Scientists in Cape Town have discovered that only female great white sharks come close to shore in the city’s False Bay.
The ground-breaking research, led by local shark scientist Alison Kock, tracked the movements of 56 tagged sharks of both sexes in False Bay over the last three years.
While researchers have known for some time that the sharks tend to come inshore in False Bay in spring and summer, Kock says that the big question remaining is why only female sharks and not males. The scientists are unsure whether their findings suggest that all previous great white shark attacks on humans in the area were most likely by female sharks.
The report confirmed that the sharks congregate around Seal Island in autumn and winter, where they feed on seals, before leaving the island in spring and summer in pursuit of migratory fish moving inshore.
Kock said that the new research could help in shark management, and warned that had the Cape Town city council gone ahead with its now-abandoned plan of erecting traditional shark nets at beaches, it would have inadvertently killed only the female of the species.
The traditional shark nets are designed to reduce numbers by entangling and killing sharks, but they also have the unintended effect of killing other species including dolphins. There are plans to erect small-meshed nets at Fish Hoek in southern Cape Town, designed just to exclude and not kill the sharks.
Following numerous shark attacks and sightings in 2012 Cape Town increased its shark-spotting programme.