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BINDURA UNIVERSITY OF SCIENCE EDUCATION DEPARTMENT OF ENVIRONMENTAL SCIENCE AN ASSESSEMENT OF FISH CATCH RATES AND CATCH COMPOSITION OF THE SANYATI BASIN OF LAKE KARIBA STUDENT NAME: MAVURU ALLEN (REGISTRATION NUMBER): B1128943 A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS OF THE BACHELOR OF ENVIRONMENTAL SCIENCE HONOURS DEGREE IN WILDLUFE AND RANGELAND MANAGEMENT Date of submission - 30/04/2015 1 DEDICATION I dedicate this thesis to my mum . ii ACKNOWLEDGMENTS Special thanks to my academic supervisor Mr W Mhlanga who worked tirelessly during this research project. I would also like to acknowledge my field supervisor Mr Tendaupenyu I.T who is also the Officer in Charge at Lake Kariba Fisheries Research Institute (LKFRI) for his assistance and support during my study. Thanks to Mr Makumbe P and Mr Ngorima P who assisted in data analysis and all the advice. I also wish to thank the following people: Ranger Maziva, Ranger Machengo, Ranger Vhareta, Ranger Goza, Coxswain Chavuta, Senior Ranger Mr Chaita and the rest of the LKFRI staff for their assistance and support during my primary data collection. I would also like to acknowledge the support and cooperation by the Chairmen of Nyaodza fishing village (Mr Moforo S), the rest of the committee members and all fishermen at Nyaodza fishing camp, the Chairmen of Fothergill fishing village (Mr Anderson P), the rest of the committee members and all the fishermen during primary data collection. To friends and family thank you for your support. To my mum thank you for your love. The success of the thesis was made possible by the Zimbabwe Parks and Wildlife Management Authority and the LKFRI who provided all the necessary resources. iii ABSTRACT A study was conducted in the Sanyati basin to determine changes in catch, effort, catch per unit effort (CPUE) and the overall catch composition at Lakeside station from the year 2002 to 2012 and also to determine CPUE in the artisanal fishery. The study used both secondary and primary data. Secondary data was obtained from the Experimental fishing programme at Lakeside and primary data was collected from Nyaodza and Fothergill fishing villages. An Analysis of Variance was conducted on catch, effort and CPUE data. The results revealed that there was a significant difference in both catch and effort among the years (p<0.05). However, no significant difference was observed in CPUE among the years 2002 to 2012 (p>0.05). Synodontis zambezensis appeared as the most dominant species at Lake side station with an Index of Relative Importance (IRI) of just over 36% IRI followed by Hydrocynus vittatus having just over 29% IRI while the third dominant species was S agochromis codringtonii with an IRI of 24%. Catch, effort and catch composition for Nyaodza and Fothergill fishing villages were also determined and CPUE for the two fishing villages were compared to determine if there was a significant difference. A t test was conducted to determine if there was a significant difference between the two fishing villages among the sampled months and results revealed that there was no significant difference in mean CPUE between the two fishing villages in May and June ( p>0.05). However, a significant difference was noted between the two fishing villages for the month of July ( p<0.05). The exotic Oreochromis niloticus appeared as the most dominant species in the artisanal fishery contributing 50.03% of the catch at Nyaodza in terms of numbers and 57.51% at Fothergill fishing village.It was concluded that the experimental fishing at Lakeside station is not a true representative of the inshore fishery in Lake Kariba since the area is closed to commercial fishing. The dominance of S. zambezensis was attributed to the use of smaller mesh sizes in the experimental fishing. It was also concluded Oreochromis mortimeri is still one of the most important fish species in the artisanal fishery although its contribution has declined and has been replaced by the exotic Oreochromis niloticus . iv TABLE OF CONTENTS DEDICATION .................................................................................................................................... ii ACKNOWLEDGMENTS ................................................................................................................. iii ABSTRACT ....................................................................................................................................... iv TABLE OF CONTENTS .................................................................................................................... v LIST OF TABLES ............................................................................................................................ vii LIST OF FIGURES ......................................................................................................................... viii LIST OF ABBREVIATIONS ............................................................................................................ ix CHAPTER ONE ..................................................................................................................................... 1 1.0 BACKGROUND TO THE STUDY ............................................................................................. 1 1.2 PROBLEM STATEMENT ........................................................................................................... 3 1.3 AIM OF THE STUDY .................................................................................................................. 3 1.4 OBJECTIVES OF THE STUDY .................................................................................................. 3 1.5 RESEARCH QUESTIONS........................................................................................................... 3 1.6 JUSTIFICATION ......................................................................................................................... 4 CHAPTER TWO .................................................................................................................................... 5 2.0 LITERATURE REVIEW ............................................................................................................. 5 2.1 IMPORTANCE OF FISHERIES .............................................................................................. 5 2.2 HISTORY OF FISHERIES IN LAKE KARIBA ..................................................................... 5 2.3 EXPERIMENTAL FISHING ................................................................................................... 6 2.4 ARTISANAL FISHERY .......................................................................................................... 8 CHAPTER THREE .............................................................................................................................. 11 3.0 METHODOLOGY ..................................................................................................................... 11 3.1 STUDY AREA ....................................................................................................................... 11 3.2 DATA COLLECTION ........................................................................................................... 11 3.2 DATA ANALYSIS ................................................................................................................. 12 CHAPTER FOUR ................................................................................................................................. 14 RESULTS ......................................................................................................................................... 14 4.1 SPECIES RECORDED........................................................................................................... 14 4.2.1 CATCH IN EXPERIMENTAL FISHING ........................................................................... 15 4.2.3 EFFORT ............................................................................................................................... 15 4.2.4 CATCH PER UNIT EFFORT ............................................................................................. 16 4.2.5 SPECIES COMPOSITION .................................................................................................. 17 4.3 ARTISANAL FISHERY ............................................................................................................ 18 CHAPTER FIVE .................................................................................................................................. 20 v DISCUSSION ................................................................................................................................... 20 5.1 EXPERIMENTAL FISHING ..................................................................................................... 20 5.1.1 CATCH ................................................................................................................................ 20 5.1.2 EFFORT ............................................................................................................................... 20 5.2 CATCH PER UNIT EFFORT (CPUE) .................................................................................. 21 5.3 SPECIES ABUNDANCE ....................................................................................................... 22 5.2 ARTISANAL FISHERY 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