COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. How to cite this thesis Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujdigispace.uj.ac.za (Accessed: Date). DETERMINING THE BIOLOGICAL REQUIREMENTS OF SELECTED IMPORTANT MIGRATORY FISH SPECIES TO AID IN THE DESIGN OF FISHWAYS IN SOUTH AFRICA. By Mathew J Ross A Thesis submitted in fulfilment of the requirements for the Degree PHILOSOPHIAE DOCTOR In Aquatic Health In the Department of Zoology, Faculty of Science at the University of Johannesburg Supervisor: Professor Victor Wepener May 2015 TABLE OF CONTENTS LIST OF TABLES .................................................................................................................................. VII LIST OF FIGURES .................................................................................................................................. IX ACKNOWLEDGEMENTS ....................................................................................................................... XIV ACRONYMS AND ABBREVIATIONS ........................................................................................................ XVI SUMMARY ......................................................................................................................................... XVII CHAPTER 1: INTRODUCTION AND LITERATURE REVIEW ....................................................... 1 1.1. Background & Chapter Overview .................................................................................... 2 1.2. Fish Migrations ................................................................................................................ 3 1.2.1. Types of migrations ................................................................................................. 3 1.2.2. Reasons for migrations ........................................................................................... 5 1.2.2.1. Active migrations ................................................................................................ 5 1.2.2.2. Passive migrations ............................................................................................. 7 1.3. Barriers to Migration & Implications of River Fragmentation .......................................... 8 1.3.1. Types of migratory barriers ..................................................................................... 8 1.3.2. Implications of barriers on fish migration. ............................................................... 9 1.3.3. Fish migratory barriers and the South African perspective ................................... 12 1.4. What are Fishways? ...................................................................................................... 22 1.4.1. Historical overview of the development of the concept of fishways ...................... 22 1.4.2. Types of fishways .................................................................................................. 24 1.4.2.1. Pool-type fishways ........................................................................................... 26 1.4.2.2. Baffle fishways ................................................................................................. 33 1.4.2.3. Fish locks, lifts and elevators ........................................................................... 34 1.4.2.4. Natural and rock-ramp fishways ...................................................................... 36 1.4.2.5. Eel fishways (eelways) ..................................................................................... 39 1.4.2.6. Trap and transport fishways ............................................................................ 39 1.4.3. Fishways around the world ................................................................................... 40 1.4.3.1. North America, Canada & Alaska .................................................................... 40 1.4.3.2. South America ................................................................................................. 41 1.4.3.3. European Union ............................................................................................... 42 1.4.3.3.1. United Kingdom ..................................................................................... 42 ii | P a g e TABLE OF CONTENTS 1.4.3.3.2. Western Europe ..................................................................................... 43 1.4.3.3.3. Spain and Portugal ................................................................................ 44 1.4.3.4. Japan and China .............................................................................................. 45 1.4.3.5. India and Pakistan ........................................................................................... 46 1.4.3.6. Australia ........................................................................................................... 46 1.4.3.7. New Zealand .................................................................................................... 48 1.4.3.8. Africa ................................................................................................................ 48 1.4.3.8.1. North and Central Africa ........................................................................ 48 1.4.3.8.2. Southern Africa ...................................................................................... 48 1.4.3.8.2.1. Pool and weir-type fishways .......................................................... 51 1.4.3.8.2.2. Vertical slot fishways in South Africa ............................................. 55 1.4.3.8.2.3. Natural bypass channel ................................................................. 57 1.4.3.8.2.4. Combinations of fishway types ...................................................... 59 1.5. Freshwater Fish of Southern Africa............................................................................... 61 1.6. Hypothesis & Research Questions ............................................................................... 63 1.6.1. Research question ................................................................................................ 63 1.6.2. Hypotheses ........................................................................................................... 63 1.6.4. Specific research objectives .................................................................................. 64 1.6.5. Thesis outline ........................................................................................................ 65 1.7. References .................................................................................................................... 66 CHAPTER 2: LABORATORY TRIAL TESTING OF THE VERTICAL SLOT FISHWAY USING INDIGENOUS FISH SPECIES UNDER STEEPER GRADIENTS ............................................ 78 2.1. Introduction .................................................................................................................... 79 2.1.1. Choice of experimental fishway design ................................................................. 81 2.1.2. Hydraulic characteristics and concepts within a vertical slot fishway ................... 83 2.1.3. Biological aspects pertaining to the vertical slot fishway ...................................... 87 2.1.4. Aims and objectives .............................................................................................. 90 2.2. Materials & Methods ..................................................................................................... 92 2.2.1. Laboratory design.................................................................................................. 92 2.2.1.1. Environmentally controlled room ..................................................................... 92 2.2.1.2. Housing system ............................................................................................... 92 2.2.2. Experimental fishway channel specifications and variations ................................ 97 2.2.2.1. Standard vertical slot ....................................................................................... 97 2.2.2.1. Experimental fishway variations ...................................................................... 98 2.2.3. Fish species .......................................................................................................... 98 2.2.4. Acclimation of fish ................................................................................................. 99 2.2.5. Project plan and experimental design ................................................................. 100 2.2.5.1. Experimental protocol .................................................................................... 100 2.2.5.1.1. Stimulation phase ................................................................................ 100 2.2.5.1.2. Experimental phase ............................................................................