Every year between May and July, billions of sardines migrate northward along the KwaZulu-Natal coast of South Africa in what is widely described as the greatest shoaling event on earth. The run stretches for kilometres, is visible from the air, and triggers a feeding frenzy involving hundreds of species of predators — dolphins, sharks, gannets, game fish, and whales — in a spectacle that has no equal in the fishing world.
The Science Behind the Run
The sardine run is triggered by the formation of a cold water current (below 21°C) along the Transkei coast in late April and May. Sardines are cold-water fish that cannot survive in the warm Agulhas Current water north of East London under normal conditions. When the cold tongue extends far enough north, it creates a corridor that the sardines can travel through. They are moving to spawning grounds — the driving force is reproductive, not nutritional.
What Predators Are Present
The bait ball creates an extraordinary concentration of predators. Common dolphins coordinate to herd the sardines into tight balls near the surface. Bronze whaler sharks and dusky sharks slash through the baitball from below. Cape gannets plunge-dive from above at 90km/h. And game fish — garrick, kob, shad, and occasionally GT — target the edges of the baitball from all directions simultaneously.
Timing
The run typically peaks between June 15 and July 20 in most years, though timing varies by 2–4 weeks depending on water temperatures. The Port St Johns to Port Edward stretch of the Wild Coast consistently produces the most intense activity. Monitor sea surface temperature data — when the cold tongue reaches above 29°S, the run is imminent in that area.