University of Ghana http://ugspace.ug.edu.gh UNIVERSITY OF GHANA, LEGON INVESTIGATIONS INTO HATCHERY AND NURSERY OPERATIONS FOR THE CULTURE OF THE FRESHWATER PRAWN (Macrobrachium vollenhovenii, Herklots 1857) IN GHANA DZIDZORNU KWAKU EDZORDZI ATSU SID: 10074463 THIS THESIS IS SUBMITTED TO UNIVERSITY OF GHANA IN PARTIAL FULFILMENT OF THE REQUIRMENT FOR THE AWARD OF THE DOCTOR OF PHILOSOPHY DEGREE IN FISHERIES SCIENCE JULY, 2018 University of Ghana http://ugspace.ug.edu.gh DECLARATION This thesis is the result of research work undertaken by Atsu, Dzidzornu Kwaku Edzordzi. in the Department of Marine and Fisheries Sciences, University of Ghana, under the supervision of Prof. P. K. Ofori-Danson, Prof. F. K. E. Nunoo and Dr. S. Addo. Atsu, Dzidzornu Kwaku Edzordzi. …………………………………………….… Date: ……………………… (Student) Prof. Patrick. K. Ofori-Danson ……………………………………………. Date: ……………………… (Principal Supervisor) Prof. Francis. K. E. Nunoo ……………………………….….………. Date: ………………………. Dr. Samuel Addo …………………………….…….………… Date: ………………………. University of Ghana http://ugspace.ug.edu.gh ABSTRACT The study was conducted to demonstrate hatching and larval development of the African River Prawn Macrobrachium. vollenhovenii Herklots, 1857) and to establish the spatial and temporal distribution of the prawns and related crustaceans in the Lower Volta River from Torgorme (Akuse) to Ada with focus on the Volta Estuary of Ghana. The ecological survey was undertaken from August 2013 to July 2014 followed with aspects of reproductive biology of the M. vollenhovenii from August 2014 to July 2015 and then the hatching and larval development of the from January to December 2016. Fisheries dependent data was collected together with experimental prawn fishing. The species encountered included Atya gabonensis (Giebel, 1875), Macrobrachium macrobrachion, (Herklots, 1851), Macrobrachium vollenhovenii and Penaeus spp. Comparatively more Penaeus spp. were sampled in the dry months (November to January) in more saline zones while Macrobrachium spp. were more in the rainy months (May to July) in the more freshwater zones. The dominant species in the estuary was the M. vollenhovenii (72.52%) with male to female ratio of 1:1.3 and non-berried to berried females ratio as 1:1.7. The berried females were obtained throughout the year with increased numbers and larger ones in the rainy season. The size and weight of gonad correlated positively with size of berried females and appeared to be a function of the number rather than the size of eggs. Out of four treatment media (Artificial Sea salt, Freshwater, Seawater and Rock salt) used for the larval development, the Freshwater medium could not support the life of the larvae after 48 hours. The 8th Larval stage (ZVIII) was observed from the 23rd day of culture in both Seawater and Artificial Sea Salt media. Survival rate correlated negatively with stocking densities of 50, 100, 150 and 200 larvae/liter, an indication that thinning is necessary as the larvae grow from one stage to another. Survival rates in the 50 larvae/liter were 36.8%, 30.8% and 25% in the Seawater, Artificial Sea salt and Rock salt ii University of Ghana http://ugspace.ug.edu.gh treatments respectively. From the results, M. Vollenhovenii larvae could be hatched and developed for culture in the grow-out process to boost prawn culture in Ghana. iii University of Ghana http://ugspace.ug.edu.gh DEDICATION I dedicate this work to my loving wife, Mrs. Edem Negble Atsu, my parents: Late Rev. E. M. Atsu and Madam Awo Fortune Gassor and to my idol friend and brother the Late Mr. Sievers Burghard of Germany. It was their love, dedication and support that saw me through my education up to this stage. iv University of Ghana http://ugspace.ug.edu.gh ACKNOWLEDGEMENT To God be the glory for great things He has done in my life and greater things He is yet to do. My sincere thanks go to my Supervisors: Prof. P. K. Ofori-Danson, Prof. F. K. E. Nunoo and Dr. Sam Addo all of Department of Marine and Fisheries Sciences, for their patience, encouragement and dedication to this work. My gratitude also goes to the former Head Prof. K. Appearning Addo and to Senior Members and Staff of Department of Marine and Fisheries Sciences, particularly Prof. G. Wiafe and Prof. Elvis Nyarko. To Mr. Emmanuel Aryee, Mr. Samuel Quaatey and Mr. Lionel Awity of Ministry of Fisheries and Aquaculture Development, I say may God richly bless and reward you for your encouragements and support. I am grateful to University of Ghana and the Fisheries Commission of Ghana for the financial support without which this work will not have been completed. v University of Ghana http://ugspace.ug.edu.gh TABLE OF CONTENTS DECLARATION ................................................................................................................................... i ABSTRACT ......................................................................................................................................... ii DEDICATION ..................................................................................................................................... iv ACKNOWLEDGEMENT .................................................................................................................... v TABLE OF CONTENTS..................................................................................................................... vi LIST OF FIGURES ............................................................................................................................. ix LIST OF PLATES ................................................................................................................................ x LIST OF TABLES ............................................................................................................................... xi CHAPTER ONE ................................................................................................................................... 1 GENERAL INTRODUCTION ..................................................................................................... 1 1.1 Background ............................................................................................................................. 1 1.2 Research Justification ............................................................................................................. 6 1.3: Research Design .................................................................................................................. 10 1.4 Objectives ............................................................................................................................. 10 CHAPTER TWO ................................................................................................................................ 12 GENERAL LITERATURE REVIEW ........................................................................................ 12 2. 1 Characteristics of Crustaceans for Culture .......................................................................... 12 2.2: The Most Commonly Farmed Taxonomic Groups of the freshwater Prawns ...................... 15 2.3: Distribution of the Freshwater Prawns ............................................................................... 16 2.4: Ecology and Life History ..................................................................................................... 18 2.5 Freshwater Prawn Fisheries .................................................................................................. 23 2.6 Global Prawn Culture Potential and Practices ...................................................................... 24 2.7 Prawn Species for Culture in the West Africa Sub-region ................................................... 25 2.8 Prawn Culture Systems ......................................................................................................... 26 CHAPTER THREE ............................................................................................................................ 32 SPATIAL AND TEMPORAL DISTRIBUTION OF FRESHWATER PRAWNS IN THE LOWER VOLTA RIVER IN GHANA ............................................................................... 32 3.1 Introduction ........................................................................................................................... 32 3.2: Materials and Method .......................................................................................................... 34 3.2.1 Study Area ......................................................................................................................... 34 Schematic Sketch of Freshwater Basket Prawn Traps ........................................................... 39 3.2.3. Identification and Morphometric Measurement ............................................................... 40 3.2.5 Summary and Analysis of Data: ........................................................................................ 41 3.3 Results ................................................................................................................................... 42 vi University of Ghana http://ugspace.ug.edu.gh 3.3.1 Occurrence and Distribution of Crustaceans Encountered in the Study Area ................... 42 3.3.2 Distribution of the Crustacean Species Encountered by Size and Body Weight. .............. 49 3.3.3 Water Quality Parameters and Distribution of the Crustaceans ....................................... 52 3.4 Discussion ............................................................................................................................