THE GREATEST SHOAL ON EARTH
A furious, frenzied, underwater circus awaits intrepid divers who venture south for South Africa’s celebrated sardine run
“Death comes from all sides; from the sky, thousands of gannets dive into the school while the dolphins charge from the left, from the right, from beneath. Hundreds of bronze whalers, dusky and sand tiger sharks patrol the lower and outer realm, making occasional forays through the centre of the fish ball. Lurking below, unseen in the darkness of depths, five, 16-metre, 50 ton hotblooded predators rise upwards or sideways through the silvery shoal. Some sardines escape the whale’s charge by hurling themselves into the air, but their reprieve is but momentary as hundreds of predators are waiting to pounce on the escapees.” – Michael Aw, Explorer
The sardine run happens in the winter months from May to August, when millions of sardines, Sardinops sagax, leave the southern Cape waters of the Agulhas bank, to follow the cold, nutrient-rich body of water up the African coast to Kwazulu Natal. This belt of cold water in which the sardines travel is formed by the winter storms of the Cape, pushing the cold water north, while the warm Agulhas current that runs from the north to the south traps this cold water against the coast. Along the Transkei coast, the continental shelf pushes this cold water into its narrowest strip, concentrating the sardines and the predator load at its highest, creating the conditions for some high-octane action. Film crews, amateur photographers, and ocean enthusiasts all flock to Port St. Johns, Mbotyi and the surrounding areas to get a space on the charter boats that provide the best opportunity for witnessing this event.
Port St. Johns is a small, rustic town on the Wild Coast, a 250-kilometre stretch of coastline which gained its name from its inaccessibility and treacherous shoreline. Although this makes for risky surf launches on the semi rigid inflatables, and hair-raising adventures at the crack of dawn with high-end camera equipment, it makes it all worthwhile when your skipper drops you right in the middle of a feeding frenzy. From the skies to the depths below, predators line up to feast on the proteinrich baitfish.
SCHOOLING TO SURVIVE
These bait balls form when common dolphins separate a small pocket of fish from the main shoal, and push it up to the surface. The dolphins circle the bait ball for a while, blowing bubbles from below, herding the little fish into a tight swirling mass. They then dart through together in a group to grab as many fish as they can. They will repeat this pattern over and over, until the last sardine is gone. These sardines know, if they lose the group, they are an easy target.
The sharks on the other hand, have no such skilled and organised feeding plan in place. Their strategy is to simply swim through the bait ball, mouth agape, consuming as many mouthfuls of fish as they can. That is why we, as divers, never hang around inside the bait ball! Sometimes that proves difficult, as the sardines often try to use divers as protection.
BATTERED FROM ABOVE
Once the bait ball is visible to the birds in the air, Cape gannets bombard it from every angle, raining down like bullets. When each gannet hits the water, it’s like an explosion below the surface, and one of my favourite moments of the sardine run. These gannets, with their wings folded back, tight as torpedoes, can easily dive to a depth of 15 metres to reach the bait ball, and sometimes grab up to three fish, before returning to the surface. Gannets have been recorded hitting the water at more than 85 kilometres an hour, which has often made me wonder: should I be diving with a helmet…? My most memorable gannet picture was taken at the end of a long day at sea. We had less than five minutes left in water, before our skipper was going to pull us out because it is unsafe to go back through the breakers in the dark and the light was fading. The evening light had turned to a magical golden glow and the shallow bait ball was moving slowly in the shimmering light. I was waiting patiently for something to happen, when suddenly a gannet hit the water right in front of me and opened its wings as he grabbed a fish out of the fleeing shoal. I knew I had captured something special.
IT’S A WHALE OF A TIME
Humpback whales are often seen in the area, cruising along on the surface in family groups. They are in fact
not here for the sardines, but are migrating northwards to the warm Mozambique and Madagascan waters to have their calves. This makes for an added bonus, when searching the open ocean for any bait ball action. However, a whale that is definitely there for the sardines is the seldom-spotted Bryde’s whale, the largest of the sardine run predators. In 2010 I was lucky enough to come face to face with one of these magnificent animals, while filming one of the largest bait balls I’ve ever seen. I was about eight metres underwater, when suddenly the bait ball parted and, heading directly for me, was a 12-metre Bryde’s whale. I had to make a move, because he had no intention of avoiding me. He barely missed me as I moved upwards, pulling my fins in tightly underneath me. What a spectacular sight it was later in the day, when I managed to film him, lunging through the bait ball from below. Being surrounded by masses of sharks, huge pods of dolphins, whales, game fish and thousands of seabirds, all feeding off the giant shoals, is surely an experience every diver hopes for. We all dream of that perfect bait ball in clear blue water, with endless action; a vision that keeps us coming back year after year. SDOP
1. A common dolphin snatches a struggling sardine from a small shoal that they have chased up to the surface, in the fading evening light off Port St. Johns Image © Mark Van Coller
2. A large pod of bottlenose dolphins having fun in the large breaking waves, as they make their way northwards up the coast Image © Mark Van Coller
3. Two humpback whales, migrating up the coast from the Southern Oceans, to the warmer Mozambican waters. They are not here to feed on the sardines but just happen to coincide with the sardine run, when doing their annual migration Image © Mark Van Coller
5. A Cape gannet dives into a small school of sardines, as the last rays of sunlight hit the water Image © Mark Van Coller
5. A shark dashes through a giant baitball to get a mouthful of sardines, one of the many predators attacking this shoal from all sides Image © Mark Van Coller