SHARK MITIGATION SCIENCE
Accessible Research, Safer Waters
Barrier & enclosure research
This type of mitigation creates a barrier or enclosure so that humans can swim safely in a specified zone. Barriers differ from spatial deterrents such as nets as they do not aim to capture sharks, but to provide an exclusion zone where sharks cannot enter.
Ocean pools are created by walls or nets. Magnetic and electric barriers have also been developed and tested on several different shark species. Read more below.
The research
This study assesses the ability of an exclusion net to keep white sharks out of a swimming area. Thirty-nine white sharks were spotted during the monitoring period. This showed that the net deployment coincided with white shark presence. The report supports the continuation of net use.
Davison, A. and Kock, A., 2014. Fish Hoek exclusion net evaluation report. Shark Spotter Rep.
This study assesses the gear type used for nets and drumlines. Hammerhead sharks and rays were most vulnerable to net capture. More tiger sharks were caught on drumlines. Nets caught more marine mammals, fish and rays, and drumlines caught more loggerhead turtles. Survival rates were lower in nets than drumlines.
Sumpton, W.D., Taylor, S.M., Gribble, N.A., McPherson, G. and Ham, T., 2011. Gear selectivity of large-mesh nets and drumlines used to catch sharks in the Queensland Shark Control Program. African Journal of Marine Science, 33(1), pp.37-43.
This study aimed to determine if the eco-friendly (electromagnetically treated) Exclusion barrier could deter bull sharks deterrent compared to the Sharksafe barrier. Baits that were electromagnetically treated significantly reduced bull shark feeding frequencies and increased avoidance behaviours. The Exclusion barrier did not exclude all bull sharks, but performed better than the Sharksafe barrier.
O’Connell, C.P., Crews, J., King, A. and Gressle, J., 2022. Evaluating the Shark Deterrent Effects of the Novel Exclusion Barrier in Comparison to the Rigorously Tested Sharksafe Barrier Technology. Journal of Marine Science and Engineering, 10(5), p.634.
This study assesses the ability of the magnetic Sharksafe Barrier to deter white sharks. After two years, 34 trials and 255 hours of video footage, all white sharks were excluded from the baited barrier zone.
O'Connell, C.P., Andreotti, S., Rutzen, M., Meӱer, M. and Matthee, C.A., 2018. Testing the exclusion capabilities and durability of the Sharksafe Barrier to determine its viability as an eco‐friendly alternative to current shark culling methodologies. Aquatic Conservation: Marine and Freshwater Ecosystems, 28(1), pp.252-258.
This study assesses the ability the magnetic Sharksafe Barrier to deter bull sharks. Bull sharks did not enter the magnetic region of the experiment, and avoidance and pass around frequencies significantly increased.
O’Connell, C.P., Hyun, S.Y., Rillahan, C.B. and He, P., 2014. Bull shark (Carcharhinus leucas) exclusion properties of the sharksafe barrier and behavioral validation using the ARIS technology. Global ecology and conservation, 2, pp.300-314.
This study assesses the ability of C8 barium-ferrite (BaFe12O19) permanent magnets to deter bull sharks. The magnets significantly reduced feeding events and increased avoidance behaviours. The magnetic barrier reduced entrance frequencies.
O'Connell, C.P., Hyun, S.Y., Gruber, S.H., O'Connell, T.J., Johnson, G., Grudecki, K. and He, P., 2014. The use of permanent magnets to reduce elasmobranch encounter with a simulated beach net. 1. The bull shark (Carcharhinus leucas). Ocean & coastal management, 97, pp.12-19.
This study assesses the ability of permanent magnets to deter white sharks. The magnets were significantly associated with feeding events and increased avoidance behaviours. Results suggest that a physical barrier may be sufficient to deter white sharks, but a magnet may provide additional protection.
O'Connell, C.P., Andreotti, S., Rutzen, M., Meӱer, M. and He, P., 2014. The use of permanent magnets to reduce elasmobranch encounter with a simulated beach net. 2. The great white shark (Carcharodon carcharias). Ocean & Coastal Management, 97, pp.20-28.
This study assesses the ability of the magnetic Sharksafe Barrier to deter white sharks. After two years, 34 trials and 255 hours of video footage, all white sharks were excluded from the baited barrier zone.
O'Connell, C.P., Andreotti, S., Rutzen, M., Meӱer, M. and Matthee, C.A., 2018. Testing the exclusion capabilities and durability of the Sharksafe Barrier to determine its viability as an eco‐friendly alternative to current shark culling methodologies. Aquatic Conservation: Marine and Freshwater Ecosystems, 28(1), pp.252-258.
This study assesses the ability the barium-ferrite (BaFe12O19) permanent magnets on great hammerhead sharks. During the bait experiment, feeding frequency significantly reduced, and avoidance behaviours significantly increased. For the barrier experiment, feeding signficantly reduced and pass-around frequencies significantly increased.
Connell, C.P., Hyun, S.Y., Gruber, S.H. and He, P., 2015. Effects of barium-ferrite permanent magnets on great hammerhead shark Sphyrna mokarran behavior and implications for future conservation technologies. Endangered Species Research, 26(3), pp.243-256.
This study assesses the ability of permanent magnets to deter juvenile lemon sharks from swimming through a magnetic region of a net. In the first trial, all sharks preferred to swim through the control region of the net (no magnets present). The magnets did not affect sharks after 24 hours.
O’Connell, C.P., Abel, D.C., Gruber, S.H., Stroud, E.M. and Rice, P.H., 2011. Response of juvenile lemon sharks, Negaprion brevirostris, to a magnetic barrier simulating a beach net. Ocean &
This study assesses the ability of permanent magnets to deter white sharks. The magnets were significantly associated with feeding events and increased avoidance behaviours. Results suggest that a physical barrier may be sufficient to deter white sharks, but a magnet may provide additional protection.
O'Connell, C.P., Andreotti, S., Rutzen, M., Meӱer, M. and He, P., 2014. The use of permanent magnets to reduce elasmobranch encounter with a simulated beach net. 2. The great white shark (Carcharodon carcharias). Ocean & Coastal Management, 97, pp.20-28.
This study uses bait and barrier experiments to assess if barium-ferrite (BaFe12O19) permanent magnets might influence teleost (fish) and elasmobranch (shark and ray) behaviour. Fish did not have any behaviour changes in relation to the magnets. Shark and ray behaviour significantly changed during the bait experiments, and varied during the barrier experiments.
O'Connell, C.P. and He, P., 2014. A large scale field analysis examining the effect of magnetically-treated baits and barriers on teleost and elasmobranch behavior. Ocean & coastal management, 96, pp.130-137.
This study assesses the effects of the Sharksafe barrier on white shark behaviour. The barrier is made of two elements: (1) visual-artificial-kelp and (2) electrosensory-magnets. The barrier reduced the entrance frequency and increased avoidance and pass-around frequencies.
O’Connell, C.P., Andreotti, S., Rutzen, M., Meÿer, M., Matthee, C.A. and He, P., 2014. Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies. Journal of Experimental Marine Biology and Ecology, 460, pp.37-46.
A 250 m barrier in 3 m of water was installed in St Lucia. The barrier emitted an electric field. When the electric field was off, 28 sharks were caught in the net. When the field was on, zero sharks were caught in the net.
Smith, E.D., 1974. Electro-physiology of the electrical shark-repellant. Transactions of the South African Institute of Electrical Engineers, 65(8), pp.166-181.
This study assesses the ability of the Boat01 to deter white sharks from an extended range (e.g., 6+ meters). The device deterred white sharks, but at close range (approx 2-3 meters).
Riley, M., Bradshaw, C.J. and Huveneers, C., 2022. Long-range electric deterrents not as effective as personal deterrents for reducing risk of shark bite. ICES Journal of Marine Science, 79(10), pp.2656-2666.
This study assesses the ability of underwater sound to deter eight shark species (seven reef and coastal shark species and the white shark). The sounds used were an orca call sequence and an artificially generated sound. When sounds were playing, there were fewer reef and coastal sharks, and sharks displayed fewer interactions with the bait, and displayed less ‘inquisitive’ behaviour, compared to during silent control trials. White sharks spent less time around the bait when artificial sound was playing, but showed no difference in behaviour during orca calls.
Chapuis, L., Collin, S.P., Yopak, K.E., McCauley, R.D., Kempster, R.M., Ryan, L.A., Schmidt, C., Kerr, C.C., Gennari, E., Egeberg, C.A. and Hart, N.S., 2019. The effect of underwater sounds on shark behaviour. Scientific reports, 9(1), pp.1-11.
This study assesses the effects of an intense strobe light and a loud, artificial sound on port jackson, epaulette and white sharks. Light and light & sound decreased the number of baits taken by port jackson and epaulette sharks. Lights did not effect white sharks, but white sharks spent less time around the bait when light & sound were presented together.
Ryan, L.A., Chapuis, L., Hemmi, J.M., Collin, S.P., McCauley, R.D., Yopak, K.E., Gennari, E., Huveneers, C., Kempster, R.M., Kerr, C.C. and Schmidt, C., 2018. Effects of auditory and visual stimuli on shark feeding behaviour: the disco effect. Marine biology, 165, pp.1-16.