A pair of killer whales, nicknamed ‘Port and Starboard’, has been terrorizing great white sharks. In recent years as many as 8 sharks (possibly more) have succumbed to the pair. Many of the discovered sharks were missing their fatty liver and sometimes their heart. While orca hunting escapades are not particularly newsworthy, the antics of these orcas have attracted the attention of scientists as they are altering the ecosystem. Once word got out in the shark community, great white numbers off the Gansbaai coast of South Africa have declined. Can you really blame them for leaving? Only in horror movies do victims willfully stick around and seek out their attackers.
With the decline in great white sharks, other predators have moved in including bronze whaler sharks, Carcharhinus brachyurus. The heavy reliance of orcas on top predators for food may reflect changes in the availability of other prey in their ecosystem. No doubt these orcas and their impact on the ecosystem will be closely examined.
AV Towner, RGA Watson, AA Kock, Y Papastamatiou, M Sturup, E Gennari. Fear at the top: Killer whale predation drives white shark absence at South Africa’s largest aggregation site. African Journal of Marine Science. 44(2): 139-152, 2022.