Finally seen: a rare sighting of Antarctic blue whale cow–calf pair off the west coast of South Africa

Abstract

Blue whales are rarely sighted off the coasts of South Africa due to their low numbers and offshore habitat preference. Visual observations to search for marine mammals were conducted onboard a platform of opportunity during the Integrated Ecosystems Programme survey in November 2019. A cow–calf pair of blue whales Balaenoptera musculus was sighted offshore Kleinzee (30°05′02.4" S, 14°24′53.2" E) at a water depth of 1670 m on the west coast of South Africa in the southern Benguela Current System. The pair was identified as Antarctic blue whales B. m. intermedia based on the size of the cow (~ 29 m), “torpedo-shaped” body of the cow, known distribution ranges and recent acoustic data showing that pygmy blue whales B. m. brevicauda do not occur in these waters. The calf was likely born in the Benguela ecosystem given its relatively small size. This is the first sighting of Antarctic blue whale cow–calf pair in South African waters post whaling, indicating that animals might still use this area as a calving or nursing ground. Improved protection of this region in the low latitudes might benefit the recovery and conservation of the species.