Project title: Closing the yield gap: increasing survival and production efficiency in smallholder farms of Nile tilapia


Project team: Prof. Dr. Hans Komen (WU), Dr. Han Mulder (WU) and Prof. John Benzie (WorldFish)


PhD student: Samuel Bekele Mengistu


Project Start date – End date: 1-2- 2016 to 31-1- 2020


Summary of objectives

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 genetic improvement of farmed tilapia (GIFT) strain. 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 objectives of this project are to investigate whether:

1.     recording genetics of 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, and

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:


1.     The yield gap will be reduced by selecting in the right environments.

2.     The yield gap will be reduced by selecting on the right traits.

3.     The income for smallholder farmers will increase due to a reduced yield gap.





Academic background of Samuel Bekele Mengistu


Samuel Bekele Mengistu was born on 7th of Febbruary 1977 in Shone, Ethiopia. He graduated in General Agriculture in 1997 from Awassa College of Agriculture, Hawassa University. After his graduation he joined Ministry of Agriculture and served as Development Agent until he joined the same college for his Bachelor degree in Animal Production and Rangeland Management in 2002. After he received his BSc in 2005 he was employed as a graduate assistant in the same university. He received scholarship from the Norwegian State Educational Loan Fund (Lånekassen) to pursue his MSc in Aquaculture in Nowegian University of Life Sciences and graduated with MSc in 2010. From August 2012 until January 2016 he worked in Awassa College of Agriculture, Hawassa University as a lecture. In February 2016, he received scholarship from Koepon Foundation and joined Wageningen University for his PhD.