It's sometimes called the 'Greatest Shoal on Earth', and for good reason with hundreds of millions of small fish moving around in giant bands causing a feeding frenzy wherever they go. A new study in the journal 'Science Advances' by South African and Australian scientists explains why the sardines run.
Every year in June or July along the KwaZulu-Natal coast an incredible spectacle plays out. Hundreds of millions of Sardines move in a band -- often more than 7km long, 1.5km wide and 30 metres deep -- up the coast in what is commonly known as the annual "Sardine Run". Now, a recent study using genomics explains exactly why Sardines 'run' at all.
The study in the journal Science Advances was conducted by South African and Australian scientists who tested the hypothesis that the Sardine Run represents the spawning migration of a distinct east coast stock adapted to warm subtropical conditions.
The results of the study showed that there exist two distinct sardine populations in South Africa; one in the cool-temperate west coast (Atlantic Ocean) and the other in warmer east coast waters (Indian Ocean). Each regional population appears adapted to the temperature range that it experiences in its native...