Figure - available from: Frontiers in Marine Science
This content is subject to copyright.
One minute pseudo-tracks of tiger shark interactions with Chinamanfish (Symphorus nematophorus). Track line is colored by tailbeat frequency (Hz). Red dashed square indicates where the fish was observed in the video field of view (displayed in screenshots to the right of the pseudo-track). X and Y-axes represent arbitrary units of latitude and longitude created by magnetometer and accelerometer data whilst a constant speed is assumed. (A) Example of an interaction where the tailbeat of the shark slows upon encountering the fish. (B) Example of an interaction where the tailbeat of the shark quickens upon encountering the fish. As constant speed was used to estimate pseudo-tracks, we caution that speed changes throughout the sampling period by tagged sharks may slightly influence the shape of resulting pseudo-tracks.
Source publication
An understanding of the role that large marine predators play in structuring trophic flow and nutrient cycling in marine ecosystems requires knowledge of their fine-scale (m-km) movement behaviors. In this study, biologging tags were used to reveal new insights into the three-dimensional fine-scale movement ecology of tiger sharks (Galeocerdo cuvie...
Citations
... Pressure sensor data (Depth) and a maximum depth value of each hour of data (Depth_Max) were used to determine the depth use of sharks in different areas and times using the mask analysis in Ethographer. Vertical velocity (VV) was calculated using a 10-s running mean on depth use data and calculating the difference of successive periods using a 1-s interval (Andrzejaczek et al., 2018;Andrzejaczek, Gleiss, Lear, et al., 2019). These values were then converted to an absolute scale (VV_abs). ...
... Estimated pathways can be validated and adjusted using pitch, roll, and first location of SPOT transmissions post-release, yet may be subjected to significant error from environmental conditions (such as currents). As a result of these errors, dead reckoned paths are not a true representation of where movements took place but accurately predict the shape and angles of movement in three dimensions (Andrzejaczek, Gleiss, Lear, et al., 2019). Three separate time frames were selected, 1, 5, and 20 min, to account for finer (indicative of interactions with prey or habitat features, i.e., Jewell et al., 2019) and larger scale (indicative of residency periods or area-restricted search, i.e., Towner et al., 2016) changes in heading. ...
... At night, movements of sharks tagged at the Farallon Islands were away from the island group toward deeper waters, and at Año Nuevo they were away from the island rookery along the continental shelf. During the day, sharks were, in general, more active, engaged in more vertical movement, and swam in more tortuous paths (Figure 4), all of which have been linked to foraging behavior in other species of sharks where increased searching/encounter behavior is suggested by this type of locomotion (Andrzejaczek, Gleiss, Lear, et al., 2019;Gleiss et al., 2013;Lear et al., 2021). However, there were areas where crepuscular periods had similar patterns in locomotion, with sharks at the Farallon Islands and Aptos more active and tortuous at dawn and dusk, respectively. ...
An animal's movement is influenced by a plethora of internal and external factors, leading to individual‐ and habitat‐specific movement characteristics. This plasticity is thought to allow individuals to exploit diverse environments efficiently. We tested whether the movement characteristics of white sharks Carcharodon carcharias differ across ontogeny and among habitats along the coast of Central California. In doing so, we elucidate how changes in internal state (physiological changes coinciding with body size) and external environments (differing seascapes and/or diel phases) shape the movement of this globally distributed predator. Twenty‐one white sharks, from small juveniles to large adults, were equipped with motion‐sensitive biologging tags at four contrasting seascapes: two islands, a headland, and an inshore cove. From multisensor biologging data, 20 metrics characterizing movement (i.e., depth use, vertical velocities, activity, turning rates, and bursting events) were derived and subjected to multivariate analyses. Movement characteristics were most different across seascapes, followed by ontogeny and diel phase. Juvenile sharks, which were only encountered at the cove, displayed the most distinct movement characteristics. Sharks at this seascape remained close to the shore traveling over smaller areas, shallower depth ranges, and with lower levels of tail beat frequencies, when corrected for size, than sub‐adult and adult sharks tagged elsewhere. Distinct tortuous daytime versus linear nighttime horizontal movements were recorded from sharks at island seascapes but not from those at the headland or inshore cove. At the offshore islands, the linear nighttime swimming patterns coincided with repeated dives to and from deeper water. The availability of prey and access to deeper water are likely drivers of the differences in movement characteristics described, with varying demographics of pinniped prey found at the subadult and adult aggregation areas and juvenile sharks being piscivorous and their habitat neither adjacent to pinniped haul out areas nor deeper water. This study demonstrates plasticity in the movements of a top predator, which adapts its routine to suit the habitat it forages within.
... Walli et al. 2009, Queiroz et al. 2012, Vaudo et al. 2016 has been observed in a variety of fish moving over large distances; however, the relationships between transient and area-restricted search behavioral modes and vertical movement patterns have received limited investigation, although new technology is allowing such work to become increasingly common (e.g. Andrzejaczek et al. 2019, Logan et al. 2023. ...
Resources in the pelagic environment tend to be patchily distributed, often resulting in animals engaging in adaptive behaviors to maximize foraging success. While these behaviors have been examined in horizontal and vertical dimensions separately, there has been limited work integrating these functionally related movements in sharks. We investigated how vertical behaviors change in relation to horizontal movements in the pelagic, highly migratory, shortfin mako shark Isurus oxyrinchus . Data from 30 sharks (114 to 245 cm total length), double-tagged with Pop-up Archival and Transmitting (PAT) and Smart Position or Temperature Transmitting (SPOT) tags within the Southern California Bight were analyzed. We examined shark daytime depth distributions after their horizontal movements were first classified by water column thermal structure (thermal habitat), and into 1 of 2 behavioral modes (area-restricted search or transient) using a switching state-space model. Despite high inter- and intra-individual variability, thermal habitat and behavioral mode influenced depth distribution. Within thermal habitats, sharks spent similar amounts of time near the surface in both behavioral modes, although transient animals spent more time in deeper waters within some thermal habitats. Comparing among thermal habitats, sharks performing transient movements in warmer waters spent more time at depth. Sharks experienced an expansion of vertical habitat use when they switched to transient behaviors, possibly to search for prey, and the degree of habitat expansion may be influenced by temperature. These results suggest that in a 3-dimensional habitat, such as the pelagic environment, prey searching behaviors in the horizontal and vertical dimensions are linked.
... Tiger sharks were targeted using baited drumlines inside the reef lagoon at Ningaloo Reef, Western Australia in May 2016 for a tagging study (− 22.99 • 113.80 • E; see Andrzejaczek et al., 2019;Ryan et al., 2022). Drumlines were deployed between 7:00 am and 4:00 pm and equipped with a single 20/0 circle hook baited with fish scraps. ...
... The recovered data were analysed in Igor pro ver. 9.0 (Wavemetrics, Lake Oswego, OR, USA) with the package Ethographer (Sakamoto et al., 2009); detailed analytical methods are given in Andrzejaczek et al. (2019). Briefly, the gravitational component of acceleration was determined using a three second box smoothing window on the raw acceleration data (appropriate considering size of animal and dominant tailbeat frequency of ~0.78 Hz; Shepard et al., 2008). ...
... Though the exact moment of full stomach retraction is not possible to observe from the camera field of view, the tri-axial data suggests it occurred after approximately five of these burst behaviours. The acceleration signature of these upward bursts was similar to that of active foraging by tiger sharks recorded in a tagging study of the species at this locality (Andrzejaczek et al., 2019). As retraction obviously involved some increased energy expenditure, it might not be the case that retraction has no impacts on recovery in a situation where individuals have been through a longer period of capture with high energy output (e.g. in a sport fishery) or were hooked in a fishery where there was a long interval between capture and release of the animal. ...
... El uso de ACC tridimensionales se ha utilizado para el monitoreo de especies terrestres y acuáticas (Bidder et al. 2014) demostrando ser una potente forma de estudiar el comportamiento de animales en libertad, más aún en aquellos que son difíciles de observar (Foerster et al. 1999;Tsuda et al. 2006;Cooke 2008;Shepard et al. 2008;Wilson et al. 2008;Moreau et al. 2009;Williams et al. 2019). Los comportamientos identificados a partir de los datos del ACC se consideran una valiosa herramienta para estudiar la ecología del comportamiento, con múltiples objetivos, desde conocer sus patrones de movimiento (Nathan et al. 2008), la selección del hábitat y el uso de recursos (Johnson 1980;Kie et al. 2010;Andrzejaczek et al. 2019), detectar la aparición y la intensidad del comportamiento (Fehlmann et al. 2017;Chakravarty et al. 2020) e incluso para saber si un individuo se encuentra activo o inactivo (Gervasi et al. 2006;Whitney et al. 2007), de manera que se puedan identificar eventos de mortalidad (Kendall y Virani 2012;Fabrizio et al. 2019). ...
Los dispositivos de localización que incorporan tecnologías de Sistema de Posicionamiento Global (GPS) y acelerómetro (ACC), han supuesto un avance muy importante en el estudio de la ecología animal. Utilizando datos de 53 avutardas hubaras (Chlamydotis undulata fuertaventurae) marcadas con emisores GSM/GPRS durante el periodo 2017-2022 en las islas de Lanzarote, Fuerteventura y La Graciosa, describimos cómo es posible identificar y clasificar distintas pautas de comportamiento a través del software AcceleRater y utilizar esos datos para interpretar su ecología espacial. Mediante este software se determinó que el mejor modelo que clasifica los comportamientos de las hubaras es el conocido como Núcleo de Función de Base Radial/Máquinas de Vectores de Apoyo (RBF SVM), que ofrece un porcentaje de precisión del 92.95 %, permitiendo identificar siete tipos de comportamientos (carrera de exhibición, vocalización, movimiento precópula, vuelo, alimentación, descanso y vigilancia), de los diez comportamientos evaluados. Además, la asociación del patrón del ACC con las localizaciones GPS permite identificar los lugares concretos en los que se producen las exhibiciones, la nidificación, la alimentación y el descanso de los individuos marcados. El presente estudio evidencia cómo los avances tecnológicos pueden ofrecer indudables ventajas para conocer la ecología espacial de una especie a nivel individual, lo que supone un avance notable respecto a resultados poblacionales, más aún en aquellos con posibilidades de observación directa limitadas. Concluimos que los datos que se obtienen con estas tecnologías son de gran valor en investigación, y pueden ser clave para poder mejorar la gestión y conservación de las especies amenazadas.
... Knowledge of the physiological ecology of large pelagic fishes is particularly important for revealing mechanisms that underpin habitat suitability, species distributions and ecological functioning (Bernal et al., 2010), information which can inform the conservation of threatened populations (McKenzie et al., 2016;Vedor et al., 2021). For example, behaviours and activity levels occurring at fine spatio-temporal scales are likely to be key drivers of trophic interactions, which will affect habitat selection and thereby distributions (Andrzejaczek et al., 2019;Bowlby et al., 2022), ultimately driving spatial overlap with anthropogenic activities such as fishing (Queiroz et al., 2016;Queiroz et al., 2019;Queiroz et al., 2021). Nonetheless, due to the inherent difficulties in studying large animals in open-ocean environments, data on the finescale behaviours and energetics of apex predators such as sharks are often lacking (Lawson et al., 2019;McKenzie et al., 2016;Payne et al., 2015;Sims, 2003). ...
... The incorporation of tri-axial accelerometers into bio-logging systems allows for measurements of behavioural metrics down to subsecond scale (>100 Hz) (Cade et al., 2021;Fontes et al., 2022). These systems have been applied to multiple aspects of shark ecology, providing insights into predator-prey interactions (Andrzejaczek et al., 2019;Watanabe et al., 2019a), swimming kinematics (Nakamura et al., 2011;Payne et al., 2016;Watanabe et al., 2019b) and mating behaviours (Whitney et al., 2010). Accelerometry-derived metrics, such as dynamic body accelerations, may also serve as proxies for energy expenditure Wilson et al., 2020). ...
The shortfin mako shark is a large‐bodied pursuit predator thought to be capable of the highest swimming speeds of any elasmobranch and potentially one of the highest energetic demands of any marine fish. Nonetheless, few direct speed measurements have been reported for this species. Here, animal‐borne bio‐loggers attached to two mako sharks were used to provide direct measurements of swimming speeds, kinematics and thermal physiology. Mean sustained (cruising) speed was 0.90 m s⁻¹ (±0.07 s.d.) with a mean tail‐beat frequency (TBF) of 0.51 Hz (±0.16 s.d.). The maximum burst speed recorded was 5.02 m s⁻¹ (TBFmax = 3.65 Hz) from a 2 m long female. Burst swimming was sustained for 14 s (mean speed = 2.38 m s⁻¹), leading to a 0.24°C increase in white muscle temperature in the 12.5 min after the burst. Routine field metabolic rate was estimated at 185.2 mg O2 kg⁻¹ h⁻¹ (at 18°C ambient temperature). Gliding behaviour (zero TBF) was more frequently observed after periods of high activity, especially after capture when internal (white muscle) temperature approached 21°C (ambient temperature: 18.3°C), indicating gliding probably functions as an energy recovery mechanism and limits further metabolic heat production. The results show shortfin mako sharks generally cruise at speeds similar to other endothermic fish – but faster than ectothermic sharks – with the maximum recorded burst speed being among the highest so far directly measured among sharks, tunas and billfishes. This newly recorded high‐oxygen‐demand performance of mako sharks suggests it may be particularly vulnerable to habitat loss due to climate‐driven ocean deoxygenation.
... When compared with dead-reckoned tracks, linear movement models have shown significant mean position errors, large underestimations of total distances travelled by animals and inaccurate foraging area estimates [15,22,24]. Dead-reckoning has since been used to describe the movement of a range of terrestrial and marine species [25][26][27][28]. ...
Background
For diving, marine predators, accelerometer and magnetometer data provides critical information on sub-surface foraging behaviours that cannot be identified from location or time-depth data. By measuring head movement and body orientation, accelerometers and magnetometers can help identify broad shifts in foraging movements, fine-scale habitat use and energy expenditure of terrestrial and marine species. Here, we use accelerometer and magnetometer data from tagged Australian sea lions and provide a new method to identify key benthic foraging areas. As Australian sea lions are listed as endangered by the IUCN and Australian legislation, identifying key areas for the species is vital to support targeted management of populations.
Methods
Firstly, tri-axial magnetometer and accelerometer data from adult female Australian sea lions is used in conjunction with GPS and dive data to dead-reckon their three-dimensional foraging paths. We then isolate all benthic phases from their foraging trips and calculate a range of dive metrics to characterise their bottom usage. Finally, k-means cluster analysis is used to identify core benthic areas utilised by sea lions. Backwards stepwise regressions are then iteratively performed to identify the most parsimonious model for describing bottom usage and its included predictor variables.
Results
Our results show distinct spatial partitioning in benthic habitat-use by Australian sea lions. This method has also identified individual differences in benthic habitat-use. Here, the application of high-resolution magnetometer/accelerometer data has helped reveal the tortuous foraging movements Australian sea lions use to exploit key benthic marine habitats and features.
Conclusions
This study has illustrated how magnetometer and accelerometer data can provide a fine-scale description of the underwater movement of diving species, beyond GPS and depth data alone, For endangered species like Australian sea lions, management of populations must be spatially targeted. Here, this method demonstrates a fine-scale analysis of benthic habitat-use which can help identify key areas for both marine and terrestrial species. Future integration of this method with concurrent habitat and prey data would further augment its power as a tool for understanding the foraging behaviours of species.
... High-resolution acceleration biologging can fill the knowledge gap of how top pelagic predators may exploit vertical fronts because it allows for the examination of animal behaviours not under direct observation (Watanabe & Takahashi, 2013;Wilson et al., 2008;Yoda et al., 1999). By incorporating additional sensors such as triaxial magnetometers and gyroscopes, the animal's heading and turning can be directly quantified (Andrzejaczek et al., 2019;Williams, Holton, et al., 2017). Finally, by combining these animal movement sensors with abiotic variables such as depth, temperature and in situ oxygen concentration (Coffey & Holland, 2015), a more complete picture of animal movements and search behaviour in relation to vertical fronts can be attained. ...
Pelagic predators must contend with low prey densities that are irregularly distributed and dynamic in space and time. Based on satellite imagery and telemetry data, many pelagic predators will concentrate horizontal movements on ephemeral surface fronts—gradients between water masses—because of enhanced local productivity and increased forage fish densities.
Vertical fronts (e.g. thermoclines, oxyclines) can be spatially and temporally persistent, and aggregate lower trophic level and diel vertically migrating organisms due to sharp changes in temperature, water density or available oxygen. Thus, vertical fronts represent a stable and potentially energy rich habitat feature for diving pelagic predators but remain little explored in their capacity to enhance foraging opportunities.
Here, we use a novel suite of high‐resolution biologging data, including in situ derived oxygen saturation and video, to document how two top predators in the pelagic ecosystem exploit the vertical fronts created by the oxygen minimum zone of the eastern tropical Pacific.
Prey search behaviour was dependent on dive shape, and significantly increased near the thermocline and hypoxic boundary for blue marlin Makaira nigricans and sailfish Istiophorus platypterus, respectively. Further, we identify a behaviour not yet reported for pelagic predators, whereby the predator repeatedly dives below the thermocline and hypoxic boundary (and by extension, below the prey). We hypothesize this behaviour is used to ambush prey concentrated at the boundaries from below.
We describe how habitat fronts created by low oxygen environments can influence pelagic ecosystems, which will become increasingly important to understand in the context of global change and expanding oxygen minimum zones. We anticipate that our findings are shared among many pelagic predators where strong vertical fronts occur, and additional high‐resolution tagging is warranted to confirm this.
... Shark tagging and movement studies are numerous in the published literature (Hussey et al. 2015). However, the use of new technologies (heavier, potentially less hydrodynamic multi-sensor tags; Andrzejaczek et al. 2019) or new attachment methods (e.g., clamps; Chapple et al. 2015) warrants more observations on the fate of such tags and geolocators after long periods. Little is known about how the constant forward motion of some shark species might alter potential attachments on the fin, and the highly migratory behavior of some shark species that are the focus of tracking studies makes it challenging to document how different tags and geolocators behave on the fins after long time periods. ...
Objective:
Sharks face a high risk of injuries throughout all life stages and are therefore expected to show a good wound closure capacity.
Methods:
Here, the wound closure of one major injury and one minor injury to the first dorsal fins of two free-ranging, mature female Great Hammerheads Sphyrna mokarran is described macroscopically.
Result:
The sharks showed complete wound closure of single, clean-cut lacerations measuring 24.2 and 11.6 cm in length after an estimated 323 and 138 days. These estimates were based on the observed closure rate and visual confirmation of a complete wound closure upon multiple resightings of the same individuals. Additionally, the posterior lateral displacement of fin-mounted geolocators within the fin and outside of the fin without causing external damage was documented in three additional Great Hammerheads.
Conclusion:
These observations supplement findings about wound closure capabilities in elasmobranchs. The documented geolocator displacement furthers the discussion about the safe use of these geolocators to track shark movements but also has implications for future tagging studies.
... Pressure sensor data (Depth) and a maximum depth value of each hour of data (Depth_Max) were used to determine the depth use of sharks in different areas and times using the mask analysis in Ethographer. Vertical velocity (VV) was calculated using a 10-s running mean on depth use data and calculating the difference of successive periods using a 1-s interval (Andrzejaczek et al., 2018;Andrzejaczek, Gleiss, Lear, et al., 2019). These values were then converted to an absolute scale (VV_abs). ...
... Estimated pathways can be validated and adjusted using pitch, roll, and first location of SPOT transmissions post-release, yet may be subjected to significant error from environmental conditions (such as currents). As a result of these errors, dead reckoned paths are not a true representation of where movements took place but accurately predict the shape and angles of movement in three dimensions (Andrzejaczek, Gleiss, Lear, et al., 2019). Three separate time frames were selected, 1, 5, and 20 min, to account for finer (indicative of interactions with prey or habitat features, i.e., Jewell et al., 2019) and larger scale (indicative of residency periods or area-restricted search, i.e., Towner et al., 2016) changes in heading. ...
... At night, movements of sharks tagged at the Farallon Islands were away from the island group toward deeper waters, and at Año Nuevo they were away from the island rookery along the continental shelf. During the day, sharks were, in general, more active, engaged in more vertical movement, and swam in more tortuous paths (Figure 4), all of which have been linked to foraging behavior in other species of sharks where increased searching/encounter behavior is suggested by this type of locomotion (Andrzejaczek, Gleiss, Lear, et al., 2019;Gleiss et al., 2013;Lear et al., 2021). However, there were areas where crepuscular periods had similar patterns in locomotion, with sharks at the Farallon Islands and Aptos more active and tortuous at dawn and dusk, respectively. ...
An animal’s movement is influenced by a plethora of internal and external factors, leading to individual- and habitat-specific movement characteristics. This plasticity is thought to allow individuals to exploit diverse environments efficiently. We tested if the movement characteristics of white sharks Carcharodon carcharias differ across ontogeny and among habitats along the coast of Central California. In doing so, we elucidate how changes in internal state (physiological changes coinciding with body size) and external environments (differing seascapes and/or diel phases) shape the movement of this globally distributed predator. White sharks, from small juveniles to large adults, were equipped with motion-sensitive biologging tags at four contrasting seascapes: two islands, a headland, and an inshore cove. From multi-sensor biologging data, 20 metrics characterising movement were derived and subjected to multivariate analyses. Movement characteristics were most different across seascapes, followed by ontogeny and diel phase. Juvenile sharks, that were only encountered at the cove, displayed the most distinct movement characteristics. Sharks at this seascape remained close to the shore and were comparatively less active than sub-adult and adult sharks tagged elsewhere. Distinct night-time movements and dive patterns were recorded from sharks at an island seascape but not from those at the headland or inshore cove. The availability of prey and access to deeper water are likely drivers, with greater numbers of Northern elephant seals Mirounga angustirostris at the island seascapes and harbour seals Phoca vitulina at the headland seascape, while the offshore island group is also closer to the continental shelf edge. Juvenile sharks at the inshore cove are piscivorous and their habitat was not adjacent to pinniped haul out areas nor deeper water. This study demonstrates plasticity in the movements of a top predator, that adapts its routine to suit the habitat it forages within.
... Nevertheless, this knowledge is still limited due to the many obstacles involved in studying large, highly mobile animals in the wild. Due to recent advances in multi-sensor biologging technologies (accelerometers, magnetometers, gyroscopes, speed sensors, etc.), we can now start to comprehend fundamental aspects of animal behaviour through quantitative measurements of their body kinematics [6,[8][9][10]. Recent multi-sensor biologging studies, on endothermic and ectothermic sharks, have shown that sharks' swimming patterns are probably connected to behaviours that minimize energy expenditure while maximizing foraging opportunities [7,10,11]. ...
... Our mako sharks' diving patterns were consistent with this assumption, with most dives selected to identify optimum swimming strategies supporting an 'intentional' diving strategy, probably associated with prey-searching behaviour [28]. Burst swimming events, which possibly represent predation attempts or successes [8,9], were identified for sharks #01 and #02 almost exclusively during the daytime, when the sharks were yo-yo swimming within a wider portion of the water column, suggesting that this strategy may maximize prey encounter rates. Although most of the observed speed bursts were directed downwards, a sudden steep high-speed upward-directed movement (3.62 m s −1 ) was recorded for shark #01. ...
As regional endotherms, lamnid sharks can sustain high cruising speeds and perform frequent speed bursts. However, since endothermy comes with high energetic costs, lamnids may adopt different swimming strategies to manage their energy budget. Understanding such strategies is essential to provide behavioural and physiological context to their broader movement ecology. The endangered shortfin mako (Isurus oxyrinchus) possibly has the highest energy requirements among lamnids, but our understanding of its swimming behaviour is still limited. We equipped three shortfin mako sharks with high-resolution multi-sensor tags to measure their swimming kinematics in the wild. While swimming horizontally, individuals favoured tail-beat frequencies around 0.6 Hz at speeds comparable to those of ectothermic sharks (ca 0.5 m s⁻¹). All individuals displayed yo-yo-like diving patterns where, for a given tail-beat frequency, speeds were higher during descents, as expected for a negatively buoyant fish. Contrary to what was expected, gliding was almost absent (less than 1.31%). Speed bursts reaching up to 3.6 m s⁻¹ were observed during the day but ceased shortly after dusk, implying a diel change in swimming behaviour. As large-scale research efforts are hindered by this species' increasing rarity, opportunistic high-resolution datasets, like the present, are fundamental to improve our understanding of shortfin mako's behaviour and ecology.
