This natural spectacle takes place almost every year on the eastern coasts of South Africa and Mozambique—the so-called “Sardine Run.” To this day, the reason why it occurs cannot be precisely defined. There are various scientific theories, but some of them contradict each other.
In some years, however, the Sardine Run is not observed. During these years, it was thought that the Sardine Run did not take place due to climatic conditions. But just because one cannot see it on the surface does not mean that the sardines are not migrating.