Cape Town tests shark-repellent system

Cable emits frequency known to repel sharks

An experimental electronic system to repel sharks from Cape Town waters will be tested in October to try and prevent future shark attacks.

The 100-m long cable is being tested by the KwaZulu-Natal Sharks Board (KZNSB) at Glencairn beach in Cape Town. The electronic system emits a low-frequency pulsed signal that is known to repel sharks but is safe for bathers. The cable will be installed parallel to the shore and will be activated on certain days, during daylight hours, from November until next March.

If successful it could replace the current programme of shark nets and “drumline” traps deployed in the Cape Town area.

Throughout the testing period the system will be monitored by video cameras from the beach and by shark spotters from higher ground. Their combined records will allow the KZNSB to understand how sharks react to the magnetic field.

Designed in 2012 by Cape Town's Institute for Maritime Technology, the eco-friendly system comprises a main cable fixed to the sea floor, with electrode-emitting vertical "risers" kept upright by buoys.