‘El Niño’ Causes A 14 Pct Drop In Tuna Populationff

Source: Notimex

A study by a team of scientists from the Center for Atmospheric Science (CCA) of the National Autonomous University of Mexico (UNAM) revealed that the dynamics of the tuna stocks is linked to the oceanic phenomena El Niño and La Niña (atypical heating and cooling in tropical waters).

During the research project entitled “Climatic effects on the pelagic tuna abundance”, scientists found that the effect of El Niño causes a decrease of up to 14 percent in the tuna population, said the head of the CCA’ s Department of Bioclimatology, Walter Ritter Ortiz.

However, they noticed that -after this oceanographic condition- a rejuvenation of the population takes place, which leads to the formation of recovery loops.

Ritter Ortiz noted that the Eastern Pacific Ocean (EPO) is the world’s most productive area of yellowfin tuna, benefitting over 20 countries and valued at millions of dollars. It is the place where all atmospheric phenomena are climatically formed in the Northern Hemisphere.

If there is a major event, such as the one that took place in 1982 when El Niño caused an increase of 40 percent of fish stocks, the fish schools rejuvenate and remain above their proportions.

Not only the temperature but also the presence of tuna can be used to predict the presence of El Niño phenomenon, according to Ritter Ortiz: “We’ve studied it, however from the point of view of a new physics and mathematics called Analysis of Complex Dynamic Systems.”

This process is also known as the Chaos Theory Dynamic Systems with which the scientists have come to determine the stock rejuvenation and also predict future events. It produces a better representation of the natural phenomena than the traditional formula. The researchers argue that “the classical methods are necessary but not sufficient”.

According to these experts, if these methods are followed and are complemented with the existing ones, the benefits will be very important, since the populations could increase up to 40 percent.

Data from the Inter American Tropical Tuna Commission (IATTC) indicate that between 1 January and 30 October, 2011 a total of 474,552 tons of tuna was caught, 17.7 percent more than in the same period last year, when 402,868 tons were captured.

Until 30 October, the Mexican vessels had caught 118,613 tons of tuna, the Ecuadorian fleet 171,140 tons, the Panamanian vessels 48,558 tons and the Venezuelan 40,659 tons, among others.