ORCID Profile
0000-0002-9960-2858
Current Organisation
Murdoch University
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Publisher: The Company of Biologists
Date: 04-2021
DOI: 10.1242/JEB.233544
Abstract: Dynamic body acceleration (DBA), measured through animal-attached tags, has emerged as a powerful method for estimating field metabolic rates of free-ranging in iduals. Following respirometry to calibrate oxygen consumption rate (ṀO2) with DBA under controlled conditions, predictive models can be applied to DBA data collected from free-ranging in iduals. However, laboratory calibrations are generally performed on a relatively narrow size range of animals, which may introduce biases if predictive models are applied to differently sized in iduals in the field. Here, we tested the mass dependence of the ṀO2–DBA relationship to develop an experimental framework for the estimation of field metabolic rates when organisms differ in size. We performed respirometry experiments with in iduals spanning one order of magnitude in body mass (1.74–17.15 kg) and used a two-stage modelling process to assess the intraspecific scale dependence of the ṀO2–DBA relationship and incorporate such dependencies into the coefficients of ṀO2 predictive models. The final predictive model showed scale dependence the slope of the ṀO2–DBA relationship was strongly allometric (M1.55), whereas the intercept term scaled closer to isometry (M1.08). Using bootstrapping and simulations, we evaluated the performance of this coefficient-corrected model against commonly used methods of accounting for mass effects on the ṀO2–DBA relationship and found the lowest error and bias in the coefficient-corrected approach. The strong scale dependence of the ṀO2–DBA relationship indicates that caution must be exercised when models developed using one size class are applied to in iduals of different sizes.
Publisher: Canadian Science Publishing
Date: 08-2015
Abstract: Quantifying fine-scale locomotor behaviours associated with different activities is challenging for free-swimming fish. Biologging and biotelemetry tools can help address this problem. An open channel flume was used to generate volitional swimming speed (U s ) estimates of cultured lake sturgeon (Acipenser fulvescens Rafinesque, 1817) and these were paired with simultaneously recorded accelerometer-derived metrics of activity obtained from three types of data-storage tags. This study examined whether a predictive relationship could be established between four different activity metrics (tail-beat frequency (TBF), tail-beat acceleration litude (TBAA), overall dynamic body acceleration (ODBA), and vectorial dynamic body acceleration (VeDBA)) and the swimming speed of A. fulvescens. Volitional U s of sturgeon ranged from 0.48 to 2.70 m·s −1 (0.51–3.18 body lengths (BL)·s −1 ). Swimming speed increased linearly with all accelerometer-derived metrics, and when all tag types were combined, U s increased 0.46 BL·s −1 for every 1 Hz increase in TBF, and 0.94, 0.61, and 0.94 BL·s −1 for every 1g increase in TBAA, ODBA, and VeDBA, respectively. Predictive relationships varied among tag types and tag-specific parameter estimates of U s are presented for all metrics. This use of acceleration data-storage tags demonstrated their applicability for the field quantification of sturgeon swimming speed.
Publisher: Springer Science and Business Media LLC
Date: 19-06-2021
DOI: 10.1007/S00227-021-03916-W
Abstract: Underwater visual surveys represent an essential component of coastal marine research and play a crucial role in supporting the management of marine systems. However, logistical and financial considerations can limit the availability of survey data in some systems. While biologging camera tag devices are being attached to an increasing ersity of marine animals to collect behavioral information about the focal species, the ancillary imagery collected can also be used in analytical techniques developed for er-based surveys. We illustrate this approach by extracting ancillary data from shark-borne camera tag deployments focused on the behavior of a White shark ( Carcharodon carcharias) off Gansbaai, South Africa, and a Grey Reef shark ( Carcharhinus amblyrhynchos) within the Chagos Archipelago. Within the giant kelp forest environment of Gansbaai we could determine the spatial density of kelp thali and underlying substrate composition. Within the coral reef environment, the animal-borne video allowed us to determine the approximate percent and type of benthic cover, as well as growth form and genus of corals down to the upper mesophotic zone. We also enumerated fish species-level abundance over reef flat and wall environments. We used established e-survey methods to analyze video data and found the results to be broadly comparable in the two systems studied. Our work illustrates the broad applicability of ancillary animal-borne video data, which is analogous in type and quality to er-based video data, for analysis in established marine community survey frameworks. As camera tags and associated biologging technologies continue to develop and are adapted to new environments, utilising these data could have wide-ranging applications and could maximise the overall cost–benefit ratio within biologging deployments.
Publisher: Inter-Research Science Center
Date: 05-09-2017
DOI: 10.3354/ESR00837
Publisher: Inter-Research Science Center
Date: 23-12-2008
DOI: 10.3354/AB00104
Publisher: Wiley
Date: 28-01-2016
Publisher: The Royal Society
Date: 08-2022
DOI: 10.1098/RSOS.211860
Abstract: Diving behaviour of ‘surfacers' such as sea snakes, cetaceans and turtles is complex and multi-dimensional, thus may be better captured by multi-sensor biologging data. However, analysing these large multi-faceted datasets remains challenging, though a high priority. We used high-resolution multi-sensor biologging data to provide the first detailed description of the environmental influences on flatback turtle ( Natator depressus ) ing behaviour, during its foraging life-history stage. We developed an analytical method to investigate seasonal, diel and tidal effects on ing behaviour for 24 adult flatback turtles tagged with biologgers. We extracted 16 e variables associated with three-dimensional and kinematic characteristics for 4128 es. K -means and hierarchical cluster analyses failed to identify distinct e types. Instead, principal component analysis objectively condensed the e variables, removing collinearity and highlighting the main features of ing behaviour. Generalized additive mixed models of the main principal components identified significant seasonal, diel and tidal effects on flatback turtle ing behaviour. Flatback turtles altered their ing behaviour in response to extreme tidal and water temperature ranges, displaying thermoregulation and predator avoidance strategies while likely optimizing foraging in this challenging environment. This study demonstrates an alternative statistical technique for objectively interpreting ing behaviour from multivariate collinear data derived from biologgers.
Publisher: Springer Science and Business Media LLC
Date: 23-08-2019
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.CUB.2014.11.050
Abstract: Cross-flows (winds or currents) affect animal movements [1-3]. Animals can temporarily be carried off course or permanently carried away from their preferred habitat by drift depending on their own traveling speed in relation to that of the flow [1]. Animals able to only weakly fly or swim will be the most impacted (e.g., [4]). To circumvent this problem, animals must be able to detect the effects of flow on their movements and respond to it [1, 2]. Here, we show that a weakly swimming organism, the jellyfish Rhizostoma octopus, can orientate its movements with respect to currents and that this behavior is key to the maintenance of blooms and essential to reduce the probability of stranding. We combined in situ observations with first-time deployment of accelerometers on free-ranging jellyfish and simulated the behavior observed in wild jellyfish within a high-resolution hydrodynamic model. Our results show that jellyfish can actively swim countercurrent in response to current drift, leading to significant life-history benefits, i.e., increased chance of survival and facilitated bloom formation. Current-oriented swimming may be achieved by jellyfish either directly detecting current shear across their body surface [5] or indirectly assessing drift direction using other cues (e.g., magnetic, infrasound). Our coupled behavioral-hydrodynamic model provides new evidence that current-oriented swimming contributes to jellyfish being able to form aggregations of hundreds to millions of in iduals for up to several months, which may have substantial ecosystem and socioeconomic consequences [6, 7]. It also contributes to improve predictions of jellyfish blooms' magnitude and movements in coastal waters.
Publisher: The Royal Society
Date: 13-07-2011
Abstract: Over-fishing may lead to a decrease in fish abundance and a proliferation of jellyfish. Active movements and prey search might be thought to provide a competitive advantage for fish, but here we use data-loggers to show that the frequently occurring coastal jellyfish ( Rhizostoma octopus ) does not simply passively drift to encounter prey. Jellyfish (327 days of data from 25 jellyfish with depth collected every 1 min) showed very dynamic vertical movements, with their integrated vertical movement averaging 619.2 m d −1 , more than 60 times the water depth where they were tagged. The majority of movement patterns were best approximated by exponential models describing normal random walks. However, jellyfish also showed switching behaviour from exponential patterns to patterns best fitted by a truncated Lévy distribution with exponents (mean μ = 1.96, range 1.2–2.9) close to the theoretical optimum for searching for sparse prey ( μ opt ≈ 2.0). Complex movements in these ‘simple’ animals may help jellyfish to compete effectively with fish for plankton prey, which may enhance their ability to increase in dominance in perturbed ocean systems.
Publisher: Wiley
Date: 18-04-2021
DOI: 10.1002/AQC.3578
Abstract: Sawfishes (Family: Pristidae) are one of the most imperilled fish families worldwide. There is an increasingly urgent need to better understand the biology, ecology, and population status of the five sawfish species to develop more effective conservation measures. The dwarf sawfish, Pristis clavata , is one of the least researched members of the pristids, with literature limited to analysing disparate datasets or collations of rare encounters in northern Australia. This study examined the spatial ecology of dwarf sawfish using targeted surveys and acoustic telemetry to determine its habitat use in a macrotidal estuary in northern Australia. Seventeen dwarf sawfish were tagged with acoustic transmitters and monitored in the Fitzroy River estuary and adjacent King Sound (Kimberley, Western Australia) between August 2015 and November 2017. Dwarf sawfish observed within the Fitzroy River estuary and King Sound were juveniles, ranging between 740 and 2,540 mm in total length. Catch per unit effort of dwarf sawfish in the late dry season was relatively high in the estuary, with the catch rate in 2015 being one of the highest reported for any sawfish species. Acoustic detections revealed a distinct seasonal pattern in the use of different parts of the estuary and King Sound, which was found to be driven by salinity. Dwarf sawfish predominately occupied a single large pool near the terminus of the tidal limit in the late dry season (August–November), before transitioning to regions in closer proximity to the river mouth or in King Sound in the wet and early dry seasons (December–July). Given the high abundance and residency of dwarf sawfish in the Fitzroy River estuary, this area is an important nursery for the species during the late dry season and should be formally recognized as a habitat protection area for the species.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Oxford University Press (OUP)
Date: 29-11-2017
Publisher: Springer Science and Business Media LLC
Date: 26-07-2016
DOI: 10.1038/NCOMMS12289
Abstract: Animals exhibit various physiological and behavioural strategies for minimizing travel costs. Fins of aquatic animals play key roles in efficient travel and, for sharks, the functions of dorsal and pectoral fins are considered well ided: the former assists propulsion and generates lateral hydrodynamic forces during turns and the latter generates vertical forces that offset sharks’ negative buoyancy. Here we show that great hammerhead sharks drastically reconfigure the function of these structures, using an exaggerated dorsal fin to generate lift by swimming rolled on their side. Tagged wild sharks spend up to 90% of time swimming at roll angles between 50° and 75°, and hydrodynamic modelling shows that doing so reduces drag—and in turn, the cost of transport—by around 10% compared with traditional upright swimming. Employment of such a strongly selected feature for such a unique purpose raises interesting questions about evolutionary pathways to hydrodynamic adaptations, and our perception of form and function.
Publisher: Elsevier BV
Date: 08-2023
Publisher: Springer Science and Business Media LLC
Date: 02-11-2015
Publisher: Wiley
Date: 24-11-2011
Publisher: Elsevier BV
Date: 04-2016
Publisher: Wiley
Date: 14-05-2023
Abstract: The value of assisted colonisation as a response to climate change can only be realised if focal species are well suited to their new habitats. For ectotherms, new habitats must offer microclimates that promote crucial behaviours such as thermoregulation and foraging. The Western sw turtle Pseudemydura umbrina , a Critically Endangered species from south‐western Australia, serves as a global case‐study of assisted colonisation in action. Initial trials where juvenile P. umbrina were released into wetter and cooler climates found that in iduals spent considerable time at body temperatures that apparently limited their growth. Using high‐resolution biologging data (temperature and depth), here we tested if turtle activity is thermally constrained in cooler latitudes by releasing 48 juveniles into seasonal sw s at three sites. One site was core natural habitat, and the other sites were wetlands 380 km apart that offered either warmer or cooler microclimates. Generalised additive mixed models were used to evaluate behaviours and time spent at optimal temperatures for approximately 1 month following release, and growth rates were measured and analysed after release until the end of the hydroperiod 4–5 months later. We found that turtles released into the most poleward (southern) wetland spent significantly less time active and basking and grew significantly less compared to turtles released further north. When analysed together, behavioural and growth datasets showed that activity was positively correlated with growth rates. We conclude that poor growth of turtles in the southern wetland was likely a result of lower body temperatures, stemming from a reduced ability to thermoregulate in water. Consequently, for assisted colonisation of juvenile P. umbrina to be successful, recipient wetlands must offer aquatic microclimates that are sufficiently warm to promote foraging activity that leads to growth, and ultimately to maturation. Read the free Plain Language Summary for this article on the Journal blog.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Wiley
Date: 12-02-2021
DOI: 10.1002/ECY.3251
Publisher: Elsevier BV
Date: 04-2010
Publisher: The Company of Biologists
Date: 15-08-2016
DOI: 10.1242/JEB.140087
Abstract: Fish migrations through riverine systems can be energetically demanding, and the presence of fishways to facilitate upstream passage can add an additional energetic cost that may directly affect fitness. Successful fishway passage is a function of the ability of fish to select appropriate paths and swimming strategies that do not exceed their swimming capacity. Triaxial accelerometers were used to estimate the energetic expenditure of adult lake sturgeon (Acipenser fulvescens) swimming through a vertical slot fishway, to determine whether in idual behaviour or path selection, resulting in differences in cumulative energy use, explain fishway passage success. Most in iduals attempted to pass the fishway (n=30/44 68%), although successful passage only occurred for a subset of those attempting (n=7/30 23%). High-speed swimming was rarely observed during upstream passage through fishway basins, and was of short duration. Two turning basins delayed passage, subsequently resulting in a higher energetic cost. The rate at which energy was expended did not differ among successful and unsuccessful in iduals, although successful sturgeon exhibited higher costs of transport (42.75 versus 25.85 J kg−1 m−1). Energy expenditure metrics were not predictive of successful fishway passage, leading us to conclude that other endogenous or exogenous factors influence passage success. In a practical application of field measurements of energy expenditure, we demonstrate that fishway passage through a structure designed to facilitate migration does result in an energetic loss for lake sturgeon (3249–16,331 J kg−1), equivalent to in iduals travelling 5.8–28.2 km in a lentic system.
Publisher: University of Chicago Press
Date: 05-2020
DOI: 10.1086/708247
Publisher: Springer Science and Business Media LLC
Date: 08-03-2018
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.CBPA.2016.01.005
Abstract: Specific dynamic action (SDA), the increase in metabolic expenditure associated with consumption of a meal, represents a substantial portion of fish energy budgets and is highly influenced by ambient temperature. The effect of temperature on SDA has not been studied in yellowfin tuna (Thunnus albacares, Bonnaterre 1788), an active pelagic predator that occupies temperate and subtropical waters. The energetic cost and duration of SDA were calculated by comparing routine and post-prandial oxygen consumption rates. Mean routine metabolic rates in yellowfin tuna increased with temperature, from 136 mg O2 kg(-1)h(-1) at 20 °C to 211 mg O2 kg(-1)h at 24 °C. The mean duration of SDA decreased from 40.2h at 20 °C to 33.1h at 24 °C, while mean SDA coefficient, the percentage of energy in a meal that is consumed during digestion, increased from 5.9% at 20 °C to 12.7% at 24 °C. Digestion in yellowfin tuna is faster at a higher temperature but requires additional oxidative energy. Enhanced characterization of the role of temperature in SDA of yellowfin tuna deepens our understanding of tuna physiology and can help improve management of aquaculture and fisheries.
Publisher: Wiley
Date: 04-2021
Abstract: Bio‐logging data obtained by tagging animals are key to addressing global conservation challenges. However, the many thousands of existing bio‐logging datasets are not easily discoverable, universally comparable, nor readily accessible through existing repositories and across platforms, slowing down ecological research and effective management. A set of universal standards is needed to ensure discoverability, interoperability and effective translation of bio‐logging data into research and management recommendations. We propose a standardisation framework adhering to existing data principles (FAIR: Findable, Accessible, Interoperable and Reusable and TRUST: Transparency, Responsibility, User focus, Sustainability and Technology) and involving the use of simple templates to create a data flow from manufacturers and researchers to compliant repositories, where automated procedures should be in place to prepare data availability into four standardised levels: (a) decoded raw data, (b) curated data, (c) interpolated data and (d) gridded data. Our framework allows for integration of simple tabular arrays (e.g. csv files) and creation of sharable and interoperable network Common Data Form (netCDF) files containing all the needed information for accuracy‐of‐use, rightful attribution (ensuring data providers keep ownership through the entire process) and data preservation security. We show the standardisation benefits for all stakeholders involved, and illustrate the application of our framework by focusing on marine animals and by providing ex les of the workflow across all data levels, including filled templates and code to process data between levels, as well as templates to prepare netCDF files ready for sharing. Adoption of our framework will facilitate collection of Essential Ocean Variables (EOVs) in support of the Global Ocean Observing System (GOOS) and inter‐governmental assessments (e.g. the World Ocean Assessment), and will provide a starting point for broader efforts to establish interoperable bio‐logging data formats across all fields in animal ecology.
Publisher: Wiley
Date: 02-2017
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CBPA.2019.01.025
Abstract: Bluefin tunas are highly specialized fish with unique hydrodynamic designs and physiological traits. In this study, we present results in a captive population that demonstrate strong effects of ambient temperature on the tail beat frequency and swimming speed of a pelagic fish in both pre- and post-prandial states. We measured the responses of a ram ventilator, the Pacific bluefin tuna (Thunnus orientalis), after digestion of a meal to explore the impacts of the metabolic costs of digestion on behavior and respiration. A combination of respirometry, physiological biologging of visceral temperatures, and activity monitoring with accelerometry were used to explore the metabolic costs of digestion and the impacts on ventilation and swimming speed. Experiments were conducted at temperatures that are within the metabolic optimum for Pacific bluefin tuna (17 °C), and at a second temperature corresponding to the upper distributional limit of the species in the California Current (24 °C). Warmer temperatures resulted in higher tail-beat frequency and greater elevation of body temperature in pre-prandial Pacific bluefin tuna. Specific dynamic action (SDA) events resulted in a significant postprandial increase in tail-beat frequency of ~0.2 Hz, compared to pre-prandial levels of 1.5 Hz (17 °C) and 1.75 Hz (24 °C), possibly resulting from ventilatory requirements. Data of fish exercised in a swim-tunnel respirometer suggest that the observed increase in tail-beat frequency comprise 5.5 and 6.8% of the oxygen demand during peak SDA at 24 °C and 17 °C respectively. The facultative increase in swimming speed might increase oxygen uptake at the gills to meet the increasing demand by visceral organs involved in the digestive process, potentially decreasing the available energy of each meal for other metabolic processes, such as growth, maturation, and reproduction. We hypothesize that these post-prandial behaviors allow tuna to evacuate their guts more quickly, ultimately permitting fish to feed more frequently when prey is available.
Publisher: The Royal Society
Date: 05-2019
DOI: 10.1098/RSOS.190203
Abstract: Tunas possess a range of physiological and mechanical adaptations geared towards high-performance swimming that are of considerable interest to physiologists, ecologists and engineers. Advances in biologging have provided significant improvements in understanding tuna migrations and vertical movement patterns, yet our understanding of the locomotion and swimming mechanics of these fish under natural conditions is limited. We equipped Atlantic bluefin tuna ( Thunnus thynnus ) with motion-sensitive tags and video cameras to quantify the gaits and kinematics used by wild fish. Our data reveal significant variety in the locomotory kinematics of Atlantic bluefin tuna, ranging from continuous locomotion to two types of intermittent locomotion. The tuna sustained swimming speeds in excess of 1.5 m s −1 (0.6 body lengths s −1 ), while beating their tail at a frequency of approximately 1 Hz. While ing, some descents were entirely composed of passive glides, with slower descent rates featuring more gliding, while ascents were primarily composed of active swimming. The observed swimming behaviour of Atlantic bluefin tuna is consistent with theoretical models predicting such intermittent locomotion to result in mechanical and physiological advantages. Our results confirm that Atlantic bluefin tuna possess behavioural specializations to increase their locomotory performance, which together with their unique physiology improve their capacity to use pelagic and mesopelagic habitats.
Publisher: NMFS Publications Office
Date: 17-12-2019
DOI: 10.7755/FB.117.4.7
Publisher: The Company of Biologists
Date: 2014
DOI: 10.1242/JEB.080697
Abstract: A spring emergence of avian haemosporidian infections is nearly universal among temperate zone birds and is often described as a cost of reproductive effort. We take advantage of the opportunistic (i.e., aseasonal) breeding schedule of the red crossbill (Loxia curvirostra) to determine the relative contributions of season vs. host physiology to the timing and intensity of Haemoproteus infections in the temperate zone. Despite breeding activity in both the winter and summer, Haemoproteus infections were highly seasonal- occurring largely from May through September- and measures of host physiology (i.e., reproductive condition and stress parameters) did not explain parasite prevalence. However, within the spring-summer peak, infection intensity (i.e., parasite density) was positively correlated with plasma levels of testosterone and free corticosterone and negatively correlated with corticosterone binding globulin capacity. These data are discussed in terms of the behavioral ecology of host and vector, and suggest that both seasonal increases in vector activity and relapse of latent (i.e., dormant) infections contribute to the spring emergence in birds. Relapse of latent infections does not appear to be induced by reproductive activity or increased allostatic (i.e., energy) load, but rather by a season-specific change in host or parasite physiology (e.g., melatonin or endogenous rhythms).
Publisher: The Company of Biologists
Date: 04-2015
DOI: 10.1242/JEB.114868
Abstract: Major transitions between marine and freshwater habitats are relatively infrequent, primarily as a result of major physiological and ecological challenges. Few species of cartilaginous fish have evolved to occupy freshwater habitats. Current thought suggests that the metabolic physiology of sharks has remained a barrier to the ersification of this taxon in freshwater ecosystems. Here, we demonstrate that the physical properties of water provide an additional constraint for this species-rich group to occupy freshwater systems. Using hydromechanical modeling, we show that occurrence in fresh water results in a two- to three-fold increase in negative buoyancy for sharks and rays. This carries the energetic cost of lift production and results in increased buoyancy-dependent mechanical power requirements for swimming and increased optimal swim speeds. The primary source of buoyancy, the lipid-rich liver, offers only limited compensation for increased negative buoyancy as a result of decreasing water density maintaining the same submerged weight would involve increasing the liver volume by very large amounts: 3- to 4-fold in scenarios where liver density is also reduced to currently observed minimal levels and 8-fold without any changes in liver density. The first data on body density from two species of elasmobranch occurring in freshwater (the bull shark Carcharhinus leucas, Müller and Henle 1839, and the largetooth sawfish Pristis pristis, Linnaeus 1758) support this hypothesis, showing similar liver sizes as marine forms but lower liver densities, but the greatest negative buoyancies of any elasmobranch studied to date. Our data suggest that the mechanical challenges associated with buoyancy control may have h ered the invasion of freshwater habitats in elasmobranchs, highlighting an additional key factor that may govern the predisposition of marine organisms to successfully establish in freshwater habitats.
Publisher: Oxford University Press (OUP)
Date: 03-2017
DOI: 10.1093/ICB/ICX002
Publisher: Springer Science and Business Media LLC
Date: 12-09-2023
Publisher: Wiley
Date: 2011
Publisher: Springer Science and Business Media LLC
Date: 2021
Publisher: The Royal Society
Date: 08-11-2017
Abstract: Buoyancy control is a fundamental aspect of aquatic life that has major implications for locomotor performance and ecological niche. Unlike terrestrial animals, the densities of aquatic animals are similar to the supporting fluid, thus even small changes in body density may have profound effects on locomotion. Here, we analysed the body composition (lipid versus lean tissue) of 32 shark species to study the evolution of buoyancy. Our comparative phylogenetic analyses indicate that although lean tissue displays minor positive allometry, liver volume exhibits pronounced positive allometry, suggesting that larger sharks evolved bulkier body compositions by adding lipid tissue to lean tissue rather than substituting lean for lipid tissue, particularly in the liver. We revealed a continuum of buoyancy control strategies that ranged from more buoyant sharks with larger livers in deeper ecosystems to relatively denser sharks with small livers in epipelagic habitats. Across this eco-morphological spectrum, our hydrodynamic modelling suggests that neutral buoyancy yields lower drag and more efficient steady swimming, whereas negative buoyancy may be more efficient during accelerated movements. The evolution of buoyancy control in sharks suggests that ecological and physiological factors mediate the selective pressures acting on these traits along two major gradients, body size and habitat depth.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/MF18182
Abstract: Measuring the metabolic rate of animals is an essential part of understanding their ecology, behaviour and life history. Respirometry is the standard method of measuring metabolism in fish, but different respirometry methods and systems can result in disparate measurements of metabolic rate, a factor often difficult to quantify. Here we directly compare the results of two of the most common respirometry systems used in elasmobranch studies, a Steffensen-style flume respirometer and an annular static respirometer. Respirometry trials with juvenile lemon sharks Negaprion brevirostris were run in both systems under the same environmental conditions and using the same in iduals. Relationships between metabolic rate, swimming speed, overall dynamic body acceleration (ODBA) and tail beat frequency (TBF) were compared between the two systems. The static respirometer elicited higher TBF and ODBA for a given swimming speed compared with the flume respirometer, although it produced relationships between kinematic parameters that were more similar to those observed in free-swimming animals. Metabolic rates and swimming speeds were higher for the flume respirometer. Therefore, although flume respirometers are necessary for many types of controlled laboratory studies, static respirometers may elicit lower stress and produce results that are more applicable to fish in wild systems.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Springer Science and Business Media LLC
Date: 06-2015
Publisher: Elsevier BV
Date: 09-2022
Publisher: Springer Science and Business Media LLC
Date: 19-11-2019
DOI: 10.1038/S41598-019-53511-9
Abstract: The freshwater sawfish ( Pristis pristis ) was recently listed as the most Evolutionarily Distinct and Globally Endangered (EDGE) animal. The Fitzroy River in the remote Kimberley region of north-western Australia represents a significant stronghold for the species, which uses the freshwater reaches of the river as a nursery. There is also mounting pressure to develop the water resources of the region for agriculture that may substantially affect life history dynamics of sawfish in this system. However, the relationship between hydrology and population dynamics of freshwater sawfish was unknown. We used standardized catch data collected over 17 years to determine how wet season volume influences recruitment of freshwater sawfish into their riverine nursery. Negligible recruitment occurred in years with few days of high flood levels (above 98 th percentile of cease-to-flow stage height), and relatively high recruitment occurred in years with 14 or more days of high flood levels. This relationship is indicative of a distinct boom-or-bust cycle, whereby freshwater sawfish rely almost entirely on the few years with large wet season floods, and the brief periods of highest water levels within these years, to replenish juvenile populations in the Fitzroy River nursery. This has direct implications for sustainable water resource management for the Fitzroy River basin in order to preserve one of the last known intact nursery habitats for this globally threatened species.
Publisher: CRC Press
Date: 09-04-2012
DOI: 10.1201/B11867-17
Publisher: Springer Science and Business Media LLC
Date: 20-05-2020
Publisher: Public Library of Science (PLoS)
Date: 17-02-2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-05-2023
Abstract: Hammerhead sharks hold their breath when ing to regulate body temperature
Publisher: Wiley
Date: 29-06-2023
Abstract: Conservation of threatened species and anthropogenic threat mitigation commonly rely on spatially managed areas selected according to habitat preference. Since the impact of threats can be behaviour‐specific, such information could be incorporated into spatial management to improve conservation outcomes. However, collecting spatially explicit behavioural data is challenging. Using multi‐sensor biologging tags containing high‐resolution movement sensors (e.g. accelerometer, magnetometer, GPS) and animal‐borne video cameras, combined with supervised machine learning, we developed a method to automatically detect and geolocate typically ambiguous behaviours for the poorly understood flatback turtle Natator depressus . Subsequently, we evaluated behaviour‐specific spatiotemporal patterns of habitat use. Boosted regression trees successfully identified the presence of foraging and resting in 7074 es (AUC 0.9), using e features representing characteristics of locomotory activity, body posture, and three‐dimensional e paths validated by ancillary video data. Foraging was characterised by es with longer duration, variable depth, tortuous bottom phases resting was characterised by es with decreased locomotory activity and longer duration bottom phases. Foraging and resting showed minimal spatial segregation based on 50% and 95% utilisation distributions. Expected diel patterns of behaviour‐specific habitat use were superseded by the extreme tides at the near‐shore study site. Turtles rested in areas close to the subtidal and intertidal boundary within larger overlapping foraging areas, allowing efficient access to intertidal food resources upon inundation at high tides when foraging was ~25% more likely. Synthesis and applications . Using supervised machine learning and biologging tools, we show the potential for dynamic spatial management of flatback turtles to mitigate behaviour‐specific threats by prioritising protection of important locations at pertinent times. Although results are a species‐specific response to a super‐tidal environment, our approach can be generalised to a broad range of taxa and study systems, facilitating a conceptual advance in spatial management.
Publisher: The Company of Biologists
Date: 2016
DOI: 10.1242/JEB.146993
Abstract: The ability to produce estimates of the metabolic rate of free-ranging animals is fundamental to the study of their ecology. However, measuring the energy expenditure of animals in the field has proven difficult, especially for aquatic taxa. Accelerometry presents a means of translating metabolic rates measured in the laboratory to in iduals studied in the field, pending appropriate laboratory calibrations. Such calibrations have only been performed on a few fish species to date, and only one where the effects of temperature were accounted for. Here we present calibrations between activity, measured as overall dynamic body acceleration (ODBA), and metabolic rate, measured through respirometry, for nurse sharks (Ginglymostoma cirratum), lemon sharks (Negaprion brevirostris), and blacktip sharks (Carcharhinus limbatus). Calibrations were made at a range of volitional swimming speeds and experimental temperatures. Linear mixed models were used to determine a predictive equation for metabolic rate based on measured ODBA values, with the optimal model using ODBA in combination with activity state and temperature to predict metabolic rate in lemon and nurse sharks, and ODBA and temperature to predict metabolic rate in blacktip sharks. This study lays the groundwork for calculating the metabolic rate of these species in the wild using acceleration data.
Publisher: Elsevier BV
Date: 2021
Publisher: The Royal Society
Date: 04-2019
Abstract: Traditional forms of marine wildlife research are often restricted to coarse telemetry or surface-based observations, limiting information on fine-scale behaviours such as predator–prey events and interactions with habitat features. We use contemporary animal-attached cameras with motion sensing dataloggers, to reveal novel behaviours by white sharks, Carcharodon carcharias , within areas of kelp forest in South Africa. All white sharks tagged in this study spent time adjacent to kelp forests, with several moving throughout densely kelp-covered areas, navigating through channels and pushing directly through stipes and fronds. We found that activity and turning rates significantly increased within kelp forest. Over 28 h of video data revealed that white shark encounters with Cape fur seals, Arctocephalus pusillus pusillus , occurred exclusively within kelp forests, with seals displaying predator evasion behaviour during those encounters. Uniquely, we reveal the use of kelp forest habitat by white sharks, previously assumed inaccessible to these large predators.
Publisher: Elsevier BV
Date: 04-2009
Publisher: Elsevier BV
Date: 08-2022
Publisher: Wiley
Date: 26-01-2012
Publisher: Springer Science and Business Media LLC
Date: 29-05-2018
DOI: 10.1038/S41598-018-26485-3
Abstract: Large-bodied pelagic ectotherms such as sharks need to maintain internal temperatures within a favourable range in order to maximise performance and be cost-efficient foragers. This implies that behavioural thermoregulation should be a key feature of the movements of these animals, although field evidence is limited. We used depth and temperature archives from pop-up satellite tags to investigate the role of temperature in driving vertical movements of 16 oceanic whitetip sharks, Carcharhinus longimanus , (OWTs). Spectral analysis, linear mixed modelling, segmented regression and multivariate techniques were used to examine the effect of mean sea surface temperature (SST) and mixed layer depth on vertical movements. OWTs continually oscillated throughout the upper 200 m of the water column. In summer when the water column was stratified with high SSTs, oscillations increased in litude and cycle length and sharks reduced the time spent in the upper 50 m. In winter when the water column was cooler and well-mixed, oscillations decreased in litude and cycle length and sharks frequently occupied the upper 50 m. SSTs of 28 o C marked a distinct change in vertical movements and the onset of thermoregulation strategies. Our results have implications for the ecology of these animals in a warming ocean.
Publisher: Springer Science and Business Media LLC
Date: 24-08-2017
Publisher: Springer Science and Business Media LLC
Date: 08-11-2019
DOI: 10.1007/S00442-019-04547-1
Abstract: Temperature is one of the most influential drivers of physiological performance and behaviour in ectotherms, determining how these animals relate to their ecosystems and their ability to succeed in particular habitats. Here, we analysed the largest set of acceleration data compiled to date for elasmobranchs to examine the relationship between volitional activity and temperature in 252 in iduals from 8 species. We calculated activation energies for the thermal performance response in each species and estimated optimum temperatures using an Arrhenius breakpoint analysis, subsequently fitting thermal performance curves to the activity data. Juveniles living in confined nursery habitats not only spent substantially more time above their optimum temperature and at the upper limits of their performance breadths compared to larger, less site-restricted animals, but also showed lower activation energies and broader performance curves. Species or life stages occupying confined habitats featured more generalist behavioural responses to temperature change, whereas wider ranging elasmobranchs were characterised by more specialist behavioural responses. The relationships between the estimated performance regimes and environmental temperature limits suggest that animals in confined habitats, including many juvenile elasmobranchs within nursery habitats, are likely to experience a reduction of performance under a warming climate, although their flatter thermal response will likely d en this impact. The effect of warming on less site-restricted species is difficult to forecast since three of four species studied here did not reach their optimum temperature in the wild, although their specialist performance characteristics may indicate a more rapid decline should optimum temperatures be exceeded.
Publisher: Wiley
Date: 08-2018
DOI: 10.1111/JFB.13663
Abstract: This study reports on the metabolic rate of the blacktip shark Carcharhinus limbatus and the energetic costs of external tag attachment. Metabolic rates, swimming speed and tail-beat (B
Publisher: Cold Spring Harbor Laboratory
Date: 27-07-2020
DOI: 10.1101/2020.07.24.219204
Abstract: Life history, reproduction, and survival are fundamentally linked to energy expenditure and acquisition. Dynamic Body Acceleration (DBA), measured through animal-attached data-loggers or transmitters, has emerged as a powerful method for estimating field metabolic rates of free-ranging in iduals. After using respirometry to calibrate oxygen consumption rate with DBA in captive settings, predictive models can be applied to DBA data collected from free-ranging in iduals. However, laboratory calibrations are generally performed on a narrow size range of animals, which may introduce biases when predictive models are applied to differently sized in iduals in the field. Here, we tested the influence of scale effects on the ability of a single predictive model to predict over a range of body sizes. We performed respirometry experiments with in iduals spanning one order of magnitude in body mass (1.74–17.15 kg) and used a two-step modelling process to assess the intra-specific scale dependence of the -DBA relationship and incorporate such dependencies into the covariates of predictive models. The final predictive model showed scale dependence the slope of the -DBA relationship was strongly allometric (M 1.55 ), whereas the intercept term scaled closer to isometry (M 1.08 ). Using bootstrapping and simulations, we tested the performance of this covariate-corrected model against commonly used methods of accounting for mass effects on the -DBA relationship and found lowest error and bias in the covariate-corrected approach. The strong scale dependence of the -DBA relationship indicates that caution must be exercised when models developed using one size class are applied to in iduals of different sizes. The relationship between oxygen consumption rate and dynamic body acceleration is allometrically dependent, and models incorporate different slope and intercept scaling rates estimate metabolic rates more accurately than mass-specific approaches.
Publisher: The Royal Society
Date: 08-2020
DOI: 10.1098/RSOS.200789
Abstract: Tiger sharks, Galeocerdo cuvier , are a keystone, top-order predator that are assumed to engage in cost-efficient movement and foraging patterns. To investigate the extent to which oscillatory ing by tiger sharks conform to these patterns, we used a biologging approach to model their cost of transport. High-resolution biologging tags with tri-axial sensors were deployed on 21 tiger sharks at Ningaloo Reef for durations of 5–48 h. Using overall dynamic body acceleration as a proxy for energy expenditure, we modelled the cost of transport of oscillatory movements of varying geometries in both horizontal and vertical planes for tiger sharks. The cost of horizontal transport was minimized by descending at the smallest possible angle and ascending at an angle of 5–14°, meaning that vertical oscillations conserved energy compared to swimming at a level depth. The reduction of vertical travel costs occurred at steeper angles. The absolute e angles of tiger sharks increased between inshore and offshore zones, presumably to reduce the cost of transport while continuously hunting for prey in both benthic and surface habitats. Oscillatory movements of tiger sharks conform to strategies of cost-efficient foraging, and shallow inshore habitats appear to be an important habitat for both hunting prey and conserving energy while travelling.
Publisher: The Company of Biologists
Date: 12-2010
DOI: 10.1242/JEB.048207
Abstract: In the face of the physical and physiological challenges of performing breath-hold deep es, marine vertebrates have evolved different strategies. Although behavioural strategies in marine mammals and seabirds have been investigated in detail, little is known about the deepest- ing reptile – the leatherback turtle (Dermochelys coriacea). Here, we deployed tri-axial accelerometers on female leatherbacks nesting on St Croix, US Virgin Islands, to explore their ing strategy. Our results show a consistent behavioural pattern within es among in iduals, with an initial period of active swimming at relatively steep descent angles (∼–40 deg), with a stroke frequency of 0.32 Hz, followed by a gliding phase. The depth at which the gliding phase began increased with the maximum depth of the es. In addition, descent body angles and vertical velocities were higher during deeper es. Leatherbacks might thus regulate their inspired air-volume according to the intended e depth, similar to hard-shelled turtles and penguins. During the ascent, turtles actively swam with a stroke frequency of 0.30 Hz but with a low vertical velocity (∼0.40 ms–1) and a low pitch angle (∼+26 deg). Turtles might avoid succumbing to decompression sickness (‘the bends’) by ascending slowly to the surface. In addition, we suggest that the low body temperature of this marine ectotherm compared with that of endotherms might help reduce the risk of bubble formation by increasing the solubility of nitrogen in the blood. This physiological advantage, coupled with several behavioural and physical adaptations, might explain the particular ecological niche the leatherback turtle occupies among marine reptiles.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-08-2022
Abstract: Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Springer Science and Business Media LLC
Date: 08-04-2019
Publisher: Wiley
Date: 28-09-2020
DOI: 10.1002/ECO.2253
Publisher: Inter-Research Science Center
Date: 26-09-2017
DOI: 10.3354/ESR00847
Publisher: Frontiers Media SA
Date: 14-05-2019
Publisher: Cold Spring Harbor Laboratory
Date: 11-06-2023
DOI: 10.1101/2023.06.08.544203
Abstract: Home range size and metabolic rate of animals are expected to scale with body mass at similar rates with home ranges expanding to meet increased metabolic requirements. This expectation has widely been tested using lab-derived estimates of basal metabolic rate as proxies for field energy requirements, however, it is unclear if existing theory aligns with patterns of home range scaling observed in the field. Here, we conduct the first direct field test of the relationship between home range and metabolic rate allometry. Using acoustic telemetry, we simultaneously measured the in idual home range size and field metabolic rate of lemon sharks (Negaprion brevirostris) spanning one order of magnitude in body mass. Although scaling rates of field metabolic rate were consistent with standard metabolic rate, home range size scaled at shallower rates than metabolic rates. This is evidence for strong top-down controls on home range scaling rates, likely a result of predation pressure placing constraints on home range expansions. Consequently, direct resource competition can lead to decreased home range scaling rates. We highlight inconsistencies with theory on the effects of population density and competition on home range scaling and propose that the influence of erse types of competition should be examined.
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.TREE.2016.02.015
Abstract: It is a golden age for animal movement studies and so an opportune time to assess priorities for future work. We assembled 40 experts to identify key questions in this field, focussing on marine megafauna, which include a broad range of birds, mammals, reptiles, and fish. Research on these taxa has both underpinned many of the recent technical developments and led to fundamental discoveries in the field. We show that the questions have broad applicability to other taxa, including terrestrial animals, flying insects, and swimming invertebrates, and, as such, this exercise provides a useful roadmap for targeted deployments and data syntheses that should advance the field of movement ecology.
Publisher: Wiley
Date: 05-03-2020
DOI: 10.1111/JFB.14287
Publisher: Inter-Research Science Center
Date: 31-03-2008
DOI: 10.3354/ESR00084
Publisher: Springer Science and Business Media LLC
Date: 24-05-2021
DOI: 10.1186/S40462-021-00248-8
Abstract: Tri-axial accelerometers have been used to remotely describe and identify in situ behaviours of a range of animals without requiring direct observations. Datasets collected from these accelerometers (i.e. acceleration, body position) are often large, requiring development of semi-automated analyses to classify behaviours. Marine fishes exhibit many “burst” behaviours with high litude accelerations that are difficult to interpret and differentiate. This has constrained the development of accurate automated techniques to identify different “burst” behaviours occurring naturally, where direct observations are not possible. We trained a random forest machine learning algorithm based on 624 h of accelerometer data from six captive yellowtail kingfish during spawning periods. We identified five distinct behaviours (swim, feed, chafe, escape, and courtship), which were used to train the model based on 58 predictive variables. Overall accuracy of the model was 94%. Classification of each behavioural class was variable F 1 scores ranged from 0.48 (chafe) – 0.99 (swim). The model was subsequently applied to accelerometer data from eight free-ranging kingfish, and all behaviour classes described from captive fish were predicted by the model to occur, including 19 events of courtship behaviours ranging from 3 s to 108 min in duration. Our findings provide a novel approach of applying a supervised machine learning model on free-ranging animals, which has previously been predominantly constrained to direct observations of behaviours and not predicted from an unseen dataset. Additionally, our findings identify typically ambiguous spawning and courtship behaviours of a large pelagic fish as they naturally occur.
Publisher: The Royal Society
Date: 07-07-2021
Abstract: Niche partitioning of time, space or resources is considered the key to allowing the coexistence of competitor species, and particularly guilds of predators. However, the extent to which these processes occur in marine systems is poorly understood due to the difficulty in studying fine-scale movements and activity patterns in mobile underwater species. Here, we used acceleration data-loggers to investigate temporal partitioning in a guild of marine predators. Six species of co-occurring large coastal sharks demonstrated distinct diel patterns of activity, providing evidence of strong temporal partitioning of foraging times. This is the first instance of diel temporal niche partitioning described in a marine predator guild, and is probably driven by a combination of physiological constraints in diel timing of activity (e.g. sensory adaptations) and interference competition (hierarchical predation within the guild), which may force less dominant predators to suboptimal foraging times to avoid agonistic interactions. Temporal partitioning is often thought to be rare compared to other partitioning mechanisms, but the occurrence of temporal partitioning here and similar characteristics in many other marine ecosystems (multiple predators simultaneously present in the same space with dietary overlap) introduces the question of whether this is a common mechanism of resource ision in marine systems.
Publisher: Wiley
Date: 10-04-2017
DOI: 10.1002/ECY.1737
Publisher: Elsevier BV
Date: 04-2011
Publisher: Oxford University Press (OUP)
Date: 15-10-2016
Publisher: Elsevier BV
Date: 2024
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Adrian Gleiss.