SHARK MITIGATION SCIENCE
Accessible Research, Safer Waters
Spatial deterrent research
This type of mitigation aims to capture, kill, translocate, or intercept sharks before they enter a coastal zone. For example, shark nets (meshing), traditional drumlines or SMART drumlines (Shark Management Alert in Real Time).
Some spatial deterrents aim to capture and relocate sharks (SMART drumlines). Most other spatial deterrents are designed to capture and kill sharks before they can enter the coastal zone (meshing/nets, traditional drumlines). We can assume that reducing shark populations helps us to mitigate shark bites in theory, but in reality, we do not know that this is true. This is important to keep in mind while reading spatial deterrent studies.
The research
This study assesses the effectiveness of shark nets in NSW, Australia. Differences in the rate of shark-human interactions could not be detected at netted versus non-netted beaches. The low rate of shark interactions and high variance limits statistical differentiation. The study suggests that area protection alone is not sufficient to reduce shark-human interactions.
Huveneers, C., Blount, C., Bradshaw, C.J., Butcher, P.A., Smith, M.P.L., Macbeth, W.G., McPhee, D.P., Moltschaniwskyj, N., Peddemors, V.M. and Green, M., 2024. Shifts in the incidence of shark bites and efficacy of beach-focussed mitigation in Australia. Marine pollution bulletin, 198, p.115855.
Vancouver
This study assesses the ability of SMART drumlines to reduce the risk of shark bites. Two white sharks were caught, translocated and predominantly stayed offshore, however, 24 other tagged white sharks were detected within the experimental zone and were not caught by the SMART drumlines.
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Taylor, S.M., How, J., Travers, M.J., Newman, S.J., Mountford, S., Waltrick, D., Dowling, C.E., Denham, A. and Gaughan, D.J., 2022. SMART Drumlines Ineffective in Catching White Sharks in the High Energy Capes Region of Western Australia: Acoustic Detections Confirm That Sharks Are Not Always Amenable to Capture. Biology, 11(10), p.1537.
This study aimed to assess the effectiveness of the Shark Meshing program. Shark bite incidents declined over the experimental period, however, two points warranted attention. 1. factors such as changing ocean use advances in beach patrols and changes in medical response were overlooked and 2. the proportion of fatalities significantly decreased.
Gibbs, L., Fetterplace, L., Rees, M. and Hanich, Q., 2020. Effects and effectiveness of lethal shark hazard management: the Shark Meshing (Bather Protection) Program, NSW, Australia. People and Nature, 2(1), pp.189-203.
Results showed that SMART drumlines do not attract bull sharks. Tagged bull sharks were detected within the experimental area which shows that drumlines did not provide an impenetrable barrier to sharks.
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Guyomard, D., et al. (2020). "SMART drumlines at Reunion Island do not attract bull sharks Carcharhinus leucas into nearshore waters: Evidence from acoustic monitoring." Fisheries Research 225.
This study compared the movements of sharks using drones, SMART drumlines and VR4G tracking technology. Drone observations did not correlate with SMART drumline and VR4G data. SMART drumlines did not stop sharks from entering near the surf zone, and SMART drumline catches didn't coincide with the portion of sharks detected by the VR4G acoustic receivers.
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Colefax, A. P., et al. (2020). "Comparing distributions of white, bull, and tiger sharks near and away from the surf break using three tech-based methods." Ocean & Coastal Management 198: 105366.
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 compares three shark control programs - New South Wales (NSW), Queensland and KwaZulu-Natal (KZN). ​All three programs aim to reduce shark populations. The study concluded that the number of days when nets are deployed in KwaZulu-Natal can be decreased.
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Dudley, S.F., 1997. A comparison of the shark control programs of New South Wales and Queensland (Australia) and KwaZulu-Natal (South Africa). Ocean & coastal management, 34(1), pp.1-27.
The state government of Hawaii implemented a shark control program between 1959 and 1976 where 4,668 tiger sharks were killed. The program did not have a measurable effect on the rate of shark bites in the region.
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Wetherbee, B.M., Lowe, C.G. and Crow, G.L., 1994. A review of shark control in Hawaii with recommendations for future research.
