Sardine Run Part 4, Killer Whales
By Lloyd Edwards

It is not often that killer whales make their appearance during the sardine run, but when they do, it brings the house down! Remember that the whole process starts off with the upwelling of cold nutrient rich water. This in turn feeds the phytoplankton (plant) which feeds the zooplankton (animal). These trophic levels are defined as “each of several hierarchical levels in an ecosystem, consisting of organisms sharing the same function in the food chain and the same nutritional relationship to the primary sources of energy”. 

 

The next trophic level are the baitfish, which consume both phyto and zoo plankton. These in turn are fed upon by a whole host of predators namely, African penguins, Cape gannets, cormorants, fish, seals, dolphins and whales. The killer whales in turn feed on these predators, making them the absolute apex predator in the sea. It was so amazing to have observed all the different trophic levels during the last month.

 

The attached brief video was taken on the weekend, while we were following a school of Long-beaked common dolphin. They are always so full of energy, but this time it was something that we do not often observe often. They were literally “flying” out of the water as they were moving so fast. It was only when Jake Keeton casually mentioned that a male and female killer whale were in pursuit, that we realised what was going on. And the next minute, bang, the female killer whale smashed the poor common dolphin right out of the water.

 

We then observed behavior that we have never witnessed before. The killer whale started skinning the dolphin just below the surface. Blood could be seen in the water as the animal was soon devoured. The male and female killer whales took off as quickly as they arrived on the scene. It was also the first time that Purity Khosa our head guide had observed killer whales. What a treat for someone who hails from Mpumalanga and is still relatively new to our marine world!