As a follow-up to the Study on International Fisheries Research (SIFR, 1989-91), FAO, in collaboration with the Economic Commission for Africa and the European Union, launched in 1992 a regional study on aquaculture development and research in sub-Saharan Africa. The resulting synthesis of the information presented in 12 national reviews on development and research needs, provided the basis for proposing an indicative Action Plan for Aquaculture Research in sub-Saharan Africa in 1994. Eight priority research programmes were identified among which "Aquaculture in irrigation schemes" and "Small water body fisheries enhancement" were included. These programmes would operate as networks and would be supported by an Aquatic Systems Information Network already proposed in 1997.

Since 1995, the FAO Special Programme for Food Security (SPFS) is gradually being implemented in several African countries. It includes an irrigation component which should develop and demonstrate appropriate irrigation technologies which can be effectively sustained by small-scale farmers. The SPFS also includes a diversification component including rural aquaculture. Small-scale aquaculture could be successfully integrated with irrigation whenever local conditions permit, resulting in a number of varied benefits from practical, social, economical and agricultural points of views.

In the context of sub-Saharan Africa, small-water bodies (SWB) are generally defined as small man-made impoundments of water built primarily for domestic use, livestock watering, and/or irrigation, where fish production is usually a secondary use. SWB fisheries differ significantly from natural lake fisheries and are susceptible to enhancement. Seasonally variable water levels and the resulting magnification of environmental variation, artificial assemblages of mainly riverine fish species in a lacustrine environment, and relatively small surface areas are all characteristics which may be exploited through improved management and aquaculture techniques to increase fish production.

Aware of such potential developments, the Inland Water Resources and Aquaculture Service of the FAO Fisheries Department organized in October 1997 an identification mission in sub-Saharan Africa with the following objectives:

• to visit some of the existing research institutions previously identified as potential contributors to a research network for the integration of aquaculture and irrigation, including fisheries enhancement in small irrigation reservoirs;
• to evaluate the resources available in each of these institutions to contribute to such a network;
• to ascertain existing interest and willingness to do so;
• to briefly review the status of aquaculture and irrigation development in each country visited;
• to identify possible ways for integration and related constraints;
• to identify potential founder-members of this new research network;
• to identify a possible way for the initial establishment of such a network.

From 22 October to 21 November 1997, the mission visited various institutions concerned with fisheries and irrigation research and/or development in Ghana, Burkina Faso, Mali, Zambia and Zimbabwe. In each of them, it evaluated the potential participation of the visited country into a research network for the integration of aquaculture and irrigation on the basis of existing infrastructure and resources available to support research and development in the fields of aquaculture, small water bodies fishery enhancement and irrigation. Past experience in the integration of aquaculture into irrigation schemes was also reviewed.

Except in Ghana and in Zambia where aquaculture research infrastructure is being completed with external assistance, it is still rather rudimentary in the other three countries visited. Staff and financial resources are very limited in most countries, although in Zambia this situation could improve in the near future as a result of the training component of a new UNDP aquaculture project. In Ghana, aquaculture research will most probably receive increased attention following its integration within the Water Research Institute and the recent change in Government policy.

In general, government resources (infrastructure, staff, finances) are rather limited, particularly in Burkina Faso, Mali and Zimbabwe. Although some private initiatives exist in Mali (stocking of small reservoirs) and in Ghana, they are particularly developed in Zambia (fish farms and small reservoirs). Extension services have been reorganized in most countries where the "training and visit" system is applied by polyvalent extensionists (unified system).

In all countries, juvenile fish production cannot cope with the demand. Wild juveniles of tilapias and African catfish are captured from reservoirs, floodplains and rivers by local fishermen mostly to stock small reservoirs. Annual aquaculture productions are relatively low (80-150 t), except in Ghana and in Zambia.

Fisheries enhancement in small water bodies (SWB) through stocking has been and/or is still being carried out in all the visited countries. In this last instance, private initiatives are mostly responsible, either at village level (Mali and Ghana) or at farm level (Zambia and Zimbabwe). The current situation in the countries visited is as follows:

During the past five years in Zambia and Zimbabwe, the FAO Aquaculture for Local Community Development Programme (ALCOM) has tested and developed, methodologies for the rapid evaluation of SWB fishery potential and for community-based enhancement/management of SWB fish resources. Guidelines are now being prepared which should prove useful for other countries.

Surface irrigation with full or partial water control which offers the best possibilities for integrating aquaculture, in particular in large-scale irrigation schemes, is mostly developed in Mali. Zambia and Zimbabwe have each more than 20000ha available, much more than Burkina Faso and Ghana. In this last country, the actually irrigated area is only 61percent of the equipped area, although great efforts are now made to rehabilitate old schemes.

Overhead irrigation by sprinklers is particularly well developed in Zimbabwe and even in Zambia. Actual tendency is to prefer this irrigation system which uses available water resources much more efficiently. For the same reason, micro-irrigation (drip) is being increasingly used in southern Africa.

Wetlands and/or inland bottom valleys are particularly extended in Zambia where these dambos are traditionally irrigated by hand and where the SPFS is actually concentrating its efforts. It has been shown that several possibilities exist to integrate small-scale fish farming in such areas. Burkina Faso and Zimbabwe (as well as Ghana probably) have also relatively extended wetlands used by smallholders. In Mali, such areas are limited to the south western part of the country.

Flood-dependent irrigation is practiced in Mali in the Niger River valley over a large area. Results have been disappointing in recent years following the reduced river peak flood level. Little potential for integrating aquaculture exists in such type of irrigation schemes.

Irrigation potential is huge in Ghana and nearly four times greater than the potential in Mali and Zambia, the next countries with good potential. Smallest potential is found in Burkina Faso.

All kinds of integration of aquaculture in large irrigation schemes have been tried in Mali a few years ago and further trials have been proposed more recently. Good experience is also present in Ghana where an integration policy exists for a long time. Even if several proposals have been made in Burkina Faso at the Sourou irrigation scheme in the past, none have been implemented, although the enhancement of SWB fisheries has been practiced throughout the country for several years.

As far as informal irrigation in wetlands is concerned, the Zambia SPFS is actively carrying out the most recent trials on small-scale fish farming integration into small-holder irrigation.

Integration of aquaculture into the SPFS irrigation component is well ahead in Zambia where it is has been supported by a full time aquaculturist, with technical assistance from a consultant and ALCOM. In the other countries, aquaculture is under consideration, but the SPFS has still to get fully underway.

National institutions apt to become initially members of the new research network have been identified in each of the countries visited, except in Zimbabwe where a regional development project has been proposed.

The recommended institutions are as follows:

The new research network for aquaculture integration into irrigation schemes should become closely associated with other networks active in Africa and specialized in irrigation, regional development or fisheries.

Future collaboration with these networks will be particularly useful for the organization of seminars/workshops, for group training and for dissemination of information through existing channels such as newsletters and publications.

It is proposed that the following steps be successively taken to initially establish the new network:

(i) An official invitation should be addressed by FAO to the Director of the selected institutions to participate in the Seminar proposed below.

(ii) Author’s contracts should be issued for the preparation of national reviews/syntheses according to a standard framework by each of the institutions having expressed an interest to participate in the Seminar, with or without support from other institutions according to needs.

(iii) A Seminar to be organized with the objectives of:

• reviewing the development and research constraints existing in the participating countries, in particular following the outline agreed for the national reviews;
• discussing the future organization responsibilities and functioning of the new network, in particular from the point of view of using two languages, English and French;

• agreeing on applied research priorities and a research programme for the new network to support the development of the integration of aquaculture and irrigation;
• recommending how such research could be carried out in the field in each of the involved countries, with particular attention to the human and financial resources to be mobilized to this effect; and
• recommending how best close links could be established with other existing African networks of interest.

Participants in such seminar should include representatives from the selected countries, directly involved in research and/or development of irrigation, aquaculture and SWB fisheries. Representatives of other existing networks should also be invited to share their past experiences with networking and to stimulate future collaborative activities.

A series of research topics are suggested, addressing both general and particular aspects of aquaculture integrated into irrigation schemes. Specialized research should be considered for:

• undrainable fish farming structures;
• ponds with an unusually high water exchange rate;
• ponds built in waterlogged areas, in terrain depressions or in borrowing pits;
• fish farming in paddy fields;
• fish production in irrigation canals, either in pens or in floating cages;
• culture-based fisheries either in irrigation canals or in small irrigation reservoirs.