Scientists are sampling rainbow trout in rural and high-altitude communities to support its genetic analysis. (Photo: R. Nahuelpi/ University of Chile)
Latin America's rainbow trout farmers are using nuclear-derived techniques to detect deadly disease outbreaks earlier and breed more resilient fish, helping to boost food security and protect livelihoods.
Supporting Early Disease Detection
One of the most serious threats to rainbow trout is the infectious pancreatic necrosis virus (IPNV), which causes a highly contagious disease that can lead to significant fish mortality.
In severe IPNV outbreaks affecting fry and juvenile fish, mortality can exceed 50% and, in extreme cases, may approach 90%. When outbreaks occur, farmers may lose a large part of their production. As trout is a nutritious food source for many rural and high-altitude communities, a loss in production threatens both livelihoods and food security.
Early detection of IPNV was previously difficult due to limited diagnostic capacity, but with IAEA support, scientists are now using nuclear techniques to detect pathogens earlier and identify genetic traits linked to disease resistance.
To tackle IPNV, the IAEA equipped laboratories and trained specialists in nine countries across the region - Argentina, Brazil, Chile, Ecuador, Mexico, Panama, Peru, Uruguay and Venezuela - through an IAEA technical cooperation project under the ARCAL agreement with the support of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture .
The project aimed to move from reacting to the disease to preventing it through science and cooperation.
IAEA training in nuclear-derived techniques including advanced DNA analysis, genetic sequencing and molecular diagnostics enabled scientists to gain practical tools to better understand the virus and the fish.
Trout farming is a growing sector in Latin America, particularly in Chile and Peru. (Photo: University of Chile)
Breeding More Resilient Fish
IAEA capacity building gave scientists the skills to analyse the genetic characteristics of rainbow trout populations and to identify molecular markers linked to genetic resistance to IPNV. This breakthrough allows producers to choose fish that are genetically resistant to the virus, offering a powerful opportunity to enhance the resilience of rainbow trout populations in the region.
"Evidence shows that selection based on this marker can improve survival by approximately 1.2% under a conservative scenario," said Carla Bravo de Rueda, Animal Health Technical Officer at the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture. In concrete terms, this means roughly 1.2 additional tonnes of fish for each 100 tonnes produced per generation, depending on marker frequency and its progressive incorporation into breeding programmes through selection.
"Because trout reach market size after just a few years, these 1.2% gains from each generation accumulate quickly - adding many tonnes of extra fish that farmers can sell," she added.
Even small improvements in fish survival can make a significant difference in aquaculture. Healthier, more resilient fish mean fewer losses, more stable production and better incomes for farmers. For countries, it supports economic growth and strengthens food systems, ensuring communities' access to nutritious food that contributes to better health.
Breeding programmes were strengthened in Chile and established in Brazil, laying the foundation for sustained regional development. Instead of relying only on experience, breeding decisions can now be guided by science, with fish selectively bred for resistance to the virus in their local conditions.
"This project has improved rainbow trout breeding by using advanced genetic analysis to identify and confirm traits linked to resistance to IPNV," said Jose Manuel Yanez Lopez, Dean of the Faculty of Veterinary and Animal Sciences at the University of Chile. "These advances pave the way for more precise marker-assisted selection strategies, helping to improve survival rates, enhance breeding efficiency and strengthen the genetic resilience of aquaculture stocks."
In Chiloé, Chile, scientists are working with the aquaculture industry to improve trout breeding programmes. (Photo: David Tapia / University of Chile/ INVASAL)
Harmonizing Regional Practices
From small family farms to large commercial operations, rainbow trout is produced under different systems in Latin America. This diversity reflects the richness of the region, but also its challenges: unequal access to technology, limited infrastructure and dependence on imported broodstock in several countries.
The project is harmonizing IPNV diagnostic protocols, assessing the genetic variation in rainbow trout populations, promoting selective breeding of virus-resistant fish and reducing technical gaps across countries.
Producers in the region are now better equipped to detect and respond to this disease, while stronger collaboration between laboratories, authorities and producers has created a regional network that supports continuous innovation knowledge exchange and resilience in the aquaculture sector.
Trout is rich in high-quality protein and omega‑3 fatty acids, which support heart health, brain development and overall wellbeing. (Photo: Carolina Araya/ University of Chile)
