Cape Town - Shark researcher Paul von Blerck will pack up his new electronic shark-repellent cable at Glencairn Beach at the end of the month and head back to KwaZulu-Natal – none the wiser if the device works at keeping great whites away from the beach.
“We’ve learnt a tremendous amount about the engineering side, and are confident we can put this up at certain beaches elsewhere, but from the animal side it’s been very disappointing. There have been some sightings of white sharks at Fish Hoek, but in the months I’ve been here I have not seen one at Glencairn. And now the shark season has ended.”
Von Blerck, a researcher at the KwaZulu-Natal Sharks Board in Durban, installed the 100m electronic cable at Glencairn in October and activated it in November. It is fixed to the seabed with vertical “risers” and emits a low-frequency, low-power electronic field.
He had hoped that sharks, which are extremely sensitive, would move away from the area once they had detected the electronic field.
But to see if it worked, he needed great whites to cruise by and there has not been a single one the entire summer.
A video camera was installed on the peak above the beach, which rolls during the daytime to record the behaviour of the great whites.
“We’ve got footage from the beginning of November, which is going to be reduced by a company for us, and we’re hoping the camera will have picked up some shark activity. We’re looking to enhance the images,” Von Blerck said.
The electronic device technology, developed and owned by the Sharks Board, did not harm the sharks.
“Ultimately the Sharks Board is looking at alternatives to shark nets, that’s the long-term goal. Hopefully nets can become a thing of the past.
“I’ve spent 34 years at the Sharks Board and this has been my life’s work and my dream to have something better than shark nets. No one wants to see anything give up its life for humans.
“When I was a child, I remember in 1969 the first man that walked on the moon, yet 45 years since then and we can’t devise something which stops sharks coming inshore.”
Glencairn was selected as the test spot because there was a good understanding of great white movements along the coast, the water was shallow and calm, and there were good vantage spots on Elsies Peak to observe shark behaviour when they encountered the cable.
Shark scientist Alison Kock, research manager for the city council’s Shark Spotters Programme, said yesterday they could not say what had caused changes in the number of sharks in False Bay in different years, but thought it may be related to long-term environmental patterns which were not clear.