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Global shark attack hotspots: Identifying underlying factors behind increased unprovoked shark bite incidence

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... Trends in unprovoked shark bites are changing globally. Percapita risk is decreasing in some regions (Ferretti et al., 2015), is unchanged in others (Midway et al., 2019), whereas a few locations have increasing occurrence and probabilities of shark bites (Chapman and McPhee, 2016;Riley et al., 2022). However, the overall number of shark bites is steadily increasing (Chapman and McPhee, 2016;Bradshaw et al., 2021). ...
... Percapita risk is decreasing in some regions (Ferretti et al., 2015), is unchanged in others (Midway et al., 2019), whereas a few locations have increasing occurrence and probabilities of shark bites (Chapman and McPhee, 2016;Riley et al., 2022). However, the overall number of shark bites is steadily increasing (Chapman and McPhee, 2016;Bradshaw et al., 2021). Over the past four decades, the annual number of shark bites on humans in Australia has risen from 50 unprovoked bites between 1980and 1990, to 190 between 2010(Riley et al., 2022. ...
... The sporadic and infrequent nature of human-shark interactions makes it difficult to determine the underlying causes of these events. However, the factors typically hypothesized include growth in human population size and increased ocean use (Burgess, 2009), habitat destruction and modification, lower water quality, changing weather patterns and climate change , altered abundance and distribution of prey (potentially shifting shark distributions toward more human-populated areas) (Fitzpatrick et al., 2012), and increasing shark abundance (Chapman and McPhee, 2016;Afonso et al., 2017;Meyer et al., 2018;Bradshaw et al., 2021). The development of shark-bite mitigation measures arose after the sinking of World War II ships and the resulting shark-bite related injuries and deaths of crew members (Gilbert, 1977). ...
Article
While personal electric deterrents can reduce the risk of shark bites, evidence for the efficacy of other products is limited. We assessed two versions of a novel electric deterrent-80 and 150 volts (V)-designed to protect a large area (8 m deep × 6 m wide) or to be linked together for greater spatial coverage. We did 116 experimental trials on 43 white sharks (Carcharodon carcharias) to assess: (a) percentage of baits taken; (b) distance between bait and shark; (c) number of passes; and (d) whether sharks reacted to the deterrent. The proportion of baits taken was reduced by 24% (80 V) and 48% (150 V), although the high variance of the effect coefficient precluded statistical differentiation. Only the 150-V deterrent increased the distance between bait and shark (control: 1.59 ± 0.28 m versus active deterrent: 3.33 ± 0.33 m), but both versions increased the likelihood of a reaction (average reaction distance: 1.88 ± 0.14 m). Results were similar whether we measured distances using stereo-cameras or estimated them in situ, suggesting that stereo-cameras might not be necessary to quantify distances between sharks and baits. Our findings provide more evidence that electric deterrents can reduce the risk of shark bite, but the restricted efficacy limits the suitability of this device.
... Parmi la trentaine d'espèces de requins considérées comme dangereuses ou potentiellement dangereuses pour l'homme, une vingtaine sont répertoriées en Nouvelle-Calédonie : [2,18,23,28,32,46,51] (Tableau II pour les noms vernaculaires). Le risque de rencontre, voire d'attaque, apparaît dépendant des activités humaines, possiblement du fait de l'augmentation de la fréquentation du lagon [9,37]. De récentes attaques, pour certaines aux abords de Nouméa, sont à l'origine d'une préoccupation des autorités locales vis-à-vis de ce type d'accident, laquelle se traduit par une volonté de définir un plan de « gestion » du risque [1]. ...
... L'explication communément avancée de cette augmentation par l'augmentation de la population humaine et, par voie de conséquence, par celle du nombre d'humains exposés au risque mérite d'être discutée [16,43]. Cette augmentation est plus rapide que celle de la population humaine [37], encore que des corrélations avec des variations du nombre d'usagers du milieu matin, tels que les baigneurs, aient été localement établies [9]. L'augmentation de la population calédonienne pourrait en partie expliquer celle du nombre d'attaques puisqu'en toute logique, le nombre d'usagers du milieu marin exposés aux contacts avec les requins est corrélé à l'augmentation de la population humaine. ...
... La démographie des populations locales du requin tigre et du requin bouledogue, qui sont les prédateurs le plus fréquemment impliqués dans les attaques en Nouvelle-Calédonie est, quant à elle, mal connue. D'autres facteurs sont susceptibles d'intervenir, comme la modification de l'habitat, d'origine naturelle ou anthropique, les fluctuations d'abondance de proies, le changement climatique, la modification de la qualité (turbidité, salinité) de l'eau, ou l'augmentation locale du trafic maritime [9,37]. Il semblerait qu'un abord de la problématique au niveau local soit plus pertinent que les considérations d'ordre général, à l'échelle du monde ou d'un pays, et que celui-ci doive prendre en compte la distribution des espèces de requins localement présentes et les facteurs environnementaux susceptibles de favoriser les attaques [38]. ...
Article
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Background and objectives: Recent shark attacks in New Caledonia have prompted local authorities to elaborate a risk-management plan. The objective of the present paper is to produce detailed data on shark attacks that occurred in New Caledonian waters for the last few decades, as well as on the injuries of the victims, in order to inform rescue and medical services as well as authorities in charge of educating the public and providing security. Methods: Incidents involving sharks and humans in New Caledonia for the last six decades were included into a database. Sharks were tentatively identified to species according to the shape, size and other external characteristics of injuries to the victims, together with witness accounts. The severity of shark bites was evaluated against the scale proposed by A.K. Lentz and co-authors (Am Surg. 2010;76:101-6). Results: Sixty-seven shark-attack cases were recorded in New Caledonia from 1958 to 2020, of which 13 were lethal. The majority of the attacks concerned spearfishers and freedivers collecting invertebrates (58.5% of total). In the last decades, shark attacks may have increased towards bathers, swimmers and snorkelers (18.5%), and people taking part in water sports including surf, kitesurf, windsurf and SUP foil (14%). One scuba diver was also attacked (1.5%). Twenty attacks including 8 lethal ones were ascribed to the tiger shark Galeocerdo cuvier; 14 attacks including 2 lethal ones to the bull shark Carcharhinus leucas; 2 attacks including 1 lethal to the great white shark Carcharodon carcharías. The lethality of attacks was almost one in five, above the global average. Conclusions: Feeding incentive appeared to be a frequent factor triggering attacks. The education of the public should be promoted as a preventive measure aiming to reduce the risk of such accidents.
... Globally, the frequency of unprovoked shark bite has been increasing (McPhee, 2014). Whilst an increase in the number of water users over time contributes to this trend, it does not explain it entirely (Chapman and McPhee, 2016). Environmental factors which influence shark distribution and behavior such as ocean temperatures, the distribution and abundance of prey, and habitat changes are potential influences (Amin et al., 2012;McPhee, 2014;Chapman and McPhee, 2016;Lagabrielle et al., 2018;Lee et al., 2018;Ryan et al., 2019). ...
... Whilst an increase in the number of water users over time contributes to this trend, it does not explain it entirely (Chapman and McPhee, 2016). Environmental factors which influence shark distribution and behavior such as ocean temperatures, the distribution and abundance of prey, and habitat changes are potential influences (Amin et al., 2012;McPhee, 2014;Chapman and McPhee, 2016;Lagabrielle et al., 2018;Lee et al., 2018;Ryan et al., 2019). While the probability of an unprovoked shark bite remains low, the vivid nature of a shark bite ensures a high degree of media reporting and public concern (Neff, 2012;McPhee, 2014;Simmons and Mehmet, 2018). ...
... Managers should also be aware of biophysical factors associated with local bathing or surfing areas that may increase the risk of a bite. Examples include proximity of bathing or surfing areas to deeper channels, estuary mouths or anthropogenic discharges (Blaison et al., 2015;Ryan et al., 2019); fishing activities (Lippmann, 2018); and high abundance of marine mammals and/or the occurrence of marine mammals that are washed-up dead or stranded on beaches (Sprivulis, 2014;Chapman and McPhee, 2016;Lippmann, 2018). If the risk of occurrence of dangerous sharks is abnormally high, managers may need to implement increased public protection measures, including initiating or upgrading some of those discussed, or even implementing temporary closure of the area to water users. ...
Article
Responses to unprovoked shark bite involve public policies and management approaches that contend with the needs of public safety and the responsibility to protect threatened species. In Australia (Queensland and New South Wales) and South Africa, methods that aim to capture and kill large sharks adjacent to popular beaches are a long-standing approach aimed at reducing the risk of shark bite. This paper reviews non-lethal alternatives to catch and kill methods, and suggests optimal conditions for non-lethal systems that will assist policy makers and beach authorities in choosing public safety responses that can be applied at the ocean beach scale. Deployment needs to be strategic with sufficient knowledge of their likely effectiveness under local conditions. At this stage we believe there is no single approach universally applicable to ocean beaches where unprovoked shark bite occurs, although well considered and locally appropriate mitigation measures can reduce risk.
... Sharks are a prime example of such species. Although the probability of a shark biting a human is extremely low (Midway et al., 2019), the frequency of shark bites has increased in some locations over the last three decades (Chapman & McPhee, 2016). Any increase in shark-human incidents leads to disproportionate media coverage, drawing public interest and often escalating public concerns (Chapman & McPhee, 2016;Hardiman et al., 2020;Ryan et al., 2019). ...
... Although the probability of a shark biting a human is extremely low (Midway et al., 2019), the frequency of shark bites has increased in some locations over the last three decades (Chapman & McPhee, 2016). Any increase in shark-human incidents leads to disproportionate media coverage, drawing public interest and often escalating public concerns (Chapman & McPhee, 2016;Hardiman et al., 2020;Ryan et al., 2019). In Australia, a number of shark bite clusters occurred in the last decade, where more than one person was bitten over a relatively short period in a given area. ...
... The rise in shark bite incidents and, in particular, what drives these clusters has been a topic of considerable debate. In part, this is attributed to human population growth and the concomitant increase in the number of people participating in water-based activities (Chapman & McPhee, 2016). It is predictable that the more people in the water, the greater the chance of negative shark-human interactions, but an increase of on-water activities such as fishing and live-aboard boating can also increase the chances of attracting sharks to areas heavily used by humans (Mitchell et al., 2020). ...
Article
Full-text available
Abstract Shark bites are of high public concern globally. Information on shark occurrence and behaviour, and of the effects of human behaviours, can help understand the drivers of shark‐human interactions. In Australia, a number of shark bite clusters occurred over the last decade. One of these took place in Cid Harbour the Whitsundays, Queensland, a region for which little was known about the shark community. Here, we describe and evaluate the research in response to that shark bite cluster. Fishing methods, acoustic and satellite tracking, and baited remote underwater video cameras (BRUVs) were used to identify the shark species using Cid Harbour, estimate relative abundance, and describe habitat use and residency. Side‐scan sonar and BRUVs were also used to assess prey availability. Recreational users were surveyed to understand human behaviour and their awareness and perceptions of ‘Shark Smart’ behaviours. This allowed shark occurrence and behaviour to be interpreted in the context of human behaviours in the Harbour. Eleven shark species were identified. Relative abundance was not unusually high, and residency in Cid Harbour was typically low. For example, 79% of acoustically tagged sharks visited the harbour on
... Some human-wildlife interactions, especially shark attacks, attract widespread attention and media reports [2]. This results both into a public perception of the probability of an attack much greater than it actually is, and the implementation of measures to mitigate the risk following public concerns [3,4]. Recent data demonstrates an increase (although disputed; see [5]) of the frequency of unprovoked shark bites (sensu [2]; [6]), which may be linked to the better recording of incidents [1], and to many socio-ecological interacting factors, such as the increase of human nautical activities and ecotourism, changes in the abundance of shark preys, or predator and ecosystem shifts [1,2,4,[6][7][8][9]. ...
... This results both into a public perception of the probability of an attack much greater than it actually is, and the implementation of measures to mitigate the risk following public concerns [3,4]. Recent data demonstrates an increase (although disputed; see [5]) of the frequency of unprovoked shark bites (sensu [2]; [6]), which may be linked to the better recording of incidents [1], and to many socio-ecological interacting factors, such as the increase of human nautical activities and ecotourism, changes in the abundance of shark preys, or predator and ecosystem shifts [1,2,4,[6][7][8][9]. ...
... Over the last 40 years, about 75-100 unprovoked shark attacks on humans were recorded each year, from almost 60 countries and territories [10]. However, the majority (>80%) have occurred in six of them, often referred as "global shark attack hotspots": the United States, South Africa, Australia, Brazil, the Bahamas and Reunion Island [4,6]. Although most of these interactions resulted in no or minor injuries, similar to dog bites, some caused more serious trauma or fatalities (e.g. ...
Article
Each year, 75-100 unprovoked shark attacks on humans are recorded, most of them resulting in no or minor injuries, while a few are fatal. Often, shark identification responsible for attacks relies on visual observations or bite wound characteristics, which limits species determination and preclude individual identification. Here, we provide two genetic approaches to reliably identify species and/or individuals involved in shark attacks on humans based on a non-invasive DNA sampling (i.e. DNA traces present on bite wounds on victims), depending on the knowledge of previous attack history at the site. The first approach uses barcoding techniques allowing species identification without any a priori, while the second relies on microsatellite genotyping, allowing species identification confirmation and individual identification, but requiring an a priori of the potential species involved in the attack. Both approaches were validated by investigating two shark attacks that occurred in Reunion Island (southwestern Indian Ocean). According to both methods, each incident was attributed to a bull shark (Carcharhinus leucas), in agreement with suggestions derived from bite wound characteristics. Both approaches appear thus suitable for the reliable identification of species involved in shark attacks on humans. Moreover, microsatellite genotyping reveals, in the studied cases, that two distinct individuals were responsible of the bites. Applying these genetic identification methods will resolve ambiguities on shark species involved in attacks and allow the collection of individual data to better understand and mitigate shark risk.
... Unprovoked shark bites (also framed as 'attacks') along coastal beaches are a HWC that occurs globally, but is most often reported in Australia, South Africa, North America, Brazil and Reunion Island [11,12]. Although shark bite incidents are statistically rare [13], these events are highly traumatic for those directly involved, and they can be traumatic for those indirectly connected (i.e. ...
... Just under half of the respondents were concerned about unwanted shark interactions with 60% believing they were near sharks while they are in the water. This level of concern is not consistent with the low number of human-shark conflicts occurring annually [11,18]. However, research into public perceptions reveals that beach users often overestimate the risk of shark incidents [15]. ...
Article
Management of human-wildlife conflict is often challenging and complex, particularly when the conflict involves sharks. New technologies are being trialled in New South Wales, on Australia's east coast, to accommodate the community demand for increased beach-user protection that does not harm marine wildlife. Drones (or unmanned aerial vehicles), are one of a suite of potential tools that can address both these demands. We released an online survey to assess beach-user perceptions and attitudes toward drones on NSW beaches as a shark surveillance tool. From 439 respondents, we found the use of drones on coastal beaches was accepted by the majority of people surveyed (88%) due to perceptions of reduced impact on sharks, and the relatively low cost. Drone surveillance was also the preferred approach for bather protection overall. Arguably the most vulnerable beach-user group for a shark bite incident, surfers, claimed the highest level of awareness of the use of drones for shark surveillance, but also indicated lower confidence in their utility compared to other groups. The study demonstrates an overall social licence regarding the use of drones for shark surveillance purposes, with the levels of support likely to increase with further public education efforts and improvements to the efficacy of drone-based surveillance.
... Increasing coastal human populations and aquatic activities have contributed to a rise in the global number of shark bites and stings from stingrays (Chapman & McPhee 2016), fueling public perception of increasing risk (Crossley et al. 2014, Sabatier & Huveneers 2018, even though risks from elasmobranchs remain low (e.g. Ferretti et al. 2015). ...
... Actual risk is geographically highly variable (Midway et al. 2019). Studies to date show per capita risk decreasing in some regions (Ferretti et al. 2015) and remaining unchanged in others (Midway et al. 2019), while a few locations have emerged as hotspots showing increasing occurrence and probabilities of shark bites (Chapman & McPhee 2016). Quantifying ocean activity and its effect on shark incidents, which differs from the common proxy of total population size, is crucial for estimating the probability of shark bites and remains a challenge (Ferretti et al. 2015). ...
Article
Full-text available
Over the past 4 decades there has been a growing concern for the conservation status of elasmobranchs (sharks and rays). In 2002, the first elasmobranch species were added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Less than 20 yr later, there were 39 species on Appendix II and 5 on Appendix I. Despite growing concern, effective conservation and management remain challenged by a lack of data on population status for many species, human−wildlife interactions, threats to population viability, and the efficacy of conservation approaches. We surveyed 100 of the most frequently published and cited experts on elasmobranchs and, based on ranked responses, prioritized 20 research questions on elasmobranch conservation. To address these questions, we then convened a group of 47 experts from 35 institutions and 12 countries. The 20 questions were organized into the following broad categories: (1) status and threats, (2) population and ecology, and (3) conservation and management. For each section, we sought to synthesize existing knowledge, describe consensus or diverging views, identify gaps, and suggest promising future directions and research priorities. The resulting synthesis aggregates an array of perspectives on emergent research and priority directions for elasmobranch conservation.
... The occurrence of negative direct human-nature interactions varies at multiple spatial (from local to regional, and national to international) and temporal scales ( Over the last few decades, there has been a growing trend in some kinds of negative direct human-nature interactions such as snakebites (Chippaux, 2017), shark bites (Chapman & McPhee, 2016;McPhee, 2014), attacks by large carnivores (Bombieri et al., 2019;Penteriani et al., 2016), invertebrate interactions (Araújo et al., 2017;CDC, 2019;Chippaux, 2015) and fall-related accidents in mountains (see Figure 1). The so-called 'expansion of negative experience' (Soga & Gaston, 2022) is found in both developed and developing F I G U R E 2 Examples of negative direct human-nature interactions across three dimensions to their typology (frequency, intensity and consistency). ...
... tive direct human-nature interactions often occur together with more intense positive ones. For example, there is considerable evidence that the majority of large carnivore attacks in higher income countries occur when people engage with high-quality nature-based activities, including hiking and camping in wilderness areas (e.g.Bombieri et al., 2019;Chapman & McPhee, 2016;West, 2011). This implies the existence of a 'trade-off' between positive and negative direct humannature interactions, raising significant challenges for policy-makers and practitioners as to how best to maximise the benefits of direct humannature interactions while minimising their costs.Third, it would seem valuable to understand how the ongoing loss of biodiversity, as well as associated conservation programs, can alter the occurrence of negative direct human-nature interactions. ...
Article
Full-text available
The human health benefits of direct sensory interactions with nature (hereafter direct human–nature interactions) are increasingly recognised. However, these interactions can also have various negative health and well-being impacts on people, some of which may be severe. Compared to positive ones, there has been relatively little investigation of such negative direct human–nature interactions beyond the medical literature, and what has been done is widely scattered across disciplines. Here, we provide an overview of the typology, characteristics and dynamics of negative direct sensory interactions with nature and suggest management implications and future research directions. We highlight the breadth of forms that negative direct human–nature interactions occur, and evidence that the incidences of some have recently grown rapidly in many parts of the world. Our review also suggests that more intense negative direct human–nature interactions can sometimes occur simultaneously or sequentially with more positive ones, and there may be trade-offs between the two. Such serious implications highlight the importance of focusing research and public policy on improving the understanding of negative direct human–nature interactions, taking a more balanced view of the benefits and costs of nature experiences, and developing appropriate mitigation strategies. Read the free Plain Language Summary for this article on the Journal blog. © 2022 The Authors. People and Nature published by John Wiley & Sons Ltd on behalf of British Ecological Society.
... One emblematic issue with elasmobranch conservation resides within the boundaries of tourism and recreational activities: sometimes, in a few particular regions, a handful of shark species pose a risk to humans (Chapman & McPhee, 2016). Unfortunately, this situation may lead to human-shark conflicts, for which shark culling is often identified as a solution (Meeuwig & Ferreira, 2014), despite recent global analyses showing this to be the main contributor to reef shark population collapse (MacNeil et al., 2020). ...
... One of the world's shark bite hotspots (McPhee, 2014) is the small oceanic island of Reunion, situated over 600 km off the eastern coast of Madagascar, where shark bite incidence rate has risen sharply over the last decade (Chapman & McPhee, 2016), in part as a result of the rapid development of tourism and the increased popularity of surfing (Lagabrielle et al., 2018). Concerns over the potential negative impacts of sharks on watersports and other coastal leisure activities have simultaneously prompted the activation of a shark control programme, and an unprecedented level of research effort on the status of the elasmobranch fauna around the island (Blaison et al., 2015;Guyomard et al., 2019), mostly focused on the two species responsible for the unprovoked bites, bull shark (Carcharhinus leucas) and tiger shark (Galeocerdo cuvier) (Ballas, Saetta, Peuchot, Elkienbaum, & Poinsot, 2017;Guyomard et al., 2020). ...
Article
Full-text available
Sharks embody several major aspects of modern marine management: they are traditionally antagonized, exploited or by‐caught by humans, typically vulnerable to extirpation, pursued as luxury food, yet valued as wildlife and essential as top‐down regulators in marine food webs. Due to their generally large size, elusiveness, high mobility, and potentially dangerous nature, elasmobranchs pose substantial technical challenges to biodiversity monitoring, which prompted recent efforts to harness the power of environmental DNA (eDNA) as a noninvasive survey method for these taxa. Here we deployed an elasmobranch‐specific metabarcoding assay to characterize shark and ray diversity around Reunion Island, during the austral summer, detecting at least 14 species and a strong overall correlation between frequency of species detection and read abundance. Over 90% of sequence reads belonged to three large predators: scalloped hammerhead (Sphyrna lewini), tiger shark (Galeocerdo cuvier) and bull shark (Carcharhinus leucas). While the importance of tiger and bull sharks is well established in Reunion Island, and a major focus of the local shark control program, the prevalence and abundance of scalloped hammerhead has so far been grossly neglected. We also confirm the absence of typical “tropical reef sharks” around the island and reveal an important temporal fluctuation in tiger shark during the study period. Collectively, results show how eDNA can help circumvent barriers, bias and drawbacks associated with monitoring shark populations using visual and capture‐based techniques, and generate spatial and temporal biodiversity data on these species for rapid consideration by marine environmental managers.
... The study was carried out in South Africa, where beach-based recreation and tourism represent an asset to the national economy (McKenna, Williams, & Cooper, 2011). South Africa is the country that had the third-largest number of interactions reported between ocean users and sharks in 1960 to 2015, although only 16% of these interactions were fatal to humans (Chapman & McPhee, 2016;Midway, Wagner, & Burgess, 2019). ...
... Half of the participants declared themselves afraid of sharks. However, most of them did not perceive sharks as a risk to water users, albeit know of locally present shark species, some of which are involved in shark bite incidents (Chapman & McPhee, 2016). ...
Article
Beach-based recreation is an important ecosystem service. Its management relies on balancing human needs and the integrity of coastal ecosystems. Management, however, can be unbalanced in favor of the former, for example, through bather safety programs that are lethal to sharks and other marine species. The promotion of eco-friendlier shark control strategies is underpinned by an understanding of human engagement with shark hazard mitigation (SHM). This study used a questionnaire survey to assess beach visitors’ (N = 843) perceptions of SHM at locations implementing lethal and nonlethal shark control in South Africa. Perceptions were dependent on demography, water use, attitudes towards sharks, and local contexts. Elements requiring attention encompassed the role of fear in shaping perceptions, limited awareness of local SHM , misunderstanding of the ecological harm of some mitigation types, and personal responsibility in mitigating risks. Strategies to garner support for pro-shark beach-based recreation are discussed.
... Increasing coastal human populations and aquatic activities have contributed to a rise in the global number of shark bites and stings from stingrays (Chapman & McPhee 2016), fueling public perception of increasing risk (Crossley et al. 2014, Sabatier & Huveneers 2018, even though risks from elasmobranchs remain low (e.g. Ferretti et al. 2015). ...
... Actual risk is geographically highly variable (Midway et al. 2019). Studies to date show per capita risk decreasing in some regions (Ferretti et al. 2015) and remaining unchanged in others (Midway et al. 2019), while a few locations have emerged as hotspots showing increasing occurrence and probabilities of shark bites (Chapman & McPhee 2016). Quantifying ocean activity and its effect on shark incidents, which differs from the common proxy of total population size, is crucial for estimating the probability of shark bites and remains a challenge (Ferretti et al. 2015). ...
Article
Full-text available
Over the past 4 decades there has been a growing concern for the conservation status of elasmobranchs (sharks and rays). In 2002, the first elasmobranch species were added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Less than 20 yr later, there were 39 species on Appendix II and 5 on Appendix I. Despite growing concern, effective conservation and management remain challenged by a lack of data on population status for many species, human−wildlife interactions, threats to population viability, and the efficacy of conservation approaches. We surveyed 100 of the most frequently published and cited experts on elasmobranchs and, based on ranked responses, prioritized 20 research questions on elasmobranch conservation. To address these questions, we then convened a group of 47 experts from 35 institutions and 12 countries. The 20 questions were organized into the following broad categories: (1) status and threats, (2) population and ecology, and (3) conservation and management. For each section, we sought to synthesize existing knowledge, describe consensus or diverging views, identify gaps, and suggest promising future directions and research priorities. The resulting synthesis aggregates an array of perspectives on emergent research and priority directions for elasmobranch conservation.
... This issue is highlighted in the management of human-shark conflicts. At a global scale, an increase in the number of shark bites has been observed, yet the individual risk for beach users is simultaneously decreasing due to the number of ocean users increasing even more rapidly (McPhee, 2014;Ferretti et al., 2015;Chapman & McPhee, 2016;Midway, Wagner & Burgess, 2019). When compared with other types of human-wildlife interactions, the number of shark bites is low, yet they receive massive media exposure (Muter et al., 2013) and political attention (Neff, 2012). ...
Article
• Knowledge about spatial and temporal variability in the distribution and abundance of predators is necessary to adapt measures to mitigate human–wildlife interactions. • Acoustic telemetry and network analyses were used to investigate the spatial ecology of bull sharks, the species responsible for most shark bites in Reunion Island, one of the world's shark bite hotspots. • The west coast of the island was not used uniformly by every individual, with size predicting the movements of sharks along the coast. • Node-based metrics – closeness, node strength, and cumulated continuous residency times – derived from up to 181 monthly movement networks from 20 individuals, revealed that smaller sharks (<250 cm total length) primarily used the south-west coast while larger individuals spent most of their time in the northern region with regular visits to multiple areas along the coast. • This study provides essential knowledge on bull shark behaviour and central areas used at different periods of the year, which correlates well with the dynamics of observed shark bites. Our approach provides a non-invasive alternative to help predicting and anticipating human–shark conflicts and avoid shark culling programmes detrimental to the conservation of large predators such as sharks.
... To reduce shark incidents, shark hazard-mitigation strategies have been adopted by the United States, South Africa, Australia, Brazil and Reunion Island, which are regarded as shark bite "hotspots" [150]. Such strategies generally rely on culling programs aiming at reducing the local abundance of hazardous species, which have typically been implemented by deploying shark nets, longlines and drumlines [151][152][153]. ...
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One of the biggest challenges is to determine the deployment and navigation of the drones to benefit the most for different applications. Many research questions have been raised about this topic. For example, drone-enabled wildlife monitoring has received much attention in recent years. Unfortunately, this approach results in significant disturbance to different species of wild animals. Moreover, with the capability of rapidly moving communication supply towards demand when required, the drone equipped with a base station, i.e., drone-cell, is becoming a promising solution for providing cellular networks to victims and rescue teams in disaster-affected areas. However, few studies have investigated the optimal deployments of multiple drone-cells with limited backhaul communication distances. In addition, the use of autonomous drones as flying interactors for many real-life applications has not been sufficiently discussed. With superior maneuverability, drone-enabled autonomous aerial interacting can potentially be used on shark attack prevention and animal herding. Nevertheless, previous studies of autonomous drones have not dealt with such applications in much detail. This report explores the solutions to all the mentioned research questions, with a particular focus on the deployment and navigation of the drones. Simulations have been conducted to verify the effectiveness of the proposed approaches. We believe that our findings in this report shed new light on the fundamental benefits of autonomous civilian drones.
... Globally, unprovoked shark bites on humans are rare events, but nevertheless generate substantial anguish for those involved and can create negative cascading social effects among the broader community (Chapman and McPhee, 2016;Hardiman et al., 2020). Most applied strategies to manage shark bites on humans can be encapsulated within three broad categories. ...
Article
The effects of decomposing shark tissue on catches of benthic longlines targeting various carcharhinids were assessed to inform possible use as a semiochemical shark deterrent. During 15 nights fishing, four benthic longlines (each comprising 18–30 hooks baited with mullet, Mugil cephalus) were deployed to 12–56 m overnight for 12–21 h off eastern Australia. Two of the longlines had 2.0–3.0 kg of decomposing shark tissue placed into porous cylindrical canisters (520 × 105 mm polyvinyl chloride) secured to the mainline mostly between every three hooks (15–20 m apart), while the other two longlines had empty canisters. In total, 150 fish were caught, comprising 14 species of elasmobranchs and especially tiger sharks, Galeocerdo cuvier (31% of total). The decomposing shark tissue in the canisters had no effects on catches of any species or groups, with variability among most attributed to fishing depth (positive relationship) and also soak time (negative) for carcharhinids and G. cuvier. Irrespective of the contents of the canisters and the lack of any semiochemical effects, there was some evidence of fewer sharks caught on adjacent hooks as moonlight increased, and possibly because of a visual response. There was no depredation of any decomposing shark tissue in the canisters, but three juvenile hooked sharks were substantially depredated, and presumably by larger individuals. Most (∼70%) of the remaining hooked sharks survived. While this study showed no repelling effects of decomposing shark tissue, the conclusions are restricted to the experimental conditions, including the source of tissue and the distance between hooks, which might be used as upper limit in any future work assessing for effects.
... Shark bite mitigation policy in Australia over the last century has frequently focused on strategies that either directly reduce the number of dangerous sharks or may indirectly result in the fatality of sharks and other marine life [5]. Today, there is vocal disapproval from sections of the community in states where these strategies (e.g. ...
Article
Little is known about relationships between features of shark-human interactions and community expectations of authorities to respond. Previous research reports attitudes to wildlife management are influenced by context. This study comprised three phases. Phase one analysed social media related to shark management, identifying five commonly discussed variables in shark-human interaction contexts likely to influence attitudes towards management response. These context variables were: Level of human use of location; recency of other bites at the location; activity of victim; time of day; severity of harm to victim. Phase two used focus groups with ocean users to validate the Phase one context variables, and refine scenarios and management response options for Phase three, an experimental survey measuring the influence of context variables on New South Wales ocean user attitudes to management responses. The article focuses on Phase three, which randomly assigned participants (N = 1769) one of 48 shark-human interaction scenarios comprising different manipulations of the five context variables. Participants rated support for 20 shark management response options. Contrary to expectations, context variables did not influence attitudes to shark management responses. There was almost unanimous support for education and research as preferred response to managing risk from sharks, and little support for invasive strategies perceived to harm marine life, such as shark nets and drumlines. Support for shark management responses decreased as invasiveness of the response increased. The findings reflect community dislike of 'knee-jerk' policy making, indicating that attitudes to shark management are relatively stable, and do not fluctuate in response to specific incidents.
... The most problematic shark species include the white shark (Carcharodon carcharias Linnaeus 1758), tiger shark (Galeocerdo cuvier Péron & Lesueur 1822), and bull shark (Carcharhinus leucas Müller & Henle 1839), which are responsible for ~56% of all bites and ~98% of all fatalities over the last three decades globally (McPhee, 2014). These three species co-occur in some temperate and subtropical waters around the world, including the eastern seaboard of Australia, a region recognized as one of the world's shark attack hotspots (Chapman & McPhee, 2016). ...
Article
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The number of human–shark interactions has increased worldwide during the past decade resulting in injuries and fatalities. In Australia, the white shark (Carcharodon carcharias), tiger shark (Galeocerdo cuvier), and bull shark (Carcharhinus leucas) are responsible for the majority of fatal incidents. On the southeast coast of Australia, monitoring programs currently rely on SMART (Shark‐Management‐Alert‐in‐Real‐Time) drumlines and mesh nets to catch, tag, and monitor shark movement. However, these methods are laborious, costly, and involve the capture of only a fraction of the total shark population. Here, we develop a multiplex environmental DNA assay capable of detecting all three shark species simultaneously from water samples by targeting conserved but specific mitochondrial sequences that are characteristic of each species. The specificity of the assay was validated by testing for cross‐amplification across a range of non‐target but co‐occurring shark species from eastern Australia. We test the sensitivity of the assay on water samples collected from shark capture events and sites where these shark species are known to frequent, and undertake DNA sequencing on positive samples to confirm species haplotype authenticity. Samples collected from one of these sites also demonstrate that eDNA detections are dependent on shark activity in the area. This assay will allow for rapid detection of DNA from each shark species in water samples, providing a cost‐effective alternative for monitoring sharks along the east coast of Australia and potentially elsewhere.
... Thus, declining shark populations due to overfishing and climate change are a significant cause for concern (Chin et al. 2010; Strickland 2017). However, sharks also present a water safety risk in many areas of the world, with the number of unprovoked shark bites, while rare, on the rise (Chapman and McPhee 2016). Shark encounters or a perceived change in the risk of encounters, for example through media coverage, can alter the way people use and enjoy the ocean for swimming and water sports (Gibbs and Warren 2015;McCagh et al. 2015) potentially impacting on human health. ...
Article
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The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named ‘Command and (out of) Control’, focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called ‘Living and Connecting’, emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the ‘Living and Connecting’ scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society’s diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the United Nations Decade of Ocean Science. Graphic abstract
... Sharks are considered a threat to humans as sharks are one of the ocean's biggest predators [1]. The sharks' teeth and jaws are deadly, but mostly the great white, the oceanic whitetip, the tiger and the bull shark are accountable for the fatal attacks on humans [2]- [3]. Statistics show that the USA and Australia are the most sharks infested countries in the world [4]. ...
... Unprovoked shark bite incidence is increasing world-wide. It becomes more apparent in shark attack hotspots range from the United States, South Africa, Australia, Brazil, Reunion Island and to Bahamas.Blake et al. (2016) have confirmed the increases in shark bite incidence are likely correlated to rises in human population combined with other anthropogenic related causative factors, including habitat destruction/modification, water quality degradation, climate change, and anomalous ...
Preprint
Shark unprovoked attacks consist of fatal and non-fatal cases. Numerous cases have been reported involving shark species from Carcharhinus melanopterus with length of 145.5 cm to half-ton Carcharodon carcharias. Currently there are more (P < 0.05) unprovoked non-fatal cases with the average is 28.46 cases/shark species (95%CI: 3.86-53.1) than unprovoked fatal cases, which the average is 5.12 cases /shark species (95%CI: -0.075-10.3). Hence this paper seeks to select the best shark size model that correlates with the unprovoked fatal and non-fatal cases. The studied sharks consist of 24 shark species with the average length is 268.18 cm (95%CI: 230-306 cm) and the average weight is 225.42 kg (95%CI: 128-323 kg). Based on the model and as described by low values of AIC and the highest values of R2 and adjusted R2 , shark weight followed by combinations of shark weight and length produced unprovoked fatal and non-fatal cases best models. The model for explaining unprovoked fatal cases is the shark weight with high numbers of cases observed in large size shark (weight⁓fatal cases, AIC = 165.359, R2 = 0.72, Adj. R = 0.71). While for non-fatal cases, the best model is also the shark weight (weight⁓non fatal cases, AIC = 246.93, R2 = 0.63, Adj. R = 0.59).
... Despite its relatively small population, Australia is one of the world's shark bite hotspots [1] with one of the highest numbers of human-shark interactions after the USA. Australian shark attack data has been recorded since 1791. ...
Article
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The number of shark attacks resulting in fatalities and severe injuries has increased steadily over recent years. This is mainly attributed to a growing population participating in ocean sports such as swimming, diving, and surfing. To mitigate the severity of shark attacks, the current study presents a novel fibre-reinforced composite for bite protection. This material is intended for integration into neoprene wetsuits, e.g., in the form of protective pads. A suitable material must be able to withstand significant bite forces, which are concentrated within a small contact area at the tips of the shark teeth. At the same time, the material should not hinder the complex motion sequences of aquatic sports. To this end, a novel fibre-reinforced composite was created by integrating Kevlar fibres into an elastic matrix. Uni-axial testing using shark teeth replicas was conducted on a specially designed test rig to quantify the effectiveness of the novel protective material.
... Thus, declining shark populations due to overfishing and climate change are a significant cause for concern (Chin et al. 2010;Strickland 2017). However, sharks also present a water safety risk in many areas of the world, with the number of unprovoked shark bites, while rare, on the rise (Chapman and McPhee 2016). Shark encounters or a perceived change in the risk of encounters, for example through media coverage, can alter the way people use and enjoy the ocean for swimming and watersports (Gibbs and Warren 2015;McCagh et al. 2015) potentially impacting on human health. ...
... ufl.edu/shark-attacks/yearly-worldwide-summary/ Accessed on 1 July 2022); however, the number of reported shark bite incidents and fatalities has risen since records began [2], causing increasing levels of community concern [3]. The negative impacts of these incidents has led to a variety of shark hazard mitigation measures being implemented that are predominantly designed to reduce the likelihood of ocean users being bitten [4][5][6][7]. ...
Article
Full-text available
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.
... source-sink | wilderness | coadaptation | grizzly bear | demography H uman coexistence with large carnivores poses one of the greatest conservation challenges of our time. From tiger (Panthera tigris) and leopard (Panthera pardus) attacks in rural Asian villages (1), shark-attack hotspots (2), to brown bear (Ursus arctos) conflicts in urban areas of North America and Europe (3,4), carnivores pose real and perceived threats to human life, livelihoods, and property (3,4). As a result, humans kill carnivores either preemptively or in retaliation, making human-dominated areas highly lethal for many animals (5). ...
Article
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Significance The persistence of large carnivores in human-dominated landscapes will become increasingly challenging as the human footprint expands. Here, we bring together long-term demographic and behavioral data on one of the worlds’ most conflict-prone species, the brown bear, to quantify the mechanisms facilitating human–carnivore coexistence. We found that human-dominated landscapes are highly lethal, especially to young bears, until they learn to adapt to people. As bears age, they avoid times when people are most active but do not strongly avoid where people live. To sustain human–carnivore coexistence under high rates of mortality requires the influx of animals from areas with low human presence (i.e., demographic rescue). Paradoxically, our work demonstrates that connectivity leads to both coexistence and conflict.
... Although uncommon, the number of unprovoked shark bites has increased worldwide [7,40]; especially in Australia and the United States where incident rates have doubled in the last 20 years [41]. However, fatalities still represent a rare ocean hazard to beachgoers in comparison to other hazards such as drowning [57]. ...
Article
Full-text available
The future of shark mitigation worldwide, not only depends on economic and environmental considerations but on community support and acceptance of mitigation approaches. Shark mitigation strategies and policy development based on publicly held values in combination with expert knowledge is more likely to be supported and accepted by the public and society in general. In 2015, the New South Wales (NSW) government implemented a five-year Shark Management Strategy (SMS) to trial new and emerging technologies following a cluster of shark bites in 2014 and 2015 (including fatalities); most notably on the NSW north coast. The strategy aimed to increase protection of beachgoers while minimising harm to sharks and other marine animals. This paper synthesises various SMS-related social research studies to generate knowledge and improve understanding of community attitudes, support and preferences for different shark mitigation approaches trialled in the SMS. Our findings show non-invasive mitigation approaches involving shark detection and tracking, and public notifications were supported and preferred over invasive and/or lethal approaches such as nets. Drone surveillance was very highly supported (and preferred over helicopters) for being localised, having the capacity to be incorporated into beach safety operations, and with future potential for automation and the use of artificial intelligence to increase detection capability. Community education was seen as a fundamental component of shark mitigation to help people increase their ability to take personal responsibility for their own safety, improve public knowledge and understanding of sharks, and to mitigate fear; ultimately, to foster coexistence without jeopardising public safety.
... Over a 30-year period unprovoked shark bite has been recorded from 56 countries and territories, with most (84%) in the United States, South Africa, Australia, Brazil, the Bahamas and Reunion Island [3]. Many of the bites and associated fatalities have involved surfers [2,3]. White sharks (Carcharodon carcharias), tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas) account for 55.6% of all bites (including many of the fatalities) over the 30year period [3]. ...
... This article illustrates just one aspect of how human-shark interactions has become a growing interdisciplinary sub-field of human-shark relations within marine social science [26]. This emerging sub-field looking at human-shark relations relative to marine biology [27], geography [28], political science [29], conservation, film studies [30], communications [31]. This article contributes to a demonstrated "shark turn" in social science research. ...
Article
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The social and political dynamics around human–shark interactions are a growing area of interest in marine social science. The question motivating this article asks to what extent media reporting by The New York Times has engaged beyond the lexicon of “shark attack” discourse to describe human–shark interactions. It is important because different styles of reporting on human–shark interactions can influence the public’s perceptions about sharks and support for shark conservation. This media outlet is also a paper of record whose editorial style choices may influence the broader media landscape. I review reporting language from The New York Times for 10 years between 2012 and 2021 (n = 36). I present three findings: first, I argue that The New York Times has had an increased frequency in use of the term “shark bite” to describe human–shark interactions. Secondly, I find that shark “attack” is still used consistently with other narratives. Third, there appears to be an increased use of “sightings; encounter; and incident” descriptors since 2020. The implication of this is a layered approach to reporting on human–shark interactions that diversifies away from a one-dimensional shark “attack” discourse.
... As threatened marine predators that fulfill key ecological roles Rigby et al., 2019;Shea et al., 2020), understanding their natural behavior is important for species and ecosystem management. Additionally, white sharks impose risks for human safety (Chapman and McPhee, 2016), and effectively mitigating these risks is complex, but important for societal dynamics as well as shark conservation (McPhee et al., 2021;Simpfendorfer et al., 2021). In New South Wales, Australia, white sharks are caught, relocated ∼1 km offshore, and released through a non-lethal mitigation approach using Shark-Management-Alert-in-Real-Time (SMART) drumlines (Tate et al., 2021a), yet their behavioral responses to capture, and hence the implications of this strategy for both sharks and people, are unknown. ...
Article
Full-text available
Multisensor biologging provides a powerful tool for ecological research, enabling fine-scale observation of animals to directly link physiology and movement to behavior across ecological contexts. However, applied research into behavioral disturbance and recovery following human interventions (e.g., capture and translocation) has mostly relied on coarse location-based tracking or unidimensional approaches (e.g., dive profiles and activity/energetic metrics) that may not resolve behaviors and recovery processes. Biologging can improve insights into both disturbed and natural behavior, which is critical for management and conservation initiatives, although challenges remain in objectively identifying distinct behavioral modes from complex multisensor datasets. Using white sharks ( Carcharodon carcharias ) released from a non-lethal catch-and-release shark bite mitigation program, we explored how combining multisensor biologging (video, depth, accelerometers, gyroscopes, and magnetometers), track reconstruction and behavioral state modeling using hidden Markov models (HMMs) can improve our understanding of behavioral processes and recovery. Biologging tags were deployed on eight white sharks, recording their continuous behaviors, movements, and environmental context (habitat, interactions with other organisms/objects) for periods of 10–87 h post-release. Dive profiles and tailbeat analysis (as a standard, activity-based method for assessing recovery) indicated an immediate “disturbed” period of offshore movement, displaying rapid tailbeats and an average tailbeat-derived recovery period of 9.7 h, with evidence of smaller individuals having longer recoveries. However, further integrating magnetometer-derived headings, track reconstruction and HMM modeling revealed a cryptic shift to diurnal clockwise-counterclockwise circling behavior, which we argue represents compelling new evidence for hypothesized unihemispheric sleep amongst elasmobranchs. By simultaneously providing critical information toward conservation-focused shark management and understudied aspects of shark behavior, our study highlights how integrating multisensor information through HMMs can improve our understanding of both post-release and natural behavior, especially in species that are difficult to observe directly.
... Our findings can contribute to conservation strategies for threatened shark species and assist with shark management by detailing shark occurrence off popular ocean beaches. Such information can also directly contribute to optimising shark mitigation efforts to maximise their cost-effectiveness in a globally recognised hotspot for shark bites [28,35]. ...
Article
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There is still limited information about the diversity, distribution, and abundance of sharks in and around the surf zones of ocean beaches. We used long-term and large-scale drone surveying techniques to test hypotheses about the relative abundance and occurrence of sharks off ocean beaches of New South Wales, Australia. We quantified sharks in 36,384 drone flights across 42 ocean beaches from 2017 to 2021. Overall, there were 347 chondrichthyans recorded, comprising 281 (81.0%) sharks, with observations occurring in <1% of flights. Whaler sharks (Carcharhinus spp.) had the highest number of observations (n = 158) recorded. There were 34 individuals observed for both white sharks (Carcharodon carcharias) and critically endangered greynurse sharks (Carcharias taurus). Bull sharks (Carcharhinus leucas), leopard sharks (Stegostoma tigrinum) and hammerhead species (Sphyrna spp.) recorded 29, eight and three individuals, respectively. Generalised additive models were used to identify environmental drivers for detection probability of white, bull, greynurse, and whaler sharks. Distances to the nearest estuary, headland, and island, as well as water temperature and wave height, were significant predictors of shark occurrence; however, this varied among species. Overall, we provide valuable information for evidence-based species-specific conservation and management strategies for coastal sharks.
... Moreover, climate-driven alteration to the movements of large predators, such as sharks, could change their likelihood of encounters with recreational water users (Chapman & McPhee, 2016) and and/ or cause altering ecosystem dynamics through novel trophic cascades (Bastille-Rousseau et al., 2019;Hammerschlag et al., 2019;Rosenblatt et al., 2017). Although shifts have been predicted (e.g., Birkmanis et al., 2020;Hazen et al., 2013;Niella et al., 2020, empirical evidence of climate-driven shifts on the distribution or phenology of marine top predators is rare (c.f. ...
Article
Full-text available
Given climate change threats to ecosystems, it is critical to understand the responses of species to warming. This is especially important in the case of apex predators since they exhibit relatively high extinction risk, and changes to their distribution could impact predator–prey interactions that can initiate trophic cascades. Here we used a combined analysis of animal tracking, remotely sensed environmental data, habitat modeling, and capture data to evaluate the effects of climate variability and change on the distributional range and migratory phenology of an ectothermic apex predator, the tiger shark (Galeocerdo cuvier). Tiger sharks satellite tracked in the western North Atlantic between 2010 and 2019 revealed significant annual variability in the geographic extent and timing of their migrations to northern latitudes from ocean warming. Specifically, tiger shark migrations have extended farther poleward and arrival times to northern latitudes have occurred earlier in the year during periods with anomalously high sea-surface temperatures. A complementary analysis of nearly 40 years of tiger shark captures in the region revealed decadal-scale changes in the distribution and timing of shark captures in parallel with long-term ocean warming. Specifically, areas of highest catch densities have progressively increased poleward and catches have occurred earlier in the year off the North American shelf. During periods of anomalously high sea-surface temperatures, movements of tracked sharks shifted beyond spatial management zones that had been affording them protection from commercial fishing and bycatch. Taken together, these study results have implications for fisheries management, human–wildlife conflict, and ecosystem functioning.
... Globally, unprovoked shark bites are steadily increasing [58,59]. Although the individuals in the present study favoured offshore habitats, all three sharks entered nearshore coastal waters, increasing the likelihood of human-shark interactions in eastern Australian waters. ...
Article
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In eastern Australia, white sharks (Carcharodon carcharias) are targeted in shark control programs, yet the movement of subadults and adults of the eastern Australasian population is poorly understood. To investigate horizontal and vertical movement and habitat use in this region, MiniPAT pop-up satellite archival tags were deployed on three larger white sharks (340–388 cm total length) between May 2021 and January 2022. All sharks moved away from the coast after re- lease and displayed a preference for offshore habitats. The upper < 50 m of the water column and temperatures between 14–19 °C were favoured, with a diel pattern of vertical habitat use evident as deeper depths were occupied during the day and shallower depths at night. Horizontal movement consisted of north–south seasonality interspersed with periods of residency. Very little information is available for adult white sharks in eastern Australia and studies like this provide key baseline information for their life history. Importantly, the latitudinal range achieved by white sharks illu- minate the necessity for multijurisdictional management to effectively mitigate human-shark inter- actions whilst supporting conservation efforts of the species.
... Dans le milieu marin, bien que demeurant rares, les attaques concernent essentiellement les requins. Ces attaques ont été de plus en plus fréquemment rapportées ces dernières années, notamment aux Etats-Unis, en Afrique du Sud, en Australie, au Brésil, autour de l'île de la Réunion, et aux Bahamas (Chapman & McPhee, 2016). ...
Thesis
Les espèces qui se nourrissent de plantes ou d’animaux élevés ou capturés par l’homme, un comportement appelé « déprédation », entraînent souvent de graves Conflits Homme-Faune sauvage (CHF). La déprédation a été signalée dans le monde entier et, dans les écosystèmes marins, elle a été développée par de nombreux grands prédateurs se nourrissant des prises de pêche, ce qui a un impact à la fois sur les activités de pêche et les interactions écologiques. Cependant, bien que les approches écosystémiques soient de plus en plus utilisées dans la gestion des pêches, les effets de la déprédation sur l’ensemble de l’écosystème sont encore rarement considérés de manière holistique. Par conséquent, cette thèse a (i) identifié les limites, manques et priorités pour le développement d’approches de modélisation intégrant la déprédation et (ii) évalué la capacité de deux approches de modélisation existantes pour caractériser les conséquences de la déprédation marine et, plus spécifiquement, comprendre les enjeux et conditions requises pour que les activités d’exploitation halieutique et les déprédateurs marins puissent co-exister. Cette thèse est composée de cinq chapitres. Le chapitre 1 présente le contexte dans lequel s’inscrit ces travaux. Le chapitre 2 identifie les principales lacunes dans les connaissances et met en évidence les principales orientations futures pour parvenir à une inclusion efficace de la déprédation dans les études de modélisation en réalisant une revue systématique. Le chapitre 3 utilise le cadre Ecopath pour évaluer les effets de la déprédation sur l'écosystème dans une étude de cas bien documentée impliquant des mammifères marins et une pêcherie commerciale. Le chapitre 4 s'appuie sur une modélisation qualitative pour évaluer les conditions de persistance d'une ressource exploitée, d'une pêcherie et d'une espèce déprédatrice dans les systèmes marins touchés par la déprédation, et la façon dont la déprédation marine affecte les réponses à long terme à des scénarios alternatifs. Enfin, la discussion générale présentée dans le chapitre 5, fournit des recommandations qui vise à mieux comprendre et prévoir les effets de la déprédation au niveau du socio-écosystème.
... The occurrence of unprovoked shark bites has increased globally for over 30 years and Australia has been identified as a 'hotspot' 10 . Records of shark bites have been maintained in Australia since 1791. ...
Article
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The perceived and real threat of shark bites have significant direct health and indirect economic impacts. Here we assess the changing odds of surviving an unprovoked shark bite using 200 years of Australian records. Bite survivability rates for bull (Carcharhinus leucas), tiger (Galeocerdo cuvier) and white (Carcharodon carcharias) sharks were assessed relative to environmental and anthropogenic factors. Survivability of unprovoked bull, tiger and white shark bites were 62, 75 and 53% respectively. Bull shark survivability increased over time between 1807 and 2018. Survivability decreased for both tiger and white sharks when the person was doing an in water activity, such as swimming or diving. Not unsurprisingly, a watercraft for protection/floatation increased survivability to 92% from 30%, and 88% from 45%, for tiger and white sharks respectively. We speculate that survival may be related to time between injury and treatment, indicating the importance of rapid and appropriate medical care. Understanding the predictors of unprovoked bites, as well as survivability (year and water activity), may be useful for developing strategies that reduce the number of serious or fatal human-shark interactions without impacting sharks and other marine wildlife.
... Likewise, shifts in distribution patterns and range retractions may impact the revenue obtained through fsheries and tourism directly, given this group's economic value (Gallagher and Hammerschlag 2011;Hammerschlag et al., 2019;Kendrick et al. 2019), and indirectly, given their potential to modulate community response through top-down pressure (Estes et al. 2016;Ferretti et al. 2010;Heithaus et al. 2010;Nowicki et al. 2019Nowicki et al. , 2021Wild et al. 2019; see also Chapter 15). On the other hand, climate change may also potentiate negative interactions with humans, as species historically perceived as "dangerous" move into new areas (Bangley et al. 2018;Chapman and McPhee 2016). ...
Article
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Hasan V, Widodo MS. 2020. Short Communication: The presence of Bull shark Carcharhinus leucas (Elasmobranchii: Carcharhinidae) in the fresh waters of Sumatra, Indonesia. Biodiversitas 21: 4433-4439. A single subadult specimen of Bull shark Carcharhinus leucas was photographed and captured by local fisherman using casting net on June 2020 in the upper Indragiri River, Riau Province, Indonesia. Carcharhinus leucas are one of only a few species of elasmobranchs that live in both marine and freshwater environments. This species currently listed as a near-threatened species based on the IUCN Red List Status. Singel specimen identified as C. leucas by the coloration of fresh specimen: white belly and greyish back, first dorsal fin high, tip of second dorsal and caudal fins black. Meristic characters measurement results as follows: total length 102 cm; fork length 86.3 cm; preanal length 65.1 cm; pre pelvic length 51.9 cm; pre pectoral length 22.5 cm; pre-orbital length 8.3 cm; head length 25 cm; pre-first dorsal length 29.4 cm; pre-second dorsal length 56 cm, and pre-caudal length 78.1 cm. This photo is considered as the third record from freshwaters of Sumatra after in the Batang Hari River, Jambi Province in 1997, and in the Musi River, South Sumatra Province in 2019. The photographic records indicate that a single specimen of C. leucas was found in the upper Indragiri River recorded more than 150 km inland. These results enhanced the understanding of C. leucas distribution in Sumatra freshwaters. Monitoring is needed to assess the possibility of the importance of the upper Indragiri River as a migration route, nursery, and growth ground of C. leucas. Studying small scale habitat use of C. leucas is challenged by their preferred habitats in freshwaters environments with fast-changing environmental conditions. Water conditions in the upper Indragiri River, namely salinity 0‰, temperature 25-27°C, dissolved oxygen 3.9-11.1 mg/l, are ideal for A. leucas habitat.
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Conflict between humans and large predators is a longstanding challenge that can present negative consequences for humans and wildlife. Sharks have a global distribution and are considered to pose a potential threat to humans; concurrently many shark species are themselves threatened. Developing strategies for coexistence between humans and this keystone group is imperative. We assess blimp surveillance as a technique to simply and effectively reduce shark encounters at ocean beaches and determine the social acceptance of this technique as compared to an established mitigation strategy—shark meshing. We demonstrate the suitability of blimps for risk mitigation, with detection probabilities of shark analogues by professional lifeguards of 0.93 in ideal swimming conditions. Social surveys indicate strong social acceptance of blimps and preference for non-lethal shark mitigation. We show that continuous aerial surveillance can provide a measurable reduction in risk from sharks, improving beach safety and facilitating coexistence between people and wildlife.
Article
This research examines the role that fear of sharks has played in the history of St Helena Island Moreton Bay, Queensland through analysis of historical records, newspapers, photographs and literature. The article begins with Aboriginal histories of St Helena Island, colonial settlement of the region and the building of a quarantine station. An exploration of the ways in which settlers’ fear of sharks supported the detention of prisoners in the St Helena Island Penal Establishment follows. The research finds that the warders’ shark-proof swimming enclosure on St Helena Island (1916) records a time when Queensland communities were first seeking to manage the recreational demands of swimmers in the context of a growing public fear of sharks.
Article
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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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Despite the low chance of a person being bitten by a shark, there are serious associated costs. Electronic deterrents are currently the only types of personal deterrent with empirical evidence of a substantial reduction in the probability of being bitten by a shark. We aimed to predict the number of people who could potentially avoid being bitten by sharks in Australia if they wear personal electronic deterrents. We used the Australian Shark Attack File from 1900 to 2020 to develop sinusoidal time-series models of per capita incidents, and then stochastically projected these to 2066. We predicted that up to 1063 people (range: 185–2118) could potentially avoid being bitten across Australia by 2066 if all people used the devices. Avoiding death and injury of people over the next half-century is of course highly desirable, especially when considering the additional costs associated with the loss of recreational, commercial and tourism revenue potentially in the tens to hundreds of millions of dollars following clusters of shark-bite events.
Article
Over the last decade, an increase in the annual rate of shark bites on people has stimulated the development of new techniques aimed at reducing their occurrence, while minimising negative impacts to marine wildlife. One such technique is the SMART (Shark-Management-Alert-in-Real-Time) drumline, which allows for the capture and relocation of white sharks (Carcharodon carcharias), bull sharks (Carcharhinus leucas), and tiger sharks (Galeocerdo cuvier), the species responsible for most of the fatal shark bites on people. Over a 12-month period, we assessed the marine faunal assemblages observed in >1200 deployments of high-definition video cameras beneath SMART drumlines. Shark behaviours around SMART drumlines were also quantified. The faunal assemblage around the SMART drumlines was characterised by low richness, dominated by schooling bait fish, and influenced by sea surface temperature. Few non-target species of conservation concern (e.g. sea turtles, hammerhead sharks, or critically endangered greynurse sharks) were observed. Of the sharks approaching the drumlines, white sharks were more likely to bite and subsequently remove bait, leading to more instances of successful capture and release, and a greater rate of depredation. However, instances of depredation during the program were low and only occurred in 13 % of all shark bite interactions. Our results provide support for the use of SMART drumlines as an efficient tool for catching target shark species with minimal impact on non-target fauna.
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White (Carcharodon carcharias L.), bull (Carcharhinus leucas, Müller & Henle) and tiger (Galeocerdo cuvier, Péron & Lesueur) sharks are the primary species responsible for unprovoked shark bites. Historically, management practices were based on culling “target” shark species (i.e. white, bull and tiger sharks), which resulted in high levels of bycatch and mortality. Shark‐Management‐Alert‐in‐Real‐Time (SMART) drumlines were trialled in New South Wales, Australia, aiming to optimise the capture of target shark species while minimising bycatch and mortality. Target shark species accounted for 70% of the total catch, with white sharks contributing 298 of the 350 sharks that were caught. Four animals died, and bycatch consisted of 13 species including two threatened species. Generalised linear mixed models (GLMMs) revealed a significant spatial, temporal, environmental and gear influence on white shark catch rates. SMART drumlines are a useful tool for catching target shark species with low bycatch and mortality relative to historical bather protection methods.
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The disposal of whale carcasses in beach burials has raised perceptions of shark attraction to the adjacent water. Understanding the concerns and perceptions of the community is key to creating sound management practices and educational resources. We surveyed community perception of the disposal of whale carcasses and the factors influencing public opinion. Overall, the community underestimated carcass disposal costs, and considered nonviable methods (oceanic tow and carcass recycling) as their preferred options. Responses were divided into two groups: (1) those previously aware of this management issue, and (2) those unaware. The ‘aware’ group had polarised opinions with strong opinions about the safety of beach burial and its influence on shark attraction. The source of information for respondents drove perceptions with personal opinion being the highest, followed by media, perceived natural processes, and research in the aware group. Expert opinion, and common management practice were the lowest ranked information sources suggesting a lack of access to reliable information, or a disconnect between experts and the external community. Surprisingly, 27.8% of respondents would not change their opinion based on research, emphasising the complexity of the issue and of the relationship between managers and the public. This information will assist managers in the creation of comprehensive management practices, educational resources, communication of facts, and reduction of misconceptions around the disposal of whale carcasses.
Preprint
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DNA evidence is routinely used to identify individual predators responsible for attacks on people and livestock in terrestrial settings. However, the use of transfer DNA techniques in aquatic environments for similar purposes is a recent development. To date, DNA barcoding has been used successfully to identify shark species depredating fish catches and biting surfboards and neoprene surfaces. In this study we demonstrate the successful DNA barcoding and fingerprinting of individual sharks from transfer DNA collected directly from the wounds of two shark bite victims. The successful use of DNA techniques to identify both species and specific individuals responsible for shark bites opens the door to selective removal of these individuals as an innovative shark bite risk management strategy. This selective approach would be a more effective, eco-responsible, cost-effective and ethical solution for vulnerable taxa than ongoing non-selective culling campaigns.
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Interest in the direct interactions between individual people and nature has grown rapidly. This attention encompasses multiple academic disciplines and practical perspectives. A central challenge thus lies in creating a rich cross-disciplinary understanding of these interactions, rather than one that might become characterized by little conceptual, terminological and methodological unity. Here, to facilitate the former outcome, we bring together concepts and theories about direct human–nature interactions drawn from diverse disciplines within a unified conceptual framework. Using this framework, we discuss the linkages among key concepts and theories, identify important knowledge gaps and suggest directions for future research.
Technical Report
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Following several shark bite incidents in the Whitsundays from 2018 to 2019, the Queensland Government commissioned research to understand the abundance, distribution and movement of sharks in the Whitsundays. In conjunction with this research, Fisheries Queensland commissioned Reef Ecologic to work with key stakeholders in the Whitsundays to investigate how water users such as boaters, fishers, swimmers and divers could reduce their risk of a shark bite by altering their own behaviours. The project began in November 2019 and was completed in January 2021. The project commenced with a series of stakeholder workshops, bringing together tourism operators, fishers, divers and other Whitsundays community members with marine managers and shark researchers to explore potential risk factors and co-design possible solutions. Following a pause due to the COVID-19 pandemic, the project resumed in September 2020 with the Reef Ecologic team working with selected bareboat sailing charter operators as the test group for the project. The objectives of the project were to: 1) identify human behaviours that could be contributing to increased risk of shark bites, 2) identify ways to alter these behaviours to reduce risk of shark bites, 3) pilot trial a behavioural intervention for at least one key stakeholder group targeting at least one priority behaviour. Building on the Queensland Government’s SharkSmart guidelines a behavioural change intervention research study was designed with the aim of influencing fishing, swimming and waste disposal behaviours of tourists. The following eight desired SharkSmart behaviours were investigated with bareboat tourists in the Whitsundays region. In-water swimming/snorkelling behaviours • Avoid swimming near (within 200 m) people who are fishing. • Avoid swimming in murky water. • Avoid swimming alone. • Avoid swimming near baitfish or schooling birds. • Avoid swimming in busy anchorages. • Avoid swimming at dawn or dusk. Boating and fishing behaviours • Avoid fishing near (within 200 m) people who are swimming. • Avoid throwing fish frames/fish scraps into the water. A before, after, control, impact (BACI) scientific study design was used to test the effectiveness of interventions. Surveys were conducted before and after intervention to measure changes in knowledge and behaviour. Between September and December 2020, behavioural interventions were delivered for two tourism companies. A third company was used as a control and did not receive any intervention. A total of 229 tourists were surveyed upon return of their trip. The main water-based activities undertaken by guests were swimming/snorkelling (91.3%) and fishing (68.2%). The majority of tourists (98.3%) were from Australia with 86% from Qld. Tourist knowledge of shark safety behaviours was very high (93-100%), but knowledge was not a strong predictor of behaviour. Approximately 3 out of 10 people ignored one or more of the voluntary SharkSmart guidelines and participated in risky behaviours including swimming alone, swimming with baitfish, swimming in murky water, not following signage and disposing of food or fish scraps in the water. The knowledge-behaviour inequality was particularly evident when it came to several in-water and waste disposal behaviours. Despite very high knowledge of the importance of keeping fish waste and food scraps out of the water where people swim (100% of respondents claimed to be aware of this behaviour both before and after the intervention), around 30% of people reported throwing food waste or fish waste into the sea. Six recommendations are provided with the aim of improving research and encouraging behaviour change to reduce the risk of shark bites in the Whitsundays region. Comprehensive recommendations are in Chapter 10 and an abbreviated summary of the recommendations is: I. Expand shark safety interventions to other tourism operators in Whitsundays. II. Expand shark safety interventions to include recreational and commercial fishers III. Management agencies influence behavioural change through mechanisms such as. special management zones, regulation, or penalties. IV. The Australian Shark Attack File include additional data that support behavioural change interventions. V. A higher level of caution is applied in the Whitsunday region between September and December due to increased shark risk VI. In future studies, include surveys of fishing catch and barriers to keeping food and rubbish onboard
Article
Biodiversity is vital to the welfare and survival of humans, but public support for conservation of most animal species is appallingly limited. Vertebrates make up less than 5% of the world’s documented animal species, but are viewed far more sympathetically than invertebrates. This is because humans are empathetic with the appearance and behaviour of many of them, particularly the charismatic superstars like pandas and tigers that currently are the mainstays of biodiversity fundraising. Conversely, just as such attractive icons are effective ambassadors of biodiversity conservation, so certain detested and sometimes dangerous vertebrate pests have greatly compromised the public image of biodiversity. Some of these species, admittedly, are responsible for significant damage to health and economic welfare. Nevertheless, this paper shows that all play important ecological roles, they have compensating economic values, their harm has often been exaggerated, and their very negative public images are undeserved. This first installment deals with the most reviled ‘lower’ vertebrate species: sharks (representing fish); frogs and toads (representing amphibians); snakes (representing reptiles); and vultures (representing birds). The next contribution will deal with mammals.
Preprint
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DNA evidence is routinely used to identify individual predators responsible for attacks on people and livestock in terrestrial settings. However, the use of transfer DNA techniques in aquatic environments20 for similar purposes is a recent development. To date, DNA barcoding has been used successfully to identify shark species depredating fish catches and biting surfboards and neoprene surfaces. In this study we demonstrate the successful DNA barcoding and fingerprinting of individual sharks from transfer DNA collected directly from the wounds of two shark bite victims. The successful use of DNA techniques to identify both species and specific individuals responsible for shark bites opens the door to selective removal of these individuals as an innovative shark bite risk management strategy. This selective approach would be a more effective, eco-responsible, cost-effective and ethical solution for vulnerable taxa than ongoing non-selective culling campaigns.
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Climate change is intensifying conflicts between people and wildlife
Chapter
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AUGUST 2006 White shark conservation and recreational safety in the inshore waters of Cape Town, South Africa P r o c e e d i n g s A u g u s t 2 0 0 6 Foreword The contents of these proceedings are the result of over a year's foresight and planning by the City of Cape Town, the Department of Environmental Affairs and Tourism (DEAT) and the World Wide Fund for Nature (WWF) South Africa. Following a number of shark attacks between 2001 and 2004, the City of Cape Town recognized that a proactive approach to addressing white shark management and recreational safety was needed. Central to this challenge was not only the apparent paradox between the objectives of recreational safety and white shark conservation, but also the lack of clarity about the roles and responsibilities of different government departments. In June 2005, the City and its key partners, DEAT and WWF, started a process to assess the full range of possible causes and potential management responses so as to accurately inform the decision making process. WWF was approached to assist in facilitating a workshop of specialists in the fields of white shark conservation and recreational safety. A number of recognised experts were invited to contribute written papers on a broad range of topics. The workshop, held on 29 & 30 May 2006 in Cape Town, was characterized by very constructive debate and was successful in adopting a number of key conclusions and recommendations based on the information presented. Whilst these recommendations do not carry any legislative weight, they do constitute the collective opinion of the most highly regarded experts in these fields in South Africa and are backed up by fifteen scientific and background papers that were submitted to the workshop and reviewed by the editors. These recommendations have played a central role in informing the City's Draft White Shark and Coastal Recreational Safety Policy and Strategy.
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Refugia play an important role in shaping predator/prey interactions; however, few studies have investigated predator–prey relationships between large marine vertebrates, mainly due to the logistical challenges of studying marine species. The predictable interactions between Cape fur seals and white sharks in South Africa at two neighbouring seal colonies (Seal Island and Geyser Rock) with similar breeding conditions, but distinct adjacent seascapes, offer an opportunity to address this gap. Geyser Rock differs from Seal Island in being surrounded by abundant refugia in the form of kelp beds and shallow reefs, while Seal Island is mostly surrounded by deep open water. In this study, we compare data collected from Geyser Rock to the published data at Seal Island and ask, do seals adjust their anti-predator tactics as a function of landscape features? We found that during periods of high white shark presence, seals at Geyser Rock reduced their presence in open-water and utilized areas that contained complex landscapes around the colony. Although seals at Geyser Rock formed groups when traversing open water, neither group size (high risk median = 4, low risk median = 5) nor temporal movement patterns varied significantly with white shark presence as has been shown at Seal Island. Furthermore, recorded hourly predation rates at Seal Island were 12.5 times higher than at Geyser Rock. Together, these findings suggest that refuge use may be the more effective anti-predator response of seals to a seasonally abundant predator and that the predations at Seal Island reflect a comparative lack of refugia.
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A between-subjects experiment (N = 531) studied the juxtaposition of programming from the Discovery Channel’s Shark Week with shark conservation public service announcements (PSAs). Cultivation and priming theories provided a conceptual framework for testing how shark-on-human violence paired with different types of PSAs (celebrity endorser present or not) influence audiences’ emotional reactions, threat perceptions, willingness to support conservation, and intentions to seek information. Findings reveal that shark-on-human violence and presence of a PSA influence fear reactions and perceived threat of shark attacks. Findings related to conservation support, information seeking, and the role of previous Shark Week viewing and demographics are also discussed.
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Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential. Furthermore, we identify needs for further research and scope for improvement in this kind of scenario-based exposure analysis.
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Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195-283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n = 16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean = 533 km) with eight of these sharks returning to the study site. During migration, individuals exhibited rates of movement between 2 and 59 km.d-1 (mean = 17.58 km.d-1) and were recorded travelling annual distances of between 450 and 3760 km (mean = 1163 km). Migration towards lower latitudes primarily took place in austral spring and winter and there was a significant negative correlation between residency and mean monthly sea temperature at the study site. This suggested that seasonal change is the primary driver behind migration events but further investigation is required to assess how foraging and reproductive activity may influence residency patterns and migration. Results from this study highlight the need for further understanding of bull shark migration dynamics and suggest that effective conservation strategies for this vulnerable species necessitate the incorporation of congruent trans-boundary policies over large spatial scales.
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Partial migration is considered ubiquitous among vertebrates, but little is known about the movements of oceanodromous apex predators such as sharks, particularly at their range extents. PAT-Mk10 and SPOT5 electronic tags were used to investigate tiger shark (Galeocerdo cuvier) spatial dynamics, site fidelity and habitat use off eastern Australia between April 2007 and May 2013. Of the 18 tags deployed, 15 recorded information on depth and/or temperature, and horizontal movements. Tracking times ranged between four and 408 days, with two recovered pop-up archival tags allowing 63 days of high-resolution archived data to be analysed. Overall mean proportions of time-at-depth revealed that G. cuvier spent the majority of time-at-depths of <20 m, but undertook dives as deep as 920 m. Tagged sharks occupied ambient water temperatures from 29.5 °C at the surface to 5.9 °C at depth. Deep dives (>500 m) occurred mostly around dawn and dusk, but no definitive daily dive patterns were observed. Horizontal movements were characterised by combinations of resident and transient behaviour that coincided with seasonal changes in water temperature. While the majority of movement activity was focused around continental slope waters, large-scale migration was evident with one individual moving from offshore Sydney, Australia, to New Caledonia (c. 1,800 km) in 48 days. Periods of tiger shark residency outside of Australia’s fisheries management zones highlight the potential vulnerability of the species to unregulated fisheries and the importance of cross-jurisdictional arrangements for species’ management and conservation.
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An unprovoked shark bite is an extremely infrequent, but highly disturbing hazard for water sport participants in many parts of the world. Information was analysed on the total number of unprovoked shark bites between 1982 and 2011. In this period, unprovoked shark bite were recorded from 56 countries with 27 recording fatalities; however 84.5% occurred in only six countries - United States, Australia, South Africa, Brazil, Bahamas and Reunion Island. The three shark species commonly responsible for unprovoked bites are the white shark (Carcharodon carcharias), the tiger shark (Galeocerdo cuvier), and the bull shark (Carcharhinus leucas). Over the period examined, the total number of unprovoked shark bites and the number that were fatal increased in frequency. However, fatalities from unprovoked fatal shark bite still represented an infrequent hazard to people utilising the coastal zone for water-based leisure activities. The increase in unprovoked shark bite could not be explained entirely by increases in human population, and this article also concluded that changes in the population of relevant shark species were also unlikely to explain the increase. The paper concluded that both natural and anthropogenic factors may change the amount of spatial overlap between relevant shark species and areas of human use.
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Large sharks are top predators in most coastal and marine ecosystems throughout the world, and evidence of their reduced prominence in marine ecosystems has been a serious concern for fisheries and ecosystem management. Unfortunately, quantitative data to document the extent, timing, and consequences of changes in shark populations are scarce, thwarting examination of long-term (decadal, century) trends, and reconstructions based on incomplete data sets have been the subject of debate. Absence of quantitative descriptors of past ecological conditions is a generic problem facing many fields of science but is particularly troublesome for fisheries scientists who must develop specific targets for restoration. We were able to use quantitative measurements of shark sizes collected annually and independently of any scientific survey by thousands of recreational fishermen over the last century to document decreases in the size of large sharks from the northern Gulf of Mexico. Based on records from fishing rodeos in three U.S. coastal states, the size (weight or length) of large sharks captured by fishermen decreased by 50-70% during the 20years after the 1980s. The pattern is largely driven by reductions in the occurrence and sizes of Tiger Sharks Galeocerdo cuvier and Bull Sharks Carcharhinus leucas and to a lesser extent Hammerheads Sphyrna spp. This decrease occurred despite increasing fishing effort and advances in technology, but it is coincident with the capitalization of the U.S. commercial shark long-line fishery in the GOM.
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Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.
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White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central California" at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a limited number of sites and that account for all life history stages across the species' range of habitats.
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White sharks are highly migratory apex predators, globally distributed in temperate, sub-tropical, and tropical waters. Knowledge of white shark biology and ecology has increased recently based on research at known aggregation sites in the Indian, Atlantic, and Northeast Pacific Oceans; however, few data are available for the Northwest Pacific Ocean. This study provides a meta-analysis of 240 observations of white sharks from the Northwest Pacific Ocean between 1951 and 2012. Records comprise reports of bycatch in commercial fisheries, media accounts, personal communications, and documentation of shark-human interactions from Russia (n = 8), Republic of Korea (22), Japan (129), China (32), Taiwan (45), Philippines (1) and Vietnam (3). Observations occurred in all months, excluding October-January in the north (Russia and Republic of Korea) and July-August in the south (China, Taiwan, Philippines, and Vietnam). Population trend analysis indicated that the relative abundance of white sharks in the region has remained relatively stable, but parameterization of a 75% increase in observer effort found evidence of a minor decline since 2002. Reliably measured sharks ranged from 126-602 cm total length (TL) and 16-2530 kg total weight. The largest shark in this study (602 cm TL) represents the largest measured shark on record worldwide. For all countries combined the sex ratio was non-significantly biased towards females (1∶1.1; n = 113). Of 60 females examined, 11 were confirmed pregnant ranging from the beginning stages of pregnancy (egg cases) to near term (140 cm TL embryos). On average, 6.0±2.2 embryos were found per litter (maximum of 10) and gestation period was estimated to be 20 months. These observations confirm that white sharks are present in the Northwest Pacific Ocean year-round. While acknowledging the difficulties of studying little known populations of a naturally low abundance species, these results highlight the need for dedicated research to inform regional conservation and management planning.
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Human–wildlife conflict (HWC) is a significant and growing problem, with mitigation measures being increasingly dependent on sociopolitical landscapes. We surveyed 766 people from two Australian states to assess their understanding of shark attack mitigation measures. Although beach users were relatively aware of existing mitigation measures, the efficacy of aerial patrol was overestimated, as was the risk of shark attack. The latter, as well as the innate fear of shark attacks, is likely to explain the high level of worry related with shark attack and fits within the affect heuristic that can influence how people respond to risk situations. Beach users did not, however, choose beaches based on existing mitigation measures. Results highlight the need for improved education about the risks of shark attack and for further research into the emotional response from low probability–high consequences incidents.
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We show that the distributions of both exploited and nonexploited North Sea fishes have responded markedly to recent increases in sea temperature, with nearly two-thirds of species shifting in mean latitude or depth or both over 25 years. For species with northerly or southerly range margins in the North Sea, half have shown boundary shifts with warming, and all but one shifted northward. Species with shifting distributions have faster life cycles and smaller body sizes than nonshifting species. Further temperature rises are likely to have profound impacts on commercial fisheries through continued shifts in distribution and alterations in community interactions.
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Abstract Five hundred and ninety-nine primary producers and consumers in the Papaha¯naumokua¯kea Marine National Monument (PMNM) (22�N–30�N, 160�W– 180�W) were sampled for carbon and nitrogen stable isotope composition to elucidate trophic relationships in a relatively unimpacted, apex predator–dominated coral reef ecosystem. A one-isotope (d13C), two-source (phytoplankton and benthic primary production) mixing model provided evidence for an average minimum benthic primary production contribution of 65 % to consumer production. Primary producer d15N values ranged from -1.6 to 8.0 % with an average (2.1 %) consistent with a prevalence of N2 fixation. Consumer group d15N means ranged from 6.6 % (herbivore) to 12.1 % (Galeocerdo cuvier), and differences between consumer group d15N values suggest an average trophic enrichment factor of 1.8 % D15N. Based on relative d15N values, the larger G. cuvier may feed at a trophic position above other apex predators. The results provide baseline data for investigating the trophic ecology of healthy coral reef ecosystems.
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Previous work on white sharks indicate the species show seasonally limited movement patters, at certain aggregation sites small areas may play vital roles in the life history of a large amount of the population. Acoustic telemetry was used to estimate habitat use of white sharks, Carcharodon carcharias, while aggregating at Mossel Bay, South Africa. Total range of all shark tracks combined accumulated 782 h and covered an area of 93.5 km2 however, within this range, sharks were found to highly utilise a core habitat (50 % Kernel, K50) of just 1.05 km2 over a reef system adjacent to a river mouth. Individual tracks revealed additional core habitats, some of which were previously undocumented and one adjacent to a commercial harbor. Much was found to be dependent on the size of the shark, with larger sharks (>400 cm) occupying smaller activity areas than subadult (300–399 cm) and juvenile (<300 cm) conspecifics, while Index of Reuse (IOR) and Index of Shared Space (IOSS) were both found to increase with shark size. Such results provide evidence that larger white sharks are more selective in habitat use, which indicates they have greater experience within aggregation sites. Furthermore, the focused nature of foraging means spatially restricted management strategies would offer a powerful tool to aid enforcement of current protective legislation for the white shark in similar environments of limited resources and capacity.
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An abnormally high shark attack rate verified off Recife could be related to migratory behavior of tiger sharks. This situation started after the construction of the Suape port to the south of Recife. A previous study suggested that attacking sharks could be following northward currents and that they were being attracted shoreward by approaching vessels. In this scenario, such northward movement pattern could imply a higher probability of sharks accessing the littoral area of Recife after leaving Suape. Pop-up satellite archival tags were deployed on five tiger sharks caught off Recife to assess their movement patterns off northeastern Brazil. All tags transmitted from northward latitudes after 7-74 days of freedom. The shorter, soak distance between deployment and pop-up locations ranged between 33-209 km and implied minimum average speeds of 0.02-0.98 km.h−1. Both pop-up locations and depth data suggest that tiger shark movements were conducted mostly over the continental shelf. The smaller sharks moved to deeper waters within 24 hours after releasing, but they assumed a shallower (< 50 m) vertical distribution for most of the monitoring period. While presenting the first data on tiger shark movements in the South Atlantic, this study also adds new information for the reasoning of the high shark attack rate verified in this region.
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Shark attacks on humans are high profile events which can significantly influence policies related to the coastal zone. A shark warning system in South Africa, Shark Spotters, recorded 378 white shark (Carcharodon carcharias) sightings at two popular beaches, Fish Hoek and Muizenberg, during 3690 six-hour long spotting shifts, during the months September to May 2006 to 2011. The probabilities of shark sightings were related to environmental variables using Binomial Generalized Additive Mixed Models (GAMMs). Sea surface temperature was significant, with the probability of shark sightings increasing rapidly as SST exceeded 14°C and approached a maximum at 18°C, whereafter it remains high. An 8 times (Muizenberg) and 5 times (Fish Hoek) greater likelihood of sighting a shark was predicted at 18°C than at 14°C. Lunar phase was also significant with a prediction of 1.5 times (Muizenberg) and 4 times (Fish Hoek) greater likelihood of a shark sighting at new moon than at full moon. At Fish Hoek, the probability of sighting a shark was 1.6 times higher during the afternoon shift compared to the morning shift, but no diel effect was found at Muizenberg. A significant increase in the number of shark sightings was identified over the last three years, highlighting the need for ongoing research into shark attack mitigation. These patterns will be incorporated into shark awareness and bather safety campaigns in Cape Town.
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South Africa is reputed to host the world’s largest remaining population of white sharks, yet no studies have accurately determined a population estimate based on mark-recapture of live individuals. We used dorsal fin photographs (fin IDs) to identify white sharks in Gansbaai, South Africa, from January 2007 – December 2011. We used the computer programme DARWIN to catalogue and match fin IDs of individuals; this is the first study to successfully use the software for white shark identification. The programme performed well despite a number of individual fins showing drastic changes in dorsal fin shape over time. Of 1682 fin IDs used, 532 unique individuals were identified. We estimated population size using the openpopulation POPAN parameterisation in Program MARK, which estimated the superpopulation size at 908 (95% confidence interval 808–1008). This estimated population size is considerably larger than those described at other aggregation areas of the species and is comparable to a previous South African population estimate conducted 16 years prior. Our assessment suggests the species has not made a marked recovery since being nationally protected in 1991. As such, additional international protection may prove vital for the long-term conservation of this threatened species.<br/
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Shark attacks have historically been studied from a viewpoint of encounter number per region and so limited to the areas in which the attacks occurred. In this exploratory modeling study, the goal was to examine whether an area-specific cluster analysis algorithm undertaken with a modern cluster analysis tool (SaTScan™ 9.1.0) could enhance our spatial and spatio-temporal understanding of attack patterns. The data used were from Florida's east coast between 1994 and 2009. The program suggests several high- and low-risk areas for shark attacks. The results are discussed from a quantitative rather than qualitative perspective.
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