Between the 1st and 5th of October 2022, the University of Pretoria’s Mammal Research Institute Whale Unit conducted the 43rd annual aerial survey to monitor the South African population of southern right whales. This survey was flown from Nature’s Valley to Muizenberg, using an AS350 (Squirrel) under charter from Silvercoss Helicopters. During the survey, all cetaceans were recorded with a special focus on southern right whales. Photographs were taken of all southern right whale females with associated calves, as well as of all individuals with a brindle, grey or white blaze colouration.

Just less than 21 hours of flying time were needed to complete the survey, spread over a 4-day period. During that time, 304 calving females (i.e. with an associated calf; 608 whales) were counted and photographed, as well as 50 adult whales without a calf (so-called ‘unaccompanied adults’), bringing the total to 658 southern right whales between Nature’s Valley and Muizenberg. As can be seen in Figure 1 below, the vast majority of right whales were observed between De Hoop Nature Reserve and Hermanus New Harbour as is usually the case. Besides southern right whales, we observed 4 humpback whales, several groups of humpback dolphins and bottlenose dolphins, as well as 32 large sharks.

This number of calving females (Figure 2; blue line) is slightly higher than the number recorded in 2015 (249 calving females), but is still well below what we would expect under ‘normal conditions’. These data tell us that females are still calving at lengthier and non-regular calving intervals, which we will corroborate with the photo-identification data.

As in the past decade, the number of ‘unaccompanied adults’ (UA; males and non-calving females) (Figure 2; 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.

A total of 15,116 photographs were taken during the survey for photo-identification purposes. These images are currently being sorted and organised so that they can be analysed for identification of individual whales. Such photo-identification analyses is done with a computer-assisted image recognition system, followed by final confirmation and matching of the whales by eye, and usually takes about 2 months to complete. Through such analyses, we will be able to determine which females calved this year, how long it took them to produce a new calf, their individual distribution and movement patterns and, with considerable accuracy, assess their overall reproductive success. These aspects are vital to monitor the recovery of the South African population of right whales, which has been increasing at a rate of 6.5% per year since international protection of the population against whaling. These analyses will also allow us to investigate further possible causes and consequences of the concerning decrease in sightings along our shores in recent years.

The MRI Whale Unit wishes to thank all those who continue to support the survey, such as Silvercross Helicopters, De Hoop Collection, Grootbos, Orms, Canon South Africa, Denel Overberg Test Range and private citizens along the route. The survey was carried out under a permit from the Department of Forestry, Fisheries and the Environment to approach whales, and under specific Marine Protected Area permits from the relevant conservation authorities. This year’s survey was funded by TotalEnergies to whom we are thankful for their continued support.

Should you wish to support this very important research and conservation programme, and stay up-to-date on the status of our southern right whale research, please contact us to find out more about our exciting and informative adoption programme run in collaboration with WWF South Africa. Symbolic whale adoptions make unique and exciting gifts, and are an authentic opportunity for corporate environmental responsibility. All funds raised in this way directly support our fieldwork.

https://donate.wwf.org.za/adoption/adopt-a-whale

Tune in on our work via our social media, as we will continue to post very regular updates of our research:

• https://www.facebook.com/MRIWhaleUnit

• https://www.instagram.com/mriwhaleunit/

• https://www.linkedin.com/company/mammal-research-institute-whale-unit

• Twitter: @MRI_Whale_Unit

For further enquiries please contact Dr Els Vermeulen (Research Manager) at els.vermeulen@up.ac.za / 060 9714301 or Chris Wilkinson (Technical Manager) at 083 580 8247.