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An Assessment of the Health Status and Edibility of Fish from Three Impoundments in the North West Province, South Africa

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An Assessment of the Health Status and Edibility of Fish from Three Impoundments in the North West Province, South Africa AN ASSESSMENT OF THE HEALTH STATUS AND EDIBILITY OF FISH FROM THREE IMPOUNDMENTS IN THE NORTH WEST PROVINCE, SOUTH AFRICA BY BYRON M. BESTER DISSERTATION SUBMITTED IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MAGISTER SCIENTIÆ IN AQUATIC HEALTH IN THE FACULTY OF SCIENCE AT THE UNIVERSITY OF JOHANNESBURG SUPERVISOR: PROF. G. M. WAGENAAR CO-SUPERVISOR: DR J. C. VAN DYK DECEMBER 2013 NOTE: The financial assistance of the National Research Foundation (NRF), University of Johannesburg (UJ) and Cancer Association of South Africa (CANSA) is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the author and are not necessarily attributed to the abovementioned institutions. M. Sc. – 2013 TABLE OF CONTENTS TABLE OF CONTENTS ...................................................................................................................... II ACKNOWLEDGEMENTS ................................................................................................................. VII LIST OF ABBREVIATIONS .............................................................................................................. VIII GLOSSARY OF TERMS .................................................................................................................... XI LIST OF TABLES .......................................................................................................................... XIII LIST OF FIGURES ........................................................................................................................ XVII ABSTRACT ................................................................................................................................. XIX 1. PROJECT OVERVIEW ....................................................................... 1 1.1. INTRODUCTION ............................................................................................................. 2 1.2. STUDY MOTIVATION ...................................................................................................... 2 1.3. STUDY DIRECTIVE .......................................................................................................... 5 1.3.1. Aims and Objectives ............................................................................................ 5 1.3.2. Hypothesis ........................................................................................................... 6 1.3.3. Study Approach ................................................................................................... 6 1.4. SELECTED SITES ............................................................................................................ 7 1.4.1. Roodekopjes Dam (RD) ....................................................................................... 7 1.4.2. Vaalkop Dam (VD) ................................................................................................ 7 1.4.3. Marico-Bosveld Dam (MBD) ............................................................................... 8 1.5. SELECTED SPECIES ......................................................................................................... 8 1.5.1. Clarias gariepinus .................................................................................................. 9 1.5.2. Cyprinus carpio ..................................................................................................... 9 1.6. SELECTED TARGET ORGANS ............................................................................................ 9 1.6.1. Gills ..................................................................................................................... 10 1.6.2. Liver .................................................................................................................... 10 1.6.3. Kidney ................................................................................................................. 10 1.6.4. Heart ................................................................................................................... 10 1.6.5. Gonads................................................................................................................. 11 1.6.6. Skin ...................................................................................................................... 11 2. BACKGROUND INFORMATION...................................................... 12 2.1. STATE OF AQUATIC ECOSYSTEMS ................................................................................... 13 2.1.1. Current Concerns ............................................................................................... 13 2.1.1.1. Eutrophication ................................................................................................ 13 2.1.1.2. Endocrine Disrupting Chemicals (EDCs) ......................................................... 14 2.1.1.3. Cancer ............................................................................................................ 14 2.2. STUDY AREA ............................................................................................................... 14 2.2.1. Location .............................................................................................................. 15 ii M. Sc. – 2013 2.2.2. Catchment-specific Impacts .............................................................................. 15 2.2.3. Socio-economic Climate .................................................................................... 16 2.3. SUBSTRATE ANALYSIS .................................................................................................. 16 2.3.1. Physico-chemical Parameters ........................................................................... 16 2.3.1.1. Temperature ................................................................................................... 17 2.3.1.2. pH .................................................................................................................... 17 2.3.1.3. Electrical Conductivity & Total Dissolved Solids (TDS) ................................... 17 2.3.1.4. Dissolved Oxygen ........................................................................................... 18 2.3.2. Chemical Analysis............................................................................................... 18 2.3.2.1. Organic ........................................................................................................... 18 2.3.2.1.a. Aldrin (HHDN) ..................................................................................................... 18 2.3.2.1.b. Chorpyriphos ...................................................................................................... 18 2.3.2.1.c. DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) ......................................... 19 2.3.2.1.d. Lindane (HCH) ..................................................................................................... 19 2.3.2.1.e. Nonylphenol (p-NP) ............................................................................................ 19 2.3.2.1.f. Terbuthylazine .................................................................................................... 19 2.3.2.2. Inorganic ........................................................................................................ 20 2.3.2.2.a. Arsenic (As) ......................................................................................................... 20 2.3.2.2.b. Beryllium (Be) ..................................................................................................... 20 2.4. SURVIVAL MECHANISMS OF FISH .................................................................................. 20 2.4.1. Fish as a Bioindicator Species ............................................................................ 21 2.4.2. Histopathology as a Biomarker ........................................................................ 22 2.5. NECROPSY-BASED HEALTH ASSESSMENT ....................................................................... 22 2.5.1. Haematological Assessment ............................................................................. 23 2.6. BIOMETRIC INDICES ..................................................................................................... 23 2.6.1. Condition Factor ................................................................................................ 23 2.6.2. Organo-somatic Indices..................................................................................... 23 2.6.2.1. Hepatosomatic Index (HSI) ............................................................................ 24 2.6.2.2. Splenosomatic Index (SSI) ............................................................................. 24 2.6.2.3. Gonadosomatic Index (GSI) ........................................................................... 24 2.7. HISTOLOGY-BASED FISH HEALTH ASSESSMENT (HBFHA) ............................................... 24 2.8. AGE ESTIMATION ........................................................................................................ 25 2.8.1. Otoliths ............................................................................................................... 25 2.8.2. Scales .................................................................................................................. 25 2.9. EDIBILITY ................................................................................................................... 25 2.9.1.
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