Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1979 Life history of Chrysichthys catfish in Volta Lake, Ghana Chief John Vanderpuye Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agriculture Commons, and the Animal Sciences Commons Recommended Citation Vanderpuye, Chief John, "Life history of Chrysichthys catfish in Volta Lake, Ghana " (1979). Retrospective Theses and Dissertations. 7313. https://lib.dr.iastate.edu/rtd/7313 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 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ZEEB ROAD, ANN ARBOR, Ml 48106 18 BEDFORD ROW, LONDON WCIR 4EJ, ENGLAND 8010264 VANDERPUYE, CHIEF JOHN LIFE HISTORY OF CHRYSICHTHYS CATFISH IN VOLTA LAKE, GHANA Iowa State University PH.D. 1979 University Microfilms I n t© r n 3t i O n 3.1 300 N. Zeeb Road, Ann Arbor, MI 48106 18 Bedford Row, London WCIR 4EJ, England Life history of Chrysichthys catfish in Volta Lake, Ghana by Chief John Vanderpuye A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Animal Ecology Major; Fishery Biology Approved; Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. For the Major Department Signature was redacted for privacy. For the Graduate College Iowa State University Ames, Iowa 1979 ii TABLE OF CONTENTS Page INTRODUCTION 1 The Volta Lake 7 Main Study Area 13 The Fishery 22 Prior Studies on the Fish Species in Volta Lake 24 MATERIALS AND METHODS 26 IDENTIFICATION OF CHRYSICHTHYS SPECIES IN VOLTA LAKE 37 ABUNDANCE AND DISTRIBUTION 48 Temporal and Areal Changes 52 Depth Distribution 56 Length-Frequency Distributions 60 REPRODUCTIVE BIOLOGY 7Ob Maturity Stages 7Ob Sex Ratios 84 Size of Ovaries and Eggs 86 Fecundity 89 Preferred Spawning Site 99 Spawning Behavior and Spawning 101 Habitat Preference of the Juveniles 102 WEIGHT-LENGTH RELATIONSHIP 103 Condition Factor 105 RECOMMENDATIONS FOR FUTURE RESEARCH 112 SUMMARY 116 LITERATURE CITED 121 iii TABLE OF CONTENTS (Continued) Page ACKNOWLEDGEMENTS 126 APPENDIX 129 iv LIST OF TABLES Page Table 1. List of sampling stations: all except 1, 5 and 6 were sampling stations in the stock sampling program 29 Table 2. Morphological comparisons between the four Chrysichthys species in Volta Lake 38 Table 3. Comparison of number of gill-rakers of Chrysichthys spp in Volta Lake 39 Table 4, Large specimens of Chrysichthys captured in other bodies of water in Africa 45 Table 5. Numbers of Chrysichthys and other species taken at Ampem in survey samples (except for 13 mm mesh nets), June 1975 to May 1976, and percentages of Chrysichthys in the ichthyofauna 49 Table 6, Distribution of Chrysichthys in Volta Lake during the period January to May 1970 50 Table 7. Numbers of bagrids and of other fish in catches in Areas 3, 7 and 8 during August 1974 to May 1975 taken by gill nets (excluding 13 mm mesh), traps and rotenone 51 Table 8. Temporal abundance of Chrysichthys in Volta Lake by seasons as monitored by standardized gang of experi­ mental gill nets by the Stock Assessment Section of the VLRP during the period, December 1969 to February 1972 53 Table 9, Distribution of Chrysichthys in gill nets in inshore and surface of offshore waters during the period December 1969 to February 1972, as monitored by a standardized gang of experimental gill nets by the Stock Assessment Section of the VLRP during the period December 1969 to February 1972 57 Table 10. Area and depth distribution of Chrysichthys in Volta Lake as monitored by a standardized gang of experi­ mental gill nets by the Stock Assessment Section of the VLRP during the period, December 1969 to February 1972 60 V LIST OF TABLES (Continued) Page Table 11. Length frequency distributions of £. velifer captured with different types of gear and rotenone in varying depths during the period, October 1974 to November 1975 62 Table 12. Length frequency distribution of C. auratus captured with different types of gear and rotenone in varying depths during the period October 1974 to November 1975 63 Table 13. Length frequency distribution of C, walkeri captured with different types of gear and rotenone in varying depths during the period October 1974 to November 1975 64 Table 14. Length distribution of C. furcatus captured with different types of gear and rotenone in varying depths during the period October 1974 to November 1975 65 Table 15. Length frequency distribution of C. velifer (by months) during the period April -""December 1975 66 Table 16. Length frequency distribution of C, auratus (by months) during the period April - December 1975 66 Table 17. Length frequency distribution of C. walkeri (by months) during the period April - December 1975 67 Table 18. Length frequency distribution of C. velifer (by months) during the period April to December 1975 67 Table 19. Length frequency distribution of C. auratus (by months) during the period April to December 1975 68 Table 20. Length frequency distribution of C. walkeri (by months) during the period April to December 1975 69 Table 21. Deviation of abundant size groups of C. velifer from calculated average ratio for the period June to December 1975 70a Table 22. Maturity of female C. auratus by size groups showing the number of fish at various stages of maturity in each 1 cm length group for all females sexed during the period December 1974 to November 1976 71 vi LIST OF TABLES (Continued) Page Maturity of female C. velifer by size groups showing the number of fish at various stages of maturity in each 2 cm length group for all females sexed during the period December 1974 to November 1976 72 Maturity of female C. walkeri by size groups showing the number of fish at various stages of maturity in each 1 cm length group for all females sexed during the period December 1974 to November 1976 73 Length distribution of spawning Chrysichthys captured on breeding grounds 74 Changes in the maturity of male G, auratus with size, showing the number of fish at various stages of maturity in each 1 cm length group for all males sexed during the period September 1975 to August 1976 82 Changes in the maturity of male C. walkeri with size showing the number of fish at various stages of maturity in each 1 cm length group for all males sexed during the period September 1975 to August 1976 82 Changes in maturity of male C, velifer with size showing the number of fish at various stages of maturity in each 2 cm length group for all males sexed during the period September 1975 to August 1976 83 Sex-ratios at various lengths of Chrysichthys cap­ tured at Ampem during the period September to November 1975 85 Sex-ratios at various lengths of Chrysichthys cap­ tured at Ampem during the period December 1975 - February 1976 86 Comparison of size of left and right ovaries in C. walkeri and £. auratus 87 Fecundity of Chrysichthys spp in Volta Lake during the period 1974 to 1977 90 Log weight-log length regression equations by species and sex for Chrysichthys spp in Volta Lake during the period 1974 - 1977 106 vii LIST OF TABLES (Continued) Page Table 34. Log weight-log length regression equations by species and quarter of the year for Chrysichthys captured in Volta Lake, during the period 1974 to 1977 107 Table 35, Regressions of log K on log SL based upon geometric mean, log W-log SL regressions 109 Table A-1.