Sardines overcome a long way more than 1000 km long, forming a shoal 1.5 km wide, 15 km long and 40 meters deep. It is curious fact that marine predators such as whales, sharks, dolphins, seals and birds swim after a shoal of sardines.
The Largest Fish Shoal on Earth

Sardines prefer cold water near the southern and western shores of South Africa.
Every year from June to July, sardine shoals migrate to the eastern coast of South Africa. It is there warm and cold water currents meet: Mozambique and Benguela.