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C the SPECIES of RASTRELLIGER in the JAVA SEA, THEIR TAXONOMY, MORPHOMETRY and POPULATION DYNAMICS TATANG SUDJASTANI B.Sc. Acade

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\ c THE SPECIES OF RASTRELLIGER IN THE JAVA SEA, THEIR TAXONOMY, MORPHOMETRY AND POPULATION DYNAMICS by TATANG SUDJASTANI B.Sc. Academy of Agriculture Bogor, Indonesia, 1962 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Zoology We accept this thesis as conforming to the required standard The University of British Columbia April, 1974 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of ZOOLOGY The University of British Columbia Vancouver 8, Canada Date 9 APRIL 1974 ABSTRACT Rastrelliger is a mackerel genus which inhabits the Indo- Pacific Regions. This genus is characterized by long, numerous and featherlike gill rakers, and anal fin without spines. Two species, Rastrelliger braahysoma and R. kanagurta, are recognized. These are identified by the differences in the ratios of the greatest body depth and the length of intestine to fork length, and the appearance of the cephalic lateral line canal systems. Synonymies, descriptions and morphometric ranges are given. The morphometric characters of the two species exhibit some intraspecific differences due to sexual dimorphism and strong allo- metric growth, R. braahysoma exhibits intraspecific geographical variation in its dorsoventral depth, greatest body depth, and inter- orbital distance; while R. kanagurta exhibits variation only in its dorsoventral depth and head depth. Both speci.es attain their maximum growth increments before they reach sexual maturity. The vital parameters for yield prediction are as follows: the coefficient of growth rate K=0.19, 0.23; the length-weight exponent b=2.88, 3.19; the maximum length 1.^=22.92 cm, 23.89 cm; the natural mortality coefficient M=0.38, 0.37; and the total mortality coefficient Z=0.82, 1.20 fori?, braahysoma and R. kanagurta respectively. Rastrelliger fisheries in the Java Sea have not yet ii reached maximum exploitation which suggests the possibility of increas• ing production by increasing fishing intensity. iii TABLE OF CONTENTS Page ABSTRACT i TABLE OF CONTENTS iii LIST OF FIGURES v LIST OF TABLES vii ACKNOWLEDGMENTS ..... x I. INTRODUCTION 1 II. MATERIALS AND METHODS 2 III. RESULTS AND DISCUSSIONS 7 1. Systematics Study 7 Description of the genus Rastrelliger ... 7 Key to the species of Rastrelliger .... 8 Specific Descriptions 8 Rastrelliger braahysoma 8 Rastrelliger kanagurta 9 Nomenclature 12 Diagnostic Characters 23 2. Morphometric Study 25 Sexual Dimorphism 30 Allometrie Growth 30 Geographic Variations . 33 3. Meristic Characters 45 4. Qualitative Characters ........... 49 5. Population Study Rastrelliger Fisheries . Population Parameters . Sexual Conditions .... Longevity Environmental Tolerance Competitor and Predator . Parasites Growth Behaviour Age Length-weight Relationships Recruitment Survival Rates ' Mortalities . Dynamics of Populations . Beverton and Holt Model Ricker Model , IV. GENERAL DISCUSSIONS V. CONCLUSIONS LITERATURE CITED APPENDICES . V LIST OF FIGURES Figure Page 1. Bathymetric Chart of the Java Sea 3 2. Ratio of Body Parts to Fork Length 16 3. Ratio of Fork Length to Body Depth 17 4. Sexual Dimorphisms of Rastvelligev bvachysoma 32 5. Geographical Variations in R. bvachysoma 32 6. Geographical Variations in R. kanaguvta 44 7. First Occurrence of Haemal Brace 47 8. Cephalic Lateral Line Canal System of Rastvelligev . 52 9. Digestive Tracts of Rastvelligev 53 10. Sexual Maturity Stages Composition of R. kanagurta . 61 11. Sexual Maturity Stages Composition of R. bvachysoma . 62 12. Growth Curve of R. bvachysoma 69 13. Growth Curve of R. kanaguvta 70 14. Relation Between Total Effort and Catch Per Unit of Effort of Rastvelligev kanaguvta 75 15. Length Frequency Distribution of R. kanaguvta 86 16. Length Frequency Distribution of R. bvachysoma .... 87 17. Catch Curve of R. kanaguvta 97 18. Catch Curve of R. bvachysoma 98 19. Yield Isopleth Diagrams of R. kanaguvta 106 20. Yield per Recruit as a Function of F of R. kanaguvta; for t = t = 4.0 months 107 21. Yield per Recruit as a Function of F of R. kanaguvta; for t = 4.5 and t = 4.0 months .... 108 vi Figure Page 22. Yield Isopleth Diagrams of R. braahysoma 109 23. Yield per Recruit as a Function of F of R. braahysoma; for t = tp = 3.0 months . 110 24. Yield per Recruit as a Function of F of i?. braahysoma; for t = 4.0 and t = 3.0 months Ill vii LIST OF TABLES Table Page 1. Morphometric Measurements of Rastvelligev bvachysoma 11 2. Morphometric Measurements of R. kanaguvta 13 3. Frequency Distribution of the Ratios of Head- Length to Body Depth 18 4. Frequency Distribution of the Ratios of Fork- Length to Body Depth !9 5. Frequency Distribution of the Ratios of Intestine Length to Fork Length 20 6. Regressions of Sample No. 1 26 7. Regressions of Sample No. 2 27 8. Regressions of Sample No. 3 28 9. Regressions of Sample No. 4 .' . 29 10. Comparisons of Body Proportions Between Males and Females 31 11. Comparisons of Body Proportions Between Class- Modes of 16.0 cm FL and 20.0 cm FL 34 12. Comparisons of Body Proportions Between Class- Modes of 14.0 cm FL and 20.0 cm FL 35 13. Comparisons of Body Proportions Between Class- Modes of 14.0 cm FL and 16.0 cm FL 36 14. Comparisons of Body Proportions Between Samples No. 1 and No. 2 37 vi i i Table Page 15. Comparisons of Body Proportions Between Samples No. 3 and No. 4 . 38 16. Comparisons of Body Proportions Between Samples No. 1 and No. 3 39 17. Comparisons of Body Proportions Between Samples No. 2 and No. 4 40 18. Comparisons of Body Proportions Between Samples No. 2 and No. 3 . 41 19. Comparisons of Body Proportions Between Samples No. 1 and No. 4 42 20. Covariance Analyses for Pairs of Rastrelliger 43 21. Gill Raker Counts of Rastrelliger 48 22. The Degree of Intergradations of the Total Gill Raker Counts of Rastrelliger 48 23. Productions of Payang Fisheries in the North Coast of Java 54 24. Field Key of Maturity Stages (Males) 58 25. Field Key of Maturity Stages (Females) 59 26. Von Bertalanffy Growth Parameters of Rastrelliger from the Indo-Pacific Region 71 27. Age-Length-Weight Key of R. kanagurta 84 28. Age-Length-Weight Key of R. braahysoma 85 29. The Length-Weight Exponential Values of Rastrelliger of the Java Sea 90 ix Table Page 30. The Length-Weight Exponential Values of Rastrelliger from the Indo-Pacific Region 91 31. Survival Rate of R. kanagurta 95 32. Survival Rate of R. braahysoma 96 33. Mortality Coefficients of R. kanagurta 100 34. Ricker Yield Model of R. kanagurta 115 35. Ricker Yield Model of R. braahysoma . 116 36. Ricker Yield Model of R. braahysoma ... 117 X ACKNOWLEDGEMENTS I wish to express my deep appreciation and thanks to my supervisor Dr. Norman J. Wilimovsky who encouraged me to undertake this study, gave advice and criticism. My thanks also goes to Messrs. T.D. lies and Stephen Borden, Dr. D.J. Randall, Dr. J.R. Adams, Messrs. D.E. Wilson, R. Stanley, Ni I-shun and R.S.. Milne for giving useful suggestions. I am very grateful to Messrs. R.B. Wilson, B.J. Anderson and Miss CM. McAskie from the Canadian International Development Agency for contributing in various ways to this study. Finally, I wish to extend my thanks to my superior in the Directorate General of Fisheries, Mr. Moh Unar the Director of the Marine Fisheries Research Institute, and to my colleagues in the Regional Fisheries Services and the Institute for Marine Research in Jakarta for assisting in data collections. i I. INTRODUCTION The Kembung -- the genus Rastrelliger -- constitute one of the most important groups of fishes of the artisanal fisheries of Indonesia. On the north coast of Java in 1971, the catch was 10,000 tons, constituting over 10% of the total marine fisheries production of the area. In the five-years development program of the Government of Indonesia (1969/1974), which included investigation of fisheries, this genus with tuna and oil-sardines had priority over other commercial species. During the late fifties an experimental canning project for this genus was unsuccessful due to miscalculation of the stock abundance and mistakes in estimating the economics of the project. Most investigations on Rastrelliger are confined to the neighbouring states of Indonesia. The most important contribution in the Indonesian waters was conducted by de Beaufort (1951) and only few observations have been recorded since. In contrast to the rather extensive fisheries investigations as described above, the identities of the species within the genus are still in doubt. There are many synonyms because local races or indivi• duals have been described under different names. The objectives of this thesis are: (1) to verify the species identities, (2) to study their morphometry, and (3) to estimate the population parameters to aid fisheries management. 2 II. MATERIALS AND METHODS During the 1972 fishing season (early West Monsoon) samples of Rastrelliger were collected from the two main fishing areas in the Java Sea, i.e., Tanjung Satai in the south west coast of Borneo and Jakarta in the north coast of Java (Figure 1). All the fish were collected from the same fishing gear, the shore seines having stretched mesh size of about 3.0 to 4.5 cm. The samples were temporarily preserved in formalin 10% (+ borax, to retard shrinkage) and transferred to 37% isopropyl alcohol.
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