Southern Right Whales are back- an all time record count in the 2023 aerial survey

Between 27 September and 3 October 2023, the UP Mammal Research Institute Whale Unit conducted the 44th annual aerial survey to monitor the South African population of southern right whales. A total of 38hs 12min of flying time was needed to complete the survey, spread over 6 days.

During this effort, 568 calving females (i.e., with an associated calf; 1,136 whales) were counted and photographed, as well as 40 adult whales without a calf (so-called ‘unaccompanied adults’), bringing the total to the all-time record of 1,176 southern right whales between Nature’s Valley and Muizenberg.

Over 90% of these whales were spread out over the coastline between Blombosstrand (start of St Sebastian Bay) and Hermanus New Harbour. This number of calving females (see figure, blue line) is the all-time record ever recorded on the South African coastline since the start of the monitoring program in 1969, more than the bumper year of 2018 during which we counted 537 females with an associated calf.

As in the past decade, the number of ‘unaccompanied adults’ (UA; males and non-calving females) (see figure below red line) continues to remain extremely low, indicating that they are still not migrating to the South African coast at the same rate as they used to.

Considering the cyclicity seen in the sightings, it can be expected that the number of whales sighted along our coast next year will be considerably lower.

Over 25,000 photographs were taken during the survey for photo identification purposes. These images are currently being sorted and organized so that they can be analyzed for the identification of individual whales, which will take them up to 2 to 3 months.