Whales and Dolphins

The diversity of these large marine mammals in South African waters is remarkable, with over 40 species that depend on our rich coastal and open ocean ecosystems. The waters near Cape Town support the widest diversity, including five species of dolphin and three species of baleen whale, as it is the boundary between the cold Benguela ecosystem and the warmer Agulhas Current. The close continental shelf around Cape Town also means that some deep-water species like pilot whales are occasionally seen.

Cetaceans comprise two basic taxonomic groups, the mysticetes (filter feeding whales with baleen) and the odontocetes (predatory whales and dolphins with teeth). The term ‘whale’ is used to describe cetaceans larger than approximately 4 m in length, in both these groups and is taxonomically meaningless For example, the killer whale and pilot whale are members of the Odontocetes and the family Delphinidae and are thus dolphins, not whales.

WHALES

Large super-pods of humpback whales feed off the coast offshore of Cape Town to Yzerfontein on their annual migration from the tropics to Antarctica. These are the largest groups of humpbacks known on Earth. Cape Canyon MPA protects these important feeding areas.

The seasonal Walker Bay MPA was designed to protect southern right whales that calve in these waters for three months of the year around spring. In a recent survey scientists recorded nearly 1400 whales the bay. De Hoop MPA provides additional protection to southern right whales and Addo Elephant National Park MPA will provide further protection up the coast in Algoa Bay.

Although most of the baleen whales have shown good signs of recovery from commercial whaling in the 20th century, particularly the southern right and humpback whales, others such as the Antarctic blue, fin and sei whales are still listed as Endangered or Critically Endangered on the South African Red list.

DOLPHINS

All the dolphin species are considered resident although many show some seasonal movements along the coast. The common and bottlenose dolphins that frequent the Transkei coast have become world-famous and feature in BBC's latest Blue Planet II. Amathole Offshore MPA provides protection for these two species along this stretch of coast. Namaqua National Park MPA provides protection for the playful Heaviside's dolphins.

Although dolphins were not subject to commercial whaling, their coastal distribution brings them into close contact with human activities such as fishing nets, anti-shark bather protection nets, pollution from rivers, noise and injury from ships and recreational boats etc.

The Indian Ocean humpback dolphin is the only dolphin listed as Endangered in South Africa. There have been clear decreases in sightings and group sizes throughout their range. Humpback dolphins are split into two populations in South Africa, one ranging along the Cape south coast and one on the northern KZN coast – combined there are likely only around 500 individuals of this species in the country, making them one of the rarest mammal species in the country. Find out more by visiting the Sousa Project. uThukela Banks MPA will provide protection for humpback dolphins.

For more information about whale and dolphin research in South Africa visit Sea Search.