POPULATION BIOLOGY OF THE GREENBACK GREY MULLET, Chelon subviridis (Valenciennes, 1836) IN MERBOK ESTUARY, KEDAH NOR AZIELLA BT MOHD ROSLI UNIVERSITI SAINS MALAYSIA 2012 POPULATION BIOLOGY OF THE GREENBACK GREY MULLET, Chelon subviridis (Valenciennes, 1836) IN MERBOK ESTUARY, KEDAH by NOR AZIELLA BT MOHD ROSLI Thesis submitted in fulfillment of the requirements for the degree of Master of Science DECEMBER 2012 ACKNOWLEDGEMENT Alhamdulillah, special praises to Allah S.W.T for helping me to finish my master research. I sincerely would like to express my special thanks to my supervisor, Dr. Mansor Mat Isa and my co-supervisor, Prof. Alexander Chong Shu Chien for the helpful advice, suggestion, encouragement and guidance throughout this research. I would like to acknowledge the staff of School of Biological Sciences; En. Nazri, En. Bahrim and Uncle Muthu. Without them, the research activities would never have been undertaken. Not forgotten my laboratory mates and those who helped me directly or indirectly, thanks for the assistances and encouragements. Grateful appreciation is extended to the Universiti Sains Malaysia through the Postgraduate Research Grants Scheme 1001/ Pbiologi/ 834096. Lastly, I express my heartfelt gratitude to my family, especially to my grandmother Hasmah Hussain, my mother Rahmoh Deraman and my father Mohd Rosli Abu Bakar for their blessing, support, constant inspiration and encouragement. Thank you very much. ii TABLE OF CONTENTS Content Page ACKNOWLEDGEMENT………………………………………………………. ii TABLE OF CONTENTS………………………………………………………... iii LIST OF TABLES……………………………………………………………….. viii LIST OF FIGURES……………………………………………………………… x LIST OF APPENDICES………………………………………………………… xiii LIST OF PUBLICATION………………………………………………………. xiv LIST OF SYMBOLS AND ABBREVIATIONS……………………………….. xv ABSTRAK………………………………………………………………………... xvii ABSTRACT……………………………………………………………………..... xix CHAPTER 1: GENERAL INTRODUCTION 1.1 General aspect of population biology………………………………….... 1 1.2 General description of Merbok estuary……………………………….... 1 1.3 Activities in Merbok estuary…………………………………………….. 3 1.3.1 Capture fisheries…………………………………………………… 3 1.3.2 Other utilization…………………………………………………..... 3 1.4 Selected species…………………………………………………………..... 3 1.5 Rationales of the study…………………………………………………… 4 1.6 Objectives of the study…………………………………………………… 5 1.7 Significance of the study…………………………………………………. 5 1.8 Outline of the study……………………………………………………..... 6 CHAPTER 2: LITERATURE REVIEW 2.1 Diversity of mullets or Mugilidae……………………………………....... 7 2.2 Fish identification using classical morphometric and meristic…………9 2.2.1 Morphometric technique………………………………………........ 9 2.2.2 Meristic technique…………………………………………………. 10 2.2.3 Taxonomy and morphology of Mugilidae species…………………. 10 iii 2.3 Length-weight relationship, length-length relationship and condition factor…………………………………………………………… 17 2.3.1 Length-weight relationship………………………………………… 17 2.3.2 Length-length relationship…………………………………………. 21 2.3.3 Condition factor…………………………………………………… 21 2.4 Reproductive biology…………………………………………………….. 23 2.4.1 Reproductive strategy …………………………………………….. 24 2.4.2 Reproductive system………………………………………………. 24 2.4.3 Fecundity………………………………………………………….. 25 2.4.4 Gonadal development …………………………………………….. 27 2.4.5 Gonadosomatic index……………………………………………... 27 2.4.6 Length at first maturity……………………………………………. 28 2.5 Growth, mortality and recruitment pattern……………………………. 29 2.5.1 Growth…………………………………………………………….. 29 2.5.2 Powell-Wetherall plot……………………………………………... 30 2.5.3 ELEFAN I…………………………………………………………. 31 2.5.4 Growth performance index………………………………………… 32 2.5.5 Mortality…………………………………………………………… 32 2.5.6 Length at first capture……………………………………………... 33 2.5.7 Recruitment pattern………………………………………………... 34 CHAPTER 3: FISH IDENTIFICATION USING CLASSICAL MORPHOMETRIC AND MERISTIC; SPECIAL EMPHASIS ON THE FIVE MUGILIDAE SPECIES IN MERBOK ESTUARY, KEDAH 3.1 Introduction……………………………………………………………….. 35 3.2 Materials and Methods…………………………………………………… 37 3.2.1 Sampling location………………………………………………….. 37 3.2.2 Morphometric……………………………………………………… 38 3.2.3 Meristic……………………………………………………………. 41 3.2.4 Data Analysis. …………………………………………………….. 43 iv 3.2.4.1 Univariate analysis ……………………………………... 43 3.2.4.2 Multivariate analysis……………………………………... 44 3.3 Results……………………………………………………………………... 46 3.3.1 Classical Morphometric technique……………………………....... 46 3.3.1.1 Descriptive of mean ratio………………………………... 47 3.3.1.2 Analysis of variance (ANOVA)……………………….... 49 3.3.1.3 Principal component analysis (PCA)…………………… 50 3.3.1.4 Discriminant function analysis (DFA)…………………. 55 3.3.2 Meristic technique……………………………………………….... 59 3.3.2.1 Descriptive statistic and ANOVA………………………. 62 3.3.2.2 Principal component analysis (PCA)………………….... 64 3.3.2.3 Discriminant function analysis (DFA)………………….. 64 3.4 Discussion…………………………………………………………………. 68 3.5 Conclusion……………………………………………………………….... 73 CHAPTER 4: LENGTH-WEIGHT RELATIONSHIP, LENGTH - LENGTH RELATIONSHIP AND CONDITION FACTOR OF THE GREENBACK GREY MULLET, Chelon subviridis IN MERBOK ESTUARY, KEDAH 4.1 Introduction………………………………………………………………. 74 4.2 Materials and Methods…………………………………………………... 76 4.2.1 Sampling location………………………………………………….. 76 4.2.2 Length-weight relationship………………………………………… 76 4.2.3 Length-length relationship………………………………………..... 77 4.2.4 Condition factor…………………………………………………..... 77 4.3 Results…………………………………………………………………….. 78 4.3.1 Length-weight relationship………………………………………… 78 4.3.2 Length-length relationship………………………………………..... 78 4.3.3 Condition factor…………………………………………………..... 82 4.4 Discussion…………………………………………………………………. 84 4.5 Conclusion……………………………………………………………….... 86 v CHAPTER 5: PRELIMINARY ASPECTS ON THE REPRODUCTIVE BIOLOGY OF THE GREENBACK GREY MULLET, Chelon subviridis IN MERBOK ESTUARY, KEDAH 5.1 Introduction………………………………………………………………. 87 5.2 Materials and Methods…………………………………………………... 88 5.2.1 Sampling sites……………………………………………………… 88 5.2.2 Gonad maturity stages…………………………………………….. 88 5.2.3 Histological procedure…………………………………………….. 91 5.2.4 Sex ratio and length at first maturity………………………………. 94 5.2.5 Gonadosomatic index (GSI)………………………………………. 94 5.2.6 Estimation of fecundity and egg diameter………………………… 95 5.2.7 Meteorological data……………………………………………….. 95 5.3 Results……………………………………………………………………... 96 5.3.1 Gonad maturity stages……………………………………………... 96 5.3.2 Monthly variation of maturity stages………………………………. 103 5.3.3 Sex ratio and length at first maturity………………………………..107 5.3.4 Gonadosomatic index (GSI)……………………………………….. 109 5.3.5 Estimation of fecundity and egg diameter…………………………. 110 5.4 Discussion…………………………………………………………………. 113 5.5 Conclusion………………………………………………………………… 116 CHAPTER 6: ESTIMATION OF GROWTH, MORTALITY AND RECRUITMENT PATTERN OF THE GREENBACK GREY MULLET, Chelon subviridis IN MERBOK ESTUARY, KEDAH 6.1 Introduction……………………………………………………………….. 117 6.2 Materials and Methods…………………………………………………… 119 6.2.1 Sampling location………………………………………………….. 119 6.2.2 Growth parameters………………………………………………… 119 6.2.2.1 Bhattacharya’s method…………………………………... 119 6.2.2.2 Powell-Wetherall plot……………………………………. 120 6.2.2.3 ELEFAN I……………………………………………….. 120 vi 6.2.3 Growth performance index (Ø’)…………………………………… 123 6.2.4 Mortality estimation………………………………………………...123 6.2.4.1 Length-converted catch curve……………………………. 124 6.2.4.2 Estimation of natural mortality………………………….. 124 6.2.5 Length at first capture ……………………………………………... 124 6.2.6 Recruitment pattern………………………………………………... 125 6.3 Results…………………………………………………………………….. 126 6.3.1 Bhattacharya’s plot………………………………………………… 126 6.3.2 Powell-Wetherall plot……………………………………………… 129 6.3.3 ELEFAN I (K-scan)……………………………………………….. 129 6.3.4 ELEFAN I (Response surface)…………………………………….. 130 6.3.5 ELEFAN 1 (Automatic search)……………………………………. 130 6.3.6 ELEFAN 1 (Von Bertalanffy growth function)…………………… 131 6.3.7 Growth performance index (Ø’)…………………………………… 132 6.3.8 Mortality estimation………………………………………………… 132 6.3.8.1 Length-converted catch curve…………………………….. 133 6.3.8.2 Probability of capture…………………………………….. 133 6.3.8.3 Natural mortality (Pauly’s equation)………………………134 6.3.8.4 Relative yield per recruit and relative biomass per recruit.. 134 6.3.9 Recruitment pattern……………………………………………….. 137 6.4 Discussion………………………………………………………………… 139 6.5 Conclusion………………………………………………………………… 143 CHAPTER 7: GENERAL DISCUSSION……………………………………… 144 CHAPTER 8: GENERAL CONCLUSION AND RECOMMENDATION 8.1 General conclusion……………………………………………………….. 147 8.2 Recommendation…………………………………………………………. 148 REFERENCES…………………………………………………………………... 150 APPENDICES vii LIST OF TABLES List of table Page Table 3.1 Definition of morphometric measurements………………………... 39 Table 3.2 Definition of meristic counts………………………………………. 42 Table 3.3 Summary of mean ratio (%) for morphometric……………………. 48 Table 3.4 Duncan Multiple Range Test for morphometric…………………… 49 Table 3.5 Result of the Principal Component Analysis (PCA)………………. 51 Table 3.6 Final scores for the coefficients of four principal components……. 53 Table 3.7 Value of eigenvalues, percentage of variance, canonical correlation and discriminant function loadings of morphometric data………... 56 Table 3.8 Classification results of individuals from each species according to affinities by the DFA for morphometric data…………………… 58 Table 3.9 Summary table for meristic data of five Mugilidae species……….. 61 Table 3.10 Student Newman Keuls Test for meristic data……………………. 63 Table 3.11 The eigenvalues, % of variance, canonical correlation and discriminant function loadings of meristic data…………………… 65 Table 3.12 Classification results of individuals