Disease & heat resistance

Realized gains in survival from divergent selection in Nile tilapia validated under laboratory and field conditions

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Abstract

The intensification of aquaculture production has increased vulnerability to infectious diseases and environmental stressors, emphasizing the need for resilient genetic improvement strategies. In Nile tilapia (Oreochromis niloticus), survival at harvest is a key determinant of profitability. Economic analysis from field data collected in the Philippines indicated that every 1% increase in fish survival at harvest resulted in approximately 1.29% higher net profit for farmers. To address these challenges, a genetically selected Streptococcus-resistant Nile tilapia strain was developed and commercially released in 2020, demonstrating 30% higher survival (pStreptococcus, Flavobacterium, and Aeromonas pathogens. Kaplan-Meier survival analysis was used to compare cumulative mortality between genetic lines, with differences assessed by the log-rank test, revealing that the Robust Line exhibited relative percentage survival (RPS) of 22%, 12%, and 13% against Streptococcus (p0.05), and Aeromonas (p, respectively, compared to the Growth Line. By Generation 6, replicated common-garden trials under commercial pond and cage production systems in the Philippines, following BFAR-recommended stocking densities and management and feeding practices, demonstrated 20-60% higher survival at harvest of the Robust Line compared to the Growth Line under high disease and environmental stress conditions. These findings confirm that combining selection for specific pathogen resistance with general survival can substantially accelerate genetic gains in survival, enhancing both productivity and sustainability in commercial Nile tilapia farming.

Keywords: 2026

How to Cite:

Joshi, R., Skaarud, A., Pineada, T. & Alvarez, A., (2026) “Realized gains in survival from divergent selection in Nile tilapia validated under laboratory and field conditions”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2283843. doi: https://doi.org/10.31274/wcgalp.23523

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