The inherent susceptibility of white sharks (Carcharodon carcharias), coupled with reported declines in abundance, has led to their global listing as “Vulnerable”, prompting substantial conservation efforts. However, white sharks' propensity to use coastal areas overlaps with human activities, causing safety concerns. In New South Wales (NSW), Australia, they are caught as part of the world's longest-running meshing bather protection program. After an unprecedented spate of shark bites in 2015, Shark-Management-Alert-in-Real-Time (SMART) drumline trials started in NSW as a novel catch-and-release program aimed at non-lethal bather protection. Using seven years of data, this study analyzed SMART drumline recapture events to describe white shark habitat use along the NSW coastline. In total, 890 individuals were tagged with a recapture rate of 24.5% (n = 218). Smaller individuals (fork length < 225 cm) and females were more commonly recaptured, suggesting size and sex-specific habitat preferences. Although recaptures occurred year-round and throughout the entire NSW coast, most occurred during the Austral winter and spring and along the northern NSW coast. There were few consecutive recaptures recorded in the same location, suggesting that white sharks move throughout relatively large ranges within coastal areas. Linear distances between recaptures were on average ~220 (SE ± 25) km, mostly representing northward travels. Despite some variation, most recaptures (~77%) were recorded within a year and ~45% within 90 days. These results are consistent with the described movement ecology for the species along NSW, corroborating the seasonal importance of NSW northern coast for juvenile white sharks, and the potential effect that the Eastern Australian Current has on their distribution. This study provides important insights into immature white sharks' ecology in inshore areas, highlighting the value of capture-mark-recapture data collected from SMART drumlines to forecast shark movement for enhanced bather safety and species management.

Body size and temperature set metabolic rates and the pace of life, yet our understanding of the energetics of large fishes is uncertain, especially of warm-bodied mesotherms, which can heavily influence marine food webs. We developed an approach to estimate metabolic heat production in fishes, revealing how routine energy expenditure scales with size and temperature from 1-milligram larvae up to 3-tonne megaplanktivorous sharks. We found that mesotherms use approximately four times more energy than ectotherms use and identified a scaling mismatch in which rates of heat production increase faster than heat loss as body size increases, with larger fish becoming increasingly warm bodied. This scaling imbalance creates an overheating predicament for large mesotherms, helping to explain their cooler biogeographies. Contemporary mesotherms face high fuel demands and overheating risks, which is a concern given their disproportionate demise during prior climate shifts.

Abstract Background Biologging and telemetry have transformed our understanding of marine megafauna movement ecology. Yet, methodological constraints continue to limit data quality and deployment duration. Devices recording whale shark (Rhincodon typus) behaviours and movements have been used for decades, but they remain challenging to deploy and vary in success. Recently, spring-loaded clamp-based systems have emerged as one of the most widely used approaches to attach electronic tags to the fins of this globally endangered species. Currently, however, no consensus guidelines exist as to how to optimise this approach, potentially leading to continued underperforming deployments limiting analysis potential. Here, we synthesise experiences with clamp-based tagging worldwide through a targeted survey of whale shark researchers. We explore performance and challenges with a view to propose current best practices in the field. Results Whale shark researcher responses to the survey highlighted clamp-based systems as a practical and more widely applicable approach than drill-based methods, which are often used to secure tags to other large sharks. They also noted that clamps have greater retention potential and are suitable for a wider range of tags compared to dart-based methods, but are still constrained by design, placement, and deployment conditions. Researchers used a variety of materials and designs to build their own clamps, often facilitated by direct collaboration with each other or key manufacturers. Clamps produced highly variable outcomes, ranging from successful long-term satellite transmissions over 200 days and short-term biologging for 48 h at 20 Hz, to premature detachment and cases of fin damage. For long-term clamps, changes in position on the fin allowed for more stable satellite transmissions over time. Some clamp designs achieved data quantity and quality close to that of drilled deployments, demonstrating their potential to rival traditional methods while offering a less invasive approach. Results emphasised the ongoing need for technological refinement and rigorous evaluation of clamp performance and associated impacts. Conclusions Based on collective insights, we present a unified approach to clamp design and positioning, and identify key priorities for advancing this attachment technology, such as aiming for positions b-2 and c-2 on the fin and ensuring the clamp bridge distance (always between 30 and 50 mm) and tension are matched to shark size. Optimising clamp systems could substantially improve our ability to generate high-quality, long-duration movement data while minimising tagging impacts on the animal where possible. This could enhance ecological and conservation research outcomes for endangered whale sharks, with broader implications for tagging other large-bodied marine megafauna.

Marine megafauna adopt diverse movement strategies to balance the costs and benefits of migration amid shifting environments, resources, and reproductive demands. Species with broad latitudinal ranges can exhibit distinct movement patterns at the edges of their distribution. However, pan-latitudinal perspectives on annual movements remain scarce, as exemplified by the planktivorous basking shark Cetorhinus maximus, for which most data derive from temperate waters near the range centre. We satellite-tracked 13 basking sharks tagged near their northern distributional limit in northern Norway for up to 515 d to investigate year-round horizontal and vertical movements. Six of 7 sharks, each tracked for >= 338 d, performed large-scale return movements-departing the Norwegian shelf after summer, occupying the West European Basin and adjacent waters during winter, and returning to the Norwegian Sea the following summer. Individuals covered annual distances averaging similar to 14000 km, including one transatlantic movement to the southern Sargasso Sea. Vertically, sharks exhibited irregular surface use and isobath tracking in boreal shelf habitats, and mesopelagic occupancy with diel vertical migration in lower-latitude oceanic waters, consistent with known prey distributions. Seasonal movements averaged 30 degrees of latitude, exceeding those of lower-latitude conspecifics, thereby providing first evidence of 'leapfrog migration' in basking sharks. These comparably consistent latitudinal movements likely track large seasonal shifts in prey availability within a 2-25 degrees C thermal envelope. As climate change and other anthropogenic pressures alter marine habitats and phenologies, these findings advance understanding of range-edge movement dynamics and underscore the value of long-term, pan-latitudinal studies for assessing population connectivity and guiding dynamic conservation strategies for this endangered megaplanktivore.

Populations of large pelagic sharks are declining worldwide due to overfishing. Determining the overlap between shark populations and fishing activities is important to inform conservation measures. However, for many threatened sharks the whereabouts of particularly vulnerable life-history stages – such as pregnant females and juveniles – are poorly known. Here, we investigated the spatial distribution of size classes, energy transfer and reproductive states of pregnant females of the endangered shortfin mako, Isurus oxyrinchus, using spatially resolved catch data from a Spanish surface longline vessel (1996 − 2009) in the South-east Pacific Ocean. Our results suggest a general eastward gradient of occurrence of pregnant females of thousands of kilometers from western oceanic feeding grounds towards the eastern Pacific, where we observed an aggregation area of small juveniles. Moreover, the potential nursery likely overlapped a longline fishing hotspot, increasing the vulnerability of juveniles from fisheries. Our results suggest that limiting fishing pressure in this area could reduce mortality of early life stages and contribute to the conservation of this endangered shark species.

Deep-sea elasmobranchs (DSE) play a crucial role in marine ecosystems. However, they are poorly studied and face threats from overfishing, emphasizing an urgent need for improved scientific information, monitoring, and management strategies to reduce their bycatch. This study aimed to assess DSE bycatch from crustacean bottom trawling in southern Portugal, considering depths above and below 800 m (Regulation 2016/2336). Potential bycatch of deep-sea sharks was evaluated using in situ observations from the months of February and March and extrapolated for the fishing ban period (2017-2022). A total of 1559 specimens belonging to 18 DSE species were collected from 77 hauls between June 2020 and May 2022. Despite trawlers preferences for fishing above 800 m in the South, fishing below 800 m in the Southwest resulted in increased bycatch of DSE, including protected, uncommon, and endangered species such as Deania calceus, Mitsukurina owstoni, and Centroscymnus coelolepis. Furthermore, the areas and depth strata occupied by species like Galeus melastomus and Scymnodon ringens, suggested habitat flexibility, while others showed an apparent preference for specific depths and areas. These findings highlight the complexity of managing DSE populations amidst fishing pressures and depth restrictions. Despite the ban imposed to fishing below 800 m, bottom trawling persisted, leading to a potential elevated bycatch of deep-sea sharks for the months of February and March. This study emphasizes the urgency for improved enforcement of regulations in Portuguese waters and calls for the implementation of effective bycatch mitigation and fisheries management practices to safeguard DSE populations.

Aquatic biodiversity assessments are often labor‐intensive due to the large size of the equipment and the complex logistics of sea vessel operations. Traditional drift and drop cameras are typically tethered to the surface, causing cable and line clutter on sea vessels. At the same time, landers rely on auto‐release mechanisms that use costly acoustic signals or inaccurate galvanic reactions. We introduce a reusable, novel, and low‐cost Multipurpose Auto‐Release System, a versatile and programmable solution for diverse payloads and applications in shallow and mesophotic waters. Building on existing drop‐cam and Baited Remote Underwater Video System techniques, we enhance them with natural ballasts and an electronically controlled timed‐release mechanism, which is programmed via a smartphone app using Near Field Communication. Our technique allows tetherless retrieval from small sea vessels at the sea surface. This innovation simplifies aquatic monitoring logistics by eliminating the need for surface buoys or equipment retrieval from the seabed during each deployment. Our approach also advances benthic and deep‐sea marine biodiversity assessments by enabling easy systems deployment and recapture without pingers. We validated the system through 10 seawater tests, reaching depths of 278 m, accumulating 6 h of submerged data collection, and 17 d during continuous water immersion. We provide a detailed guide for building this robust, reusable, user‐friendly tool for diverse aquatic monitoring assessments. Additionally, we share key lessons learned, paving the way toward more democratized, customizable, and widely accessible applications capable of reaching the deepest seas.

Understanding the movement ecology of marine megaplanktivores is essential for conserving these ecologically significant species and managing their responses to environmental change. While telemetry has advanced our knowledge of filter-feeding mammal migrations, the annual movement patterns of large filter-feeding sharks, such as basking sharks (Cetorhinus maximus), remain poorly understood. This is particularly the case near their high latitude range limits where climate impacts are intensifying. In this study, we deployed pop-up satellite archival tags (PSATs) on C. maximus in northern Norway to investigate individual movement patterns and possible environmental drivers over an entire annual cycle. Geolocated tracks from two females revealed contrasting migration strategies: one shark performed a return migration spending boreal winter close to the Azores, while the other resided north of the Arctic Circle until January before moving to the North Sea in spring. Across these diverse habitats, both sharks utilized a wide thermal range. This included previously unrecorded short-term exposures to sub-zero temperatures, extending the known thermal tolerance of the species. High-resolution time series data from recovered PSATs enabled the use of advanced signal processing and gradient-based filtering techniques to investigate vertical movement patterns in relation to the physical and biological environment. In oceanic habitats, elevated use of the mesopelagic was observed together with diel vertical migration, whereas in shelf areas depth-use patterns were confined by topography and more variable, reflective of more dynamic hydrographic conditions and prey distributions. With zooplankton distributions being structured by ambient light, density gradients, and local topography, the alignment of frequented depths with isolumes, mixed layer depths, bathymetric contours, and bioluminescence events suggests these sharks actively track prey layers across diverse habitats. Recorded eurythermy and behavioural plasticity suggest C. maximus to be well-adapted to dynamic ocean conditions. These traits may be critical for responding to the rapid climate-driven changes in the abiotic and biotic environments in high-latitudes, providing insights into how these endangered filter-feeders might navigate shifting ecosystems.

Species distribution models (SDMs) are an important tool for marine conservation and management, yet guidance on leveraging diverse data to build robust models is limited. We evaluated whether an integrated SDM (iSDM) framework outperforms traditional data pooling or ensemble approaches when synthesizing multiple data types. We trained traditional SDMs and iSDMs using three data types for the blue shark (Prionace glauca) in the North Atlantic: fishery-dependent marker tags, observer records, and fishery-independent electronic tags. We compared pooled and ensembled SDMs, built with boosted regression trees, to an iSDM explicitly designed to address data-specific biases while leveraging each dataset’s strengths. While all approaches produced robust models, performance varied among data types, with fishery-dependent data consistently yielding more accurate than fishery-independent data. Differences in performance stemmed from models’ abilities to capture spatiotemporal dynamics in training data. iSDMs accounting for seasonal variability yielded the most accurate estimates but were computationally intensive, emphasizing the need to align model purpose with integration methods. Our findings reveal key trade-offs in data integration methods, particularly in balancing predictive accuracy and feasibility. As diverse data sources grow, leveraging robust approaches will be vital for improving conservation and management strategies and understanding dynamic species distributions in a changing ocean.

The northeast Atlantic Ocean contains multiple habitats considered critical for shark conservation, including nursery areas, migratory corridors and aggregation sites. In this context, updating knowledge on shark diversity and the threats affecting them in this region is essential to defining priorities and implementing the right management and conservation measures. Here, we show that Macaronesian and Cabo Verde marine ecoregions are home to 78 shark species (comprising 26 families), and 56% are threatened with extinction. The Canary Islands revealed the greatest richness (with 56 species), followed by Cabo Verde (53), Madeira (52), and the Azores (45). Cabo Verde presents fewer similarities with the rest of the islands. We also found that: i) Azores share more species with the Canary Islands than Madeira (despite the greater geographical proximity with the latter), and ii) there are no oviparous species in the Cabo Verde archipelago, contrary to the Canary Islands (5), the Azores (4), and Madeira (3). Fishing and habitat degradation are the most relevant anthropogenic pressures for the region, with Cabo Verde having the highest number of endangered species (66%) and a greater magnitude and diversity of threats. As such, this archipelago presents the highest priority area for shark conservation due to the intense industrial fishing in its waters, poor management measures in combination with its greater vulnerability to climate change.

Elasmobranch diversity has been poorly investigated within the Seychelles archipelago. The present study aimed to describe the spatial-temporal changes in the species richness and abundance of elasmobranchs on Frégate Island, Seychelles. Baited Remote Underwater Video Systems (BRUVS) were performed between May 2019 and December 2022. A total of 18 elasmobranch species were observed, comprising nine sharks and nine rays. Most species face extinction risks according to IUCN criteria; 50% are categorized as Vulnerable, 28% as Endangered, and 11% as Critically Endangered. Higher relative abundances were detected for the grey reef shark ( Carcharhinus amblyrhynchos ), followed by the nurse shark ( Nebrius ferrugineus ), short-horned pygmy devil ray ( Mobula kuhlii ), whitetip reef shark ( Triaenodon obesus ), and the critically endangered white-spotted guitarfish ( Rhyncobatus australiae ). While month and year did not affect elasmobranch relative abundance (MaxN), elevated temperatures (~ 30 ºC) significantly reduced elasmobranch MaxN. Moreover, habitat substrate was the best predictor of elasmobranch MaxN. Sharks were often encountered on rock and rubble, while batoids were more likely found on rock and sand. The presence of juvenile tiger sharks was consistent in all sampled years, but with low MaxN values. Our findings highlight the significant conservation concerns for elasmobranch species in the region and emphasize the urgent need for protective measures within the Seychelles Archipelago.

Open ocean ecosystems represent the largest habitat on Earth and are highly dynamic in time and space. Mesoscale eddies are a primary driver of this variability and serve a key structural role in ocean ecosystems. Eddies modulate marine biodiversity beyond their impacts on plankton, influencing many ecologically and commercially important predators that may preferentially occupy anticyclonic eddies. However, how animal-eddy interactions scale across predator species and the mechanistic drivers of these relationships remain an area of active research. We integrated satellite tracking data for sharks with observations of mesoscale eddies to determine how four shark species interact with eddies in the Gulf Stream region. Based on over 24,000 tracking days, we found that blue, white, and shortfin mako sharks selected for the cores of anticyclones while the use of eddies by tiger sharks was less conspicuous. Some particularly large and long-lived anticyclones were occupied by tagged sharks for multiple weeks suggesting that these eddies may serve as hotspots for pelagic predators.

Levels of dissolved oxygen in open ocean and coastal waters are decreasing (ocean deoxygenation), with poorly understood effects on marine megafauna. All of the more than 1000 species of elasmobranchs (sharks, skates, and rays) are obligate water breathers, with a variety of life-history strategies and oxygen requirements. This review demonstrates that although many elasmobranchs typically avoid hypoxic water, they also appear capable of withstanding mild to moderate hypoxia with changes in activity, ventilatory responses, alterations to circulatory and hematological parameters, and morphological alterations to gill structures. However, such strategies may be insufficient to withstand severe, progressive, or prolonged hypoxia or anoxia where anaerobic metabolic pathways may be used for limited periods. As water temperatures increase with climate warming, ectothermic elasmobranchs will exhibit elevated metabolic rates and are likely to be less able to tolerate the effects of even mild hypoxia associated with deoxygenation. As a result, sustained hypoxic conditions in warmer coastal or surface-pelagic waters are likely to lead to shifts in elasmobranch distributions. Mass mortalities of elasmobranchs linked directly to deoxygenation have only rarely been observed but are likely underreported. One key concern is how reductions in habitat volume as a result of expanding hypoxia resulting from deoxygenation will influence interactions between elasmobranchs and industrial fisheries. Catch per unit of effort of threatened pelagic sharks by longline fisheries, for instance, has been shown to be higher above oxygen minimum zones compared to adjacent, normoxic regions, and attributed to vertical habitat compression of sharks overlapping with increased fishing effort. How a compound stressor such as marine heatwaves alters vulnerability to deoxygenation remains an open question. With over a third of elasmobranch species listed as endangered, a priority for conservation and management now lies in understanding and mitigating ocean deoxygenation effects in addition to population declines already occurring from overfishing.

Abstract Background Studying habitat use and vertical movement patterns of individual fish over continuous time and space is innately challenging and has therefore largely remained elusive for a wide range of species. Amongst sharks, this applies particularly to smaller-bodied and less wide-ranging species such as the spurdog (Squalus acanthias Linnaeus, 1758), which, despite its importance for fisheries, has received limited attention in biologging and biotelemetry studies, particularly in the North-East Atlantic. Methods To investigate seasonal variations in fine-scale niche use and vertical movement patterns in female spurdog, we used archival data from 19 pregnant individuals that were satellite-tagged for up to 365 days in Norwegian fjords. We estimated the realised niche space with kernel densities and performed continuous wavelet analyses to identify dominant periods in vertical movement. Triaxial acceleration data were used to identify burst events and infer activity patterns. Results Pregnant females frequently utilised shallow depths down to 300 m at temperatures between 8 and 14 °C. Oscillatory vertical moments revealed persistent diel vertical migration (DVM) patterns, with descents at dawn and ascents at dusk. This strict normal DVM behaviour dominated in winter and spring and was associated with higher levels of activity bursts, while in summer and autumn sharks predominantly selected warm waters above the thermocline with only sporadic dive and bursts events. Conclusions The prevalence of normal DVM behaviour in winter months linked with elevated likely foraging-related activity bursts suggests this movement behaviour to be foraging-driven. With lower number of fast starts exhibited in warm waters during the summer and autumn months, habitat use in this season might be rather driven by behavioural thermoregulation, yet other factors may also play a role. Individual and cohort-related variations indicate a complex interplay of movement behaviour and habitat use with the abiotic and biotic environment. Together with ongoing work investigating fine-scale horizontal movement as well as sex- and age-specific differences, this study provides vital information to direct the spatio-temporal distribution of a newly reopened fishery and contributes to an elevated understanding of the movement ecology of spurdog in the North-East Atlantic and beyond. Graphical Abstract

Abstract Global climate‐driven ocean warming has decreased dissolved oxygen (DO) levels (ocean deoxygenation) leading to expansions of hypoxic zones, which will affect the movements, behaviour, physiology and distributions of marine animals. However, the precise responses of animals to low DO remains poorly understood because movements and activity levels are seldom recorded alongside instantaneous DO in situ. We describe a new animal‐attached (dissolved oxygen measuring, DOME) archival tag with an optical oxygen sensor for recording DO, in addition to sensors for temperature and depth, a triaxial accelerometer for fine‐scale movements and activity, and a GPS for tag recovery. All sensors were integrated on a single electronic board. Calibration tests demonstrated small mean difference between DOME tag and factory‐calibrated DO sensors (mean relative error of 5%). No temporal drift occurred over a test period three times longer than the maximum deployment time. Deployments on four blue sharks (Prionace glauca) in the central North Atlantic Ocean showed regular vertical oscillations from the surface to a maximum of 404 m. Profiles from diving sharks recorded DO concentrations ranging from 217 to 272 μmol L−1, temperatures between 13°C and 23°C, and identified an oxygen maximum at ~45 m depth, all of which were consistent with ship‐based measurements. Interestingly, the percentage of time sharks spent burst swimming was greater in the top 85 m compared to deeper depths, potentially because of higher prey availability in the surface layer. The DOME tag described blue shark fine‐scale movements and activity levels in relation to accurately measured in situ DO and temperature, with the potential to offer new insights of animal performance in low oxygen environments. Development of a tag with physico‐chemical and movement sensors on a single electronic board is a first step towards satellite relay of these data over broader spatiotemporal scales (months over thousands of kilometres) to determine direct and indirect responses of marine animals to heatwave and deoxygenation events.

Many predator species make regular excursions from near-surface waters to the twilight (200 to 1,000 m) and midnight (1,000 to 3,000 m) zones of the deep pelagic ocean. While the occurrence of significant vertical movements into the deep ocean has evolved independently across taxonomic groups, the functional role(s) and ecological significance of these movements remain poorly understood. Here, we integrate results from satellite tagging efforts with model predictions of deep prey layers in the North Atlantic Ocean to determine whether prey distributions are correlated with vertical habitat use across 12 species of predators. Using 3D movement data for 344 individuals who traversed nearly 1.5 million km of pelagic ocean in > 42,000 d, we found that nearly every tagged predator frequented the twilight zone and many made regular trips to the midnight zone. Using a predictive model, we found clear alignment of predator depth use with the expected location of deep pelagic prey for at least half of the predator species. We compared high-resolution predator data with shipboard acoustics and selected representative matches that highlight the opportunities and challenges in the analysis and synthesis of these data. While not all observed behavior was consistent with estimated prey availability at depth, our results suggest that deep pelagic biomass likely has high ecological value for a suite of commercially important predators in the open ocean. Careful consideration of the disruption to ecosystem services provided by pelagic food webs is needed before the potential costs and benefits of proceeding with extractive activities in the deep ocean can be evaluated.

Tuna Regional Fishery Management Organizations (tRFMOs) are increasingly interested in spatiotemporal management as a tool to reduce interaction rates with vulnerable species. We use blue shark ( Prionace glauca ) as a case study to demonstrate the critical first steps in the implementation process, highlighting how predictions of global habitat for vulnerable life stages can be transformed into a publicly -accessible spatial bycatch mitigation tool. By providing examples of possible management goals and an associated threshold to identify essential habitats, we show how these key areas can represent a relatively low percentage of oceanic area on a monthly basis (16-24% between 50 degrees S and 60 degrees N), yet can have relatively high potential protection efficiency (similar to 42%) for vulnerable stages if fishing effort is redistributed elsewhere. While spatiotemporal management has demonstrable potential for blue sharks to effectively mitigate fishing mortality on sensitive life stages, we identify inherent challenges and sequential steps that require careful consideration by tRFMOs as work proceeds. We also discuss how our single-species framework could be easily extended to a multispecies approach by assigning relative conservation risk before layering habitat model predictions in an integrated analysis. Such broader application of our approach could address the goals of tRFMOs related to reducing the ecosystem effects of fishing and pave the way for efficient fisheries co-management using an ecosystem-based approach.

Climate change is shifting animal distributions. However, the extent to which future global habitats of threatened marine megafauna will overlap existing human threats remains unresolved. Here we use global climate models and habitat suitability estimated from long-term satellite-tracking data of the world's largest fish, the whale shark, to show that redistributions of present-day habitats are projected to increase the species' co-occurrence with global shipping. Our model projects core habitat area losses of >50% within some national waters by 2100, with geographic shifts of over 1,000 km (similar to 12 km yr(-1)). Greater habitat suitability is predicted in current range-edge areas, increasing the co-occurrence of sharks with large ships. This future increase was similar to 15,000 times greater under high emissions compared with a sustainable development scenario. Results demonstrate that climate-induced global species redistributions that increase exposure to direct sources of mortality are possible, emphasizing the need for quantitative climate-threat predictions in conservation assessments of endangered marine megafauna.

Antillean manatees (Trichechus manatus manatus) are endangered coastal, marine, and riverine megaherbivores with high environmental plasticity, constrained by tidal and seasonal water level cycles that affect access to food and fresh water. Accurate quantification of the species' habitat requirements, typically achieved through home range (HR) estimation, is required to implement area-based conservation initiatives. In this study, we used GPS tracking data from 38 wild and captive-rehabilitated released manatees to estimate HR using autocorrelated kernel density estimators (AKDE) and average time speed. We investigated whether body size, habitat type, sex and behavioural group influence home range size due to energy requirements, resources availability, a scramble-competitive polygyny mating system, and adaptation to the wild. Eighteen manatees exhibited range-resident behaviour, with a mean 95% home range of 72.96 km2 (+/- 218.52) and a median of 10.69 km2. The mean daily speed was estimated to be 13.47 km/day (+/- 4.16). Home range and body size were positively correlated, consistent with HR allometry theory. Long-term tracked individuals showed a trend of increasing HR over time. Only four released animals (17.4%) were range-resident, suggesting that they may need additional time to establish a home range. Individuals using only the marine environment had larger home ranges compared to mixed (marine and estuarine) and estuarine environments, probably due to freshwater availability. Our study contributes to the understanding of the factors driving manatee movement and provides more accurate estimates of area requirements, which can inform the establishment and zoning of marine protected areas.