UNIVERSITI PUTRA MALAYSIA

ECOLOGICAL STUDIES ON ZOOPLANKTON FROM THE STRAITS OF MALACCA WITH SPECIAL REFERENCE TO COPEPODS

HAMID REZAEI-MARNANI

FSAS 2002 25

ECOLOGICAL STUDIES ON ZOOPLANKTON FROM THE STRAITS OF MALACCA WITH SPECIAL REFERENCE TO COPE PODS

By

HAMID REZAEI-MARNANI

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirement for the Degree of Doctor of Philosophy

November 2002

DEDICATION

***************

To my son Ocean and my wife Elahe/, ***************

To the memory of my late father who can no longer accompany me on these stormy sew;. ***************

He asked, "And what is the Sea to you?"

I answered, "My life's Breath."

The breath of adventure and excitement,

Of challenge and wandering;

Happiness and fulfdment,

Despair and pain;

Of hope and youth,

Patience and yearning.

The breath that God has breathed into my soul, that

I should live with his sea.

Jerome Thomas

ii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Doctor of Philosophy.

ECOLOGICAL STUDIES ON ZOOPLANKTON FROM THE STRAITS OF MALACCA WITH SPECIAL REFERENCE TO COPEPODS

By

HAMID REZAEI-MARNANI

November 2002

Chairperson : Professor Fatimah Md. Yusoff, Ph.D.

Faculty : Science and Environmental Studies

The purpose of this study was to analyze the zooplankton composition and

distribution in relation to spatial and temporal variations in the Straits of Malacca. The

distribution of zooplankton, was determined using samples collected from 1 3 to 20

stations during four oceanographic expeditions along the Straits in different periods

between 1998 to 2000. Monthly zooplankton samples were also collected from two

stations at nearshore and offshore waters off Port Dickson from July 2000 to June

200 1 .

Copepods comprised an average of 71 .3%, 7 1 .2%, 70.9% and 57.9% of the total

zooplankton populations during consecutive cruises and were the main group of

zooplankton during each sampling period. Total zooplankton densities were higher in

the near-coastal area than the offshore area. A spatio-temporal variation of

zooplankton standing crop both in terms of biomass and density was not significant.

Higher mean density estimates of total zooplankton (mean of 1 2,9 1 8 ± 5,635 indo m·3)

and that of adult copepods (mean of 2,927 ± 1 ,085 indo m·3) were recorded during

III

cruise II (pre-SW monsoon) compared to other cruises. However. variation of

copepods was temporally insignificant but spatially significant. Higher zooplankton

densities were obtained at 10-20 m depth stratum than any other depth strata.

Maximum peak of copepod densities collected off Port Dickson waters coincided with

NE and pre-SW monsoons when samples were collected horizontally and vertically,

respectively. Depth and salinity in associations with other factors explained the

distributional patterns of copepods in the studied area.

A total of 1 19 species of pelagic copepods belonging to calanoids (76), cyclopoids

(9), harpacticoids (6) and poecilostomatoids (28) were determined during the course

of the present investigation. Of these, nine species are new records for the Straits of

Malacca. Two characteristic copepod communities in the northern and southern parts

of the Straits were distinguished. The shallow southern part was characterised by

high-density values and low species diversity (H' = 2.967), and the dominance of few

coastal species such as Oithona simplex and Paracalanus parvus. The deeper waters

of the northern part were characterised by low-density values, relatively high species

diversity index (H' = 3 .632).

The heavy metal concentrations in mixed zooplankton were relatively low: ranging

from 1 . 1 9- 1 0 1 3 .70 Jlg gol wet weight for copper, 16.54-235.78 Jlg gol wet weight for

zinc, 3.92-36.08 Jlg gol wet weight for lead and from 0.32-4.09 Jlg gol wet weight for

cadmium. Concentrations of copper and zinc were higher in near-coastal than offshore

areas, whereas those of lead and particularly cadmium were higher in offshore areas.

iv

PERPU STAKAAN NIYEftilTI PUTIlA MALAYSIA

Abstrak tesis yang dikemukakan kepada Senat UniJersltl Putra Malaysia sebagai memenuhi keperluan untuk ijazah Doktor Falsafah.

KAJIAN EKOLOGI KE AT AS ZOOPLANKTON DARI SELAT MELAKA DENGAN RUJUKAN KHAS KEPADA KOPEPOD

Oleh

HAMID REZAEI-MARNANI

November 2002

Pengerusi : Profesor Fatimah Md. Yusoff, Ph.D.

Fakulti : Sains dan Pengajian Alam Sekitar

Tujuan kajian ini adalah untuk menganaiisis komposisi dan taburan zooplankton

mengikut faktor ruang dan masa. Taburan zooplankton telah dianalisis dengan

menggunakan sampel daripada 13-20 stesen yang telah dikumpul melalui empat

ekspedisi oseanografi Selat Melaka dari tahun 1998 hingga 2000. Sampel bulanan

kopepod juga telah dikumpul daripada dua stesen di persisiran dan luar persisiran

perairan Port Dickson sepanjang Julai 2000 hingga Jun 2001.

Secara puratanya kopepod menyumbang sebanyak 7 1.3%, 7 1.2%, 70.9% dan 57.9%

daripada keseluruhan populasi zooplankton dalam ekspedisi tersebut dan merupakan

komponen zooplankton utama dalam setiap tempoh persampelan. Zooplankton

menunjukkan kepadatan yang lebih tinggi di perairan pantai berbanding dengan

kawasan perairan yang jauh dari pantai. Hasilan semasa zooplankton bagi kedua-dua

unit biojisim dan kepadatan menunjukkan variasi tidak nyata dari segi faktor ruang

dan masa.

v

Anggaran min densiti yang lebih tinggi bagi jumlah keseluruhan zooplankton (min

12,9 1 8 ± 5,635 indo m-3) dan kopepod dewasa (min 2,927 ± 1 ,085 indo 0103) telah

direkodkan semasa ekspedisi II (Pra-monsun Barat Daya). Walau bagaimanapun

variasi taburan plankton kopepod didapati tidak menunjukkan perbezaan mengikut

faktor masa tetapi berbeza mengikut faktor mango Kepadatan zooplankton yang tinggi

dijumpai pada kedalaman 1 0-20 01 berbanding lapisan kedalaman yang lain.

Kepadatan tertinggi kopepod yang di sampel secara mendatar dan menegak perairan

Port Dickson didapati bersamaan dengan jangkamasa monsun Timor Laut dan Barat

Daya. Faktor sekitaran seperti kedalaman dan saliniti atau melalui gabungan dengan

faktor lain didapati mencorakkan taburan kopepod di kawasan kajian.

Sejumlah 1 19 spesies kopepod pelagik yang terdiri daripada kalanoid (76), siklopoid

(9), harpaktikoid (6) dan posilostomatoid (28) telah dikenalpasti. Daripada jumlah ini,

sebanyak sembilan spesies adalah rekod barn untuk perairan Selat Melaka. Dua ciri

komuniti kopepod di sektor utara dan selatan selat telah dikenalpasti. Sektor selatan

selat yang cetek telah dicirikan dengan nilai-nilai kepadatan yang tinggi dengan

kepelbagaian spesies yong rendah (H' = 2.967), serta kedominan beberapa spesies

zooplankton air cetek seperti Oithona simplex dan Paracalanus parvus. Perairan yang

lebih dalam di sektor utara dicirikan dengan nilai ketumpatan rendah dan

kepelbagaian spesies yang agak tinggi (H' = 3.632).

Kepekatan logam berat dalam zooplankton adalah secara relatifnya; berjulat 1 . 19-

10 13 .70 �g gol berat basah bagi kuprum, 1 6.54-235.78 �g gol berat basah bagi zinc,

3.92-36.08 �g gol berat basah untuk plumbum dan 0.32-4.09 J.1g gol berat basah bagi

vi

kadmium. Kepekatan kuprum dan zink adalah lebih tinggi di kawasan berhanlpiran

pantai daripada kawasan luar pantai, manakala bagi plumbum dan kadmium nilainya I

adalah lebih tinggi di kawasan luar pantai.

vii

ACKNOWLEDGEMENTS

The contributions of my supervisors, Professors Fatimah Md. YusotT and

Othman Ross and Dr. Aziz Arshad are gratefully acknowledged. Thanks are due to the

crew of RIV KK Mersuji and those of RIV KK Jenahak for their technical and

friendly support and their professionalism during the cruises. Field assistance was

given by S. Zubaidah, A. Othman, F. Alasvandi, P. Kuppan, K. Shams, A. Dadollahi,

A. Moussavi and K.A. Aguol. I am sincerely grateful to Professors A. Kawamura, A.T.

Law, A. Ichikawa and T. Noro for their useful comments and suggestions pertinent to

sampling methods and the manuscript. I am also thankful to the following persons for

their critical comments and for the identification of some the copepod species: Dr. N.

Iwasaki, Dr. S. Ohtsuka, Dr. G.A. Boxshall, Dr. R. Huys, Dr. R. Bottger-Schnack and

Dr. Mulyadi.

I am also indebted to E. Ranai-rad, whose computer assistance made this work

possible. Thanks are also due to N. Somchit for the help on SURFER plots. I am

grateful to P. Roustaian, S. Jahangard, A. Christianus, L. Asgari and S. Sugiyama for

their kind supports and encouragement throughout the course of this research. The

present work was supported by JICA (Japan International Cooperation Agency) funds

through the University of Putra Malaysia, Faculty of Science and Environmental

Studies, Malacca Straits Research and Development Centre (MASDEC), and IRP A

project No 0 1-02-04-01 65 .

viii

I certify that an Examination Committee on 14th November 2002 to conduct the final examination of Hamid Rezaei-Marnani on his Doctor of Philosophy thesis entitled "Ecological Studies on Zooplankton from the Straits of Malacca with Special Reference to Copepods" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 198 1 . The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows:

JAPAR SIDIK BUJANG, Ph.D. Associate Professor, Faculty of Science and Environmental Studies, Universiti Putra Malaysia (Chairman)

FATIMAH MD.YUSOFF, Ph.D. Professor, Faculty of Science and Environmental Studies, Universiti Putra Malaysia (Member)

OTHMAN BIN HAJJ ROSS, Ph.D. Professor, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Member)

AZIZ ARSHAD, Ph.D. Lecturer, Faculty of Science and Environmental Studies. Universiti Putra Malaysia (Member)

TORKEL GISSEL NIELSEN Professor, Department of Marine Ecology, National Environmental Research Institute, Denmark (External Examiner)

AMSHER MOHAMAD RAMADILI, Ph.D. Professor/Deputy Dean School of Graduate Studies Universiti Putra Malaysia

Date: 2 8 NOV 2002

ix

This thesis submitted to the Senate of Universiti Putra Malaysia has been accepted as fulfilment of the requirement for the degree of Philosophy. The members of the Supervisory Committee are as follows:

FATIMAH MD.YUSOFF, Ph.D. Professor, Faculty of Science and Environmental Studies, Universiti Putra Malaysia (Chairperson)

OTHMAN BIN HAJI ROSS, Ph.D. Professor, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Member)

AZIZ ARSHAD, Ph.D. Lecturer, Faculty of Science and Environmental Studies, Universiti Putra Malaysia (Member)

x

AINI IDERIS, Ph.D. Professorl Dean School of Graduate Studies Universiti Putra Malaysia

Date: 9 JAN 2000

DECLARATION

I hereby declare that the thesis based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.

Hamid Rezaei-Marnani

Date: ;2. 'B j';).. J 9..��!t.

xi

TABLE OF CONTENTS

Page

DEDICATION II ABSTRACT III ABSTRAK v ACKNOWLEDGEMENTS Vlll APPROVAL IX DECLARATION Xl LIST OF TABLES xv LIST OF FIGURES XVlll LIST OF PLATES XXI LIST OF ABBREVIATIONS XXII

CHAPTER

I INTRODUCTION 1

Background of the Study 2

Statement of Problems 3

Importance of the Study 4

Objectives of the Study 6

II LITERATURE REVIEW 7

Introduction 7 General Hydrographical Conditions in the Straits of Malacca 7 Variability in Zooplankton 9 Composition and Density of Zooplankton 1 3 Vertical and Horizontal Distribution 1 4 Distribution of Species in Relation to Hydrographic Conditions 1 7 Zooplankton Biomass 1 9 Trophic Structure 22 Indicator Species 25 Heavy Metals in Zooplankton 27

III GENERAL METHODOLOGY 3 1

Zooplankton 3 1 Sampling Techniques 3 1

Laboratory Analysis 33

Biomass Estimates 33

Wet Weight 33

Dry Weight 33

xii

Density Estimates 34

Taxonomic Determinations 35

Trophic Groups of Copepods 36

Analysis of Heavy Metals 36

Sampling Techniques 36

Analytical Procedures 37

Statistical Analysis of Data 37

IV ZOOPLANKTON DISTRIBUTION IN THE STRAITS OF 44 MALACCA

Introduction 44

Materials and Methods 45

Sampling Techniques 45

Study Area 45

Hydrological Measurements 46 Trophic Groups 46

Results 50

Variations of Environmental Parameters 50

Total Zooplankton (First Method of Counting) 50

Zooplankton Biomass (Spatio-Temporal Variations) 50

Biomass at Depth Strata 52

Composition of Total Zooplankton 56

Spatio-Temporal Distribution 59 Near-coastal vs Neritic Waters 63

Total Zooplankton at Depth Strata 63

Copepod Assemblages (Second Method of Counting) 73

Composition 73

Spatio-Temporal Distribution and Community 76 Structure Community Analysis 88

Relationship among Stations 88

Community Differences 92

Associations of Copepod Species 99

Linking to Environmental Parameters 99

Distribution of Copepods at Depth Strata 100 Community Structure at Depth Strata 106 Community Differences at Depth Strata 106 Trophic Groups 107

Indicator Species 114 Discussion 116

V COPEPOD ANNUAL CYCLE IN PORT DICKSON 148 COASTAL WATERS

xiii

Introduction 148

Materials and Methods 149

Study Area 149

Sampling Techniques 149

Hydrological Measurements 151

Laboratory Analysis 151

Results 151

Variations of Environmental Parameters 151

Composition of Copepods 153

Spatio-Temporal Variations 154

Samples Taken by Vertical Tow 155

Samples Taken by Horizontal Tow 155

Zooplankton Biomass 163

Nearshore vs Offshore Densities 166

Community Analysis 167

Community Structure 167 Community Differences 169

Linking to Environmental Parameters 170

Trophic Groups 173

Discussion 173

VI HEAVY METALS Cu, Zn, Pb AND Cd IN ZOOPLANKTON 182

Introduction 182 Materials and Methods 182

Study Area and Sampling Techniques 183 Results 184

Heavy Metals in Zooplankton from the Malacca Straits 184

Spatial Distribution 184

Near-Coastal vs Offshore Waters 184

Relationship among Stations 187

Heavy Metals in Zooplankton from Port Dickson 189

Seasonal Variations 191

Nearshore vs Offshore Concentrations 191

Linking to Environmental Parameters 193

Discussion 193

VII GENERAL DISCUSSION AND CONCLUSION 202

BIBLIOGRAPHY 212

APPENDICES 247

BIODATA OF THE AUTHOR 263

xiv

LIST OF TABLES

Table Page 1 Comparison of zooplankton densities for various systems within the 15

Malaysian coastal waters. 2 Some ecological data for zooplankton species occurring in different 23

oceanic regions of the world. " List of indicator species of water mass in different tropical seas. 27 .) 4 Statistical analyses performed during oceanographic cruises in the 42-43

Straits of Malacca and monthly samplings off Port Dickson waters. 5 Sampling regime of zooplankton during 1st expedition in the Straits 48

of Malacca. 6 Sampling regime of zooplankton during 2nd expedition in the Straits 48

of Malacca. 7 Sampling regime of zooplankton during 3rd expedition in the Straits 49

of Malacca. 8 Sampling regime of zooplankton during 4th expedition in the Straits 49

of Malacca.

9 Mean biomass of total zooplankton during each cruise, and at 55 stations and locations that presented maximum biomass.

1 0 List of observed zooplankton species other than copepods in the 64 Straits of Malacca.

1 1 Stations that presented maximum zooplankton density during 65 different cruises.

1 2 Results of two-way ANOV A based on estimates of zooplankton and 65 copepod densities and zooplankton biomass. Here, the random factor, location (northern, central and southern parts of the Straits) and the fixed factor treatment (cruise I, II, III, IV).

13 Correlation matrices for various biological properties in the Straits. 66

14 List of observed copepod species in the Straits of Malacca 77-80 (including monthly sampling in Port Dickson).

1 5 Number of adult copepod families, genera and species identified. 80

16 Mean density (ind. mol) and relative density (%) of copepod orders 8 1 during each cruise.

1 7 Characterization of adult copepods during different cruises. 8 1

1 8 Characterization of adult copepods in all the combined cruises in 8 1 different parts of the Malacca Straits.

1 9 Results of two-way ANOV A based on densities of adult copepods, 89 copepod orders, species richness and diversity index (Shannon). The random factor is location (northern, central and southern parts of the Straits) and the fixed factor, cruise (I, II, III, IV) (n = 69).

xv

20 Summary of the results of one-way ANOSIM. Value of ANOSIM 97 statistic (R) for global test for differences between groups (north, centre, south) in each matrix during the four cruises in the Straits of Malacca.

21 Results of one-way ANOSIM for differences in adult copepod 97 communities among cruises based on the Bray-Curtis similarity matrix using square root-transformed species density data.

22 Major species, ranked in order of importance, contributing to the 98 average dissimilarities between samples from north-south and centre- south parts in the Malacca Straits during cruise IV, as determined by SIMPER analyses based on forth-root transformed estimates and the Bray-Curtis measure of similarity.

23 Major species, ranked in order of importance, contributing to the 100 average dissimilarities between samples from north-south and centre-south parts in the Malacca Straits during combined cruises, as determined by SIMPER analyses based on forth-root transformed estimates and the Bray-Curtis measure of similarity.

24 Summary of the environmental parameters that best (only six best 102 variable combinations) explain the biotic pattern at each cruise, accompanied by the correlation coefficient obtained (BIO-ENV analysis). Parameters measured .were: water column temperature, salinity, nitrate, ortho-phosphate, ammonium and depth.

25 Vertical density of copepod taxa at various depth strata in combined 105 stations in the north (N), centre (C), and south (S) parts of the Malacca Straits. Only species with a relative density of � 2% of the total density of copepods in a given stratum were considered.

26 Results of the one-way ANOSIM for testing the difference in 114 copepod communities among different depth strata in the Straits of Malacca.

27 Results of two-way ANOV A based on densities of copepod with 1 14 different feeding strategies. The random factor is location (northern, central and southern parts of the Straits) and the fixed factor, treatment (cruise I, II, III, IV) (n = 70).

28 Comparison of zooplankton biomass taken by vertical haul for 122 various tropical coastal systems within the Malaysian waters.

29 Comparison of mixed zooplankton and copepod density for various 136 tropical coastal systems.

30 Number of copepod families, genera and species identified from 161 Port Dickson waters.

31 Maximum and minimum monthly values for the copepods with the 161 APFF, at stations sampled by horizontal and vertical tows.

XVI

., .., -'-

33

34

35

36

37

38

39

40

41

Relationships between mean monthly rainfall and mean copepod 161 densities.

Results of the two-way ANOSIM test for treatment (monsoons) and 170 block effects (nearshore/offshore) based on the Bray-Curtis similarity matrix using square root-transformed species density data.

Summary of the environmental parameters that best (only six best 171 variable combinations) explain the biotic pattern by each sampling method (vertical and horizontal), accompanied by the correlation coefficient obtained (BIO-ENV analysis). Parameters measured were: water column temperature, salinity, nitrate, ortho-phosphate, ammonium, amount of rainfall, water transparency (Secchi disk), heavy metals (including Zn, Cu, Pb and Cd) and wind speed.

Summary of the environmental parameters that best (only six best 172 variable combinations) explain the biotic pattern by each sampling method (vertical and horizontal), accompanied by the correlation coefficient obtained (BIO-ENV analysis). Parameters measured were: water column temperature, salinity, nitrate, ortho-phosphate, ammonium and amount of rainfall.

Comparison of mean monthly zooplankton density taken by vertical 178 haul for various tropical coastal systems.

Results of Mann-Whitney U-test based on estimates of heavy metal 186 concentrations in the Malacca Straits (nt = 4; n2 = 11).

Results of Kruskal-Wallis test based on estimates of heavy metal 187 concentrations in different parts of the Malacca Straits (n = 15).

Spearman Rank-correlation coefficients for Copper, Zinc, lead and 187 Cadmium concentrations from mixed zooplankton.

Results of Mann-Whitney U-test based on estimates of heavy metal 191 concentrations in coastal waters of Port Dickson (nt = 10; n2 = 10).

Concentrations of heavy metals in zooplankton collected from 199 varIOUS sea areas.

XVII

LIST OF FIGURES

Figures Page

Surface water currents of Southeast Asian Seas in April (Wyrtki. 10 1961)

2 Surface water currents of Southeast Asian Seas in August (Wyrtki, 10 1961)

3 Surface water currents of Southeast Asian Seas in October (Wyrtki, 11 1961)

4 Surface water currents of Southeast Asian Seas in December (Wyrtki, 11 1961)

5 Schematic illustration of vertical hauling immediately after the lead 32 reached to the seabed.

6 Figure 6: Location of sampling stations. Stations shown with asterisk 47 (*) were also used for heavy metal analysis. Divisions referred to in the text are as follows: N: north, C: centre, S: south.

7 Distribution of zooplankton biomass (log transformed) during cruise I 53 and II.

8 Distribution of zooplankton biomass (log transformed) during cruise 54 III and IV.

9 Mean (± SE) estimates of zooplankton biomass of combined stations 55 in the northern, central and southern parts of the Straits of Malacca.

10 Vertical distribution of total zooplankton biomass in the northern (a), 57 central (b) and southern (c) parts of the Straits of Malacca.

11 Composition (%) of major zooplankton groups during different cruises 60 in the Straits of Malacca.

12 Dendrograms showing classification of stations during each cruise, 67 comprising zooplankton density data. The distinguished clusters are marked with letters A and B.

13 Mean density of total zooplankton (averages from all stations 68 combined) during various cruises in the Straits of Malacca.

14 Mean density of copepods (averages from all stations combined) 68 during various cruises in the Straits of Malacca.

15 Distribution (log transformed, density) of total zooplankton during 69 cruises I and II.

16 Distribution (log transformed, density) of total zooplankton during 70 cruises III and IV.

17 Vertical distribution of total zooplankton density and the percentage 72 of different groups of zooplankton in the northern (a), central (b) and southern (c) parts of the Straits of Malacca.

xviii

18 Distribution (log transformed density) of adult copepods during 82 cruises I and II.

19 Distribution (log transformed density) of adult copepods during 83 cruises III and IV.

20 Species diversity indices during four cruises in the Straits of Malacca. 85

21 Mean (± SE) estimates of copepod species diversity index (a) and 86 adult copepod density (b) of combined stations in different parts of the Straits of Malacca.

22 Distribution of adult copepods (log transformed density), average for 87 4 cruises.

23 Mean (± SE) density estimates of calanoids (a), cyclopoids (b), 90 harpacticoids (c) and poecilostomatoids (d) in different parts of the Straits of Malacca.

24 Dendrogram of group classification by stations for all combined 91 cruises in the Straits of Malacca. � stations with high densities; B, stations with low (81) or moderate densities (82).

25 Dendrograms and Multidimensional Scaling (MDS) plots of stations 93-94 during cruises. The goodness-of-fit of each bidimensional representation is expressed by the corresponding stress value.

26 Species cluster formation based on Bray-Curtis analysis showing 101 affinities of dominant species (> 2% relative abundance) in combined cruises using group average strategy [cluster A (sub-clusters AI and A2), cluster B (sub-clusters BI, B2)]' The partitioning of coastal-neritic species from near-coastal species could be recognized only by few speCIes.

27 Dendrograms showing associations of dominant species at depth strata 104 (combined stations).

28 Percentage composition of copepod orders at depth strata in different 108 parts of the Straits of Malacca.

29 Vertical distribution of dominant calanoids Paracalanus parvus (a), 109-110 harpacticoids Euterpina acutifrons (b), poecilostomatoids Oncaea media (c) and cyclopoids Oithona simp/ex (d) in terms of relative density.

30 Vertical distribution of the copepods along with corresponding 1 1 2 diversity index (H') at depth strata in different parts of the Straits of Malacca.

31 Percentage composition of copepod trophic groups at depth strata in 113 different parts of the Straits of Malacca.

32 Location of stations during monthly sampling. 150

33 Seasonal variations of temperature (a), salinity (b), rainfall (c) and 156 water transparency (d) in the study area.

xix

34 Seasonal vanatlons of dominant copepod species belonging to 157 different orders taken by vertical tow in combined nearshore and offshore statipns.

35 Seasonal variations of copepod density at sampling stations (a), and in 158 combined nearshore/offshore stations (b) taken by vertical tow.

36 Seasonal variations of copepod density at sampling stations (a), and in 158 combined nearshore/offshore stations (b) taken by horizontal tow.

37 Seasonal variations of rainfall and copepod mean densities taken by 162 vertical (a) and horizontal (b) tows in combined nearshore and offshore stations.

38 Seasonal variations of total zooplankton biomass taken by vertical tow 165 (a), horizontal tow (b) and in combined methods of tows (c) at sampling stations.

39 Seasonal variations of species diversity index (H') at nearshore and 168 offshore stations by horizontal tow (a), vertical tow (b) and in combined stations (c).

40 Distribution of Pb concentrations in mixed zooplankton in the Straits 185 of Malacca.

41 Distribution of Cu concentrations (log transformed) in mixed 186 zooplankton in the Straits of Malacca.

42 Distribution of Zn concentrations in mixed zooplankton in the Straits 188 of Malacca.

43 Distribution of Cd concentrations in mixed zooplankton in the Straits 189 of Malacca.

44 Dendrogram (a) and multidimensional scaling plots (b) of stations 190 based on heavy metal concentrations along the Straits of Malacca. The goodness-of-fit of bidimensional representation is expressed by the corresponding stress value.

45 Seasonal variations of heavy metal concentrations 111 mixed 192 zooplankton at nearshore and offshore stations (ND: not detectable). The vertical bars represent the standard error.

46 Annual mean of heavy metal concentrations in mixed zooplankton at 194 nearshore and offshore stations (n =20).

xx

Plates

1

2

3

LIST OF PLATES

RN Mersuji

NORP AC net with flow-meter attached

Neuston net

xxi

Page

38

38

38

LIST OF ABBREVIATIONS

ANOSIM = Analysis of Similarity

ANOVA = Analysis of Variance

APFF = Annual Plankton Fluctuation Factor

BIO-ENV = Biotic-Environmental

C = Centre

ChI. a = Chlorophyll a

Contr. = Contribution

CR = Cruise

cv = Coefficient of variation

Diss. = Dissimilarity

Dry wt. = Dry weight

HSD = Honestly Significant Difference

indo = Individual

IRPA = Intensified Research in Priority Areas

km = Kilometre

JICA = Japan International Co-operation Agency

Log. = Logarithmic

MAS DEC = Malacca Straits Research and Development Centre

Max. = Maximum

MDS = Multidimensional Scaling

J.l.g = mlcro gram

Min. = Minimum

J.l.m = micro meter

xxii

mg m-3 = milligram per cubic meter

N = North

NO = Not detectable

ng = nano gram

NE = Northeast

NORPAC = North Pacific

p = Probability

PNE = Pre-northeast

PRIMER = Plymouth Routines in Multivariate Ecological Research

PSW = Pre-southwest

RJV = Research vessel

S = South

SD = Standard deviation

SE = Standard Error

SIMPER = Similarity Percentages

Stn. = Station

SW = Southwest

Unid. = Unidentified

vs = Versus

Wet wt. = Wet weight

Zoopl. = Zooplankton

xxiii

CHAPTER I

INTRODUCTION

The Straits of Malacca is partially landlocked and is situated on the Western

Malaysian Peninsula with a total coastline of 1000 km (Chin, 1993; Forbes, 1995).

The Straits is located in the tropical zone and supports a relatively abundant demersal

and pelagic fish and shrimp species (Ooi, 1 990). The Straits provides almost 70% of

the fishing resources for the Peninsular Malaysia (Chua et al., 1997). It is of particular

oceanographic interest due to upwelling processes in One Fathom Bank (Wyrtki,

1961; Uktolseya, 1988). The Straits is deeper in the north and gradually becomes

shallower in the south. The Straits is relatively a narrow channel due to the presence

of shoals, and shallow depths in certain parts such as the eastern end near Singapore;

and this limits its ability to dilute and flush out pollutants.

An understanding of marine planktonic food webs requires information on the

density, biomass and the interactions between all trophic levels. A pre-requisite for

the proper management of the fishery resources of the Straits area is an understanding

of some of the basic biological factors, such as spatial and temporal distributions of

zooplankton in relation to environmental parameters due to their importance as the

major food item of the pelagic fish has been reported (Subrahmanyan, 1 959).

Zooplankton constitute one of the important intermediate steps in the food-chain

pyramid of the coastal waters, as well as open ocean waters and plays a critical role in

the ecology of marine systems by serving as links between phytoplankton and

bacterioplankton, and higher trophic levels such as nekton and benthos.