The annual Sardine Run that occurs along the east coast of South Africa brings with it all kinds of predators that feast on the millions of sardines. The sardines spawn in the Agulhas Bank’s cool waters, then follow the current of cool water, that heads north up to Mozambique, where it then heads east into the Indian Ocean. The shoals often stretch over a distance of more than 7 km, are about 30 m deep, and about 1.5 km wide.
The Cape Gannet (Morus Capensis) is usually the first sign of the approaching shoal, with huge numbers of these birds diving into the water from the air, to feed on the sardines. The huge flock of diving Gannets, can be seen from quite far away.
Whales that can be seen during the run are Humpback Whales, Minke Whales and Brydes Whales. The main predators that enjoy the feeding frenzy that goes along with the run are dolphins, birds, game fish, penguins, seals, whales and, of
course, sharks. Shark nets that provide protection for bathers, are removed prior to the sardine run occurring, thus giving way to many sharks to join in the sardine predation. It is also done to prevent injury or death to the increased number of sharks following the run.
The shark that is primarily seen preying on the sardines is the Bronze Whaler Shark, also known as the Copper Shark. They join the sardine run in large packs every year. Other shark species that have been recorded as preying on the sardine run are Black Tip Sharks, Dusky Sharks, Ragged Tooth Sharks and Bull Sharks.
These predators join and follow the sardine run, from around the coast of East London, all the way up the east coast,
passing Durban. Aliwal Shoal, which is home to a variety of sharks, is about 5km offshore from the Kwazulu-Natal coast,
giving the sharks that reside there, easy access to the passing sardine run.
Dolphins, mostly the Common Dolphin (Delphinus Capensis), estimated to be about 18 000 strong, seem to do
the most work, rounding up the sardines into bait balls, varying in size from 10 to 20 meters in diameter, and can extend to a depth of about 10 meters. Once the sardines are rounded up, it makes for easy preying for the sharks. The sharks rush into the ball of sardines, eating as many as possible. Copper Sharks can consume up to 20 sardines at a time, in one big gulp. These bait balls survive at most, for about 10 minutes.
All these factors make for a truly amazing spectacle to behold. If at all possible, put the Sardine Run on your calendar, for an unforgettable experience.