This week’s blog post comes once again from the Wild Coast in South Africa’s Eastern Cape. The annual sardine migration that takes place here is happening as I write, so I thought I would describe some of the major predators that take part in this wildlife phenomenon.
The sardines are only small fish, but they occur in large numbers. The sardine shoals attract the attention of a great variety of predators. Dolphins, whales, seals, fishes, sharks and birds all hunt the sardines.
Perhaps the most visible of all the hunters are to be seen flying over the ocean in search of the sardines. These are Cape gannets. Strikingly marked, long-winged and graceful fliers, these birds gather in flocks and launch diving attacks into the sardine shoals. They form wheeling, screaming flocks of hundreds of birds, and these feeding flocks can be seen from a long distance away. Some of the other bird species that can be seen with the sardines are white-chinned and sooty petrel, yellow-nosed albatross, kelp gull and swift tern.
Marine mammals like seals, dolphins and whales hunt the sardines from below the water’s surface. Bottlenose dolphins and common dolphins are two species that take full advantage of the massive food source that the sardines provide. The bottlenose dolphins are larger, heavier and darker in colour than their cousins. Common dolphins are smaller, more agile, and typically take to the air when chasing ***or*** feeding on sardines more often than their bottle-nosed relatives. At times they force the shoals to the surface, and into tight, defensive, baitball formations. The sardine run provides some of the best viewing opportunities of both these types of dolphin.
Bryde’s whale is another predator that hunts the sardine shoals. Reaching over 10 metres in length, these whales seldom breach and are difficult to observe from the surface.
Although hump-backed whales are not known as major predators of the sardines, they are often to be found in the midst of the feeding frenzies.
When you add to this list of predators the bronze whaler shark, to name but one of many shark species that hunt the sardines, as well as many types of predatory fish, you get some idea of the spectacle that the annual run provides.
The action that happens around the sardine run can be seen from the shoreline *or* from a boat, and it is fast becoming a prime attraction for divers from all over the world.