- Title: South Africa's Great White shark population declining rapidly, says study
- Date: 26th September 2016
- Summary: VARIOUS VISUALS OF SHARK DORSAL FINS
- Embargoed: 11th October 2016 13:06
- Keywords: great white sharks extinction South Africa pollution
- Location: CAPE TOWN, GAANSBAAI AND STELLENBOSCH, SOUTH AFRICA
- City: CAPE TOWN, GAANSBAAI AND STELLENBOSCH, SOUTH AFRICA
- Country: South Africa
- Topics: Environment,Nature/Wildlife
- Reuters ID: LVA004517CSW7
- Aspect Ratio: 16:9
- Story Text: South Africa's great white sharks could die out due to human interference, ocean pollution and a limited gene pool, a new study shows.
There are between 350-520 great white sharks left off the South African coast, 50 percent fewer than previously thought, according to a six-year study, carried out mainly in Gansbaai, a shark hotspot 160 kilometres from Cape Town.
Sara Andreotti, research leader and marine biologist at the University of Stellenbosch, says the country's white sharks have been facing a rapid decline in the last generation and their current numbers could already be too low to prevent their disappearance from South Africa's coastal waters.
"Great white sharks are a very iconic species of sharks and despite South Africa - it was the very first country to protect them - they have been targeted for many years before as dangerous species for humans. So these causes of decline can also be historical situation where the animals have been killed for so long and so intensively, that the population never recovered," she said.
Scientists say there are still thousands of great white sharks off the coast of Australia, Canada and the east coast of the United States.
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.
"As the cause of the low number of sharks that we found in our study, could have been that these animals are apex predator, which means that they get affected more than other species by pollution and overfishing of the food resources and poaching. So there are several causes that could have been behind this low population," Andreotti said.
Shark nets used to protect swimmers and surfers killed more than 1,000 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.
There are only 333 great whites capable of breeding in South African waters, below the 500 usually needed to prevent "inbreeding depression", the study found.
South Africa helped pioneer great white shark conservation and in 1991 became the first in the world to declare the predator a protected species, with other countries including the U.S. and Australia following suit.
- Copyright Holder: REUTERS
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