South African fur seals (also known as the Cape fur seal) of Algoa Bay.
By Purity Khosa

Thursday, 13th February 2025

Did you know Algoa Bay is home to a thriving population of South African fur seals? A population that breeds on Black Rocks, a part of the Bird Island group. These charismatic marine mammals are often seen basking on the islands, bows and rudders of cargo ships, playing in the waves, or darting through the water near our boats when on tour. But while they may seem cute and playful, these seals are also skilled hunters with a surprising impact on the marine ecosystem!

South African fur seals (Arctocephalus pusillus) are the only seal species that breed along the South African and Namibian coasts. They are incredibly adaptable and can be found on rocky islands, beaches, and even man-made structures. Seals are social animals, often seen in large groups, with males aggressively defending their territories from other bulls during the breeding season. Where males have a harem of up to about 50 females per individual.

Sexual dimorphism exists in these seal species. Males can grow up to 2.5 meters long and weigh over 300 kg, with females being slightly smaller, reaching about 1.5 meters and 75 kg. Males also have a large chest and a thick mane, and the smaller females have silver-grey fur. These seals are incredible divers, capable of holding their breath for up to about 7 minutes and reaching depths of 200 meters while hunting for fish and squid.

They are also opportunistic feeders. Their diet mainly consists of fish (like sardines and anchovies), rays and squid, but they have also been observed catching seabirds —including endangered African penguins!

Predation on African Penguins:

While not their primary food source, some South African fur seals have developed a habit of hunting African penguins, particularly around St. Croix Island and Bird Island, the African Penguin colonies of Algoa Bay. This behavior is of growing concern as African penguin populations are already under a bigger threat due to habitat destruction, overfishing, climate change and oil spills from ship-to-ship bunkering. From our observation, during the times when bunkering was not in operation, penguin numbers seemed to have increased. But only the conservation experts can confirm this.

Rabies Concern in South African fur seals is an important Wildlife Health Alert:

Some South African fur seals have tested positive for rabies. Rabies is a viral disease that affects the nervous system of mammals and this includes humans. Rabies-infected seals may display strange behavior, such as aggression, confusion, excessive drooling and uncoordinated movements. This virus can be transmitted through bites and scratches. People must therefore avoid direct contact with seals, even if they appear injured or in distress. If you spot a sick or stranded seal, do not approach it, instead, report it to local marine conservation authorities (Bayworld) for proper handling.

According to Dr. Greg Hofmeyr, not a lot is known about rabies in seals. But a few scientists have started studying it in the past few months. Currently, 44+ cases have been reported and 44% of the carcasses sampled tested positive. Euthanasia on rabid seals might be done going forward. It is suspected that the initial infection originated from jackals in Namibia or on the Northern Cape coast. There are no confirmed cases in the Eastern Cape yet. But there is a potential. Dr Greg Hofmeyr spotted one aggressive seal in Jeffrey's Bay.

Guidelines for the public

Please always keep your distance from seals (in the water and on

the land).

It is illegal to disturb or injure a seal in any way. Do not attempt

to chase, touch, or restrain.

Ensure that your dog is on a leash and under your control at all

times wherever seals may occur.

Do not touch, handle, or consume a seal carcass or any parts

thereof.

Listen and obey requests to vacate the sea or coastal areas as

given by City officials, City lifesaving staff, SANParks staff, or their

representatives.

If you are bitten by a seal, wash the wound out ASAP with soap

and water for 5-10 minutes and seek medical attention

immediately.

Report any seals ashore or incidents immediately to the Bayworld

Stranding Hotline: 071 724 2122.

Want to see South African fur seals in action? Join us on a Penguin, Whale & Dolphin Island Cruise to observe these fascinating creatures in their natural habitat!