The Fish Hoek shark exclusion barrier is 350m long
The barrier is located in the southern corner of Fish Hoek bay, an area chosen as it is the most popular bathing area on the beach, and is also mostly sheltered from the prevailing winds and ocean currents in the area. The net is made from flexible HDPE twine and has a depth of between 1 m and 6 m, tapered to the contour of the sea floor. A line of floats along the top and leaded ropes along the bottom ensure that the net forms a complete barrier from sea floor to sea surface, allowing for changes in height of the water column caused by changing tides and waves.
The net is deployed and retrieved daily by hand by a crew of 10 people with the assistance of a small motorised boat. The deployment and retrieval takes approximately an hour each, and overnight the net is stored safely on the beach awaiting deployment the following day.
The design of the Fish Hoek shark exclusion net is completely different to those used elsewhere in the world, in order to allow it to be deployed and retrieved daily. There are two reasons for this:
MINIMISE ENVIRONMENTAL IMPACTS
Entanglement risk for marine animals (particularly cetaceans) is high overnight as it is difficult for animals to see the barrier and the exclusion net is not being monitored. During the day, spotters keep surveillance over the barrier and if any whales or dolphins approach the net a standby team is launched to actively deter them from the area, in line with South African Whale Disentanglement Network protocols.
AVOID DAMAGE FROM ADVERSE WEATHER CONDITIONS
The net is simply not deployed during strong wind and swell conditions (or is retrieved early if weather changes during the day), meaning that you avoid the costly damage to the barrier experienced by other shark exclusion nets during bad weather / storm conditions. Repairs to the net are very simple and can be done on a continual basis on land when the net is not being deployed.