CAPE TOWN – South Africa’s great white sharks could die out because of human interference, ocean pollution and a limited gene pool, a new study released on Wednesday showed.
There are 350-520 great white sharks left off the South African coast, 50 per cent fewer than previously thought, according to a six-year study carried out mainly in Gansbaai, a shark hotspot 160 kilometers from Cape Town.
“South Africa’s white sharks faced a rapid decline in the last generation and their numbers might already be too low to ensure their survival,” said Sara Andreotti, research leader and marine biologist at the University of Stellenbosch.
Scientists say there are still thousands of great white sharks off the coast of Australia, Canada and the east coast of the US.
Thousands of tourists travel to South Africa’s Western Cape each year to catch a glimpse of the ocean’s top predator from underwater cages, but human interaction has made the largest contribution to declining local shark numbers.
Shark nets used to protect swimmers and surfers killed more than 1000 great whites off the Durban coast in the 30 years up to 2008, while trophy hunting and pollution also killed off large numbers of a species which can trace its lineage back 14 million years.
South African great white sharks also have the lowest genetic diversity of all white shark populations globally, making breeding more problematic and the likelihood of illness higher, the study, which included documenting individual sharks by their dorsal fins, showed.
