Context White sharks (Carcharodon carcharias) globally display seasonal site fidelity to coastal aggregations across their range, yet the prolonged absences from these aggregations have often been linked to the presence and predation by killer whales (Orcinus orca). This was the case following a predation event in 2015 at the Neptune Islands, when white sharks became abnormally absent for more than 2 months. However, how much this prolonged absence at the Neptune Islands was influenced by the predation event is unknown.Aims Our study assessed whether the 69-day white shark absence in early 2015 was due to a predation event by killer whale in February 2015, or if such extended absence can reflect natural variations in residency at aggregations.Methods We analysed 12 years (2013-2024) of white shark sighting records from wildlife tourism operators and acoustic telemetry data to investigate patterns of shark presence before and after the 2015 killer whale predation event, a shark mortality, and a killer whale sighting.Key results White sharks exhibited six prolonged absences (mean absence duration + 3 standard deviations) across the 12-year study period, with the longest absence being 92 days, which was longer than the absence recorded in 2015 following killer whale predation (69 days). The number and extent of prolonged absences suggest that these departures are not unique to the 2015 event and may instead reflect natural or random variation in residency.Conclusions Our findings showed that although killer whale predation and presence can trigger immediate responses and departure from aggregation sites, they are unlikely to be the sole driver of prolonged white shark absences at the Neptune Islands.Implications Prolonged absences of white sharks may be influenced by killer whale predation as well as other predator-prey interactions and environmental factors. Integrative, long-term monitoring of all prey and predators is critical for understanding site fidelity and absence behaviour of white sharks.

Wildlife tourism often uses food-based attractants to aggregate focal species. While this can adversely affect the focal species, there is limited understanding of its effects on non-focal species which often also respond to the attractant. At the Neptune Islands, South Australia, bait and berley are used to entice white sharks Carcharodon carcharias to cage-diving vessels, inadvertently attracting and feeding silver trevally Pseudocaranx georgianus. Feeding on the bait and berley affects their diet, but it is unknown whether it also affects their movements, behaviour, and energy budgets. We used a fine-scale acoustic telemetry array to monitor the movement and activity (i.e. proxy for energy expenditure calculated from 3-dimensional acceleration) of 25 tagged silver trevally in response to white shark tourism. The presence of cage-diving operators increased residency across weekly (+32%) and daily (+20%) scales, while reducing the core space by aggregating them at the surface (<5 m), close to food-based operators. Despite observations of silver trevally bursting towards tethered baits, changes in activity (acceleration, m s-1) were minimal compared to non-operator days. While food was available nearly daily, a thermally triggered seasonal exodus by 76% of individuals indicates that silver trevally still move and behave naturally. However, the supplemental nutrients and substantial time spent at Neptune Islands has the potential to alter the energy budgets of silver trevally. Our findings reveal the impacts that provisioning from wildlife tourism can have on non-focal schooling pelagic fish, supporting the need for management of wildlife tourism to account for the whole ecosystem when assessing the ecological sustainability of a tourism industry.

The high dispersal ability, strong population connectivity, and broad geographic ranges of many exploited marine species present significant challenges for identification, assessment and management of stocks that straddle jurisdictions. Multi-disciplinary approaches are increasingly used to provide a more comprehensive understanding of biological stock structure. Here, we used analyses of population genomics and otolith shape and chemistry to clarify the population structure and connectivity of the socially and economically important silver trevally (Pseudocaranx georgianus). Muscle and fin-clipped tissues (n = 835) and otoliths (n = 940) were sampled from 32 locations across five jurisdictions around Australia. The genomic analysis also included three locations in Aotearoa New Zealand to provide broader spatial context for interpreting biological stock structure. Our results identified three populations, or biological stocks, encompassing extensive distances along coastlines and across jurisdictions. Based on the boundaries between populations, we suggest two stocks to be defined for Australia-a 'western' stock spanning Western Australia, South Australia and western Victoria, and an 'eastern' stock spanning eastern Victoria, New South Wales and northern Tasmania, and one biological stock for New Zealand. The boundary between Australian stocks appears to have originated from the historical barrier of the Bassian Isthmus, with contemporary oceanographic processes likely maintaining the separation of the two broad populations and promoting high connectivity within each population. Our findings suggest that current management units may not adequately represent the true biological stock structure of the species. Cross-jurisdictional collaboration is recommended to clarify rates of recruitment within and among jurisdictions and to revise the current assessment framework to ensure effective fisheries management can be achieved for silver trevally in Australia.

Animal-borne cameras are effective tools to study the fine-scale behavior and habitat use of a wide range of marine taxa, including birds, mammals, sea turtles, and elasmobranchs. We deployed animal-borne camera and accelerometer packages on 13 juvenile white sharks (Carcharodon carcharias; 174–283 cm total length) along the coast of New South Wales (Australia) to investigate white shark foraging behavior and habitat preferences. We annotated and assigned every second of footage to specific behaviors (e.g., swimming direction, foraging behavior) and environmental variables (e.g., habitat type) and recorded interactions with other species. From the 68.5 h of footage obtained, we identified 20 burst events (0.1% of the total time), but a potential prey was visible in only three of these instances (15% of burst events). Moreover, 10 of these burst events (50%) were along the seafloor without substantial changes in shark depth, potentially linked to benthic foraging behavior. White sharks mostly occupied sandy, low-complex habitats, which could be driven by prey availability, e.g., benthic elasmobranchs, or the ease of navigation compared to more complex environments. Our findings provide new insights into the foraging ecology and habitat use of juvenile white sharks and document novel interspecific interactions, highlighting the utility of animal-borne cameras in capturing behaviors that are otherwise difficult to observe.

Abstract Effective research and monitoring requires accurate, interoperable and representative data. Stereo‐video based methods are commonly used to survey fish and are rapidly expanding globally due to their cost‐effectiveness, ability to provide accurate body size measurements, non‐destructive approach and capacity to create permanent data records. However, the representativeness of both stereo and mono‐video derived data depends on standardised approaches to provide quality assurance of reliable, reproducible and error‐free data. A national synthesis of both stereo and mono‐video fish survey datasets identified numerous errors in data collection and annotation, many of which are also relevant to other survey methods. To develop an open‐source toolkit, CheckEM, for quality control checks on fish survey data. The CheckEM web application and R package identifies errors in metadata and cross‐checks annotations of fish with taxonomic databases, expected spatial distributions, and, in the case of stereo‐video, maximum body sizes, and works with the outputs of a range of annotation tools (including EventMeasure and other annotation software). CheckEM flags species observed beyond their known range, outdated scientific names and body size outliers. CheckEM standardises, cleans and visualises datasets, offering interactive plots and tables in a user‐friendly interface. Downloadable summary data and error reports support iterative checks and improvement of data quality. We demonstrate that CheckEM enhances data accuracy, confidence, interoperability and reusability, improving collaboration and cross‐dataset comparisons to support robust analyses and informed marine monitoring and management.

The reduction and cessation of human activities due to the COVID-19 pandemic impacted animal populations globally, often with ecological and economic repercussions on sectors such as wildlife tourism. Restrictions in human mobility led Australia's only white shark (Carcharodon carcharias) cage-diving industry in South Australia to stop for 50 days between March and May 2020 - the longest period of industry inactivity for over 12 years. More than 10 years of monitoring and research on the sustainability of the industry was leveraged to investigate the immediate and long-term impacts of this 50-day closure on white sharks and the supporting ecosystem using a before, during, and after design based on ecological and economic metrics. We found limited impacts on the residency, activity, and diet of white sharks but a 10-fold reduction in the economic value of the industry in April - May 2020. Only silver trevally (Pseudocaranx georgianus), a species that commonly associates with cage-diving activities, showed behavioural modification, shifting its diet from provisioned to natural sources of food and reducing its residency at operator sites; however, these changes were short-term and reverted once operations resumed. Overall, there was no evidence of lasting impacts of COVID-19 restrictions on white sharks or other fish that closely associate with cage-diving activities. The prompt resumption of tourism and continued implementation of and adherence to management regulations that restrict the amount of bait/berley and operational capacity likely moderated any behavioural changes of white sharks both during and after COVID-19.

Identification of habitat of pelagic species is key to determining the drivers of distribution, and possible limitations on suitable habitats. Yellowtail Kingfish (Seriola lalandi) are a large, pelagic species of high recreational and commercial value, yet considerable knowledge gaps exist for their horizontal, vertical, and thermal habitat preferences. We used satellite telemetry to quantify the use of continental shelf (on-shelf) and offshore (off-shelf) habitats by kingfish off south-eastern Australia and New Zealand. Fifty adult kingfish were tracked for 3159 days (median +/- sd. = 34 +/- 81.8), travelling up to 4101 km (351 +/- 790). Kingfish exhibited connectivity between waters on and off continental shelf, with 1832 days in off-shelf waters. Vertical distributions were largely restricted to the upper 100 m, but kingfish tagged near offshore islands tended to inhabit deeper waters. Multiple kingfish dove beyond 200 m (n = 6), including a maximum depth of 475 m. Thermal habitats were highly variable, spanning 16 degrees C (11.0-27.0 degrees C), albeit an affinity for 17.4-20.8 degrees C. The diversity of movements, including offshore and cross-jurisdictional, highlight the complexities of kingfish behaviour and population dynamics which should be considered by fisheries management.

1.The development and scientific testing of shark-bite mitigation measures are increasing, but unstandardised testing impedes our ability to compare their efficacy.2.We did a systematic review and meta-analysis to summarise efficacy using qualitative and quantitative approaches.3.We reviewed 67 papers testing 114 measures across three mitigation types (area/personal/injury reduction). Measures to protect areas were the most tested (n = 64), followed by personal deterrents (n = 29). Effectiveness (based on vote-counting analysis) and mean Hedges’ g were similar across mitigation types, but personal measures, especially electric deterrents, had the highest variation and magnitude of effect sizes. Personal deterrent studies were all manipulative and provided the ability to test reduction in simulated bites, whereas area protection studies were often mensurative (70 %) and mostly measured shark abundance.4.We recommend that future studies use the highest inference type as is reasonably practical (i.e., reduction in actual or simulated shark bites rather than differences in shark abundance). As the number of shark bites and the period over which mitigation measures have been implemented increase, so will opportunities to test the effectiveness of area protection quantitatively using high-inference metrics.5.Our findings should encourage discussions among policy makers, water users, and conservationists to test measures with robust, quantitative assessments to reduce shark-bite risk.

Research on elusive and endangered species presents considerable challenges, as it requires balancing minimal disturbance to individuals with the need to maximize data collection to address key ecological questions. For many of these species, major knowledge gaps persist, particularly regarding their movements, trophic ecology, and population structure—information essential for effective management and conservation. To collect the data required to address these gaps, we engineered a custom probe for deployment via a modified speargun, enabling simultaneous tagging and biopsy sampling of elasmobranchs in a single shot. We field-tested this new tool on the Critically Endangered Great hammerhead (Sphyrna mokarran) over three campaigns (February 2023-March 2023; December 2023-March 2024; December 2024-March 2025) in the atolls of Rangiroa and Tikehau (French Polynesia). The tool was iteratively refined, achieving an 83

Sensory information drives animal behaviour and thus understanding perception is integral to species conservation and management, including the mitigation of human-shark interactions. A recent study on white sharks (Carcharodon carcharias) showed that manipulating the visual cues of objects that resemble natural prey reduces the likelihood of sharks biting the objects, potentially offering new technology to reduce shark-bites. These experiments used artificial counterilluminated prey (seal-shaped decoys) towed behind a boat. However, white sharks also target static objects. Moreover, there is a risk that bright lights may be attractive to other potentially dangerous shark species. In this study, we evaluated the potential of counterillumination for shark-bite mitigation by comparing interactions of white and bull sharks (Carcharhinus leucas) with static counterilluminated decoys against non-counterilluminated control decoys. Lighting of different intensities arranged as horizontal stripes on the underside of oval-shaped decoys were tested. White sharks interacted less with counterilluminated decoys compared to control decoys, at the medium and high light intensities. However, they interacted more when the stripes were dimmest or the lights were on but covered. Whereas bull sharks were unaffected. Counterillumination technology shows promise for reducing human-shark encounters with white sharks when sufficiently bright, while posing minimal risk of attracting bull sharks.

Context Shark bites on humans are rare but can have substantial consequences for local coastal communities and businesses, often prompting pressure to implement effective mitigation measures. Wetsuits that incorporate bite-resistant materials have emerged as a new mitigation strategy that aims to reduce fatalities from shark bites, by reducing the severity of injuries inflicted from bites (e.g. lacerations, punctures, tissue and blood loss). Chainmail protective suits were developed in the 1970s, but lack the flexibility required for most aquatic activities (e.g. surfing, diving). More recently, lightweight puncture-resistant materials (e.g. Kevlar, ultra-high molecular weight polyethylene) have been incorporated into wetsuits, providing more flexibility for the user compared to chainmail suits, while reducing abrasions and cuts. However, despite the availability of bite-resistant wetsuits for commercial and public purchase, their ability to reduce injuries from large, predatory sharks (i.e. white shark, Carcharodon carcharias, and tiger shark, Galeocerdo cuvier) is unknown.Aims We tested the efficacy of four bite-resistant wetsuit materials (Aqua Armour, Shark Stop, ActionTX-S and Brewster material) to reduce damage incurred from white and tiger shark bites.Methods The ability to reduce injuries from shark bites was quantified by comparing the proportion of the bitten surface area across four damage categories of increasing severity (i.e. C1, superficial; C2, slight; C3, substantial; or C4, critical) between a control material (3-mm-thick neoprene) and the four bite-resistant materials.Key results All bite-resistant materials reduced the proportional area of bites in substantial and critical damage categories, the categories associated with haemorrhaging and major vascular injury. However, there were limited to no differences in substantial and critical damage categories across the bite-resistant materials. Shark length also influenced the proportion of damage from tiger shark bites, but not from white shark bites.Conclusions Although internal and crushing injuries might still occur, bite-resistant materials offer an improved level of protection that can reduce severe wounds and blood loss, and should be considered as part of the toolbox and measures available to reduce shark-bite risk and resulting injuries.Implications These findings will allow for informed decisions to be made about the use of bite-resistant wetsuit materials for ocean users.

Management of protected areas is as much about understanding how society values these resources as it is about understanding ecological processes. Yet, in comparison to standard ecosystem monitoring and economic evaluation, social values are frequently overlooked because of the challenge to measure and define them. As marine protected areas are currently the fastest growing protected area type, this article argues the need to incorporate social value assessment in planning and policy decisions to improve ecological and social outcomes. This study surveyed 675 white shark (Carcharodon carcharias) cage-dive participants to investigate how tourists' value the Neptune Islands group (Ron and Valerie Taylor) Marine Park. Applying a value typology previously used in forests, respondents were able to identify with 13 distinct values. Results demonstrate that tourists hold biocentric, indirect use, and nonconsumptive values of the marine park as most important. The relevance of these results as an indicator of tourists' preference for management decisions is discussed.

Satellite telemetry has revolutionized the study of aquatic animal movement by enabling high-resolution tracking across vast spatial and temporal scales. Here we undertake a global systematic review of studies since 1982 to summarise state of knowledge by taxonomic group, sample size, life history stage studied, and tracking mode (i.e., archival vs. near real-time). We then classify studies according to defined research and management themes, highlight geographic trends aligned with FAO major fishing areas, and examine how these themes are distributed globally. Of a total of 1137 studies, encompassing over 30 000 tagged individuals across diverse aquatic taxa, mammals, fish, and reptiles were the most studied. Research has largely focused on marine systems, particularly in the northern Atlantic and Pacific, but freshwater ecosystems remain underrepresented. Most studies explored general movement patterns, with fewer addressing applied conservation topics such as movement barriers or protected area effectiveness. Overall, integration with complementary methods (e.g., genetic or physiological sampling) was limited. Addressing identified gaps in underrepresented taxa (e.g., invertebrates), regions (e.g., the Indian Ocean), and emerging topics (e.g., climate change responses) will be critical to fully realize the potential of satellite telemetry for conservation and management of aquatic biodiversity.

Sharks often modify their behaviour to obtain food from humans. Food provisioning can lead to behavioural conditioning, which can alter resource use patterns and interactions within and between species. We used acoustic telemetry and dietary biomarkers (fatty acids and stable isotopes) to quantify dusky (Carcharhinus obscurus; n = 18) and Galapagos (C. galapagensis; n = 16) shark associations with fishing piers at Norfolk Island, Australia between 2021 and 2024. Individuals visited the piers, on average, once every four days (~ 3 h daily), with dusky sharks usually arriving in the early afternoon and staying until dusk while Galapagos sharks arrived at dusk and left in the early morning. Despite this temporal partitioning, the diets of both species were indistinguishable from each other and showed only limited contribution of discarded fish; however, fish scraps were more common in the diet of sharks with high residency to the piers. These findings indicate that although incidental feeding contributes to the presence of sharks at the piers, it has likely not markedly altered natural foraging behaviour with regular visits to the piers only conducted intermittently by a subset of the tagged population to supplement diet. Understanding how sharks use the piers in response to human activities will help assess current waste disposal practices at Norfolk Island and ongoing monitoring needs.

ABSTRACTKiller whales (Orcinus orca) have been documented to prey on white sharks (Carcharodon carcharias), in some cases causing localised shark displacement and triggering ecological cascades. Notably, a series of such predation events have been reported from South Africa over the last decade, with killer whales specifically targeting sharks' liver. However, observations of these interactions are rare, and knowledge of their frequency across the world's oceans remains limited. In October 2023, a 4.7 m (total length) white shark carcass washed ashore in southeastern Australia, coinciding with reports from citizen scientists of killer whales hunting a large, unidentified prey item in the area. Visual inspection of the carcass revealed that the liver, digestive, and reproductive organs were missing, and the presence of four distinctive bite wounds, one of which was characteristic of killer whale liver extraction as seen in South Africa. Genomic analyses performed on swabs taken from the bite wounds confirmed the presence of killer whale DNA in the major bite area, while the other bites were embedded with genetic material from the scavenging broadnose sevengill shark (Notorynchus cepedianus). These results provide confirmed evidence of killer whale predation on white sharks in Australia and the likely selective consumption of the liver, suggesting predations of this nature are more globally prevalent than currently assumed.

Estuarine ecosystems are often characterised by endemic foundation organisms which facilitate ecosystem interactions and processes established over millennia. Introduction of non-native foundation species can significantly alter ecological communities and functions. Here, we assessed the effects of introduced, reef-forming Pacific oyster Magallana gigas, within a temperate Australian mangrove-dominated estuary. Specifically, we investigated whether mangrove-attached M. gigas oyster reefs influenced intertidal fish and invertebrate communities, and fish foraging behaviour. We measured and contrasted the benthic structure and faunal communities of fringing bare sediment, Avicennia marina mangrove and Pacific oyster M. gigas reef habitats using a combination of quadrats, fyke nets and remote unbaited video (RUV) surveys. Pacific oyster reefs showed no impacts on pneumatophore density or morphology, but were positively associated with higher seedling densities. Furthermore, invertebrate and fish community metrics (e.g. richness, biomass, length) were typically higher in M. gigas reefs compared to the other habitats. However, several mobile, non-native species were predominantly detected in M. gigas reefs, including exotic gobies and European shore crabs Carcinus maenas, a declared marine pest. Overall, we found that M. gigas reefs in fringing mangrove forests were associated with biodiverse faunal communities, including fisheries-targeted species, but also facilitated other non-native species. These outcomes highlight some of the ecological pros and cons of non-native oyster reefs and the complexity of managing estuaries globally where Pacific oysters increasingly co-occur with endemic habitat-forming species.

Understanding the biological connections between populations is essential to wildlife management and conservation. Genetic studies play a central role in characterizing these connections, but typically require stratified sampling regimes to assess the spatial extent and strength of gene flow, and the relative influences of sex and ontogeny on patterns of connectivity. Yet, this can be challenging in some study systems, particularly in large marine species such as sharks, where genetic studies often rely on opportunistic and/or sampling conducted over large spatial scales. We demonstrate the importance of stratified sampling to identify previously undetected genetic structure in tiger sharks (Galeocerdo cuvier) off eastern Australia, where panmixia has been previously reported. We performed population genomic analyses on 414 tiger sharks, representing males and females and both juvenile-subadult and adult-life stages, and 21 locations spanning approximately 3000 km of eastern Australia and the Indo-Pacific region. Similar to previous studies, we demonstrate a lack of overall genetic structure across the sampling area; however, our analysis shows evidence of spatial autocorrelation and local genetic structuring in juvenile-subadult female tiger sharks. These results point to potential influences of sex and ontogeny on patterns of population genetic structure and connectivity in Australian tiger sharks. We discuss these findings in the context of essential habitats supporting tiger shark populations and risks of overstating the strength of biological connections among shark populations in the absence of appropriate sampling regimes.