An outbreak of Thalassiosira pseudomicronus has caused a large-scale salmon trout mortality event in the Los Lagos region of Chile. Over 1,500 tons of fish have died, with Salmones Austral being the most affected. The outbreak has expanded, affecting 28 breeding centers and resulting in 913.5 tons of dead biomass. Authorities are conducting ongoing algae testing and monitoring the implementation of emergency plans by affected companies.