YALI Voices: Making Aquaculture Possible Using Simple Raised Fish Tanks

Contributed by Shadrack Kwadwo Amponsah (Ph.D., MGhIE, 2018 Mandela Washington Fellow)

In countries like Ghana, where agriculture is predominantly dependent on rainfall, local smallholder farmers are most vulnerable to the unpredictability of the weather in the face of global climate change. Whereas developing economies seek climate justice to mitigate the effects of the changing climate on livelihoods, researchers are exploring adaptation mechanisms to make agriculture sustainable. Ghanaian agricultural researchers are encouraging integrated farming as an economically and environmentally sound activity in food production and income generation.

The Crops Research Institute of the Council for Scientific and Industrial Research (CSIR), in collaboration with sister institutes (Water Research and Animal Research), the Ministry of Fisheries and Aquaculture Development, and the Brazilian Agricultural Research Institute (EMBRAPA), has since 2014 implemented the aquaponics-based food production system (AFS) project, which integrates crop production (especially the cultivation of vegetables and other common staple food crops) with the rearing of fish in simple raised tanks, poultry-raising, and small ruminant rearing. The objective of this integration is to ensure year-round food production for enhanced nutrition to the smallholder farmer while offering an attraction for the youth to venture into agriculture. The integrated food production system employs vermicomposting to ensure all organic wastes from the various units within the system are beneficially utilized. This ensures that soil fertility is well maintained for sustainable crop production.

The integration is such that the output of one unit is the input for another (Figure 1). In such a closed loop system, there is no waste, since everything is plowed back into the system, making the AFS environmentally friendly. The aquaponics system involves the channeling of effluent from fish ponds into a source of supplementary irrigation water for crop production. Vermiculture (rearing of worms) is used in the transformation of organic matter from crop residues and animal droppings into humus. The compost produced is used to improve the soil for crop production. Within the AFS system, there is no use of conventional fertilizers since all crops are organically produced using the rich compost from the vermicomposting. The result is abundant yields of a wide variety of commonly consumed vegetables, fruits and grains at low cost. This system of food production will be a major benefit to smallholders as it is highly efficient in its consumption of water and the conservation of soil fertility. The farmers will be able to produce throughout the year while conserving the already scarce resources of water and soil. This integrated approach to food production is a sure way to meet the Sustainable Development Goals (SDG 1&2) of no poverty and hunger.

Figure 1: Integration of the various units within the AFS

The AFS in its implementation is very flexible, in that it is not required that a farmer start or set up the food production units all at once. The farmer could decide to start each of the units individually and add up to get the full complement of the integration that the project recommends. However, it is expected that the fish pond comes first. Existing fish culture systems like the dug-out and cages had long been viewed as an impossible option or area in which to venture for smallholder farmers because of its associated skilled labor and financial requirements. Technological advancement through research has brought a new system of fish culture in simple raised tanks that has made it possible to rear fish even in the backyard with minimal skill requirement. The fish pond is constructed using locally available materials and expertise, thereby making it relatively affordable, compared to existing systems.

Figure 2: The rectangular AFS fish tank setup

This fish pond, unlike existing types, is a raised tank with a rectangular dimension of 4m × 3m (Figure 2) or a 4.3 meters diameter for the circular type (Figure 3), each with a depth of 0.9m. The pond could take a maximum of 300 tilapia fingerlings and 1,000 catfish fingerlings (20g) to be fattened to a size of at least 0.3 kg and 1.0 kg, respectively, for a period of 4 to 6 months.

Figure 3: The circular AFS fish tank design

Presently, there are only two locations in Ghana where the project has been fully established with all the various components to serve as learning hubs or technology dissemination centers; on-station at the CSIR-Crops Research Institute, Fumesua, Ashanti region, and at the Institute’s out station in Aiyinase, Western region. Since 2015, training has been organized for over 600 farmers, entrepreneurs and agriculturists nationwide as part of the technology dissemination agenda. Training efforts have currently yielded over 50 adopters of the fish pond technology across the country (a majority in the Ashanti region) with about 30 percent practicing the integration with their own food production systems.

The views and opinions expressed here belong to the author and do not necessarily reflect those of the YALI Network or the U.S. government. YALI Voices is a series of podcasts, videos and blogs contributed by members of the YALI Network.