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Rapid global expansion of offshore wind farms, tidal, and wave technologies signifies a new era of renewable energy development. While a promising means to combat the impacts of climate change, such developments necessitate fine-scale monitoring of biological communities to determine impacts associated with construction, operation, and eventual decommission. Here, we evaluate the performance of a gridded, Innovasea Systems, Inc. fine-scale acoustic telemetry positioning system (FSPS, n = 20 acoustic receivers) for tracking behaviors of diverse, temperate fish assemblages in relation to a subsea cable route supporting the Ørsted offshore wind development in coastal New York. We examined array performance through positioning error derived from receiver reference transmitters and tracked animals (n = 260) comprising 17 species of teleost and elasmobranch. We evaluated the effects of environmental variables (temperature, tilt, noise, and depth), transmitter power, individual movement rates, and receiver loss on horizontal positioning error (HPE) and route mean squared error (RMSE). Across a 16-month deployment period, many positions were derived for Atlantic sturgeon (n = 2,612), black sea bass (n = 9,175), clearnose skate (n = 10,306), summer flounder (n = 13,304), and little skate (n = 15,186), suggesting that these species may serve as sentinel candidates for assessing behavioral changes following construction, operation, and decommission. We found that receivers placed at the boundary of the grid exhibited higher HPE and RMSE, however these errors did not significantly change despite large receiver losses (25%). Generalized Linear Models revealed that temperature, noise, tilt, and depth were often significant predictors of HPE and RMSE, however, a substantial amount of variance was not explained by the models (~ 70%). Average movement rates ranged from 1.1 m s−1 (common thresher shark) to 0.03 m s−1 (little skate and summer flounder) but had minimal effects on positioning error. Finally, we observed that higher transmitter powers (158 dB) may lead to higher and more variable HPE values. Overall, these findings provide new insight into the drivers of FSPS array performance and illustrate their broad utility for monitoring fish behavior associated with offshore marine developments. [ABSTRACT FROM AUTHOR]

Classifying animal behaviors in their natural environments is both challenging and ecologically important, but the use of biologgers with multiple sensors has significantly advanced this research beyond the capabilities of traditional methods alone. Here, we show how biologgers containing an integrated tri-axial accelerometer, GPS logger and immersion sensor were used to infer behavioural states of a cryptic, freshwater turtle, the Blanding's turtle (Emydoidea blandingii). Biologgers were attached to three males and five females that reside in two undisturbed coastal marshes in northeastern Georgian Bay (Ontario, Canada) between May and July 2023. Raw acceleration values were separated into static and dynamic acceleration and subsequently used to calculate overall dynamic body acceleration (ODBA) and pitch. The unsupervised Hidden Markov Model (HMM) successfully differentiated five behavioural states as follows: active in water, resting in water, active out of water, resting in water, and nesting. Overall accuracy of the classification was 93.8%, and except for nesting (79%), all other behaviours were above 92%. There were significant differences in daily activity budgets between male and female turtles, with females spending a greater proportion of time active out of water, and inactive out of the water, while males spent a greater proportion of time active in water. These differences were likely a result of large seasonal life-history requirements such as nesting and mate finding. Accurate classification of behavioural states is important for researchers to understand fine-scale activities carried out during the active season and how environmental variables may influence the behaviours of turtles in their natural habitats. [ABSTRACT FROM AUTHOR]

Background: Triaxial accelerometers have revolutionized wildlife research by providing an unprecedented understanding of the behavior of free-living animals. Machine learning is often applied to acceleration data to classify diverse animal behaviors across taxa. However, the high frequency, continuous data collection typically favored for behavioral classification studies often generates very large data sets, which may inhibit remote data acquisition and make data storage challenging. Coarse-frequency sampling or non-continuous bursts of acceleration data reduce these problems. To analyze such data, a suite of variables that summarize key features of the behavior of interest can be generated. These variables can then be used in numerous classification approaches, accommodating variation in data collection methods or sampling regimes. We demonstrate the potential for non-continuous accelerometer data to identify long-duration behavior and employ machine learning to classify the nesting behaviors of the critically endangered eastern Santa Cruz giant tortoise (Chelonoidis donfaustoi). Results: We field validated 112 nesting events from 21 giant tortoises. We then derived summary statistics based on accelerometry (e.g., overall dynamic body acceleration, metrics comparing acceleration before and after the probable event) and used them as inputs for Random Forest and Boosted Regression Tree classification algorithms. Our models produced a harmonic mean of precision and sensitivity (F1-score) of 0.91. We tested the generality of our model and found that the model performs well when applied to both novel individuals and years. The most important variable in accurately classifying data sequences was the proportion of acceleration data bursts above an activity threshold followed by the average overall dynamic body acceleration value of the bursts. Conclusions: These results demonstrate the feasibility and efficacy of using non-continuous accelerometer data to identify prolonged, biologically relevant behaviors in free-living wildlife. By using summary variables that do not require continuous sampling, this approach facilitates long-term monitoring of animal behavior. Similar methodology has potential to inform priority questions in ecology and conservation, such as predicting wildlife responses to climate change and identifying critical habitats, with applications across diverse species and behaviors. [ABSTRACT FROM AUTHOR]

Context: Coastal beach environments provide habitats for marine megafauna, including turtles, rays, marine mammals and sharks. However, accessing these variable energy zones has been difficult for researchers by using traditional methods. Aims: This study used drone-based aerial surveys to assess spatio-temporal variation of marine megafauna across south-eastern Queensland, Australia. Methods: Drones were operated at five south-eastern Queensland beaches. Megafauna sightings and key variables including location, month and turbidity were analysed to assess variation across locations. Key results: Overall, 3815 individual megafauna were detected from 3273 flights. There were significant differences in the composition of megafauna assemblages throughout the year and among beaches, with megafaunal sightings in >80% of flights conducted off North Stradbroke Island. Conclusions: Strong temporal presence was found that is congruent with other studies examining seasonality. This supports the use of drones to provide ecological data for many hard-to-study megafauna species and help inform long-term sustainable management of coastal ecosystems. Implications: Results indicated that environmental conditions can influence the probability of sighting marine megafauna during aerial surveys. Studying beach environments by using boat-based methods has been difficult. Drone surveys were used to assess abundance patterns of large marine animals in south-eastern Queensland, Australia. Significant differences in the composition of animal groups were found throughout the year and among locations, with large marine animal sightings in >80% of flights conducted off North Stradbroke Island. This supports the use of drones to provide scientific data for hard-to-study marine species and inform management of coastal ecosystems. [ABSTRACT FROM AUTHOR]

Context: Understanding the movement behaviour of flow-dependent fish species is a foundational principle underlying the effective management of highly modified riverscapes. Aims: To determine how variations in river discharge and instream barriers affect the residency, survival and movement of golden perch (Macquaria ambigua) in the degraded Gwydir River system within the northern Murray–Darling Basin. Methods: We monitored the movement of 25 acoustic-tagged golden perch for up to 3 years by using a linear array spanning ~180 km of the main river channels across the lower Gwydir system. Key results: Golden perch were largely sedentary for extended periods, with movements constrained by the barrier maze that now defines the system. High flows facilitated passage over instream barriers, with the highest periods of activity occurring in spring and early summer, and to a lesser extent in autumn. Conclusion: Our findings are indicative of a highly constrained and isolated population of golden perch that is now likely to be neither a source nor a sink, but is in effect a false sink perpetuated by re-stocking practices. Implications: The rehabilitation of the fish community in the Gwydir and other systems in similarly poor condition throughout the Murray–Darling Basin will require major institutional and societal change. We tracked golden perch in the highly modified Gwydir River to understand their response to different flows and the effect of barriers. Normally considered highly mobile, we found our golden perch to be highly constrained and largely sedentary, with little apparent connection to the wider population. The recovery and restoration of golden perch in the Murray–Darling Basin will require societal change. This article belongs to the collection Environmental flows in northern Murray–Darling Basin: what we know about the science and management after a decade of practice. [ABSTRACT FROM AUTHOR]

Tiger sharks are apex predators with a circumglobal tropical and warm-temperate distribution, with a general lack of population data for the central Indian Ocean. In Fuvahmulah, Maldives, tiger sharks display frequent use of the harbour area, attracted by discarded fish waste. Here, we document the population structure, residency, and reproductive characteristics of the world's largest known tiger shark aggregation in a geographically-restricted area. Using non-invasive methods, photo identification and laser photogrammetry, we identified 239 individual tiger sharks over a 7-year study period. The aggregation was female-dominated (84.5%), with both large juveniles and adults present. Adult females were resighted over the entire study period displaying strong inter- and intra-annual site fidelity. Modelled residency using maximum likelihood methods suggests they spent 60.7 ± S.E. 7.5 days in Fuvahmulah, with a larger aggregation size, shorter residence periods and longer absence periods compared to juvenile females. Prolonged abdominal distensions of adult females indicate they likely stay near Fuvahmulah during gestation and reproduce biennially. Fuvahmulah seems to provide suitable conditions for gestation given the year-round provision of food and warm waters, exhibited by strong site fidelity and temporal residency. Our results show indications of a thriving population within the confines of protected waters. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Carangidae is an economically important fish family comprised of 32 genera with more than 140 circumglobally distributed species. Its members exhibit vast differences in morphology and lifestyle, thus making them compelling subjects for evolutionary studies. Recently, more works on carangids have detected the presence of cryptic lineages through molecular and/or non-molecular techniques. Credited for its inherent amplification efficiency, mitophylogenomics became effective in opening avenues to further understand higher-level interrelationships in many fish groups. However, the mitophylogenomic approach has not yet been widely applied to infer evolutionary history at the lower-level interrelationships, especially on cryptic representatives. In this study, we evaluated the diagnostic applicability of mitogenomes in detecting population-level divergences within Carangidae. Using the mitogenomes, we detected intraspecific divergences on some taxa, namely Caranx melampygus, Selaroides leptolepis, Seriola lalandi, Decapterus maruadsi, and Trachurus trachurus, with divergences highly correspondent to that of their geographic origins. Additionally, a widespread Pacific arrangement was also detected for S. rivoliana. Our discoveries were highly corroborative with findings from other Carangidae studies which utilized different diagnostic markers (e.g., SNPs, microsatellites, morphometrics, parasites). Dated phylogeny also suggested that intraspecific diversifications occurred during the Late Neogene. Likewise, we characterized two mitogenomes from different cryptic lineages of Selaroides leptolepis and revealed that the two mitogenomes were K2P pairwise = 5.58% different from each other. Its genetic compositions included 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. These findings paved way for future evolutionary insights into the divergence histories of other fish populations. [ABSTRACT FROM AUTHOR]

Context: For threatened marine species, data on their vertical habitat use patterns can reveal risk of interactions with fishing gear and can inform bycatch avoidance strategies. Such data are lacking for young porbeagles (Lamna nasus), which are captured as bycatch in north-western Atlantic fisheries. Aims: We aimed to examine temporal patterns in diving and characterise vertical habitat use of young porbeagles during summer and autumn. Methods: We used data from short-term (28-day), high-resolution (5-min interval) pop-off satellite tags attached to 14 young (young-of-the-year and 1-year-old) porbeagles to model depth use. Key results: Occupied depths ranged from the sea surface to 679 m, with ambient water temperatures of −0.2 to 26°C. Diel period and season were factors related to depth use. Conclusions: Sharks exhibited a diel activity pattern characterised by more extensive use of the water column during the day while remaining primarily at the surface at night. Depth use differed between seasons, with summer characterised by greater affinity for surface waters (0–10 m) compared to autumn. Implications: Young porbeagles are at risk of interaction with active fisheries on the continental shelf, but interactions may be reduced by setting gear deeper at night or during summer. The depth use of young porbeagles was investigated for the first time during the summer and autumn in the north-western Atlantic. Depth use varied on both daily and seasonal scales, with sharks occupying surface waters during the night and summer, and diving deeper during the day and autumn. Results can inform bycatch reduction strategies for this vulnerable life stage. [ABSTRACT FROM AUTHOR]

The frequency of unprovoked shark bites is increasing worldwide, leading to a growing pressure for mitigation measures to reduce shark-bite risk while maintaining conservation objectives. Personal shark deterrents are a promising and non-lethal strategy that can protect ocean users, but few have been independently and scientifically tested. In Australia, bull (Carcharhinus leucas), tiger (Galeocerdo cuvier), and white sharks (Carcharodon carcharias) are responsible for the highest number of bites and fatalities. We tested the effects of two electric deterrents (Ocean Guardian’s Freedom+ Surf and Freedom7) on the behaviour of these three species. The surf product reduced the probability of bites by 54% across all three species. The diving product had a similar effect on tiger shark bites (69% reduction) but did not reduce the frequency of bites from white sharks (1% increase), likely because the electrodes were placed further away from the bait. Electric deterrents also increased the time for bites to occur, and frequency of reactions and passes for all species tested. Our findings reveal that both Freedom+ Surf and Freedom7 electric deterrents affect shark behaviour and can reduce shark-bite risk for water users, but neither product eliminated the risk of shark bites entirely. The increasing number of studies showing the ability of personal electric deterrents to reduce shark-bite risk highlights personal protection as an effective and important part of the toolbox of shark-bite mitigation measures. [ABSTRACT FROM AUTHOR]

Acoustic telemetry can provide valuable space-use data for a range of marine species. Yet the deployment of species-specific arrays over vast areas to gather data on highly migratory vertebrates poses formidable challenges, often rendering it impractical. To address this issue, we pioneered the use of acoustic telemetry on basking sharks (Cetorhinus maximus) to test the feasibility of using broadscale, multi-project acoustic receiver arrays to track the movements of this species of high conservation concern through the coastal waters of Ireland, Northern Ireland, and Scotland. Throughout 2021 and 2022, we tagged 35 basking sharks with acoustic transmitters off the west coast of Ireland; 27 of these were detected by 96 receiver stations throughout the study area (n = 9 arrays) with up to 216 detections of an individual shark (mean = 84, s.d. 65). On average, sharks spent ~ 1 day at each acoustic array, with discrete residency periods of up to nine days. Twenty-one sharks were detected at multiple arrays with evidence of inter-annual site fidelity, with the same individuals returning to the same locations in Ireland and Scotland over 2 years. Eight pairs of sharks were detected within 24 h of each other at consecutive arrays, suggesting some level of social coordination and synchronised movement. These findings demonstrate how multi-project acoustic telemetry can support international, cost-effective monitoring of basking sharks and other highly mobile species. Decision support tools such as these can consolidate cross-border management strategies, but to achieve this goal, collaborative efforts across jurisdictions are necessary to establish the required infrastructure and secure ongoing support. [ABSTRACT FROM AUTHOR]

Context: Satellite telemetry has revolutionised the study of animal movement, particularly for mobile marine animals, whose movements and habitat make consistent, long-term observation difficult. Aims: Summarise the movements of Rio Lady, a mature female whale shark (Rhincodon typus), to characterise these movements, and to predict expected behaviour throughout the Gulf of Mexico (GOM). Methods: Rio Lady was tracked using satellite telemetry for over 1600 days, generating over 1400 locations and travelling over 40,000 km. State–space and move persistence modelling enabled characterisation of behaviour, and machine learning (ML) enabled the development of habitat-suitability models to predict habitat utilisation, on the basis of location transmissions and their environmental covariates. Key results: Rio Lady exhibited annually consistent patterns of movements among three regions within the GOM. Final ML models produced seasonally dynamic predictions of habitat use throughout the GOM. Conclusions: The application of these methods to long-term location data exemplifies how long-term movement patterns and core areas can be discovered and predicted for marine animals. Implications: Despite our limited dataset, our integrative approach advances methods to summarise and predict behaviour of mobile species and improve understanding of their ecology. Satellite telemetry enables the study of marine species where observation is difficult owing to their movement across oceans. Rio Lady, a mature female whale shark, has been tracked for longer than any other whale shark and has generated movement data for more than four consecutive years, providing insight into the interannual movement patterns for this species. The combination of these data with machine-learning and habitat-modelling techniques provides a new framework, with potential for enabling new methods of conservation. [ABSTRACT FROM AUTHOR]

Octopuses are amongst the most fascinating animals in our oceans; however, while their intricate behaviours are often studied in laboratory settings, basic aspects of their movement ecology remain unstudied in the wild. Focusing on the socio-economically important common octopus (Octopus vulgaris), this study employs, for the first time, acoustic tracking techniques to address knowledge gaps regarding the species spatial ecology within a marine protected area. A total of 24 wild O. vulgaris (13 males, 11 females) were tagged in 2022 in the National Park Maritime-Terrestrial of the Atlantic Islands of Galicia, Spain. Acoustic transmitters were externally attached to the third arm, after testing other body parts (mantle cavity). Males were on average detected on 10 times more occasions than females (49 days in males and five in females). The average activity space in the study area was large in comparison to that determined in similar studies, with 0.16 km2. Activity space between males and females as well as day and night were comparable. Tagged octopuses displayed a crepuscular activity pattern. The location of dens could be established for 15 out of 24 individuals, from which octopuses were observed to undertake regular daytime excursions. Several individuals were also found to occupy more than one den and/or switch their main dens throughout the study duration. First implications and benefits of this approach are discussed. [ABSTRACT FROM AUTHOR]

The blue shark, Prionace glauca, is the most abundant pelagic shark in the open ocean but its vulnerability remains poorly understood while being one of the most fecund sharks. In the Mediterranean Sea, the blue shark is listed as Critically Endangered (CR) by the International Union for Conservation of Nature. The species is facing a strong decline due to fishing, and scientific data regarding its genetic structure and vulnerability are still lacking. Here, we investigated the genetic diversity, demographic history, and population structure of the blue shark within the Mediterranean Sea, from samples of the Gulf of Lion and Malta, using sequences of the mtDNA control region and 22 microsatellite markers. We also compared our mitochondrial data to previous studies to examine the Atlantic-Mediterranean population structure. We assessed the blue shark's genetic vulnerability in the Mediterranean basin by modelling its effective population size. Our results showed a genetic differentiation between the Atlantic and the Mediterranean basins, with limited gene flow between the two areas, and distinct demographic histories making the Mediterranean population an independent management unit. Within the Mediterranean Sea, no sign of population structure was detected, suggesting a single population across the Western and Central parts of the sea. The estimated effective population size was low and highlighted the high vulnerability of the Mediterranean blue shark population, as the estimated size we calculated might not be sufficient to ensure the long-term persistence of the population. Our data also provide additional evidence that the Gulf of Lion area acts as a nursery for P. glauca, where protection is essential for the conservation strategy of the species in the Mediterranean. [ABSTRACT FROM AUTHOR]

Background: Individual variation in movement strategies of foraging loggerhead turtles have been documented on the scale of tens to hundreds of kilometers within single ocean basins. Use of different strategies among individuals may reflect variations in resources, predation pressure or competition. It is less common for individual turtles to use different foraging strategies on the scale of kilometers within a single coastal bay. We used GPS tags capable of back-filling fine-scale locations to document movement patterns of loggerhead turtles in a coastal bay in Northwest Florida, U.S.A. Methods: Iridium-linked GPS tags were deployed on loggerhead turtles at a neritic foraging site in Northwest Florida. After filtering telemetry data, point locations were transformed to movement lines and then merged with the original point file to define travel paths and assess travel speed. Home ranges were determined using kernel density function. Diurnal behavioral shifts were examined by examining turtle movements compared to solar time. Results: Of the 11 turtles tagged, three tracked turtles remained in deep (~ 6 m) water for almost the entire tracking period, while all other turtles undertook movements from deep water locations, located along edges and channels, to shallow (~ 1–2 m) shoals at regular intervals and primarily at night. Three individuals made short-term movements into the Gulf of Mexico when water temperatures dropped, and movement speeds in the Gulf were greater than those in the bay. Turtles exhibited a novel behavior we termed drifting. Conclusions: This study highlighted the value provided to fine-scale movement studies for species such as sea turtles that surface infrequently by the ability of these GPS tags to store and re-upload data. Future use of these tags at other loggerhead foraging sites, and concurrent with diving and foraging data, would provide a powerful tool to better understand fine-scale movement patterns of sea turtles. [ABSTRACT FROM AUTHOR]

Background: The meagre, Argyrosomus regius, is a large coastal predatory fish inhabiting waters from the north-eastern Atlantic and Mediterranean Sea, where it is targeted by commercial and recreational fisheries. Previous genetic studies have found an unexpectedly high population differentiation not only between the Atlantic and the Mediterranean, but also along the Atlantic coast. However, the reasons underpinning this genetic barrier remained unclear. Likewise, even though the species is amongst the world's largest marine teleosts, knowledge about its movement ecology and migratory behaviour remains notably scarce, and primarily reliant on fisheries-dependent data. Methods: In this study, we used a combination of acoustic telemetry and pop-up satellite archival tags to investigate the movements of 22 adult meagre (70–143 cm total length) along the Southwestern coast of the Iberian Peninsula. Results: Our results strongly suggest that the previously reported genetic differentiation is not maintained by limited adult dispersal/movement, as hypothesized. On the contrary, we documented some of the longest individual annual migrations ever recorded for a coastal teleost, up to > 2000 km, with frequent back-and-forth movements between the West and Southern Iberian coasts. Moreover, their detected regional movement patterns support the existence of a marked seasonal behavioural shift, with individuals being less active and moving to deeper waters during winter, and are consistent with spawning philopatry associated to their summer reproductive movements. Finally, we identified putative aggregation areas that may harbour important feeding/overwintering grounds. Conclusions: These findings shed new light on the movement and behaviour patterns of meagre that may be of particular importance for the conservation and spatial management of this species throughout its range, and open the door to further research on functional connectivity. [ABSTRACT FROM AUTHOR]

While juvenile white sharks (JWS) can display regional endothermy, the need to maintain internal temperatures within an energetically favorable range likely drives thermoregulatory movements to maximize growth and foraging efficiency. Many JWS from the northeastern Pacific population aggregate seasonally in nearshore nursery habitats throughout the Southern California Bight and historic data show that inter-seasonal movement patterns may be heavily dependent on ambient water temperature. However, the degree to which micro-scale (e.g., ~10 m²) water temperature heterogeneity influences JWS three-dimensional movement within nearshore aggregation sites is unknown. High-resolution temperature and passive acoustic-telemetry geo-positional data were used to quantify how temperature and vertical thermal stratification influenced JWS movement using several modeling approaches. JWS selected for water temperatures between 16 - 22°C and depths shallower than 2 m. Sharks occupied deeper waters during dawn and dusk periods, and their distance from the seafloor and spatial orientation of their depth distribution was significantly related to the thermal structure of the water column across the monitored area. Tagged sharks remained above a 16°C thermal threshold and altered their horizontal and vertical distributions accordingly. While high-resolution movement and environmental data provide improved predictability of microscale habitat use and distribution, other variables such as prey distribution, behavior, and competition would further improve habitat use models for this highly mobile species. [ABSTRACT FROM AUTHOR]

Background: Acoustic telemetry has become a fundamental tool to monitor the movement of aquatic species. Advances in technology, in particular the development of batteries with lives of > 10 years, have increased our ability to track the long-term movement patterns of many species. However, logistics and financial constraints often dictate the locations and deployment duration of acoustic receivers. Consequently, there is often a compromise between optimal array design and affordability. Such constraints can hinder the ability to track marine animals over large spatial and temporal scales. Continental-scale receiver networks have increased the ability to study large-scale movements, but significant gaps in coverage often remain. Methods: Since 2007, the Integrated Marine Observing System's Animal Tracking Facility (IMOS ATF) has maintained permanent receiver installations on the eastern Australian seaboard. In this study, we present the recent enhancement of the IMOS ATF acoustic tracking infrastructure in Queensland to collect data on large-scale movements of marine species in the northeast extent of the national array. Securing a relatively small initial investment for expanding receiver deployment and tagging activities in Queensland served as a catalyst, bringing together a diverse group of stakeholders (research institutes, universities, government departments, port corporations, industries, Indigenous ranger groups and tourism operators) to create an extensive collaborative network that could sustain the extended receiver coverage into the future. To fill gaps between existing installations and maximise the monitoring footprint, the new initiative has an atypical design, deploying many single receivers spread across 2,100 km of Queensland waters. Results: The approach revealed previously unknown broad-scale movements for some species and highlights that clusters of receivers are not always required to enhance data collection. However, array designs using predominantly single receiver deployments are more vulnerable to data gaps when receivers are lost or fail, and therefore "redundancy" is a critical consideration when designing this type of array. Conclusion: Initial results suggest that our array enhancement, if sustained over many years, will uncover a range of previously unknown movements that will assist in addressing ecological, fisheries, and conservation questions for multiple species. [ABSTRACT FROM AUTHOR]

Background: Acoustic telemetry is an important tool to study the movement of aquatic animals. However, studies have focussed on particular groups of easily tagged species. The development of effective tagging methods for ecologically important benthic species, such as sea stars, remains a challenge due to autotomy and their remarkable capacity to expel any foreign material. We tested three methods to surgically attach acoustic transmitters to the common sea star Asterias rubens; two methods attached the tag to the aboral side of the central body and the third attached the transmitter to the aboral side of an arm. Laboratory experiments evaluated each method in terms of survivability, tag retention, associated injuries, and changes in feeding behaviour and physical condition. Results: Laboratory results were highly variable; however, all tagging methods caused significant injury to the epidermis and deeper tissue around the attachment site over periods greater than 4 weeks. Attaching a tag by horizontally piercing the central body (method HPC) had minimal effects in the short-term (2–3 weeks) and this method was used for a pilot tagging study in the field, where 10 sea stars were tagged and placed within an existing acoustic telemetry array. Although, the interpretation of field data was challenging due to the characteristic slow movement of sea stars, movements of a similar magnitude to previous studies were identified during the 2–4 weeks after sea stars were tagged and released. However, this apparent period of tagging success was followed by a reduction in movement that, when viewed in conjunction with laboratory results, potentially indicated a deterioration in the sea stars' physical condition. Conclusions: While acoustic telemetry continues to provide novel insights into the ecology of a wide variety of marine species, species-specific effects of tagging should be evaluated before starting field studies. If the autonomous study of benthic movement is to expand beyond hard-bodied macroinvertebrates current methodological and analytical challenges must be addressed. [ABSTRACT FROM AUTHOR]

Activity patterns in animals are often species-specific, and can be generally categorized as diurnal, crepuscular, or nocturnal. Understanding these patterns provides insight into ecological adaptations and behaviors. The common grass snake (Natrix natrix), one of the most common and widespread European snake species, is traditionally considered diurnal, with scarce evidence of its crepuscular and nocturnal activity. We aimed to document the distribution, environmental conditions, and potential phenotype associations of nighttime activity in N. natrix. We used citizen science data from iNaturalist (1992-2022), Observation.org (2012-2022), together with personal field observations (2010-2023) to collect 127 crepuscular and nocturnal activity records. Most observations occurred between May and August, coinciding with the peak activity period of grass snakes across their distribution range. Statistical analyses revealed no significant difference in mean daily temperatures between crepuscular and nocturnal observations. However, striped individuals displayed nocturnal activity at higher temperatures, consistent with their distribution in warmer regions, but failed to register any difference when tested on a geographic subsample, that accounted for sympatry of the phenotypes. Surprisingly, we found no significant impact of moon presence or moonlight on nighttime activity or age class, contrary to expectations based on other snake species' responses. While our study reveals that nocturnal activity in the common grass snake is geographically widespread, further research is warranted to understand its drivers and ecological implications. This study highlights the value of citizen science platforms for biological and ecological research, offering unparalleled spatial and temporal coverage by their users. In conclusion, our work extends the knowledge of nocturnal behavior in N. natrix and underlines the critical role of citizen science in discovering behavioral aspects of common and widespread species. [ABSTRACT FROM AUTHOR]

This paper studies the retrieval method of learners' behavior features in the coding library the K-means clustering algorithm, which can effectively retrieve learners' behavior features and ensure the safety and stability of the coding library. After constructing the medical coding database, using the missing forest algorithm to fill the missing data in the learner behavior data of the coding database, the improved binary K-means clustering algorithm is used, without setting the number of clusters, it is only necessary to carry out binary clustering operation on the behavior data of learners in the coding library after missing and filling, so as to obtain the behavior characteristics of learners in the coding library; These features are input as a support vector machine classifier. Through the classification training of support vector machine, the learner behavior features in the coding library can be classified and the corresponding retrieval results can be output. The experimental results show that this method can effectively retrieve learners' behavior features in the code library and identify abnormal behaviors. The retrieval accuracy and efficiency are high, and it is less affected by the signal-to-noise ratio and the amount of data. It has significant advantages in the actual learners' behavior features retrieval in the code library. [ABSTRACT FROM AUTHOR]

Seascape connectivity can facilitate key ecosystem functions in complex ecosystems like coral reefs. Many reef fishes move across the seascape, bridging different ecosystems. However, their role in shaping important functions, such as biomass production and nutrient cycling, is still poorly understood. This study, therefore, assesses the extent of natural movements of cardinalfishes (Apogonidae), one of the major contributors to nocturnal fish biomass production with the potential for a major role in transferring energy and nutrients between sandy ecosystems and adjacent coral reefs. Consistent with previous work, showing their ability to move distances of 100 s to 1000 s of metres when displaced, we reveal that these small fishes undergo major voluntary nocturnal foraging forays extending up to at least 145 m from reef structures. Their estimated daily movement distances are at least 430 times greater than expected based solely on body size-home range expectations. Given their large travel distances and strong homing abilities, apogonids may provide a major conduit for material transfer between lagoonal soft sediment habitats and adjacent coral reefs. These results highlight the potential importance of apogonids in the cross-system or cross-habitat transport of energy and nutrients on coral reefs. [ABSTRACT FROM AUTHOR]

Context: Social and economic information is limited for coastal commercial and recreational fisheries, particularly shark fisheries, which are perceived as unsustainable and as targeting sharks for fins. Aims: To characterise the social and economic dimensions of one of the world's few long-standing sustainable shark fisheries. Methods: We reviewed historic data and surveyed stakeholders to understand the economic and social dimensions of the shark fishery currently operating in Western Australia. Key results: Since the fishery's historic peak, there has been a substantial reduction in the number of operating vessels and ports due to management intervention. For the vessels that have remained, catches and catch rates increased through time. Fishers sold only flesh and fins, whereas processors also sold cartilage. Revenue mostly originates from the domestic sale of flesh, not fins. This fishery provides additional social and economic returns through the employment of an average of 102 people per annum, the supply of local fresh seafood to communities and the expenditure of most of operational costs in local government areas. In addition, the average annual market value through the supply chain was A$32.6 × 106 (US$20.9 × 106). Conclusions: Our study is the first step towards a more comprehensive valuation of the societal contribution of sustainable shark fisheries. Implications: This novel information has a range of applications, from developing social and economic objectives in fisheries harvest strategies to empowering government agencies when making decisions on natural resource management. We calculated the social and economic contribution of the shark fishery operating in Western Australia, one of the world's few sustainable shark fisheries. We found substantial management-driven reductions in fishing effort and improvement in catch rates. This fishery provides considerable socio-economic returns to regional economies, with an average annual market value of A$32.6 × 106. [ABSTRACT FROM AUTHOR]

Sharks are an interesting group of vertebrates, as many species swim continuously to "ram" oxygen-rich seawater over their gills (ram ventilators), whereas other species "pump" seawater over their gills by manipulating buccal cavity volume while remaining motionless (buccal pumpers). This difference in respiratory physiology raises the question: What are the implications of these differences in lifestyle for circadian rhythms? We investigated the diel activity patterns of 5 species of sharks, including 3 ram ventilating species: the school shark (Galeorhinus galeus), the spotted estuary smooth-hound (Mustelus lenticulatus), and the spiny dogfish (Squalus acanthias); and 2 buccal pumping species: the Port Jackson (Heterodontus portusjacksoni) and draughtsboard (Cephaloscyllium isabellum) sharks. We measured the amount, duration, and distance traveled while swimming over multiple days under a 12:12 light:dark light regime for all species and used modified light regimes for species with a clear diel rhythm in activity. We identified a surprising diversity of activity rhythms. The school shark and smooth-hound swam continuously; however, whereas the school shark swam at the same speed and covered the same distance during the day and night, the smooth-hound swam slower at night and traversed a shorter distance. A similar pattern was observed in the spiny dogfish, although this shark swam less overall. Both the Port Jackson and draughtsboard sharks showed a marked nocturnal preference for swimming. This pattern was muted and disrupted during constant light and constant dark regimes, although circadian organization of this pattern was maintained under certain conditions. The consequences of these patterns for other biological processes, such as sleep, remain unclear. Nonetheless, these 5 species demonstrate remarkable diversity within the activity rhythms of sharks. [ABSTRACT FROM AUTHOR]

One-third of all elasmobranchs (sharks and rays) are threatened with extinction. Euryhaline and estuarine generalist elasmobranchs are a group of 29 species that occupy non-marine environments during particular life-stages. These species are poorly known and disproportionately threatened, with 72.4% at risk of extinction or Data Deficient. A detailed knowledge of a species' life history characteristics, movement ecology, habitat use, and population structure are required for the implementation of appropriate management and conservation measures. To date, research on euryhaline and estuarine species has lagged behind marine species. Here, a literature review and gap analysis of the euryhaline and estuarine species was conducted to identify gaps in 14 key parameters required for management. Of the 29 species, only the Bull Shark (Carcharhinus leucas) and the Largetooth Sawfish (Pristis pristis) had detailed information on a majority of parameters assessed. Nine species lack information on most parameters, while the Broadnose Wedgefish (Rhynchobatus springeri) lacks information on all but one of the parameters investigated. There is a high level of understanding of age- and size-at-maturity, size-at-birth, and growth for only five species, while nine species have estimates of natural mortality. Comprehensive reproductive biology data is unavailable for six species. Both short- and long-term movement ecology is well-understood for only two species, and habitat use for six species. Population structure has been studied in only eight species. Data on key life history parameters, population structure, and habitat requirements of the euryhaline and estuarine elasmobranchs are urgently required to develop appropriate management strategies and to secure populations. [ABSTRACT FROM AUTHOR]

Identifying sex-linked markers from genomic data has both theoretical and applied importance, especially in conservation. Yet, few methods and tools exist to detect such markers from Restriction-site-Associated DNA sequencing reads and even fewer tools can identify sex-linked markers from existing genotyped data. Here, we describe a new R function that can identify sex-linked markers in species with partially non-recombining sex chromosomes. We test the accuracy and speed of our function with an example dataset from a species of conservation concern, the White Shark, Carcharodon carcharias. We further compare our method against other approaches and find that our method detects more sex-linked markers that can be reliably mapped to reference genomes. Overall, we provide a conservation and fisheries-relevant tool that can reliably and efficiently assign sex from genetic data in species with a heterogametic sex and we demonstrate its utility by developing a sex-identification PCR test for White Sharks. [ABSTRACT FROM AUTHOR]

Citizen science online platforms are increasingly making important sources of biological information available at the click of a button, allowing the interaction of volunteers and scientists to report and identify the world's diversity. In this work, we combined the data available in citizen science platforms (iNaturalist and GelAvista) and the effort and collaboration of a diverse team of scuba-divers, scientists, and underwater photographers to report for the first time the presence of the stauromedusa Lipkea (Cnidaria: Staurozoa) in Portugal. Based on DNA (COI and 16S), we identified the species as Lipkearuspoliana. However, the marginal lappets of some Portuguese specimens are similar to those of Lipkeasturdzii, a species described based on a single specimen in 1893 and never reported again. These results suggest that L.sturdzii is a synonym of L.ruspoliana, although further taxon and habitat sampling for genetic studies and investigations of intraspecific morphological variation are necessary. In addition, we provided data on species ecology, reviewed the records of Staurozoa from Portugal, and mapped the world geographic distribution of Lipkea. Staurozoa is a cryptic group of cnidarians, and Lipkea seems to be a particularly rare genus. Citizen science has proved to be a valuable contribution to studies on the group, enabling biological discussions that otherwise would be more challenging. [ABSTRACT FROM AUTHOR]

Data collection by citizen scientists is emerging as an important practice for biodiversity detection, mapping, and compilation of big data in open online platforms such as iNaturalist, acting as a source of biodiversity discovery. However, the validation of species identification is a central issue for the scientific use of these data. Here we compared the list of marine species in the Western Atlantic Ocean obtained in iNaturalist with that generated from scientific collections to understand whether there are taxonomic bias favoring some types of organisms, and to understand the amount of trustful information at the species level in iNaturalist. We also present the first bioblitz results of marine biodiversity in Brazil, an iNaturalist Citizen Science campaign advertised by social media, as a case study. We found that marine taxa with higher richness were well represented in iNaturalist (Arthropoda, Mollusca and Chordata), nonetheless Annelida, Bryozoa, Nematoda, Nemertea, Platyhelminthes, Porifera, Chlorophyta, and Rhodophyta were under-represented. Taxa with small, cryptic, parasitic and/or sessile organisms were poorly represented. According to the methods applied in this study, we showed that 72% of the records are probably well identified, except for Bryozoa and Platyhelminthes. Brazilian marine records in iNaturalist add up to only 1/30 of the total West Atlantic records analyzed but there was a steep increase from 2021 to 2022, as a possible contribution of our bioblitz campaign especially for Arthropoda, Echinodermata, and Annelida. We conclude that the record of marine biodiversity by citizen scientists is a valuable tool, but the engagement of taxonomists is strongly recommended to increase the correct identification of species. [ABSTRACT FROM AUTHOR]

The nocturnal feeding behavior and zoogeographical habitat of cookiecutter sharks Isistius brasiliensis and Isistius plutodus (Isistius spp.) greatly reduces interaction of this species with live humans. Attacks on live humans are exceedingly rare with 7 cases reported worldwide, 6 of them in Hawaiʻi, and 5 of these occuring among channel swimmers. Published research suggests that periods of bright moonlight may increase Isistius spp. contact with live humans and does not otherwise identify significant trends or risk factors. Yet 5 of the 6 Isistius spp. bites on live humans in Hawaiʻian waters occurred with the moon set and after nautical twilight end and before nautical twilight start. From 1961–2023 in Hawaiʻi, 129 successful solo channel crosses and 5 Isistius spp. related injuries in the habitat of cookiecutter sharks were analyzed across two groups: one where both the moon and sun were set (dark group) and one where the moon and/or sun was in the sky (light group). There was a significant difference for swimmers bitten by Isistius spp. in the dark 4 (12%) versus light groups 1 (1%), p = 0.012, RR 12.6 (95% confidence interval: 1.5–108.9). Swim start time and year was also significant (Pearson correlation 0.566, p <0.001). Swimmer gender and use of shark deterrent devices and artificial illumination were not significant. The growing popularity of channel swimming in Hawaiʻi and swim start times have contributed to an increasing likelihood of live human and Isistius spp. contact and a moonless night sky is a significant risk factor for this interaction. [ABSTRACT FROM AUTHOR]

In the seascape, species migrate between ecosystems to complete their life cycles, and such ontogenetic migrations create functional connections between ecosystems. Nevertheless, the scarcity of information on patch distribution, species life history and ecology limits its application in Marine Protected Areas (MPA) management. We use a potential connectivity network approach to analyze how Haemulon flavolineatum might move through a complex and diverse seascape by simulating part of its life cycle migrations among three ecosystems (reef, mangrove, and seagrass) in the MPA of Bahía Portete-Kaurrele (BPK), Colombia. We used available ecosystem cover maps to conduct habitat fragmentation analyses and evaluate structural connectivity in BPK using eight indices that describe ecosystem patches and how they are related. With published information on the H. flavolineatum home range and its ontogenetic migration distances, we estimated the potential functional connectivity (CONNECT and migration distances) between ecosystems by building bipartite graphs. The benthic habitat configuration of the BPK could allow Haemulon flavolineatum to complete at least two stages of its life cycle (stage 5 mangroves to reefs being more likely than stage 4 seagrass to mangroves). Ontogenetic migrations is possible since, patches of different ecosystems were highly intermixed (76%) rather than grouped (58%); reefs showed higher values of structural indices (patch area, largest patch, shape complexity, functional links) than mangrove (shortest distance to the nearest neighbor) and seagrass (representativeness); and juveniles migrate from mangroves to reef patches along the bay, but they could be isolated by distance when moving from particular seagrass to mangrove patches. Our methodological approach, which integrates ecological information (evidence-based ranges of species migration distances between habitat patches) and the seascape (spatial configuration of habitat patches and fragmentation) is novel for a marine fish species with ontogenetic migration to search for the likelihood of completing its life cycle stages. We discuss the need for ecological information on French grunts and the need to validate future models and scenarios. [ABSTRACT FROM AUTHOR]

The brown meagre (Sciaena umbra) is an endangered species, which requires specific protection measures to ensure its conservation. These measures need to be informed by high-quality scientific knowledge on their space use patterns. Here, we used acoustic telemetry to assess its seasonal movement patterns and habitat use within a marine protected area (MPA). Our results suggested that S. umbra is a highly sedentary species (home range < 1.0 km2) and, therefore, the MPA is extensive enough to protect the local population. Their population was discretely distributed in two main areas within the MPA, which was likely a result of habitat segregation and density-dependent movements. The temporal variability of their movements further uncovered when and where spawning occurs (mainly, but probably not only, in the fully protected area in June) and indicated that spillover of this species is limited but still possible. Overall, we highlight the importance of MPAs in the recovery of S. umbra, we advocate the need to perpetuate the current national fishing bans and extend it to other countries in the Mediterranean region, and we emphasize that considering the fine-scale movements of S. umbra in future management actions is key to achieving a successful recovery of their populations. [ABSTRACT FROM AUTHOR]

Step-selection models are widely used to study animals' fine-scale habitat selection based on movement data. Resource preferences and movement patterns, however, often depend on the animal's unobserved behavioral states, such as resting or foraging. As this is ignored in standard (integrated) step-selection analyses (SSA, iSSA), different approaches have emerged to account for such states in the analysis. The performance of these approaches and the consequences of ignoring the states in step-selection analysis, however, have rarely been quantified. We evaluate the recent idea of combining iSSAs with hidden Markov models (HMMs), which allows for a joint estimation of the unobserved behavioral states and the associated state-dependent habitat selection. Besides theoretical considerations, we use an extensive simulation study and a case study on fine-scale interactions of simultaneously tracked bank voles (Myodes glareolus) to compare this HMM-iSSA empirically to both the standard and a widely used classification-based iSSA (i.e., a two-step approach based on a separate prior state classification). Moreover, to facilitate its use, we implemented the basic HMM-iSSA approach in the R package HMMiSSA available on GitHub. [ABSTRACT FROM AUTHOR]

Acoustic telemetry provides valuable insights into behavioural patterns of aquatic animals such as downstream migrating European eels (Anguilla anguilla), so called silver eels. The behaviour of silver eels during the migration is known to be influenced by environmental factors, yet so is the performance of acoustic telemetry networks. This study quantifies the impact of these environmental factors on both, migration behaviour and receiver performance to determine possible limiting conditions for detecting tagged eels in tidal areas. A dominance analysis of the selected models describing migration speed, activity and receiver performance was conducted following 234 silver eels that were tagged with acoustic transmitters and observed by a receiver network in the Ems River during two subsequent migration seasons. The results suggest a passive locomotion of silver eels during their downstream migration by taking advantage of selective tidal stream transport (STST). It is further shown that water temperature, salinity, turbidity, precipitation, and especially current velocity were major parameters influencing migration activity and speed. At the same time, analyses of the detection probability of tagged eels under varying environmental conditions indicated a decreased receiver performance during increased current velocities, meaning that high migration activity and -speed coincides with reduced detection probability. Consequently, there is a risk that particularly during phases of increased activity, migration activity may be underestimated due to reduced acoustic telemetry performance. To avoid bias in telemetry studies, it is, therefore, crucial to conduct range tests and adjust the receiver placement in areas and conditions of high current velocities. [ABSTRACT FROM AUTHOR]

Background: The provision of habitat for fishery species in estuaries is highly valued and represents one of the most challenging ecosystem service values to quantify. However, quantifying this value is challenging due to complex relationships between habitat change, ecological processes, and environmental variations. This study aims to estimate estuarine habitat degradation and its impact on the reproduction process of the crab Eriocheir sinensis by characterizing the changes in breeding habitat and investigating relationships between the species and its habitat in the Yangtze River Estuary. Methods: A species distribution model recently developed was applied to estimate the extent and quality of breeding habitat changes from 2014–2021. The intrinsic (physiological) and external (structural) reproductive attributes of the breeding process were measured to assess the effects of habitat change. The relationships among habitat change, reproductive attributes and environmental factors were analyzed to understand the underlying driving forces of habitat degradation for breeding process by multivariate statistical analysis. Results: About 34.24% of essential habitat was lost, mainly in highly suitable areas due to reclamation and waterway construction. Habitat degradation significantly affects female distribution and their reproductive processes, particularly gonad development during the pre-reproductive period and fecundity during the reproductive period, without altering population structure. These results indicated that the main ecological function served by the highly suitable breeding ground was the provision for development of gonad and improvement of fecundity. Increases of salinity and turbidity, caused by hydrodynamic changes from large-scale waterway construction, were identified as the environmental determinants contributing to cumulative habitat degradation. These influences ultimately led to a decrease in the fecundity of E. sinensis. Conclusions: Our research sheds light on the quantification of habitat degradation in the Yangtze River Estuary and its implications for the reproduction process of E. sinensis, which can serve as a foundation for assessing and quantifying the ecosystem service values provided by these breeding grounds. This information is valuable for policymakers and resource managers in making informed decisions regarding habitat conservation and the sustainable utilization of fishery resources. [ABSTRACT FROM AUTHOR]

The fisheries history of the Giant Sea Bass, Stereolepis gigas (Telostei: Polyprionidae), is closely linked to its spatial ecology. Its overharvest is directly associated with formation of spatially distinct spawning aggregations during summer, while its subsequent recovery is hypothesized to be the result of spatially explicit gear restrictions. Understanding the spatial ecology of Giant Sea Bass is a key part of efforts to assess contemporary threats such as commercial harvest and incidental catch by recreational fisheries. In this study, we used acoustic telemetry to characterize Giant Sea Bass space use in the La Jolla kelp forest using an acoustic array that encompasses two marine protected areas (MPAs) and heavily trafficked recreational fishing grounds. Five of the seven fish we tagged remained in the La Jolla array for at least 6 months. Two fish were resident across multiple years, with one fish consistently detected for 4 years. Only one fish was detected in the broader network of regional acoustic receivers, moving north approximately 8 km to Del Mar. Most tagged fish had home ranges and core use areas indicating they spend considerable time outside MPAs, particularly in areas with high recreational fishing activity. During spawning season we detected fish less frequently in the La Jolla array and recorded higher movement rates. While the current MPA network in La Jolla by no means offers complete protection to this fish, it does appear to support long-term persistence of some individuals in a region of exceptionally high recreational fishing pressure. [ABSTRACT FROM AUTHOR]

Introduction: Determining the exact weight of children is a challenging task during emergency situations. Current guidelines recommend the use of length-based weight-estimating tapes. However, healthcare providers must either always carry the tapes or take time to locate them. Moreover, they may not know how to use them. To address these issues, we developed an augmented reality smartphone application for length-based weight estimation called the Paediatric Augmented Reality Scale (PARS). We evaluated its performance and compared it to that of the Broselow tape (BT) and Paediatric Advanced Weight Prediction in the Emergency Room extra-long and extra-large (PAWPER-XL) tape methods. Method: A prospective, single-blinded cross-sectional study was conducted with children aged 1 month to 12 years who visited the emergency department of the tertiary university hospital in Bucheon, South Korea between July 2021 and February 2022. This study aimed to evaluate the measurement agreement and performance of 3 methods: BT, PAWPER-XL and PARS. Results: In all, 1090 participants were enrolled, and 639 (58.6%) were male. The mean age of the participants was 4.1 ± 2.8 years, with a mean height of 102.7 ± 21.7 cm and mean weight of 18.8 ± 9.5 kg. Compared to BT and PAWPER-XL, PARS exhibited lower mean absolute percentage error (9.60%) and root mean square percentage error (3.02%). PARS achieved a higher proportion of weights estimated within 10% of the actual weight (63.21%), outperforming BT (57.25%) and PAWPER-XL (62.47%). The intraclass correlation coefficients for the actual and estimated weights of BT, PAWPER-XL and PARS were 0.952, 0.969 and 0.973, respectively (P<0.001). Conclusion: PARS exhibited a modestly better performance than BT and PAWPER-XL in estimating body weight. PARS-estimated body weights correlated fairly accurately with the actual body weights. PARS holds potential utility in paediatric emergencies. [ABSTRACT FROM AUTHOR]

N. norvegicus supports one of the most commercially-important fisheries in the Mediterranean, and there is considerable interest in developing non-invasive sampling stock assessment methods. Currently, stock assessments are conducted via trawling or by UnderWater TeleVision (UWTV) surveys with limited capacity to provide direct population data due to the burrowing behavior of the species. Here, we used acoustic telemetry to characterize the burrow emergence and movement patterns of N. norvegicus in relation to internal tides and inertial currents in deep-sea habitats of the northwestern Mediterranean. We deployed acoustic tags on 25 adults between May and June 2019, and collected up to 4 months of detection data from each tag. Tagged lobsters spent approximately 12% of their time in door-keeping (i.e., detections at burrow entrance with no displacements) but differences existed among the different behavioral rhythms identified. We observed that mixed day-night, tidal and inertial rhythms in field settings were similar to those observed in laboratory tests. The presence of mixed day-night and tidal periodicity poses the question of why N. norvegicus exhibits flexible responses to environmental cues other than photoperiod. It is possible that tidal regulation of locomotor activity could reduce energy expenditure in relation to hydrodynamic drag. Inertial periodicity occurs in animals with no clear burrowing-oriented activity (always present on the seabed). Possibly, inertial-related movements are the result of a disruption of the biological clock. Our results are discussed in the context of how burrow emergence rhythms may bias UWTV surveys and how novel in situ monitoring approaches address these biases. [ABSTRACT FROM AUTHOR]

Individual fish movement patterns and behaviors influence population-level traits, and are important for understanding their ecology and evolution. Understanding these behaviors is key for managing and conserving migratory animal populations, including Atlantic tarpon (Megalops atlanticus), that support an economically important recreational fishery. Using acoustic telemetry, we tracked individual movement patterns of M. atlanticus inhabiting the eastern Gulf of Mexico and the southeast coast of the US over successive years. Net-squared displacement models revealed considerable individual-level variation in movement patterns with high individual-level repeatability in the timing of migrations and migratory pathways. Although distinct migratory subgroups existed, M. atlanticus generally migrate northward in the spring and summer to putative foraging grounds and remain in these areas for, on average, four months and then migrate southward in the fall. Subadult M. atlanticus exhibited similar migratory patterns as adults, while large juveniles exhibited either resident or nomadic behaviors. For migratory individuals, fish size did not influence movement patterns. Given that distinct migratory subgroups seasonally mixed in southern Florida for spawning activity, our study indicates that M. atlanticus along the eastern Gulf of Mexico and southeastern coast of the US should be considered a single interconnected stock. With that in mind, using M. atlanticus angler and guide knowledge, we assessed the vulnerability of M. atlanticus to potential threats across their range and along migratory pathways. Collectively, the far-ranging nature of M. atlanticus and their diversity in movement patterns highlights the need for more uniform and cohesive management and conservation efforts. [ABSTRACT FROM AUTHOR]

Nesting events of loggerhead sea turtles (Caretta caretta) are on the rise in the Western Mediterranean Sea, far from their usual nesting areas in the Mediterranean and Atlantic basins. The study of dispersal behavior toward potential developmental areas of loggerhead post-hatchlings from this new nesting area is crucial to comprehend this colonization process and determining grounded conservation strategies. To fill this gap, we investigated, for the first time in the Mediterranean Sea, the dispersal strategies and habitat use based on data from 19 head-started loggerhead post-hatchlings released from the Spanish Mediterranean coast and satellite-tracked between 2016 and 2018. Turtles dispersed over large areas and showed active swimming phases, as they frequently dispersed against sea currents. Dispersal routes varied for each individual, although they consistently dispersed south-eastwards, especially during the coldest periods. Several post-hatchlings traveled through the Sicilian Channel to reach deep and warmer areas in the eastern Mediterranean basin. The most year-round suitable areas corresponded to the Ionian and Levantine Seas, which correspond with those found in their traditional nesting areas. Therefore, conservation measures focused on this stage should be taken in the path toward and these developmental areas. [ABSTRACT FROM AUTHOR]

Animal aggregation, particularly in large-bodied species, is both a fascinating and intriguing phenomenon. Here we analyzed the overwintering behavior of the European catfish, Silurus glanis Linnaeus, 1758, the largest freshwater fish in Europe. By tracking 47 subadults and adults in a shallow lake in southeastern France, we reported a consistent aggregative behavior across four successive winters. By implementing time series analysis and Cox proportional hazard models, we investigated the dynamics of these aggregations (formation, stability, dislocation), and the factors that govern it, whether external (temperature, time of the day) or specific to the fish (size, key individuals). These aggregations lasted 1.5–2 months and mainly took place in a single small 4 m-deep area whose environmental conditions (temperature, oxygen, substrate) did not differ from other parts of the lake. In some periods during winter, all tagged fish were aggregated, which suggests that a large proportion of the lake population gathered there. Low temperatures (below 9 °C) triggered the formation of aggregations. They became more stable with decreasing temperatures, while individuals more frequently left the aggregation, preferentially at dusk and at night, when temperatures increased. The largest individuals swam more frequently back and forth to the aggregation. Irrespective of their size, some individuals consistently arrived earlier in the aggregation in winter and left later. This predictable seasonal grouping of individuals and, more generally, the knowledge provided by such studies on how species use space have important operational value and are useful for species conservation as well as for species control. [ABSTRACT FROM AUTHOR]

Understanding how reef-associated sharks use coastal waters through their ontogeny is important for their effective conservation and management. This study used the horizontal movements of acoustically tagged Caribbean reef sharks (Carcharhinus perezi) to examine their use of coastal space around the Cayman Islands between 2009 and 2019. A total of 39 (59.1%) tagged sharks (male = 22, female = 17, immature = 18, mature = 21) were detected on the islands wide network of acoustic receivers. The detection data were used to calculate values of Residency Index (RI), Site-Fidelity Index (SFI) and minimum linear displacement (MLD), as well as for network analysis of individual shark movements to test for differences between demographics, seasons, and diel periods. Sharks were detected for up to 1,598 days post-tagging and some individuals showed resident behaviour but the majority of tagged individuals appear to have been one-off or only occasional transient visitors to the area. Generally, individuals showed strong site-fidelity to different areas displaying linear home ranges of < 20 km. The evidence indicates that there was no pattern of diel behaviour. Tagged sharks generally showed increased movements within and between islands during the summer (April–September), which may be related to breeding activity. Some individuals even made occasional excursions across 110 km of open water > 2,000 m deep between Grand Cayman and Little Cayman. One mature female shark showed a displacement of 148.21 km, the greatest distance reported for this species. The data shows that the distances over which some sharks moved, greatly exceeded the extent of any one of the islands' marine protected areas indicating that this species may be more mobile and dispersive than previously thought. This study provides support for the blanket protection to all sharks throughout Cayman waters, which was incorporated within the National Conservation Act in 2015. [ABSTRACT FROM AUTHOR]

Studies involving acoustic telemetry typically use stationary acoustic receivers arranged in an array or grid. Unmanned surface vehicle (USV)-based mobile receivers offer advantages over the latter approach: the USV can be programmed to autonomously carry a receiver to and from target locations, more readily adapting to a survey's spatial scope and scale. This work examines the acoustic detection performance of a low-cost USV developed as a flexible sensing platform. The USV was fitted with an acoustic receiver and operated over multiple waypoints set at increasing distances from the transmitter in two modes: drifting and station-keeping. While drifting, the USV was allowed to drift from the waypoint; while station-keeping, the USV used its thruster to hold position. Detection performance of the USV was similar to that of stationary receivers while drifting, but significantly worse while station-keeping. Noise from the USV thruster was hypothesized as a potential cause of poor detection performance during station-keeping. Detection performance varied with the depth of the tethered receiver such that detection range was greater during the deepest (4.6 m) trials than during shallower (1.1 and 2.9 m) trials. These results provide insight and guidance on how a USV can be best used for acoustic telemetry, namely, navigating to a planned waypoint, drifting and lowering the receiver to a desired depth for listening, and then navigating to the next waypoint. [ABSTRACT FROM AUTHOR]

The exploitation of sharks and the degradation of their habitats elevate the urgency to understand the factors that influence offspring survival and ultimately shark reproductive success. We monitored and sampled blacktip reef sharks (Carcharhinus melanopterus) in nursery habitats of Moorea Island (French Polynesia), to improve knowledge on shark reproductive behavior and biology. We sampled fin clips and morphometrics from 230 young-of-the-year sharks and used microsatellite DNA markers to process parentage analysis to study the reproductive philopatric behavior in female sharks and the matrotrophy within litters. These traits are driving the success of the local replenishment influencing selection through birth site and maternal reserves transmitted to pups. Parentage analysis revealed that some female sharks changed their parturition areas (inter-seasonally) while other female sharks came back to the same site for parturition, providing evidence for a plastic philopatric behavior. Morphometrics showed that there was no significant relationship between body condition indices and nursery locations. However, similarities and differences in body condition were observed between individuals sharing the same mother, indicating that resource allocation within some shark litters might be unbalanced. Our findings further our understanding of the reproductive biology and behavior that shape shark populations with the aim to introduce these parameters into future conservation strategies. [ABSTRACT FROM AUTHOR]

Insight into the detection range of acoustic telemetry systems is crucial for both sampling design and data interpretation. The detection range is highly dependent on the environmental conditions and can consequently be substantially different among aquatic systems. Also within systems, temporal variability can be significant. The number of studies to assess the detection range in different systems has been growing, though there remains a knowledge gap in estuarine habitats. In this study, a 2-month experimental set-up was used to assess the detection range variability and affecting environmental factors of an estuary. Given the expected complex interplay of different factors and the difficulties it entails for interpretation, a structural equation modelling (pSEM) approach is proposed. The detection range of this estuarine study was relatively low and variable (average 50% detectability of 106 m and ranging between 72 and 229 m) compared to studies of riverine and marine systems. The structural equation models revealed a clear, yet complex, tidal pattern in detection range variability which was mainly affected by water speed (via ambient noise and tilt of the receivers), water depth and wind speed. The negative effect of ambient noise and positive effect of water depth became more pronounced at larger distances. Ambient noise was not only affected by water speed, but also by water depth, precipitation, tilt angle and wind speed. Although the tilt was affected by water speed, water depth and wind speed, most of the variability in tilt could be traced back to the receiver locations. Similarly, the receiver locations seemed to explain a considerable portion of the detection range variability. Retrospective power analyses indicated that for most factors only a minor gain in explanatory power was achieved after more than two days of data collecting. Redirecting some of the sampling effort towards more spatially extensive measurements seems to be a relevant manner to improve the insights in the performance of telemetry systems in estuarine environments. Since the low and variable detection range in estuaries can seriously hamper ecological inferences, range tests with sound sampling designs and appropriate modelling techniques are paramount. [ABSTRACT FROM AUTHOR]

The nursery habitats of the broadnose sevengill shark Notorynchus cepedianus (Péron, 1807) remain largely unknown. The identification of these critical habitats is important for the conservation of these top-down regulator species and general coastal ecosystem dynamics. We investigated the role of the San Antonio cape (Argentina) as a nursery habitat for N. cepedianus and tested the hypothesis that physical conditions (turbidity, sea surface temperature) are more important than prey abundance in the habitat use by young-of-the-year (YOY). We used the presence, relative abundance, and size structure of YOY from a small-scale gillnet fishery (2008–2014) to assess the intra- and inter-annual persistence in habitat use. The results indicated intra- and inter-annual persistence in estuarine habitat use, and comparisons with previous studies suggested that YOYs were more commonly encountered in San Antonio cape than in other suitable areas. Finally, the YOYs' use of the area may be explained by a combination of the spatial–temporal variation in turbidity conditions and food abundance. These results suggested San Antonio cape as a nursery habitat for N. cepedianus YOYs and highlighted the importance of understanding key biophysical effects that regulate the use, movement, and residency of N. cepedianus in their nursery habitats. [ABSTRACT FROM AUTHOR]

Many ray species are threatened with extinction, and so understanding their movement and habitat use is vital for developing effective management and conservation efforts. Globally, rays are known to rely on estuarine habitats, but estuary use by rays has not yet been investigated in South Africa. Thirty-three diamond rays Gymnura natalensis and 25 bull rays Aetomylaeus bovinus, both species anecdotally recorded to occur in estuaries, were acoustically tagged. Individuals were tracked using a nation-wide network of receivers in South Africa, the Acoustic Tracking Array Platform (ATAP), that has acoustic receivers in both marine and estuarine environments. Only six rays (4 diamond and 2 bull rays) were recorded using estuaries, but they displayed seasonal philopatry, returning to specific estuaries during spring to autumn months (September to May) for up to 6 consecutive years. Due to a number of rays entering the Breede Estuary, the fine-scale habitat use in this ecosystem was investigated. Marine-estuarine connectivity was significantly influenced by marine temperatures. Additionally, presence in the upper parts of the Breede Estuary (up to 17 km from the mouth) was influenced by temperature, tides and time of day. Findings suggest estuaries are an important, and previously overlooked, habitat type for a portion of the diamond and bull ray populations on the south coast of South Africa, which has management and conservation implications. [ABSTRACT FROM AUTHOR]

Context. Giant guitarfish (Family: Glaucostegidae) and wedgefish (Family: Rhinidae) (Critically Endangered, IUCN Red List and CITES Appendix II) are highly exploited throughout their distribution because of their highly valued fins in the international market. Both are commonly caught as bycatch or secondary valuable catch in the Java Sea, including in Karimunjawa National Park, Central Java, Indonesia. Aims. Assess the presence and relative abundance of giant guitarfish and wedgefish species in Karimunjawa National Park and adjacent waters. Methods. Data were collected using baited remote underwater video (BRUV) surveys across 40 sites, covering multiple zonation areas and depth ranges. All species were identified to the species level and their relative abundance was tested with one-way PERMANOVA based on sites, zonation areas and depths. Key results. Two target species, Glaucostegus typus and Rhynchobatus australiae, were present in the study area with a maximum number of 3 and 6 and relative abundance of 0.0048 and 0.0096 respectively, over 477 BRUVs and 623.9 h of videos. Their presence during the study was not affected by sites, zonations or depth. Implications. The presence and relative abundance of both G. typus and R. australiae were low, which may bea result of decades of overfishing, and have provided the first information to the urgency of managing the species in the areas. [ABSTRACT FROM AUTHOR]

Context. Nursery areas provide refuge from predators, rich foraging grounds, and physical conditions conducive to growth and development of juvenile inhabitants. Specifically, the Mississippi Sound in the northern Gulf of Mexico is likely a nursery ground for multiple large and small coastal sharks. Aims and methods. Using over a decade of shark survey catch data, we employed habitat modelling approaches to identify preferred environmental conditions and spatial distribution, and quantify core habitat overlap within the Mississippi Sound for young-of-year (YOY), juvenile and adult life stages of four coastal shark species. Results. YOY Atlantic sharpnose (Rhizoprionodon terraenovae), blacktip (Carcharhinus limbatus) and finetooth (Carcharhinus isodon) sharks showed a preference for a combination of shallow, warm, low salinity, low dissolved oxygen and turbid waters. Corresponding to shared environmental preferences, spatial distributions of YOY sharks showed a high degree of overlap, particularly in the northern portion of the Mississippi Sound where few adult sharks were observed, suggesting that these life stages partition themselves to avoid predation. Conclusion and implications. With a continued rise in US coastal shark populations, we hope this study can help further refine essential fish habitat for these coastal species and provide a framework analysis that can be used to understand habitat partitioning in other regions. [ABSTRACT FROM AUTHOR]