STUDIES ON THE BIOLOGY AND FISHERY OF THE FISHES OF THE FAMILY PRIACANTHIDAE (PISCES : PERCIFORMES) OF INDIAN WATERS THESIS Submitted to THE COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY By K. P. PHILIP, M. Sc. DEPARTMENT or INDUSTRIAL FISHERIES COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY COCHIN - 682 016 1994 DECLARATION I, K.P. Philip, do hereby declare that the thesis entitled "STUDIES ON THE BIOLOGY AND FISHERY OF THE FISHFS OF THE FAMILY PRIACANTHIDAE (PISCI-'S=PERCIFORMFS) OF INDIAN WATERS" is a genuine record of research work done by me under the supervision and guidance of Dr. Kuruvila Mathew, Reader, Department of Industrial Fisheries, Cochin University of Science and Technology and has not been previously formed the basis for the award of any degree, diploma, associateship, fellowship or other similar title of any University or Institution. September,Kochi -1994 682 K.P. 016PHILIP CERTIFICATE This is to certify that this thesis is an authentic record of research work carried out by Sri. K.P. Philip, M.Sc. under my supervision and guidance in the Department of Industrial Fisheries, Cochin University of Science and Technology in partial fulfilment of the requirements for the degree of Doctor of Philosophy and that no part thereof has been submitted for anyother degree. 9% (KURUVILA MATHEW) Supervising Teacher Dr Kuruvila Mathew Reader Department of Industrial Fisheries 9--9-1994Cochin Cochin University Cochin of Science - and682 Technology 016 ACKNOWLEDGEMENT I wish to express my sincere gratitude to Dr. Kuruvila Mathew, Reader, Department of Industrial Fisheries, Cochin University of Science and Techno­ logy for suggesting this problem and guiding me with encouragement and constant support throughout the course of this work. I acknowledge my sincere thanks to Dr. M. Shahul Hameed, Professor and Head of the Department of Industrial Fisheries and to Dr. C.T. Samuel, former Head of the Department, Cochin University of Science and Technology for their valuable suggestions and constant support and also for providing necessary facilities to carry out this work. I am greatly indebted to Dr. D. Sudarsan, Director General, Fishery Survey of India, for permitting me to undertake this study and for extending all sorts of support, guidance and encouragement throughout the course of this study. I am very much thankful to the Ministry of Agriculture and the Ministry of Food Processing Industries, Government of India for allowing me to carry out this work on part—time basis and for allowing me to make use of the data collected by the survey vessels of the Fishery Survey of India. I am also thankful to the Cochin University of Science and Technology for granting me registration for Ph.D. programme. My sincere thanks and gratitude are due to Shri. K. Vijayakumar, Scientist, Central Marine Fisheries Research Institute, Visakhapatnam for the assistance he has rendered for statistically analysing and computing the data and also for all the help rendered during this study. I am indebted to Dr. M. Madhusoodhana Kurup, Reader, Department of Industrial Fisheries and Dr. C.J. Cherian, Associate Professor, Kerala Agricultural University for critically going through the manuscript and giving valuable suggestions. The valuable assistance rendered by S/Shri. Paul Pandian, Junior Fishing Gear Technologist, N. Jagannath, Sr. Scientific Assistant and S.M. Reddy, Scientific Assistant and all my colleagues in the Fisheries Section of the Zonal Base of Fishery Survey of India, Visakhapatnam and Shri. P.J. Joseph, Junior Fisheries Scientist of Cochin Base is acknowledged with great apprecia­ tion. I express my sincere thanks to Shri. Antony Joseph, Statistician, Fishery Survey of India, Bombay for the assistance rendered for the compilation of distribution data on priacanthids. I thank Dr. K. Sujatha, Reader, Andhra University and Dr. V.V. Rao, Retd. Senior Fisheries Scientist, Fishery Survey of India, for the assistance given to me in the taxonomic studies. My thanks are also due to S/Shri. I(.P. Reghunath, Junior Stenographer and C.S.N. Murty, Accountant, Fishery Survey of India for the secretarial assistance. CONTENTS Page No. GENERAL INTRODUCTION 1.1 Review of previous work 1.2 Review on priacanthid fishery along the Indian waters 10 1.3 Research approach 12 SYSTEMATICS 14 2.1 Introduction 14 2.2 Material and methods 16 2.3 Distinguishing characters of family Priacanthidae 2.4 Key to the genera of family Priacanthidae of Indian waters 18 2.5 Key to the species of Priacanthus 25 Plates 1-3 Tables 1-2 FOOD AND FEEDING 31 3.1 Introduction 31 3.2 Material and methods 33 3.3 Results 36 3.3.1 Composition of food 36 3.3.2 Seasonal variations in the food composition 37 Page No. 3.3.3 Spatial difference in food composition 40 3.3.4 Variations of food in relation to depth 41 3.3.5 Variations of food in relation to size groups 42 3.3.6 Feeding intensity 42 3.3.7 Gastro—somatic index 43 3.3.8 Comparative study of food of E. hamrur with that of E. japonicus 43 3.4 Discussion 44 Figures 2-4 Tables 3-8 MATURATION AND SPAWNING 49 4.1 Introduction 49 4.2 Material and methods 50 Results 53 4.3. 4.3.1 Macroscopic study of gonads 53 4.3.2 Maturity stages 54 4.3.3 Development of ova to maturity E 58 4.3.4 Spawning season 58 4.3.5 Depth-wise distribution of maturity stages 60 4.3.6 Size at first maturity 61 4.3.7 Gonado-somatic index 61 4.3.8 Fecundity 62 Page No. 4.3.9 Sex ratio 63 4.4 Discussion 64 Figures 5-8 Tables 9-23 5. LENGTH—WEIGHT RELATIONSHIP AND RELATIVE CONDITION FACTOR 72 5.1 Introduction 72 5.2 Material and methods 74 5.3 Results 76 5.4 Discussion 77 Figures 9-11 Table 24 AGE AND GROWTH 81 6.1 Introduction 81 6.2 Material and methods 83 6.2.1 Modal progression analysis 84 6.2.2 Fitting of von Berta1anffy's growth’equation 87 6.3 Results 89 6.4 Discussion 91 Table 25 Figures 12-18 Page No. MORTALITY AND EX PLOITATION 95 7.1 Introduction 95 7.2 Material and methods 95 7.3 Results 100 7.4 Discussion 102 Figure 19 DISTRIBUTION OF THE STOCK AND FISHERY 106 8.1 Spatial and temporal distribution of the stock 106 8.1.1 Introduction 106 8.1.2 Material and methods 107 8.1.3 Results 111 8.1.3.1 Area-wise distribution 111 8.1.3.2 Depth-wise distribution 112 8.1.3.3 Seasonal abundance 114 8.1.3.4 Contribution of priacanthids to the total catch 116 8.1.3.5 Variation in annual abundance 118 8.1.3.6 Biomass 119 8.2 Fishery and utilization 119 8.2.1 Fishery 119 8.2.2 Utilization 122 8.3 Discussion 123 Figures 20 Tables 26-38 SUMMARY 129 10. REFERENCES 139 GENERAL INTRODUCTION 1. GENERAL INTRODUCTION Fisheries form. an important sector in the Indian economy. With an annual production of 4.04 million tonnes in 1991 (Anon, 1994), India occupies seventh position among the fish producing nations and second among the shrimp producers of the world. Apart from providing employment for nearly 7 million fisherfolks, this sector contributes to 2.4% of the GDP from primary industries. The 7,500 km coastline has over 2500 fishermen villages and as many traditional fish landing centres. There are about 34,000 mechanised boats, 170 of them having OAL above 23 m, (Joseph and Deviah, 1993) and 1.8 lakhs traditional crafts in this country. The export of fish products from India during 1992 was 1,91, 314 tonnes valued at Rs.1581.44 crores, forming 3.5% of the total export earnings (Anon, 1993a). The country's marine fish landings rose from an average of 0.8 million tonnes in 60's through 1.2 million tonnes in 70's and 1.6 million tonnes during 80's to the current production of 2.29 million tonnes. Of the 2.29 million tonnes of marine production in 1992,pelagic resources like sardines, mackerel, Bombay duck, ribbon fish, carangids etc. contributed to 1.19 million tonnes (52%) while the demersal resources such as elasmobranchs, lizard fish, croak­ ers, threadfin bream, goat fish, prawns, cephalopods etc. accounted for 1.1 million tonnes (48%). The south west region with 36.1%, topped in production followed by north west (34.1%), while south east and north east accounted for 23.4 and 5.5% respectively (Anon, 1993b). With the declaration of 200 nautical miles Exclusive Economic Zone (EEZ) in 1976, India acquired full rights to explore, exploit, manage and conserve the living and non-living resources of nearly two million sq.km. of seas around it. Attempts were made by various workers to estimate the resources potential of the EEZ by resorting to organic production and exploratory survey data (Jones and Banerji, 1973; Silas, 1977; Geoge e_t a_l. 1977; Joseph, 1980, 1985, 1987; Nair and Gopinathan, 1981; Alagaraja, 1989; Desai fl a_l. 1989; Mathew e_t a_l. 1990 and Sudarsan fl a_l. 1990). These estimates showed that the potential marine resources of India ranged between 2.3 to 5.5 million tonnes. As more accurate figures are needed for develop­ mental planning, recently Government of India appointed a working committee for revalidating the fishery potential of the EEZ (Anon, 1991) and the comm­ ittee estimated the resources of the EEZ as 3.92 million tonnes. Of this the demersal stocks form about 1.93 million tonnes, the coastal pelagic stocks share 1.74 million tonnes and the oceanic stocks contributed to the remaining 0.25 million tonnes (Sudarsan, 1993).