South Africa is renowned for having one of the world’s biggest populations of great white sharks (Carcharodon carcharias). Substantial declines have been observed, however, in places where the sharks normally gather on the coast of the Western Cape province. Sharks congregate at these locations to feed, interact socially, or rest.
South Africa is renowned for having one of the world’s biggest populations of great white sharks (Carcharodon carcharias). Substantial declines have been observed, however, in places where the sharks normally gather on the coast of the Western Cape province. Sharks congregate at these locations to feed, interact socially, or rest.
In Cape Town, skilled «shark spotters» documented a peak of over 300 great white shark sightings across eight beaches in 2011, but have recorded no sightings since 2019. These declines have sparked concerns about the overall conservation status of the species.
Conserving great white sharks is vital because they have a pivotal role in marine ecosystems. As top predators, they help maintain the health and balance of marine food webs. Their presence influences the behavior of other marine animals, affecting the entire ecosystem’s structure and stability.
Marine biologists like us needed to know whether the decline in shark numbers in the Western Cape indicated changes in the whole South African population or whether the sharks had moved to a different location.
To investigate this problem, we undertook an extensive study using data collected by scientists, tour operators and shore anglers. We examined the trends over time in abundance and shifts in distribution across the sharks’ South African range.
Our investigation revealed significant differences in the abundance at primary gathering sites. There were declines at some locations; others showed increases or stability. Overall, there appears to be a stable trend. This suggests that white shark numbers have remained constant since they were given protection in 1991.
Looking at the potential change in the distribution of sharks between locations, we discovered a shift in human-shark interactions from the Western Cape to the Eastern Cape.
