Although we find tuna in fish farms all year round, the festivals that are organized around tuna in the Basque Country are all in the summer. Tuna have long migratory routes, although they are mainly located in two parts of the world, the Mediterranean and the Gulf of Mexico.

Whether born in the Mediterranean or in the Gulf of Mexico, tuna trees (Thunnus thynnus), when they reach maturity, leave their places of birth and move towards the Atlantic, and whether they are born in the Mediterranean or in the Gulf of Mexico, they mix and live together until they reach the age of reproduction. A

team of researchers from several US universities, led by Jay Rooker and Barbara Block, has studied the collection of substances called otolites of tuna in the inner ear. The amounts of carbon and oxygen found in it indicate with great certainty the place of birth. Thus, it has been known that more than half of the tuna studied in the waters of the Americas were born in the Mediterranean.

Therefore, it is concluded that the tuna populations of the Gulf of Mexico and the Mediterranean are related and if there is overfishing in one, there will also be a decrease in the population in the other. The importance of this news is great, because at the moment there is an intense debate between those who want to fish and those who do not.