The Mammal Research Institute Whale Unit of the University of Pretoria studies whales, dolphins and porpoises (cetaceans) in southern African waters. Its primary objective is to provide information that promotes their protection and conservation.
Our work includes researching the ecology, population dynamics and behaviour of these marine mammals to better understand their conservation status and needs.
Building on pioneering research initiated by the late Professor Peter B. Best in the 1960s, the Whale Unit has continued to monitor southern right whales since 1969. Using annual surveys, including photo-identification photography, the research is one of the longest continuous datasets for any marine mammal in the world. As such, it is an extremely valuable dataset that is of national and international importance.
The Whale Unit is recognised as an international thought-leader in knowledge, research and conservation of cetacean fauna in southern African waters and the surrounding oceans.
Monitoring the South African population of southern right whales
We have been monitoring the southern right whale population along the South African coast since 1969, and using photo-identification since 1979. This research is done annually in October through photo-identification aerial surveys. It involves counting and photographing all female southern rights with calves between Nature’s Valley and Muizenberg.
Using the photographs, we are able to identify individual females based on their unique callosity pattern. This allows us to track them over time and document the main population parameters, such as age of first calving, calving interval (how often the same female has a calf), calf survival rates, number of calving females, total population size and population trends.
This 40+ years of standardised surveys is one of the longest continuous data sets for any marine mammal in the world, making it extremely valuable both nationally and internationally.
Based on survey data, the South African population of southern right whales is estimated at 6,116 and it is increasing by 6.5% per year.
Southern right whales as indicator species
Due to the annual migration of southern right whales from their feeding grounds in the Antarctic to their mating and calving grounds in the coastal waters of South Africa, their health and population dynamics provide important information on changes in the Southern Ocean.
By understanding the essential link between nutritional status and reproduction, the breeding success of the southern right whales provides a measure of changing feeding trends across a wide region of the sub Antarctic and Antarctic Southern Ocean.
The unique long-term database on South African southern right whale population dynamics provides an exceptional opportunity to investigate the effects of environmental variability, including climate change, on the ecology of the Southern Ocean and beyond.
Furthermore, information on the South African population of right whales forms a critical component of the knowledge base for the global population.
We investigate long-term links between the apparent decreased reproductive success of southern right whales along the South African coast line and indices of oceanographic variability in their feeding areas. This information is used to assess whether these in turn coincide with measures of body condition and nutritional stress in pregnant females. Ultimately, this study anticipates to predict the effects of climate change on the population recovery of this depleted krill-dependent species.
In order to achieve this, boat-based fieldwork is carried out during which we obtain skin and blubber samples for isotopic and endocrinologic research. At the same time, drones are used to obtain overhead photographs of the full body length of individual right whales which allows us to quantify their body (and thus nutritional) condition.