Supergroup humback whale sightings on the increase in South Africa

While whales are a common site off South Africa’s coastline from June to November, they can usually be seen in small pods.

But almost 50 years after whaling was banned, an extraordinary spectacle is unfolding. Massive supergroups of humpback whales are becoming increasingly common.

Together with dolphins, they are one of at least 37 species of marine mammals that can be found in South African waters.

Cape Town wildlife photographer, Chris Fallow, has been capturing these breathtaking gatherings up close.

He says that out on his boat towards the end of last year, he noticed that whale numbers were steadily increasing.

"Initially, we saw groups of 20, maybe even 50. But, towards the middle of December, those groups grew to 100, and we knew something really special was in the offing," he recalls.

He says that at the end of the month, about 100 kilometres north of Cape Town, they saw what he can only describe “as a Manhattan skyline with huge plumes of whale breath greeting us like skyscrapers”.

“Very quickly we realised we were looking at a sight we had never seen before in our lives, and that was of hundreds of whales coming together to feed in one small area,” he says.

By photographing each unique whale tail, known as a fluke, and submitting these images to the Happywhale citizen science platform, Fallows realised he’d been among 299 humpback whales.

It marked the largest sighting ever submitted to the platform of the species in one place in a 24-hour period.

Fallows' wife, Monique, who works with him on his photographic shoots, was with him on the boat at the time and describes the experience as “mind blowing”.

"We could hear them. We could smell them. So, the funny thing about humpback whales is that they actually smell really bad,” she says.

“They’re feeding on krill, which are very fishy, and they actually burp and they fart all the time. So, the smell was really overpowering.”

Humpback whales stop off along South Africa’s south coast to feed, calve, and rear their young as they migrate northwards from Antarctica.

The International Whaling Commission says that since the 1986 global hunting ban, numbers have risen from about 10,000 to approximately 100,000 in the Southern Hemisphere.

Dr Els Vermeulen, Chief Scientist in the University of Pretoria’s Whale Unit says the first supergroups was recorded in about 2012.

“It’s very likely a result of the recovery of the population from whaling. Humpback whales were severely hunted to very low numbers,” she says.

“But as these they recover from whaling, and populations rebound, these supergroups are forming again now in our rich, Benguela upwelling system."

Vermeulen says whales congregating in supergroups make vocalisations which attract other whales to the food-rich area.

However, an increase in whale numbers introduces conservation challenges too, most significantly from ship strikes resulting in whale injury and death.

A recent preliminary assessment she co-authored suggests a quadrupling of fast-moving vessels on South Africa’s south-west coast since December 2023, in part due to the Middle East conflict which has diverted ships.

Most whales struck by vessels will sink in the ocean, so statistics are not available, but a few carcasses wash ashore.

Gregg Oelofse, coastal and environmental manager for the City of Cape Town, says there are a lot of tankers, cargo ships, and fishing vessels coming around the coastline.

“We do on occasion find a carcass that comes ashore, and we’ll very clearly see, because we’ll see the propellor strike, often, through the whale’s body," he says.

Vermeulen says when humpback whales are feeding they are not very aware of their environment. She is liaising with the shipping sector to find solutions to ship strikes.

“Because it’s usually closer to shore, what we’re looking at is speed reductions ... especially when we approach the harbours of Saldanha bay and Cape Town,” she says.

Currently, there are no regulations in South Africa to lower shipping speeds to protect whales.