CIFA TECHNICAL PAPER   26

Status of fish stocks and fisheries of thirteen medium-sized African reservoirs CONTENTS

Martin van der Knaap

Internationaal Agrarisch Centrum
Wageningen, the Netherlands

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

M-40
ISBN 92-5-103581-4

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PREPARATION OF THIS DOCUMENT

Reservoir fisheries are important in Africa. This document is an effort to expand basic information on fisheries and related characteristics of African reservoirs in order to promote rational development and management. This document covers medium-sized reservoirs. Another document, now in preparation, entitled “Present Status of Fish Stocks and Fisheries of Kainji, Kariba, Nassar/Nubia and Volta Reservoirs”, will update information on some of the largest reservoirs. It builds on the reviews contained in Status of African Reservoir Fisheries (CIFA Technical Paper No. 10, 1984).

Comments on the publication and additional information on the reservoirs is welcome. Write to the Chief, FAO Inland Water Resources and Aquaculture Service, Viale delle Terme di Caracalla, 00100 Rome, Italy.

Distribution:

FAO Regional Offices
FAO Fisheries Department
CIFA Mailing List
Mailing List Aquaculture (Africa)
Author

Food and Agriculture Organization of the United Nations
Rome,
© FAO 1994

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.

This electronic document has been scanned using optical character recognition (OCR) software. FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

CONTENTS

1. INTRODUCTION

1.1 General

1.2 Fishery development projects

2. CAMEROON

2.1 Introduction

2.2 Lagdo Reservoir

2.2.1 Benue River

2.2.2 Pre-impoundment study

2.2.3 Limnology, hydrology and morphometry

2.2.4 Description of the fishery

2.2.5 Stock assessment

2.2.6 Management

2.3 Maga Reservoir

2.3.1 Logone River

2.3.2 Pre-impoundment study

2.3.3 Limnology, hydrology and morphometry

2.3.4 Description of the fishery

2.3.5 Stock assessment

2.3.6 Management

2.4 Mbakaou and Bamendjing Reservoirs

2.4.1 Sanaga River system

2.4.2 Pre-impoundment studies

2.4.3 Limnology, hydrology and morphometry

2.4.4 Description of the fishery

2.4.5 Stock assessment

2.4.6 Management

3. COTE D'IVOIRE

3.1 Introduction

3.2 Kossou Reservoir

3.2.1 Bandama River

3.2.2 Pre-impoundment study

3.2.3 Limnology, hydrology and morphometry

3.2.4 Description of the fishery

3.2.5 Stock assessment

3.2.6 Management

3.3 Buyo Reservoir

3.3.1 Sassandra and N'zo Rivers

3.3.2 Pre-impoundment study

3.3.3 Limnology, hydrology and morphometry

3.3.4 Description of the fishery

3.3.5 Stock assessment

3.3.6 Management

4. MALI

4.1 Introduction

4.2 Manantali Reservoir

4.2.1 Bafing River

4.2.2 Pre-impoundment study

4.2.3 Limnology, hydrology and morphometry

4.2.4 Description of the fishery

4.2.5 Stock assessment

4.2.6 Management

4.3 Sélingué Reservoir

4.3.1 Sankarani River

4.3.2 Pre-impoundment study

4.3.3 Limnology, hydrology and morphometry

4.3.4 Description of the fishery

4.3.5 Stock assessment

4.3.6 Management

5. SUDAN

5.1 Introduction

5.2 Jebel Aulia Reservoir

5.2.1 White Nile

5.2.2 Pre-impoundment study

5.2.3 Limnology, hydrology and morphometry

5.2.4 Description of the fishery

5.2.5 Stock assessment

5.2.6 Management

6. TANZANIA

6.1 Introduction

6.2 Mtera Reservoir

6.2.1 Great Ruaha and Kisigo Rivers

6.2.2 Pre-impoundment study

6.2.3 Limnology, hydrology and morphometry

6.2.4 Description of the fishery

6.2.5 Stock assessment

6.2.6 Management

7. ZAIRE

7.1 Introduction

7.2 Mwadingusha Reservoir

7.2.1 Lufira River

7.2.2 Pre-impoundment study

7.2.3 Limnology, hydrology and morphometry

7.2.4 Description of the fishery

7.2.5 Stock assessment

7.2.6 Management

8. ZAMBIA

8.1 Introduction

8.2 Kafue Flats/Gorge Reservoir Complex

8.2.1 Kafue River

8.2.2 Pre-impoundment study

8.2.3 Limnology, hydrology and morphometry

8.2.4 Description of the fishery

8.2.5 Stock assessment

8.2.6 Management

8.3 Itezhitezhi Reservoir

8.3.1 Kafue River

8.3.2 Pre-impoundment study

8.3.3 Limnology, hydrology and morphometry

8.3.4 Description of the fishery

8.3.5 Stock assessment

8.3.6 Management

9. SUMMARY

9.1 Comparison of subjects investigated

9.1.1 Species composition

9.1.2 Bush clearance

9.1.3 Introductions of fish species

9.1.4 Small clupeids

9.1.5 Fisheries management

9.2 Conclusion

10. RECOMMENDATIONS

BIBLIOGRAPHY

APPENDIX 1 Summary of geographical, meteorological, hydrological, chemical, physical and other data on Lake Kossou, Côte d'lvoire

LIST OF TABLES

1.1 List of reservoirs studied, including data on area and potential fish yields

2.1 Summary of limnological data for some Cameroonian rivers

2.2 Fishermen, boats and gear by ethnic group around Lake Lagdo, February 1990

2.3 Annual fish production by fishing enterprise at Lake Lagdo

2.4 Annual fish production by unit area at Lake Lagdo

2.5 Monthly average catch rates for gillnets of various mesh sizes

2.6 Species composition for three categories of gillnets, based on mesh size

2.7 Frame survey results of Maga Reservoir, Cameroon

2.8 Fish production from Maga Reservoir

2.9 Summary of figures on fishery potential of four reservoirs in Cameroon

2.10 List of fish species caught in the Maga Reservoir and Logone River

3.1 Summary of information on water level, surface and volume of Lake Kossou

3.2 Summary of physico-chemical data for Lake Kossou

3.3 Development of the fishery at Lake Kossou for the period 1972–1975

3.4 Number of fishing gear, boats, fishermen and fishing camps by administrative region

3.5 Annual fish yield estimates at Lake Kossou

4.1 Summary of baseline limnological data from Bafing River

5.1 Summary of physico-chemical data for Jebel Aulia Reservoir

5.2 List of commercial species in Jebel Aulia Reservoir, their contribution to the total production, and their local names

6.1 List of fish species caught in the Great Ruaha River and its tributaries

6.2 Summary of available data on number of fishermen, boats and gear as well as on fish production for the Mtera Reservoir

7.1 Summary of available physico-chemical data for the Mwadingusha Reservoir

7.2 Summary of existing annual catch figures for the Mwadingusha Reservoir

7.3 Species composition of Mutobi scoop nets by mesh size

7.4 Species composition data according to biotope, obtained through experimental fishing

7.5 Species composition data for two areas during various months of the year

7.6 Species composition data for all catches on the lake in the period 1957–1960

8.1 Summary of high-water and low-water estimates of ichthyomass for the Kafue Flats in 1970

8.2 Relative abundance by weight of 19 species of commercial fishes at high water and at low water on the Kafue Flats in 1970

8.3 List of commercial fish species with their vernacular names as used in the Kafue Plains

8.4 Summary of data on fish production on the Kafue Flats, 1957–1969

8.5 Summary of catch statistics, number of fishermen and boats on the Kafue Flats/Gorge Reservoir Complex

8.6 Periods of sexual activity of commercial fish species in the Kafue River

9.1 Summary of availability of data and information on subjects investigated

LIST OF FIGURES

1.1 Map of Africa indicating countries studied

2.1 Principal reservoirs in Cameroon

2.2 Shape of the Lagdo Reservoir

2.3 Annual variations in water level of Lake Lagdo, 1983–1987

2.4 Evolution of the number of masterfishermen around Lake Lagdo

2.5 Breakdown of masterfishermen by nationality

2.6 Quantities of fresh and processed fish marketed at Lagdo in 1989 and 1990

2.7 Monthly average catch rates for gillnets at Lake Lagdo in 1990

2.8 Monthly average catch rates for gillnets operated on motorized canoes around Lake Lagdo in 1990

2.9 Frequency of nets by mesh size as used in Lagdo in 1990

2.10 Length frequency of Sarotherodon galilaeus from gillnet catches of different mesh sizes

2.11 Shape of the Maga Reservoir

3.1 Map of Côte d'lvoire showing principal reservoirs

3.2 Shape of the Kossou Reservoir

3.3 Average catch rates for different mesh sizes in monofilament gillnets

3.4 Average catch rates for different mesh sizes in multifilament gillnets

3.5 Average catch rates for Pellonula afzeliusi in Lake Kossou

3.6 Species composition of gillnet catches in Lake Kossou

4.1 Principal reservoirs in Mali

4.2 Shape of the Manantali Reservoir

4.3 Sequential filling of Manantali Reservoir

4.4 Summary of frame survey results of Manantali Reservoir

4.5 Differences in species composition of catches from cleared and uncleared lake areas, Manatali Reservoir

4.6 Shape of the Sélingué Reservoir

5.1 Principal reservoirs in Sudan

6.1 Principal reservoirs in Tanzania

6.2 Shape of the Mtera Lake in the area of the dam

7.1 Principal reservoirs in Zaire

8.1 Principal reservoirs in Zambia