At Aliwal Shoal Scuba, you can almost feel the anticipation in the air. It’s an anticipation that has everything to do with the fact that winter is just around the corner, and one that increases every time the ocean gets another degree colder. Winter is a cause for celebration for many reasons. On the Shoal itself, the arrival of winter coincides with the arrival of the humpback whales, who migrate past our shores on their way to their breeding grounds in the warmer waters of Mozambique. It also heralds the return of the ragged-tooth sharks, who use our reefs as a mating site during the colder months. Most of all, though, our excitement has to do with the Sardine Run- a phenomenon that takes place on the east coast of South Africa every year between the months of June and July. We have taken an active part in the Sardine Run for many, many years, moving our entire operation from Umkomaas to Port St Johns in order to maximise our chances of catching the very best of the Sardine Run action. This year is no exception, and accordingly we will be running weekly trips to Port St Johns from June 28th to July 26th.
The Sardine Run is triggered by the spawning of billions of sardines in the cool waters of the Agulhas Bank, near the Cape. These sardines, which are more specifically known as the South African pilchard Sardinops sagax, can only tolerate temperatures of 21 C or lower. At the same time as the spawning, a corridor of cold water opens up along South Africa’s east coast, allowing the sardines to migrate or ‘run’ far further north than their temperature tolerance would usually allow. The sardines cannot stray outside the confines of this cold water corridor, and as such are restricted to shallow inshore waters that allow no room for escape from pursuing predators. The Run therefore constitutes easy pickings for both temperate and tropical marine predators, which gather in the wake of the fleeing sardines like lions in the wake of East Africa’s great wildebeest migration. In fact, such is the similarity between these two phenomenons, both in terms of predator action and in terms of sheer biomass, that the Sardine Run has earned itself the alternative moniker ‘the Serengeti of the Sea’.
The predators that arrive on South Africa’s east coast to take advantage of this sudden bounty are as numerous as they are diverse. They include birds, fish and marine mammals, with the two most notable indicator species of the Run being the Cape gannet and the common dolphin. These two species are always the first to find the isolated sardine bait-balls, and are the ones that we follow when trying to pinpoint the action for our divers. Once a bait-ball is found, divers can enter the water either on snorkel or on scuba to bear witness to the melee below the surface. The sardines are attacked from above and below by gannets, dolphins, sharks, and whales. The most common shark species seen on the Run are the bronze whaler, the dusky and the oceanic blacktip. The most common whale associated with the Run is the giant Bryde’s whale, although orcas have often been seen in chase of the sardines as well. Other potential sightings include bottlenose dolphin, Cape Fur Seals, and a plethora of Gamefish; and the humpbacks, whose migration takes place at the same time.
It takes a lot of patience and many hours spent at sea to locate these bait-balls, and as such we spend the whole day on the water during our Sardine Run trips. Our experienced skippers have the knowledge and expertise necessary to provide the very best chance of witnessing the Run in all its chaotic glory. The hours spent in search of the bait-balls are exciting in their own right, as we keep an eye out for humpbacks on the move, rare birdlife and super-pods of common dolphin numbering hundreds of individuals. If the conditions allow, guests can snorkel with these amazing cetaceans wherever possible. We offer packages that include all meals, equipment hire and accommodation in Port St Johns (otherwise known as the Jewel of the Wild Coast and well worth exploring in its own right). The Sardine Run is the highlight of the South African diving calendar, and something that we look forward to immensely every year. We can’t wait for June to arrive, so that we can go in search of one of the planet’s greatest natural events. If you’d like to find out more about joining us on our Sardine Run adventures, please get in contact via Facebook, or send an email to firstname.lastname@example.org