BIONOMICS, RESOURCE CHARACTERISTICS AND DISTRIBUTION OF THE THREATENED FRESHWATER FISHES OF KER A THESIS SUBMITTED TO THE COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY EUPHRASIA C. ]. SCHOOL OF INDUSTRIAL FISHERIES COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY KOCHI — 682016 2004 DECLARATION I, Euphrasia C.J., do hereby declare that the thesis entitled “BlONOMICS, RESOURCE CHARACTERISTICS AND DISTRIBUTION OF THE THREATENED FRESHWATER FISHES OF KERALA” is a genuine record of research work carried out by me under the guidance of Dr. B. Madhusoodana Kurup, Professor, School of Industrial Fisheries, Cochin University of Science and Technology, Kochi-16 and no part of the work has previously formed the basis for the award of any Degree, Associateship and Fellowship or any other similar title or recognition of any University or institution. Kochi — 682018 'aw. (2/7n_aL 30"‘ July 2004 EUPHRASIA c. J. CERTIFICATE This is to certify that the thesis entitled “BIONOMICS, RESOURCE CHARACTERISTICS AND DISTRIBUTION OF THE THREATENED FRESHWATER FISHES OF KERALA” is an authentic record of research work carried out by Mrs. Euphrasia C. J. under my guidance and supervision in the School of Industrial Fisheries, Cochin University of Science and Technology in partial fulfilment of the requirements for the degree of Doctor of Philosophy and no part thereof has been submitted for any other degree. Kochi — 682016 Dr. B. Madhusoodana Kurup 30”‘ July, 2004 (Supervising Guide) Professor School of Industrial Fisheries Cochin University of Science and Technology, Kochi — 16 I wish to express my profound sense of gratitude and indebtedness to my Supervising Guide Dr. B. Madhusoodana Kurup, Professor, School of Industrial Fisheries, Cochin University of Science and Technology for his unfailing guidance, invaluable advices, intellectual inputs, critical assessment and constant encouragement throughout the tenure of my research work. His patience and friendly support, especially during the preparation of the manuscript are highly commendable. I am thankful to Prof. (Dr.) Ramakrishnan Korakandy, Director, School of Industrial Fisheries, Prof. (Dr.) M. Shahul Hameed and Prof. (Dr.) C. Hridayanathan, former Directors of the School of Industrial Fisheries for providing me the necessary facilities to carry out the work successfully. I also record my deep sense of gratitude to the CCPI of NAT-ICAFI project on ‘Germplasm Inventory, Evaluation and Gene Banking of Freshwater Fishes’, School of Industrial Fisheries, Cochin University of Science and Technology for giving me a chance to associate with the project and accomplish the investigation on the threatened fishes of Kerala. A work of this magnitude would not have been possible without the whole-hearted co­ operation and constant assistance from Mr. K.V. Radhakrishnan and Mr. Manojkumar T.G., Senior Research Fellows, NAT-ICAFI project, School of Industrial Fisheries and Field Assistant, Mr. M.D. Mahasn. I am very much indebted to them and extend my wholehearted and sincere gratitude to them. My sincere thanks are also due to Ms. Neethu K.G., Data Entry Operator of the NAT-ICAFI Project. I am sincerely thankful to Dr. C.K. Radhakrishnan, Head of the Department of Marine Biology, Microbiology and Biochemistry and Dr. A. V. Saramma for kindly permitting to avail the facility for taking photographs. The co-operation extended by Mr. Pius, Lecturer, Christ College, lringalakuda and Ms. Nikita Divakaran, Research Scholar, School of Marine Sciences is also gratefully acknowledged. I sincerely thank Dr. M. Harikrishnan, Lecturer, St. Albert's college, Ernakulam for his valuable help in the analysis of data. The invaluable help rendered to me by Dr. Benno Pereira, Lecturer, St. A|bert’s college, Ernakulam during the preparation of the thesis is gratefully acknowledged. I am happy to record my sincere gratitude to the members of the teaching, administrative and supporting staff, School of Industrial Fisheries, for their help and co-operation throughout the course of my research work. I acknowledge with thanks the financial assistance received from University Grants Commission. I also express my deep sense of gratitude to the Principal and Management of St. Xavier’s College, Aluva, for permitting me to undertake the Ph.D. Programme under the Faculty Improvement Programme of U.G.C. I wish to place on record my heartfelt thanks to Rev. Sr. Speciosa, Former Principal, St. Xavier's College and my colleagues, especially Mrs. Vimala Cross and Mrs. Merita Paul, who were an unfailing source of inspiration to me. The acknowledgement will not be complete without expressing my thanks to all my fellow research scholars of Aquaculture and Capture Fisheries for the constant encouragement and lively discussions. The assistance extended to me by Mr. K.|. Poulose and Mr. Allen Lopez of Computer Park, Ernakulam North, Cochin -18 for the computerized preparation of the thesis is acknowledged with immense gratitude. My heartfelt gratitude to my loving husband, our affectionate daughter and other family members for their continuous motivation and encouragement as well as for their kind understanding, patience and sacrifices. ABOVE ALL, I thank God Almighty for His abundant blessings showered upon me during the entire period of my Ph.D. Programme. Euphrasia C. J. THE EARTH IS FULL OF GOODNESS OF GOD, OUR LORD “In the beginning the Lord did his work of creation, and gave everything a place of its own. He arranged everything in an eternal order And decreed that it should be that way for ever”. Sirach 16 :26-27. THE EARTH IS IN OUR HANDS, CONSERVE IT. CONTENTS Page Chapter 1 General Introduction 1.1. Introduction 1.2. Review of Literature 1.3. Objectives of the study 10 1.4. General organization of the thesis 12 SECTION I The Threatened Freshwater Fishes of Kerala Chapter 2 The Threatened freshwater fishes of Kerala 2.1. Introduction 15 2.2. Materials and methods 19 2.2.1. IUCN Red List Categories 24 2.3. Results 25 2.3.1. Threatened fishes of Kerala 27 2.3.1.1. Critically endangered fishes 27 2.3.1.2. Endangered fishes 51 2.3.1.3. Vulnerable fishes 89 2.4. Discussion 124 SECTION II Bionomics and Resource Characteristics of Osteobrama bakeri (Day) Chapter 3 Systematics of Osteobrama bakeri (Day) 3.1. Introduction 133 3.2. Description of the species 134 3.3. Earlier reports 136 Chapter 4 Biochemical composition 4.1. Introduction 140 4.2. Materials and methods 143 4.3. Results 144 4.4. Discussion 146 Chapter 5 Food and Feeding 5.1. introduction 154 5.2. Materials and methods 157 5.3. Results 159 5.3.1. General diet composition 162 5.3.2. Variation in diet composition of 164 males, females and indeterminates 5.3.3. Seasonal variations in the 165 diet of males and females 5.3.4. Feeding intensity 167 5.4. Discussion 171 Chapter 6 Reproduction 6.1. Introduction 183 6.2. Materials and methods 185 6.3. Results 189 6.3.1. Gametogenesis 189 6.3.2. Stages of maturation 193 6.3.3. Monthly % of occurrence of gonads 195 indifferent stages of maturity 6.3.4. Pattern of progression of ova 197 during different months 6.3.5. Gonadosomatic index 198 6.3.6. Length at first maturity 199 6.3.7. Sex ratio 199 6.3.8. Fecundity 201 6.4. Discussion 203 Chapter 7 Length — Weight relationship and Condition factor 7.1. Introduction 227 7.2. Materials and methods 228 7.3. Results 230 7.4. Discussion 235 Chapter 8 Age and Growth 8.1. Introduction 245 8.2. Materials and methods 248 8.3. Results 250 8.3.1. Distribution of length 250 8.3.2. Estimation of growth parameters 250 8.4. Discussion 253 Chapter 9 Population Dynamics 9.1. Introduction 258 9.2. Materials and methods 260 9.2.1. Total mortality coefficient 260 9.2.2. Natural mortality coefficient 263 9.2.3. Fishing mortality coefficient 264 9.2.4. Length based cohort analysis 264 9.2.5. Exploitation rate 265 9.2.6. Exploitation ratio 265 9.2.7. Relative yield per recruit and 265 relative biomass per recruit 9.3. Results 266 9.4. Discussion 268 Chapter 10 Summary and Recommendations 10.1. Summary 271 10.2. Recommendations 281 References Publications CHAPTER I GENERAL INTRODUCTION 1.1. Introduction The basic characteristic of life is its unlimited diversity. Biodiversity is the outcome of natural evolution which had been going on for the last 3.5 billion years. It refers to the abundance and the variety within and among fauna and flora, as well as the ecosystems and ecological processes to which they belong to and is thus usually considered at ecosystem, species and genetic levels. Ecosystem diversity refers to the variety of habitats and species communities as well as the ecological processes within ecosystems whereas species diversity refers to the variety of living organisms and genetic diversity to the total genetic information contained in the genes of an individual species (Kottelat and Whitten, 1996). ‘Freshwater biodiversity’ refers to the species and habitats within inland waters. Inland fisheries have the potential to provide good quality protein and their products can benefit the people without the need for complex and expensive harvesting, processing, marketing and transportation infrastructures. Potential fish yields vary from system to system and are a function of interacting abiotic and biotic factors. These fishery resources, upon which people depend on, are renewable when managed scientifically, on the other hand, when abused, they can become extinct. Unfortunately, the fishing sector seems to follow the latter path. Due to the increasing pressure from growing population and rapid modernization, ichthyobiodiversity is now getting depleted at an unprecedented rate. Fish habitats are destroyed as a consequence of many factors. Headwater regions of streams are altered by deforestation which, in turn, results in soil erosion, landslides and siltation, thereby destroying the breeding habitats of many species.