Why shoals of sardines swim to the KwaZulu-Natal coast during the winter months, remains a mystery. The spawning grounds for the South African sardines, Sardinops sagax lie off the Southern Cape coast. They breed from spring to early summer. Their eggs are simply released into the water, fertilized and left to drift off in the open ocean. The ocean currents carry most of the developing larvae westwards and northwards into the waters of the Atlantic Ocean along the West Coast.