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Huveneers C, Blount C, Bradshaw CJA, Butcher PA, Lincoln Smith MP, Macbeth WG, McPhee DP, Moltschaniwskyj N, Peddemors VM, Green M. Shifts in the incidence of shark bites and efficacy of beach-focussed mitigation in Australia. MARINE POLLUTION BULLETIN 2024; 198:115855. [PMID: 38043202 DOI: 10.1016/j.marpolbul.2023.115855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023]
Abstract
Shark-human interactions are some of the most pervasive human-wildlife conflicts, and their frequencies are increasing globally. New South Wales (Australia) was the first to implement a broad-scale program of shark-bite mitigation in 1937 using shark nets, which expanded in the late 2010s to include non-lethal measures. Using 196 unprovoked shark-human interactions recorded in New South Wales since 1900, we show that bites shifted from being predominantly on swimmers to 79 % on surfers by the 1980s and increased 2-4-fold. We could not detect differences in the interaction rate at netted versus non-netted beaches since the 2000s, partly because of low incidence and high variance. Although shark-human interactions continued to occur at beaches with tagged-shark listening stations, there were no interactions while SMART drumlines and/or drones were deployed. Our effect-size analyses show that a small increase in the difference between mitigated and non-mitigated beaches could indicate reductions in shark-human interactions. Area-based protection alone is insufficient to reduce shark-human interactions, so we propose a new, globally transferable approach to minimise risk of shark bite more effectively.
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Affiliation(s)
- Charlie Huveneers
- Southern Shark Ecology Group, College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia.
| | - Craig Blount
- Stantec Australia Pty Ltd., St Leonards, New South Wales 1590, Australia
| | - Corey J A Bradshaw
- Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia
| | - Paul A Butcher
- New South Wales Department of Primary Industries Fisheries, National Marine Science Centre, Coffs Harbour, New South Wales 2450, Australia; Southern Cross University, National Marine Science Centre, Coffs Harbour, New South Wales 2450, Australia
| | - Marcus P Lincoln Smith
- Stantec Australia Pty Ltd., St Leonards, New South Wales 1590, Australia; Faculty of Science and Engineering, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - William G Macbeth
- Stantec Australia Pty Ltd., St Leonards, New South Wales 1590, Australia
| | - Daryl P McPhee
- Faculty of Society and Design, Bond University, Gold Coast, Queensland 4229, Australia
| | - Natalie Moltschaniwskyj
- New South Wales Department of Primary Industries Fisheries, Port Stephens Fisheries Institute, Nelson Bay, New South Wales 2315, Australia; School of Environmental Science, University of Newcastle, Newcastle, New South Wales 2308, Australia
| | - Victor M Peddemors
- New South Wales Department of Primary Industries Fisheries, Sydney Institute of Marine Science, Mosman, New South Wales 2088, Australia
| | - Marcel Green
- New South Wales Department of Primary Industries Fisheries, Sydney Institute of Marine Science, Mosman, New South Wales 2088, Australia
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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 2022; 11:biology11101537. [PMID: 36290440 PMCID: PMC9598327 DOI: 10.3390/biology11101537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022]
Abstract
The management of human-shark interactions can benefit from the implementation of effective shark hazard mitigation measures. A Shark-Management-Alert-in-Real-Time (SMART) drumline trial in the Capes region of Western Australia was instigated after several serious incidents involving surfers and white sharks (Carcharodon carcharias). The project aimed to determine whether white sharks (target species), which were relocated after capture, remained offshore using satellite and acoustic tagging. Over a 27-month period, 352 fish were caught, 55% of which comprised tiger sharks (Galeocerdo cuvier). Ninety-one percent of animals were released alive in good condition. Only two white sharks were caught; both were relocated ≥ 1 km offshore before release and moved immediately further offshore after capture, remaining predominately in offshore waters for the duration of their 54-day and 186-day tag deployments. Our results confirm that desirable animal welfare outcomes can be achieved using SMART drumlines when response times are minimised. The low target catches and the detection of 24 other tagged white sharks within the study area supported the decision to cease the trial. Our results reiterate there is no simple remedy for dealing with the complexities of shark hazards and reinforce the importance of trialing mitigation measures under local conditions.
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Riley M, Meagher P, Huveneers C, Leto J, Peddemors VM, Slip D, West J, Bradshaw CJA. The Australian Shark-Incident Database for quantifying temporal and spatial patterns of shark-human conflict. Sci Data 2022; 9:378. [PMID: 35794151 PMCID: PMC9259633 DOI: 10.1038/s41597-022-01453-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/06/2022] [Indexed: 01/22/2023] Open
Abstract
We describe the Australian Shark-Incident Database, formerly known as the Australian Shark-Attack File, which contains comprehensive reports of 1,196 shark bites that have occurred in Australia over 231 years (1791-2022). Data were collated by the Taronga Conservation Society Australia using purpose-designed questionnaires provided to shark-bite victims or witnesses, media reports, and information provided by the department responsible for fisheries in each Australian state (including the Northern Territory). The dataset includes provoked and unprovoked bites from fresh, brackish, and marine waters in Australia. Data span 22 suspected shark species. This dataset will be publicly available, and can be used by analysts to decipher environmental, biological, and social patterns of shark bites in Australia. The information will aid scientists, conservationists, authorities, and members of the public to make informed decisions when implementing or selecting mitigation measures.
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Affiliation(s)
- Madeline Riley
- Southern Shark Ecology Group, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia.
- Global Ecology Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia.
| | - Phoebe Meagher
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, New South Wales, 2088, Australia
| | - Charlie Huveneers
- Southern Shark Ecology Group, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Jacob Leto
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, New South Wales, 2088, Australia
| | - Victor M Peddemors
- NSW Department of Primary Industries, Fisheries, Sydney Institute of Marine Science, Mosman, Sydney, NSW, 2088, Australia
| | - David Slip
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, New South Wales, 2088, Australia
| | - John West
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, New South Wales, 2088, Australia
| | - Corey J A Bradshaw
- Global Ecology Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
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Niella Y, Peddemors VM, Green M, Smoothey AF, Harcourt R. A “Wicked Problem” Reconciling Human-Shark Conflict, Shark Bite Mitigation, and Threatened Species. FRONTIERS IN CONSERVATION SCIENCE 2021. [DOI: 10.3389/fcosc.2021.720741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Conservation measures often result in a “wicked problem,” i.e., a complex problem with conflicting aims and no clear or straightforward resolution without severe adverse effects on one or more parties. Here we discuss a novel approach to an ongoing problem, in which actions to reduce risk to humans, involve lethal control of otherwise protected species. To protect water users, nets are often used to catch potentially dangerous sharks at popular bathing beaches, yet in Australian waters one of the targeted species, the white shark (Carcharodon carcharias) is listed as Vulnerable, while bycatch includes the Critically Endangered grey nurse shark (Carcharias taurus). Recent, highly publicised, shark attacks have triggered demands for improved bather protection, whilst welfare and conservation organisations have called for removal of lethal measures. This leaves management and policy makers with a wicked problem: removing nets to reduce impacts on threatened species may increase risk to humans; or leaving the program as it is on the premise that the benefits provided by bather protection are greater than the impact on threatened and protected species. We used multivariate analysis and generalised additive models to investigate the biological, spatial-temporal, and environmental patterns influencing catch rates of threatened and of potentially dangerous shark species in the New South Wales shark nets over two decades to April 2019. Factors influencing catches were used to develop a matrix of potential changes to reduce catch of threatened species. Our proposed solutions include replacing existing nets with alternative mitigation strategies at key beaches where catch rate of threatened species is high. This approach provides stakeholders with a hierarchy of scenarios that address both social demands and threatened species conservation and is broadly applicable to human-wildlife conflict scenarios elsewhere.
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