STUDIES ON THE CATCH AND SPECIES COMPOSITION OF SOME EDIBLE MARINE AND BRACKISH WATER CRABS IN THE GREAT KWA RIVER, CROSS RIVER STATE, CALABAR, NIGERIA

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ABSTRACT

This study on catch and species composition of some edible marine and brackish water crabs in the Great Kwa River, Nigeria was aimed at determining the species composition of sampled crabs per study site, to determine the species abundance of the sampled crabs per study site (the number of species found in the site), to determine the total species composition in all the sites throughout the study, to determine the percentage species composition in all the sites throughout the study. The following species;Callinectes amnicola, C. Pallidus and C. Marginatus belonging to the family (portunidae) were recorded between July and September, 2019 at Esuk Atu, Obufa Esuk and Esuk Anantigha beaches. A total of 55,915 crabs were recorded at the Esuk Atu Beach with 36,663 at Obufa Esuk Beach and 31,798 at Esuk Anantigha Beach. Callinectes amnicola was the most abundant crab species during the study period; with a total of 51, 292 individuals (40.27%). This was followed by C. Pallidus with 39,257 individuals (30.82%) and C. marginatus with 36,827 individuals (28.91%). In all the sampling sites, Esuk Atu, Obufa Esuk and Esuk Anantigha beaches a total number of 127,376 individuals crab was collected. No significant relations were found to exist between species abundance of the crab per sampling occasion and sampling sites during the survey (p<0.05) based on the results of Analysis of Variance (ANOVA).

TABLE OF CONTENTS

TITLE PAGE –           –           –           –           –           –           –           i          

DEDICATION           –           –           –           –           –           –           –           ii

CERTIFICATION                 –           –           –           –           –           –           iii       

ACKNOWLEDGMENTS                –           –           –           –           –           iv

ABSTRACT               –           –           –           –           –           –           –           vi

TABLE OF CONTENTS      –           –           –           –           –           –           vii

LIST OF TABLES                 –           –           –           –           –           –           11

LIST OF FIGURES  –           –           –           –           –           –           12

LIST OF PLATES                 –           –           –           –           –           –           13

CHAPTER ONE: INTRODUCTION

  1. Importance of the Study           –           –           –           –           –           1
    1. Justification                    –           –           –           –           –           –           9

1.3 Aims/Objectives of the Study  –           –           –           –           –           10

CHAPTER TWO: LITERATURE REVIEW                –           –           11

CHAPTER THREE: MATERIALS AND METHODS           

3.1 Description of the Study Area             –           –           –           –           20

3.1.1 Climate             –           –           –           –           –           –           –           24

3.1.2 Vegetation       –           –           –           –           –           –           –           24       

3.1.3 Human Activities       –           –           –           –           –           –           24

3.1.4 Sampling Site              –           –           –           –           –           –           25

3.2 Field of Study     –           –           –           –           –           –           –           25

3.2.1 Reconnaissance Survey        –           –           –           –           –           25

3.2.2 Sampling Regime (Work Plan)         –           –           –           –           26

  • Collection of Samples         –           –           –           –           –           26

3.2.4 Preservation and Transportation of Samples         –           –           26

3.3 Laboratory Analysis     –           –           –           –           –           –           26

3.3.1 Sorting and Identification of Samples         –           –           –           26

3.3.2 Counting of Samples              –           –           –           –           –           27

3.3.3 Photographs of Samples        –           –           –           –           –           27

3.3.4 Determination of Species Composition per Site of Collection              29

3.3.5 Determination of Species Composition per Sampling Occasion           29

3.3.6 Determination of Species Abundance per Sampling       

           Site (Relative Catch)                        –           –           –           –           –           29

3.3.7   Determination of Species Abundance per Sampling

                        Occasion (Relative Catch)              –           –           –           –           29

3.3.8 Determination of the Total Species Abundance in all the Sites                        30

3.3.9 Determination of the Percentage Species Composition in

                 all the Site Combined     –           –           –           –           –           30

3.4 Statistical Analysis        –           –           –           –           –           –           30

CHAPTER FOUR: RESULTS

  • 4.1  Species Composition     –           –           –           –           –           –           31

4.1.1 Check List of Species Sample          –           –           –           –           31

4.1.2 Species Composition per Sampling Occasion       –           –           33

4.1.3 Species Composition per Sampling Station           –           –           37

4.2 Species Abundance (Catch)                 –           –           –           –           37

4.2.1 Species Catch per Sampling Occasion        –           –           –           37

4.2.2 Species Abundance per Sampling Station  –           –           –           39

4.2.3 Total abundance (Catch) of all the species at the

         different sampling sites during the study (pooled data)   –           44

4.2.4 Total Abundance (Catch) of all Species per Sampling                

       Occasion (Pooled Data            –           –           –           –           –           46

4.2.5 Percentage Abundance (Catch) of Different Species in

all the Stations throughout the study        –           –           –           48

CHAPTER FIVE: DISCUSSION

5.1 Species Composition                –           –           –           –           –           51

5.2 Species Abundance       –           –           –           –           –           –           52

5.3 Percentage Abundance             –           –           –           –           –           54

CHAPTER SIX: SUMMARY AND CONCLUSION    –           58

REFERENCES          –           –           –           –           –           –           –           59

APPENDIX                –           –           –           –           –           –           –           67