LIST OF ACRONYMS

8.1 Aquaculture Research and Development

8.1.1 Aquaculture research

8.1.2 Aquaculture development

8.1.3 Small water bodies and their fishery enhancement

8.1.4 Integration of aquaculture and irrigation

8.2 Irrigation Potential and Development

8.3 Status of the FAO Special Programme for Food Security

8.4 Review of Possible Integrated Systems

8.4.1 Fish farming in irrigated rice schemes

8.4.2 Fish farming in large-scale irrigation networks

8.4.3 Fish farming in smallholder schemes

LIST OF ACRONYMS

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. Staff and financial resources are also very limited in most countries, although in Zambia this situation could improve in the near future as a result of the training component of the UNDP aquaculture project. Even in Ghana, aquaculture research will most probably receive increased attention following its integration within the Water Research Institute and the change in Government policy.

Responsible institution(s) and research stations in each of the visited countries are as follows:

a/ See List of Acronyms at beginning of this Chapter

b/ In parentheses: station non or partly functional

A summary of the status and constraints of aquaculture development in the countries visited is given in the table below.

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, this last country being one of the largest cultured-fish producers in sub-Saharan Africa.

a/ In parentheses, non or partly functional stations

b/ Mostly from culture-based fisheries in small reservoirs

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 in Mali and Ghana or at farm level in Zambia and Zimbabwe.

The fisheries of small storage reservoirs located upstream from irrigation schemes may be enhanced by the following:

• improved fishing techniques (gears, boats, methods);
• improved management (access control, closed season, fishing pressure, zoning, etc.);
• introduction of new fish species to improve the use of natural productivity (available ecological niche);
• regular and periodic stocking of juvenile fish to replenish existing stocks (culture-based fishery);
• use of artificial aggregation structures such as brushparks.

During the past five years, the ALCOM Programme has tested and developed, in Zambia and Zimbabwe, methodologies for the rapid evaluation of SWB fishery potential and for community-based enhancement/management of SWB fish resources. Guidelines are now being prepared.

The current situation in the countries visited is as follows:

Existing past and present experience in integrating aquaculture and irrigation in the visited countries is summarized in the table below.

All types 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 (Coche and M�ller-Fall, 1993). 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 (Sourou irrigation scheme) in the past, none has been implemented, except for the enhancement of SWB fisheries (EDF Project 1986-91).

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 (van der Mheen, 1997).

Existing experience and proposals in integrating aquaculture and irrigation^b/

For further details on types of integration of aquaculture and irrigation see Section 8.4.

As shown in the table below, 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 especially Ghana with only about 6000ha. In this last country, the actually irrigated area is only 61 percent 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 practised in Mali in the Niger River valley over a large area. Results have been disappointing in recent years following the reduced peak flood level. Little potential for integrating aquaculture exists in such 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.

Irrigation in the visited countries (FAO/AGLW, 1995)

As of November 1997, the implementation of the pilot phase of the FAO Special Programme for Food Security had reached the following stage:

Integration of aquaculture into the SPFS irrigation component is well ahead in Zambia where it has been strongly supported by a full time FAO/APO aquaculturist, with technical assistance from a SAFR consultant and ALCOM.

In the other countries, aquaculture is under consideration, but the SPFS has still to get fully underway.

The integration of aquaculture and irrigation may be implemented in various ways, according to the farming system locally used and the type of irrigation scheme present. In addition, such integration, although much less direct, can also take place in small irrigation storage reservoirs (SWB) through the enhancement of its fishery.

Integrated systems which have been tried in the past in Africa, generally on a limited scale, are briefly mentioned in the next sections for information.

In large-scale schemes, water is usually available during the rice production cycle only, and then sometimes not even on a continuous basis. When crop diversification is promoted, as for example in Mali (Office du Niger and S�lingue rice schemes) certain areas are specifically designed for horticultural production. Irrigation water is then available throughout the year which allows the integration of aquaculture easily.

The following integrated systems have been tried:

• ponds are built upstream of the irrigated plots;
• irrigated plots are used as fish ponds on a rotational basis, either between two successive crop cycles or in alternance at longer intervals to improve soil fertility;
• a few irrigated plots are transformed into permanent ponds;
• rice and fish are farmed together after adapting the paddy field to accommodate fish.

Water originates from a stream diversion, a large reservoir or a pumping station. It is fed to the irrigated plots through a network of canals (primary, secondary, tertiary...). In such cases, integration of aquaculture can be realized either as described above for the particular case of irrigated paddy fields or as follows:

• in ponds used as intermediate water storage structures located between the main water intake and the irrigated plots;
• in ponds located in the irrigated plots, preferably upstream from the plots used for crop production, generally vegetables;
• in ponds located next to a surelevated irrigation canal permanently underwater (generally primary or secondary canals), usually outside the crop production areas;
• in fenced areas (pens) built in an irrigation canal;
• in cages floating in an irrigation canal;
• in ponds created by enlarging/deepening natural draining channels, streambeds or terrain depressions;
• in ponds created from clay-borrowing pits (bricks/banco) next to villages;
• in earth borrowing pits (road/dykes) preferably designed at the initial construction stage;
• in irrigation canals as a culture-based fishery;
• in the reservoir, either as culture-based fisheries or in cages.

Several possibilities for small-scale fish farming integration exist which have been well described by H. van der Mheen (1996, 1997) based on his recent surveys in Zambia, Tanzania and Zimbabwe. The following possibilities have been identified:

• improved use of high water discharge from a reservoir (gate valve or siphon), a spring or a diversion canal through intermediate storage ponds built along the main irrigation canal;
• improved use of irregular water supply shared by several farmers on a rotational basis: intermediate storage ponds for individuals or small groups of farmers;
• improved use of a constant water flow from a spring not continuously used for irrigation (for example, at night): intermediate night storage reservoirs along the irrigation canals;
• ponds built in waterlogged areas, such as in the lower areas of inland valley bottoms (wetlands/dambos) where a high water table is present throughout the year:
  • in flat areas, surelevated wide banks may be used for crop farming;
  • in sloped areas, cut-and-fill ponds can be designed to be drained by gravity.
• ponds as enlarged irrigation shallow wells with sloping sides;
• ponds not directly integrated into the irrigation water system, water-fed directly and independently from an irrigation canal.