i DECLARATION Declaration by the candidate This thesis is my original work and has not been submitted for any academic award in any institution; and shall not be reproduced in part or full, or in any format without prior written permission from the author and/ or University of Eldoret. Matolla Geraldine K. Signature …………..… Date…………….. (SC/DPhil/033/07) . Declaration by the Supervisors This thesis has been submitted with our approval as University supervisors. Prof. Dr. Phillip O. Raburu Signature……………… Date……..……… University of Eldoret Dr. Moses Ngeiywa Signature…..…….…… Date……………… University of Eldoret ii DEDICATION I dedicate this work to you my dear children Cynthia Wanza and Dion Mwema. You are my inspiration. God bless you. iii ABSTRACT Sustainability of culture-based fisheries (CBF) development in small water bodies (SWBs) largely depends on their ecological conditions and productivity. Studies were conducted from November 2010 to July 2012 in Kesses and Kerita dams in Uasin Gishu and Mauna and Yenga dams in Siaya. Sampling for water quality, phytoplankton, macroinvertebrates and fish parasites was conducted once a month. Phytoplankton and macroinvertebrates were collected using plankton and scoop nets respectively. Water quality parameters were measured in-situ using electronic meters. Parasitological examination was done according to standard procedures. Significant differences in temperature (F=17.38; p=0.000), DO (F=8.76; p= 0.000) and TN (F= 6.34; p=0.01) were found between Uasin Gishu and Siaya dams. Water pH in Kesses was higher during the wet season (F=14.44; p= 0.000) while TN and TP were higher during the dry season (F=9.38; p=0.02) and F=5.02; p=0.023 respectively). Similarly in Kerita, pH was higher during the wet season (F=15.98; p=0.01) while TN and TP were high during the dry season (F=43.21; p=0.00 and F=20.03; p=0.003 respectively). In Siaya, DO was higher during the rainy season (F=6.60; p= 0.01). During the wet season, Bacillariophyceae was more abundant in Kerita dam (H=5.45; p=0.02) and Desmidiaceae (H=4.07; p=0.044) in Kesses dam. The relative abundance of Ephemeroptera (H=16.07; p=0.003) and Plecoptera (H= 16.07; p=0.000) was higher during the wet season in Kesses while Hemiptera (H= 16.07; p=0.000) and Pulmonata (H= 9.04; p=0.002) was high during the dry season. Diplostomum parasites were associated with high TP levels in Kesses (rs= 0.621; p=0.0001) and with temperature (rs= 0.63; p= 0.002) in Mauna. Parasites affected the condition factor depending on seasonality and sex of fish. In Kesses, the condition factor of fish infected with Tylodelphys during the dry season was found to be significantly higher than un-infected ones (F= 18.86; p=0.000). While it is evident that seasonality and geographical location based on altitude have an effect on some aspects of water quality, phytoplankton, macroinvertebrates and parasites of fish in these SWBs, they are considered suitable for fish production as they are rich in phytoplankton and macroinvertebrate communities which serve as food. Development of mitigation measures against habitat degradation and water quality deterioration combined with strong community support for sustainable culture-based fisheries in these SWBs are recommended. iv TABLE OF CONTENTS PAGE DECLARATION ........................................................................................................ i DEDICATION ........................................................................................................... ii ABSTRACT.............................................................................................................. iii LIST OF TABLES .................................................................................................. viii LIST OF FIGURES ................................................................................................... xi LIST OF PLATES....................................................................................................xiv LIST OF ABBREVIATIONS, ACRONYMS AND SYMBOLS................................ xv ACKNOWLEDGEMENT ........................................................................................xvi CHAPTER ONE........................................................................................................1 INTRODUCTION .....................................................................................................1 1.1 Background......................................................................................................1 1.2 Problem Statement ..........................................................................................8 1.3 Justification .....................................................................................................9 1.4 Objectives of the study .................................................................................. 11 1.4.1 Overall Objective ..................................................................................... 11 1.4.2 Specific Objectives ................................................................................... 11 1.5 Hypotheses ..................................................................................................... 12 CHAPTER TWO .................................................................................................... 13 LITERATURE REVIEW ....................................................................................... 13 2.1 Overview ........................................................................................................ 13 2.2 Water quality ................................................................................................. 14 2.2.1 Physico-chemical Parameters ................................................................... 14 2.2.2 Nutrients .................................................................................................. 19 2.3 Phytoplankton Composition, Abundance and Primary Productivity ........ 25 2.3.1 Composition .................................................................................................. 25 2.3.2 Abundance ..................................................................................................... 27 2.3.3 Primary Productivity ...................................................................................... 28 2.4 Macroinvertebrates Composition, Abundance and Biomass ....................... 29 2.4.1 Composition ............................................................................................. 29 2.4.2 Abundance ............................................................................................... 32 2.4.3 Biomass.................................................................................................... 34 v 2.5 Abundance, Prevalence and Mean Intensity of Fish Parasites .................... 36 2.5. 1. Abundance of fish parasites ...................................................................... 36 2.5.2. Fish Parasite Prevalence ................................................................................ 39 2.5.3 Fish Parasite Mean Intensity .......................................................................... 41 2.6 Effect of Water Quality and Seasonality on Biota ........................................ 42 2.6.1 Effect Water Quality and Seasonality on Phytoplankton ........................... 43 2.6.2 Effect Water Quality and Seasonality on Macroinvertebrates .................... 44 2.6.3 Effect Water Quality and Seasonality on Parasites .................................... 47 2.8 Information Gaps .......................................................................................... 49 CHAPTER THREE ................................................................................................ 51 MATERIALS AND METHODS ............................................................................ 51 3.1 Study Area ..................................................................................................... 51 3.1.1 Preliminary Survey for Selection of Small Water Bodies .......................... 54 3.1.2. Small Water Bodies Selected in Uasin Gishu ............................................ 56 3.1.3. Small Water Bodies Selected in Siaya ...................................................... 57 3.2 Study Design .................................................................................................. 59 3.3 Sampling Design ............................................................................................ 59 3.4 Determination of Water Quality ................................................................... 65 3.4.1 Physico-chemical Water Quality Parameters............................................. 65 3.4.2 Nutrients .................................................................................................. 66 3.5 Phytoplankton Community Structure and Primary Productivity ............... 68 3.5.1 Community Structure of Phytoplankton .................................................... 68 3.5.2 Primary Productivity of Phytoplankton ..................................................... 68 3.6 Macroinvertebrates Community Structure and Biomass ............................ 70 3.6.1 Macroinvertebrate Community Structure .................................................. 70 3.6.2 Biomass of Macroinvertebrates................................................................. 72 3.7 Fish Parasites Prevalence and Mean Intensity ............................................. 73 3.7.1 Isolation of Fish Parasites