Cape fur seal in the Sardine Run

Cape fur seals (Arctocephalus pusillus pusillus) belong to the eared seal family (Otariidae) and are a sub species of the Afro-Australian Fur seal. Sub species are genetically similar species that are separated geographically (living in different parts of the world) or ecologically (same area, different prey or habitat preferences). In South Africa the Cape fur seal is the only seal species that breeds here, however, other species such as elephant seals, Subantarctic fur seals, leopard seals occasionally occur along our coastline. Locally, Cape fur seals normally reside on offshore islands or isolated beaches along the western and southern coasts of South Africa and Namibia. The most eastern colony occurs at Black Rock Island of Port Elizabeth. The occurrence of Cape fur seals in the annual sardine run is limited. Divers will frequently encounter single fur seals opportunistically feeding on sardines alongside common dolphins and sharks. However, rarely will more than single individuals be encountered.This species is an inquisitive and friendly animal when in the water, and will often accompany scuba divers. They will swim around divers for periods of several minutes at a time, even at a depth of 60m. On land, they are far less relaxed and tend to panic when people come near them. South African fur seals have a very robust and healthy population. Harvesting of seals was outlawed in South Africa in 1990.

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Cape fur seal ecology

The African fur seal lives around the southern and southwestern coast of Africa from Cape Cross in Namibia and around the Cape of Good Hope to Black Rocks near Port Elizabeth in the Eastern Cape province.  Brown fur seals prefer to haul out and breed on rocky islands, rock ledges and reefs, and pebble and boulder beaches. However, some large colonies can be found on sandy beaches. Fur seals spend most of the year at sea, but are never too far from land. They have been recorded 160 km from land, but this is not common.

The African fur seal’s diet is made of up to 70% fish, 20% squid and 2% crab. Also eaten are other crustaceans, cephalopods and sometimes birds. In rare instances they have even been documented attacking and eating sharks. A recent incident occurred off Cape Point, South Africa, where a large male was observed attacking and killing five blue sharks between 1 and 1.4 metres long. Observers concluded that the seal likely killed the sharks to eat the fish rich contents of their stomachs as well as their livers as a source of energy. The Cape fur seal’s main predator is the great white shark, although they are also preyed upon by various other animals, as well, such as orcas. Land-based predators include black-backed jackals and brown hyenas on the Skeleton Coast in Namibia. In South Africa, the seals employ a number of anti-predatory strategies while in shark-infested waters, such as:

• Swimming in large groups and harassing sharks in the vicinity
• Low porpoising to increase subsurface vigilance
• Darting in different directions to cause confusion when attacked
• Using their greater agility to stay out of reach
• Riding near the dorsal fin to keep out of reach of the shark’s jaws when attacked