Orcas have seized the spotlight this year in the “greatest shoal on earth”, the sardine run off the east coast of South Africa from June to July — which has had exceptionally high numbers of sardines and predators this year.
Underwater photographer Steve Benjamin, who has been a sardine run operator on the Wild Coast for the past 16 years, said: “This year has been way above average, bigger than anything I've ever seen in the past. I’ve seen a huge amount of sardines travelling up the coast.
“We are seeing huge numbers of gannets and ocean predators. We have seen many species of sharks, Bryde’s whales, migrating humpbacks and orcas, the predators of predators.”
In the past week Benjamin and conservationist Andy Coetzee, who also runs ocean trips during the sardine run, saw a trio of orcas feeding off a young humpback whale and a pod of orcas hunting dolphins.
The hunting and dietary habits of orcas off South Africa's shores have attracted attention in the past few years, after they started killing iconic white sharks off the Western Cape coast.
“Orcas sporadically show up on the coastline and last week we were lucky enough to see a group of five which had a calf with them. While we were watching they turned and (hunted) a whole school of common dolphins,” Benjamin said.
“They singled out a mom and a youngster and separated them. They kept chasing and diverting the young (dolphin) and teaching their youngster how to hunt and feed,” Coetzee added.
A free diver who launches trips from Hole in the Wall, Coetzee said of another orca sighting: “I saw a big dorsal fin come out of the water and then another dorsal fin, belonging to orcas. The front pectoral fin of a young humpback was floating on the surface but it was already dead. They were circling it with a sub-adult orca, bringing the humpy to the surface (for a moment) to feed.”
Marine mammal biologist M’du Seakamela, of the department of forestry, fisheries and the environment, said: “I know of one case of orca predation on humpback whales off Jacob’s Baai, on the west coast and two off East London and Mbhashe, on the east coast.”
People go crazy for a lion kill in the Kruger. We saw the apex predator in the ocean.
— Conservationist Andy Coetzee
Humpback whale numbers off the west and east coasts have rebounded from low levels post exploitation and the population is increasing at about 8% per annum, he said.
Seakamela is a leading researcher on humpback “supergroups”, the unusual groupings of up to 200 whales at a time off the west coast. The area is a unique feeding ground, away from the traditional feeding grounds in the polar and subpolar regions. He has studied humpback feeding ecology and behaviour, and is part of a South African Orca Project across institutions.
A pair of orcas, nicknamed Port and Starboard, first made headlines for targeting white sharks for their livers, removed with almost surgical precision, according to marine biologist and white shark expert Alison Towner, who conducted the white shark autopsies.
Coetzee spoke about spectacular sightings during this year’s sardine run — an annual event which has been compared to the Serengeti’s wildebeest migration for its scale and intensity — including a humpback whale “lunge feeding”. The whale came up about one foot from where he was free-diving in a surge of bubbles.
“We even saw a baitball of mackerel (not sardines) and all the sharks — black tips, duskies, bronze whalers — on it and 400 to 500 gannets dive bombing into it, and dolphins mauling the (fish) to pieces,” he said.
Of the orca predation, he said: “They can inhabit all the oceans. People go crazy for a lion kill in the Kruger. We saw the apex predator in the ocean.”
