Shark barrier

A shark barrier (otherwise known as a "shark-proof enclosure" or "beach enclosure") is seabed-to-surface protective barrier that is placed around a beach to protect people from shark attacks. Often confused with shark nets, shark barriers form a fully enclosed swimming area that prevents sharks from entering (nets aim to reduce shark populations). Shark barrier design has evolved from rudimentary fencing materials to netted structures held in place with buoys and anchors. Recent designs have used plastics to increase strength, versatility and to reduce the environmental damage of bycatch.

Shark barriers are commonly mistaken for shark nets. While they have the same objective of protecting swimmers, they have different characteristics as follows:

Shark barriers work on the principle of excluding sharks from a designated swimming area. Shark barriers form an "underwater fence" from seabed-to-surface, beach-to-beach. Shark barriers are seen as a more environmentally friendly option as they largely avoid bycatch, however they cannot protect the same sized area as culling methods.

Shark (meshing) nets operate as a catch-and-kill strategy to reduce the incidence rate of shark attack by reducing the local population size of sharks. Shark nets have been heavily criticized in the media for the environmental effects of bycatch. They also don't provide a fully enclosed swimming area as sharks can swim above, below or around them.

Shark barriers are not generally used on surf beaches because they usually disintegrate in the swell and so are normally constructed only around sheltered areas such as harbour beaches. It should be noted that where there are surf conditions at Hong Kong beaches, the swell is "typically small". Even if they were in place at surf beaches, they would not protect surfers who go some distance from shore.

The shark nets are more suitable for surf beaches as they can be anchored beyond the deepest sandbank and can be easily taken out of the water when ever any big swell is forecast.

Shark barriers are currently used in Queensland, New South Wales, South Australia and Western Australia. Many of the shark barriers used in Queensland also feature protection from poisonous jellyfish.

Shark barriers are often made out of netting; held in place by a system of piles, anchors and buoys. Netted barriers are susceptible to damage from strong ocean forces and so are generally limited to sheltered bays and beaches and favourable seasons and weather conditions.

Following the controversial Western Australian Shark Cull, the Western Australian State Government trialled a netted shark barrier in Dunsborough in 2013/14 and allocated funds for a new shark barrier to be installed in Busselton. Environmentally friendly shark barriers have also been developed in Western Australia in response to a string of fatal shark attacks on the WA coastline.

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Wikipedia