Every year between the months of June and July, the east coast of South Africa is affected by a rare type of fever. Keen eyes scan the distant horizon for signs of life; while local radio stations schedule daily updates that provide information on one of the largest natural phenomena on the planet: Sardine Run.
The largest shoal on earth
The Sardine Run involves the annual migration of billions of Sardinops sagax , more commonly known as sardines or South African sardines. He has appeared in countless documentaries, including the BBC ‘s Nature’s Great Events; and has been the subject of extensive research. Despite this, very little is known about the mechanics of the Race, or why it happens in the first place.
What is certain is that the Race begins each year after huge schools of sardines spawn in the icy waters of the Cape’s nutrient-rich Agulhas Bank. After spawning, most sardines move north along the west coast of South Africa, where the waters are cool throughout the year. Conditions here are perfect for sardines, a kind of cold water that can only tolerate temperatures below 70 ° F / 21 ° C.
The east coast of South Africa, on the other hand, is washed by the much warmer Agulhas Current that flows south. However, each year between June and July, the cold Benguela Current pushes north from the Cape, creating a narrow channel between the shoreline and warmer water offshore. In this way, some of the sardines from Banco Agulhas can travel up the east coast to KwaZulu-Natal.
The fish move on large sandbars, locked in the shoreline by their instinct to seek safety in numbers and their inability to cross the barrier between the Benguela and Agulhas currents. Sometimes these shoals can measure up to 4.5 miles / 7 kilometers in length and 100 feet / 30 meters in depth, and legend has it that some are even visible from space.
Sardine race predators
Inevitably, the arrival of such an incredible influx of food attracts countless marine predators. Of these, the two most commonly associated with the Sardine Run are the Cape gannet, a beautiful cream-colored seabird, and the common dolphin. These two species are specially adapted to be able to find the schools first. Therefore, they act as a reliable indicator of sardine action for people and predators alike.
Once the dolphins locate the sardines, they work in conjunction with the gannets to raise the fish, separating them into smaller schools known as bait balls. Then the party begins, with birds and dolphins collecting the harassed sardines at will, attracting other hunters in the process. Typically these include copper sharks, bottlenose dolphins, and Bryde’s mighty whale, which often consumes entire bait balls in one bite.
Humans also eagerly anticipate the bounty of Sardine Run. While fishing fleets are busy on the high seas, locals living along the coast use purse seines to catch thousands of sardines as they enter the shallow waters in search of food. The survivors are believed to release their eggs into the warm waters off KwaZulu-Natal, drifting south to the Agulhas Bank, where they hatch the following year.
Experiencing the Phenomenon
The best way to experience the Sardine Run is from the water and, in fact, it has become a bucket list event for diving enthusiasts and underwater photographers. There’s nothing like the adrenaline rush of watching a bait ball get depleted by sharks and dolphins in front of your eyes, and you don’t have to have a scuba certification to do it. Many operators also offer freediving or snorkeling trips.
For those who don’t want to get wet, much of the action can be seen from above the waves. The Sardine Run coincides with South Africa’s annual humpback whale migration, and boat trips offer the opportunity to enjoy whale acrobatics while keeping an eye out for dolphins and seabirds. On land, beaches like Margate, Scottburgh and Park Rynie become a hive of activity every time the sardine shoals pass.
* It should be noted that while the sardine race is traditionally held every year between June and July, a combination of factors including climate change and overfishing have made the race less and less reliable. Those planning a trip around the Race should be aware that sightings are not guaranteed, and that activity varies greatly from year to year.
This article was updated and rewritten in part by Jessica Macdonald.
