Fish has been an important source of food for centuries and contributes around 50 percent of total animal protein in the diets of many Africans (FAO, 2003b). However, as the industrialized worlds fish stocks depleted, the fish trade increasingly turned to developing countries for fish (Wilson, 1997). Although marine and inland capture fisheries play a significant role in African economies, the situation appears unsustainable as resources are already fully exploited and so increasing fishing effort will not increase catches (Cushing, 1988; FAO, 1991; NEPAD, 2003). People are threatened with food insecurity when overall supplies dwindle and prices increase. During the last decade, African fish production stagnated, the import surplus did not keep pace with population growth and the per caput availability of fish in Africa fell from about 9 kg/caput/year to 7 kg/caput/year (NEPAD, 2003). At the global level, aquaculture helps to fill the gap between the rising demands for fishery products and the current capture fisheries production and it could therefore make a significant contribution to food security in sub-Saharan Africa.
Although the practice of aquaculture in sub-Saharan Africa is relatively recent, it is not new to the majority of countries (Vincke, 1995; see Box 1). The development and wide adoption of the technology can therefore be seen as an important step towards improving household food security. Aquaculture is one of the fastest growing food-producing sub-sectors (Subasinghe, 2003; see Figure 1) but, although nearly 85 percent of world aquaculture production comes from developing countries (Ahmed and Lorica, 2002), sub-Saharan Africa currently contributes less than one percent of total aquaculture production by weight (FAO, 2003b). African aquaculture is still essentially a rural, secondary and part-time activity, taking place in small farms with small freshwater ponds (Coche, Haight and Vincke, 1994; Aguilar-Manjarrez and Nath, 1998). However the sector is expected to continue to expand into the next century (Li, 1999) with the industry responding to the growing demand for fish by improving production efficiency and product quality, domesticating additional species and using biotechnology to improve stock performance (Sverdrup-Jensen, 1999). Estimates suggest that 31 percent of sub-Saharan Africa is suitable for smallholder fish farming (Kapetsky, 1994) and so clearly the availability of land is not a constraint for aquaculture development in this region (Aguilar-Manjarrez and Nath, 1998). Nevertheless, although rapid commercialization may produce more fish in less time, there are inevitably a number of constraints limiting the expansion of aquaculture and questioning its sustainability in the long run. Current factors impeding aquaculture development in sub-Saharan Africa include: limited direct investment, which will only occur if potential profits exceed an acceptable risk level (Ridler and Hishamunda, 2001); undefined or poorly defined land and water rights (Hishamunda and Manning, 2002); and a limited availability of feed, the provision of which can have substantial negative environmental impacts (Naylor et al., 2000; Bruinsma, 2003). Fortunately as awareness of these limitations increases, many of the constraints that were previously inextricably linked to aquaculture are surmountable and therefore no longer common (FAO, 2003a).
The lack of tradition of fish and water husbandry in sub-Saharan Africa and the past socio-economic, environmental and political constraints have limited investment and slowed the expansion of African aquaculture leaving sub-Saharan countries in an extremely difficult food situation (Pinstrup-Anderson, Pandya-Lorch and Rosegrant, 1999); Brummett and Williams, 2000). Future aquaculture is working towards a product that is not only acceptable to consumers in terms of price, quality and safety, but also in terms of environmental cost (Jia et al., 2001). Predictions also suggest an improvement in the future economic state of sub-Saharan Africa (Bruinsma, 2003), which may therefore reduce the prevalence of food insecurity and widespread poverty. The extent of the contribution of fish and fisheries in ensuring food security is still not fully known. However, despite providing a low calorie diet, fish is often the most important source of dietary protein especially in less developed areas of the world where other sources of animal protein are scarce or expensive (FAO 2001). Studies in various developing countries show that 80-100 percent of aquaculture products from rural farm households are marketed, suggesting that aquaculture can also be considered as a cash-generating activity and thus an important indirect source of food security (FAO, 2003a). Thus, in addition to the nutritional advantages of increased fish production, aquaculture may bring the diversification necessary to provide a source of livelihood and foreign exchange essential for household and national food security (Sverdrup-Jensen, 1999; Williams, 1999; DFID, 2003).
Box 1: Aquaculture development in sub-Saharan Africa
Trout breeding in high altitude cold water was introduced in South Africa between 1859 - 1896 and in Kenya and Madagascar towards the end of the 1920s (Vincke, 1995). The first successful production of tilapia in ponds (mainly Oreochromis niloticus) occurred in the Democratic Republic of Congo in 1946 (Vincke, 1995). Pisciculture techniques were introduced subsequently from Europe to a number of African countries and fish farming therefore developed rapidly such that by the end of the 1950s there were about 300 000 ponds in production (Satia, 1989; Machena and Moehl, 2001). Aquaculture development slowed dramatically at the end of the colonial era when resources became scarce (Aguilar-Manjarrez and Nath, 1998) and most ponds were abandoned because of low yield or as a result of political disturbances (Vincke, 1995). Aquaculture began to develop again in the late 1960s through increased technical assistance financed by multilateral and bilateral donors (Vincke, 1995; Aguilar-Manjarrez and Nath, 1998). The 1970s and 1980s witnessed numerous aquaculture development projects (Machena and Moehl, 2001) and in the 1990s commercial development and diversification allowed production to increase (Brummett and Williams, 2000). Aquaculture has become well established in a number of countries including Côte dIvoire, Madagascar, Malawi, Nigeria and Zambia (Machena and Moehl, 2001). More than 60 species of fish were farmed in sub-Saharan Africa in 2001, producing 62.4 thousand metric tonnes of aquaculture products valued at US$138 million (Fishstat, 2001).
Figure 1: Evolution of the total aquaculture production in the sub-Saharan Africa region (Fishstat 2001).