Predators
Dolphins (estimated as being up to 18,000 in number, mostly the Common Dolphin Delphinus capensis, but also the Bottlenose Dolphin Tursiops aduncus) are largely responsible for rounding up the sardines into bait balls. These bait balls can be 10–20 metres in diameter and extend to a depth of 10 metres. The bait balls are short lived and seldom last longer than 10 minutes. Once the sardines are rounded up, sharks (primarily the Bronze Whaler, but also Dusky Shark, Grey Nurse Shark, Blacktip Shark, Spinner Shark and Zambezi Shark), game fish (including Shad/Elf a.k.a. Bluefish, King Mackerel, Garrick, Geelbek and Eastern Little Tuna) and birds (like the Cape Gannet, cormorants, terns and gulls) take advantage of the opportunity.
Cape Fur Seals follow the shoals up the Eastern Cape coastline as far as Port St Johns.
Read more about this topic: Sardine Run