Closing the yield gap: increasing survival and production efficiency in smallholder farms of

In this project we will investigate opportunities to reduce the yield gap in Nile tilapia farming and develop solutions that can be used in breeding programs aimed at Nile Tilapia production by small holder farmers. Currently many small- and medium sized tilapia farms in developing countries underperform in terms of feed efficiency (FE), despite the use of genetically improved strains of tilapia such as GIFT. FE under small holder conditions is primarily determined by mortality and individual feed efficiency, both of which are strongly influenced by the production environment. In this project we will investigate the ontogeny of growth and survival over time in contrasting, commercially relevant farming environments. The research hypotheses are: (1) recording survival at different stages during fingerling rearing and grow-out can be used to improve survival by selection. (2) genotype by environment interaction is substantial for growth and survival, when measured from fingerling stage onwards. (3) selection on growth rate and survival under the right environmental conditions will improve feed efficiency and economic profitability. This project will yield important information for the development of breeding programmes tailored towards Nile Tilapia production on small- and medium sized farms. The proposed project is expected to impact smallholders in the following ways: i) The yield gap will be reduced by selecting in the right environments. ii) The yield gap will be reduced by selecting on the right traits. iii) The income for smallholder farmers will increase due to a reduced yield gap.