harvesting in one production cycle (four

months study period).

Physical parameters (temperature, salinity, pH, dissolved oxygen,

specific conductivity and water transparency) readings in new,

intermediate and old ponds during the culture cycle.

Concentrations of total ammonia nitrogen=TAN, nitrate+nitrite

nitrogen=NO3+NO2-N, total phosphorus=TP, orthophosphate

phosphorus= PO4-P, dissolved silica=Si and chlorophyll-a=Chl-a

in new, intermediate and old ponds during the culture cycle.

Values are means±standard errors.

Mean total density of the four major groups of phytoplankton in

new, intermediate and old ponds during the culture cycle

(cells mL-1

).

Checklist of phytoplankton genera according to groups found in

new, intermediate and old ponds in Kuala Selangor Shrimp Farm

during one shrimp production cycle. Values represent mean total

density (cells mL-1

)± std error of the mean (n=3).

Number of genera, dominant genus and density (mean±standard

error of the mean) of four identified phytoplankton groups

(Bacillariophyceae, Cyanophyceae, Pyrrophyceae and

Chlorophyceae) in new, intermediate and old aged ponds during

one shrimp production cycle (16 weeks).

General optimum range of physical parameters of environmental

conditions for culturing microalgae

Means±std errors of biochemical composition for

Pseudanabaena tenuis, Chaetoceros calcitrans and Chlorella

pyrenoidosa cultured in Conway medium.

34

46

48

55

63

69

72

94

104

xv

5.1

5.2

5.3

5.4

Maximum specific growth rate (µ day-1

±std error) of


pyrenoidosa achieved during the 14 days of culture. All species

were cultured using natural seawater treated with 0 (-ve control),

15, 20, 25 mg L-1

Si and Conway medium (+ve control).

Means of maximum specific growth rate (µ day-1

±std error) of


pyrenoidosa achieved during the 14 days of culture when grown

singly. All species were cultured using Conway medium treated

with 25 mg L-1

Si.

3 Means of maximum specific growth rate (µ day-1

±std error) of


pyrenoidosa achieved during the 14 days of culture when grown

in mixed cultures with respective combinations. All species were

cultured using Conway medium treated with 25 mg L-1

Si.

Maximum specific growth rate (µ day-1

±std error) of


pyrenoidosa achieved during the 14 days of culture. All species

were cultured using Conway medium treated with 0 (-ve vontrol),

4, 15, 30 and 45 mg L-1

Si.

120

125

130

132

xvi

LIST OF FIGURES

Figure Page

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

Location of Kuala Selangor, Selangor where the study was

carried out.

Randomize counting of: left, every stripe and right for

every second stripe.

Temperature readings in new, intermediate and old ponds

during one shrimp production cycle within the study

period. Bars indicate standard error (±) of the mean, n=9

ponds.

Salinity readings in new, intermediate and old ponds

during one shrimp production cycle within the study

period. Bars indicate standard error (±) of the mean, n=9

ponds.

pH readings in new, intermediate and old ponds during

one shrimp production cycle within the study period. Bars

indicate standard error (±) of the mean, n=9 ponds.

Dissolved oxygen readings in new, intermediate and old

ponds during one shrimp production cycle within the

study period. Bars indicate standard error (±) of the mean,

n=9 ponds.

Specific conductivity readings in new, intermediate and

old ponds during one shrimp production cycle within the


n=9 ponds.

Water transparency readings in new, intermediate and old



n=9 ponds.

Total ammonia nitrogen concentrations in new,

intermediate and old ponds during one shrimp production

cycle within the study period. Bars indicate standard error

(±) of the mean, n=9.

33

44

47

49

50

51

52

53

54

xvii

3.10

3.11

3.12

3.13

3.14

3.15

3.16

3.17

3.18

Nitrate+nitrite nitrogen concentrations in new,



(±) of the mean, n=9 ponds.

Total phosphorus concentrations in new, intermediate and



n=9 ponds.

Orthophosphate-phosphorus concentrations in new,



(±) of the mean, n=9 ponds.

Dissolved silica concentrations in new, intermediate and



n=9 ponds.

Chlorophyll-a concentrations in new, intermediate and old



n=9 ponds.

Mean total density of phytoplankton in new, intermediate

and old ponds in one shrimp production cycle (16 weeks).

Bars indicate standard error (±) of the mean. Superscript

letters indicates significant level at p<0.05.

Growth of four major groups of phytoplankton in new

ponds during 16 weeks of the shrimp culture. Bars

indicate standard error (±) of the phytoplankton mean total

density.

Growth of four major groups of phytoplankton in

intermediate ponds during 16 weeks of the shrimp culture.

Bars indicate standard error (±) of the phytoplankton

mean total density.

Growth of four major groups of phytoplankton in old

ponds during 16 weeks of the shrimp culture. Bars

indicate standard error (±) of the phytoplankton mean total

density.

56

57

58

59

60

61

64

65

66

xviii

4.1

4.2

4.3

5.1

5.2

5.3

5.4

Filaments of Pseudanabaena tenuis viewed as (A) image

under a light microscope (magnification= X 1000) and (B)

scanning electron micrograph (15KV, magnification= X

10000); CW=cross-wall, TC=terminal cell. Note the

single trichome of P. tenuis which forms from single cells

arranged uniserially and attached together at the cross-

wall.

Cell(s) of Chaetoceros calcitrans viewed as (A) image



2200); S=setae, C=cigulum. Note the setae of C.

calcitrans which arises from the corners at the valve edges

and could be seen clearly using a scanning electron

microscope but hardly observed under the light

microscope.

Cell (s) of Chlorella pyrenoidosa viewed as (A) image



3000). Note small green spherical (S) in a single cell of

the alga viewed under the light microscope (arrow) and

the patchy surface observed in the scanning electron

micrograph (arrow).

Growth of Pseudanabaena tenuis, Chlorella pyrenoidosa

and Chaetoceros calcitrans in control treatment (0 mgL-1

Si) after 14 days of culture. All three species were grown

in a mixed culture using natural filtered seawater. Bars

indicate standard error (±) of the mean.


and Chaetoceros calcitrans) in 15 mgL-1

Si treatment after

14 days of culture. All three species were grown in a

mixed culture using natural filtered seawater. Bars



and Chaetoceros calcitrans in 20 mgL-1

Si treatment after






Si treatment after




100

101

102

119

121

122

122

xix

5.5

5.6

5.7

5.8

5.9

5.10

5.11

5.12

Growth of Pseudanabaena tenuis, Chaetoceros calcitrans

and Chlorella pyrenoidosa and in Conway medium (+ve

control) after 14 days of culture. All three species were

grown in a mixed culture using natural filtered seawater.

Bars indicate standard error (±) of the mean.


and Chaetoceros calcitrans during 14 days of culture

using Conway medium. All species were grown singly

(separated cultures). Bars indicate standard error (±) of the

mean.

Growth of Pseudanabaena tenuis and Chaetoceros

calcitrans during 14 days of culture using Conway

medium. Both species were grown in a mixed culture.


Growth of Pseudanabaena tenuis and Chlorella

pyrenoidosa during 14 days of culture using Conway



Growth of Chaetoceros calcitrans and Chlorella

pyrenoidosa during 14 days of culture using Conway




and Chaetoceros calcitrans during 14 days of culture

using Conway medium. All three species were grown in a

mixed culture. Bars indicate standard error (±) of the

mean.


and Chaetoceros calcitrans without silica (negative

control) after 14 days of culture. All three species were

grown in a mixed culture using natural filtered seawater

added with Conway medium nutrient composition. Bars




Si after 14 days of

culture. All three species were grown in a mixed culture

using natural filtered seawater added with Conway

medium nutrient composition. Bars indicate standard error

(±) of the mean.

123

124

126

127

128

129

131

133

xx

5.13

5.14

5.15



Si after 14 days

of culture. All three species were grown in a mixed culture



(±) of the mean.



Si after 14 days




(±) of the mean.



Si after 14 days




(±) of the mean.

134

135

136

xxi

LIST OF ABBREVIATIONS

ANOVA analysis of variance

Chl-a Chlorophyll-a

1DHA docosahexaenoic acid

DO dissolved oxygen

EPA eicosapentaenoic acid

N north

NaNO2 anhydrous sodium nitrite

NH3+

ammonia

NH3-N ammonia-nitrogen

NH4+ ammonium

NO2- nitrite

PL postlarvae

PUFA polyunsaturated fatty acid

rpm rotation per minute

SFA saturated fatty acid

SGR specific growth rate

TAN total ammonia nitrogen

TP total phosphorus

1

CHAPTER 1

INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Intensive marine shrimp farming has steadily increased over the last decades in order

to meet the world’s market demand although the industry has suffered major

problems in sustaining the growth of shrimp aquaculture such as disease outbreak,

environmental degradation and poor management. Marine shrimp, the giant black

tiger prawn, Penaeus monodon has attracted much attention from aquaculturists in

the Asia and Pacific region due to the technological breakthroughs in its life cycle

control (Samocha, 2004), the development of a variety of commercial feeds along

with the establishment of more efficient farming practices and firm market prices and

demand (Kuperan, 1988). However, according to Sampaio et al (as cited in Case,

Lec, Leitao, Anna, Schwamborn, and Junior, 2008), rapid development in the shrimp

aquaculture industry has been accompanied by increasingly controversial debates

over the environmental, social, and economic impacts. In Malaysia, P. monodon

production varies from one farm to the other depending on the pond sediment

quality, water source and application of responsible aquaculture practices (FAO,

1997).

Yusoff et al. (2002) demonstrated that shrimp production was closely related to the

quality of the water used for the shrimp farming. Water quality in shrimp ponds

usually deteriorates with the progressed culture period due to the accumulation of

2

organic matter from excess feed and metabolites. Briggs and Funge-Smith (1994)

reported that only 15% of the feed was converted into fish flesh whilst the rest went

into the water and sediment. Changes in water quality and increased availability of

nutrients affect the phytoplankton composition in shrimp ponds. Phytoplanktons are

microscopic algae which have the ability to float and derive light as the source of

energy to produce their own food. These organisms are the primary producers in the

aquatic environment. It is accepted by pond managers that shrimp production is

better if there is a stable and relatively high abundance of beneficial phytoplankton

species such as diatoms and low in harmful ones such as cyanobacteria and

dinoflagellates (Alonso-Rodriguez and Paez-Osuna, 2003).

Noxious species of blue-green algae like Oscillatoria spp., Pseudanabaena spp. and

Microcystis spp. caused water deterioration and give bad odor to shrimp flesh

(Izaguirre and Taylor, 1998), whilst certain species of dinoflagellates such as

Alexandrium tamarense, has been reported to cause mortality of Penaeus monodon

in Taiwan in 1989 (Huei-Meei et al., 1993). On the other hand, diatom species such

as Chaetoceros calcitrans, and Skeletonema costatum and certain chlorophytes such

as Chlorella sp., Tetraselmis tetrahele, Isochrysis sp. and Nannochloropsis oculata

have long been used as live feeds in aquaculture as they are highly nutritious

especially in long-chain polyunsaturated fatty acids (PUFA’s) (Brown et al., 1989;

Molina Grima et al., 1995; Viron et al., 2000). In semi intensive shrimp farming

system with large ponds, these live feeds are most likely important as a food source

than the meager amount starter feed that the farmers habitually throw into the pond at

the beginning of the rearing cycle (Fujimura, 1991). Therefore, in most aquaculture

system such as marine shrimp ponds, fertilizers are often applied to promote

3

beneficial phytoplankton growth (Alonso-Rodriguez and Paez-Osuna, 2003). This is

accomplished by repeated small amounts of fertilizers that results in an N:P ratio of

20:1 (Boyd and Daniels, 1994). If the nutrients are not consistently supplied,

depression of phytoplankton population will occur and consequently cause slow

growth of the marine shrimp itself (Hunter et al., 1987).

Yusoff et al. (2002) reported that there was a shift from the dominance of beneficial

phytoplankton species at the beginning of culture period, to the noxious species of

cyanobacteria after a month of culture. Species succession in aquatic environments

starts with small flagellates and diatoms, followed by dinoflagellates which are

relatively bigger in size. Cyanobacteria are usually the dominant species at the final

step as they can thrive under stressful conditions for other organisms and when

nitrogen compounds are scarce.

Phytoplankton succession either in the field or experiments such as in mixed cultures

is important as some researchers argue that studying the behavior of phytoplankton

in pure cultures are particularly unnatural since the phytoplankton community is

never wholly monospecific (Fogg and Brenda, 1987). Experiments were done to

determine the interaction, competition and succession between different species of

phytoplankton in a mixed culture towards environmental factors such as temperature,

light intensity and nutrient availability. Harrison and Davis (1979) analyzed factors

influencing species selection outdoor for continuous phytoplankton cultures while

studies by D’ Elia et al. (1979) and Regan and Ivancic (1984) dealt with mixed

cultures under laboratory conditions. However, there is a paucity of information on

growth characteristics, biochemical composition and nutritive value of mixed culture

Documents

MARINE PHYTOPLANKTON COMMUNITY STRUCTURE …psasir.upm.edu.my/12425/1/FS_2009_34A.pdf · feed for zooplankton ... dalam sistem kultur ... examination of Mohd Rozhan Bin Zakaria on