The Long-beaked Common Dolphins of Algoa Bay
By Lloyd Edwards

1. News

These charismatic animals are the ones which make the “sardine run” come alive. As per previous posts, easterly winds cause the upwelling events which bring nutrients and plankton spores to the surface. Plant plankton feeds the animal plankton which in turn feeds the baitfish and draws all the apex predators into Algoa Bay.

The baitfish are fast moving and need a speedy predator to locate, stop and then encircle a school of anchovies, sardines, saury, mackerel or red-eye round herring. Here is where the Long-beaked common dolphins come into the picture. They are masters at the game and hold the shoal of high energy protein in check. This allows the Cape gannets, African penguins, South African fur seals other seabirds, game fish and sharks to pick off fish from the edge of the ball. In the distance, the trained eye will notice the blows of the Bryde’s whale moving closer. They use low frequency sound waves to locate the stationary bait ball and home in on it, taking what is left in one foul swoop.

Common dolphins are the most widely distributed of all the dolphins, except for their cousins the killer whales, who are found in all oceans around the globe. Commons are normally found from 10km offshore and further, which is why they are seldom seen from the shores of Algoa Bay. It is only when the baitfish are in the bay that they come in so close. Scientists estimate that there are around 20 000 along our coast, although I would say that there are plenty more. They will probably be around for the duration of our “sardine run” which lasts until June.

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