CHARACTERISATION OF THE HEALTH, HABITAT USE AND MOVEMENT OF ADULT LOWVELD LARGESCALE YELLOWFISH (LABEOBARBUS MAREQUENSIS SMITH, 1841) AND OTHER FISHES IN THE CROCODILE RIVER, KRUGER NATIONAL PARK. By MATTHEW JAMES BURNETT A Thesis submitted in fulfilment of the requirements for the Degree MASTERS OF SCIENCE In AQUATIC HEALTH IN THE DEPARTMENT OF ZOOLOGY, FACULTY OF SCIENCE AT THE UNIVERSITY OF JOHANNESBURG Supervisor: PROFESSOR VICTOR WEPENER (UNIVERSITY OF JOHANNESBURG) MAY 2013 i Thanks to God "But ask the animals, and they will teach you, or the birds of the air, and they will tell you; or speak to the earth, and it will teach you, or let the fish of the sea inform you. Which of all these does not know that the hand of the LORD has done this? In his hand is the life of every creature and the breath of all mankind.” Job 12:7-10 ii TABLE OF CONTENTS ACKNOWLEDGMENTS………………………………………………………………….....V SUMMARY…………………………………………………………………………………..VI LIST OF TABLE……………………………………………………………………………..IX LIST OF FIGURES………………………………………………………………………….IX LIST OF APPENDICES……………………………………………………………………XII 1 CHAPTER 1: INTRODUCTION AND PROBLEM FORMULATION. ................... 1 1.1 Study Area ................................................................................................. 6 2 CHAPTER 2: A COMPREHENSIVE LITERATURE REVIEW ON LOWVELD LARGESCALE YELLOWFISH, LABEOBARBUS MAREQUENSIS ........................... 8 2.1 Introduction ................................................................................................ 8 2.2 Labeobarbus marequensis past and present ............................................. 9 2.3 Labeobarbus marequensis biology and ecology ...................................... 11 2.4 Labeobarbus marequensis ecosystem service use .................................. 15 3 CHAPTER 3: BEHAVIOURAL STUDY OF AN ADULT POPULATION OF LOWVELD LARGESCALE YELLOWFISH (LABEOBARBUS MAREQUENSIS) IN THE CROCODILE RIVER, KRUGER NATIONAL PARK. ........................................ 17 3.1 Introduction .............................................................................................. 17 3.2 Material and Methods .............................................................................. 18 3.2.1 Biotelemetry systems ............................................................................... 18 3.2.2 Capture and tagging ................................................................................ 22 3.2.3 Monitoring techiniques ............................................................................. 27 3.2.4 Habitat preferences .................................................................................. 29 3.2.5 Behavioural variables ............................................................................... 30 3.2.6 Data analysis ........................................................................................... 31 3.3 Results ..................................................................................................... 31 3.3.1 Habitat Preference ................................................................................... 32 3.3.2 Behaviour variables ................................................................................. 42 3.4 Discussion ............................................................................................... 45 3.4.1 Habitat preferences .................................................................................. 45 3.4.2 Behaviour variables ................................................................................. 46 3.5 Conclusion ............................................................................................... 48 4 CHAPTER 4: METAL BIOACCUMULATION IN LOWVELD LARGESCALE YELLOWFISH (LABEOBARBUS MAREQUENSIS), TIGERFISH (HYDROCYNUS VITTATUS) AND SHARPTOOTH CATFISH (CLARIAS GARIEPINUS) FROM THE CROCODILE AND SABIE RIVERS, KRUGER NATIONAL PARK. .......................... 50 iii 4.1 Introduction .............................................................................................. 50 4.2 Materials and Methods ............................................................................. 52 4.3 Results ..................................................................................................... 53 4.4 Discussion ............................................................................................... 63 4.5 Conclusion ............................................................................................... 65 5 CHAPTER 5: GENERAL CONCLUSION AND MANAGEMENT RECOMMENDATIONS. .......................................................................................... 67 5.1 General conclusions ................................................................................ 67 5.2 Management recommendations ............................................................... 68 6 CHAPTER 6: REFERENCES .......................................................................... 70 7 CHAPTER 7: APPENDICES ............................................................................ 80 iv ACKNOWLEDGMENTS Special Thanks and appreciation to the following people and organisations My God and saviour Jesus Christ, who created all things and has given me the opportunity and ability to achieve all I have. Gordon O’Brien, for his support, expertise, assistance and his effort into helping me make this thesis a success. My Supervisor, Professor Victor Wepener for his professional assistance and expertise. My loving parents whom without their moral and continual support I would not have achieved what I have today Bruce Leslie, for his vision, fishing rod and rifle, without him none of this would have happened. The Head of Department in Zoology (University of Johannesburg) Professor J.H.J. van Vuren for the use of facilities. The South African National Parks (SANParks), Kruger National Park personal especially D. Pienaar and A. Deacon for there assistance and guidance throughout the study. The Water Research Commission (WRC) for funding the study. Mjejane Game Reserve, especially J. Bardenhorst who allowed us access and support during the study. Wireless Wildlife for their professional assistance in developing tags for the study. v SUMMARY Yellowfish and specifically Labeobarbus marequensis are a charismatic species targeted by anglers throughout South Africa. Their population are limited to the north- western parts of the country including the lower reaches of the Crocodile River that flows through the Kruger National Park (KNP). Despite conservation efforts the Crocodile River in the KNP is still highly impacted. The effect of these impacts on the ecosystem is largely unknown. The main aim of the study was to determine the influence of changing water quantity and quality in the Crocodile River on adult L. marequensis. This was achieved by evaluating altered flows (discharge) on the behaviour of adult L. marequensis in the Crocodile River using biotelemetry over a two year period. The influence of altered water quality was assessed using metal bioaccumulation as an indicator of metal exposure in L. marequensis, Clarias gariepinus and Hydrocynus vittatus in the Crocodile and Sabie Rivers during a high and low flow season. Biotelemetry was used on 16 L. marequensis and 12 H. vittatus to determine the habitat use and movement responses of the species. Fish were tagged with Advanced Telemetry Systems (ATS) and Wireless Wildlife (WW) tags and tracked remotely and manually. Home ranges were determined using Arc GIS ®, Habitat uses were analyzed using Windows Excel (© 2011, Microsoft inc.). Environment variables recorded were scored as primary and secondary and then combined with a weighting variable 2:1 ratio (primary variable: secondary variable). A mixed-model analysis of variance (ANOVA) approach with a random co-efficients model and Akaike’s information criteria (AIC) were used to test for significance. Analyses were conducted using SAS version 9 (SAS institute, Cary, NC). The habitat use of L. marequensis included cobble and boulder dominated flowing habitat biotopes. A strong affiliation for cover features including rocky outcrops, undercut banks and submerged woody and rock structures were also observed. Foraging behaviour took place predominantly within in these habitat types. A single spawning event was observed within a fast flowing, boulder dominated and 1-2m deep run. Seasonal habitat utilization differed significantly (p=0.04). Changes in discharge significantly (p=0.001) effected behaviour. During high flow periods the movement of fish decreased. Significant (p=0.05) changes in movement were observed during rapid moderate (increase of 11m3/s) and high (61 m3/s) changes in vi discharge. The study indicates that habitat available for L. marequensis is low within KNP and the focal area is important to the species. Reduction in habitat diversity could impact the behaviour of the species. The management of the timing, duration and frequency of flows are important for the biology and ecology of L. marequensis. For the metal bioaccumulations L. marequensis, C gariepinus and H. vittatus were caught in two rivers, the Sabie and Crocodile River during a high flow and low flow period. In total 19 L. marequensis, 23 C. gariepinus and 30 H. vittatus were used. The fishes spinal cords were severed and then dissected and muscle tissue removed and frozen for analysis. Tissue were then dried at 60°C for 48 hours, then after weighed and diluted in 1% HNO3 (AR) with Milli-Q water before digestion using HNO3/H2O2 and using