Mist and magic — rare marine pod of Risso’s dolphins spotted in False Bay

It was the boat tour that almost never left Simon’s Town, South Africa’s naval base perched on the edge of the Cape Peninsula.

When dense fog greeted the team at the Simon’s Town Boat Company on the morning of 13 July, owner and skipper Dave Hurwitz faced a difficult call: cancel the scheduled tour or hope that conditions would improve.

“We woke up to a foggy morning,” the company wrote in a Facebook post on the same day. “It was a tough decision whether to green-light or cancel our tour.”

Speaking to Daily Maverick, Hurwitz said they decided to proceed after seeing signs that the fog was lifting. Guests were told they would only be charged if conditions thwarted marine sightings.

The practised skipper and his boat guide’s gamble paid off.

The misty start before everything changed

“I decided to launch in thick fog and then it just revealed itself – first, we saw about 2,000 or more common dolphins, Bryde’s whale, penguins and seals,” said Nanette Smith, the guide on board.

The biggest surprise of the day revealed itself as the boat returned to Simon’s Town shortly after 1pm.

It was a magical encounter, said Smith, and it emerged in the form of a pod of Risso’s dolphins – one of the largest species in the dolphin family.

‘As far as I’m aware, that’s the only record of them’

Hurwitz told Daily Maverick that the species was seldom recorded in South African coastal waters and was typically associated with deeper offshore regions.

“They forage mainly off the continental shelf,” the company wrote after the sighting.

The skipper estimated there were 30 animals in the pod that was observed earlier this week.

He said the company had also witnessed Risso’s dolphins off Hout Bay on the other side of the Cape Peninsula last year. That pod, he estimated, numbered 12 animals, which were also spotted by other observers along that coast.

“I’ve chatted to Professor Ken Findlay and he actually referred to it in his dissertation several decades ago — an anomalous sighting in False Bay,” Hurwitz recalled of a conversation with the South African marine mammal specialist. “As far as I’m aware, that’s the only record of them ever being seen inside False Bay.”

When the emotion sank in

For Smith, the tour guide, the encounter was unlike anything she had experienced. Although she had previously spent eight years whale watching from shore, she said she had never expected to see Risso’s dolphins in False Bay.

“It left me in tears,” she confessed. “To see the guests’ response on the boat, them realising how unique this was ... the whole experience was just mindblowing. It was heartwarming to see other people with tears in their eyes, to even hear Dave just about speechless.”

Unlike some offshore species that enter coastal waters when ill and are later involved in mass strandings, Hurwitz said there was no indication that this pod was in distress.

“These animals were clearly feeding in the bay,” he said.

Other eyewitness accounts later in the day, according to Hurwitz, said the dolphins were heading towards deeper water. He expected they would continue offshore.

The dolphins’ behaviour also suggested they were feeding rather than migrating through the bay in a defined, purposeful direction, argued Smith.

“When animals feed, they move fairly slowly,” she said. In the case of this Risso’s pod, “they spread out in a line, moved for a couple of metres and went below the surface. Then they came back up and grouped together. It was literally as if it was cooperative hunting.”

Though that may be the case, the Dyer Island Conservation Trust reported an uncommon stranding of an adult male Risso’s dolphin further east on the Overberg coast near Hermanus just days before on 5 July.

The “exact cause” of the stranding after a full necropsy remained unknown.

“Risso’s dolphins are known to face a range of human-induced threats, including the accumulation of environmental contaminants in their blubber, which can impair immune and reproductive function, as well as exposure to intense underwater noise, which has been associated with stranding events in this species,” the Trust said.

The ‘mystery’ of Risso’s dolphins

Risso’s dolphins are among the largest dolphin species, growing to about 3.5m in length.

They may occur worldwide but are mainly associated with pelagic waters.

They are also instantly recognisable by the extensive scarring that covers their bodies.

The reason for the distinctive markings was uncertain, Hurwitz’s company argued.

“Their scarring is a mystery,” it wrote. “It’s unclear whether it’s a combination of a lack of repigmentation combined with a slow healing process, or a display of battle scars by ‘macho’ males to impress the females.”

The scars have also been attributed to behaviours such as social interactions.

“No human can script a day like yesterday,” an overjoyed Smith said. “Only Mother Nature can deliver on that.” DM