Surfer Arlen Macpherson sits on his board, which has an electronic shark repellent device installed, at Sydney's Bondi Beach in Australia, August 18, 2015. A spate of shark attacks in Australia has left some of world's top surfing beaches deserted and many people having second thoughts about taking a swim as the summer approaches. Macpherson paid A$390 for a device embedded in his surf board to repel sharks by emitting an electronic force field that overpowers its sensing organs. (Photo by David Gray/Reuters)

A surfing movie poster, a phone cable and a wood carving adorn the wall of a surfboard workshop owned by Craig 'Buddha' Cummins where he installs shark repellent devices in Sydney, Australia, August 14, 2015. (Photo by David Gray/Reuters)

Surfer Arlen Macpherson sits on his board, which has an electronic shark repellent device installed, at Sydney's Bondi Beach in Australia, August 18, 2015. (Photo by David Gray/Reuters)

Surfer Arlen Macpherson carries his board, which has an electronic shark repellent device installed, along Sydney's Bondi Beach in Australia, August 18, 2015. (Photo by David Gray/Reuters)

Surfer Arlen Macpherson checks the electronic shark repellent device he had installed in his board as he exits the water at Sydney's Bondi Beach in Australia, August 18, 2015. (Photo by David Gray/Reuters)

Surfer Arlen Macpherson sits on his board, which has an electronic shark repellent device installed, at Sydney's Bondi Beach in Australia, August 18, 2015. (Photo by David Gray/Reuters)

Surfboard repairman Craig “Buddha” Cummins holds a shark repellent device as he prepares to install it in a board at his Sydney workshop in Australia, August 14, 2015. (Photo by David Gray/Reuters)

A surfer carries his board as he walks along Sydney's Bondi Beach in Australia, August 18, 2015. (Photo by David Gray/Reuters)

Surfboard repairman Craig “Buddha” Cummins installs a shark repellent device in a board at his Sydney workshop in Australia, August 14, 2015. (Photo by David Gray/Reuters)

Surfboard repairman Will Burgess checks the alignment of a wire as he installs a shark repellent device in a board at his Sydney workshop in Australia, August 14, 2015. (Photo by David Gray/Reuters)

Surfboard repairman Will Burgess checks the alignment of a wire as he installs a shark repellent device in a board at his Sydney workshop in Australia, August 14, 2015. (Photo by David Gray/Reuters)

Surfboard repairman Will Burgess checks the alignment of a wire as he installs a shark repellent device in a board at his Sydney workshop in Australia, August 14, 2015. (Photo by David Gray/Reuters)