Small Fish Matters: Improving the nutritional value of tilapia aquaculture in Kenya

About the project

UK-registered Partner: University of Stirling – David Little
Africa-registered Partner: Victory Farms Ltd – Steve Moran

Smallholder tilapia cage farmers in Sub-Saharan Africa often struggle with cash flow during the production cycle of rearing adult tilapia. Particularly towards the end of the cycle, before sales income is generated, feed costs (which can account for 70-90% of operational costs) exponentially increase with larger fish biomass. Thus, a collaboration between Victory Farms, the University of Stirling, and Tunga Nutrition trialled alternative production models to improve cash flow for smallholder tilapia cage farmers.

This trial compared higher stocking densities (3 versus 6 kg/m3) and partial harvest strategies. As partial harvesting aims to produce a larger distribution of smaller sized fish, the team also conducted a market survey to determine the demand for smaller fish. We found that (1) partial harvesting had no effect on survival or growth; (2) increasing stocking density had the best financial and technical results; (3) double stocking without a partial harvest yielded the lowest environmental impact; and (4) there is a large rural demand for smaller sized fish.

Although the total economic margins are lower and the environmental impact higher, using higher stocking densities and partial harvesting strategies or shorter cycles to produce small tilapia could be a viable solution for farmers to address cash flow constraints. Furthermore, lower-income consumers would benefit from increased availability of smaller (i.e., more affordable) tilapia, which the project found to be more micronutrient dense.

This project has developed a production calculator with an accompanying manual and instructional videos, freely accessible here.