Nile tilapia is vital for food security and income generation in Uganda, serving as the primary fish species in aquaculture. However, production has stagnated in recent years, largely due to limited access to high-quality fish seed, leading to poor yields, despite increasing market demand. This challenge is further compounded by rising global temperature, which negatively impacts growth in both wild and farmed populations. This study investigates genetic variation in growth-related traits among Nile tilapia populations in Uganda, with the goal of enhancing growth performance and improving overall aquaculture productivity.
A total of 78 full-sib families of Nile tilapia were generated using a single-pair mating design in hapas (1 m × 2 m × 1 m), comprising 26 families from Lake Albert, 29 from Lake Victoria, and 23 from Lake Edward. All families were reared communally under uniform conditions for 143 ± 16 days to evaluate growth performance. At the end of the period, body weight, standard length, and total length were measured to assess phenotypic variance components and estimate heritability. A mixed linear model was applied, incorporating initial weight, batch, age, and stocking density as covariates, with restricted maximum likelihood (RML) used to estimate variance components.
All growth traits showed significant differences among the local Nile tilapia populations (p<0.05). Heritability estimates varied from low to high across populations (Table 1), indicating genetic variation in growth potential. Although the coefficients of variation for growth traits were not statistically significant (P>0.05), they ranged as follows: 35.5% to 36.3% for body weight, 11.8% to 12.3% for total length, 11.7% to 12.3% for standard length, and 35.6% to 36.2% for daily body weight gain.
The observed genetic variation and significant differences in growth traits among Nile tilapia populations highlight the potential for selective breeding to enhance growth performance and productivity in Uganda’s aquaculture sector.
Keywords: Nile tilapia, Growth performance, Heritability, Selective breeding, Aquaculture improvement