We spoke with Aquiles Sepúlveda, Director of the Fisheries Research Institute, to gain a deeper understanding of how this climate event is affecting the industry.

What are the first signs in the ocean that precede the El Niño phenomenon?

In December last year, heat waves occurred that were not, strictly speaking, an El Niño event, but they had a significant impact along the northern and north-central coast of Chile. These conditions caused ocean waters to shift in a manner similar to an El Niño event. Then, in April, what is known as an initial variant of El Niño, or Coastal El Niño, developed, with a significant warming of the Peruvian coast, reaching temperatures up to 7°C above normal. This generated a wave that moved from north to south, significantly influencing both weather patterns and fisheries.

How does the El Niño phenomenon manifest itself in the ocean once it begins?

As I mentioned, one of the main changes that occur during this phenomenon is the increase in ocean temperatures, which causes several species to move southward, particularly jack mackerel. They also move to greater depths, where they find higher oxygen levels and temperatures more suitable for their survival.

What happens to jack mackerel when it moves south?

The El Niño event drives warm waters southward, triggering the migration of a portion of juvenile fish that would normally remain in tropical waters. As a result, fisheries begin catching smaller individuals, which is a critical factor to consider, as these fish are less than one year old and many have not yet reached maturity in size.

What are the main impacts of an event of this magnitude on the region?

It is likely that the event will continue to have consequences through the spring and summer of this year and into the following year, with a “Super El Niño” event, as warned by international agencies. Its magnitude is still within the forecast range, but current projections point to a significant event. Therefore, we cannot yet expect ocean temperatures and species’ habitats to return to normal.

What benefits does jack mackerel gain from this climate phenomenon?

The El Niño phenomenon creates favorable conditions for jack mackerel to produce more eggs in the ocean during the upcoming summer, or even as early as November, when spawning occurs. This increases the likelihood of favorable spawning conditions and juvenile survival. Following an event of this magnitude, jack mackerel are likely to show strong juvenile recruitment into the fishery, helping replenish the population through the addition of new adults.

What species enter the fishery following an El Niño event?

Mackerel could provide an important resource for fisheries in northern and north-central Chile. While its availability will depend on its distribution and accessibility to the fishery, it could be a viable alternative to temporarily offset the reduced availability of key species such as jack mackerel.