We spoke with Iván Pérez, PhD in Oceanography from the University of Concepción and professor and researcher at the i-mar Center at the University of Los Lagos, to gain a deeper understanding of how this climate system affects the industry.
What are the risks of this climate phenomenon for salmon farming?
The El Niño phenomenon poses a risk to salmon farming because fish are confined in warmer waters, which could lead to increased mortality if preventive measures are not taken. Unlike wild fish species, which can migrate to greater depths in search of cooler waters, farmed salmon have limited mobility and cannot escape rising water temperatures, increasing their vulnerability.
How does the arrival of El Niño become evident?
The climate phenomenon reaches Patagonia through changes in weather patterns and surface warming. The event is classified according to temperature anomalies, with an increase of 2.5°C to 3°C above average considered a “very strong” El Niño, similar to the conditions experienced between 2015 and 2016.
What happens to salmon following a sudden change in ocean temperature?
A very strong event raises water temperatures and could trigger harmful algal blooms (HABs). It could also lead to lower oxygen levels, as excessive warming reduces the water’s capacity to retain dissolved gases.
What other environmental factors can affect salmon?
In addition to El Niño, the Southern Annular Mode (SAM) must also be considered. The combination of a positive SAM and El Niño can create climatic conditions characterized by high solar radiation, drought, and reduced rainfall, further increasing environmental stress on salmon.
The SAM is a process involving winds that circulate around Antarctica. A positive SAM brings drier conditions to Patagonia, while a negative SAM brings increased moisture. The current combination of a positive SAM and El Niño creates a dry and challenging scenario for the region.
What recommendations are there for salmon farmers to avoid negative impacts on their operations?
The industry should be prepared for the worst-case scenario without relying on external or government support, as impacts in Patagonia can emerge with a delay of up to eight months following the initial warming near the Equator. The i-mar Center recommends maintaining current precautionary measures throughout the spring and the coming summer, and remaining on alert for six to twelve months. This includes keeping biomass transport vessels operational and ensuring that all mitigation systems are ready for immediate activation in the event of increased mortality.
