Shark barrier trial

Shark barriers create a fixed swimming enclosure, from the shoreline out to sea, and from the water surface to the seabed. Shark barriers have been used successfully in Western Australia to maximise swimmer safety while minimising harm to sharks or other marine life.

Suitable locations for a barrier depend on local conditions:

• South East Queensland beaches are unsuitable for shark barriers due to surf conditions (also known as ‘high energy’ beaches)
• North Queensland beaches are partially protected by the Great Barrier Reef and may be more suitable (referred to as ‘low energy’ beaches).

Criteria for a suitable site

• Tidal ranges less than 3.5m
• Currents less than 1m/s
• Water depths at lowest astronomic tide greater than 1m
• Maximum wave height less than 2m
• No seagrass meadows or fringing reef
• Not adjacent to river mouths (due to flood run-off)

Assessment

A site suitability and risk assessment was undertaken within the Great Barrier Reef Marine Park (GBRMP) that considered the following factors:

• prevailing weather conditions
• risk of extreme weather such as cyclones and floods
• tidal range and currents
• the shape, slope and depth of the beach
• protected marine habitats, such as seagrass meadows and fringing reef
• local beach infrastructure, such as boat ramps, piers and jetties
• existing stinger nets at many beaches
• community support required before installation.

Limitations

The site suitability assessment identified limiting factors, including:

• heavy tropical rains and river flows during the wet season carry large amounts of debris, risking structural failure of the barriers
• large tidal ranges and currents exist in Central Queensland
• some sites contained protected seagrass meadows and fringing reef
• in North Queensland it was found that the community consider marine stingers and crocodiles a greater risk for swimmers than sharks, as shark barriers do not prevent stingers and cannot remove the risk of crocodiles entering the shark barrier
• negative feedback was received on the visual impact of a shark barrier and whether the existence of a barrier could be perceived as an increased risk of shark interactions.

Outcome

Based on this assessment, shark barriers are not considered suitable for Queensland beaches at this time.

We continue to monitor advancements in technology regarding shark barriers, including beach-based electronic barriers, for future consideration.

Contact

Email scp@daf.qld.gov.au