Review of tropical reservoirs and their fisheries

FAO Fisheries and Aquaculture Technical Paper No. 557


Review of tropical reservoirs and their fisheries

The cases of Lake Nasser, Lake Volta and Indo Gangetic Basin reservoir


Edited by

P.A.M. van Zwieten
Aquaculture and Fisheries Group
Wageningen University
The Netherlands

C. Béné
Policy, Economics and Social Science
The WorldFish Center
Penang, Malaysia

J. Kolding
Department of Biology
University of Bergen
High Technology Centre
Bergen, Norway

R. Brummett
Agriculture and Rural Development
World Bank
Washington, DC, United States of America

and

J. Valbo-Jørgensen
Fisheries and Aquaculture Resources Use and Conservation Division
Food and Agriculture Organization of the United Nations
Rome, Italy


 

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Food and Agriculture Organization of the United Nations
Rome 2011


ABSTRACT

van Zwieten, P.A.M.; Béné, C.; Kolding, J.; Brummett, R.; Valbo-Jørgensen, J., eds. Review of tropical reservoirs and their fisheries – The cases of Lake Nasser, Lake Volta and Indo-Gangetic Basin reservoirs. FAO Fisheries and Aquaculture Technical Paper. No. 557. Rome, FAO. 2011. 148 pp.

Freshwaters contribute 15 percent of the world’s reported fish catch, or about 10.1 million tonnes in 2006, most of which comes from tropical systems. The true contribution of tropical inland fisheries is likely to be higher, as less than half of the inland capture production is actually reported. While reservoir fisheries are already an essential component of this production, the potential of most of them may even exceed their current catch levels. Opportunities exist to increase productivity, provided that environmentally and socially sustainable management systems can be adopted. To realize this untapped potential, it is necessary to improve understanding of the processes influencing reservoir productivity in such a way as to involve both biological principles and stakeholder participation, as each reservoir has different properties and different research and management institutions.
Seen in isolation, catch and productivity data of individual reservoirs may be difficult to interpret. The present technical paper attempts to address this issue by reviewing the knowledge accumulated in reservoirs in some very different tropical river basins: the Indus and Ganges/Brahmaputra Basin in India, the Nile River Basin in Eastern Africa and the Volta River Basin in West Africa. In particular, it focuses on many of the reservoirs of northern India and Pakistan in the Indus and Ganges systems, Lake Nasser in the Nile River and Lake Volta in the Volta River.
Information collated from grey and published literature on the three basins is synthesized and standardized with reference to wider knowledge and up-to-date information on tropical reservoir fisheries. A considerable quantity of data and information were collected on many aspects of the systems of the three reservoirs, including hydrological, biophysical and limnological features, primary production, and fish and fisheries data. This information was condensed and synthesized with the aim of providing a baseline against which the ecological changes that have taken place since impoundment can be described and analysed. Efforts are made to explain changes in fish catch in relation to climatic variations, ecological succession and fishing effort. The review shows that biological data and information are generally available.
However, as is also common elsewhere, all three cases suffer from the general tendency to isolate and compartmentalize research into separate disciplines. Usually, there is very limited cross-disciplinary flow of information or recognition of how results of various disciplines can contribute to a more comprehensive understanding of the behaviour of fish populations, human communities and ecosystems and the productive activities that depend on them. This uniform tendency severely hampered the identification of relevant management actions.
A more pragmatic and holistic understanding of reservoir ecosystems is needed in order to guide the choice of indicators and the development of monitoring systems that can inform management of changes in reservoir productivity and, hence, the potential catch. The next step would be to devise a hierarchy of indicators describing the different ecological and economic processes influencing fisheries catches and to organize monitoring systems around those indicators. Only by combining information across sectoral disciplines will it be possible to reach a better understanding of the processes that drive fish stocks, fisheries and reservoir productivity.



Table of Contents

Preparation of this document
Abstract
Acknowledgements
Abbreviations and acronyms

  pdf file [290Kb]
   

PART I

  pdf file [1.8Mb]

1. General Introduction

  

2. Reservoirs in the Indo-Gangetic Basin of India

 

3. Lake Nasser , Egypt

  
   

PART II

  pdf file [1.2Mb]

4. Lake Volta, Ghana

  

5. General Discussion

  

Appendix 1. Lake Nasser: additional tables
Appendix 2. Lake Volta: additional tables and information

  


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