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Sutton GJ, Angel LP, Speakman JR, Arnould JPY. Determining energy expenditure in a large seabird using accelerometry. J Exp Biol 2023; 226:jeb246922. [PMID: 37947172 PMCID: PMC10714144 DOI: 10.1242/jeb.246922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
The trade off between energy gained and expended is the foundation of understanding how, why and when animals perform any activity. Based on the concept that animal movements have an energetic cost, accelerometry is increasingly being used to estimate energy expenditure. However, validation of accelerometry as an accurate proxy for field metabolic rate in free-ranging species is limited. In the present study, Australasian gannets (Morus serrator) from the Pope's Eye colony (38°16'42″S 144°41'48″E), south-eastern Australia, were equipped with GPS and tri-axial accelerometers and dosed with doubly labelled water (DLW) to measure energy expenditure during normal behaviour for 3-5 days. The correlation between daily energy expenditure from the DLW and vectorial dynamic body acceleration (VeDBA) was high for both a simple correlation and activity-specific approaches (R2=0.75 and 0.80, respectively). Varying degrees of success were observed for estimating at-sea metabolic rate from accelerometry when removing time on land using published energy expenditure constants (R2=0.02) or activity-specific approaches (R2=0.42). The predictive capacity of energy expenditure models for total and at-sea periods was improved by the addition of total distance travelled and proportion of the sampling period spent at sea during the night, respectively (R2=0.61-0.82). These results indicate that accelerometry can be used to estimate daily energy expenditure in free-ranging gannets and its accuracy may depend on the inclusion of movement parameters not detected by accelerometry.
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Affiliation(s)
- Grace J. Sutton
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
- Department of Environment & Genetics, and Research Centre for Future Landscapes, La Trobe University, Bundoora, VIC 3086, Australia
| | - Lauren P. Angel
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
| | - John R. Speakman
- Institute of Environmental and Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advance Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
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2
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Noren SR, Rosen DAS. What are the Metabolic Rates of Marine Mammals and What Factors Impact this Value: A review. CONSERVATION PHYSIOLOGY 2023; 11:coad077. [PMID: 37790839 PMCID: PMC10545007 DOI: 10.1093/conphys/coad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 08/22/2023] [Accepted: 09/14/2023] [Indexed: 10/05/2023]
Abstract
Over the past several decades, scientists have constructed bioenergetic models for marine mammals to assess potential population-level consequences following exposure to a disturbance, stressor, or environmental change, such as under the Population Consequences of Disturbance (pCOD) framework. The animal's metabolic rate (rate of energy expenditure) is a cornerstone for these models, yet the cryptic lifestyles of marine mammals, particularly cetaceans, have limited our ability to quantify basal (BMR) and field (FMR) metabolic rates using accepted 'gold standard' approaches (indirect calorimeter via oxygen consumption and doubly labeled water, respectively). Thus, alternate methods have been used to quantify marine mammal metabolic rates, such as extrapolating from known allometric relationships (e.g. Kleiber's mouse to elephant curve) and developing predictive relationships between energy expenditure and physiological or behavioral variables. To understand our current knowledge of marine mammal metabolic rates, we conducted a literature review (1900-2023) to quantify the magnitude and variation of metabolic rates across marine mammal groups. A compilation of data from studies using 'gold standard' methods revealed that BMR and FMR of different marine mammal species ranges from 0.2 to 3.6 and 1.1 to 6.1 x Kleiber, respectively. Mean BMR and FMR varied across taxa; for both measures odontocete levels were intermediate to higher values for otariids and lower values of phocids. Moreover, multiple intrinsic (e.g. age, sex, reproduction, molt, individual) and extrinsic (e.g. food availability, water temperature, season) factors, as well as individual behaviors (e.g. animal at water's surface or submerged, activity level, dive effort and at-sea behaviors) impact the magnitude of these rates. This review provides scientists and managers with a range of reliable metabolic rates for several marine mammal groups as well as an understanding of the factors that influence metabolism to improve the discernment for inputs into future bioenergetic models.
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Affiliation(s)
- S R Noren
- Institute of Marine Science, University of California Santa Cruz, Center for Ocean Health, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4
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3
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Christensen C, Bracken AM, O'Riain MJ, Fehlmann G, Holton M, Hopkins P, King AJ, Fürtbauer I. Quantifying allo-grooming in wild chacma baboons ( Papio ursinus) using tri-axial acceleration data and machine learning. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221103. [PMID: 37063984 PMCID: PMC10090879 DOI: 10.1098/rsos.221103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 03/15/2023] [Indexed: 06/19/2023]
Abstract
Quantification of activity budgets is pivotal for understanding how animals respond to changes in their environment. Social grooming is a key activity that underpins various social processes with consequences for health and fitness. Traditional methods use direct (focal) observations to calculate grooming rates, providing systematic but sparse data. Accelerometers, in contrast, can quantify activity budgets continuously but have not been used to quantify social grooming. We test whether grooming can be accurately identified using machine learning (random forest model) trained on labelled acceleration data from wild chacma baboons (Papio ursinus). We successfully identified giving and receiving grooming with high precision (81% and 91%) and recall (87% and 79%). Giving grooming was associated with a distinct rhythmical signal along the surge axis. Receiving grooming had similar acceleration signals to resting, and thus was more difficult to assign. We applied our machine learning model to n = 680 collar data days from n = 12 baboons and found that grooming rates obtained from accelerometers were significantly and positively correlated with direct observation rates for giving but not receiving grooming. The ability to collect continuous grooming data in wild populations will allow researchers to re-examine and expand upon long-standing questions regarding the formation and function of grooming bonds.
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Affiliation(s)
- Charlotte Christensen
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
- Department of Evolutionary Biology and Environmental Science, University of Zurich, Zurich 8057, Switzerland
| | - Anna M. Bracken
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - M. Justin O'Riain
- Institute for Communities and Wildlife in Africa, Department of Biological Science, University of Cape Town, Rondebosch, 7701, South Africa
| | - Gaëlle Fehlmann
- Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany
| | - Mark Holton
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
| | - Phillip Hopkins
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
| | - Andrew J. King
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
| | - Ines Fürtbauer
- Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
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4
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Allegue H, Réale D, Picard B, Guinet C. Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator. MOVEMENT ECOLOGY 2023; 11:3. [PMID: 36681811 PMCID: PMC9862577 DOI: 10.1186/s40462-022-00361-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 12/17/2022] [Indexed: 06/08/2023]
Abstract
BACKGROUND Studying animal movement in the context of the optimal foraging theory has led to the development of simple movement metrics for inferring feeding activity. Yet, the predictive capacity of these metrics in natural environments has been given little attention, raising serious questions of the validity of these metrics. The aim of this study is to test whether simple continuous movement metrics predict feeding intensity in a marine predator, the southern elephant seal (SES; Mirounga leonine), and investigate potential factors influencing the predictive capacity of these metrics. METHODS We equipped 21 female SES from the Kerguelen Archipelago with loggers and recorded their movements during post-breeding foraging trips at sea. From accelerometry, we estimated the number of prey encounter events (nPEE) and used it as a reference for feeding intensity. We also extracted several track- and dive-based movement metrics and evaluated how well they explain and predict the variance in nPEE. We conducted our analysis at two temporal scales (dive and day), with two dive profile resolutions (high at 1 Hz and low with five dive segments), and two types of models (linear models and regression trees). RESULTS We found that none of the movement metrics predict nPEE with satisfactory power. The vertical transit rates (primarily the ascent rate) during dives had the best predictive performance among all metrics. Dive metrics performed better than track metrics and all metrics performed on average better at the scale of days than the scale of dives. However, the performance of the models at the scale of days showed higher variability among individuals suggesting distinct foraging tactics. Dive-based metrics performed better when computed from high-resolution dive profiles than low-resolution dive profiles. Finally, regression trees produced more accurate predictions than linear models. CONCLUSIONS Our study reveals that simple movement metrics do not predict feeding activity in free-ranging marine predators. This could emerge from differences between individuals, temporal scales, and the data resolution used, among many other factors. We conclude that these simple metrics should be avoided or carefully tested a priori with the studied species and the ecological context to account for significant influencing factors.
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Affiliation(s)
- Hassen Allegue
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada.
| | - Denis Réale
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Baptiste Picard
- Centre d'Etudes Biologiques de Chizé, UMR7372 CNRS-La Rochelle Université, Villiers en Bois, France
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé, UMR7372 CNRS-La Rochelle Université, Villiers en Bois, France
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5
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The role of individual variability on the predictive performance of machine learning applied to large bio-logging datasets. Sci Rep 2022; 12:19737. [PMID: 36396680 PMCID: PMC9672113 DOI: 10.1038/s41598-022-22258-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/12/2022] [Indexed: 11/18/2022] Open
Abstract
Animal-borne tagging (bio-logging) generates large and complex datasets. In particular, accelerometer tags, which provide information on behaviour and energy expenditure of wild animals, produce high-resolution multi-dimensional data, and can be challenging to analyse. We tested the performance of commonly used artificial intelligence tools on datasets of increasing volume and dimensionality. By collecting bio-logging data across several sampling seasons, datasets are inherently characterized by inter-individual variability. Such information should be considered when predicting behaviour. We integrated both unsupervised and supervised machine learning approaches to predict behaviours in two penguin species. The classified behaviours obtained from the unsupervised approach Expectation Maximisation were used to train the supervised approach Random Forest. We assessed agreement between the approaches, the performance of Random Forest on unknown data and the implications for the calculation of energy expenditure. Consideration of behavioural variability resulted in high agreement (> 80%) in behavioural classifications and minimal differences in energy expenditure estimates. However, some outliers with < 70% of agreement, highlighted how behaviours characterized by signal similarity are confused. We advise the broad bio-logging community, approaching these large datasets, to be cautious when upscaling predictions, as this might lead to less accurate estimates of behaviour and energy expenditure.
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Rautiainen H, Alam M, Blackwell PG, Skarin A. Identification of reindeer fine-scale foraging behaviour using tri-axial accelerometer data. MOVEMENT ECOLOGY 2022; 10:40. [PMID: 36127747 PMCID: PMC9490970 DOI: 10.1186/s40462-022-00339-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/10/2022] [Indexed: 06/15/2023]
Abstract
Animal behavioural responses to the environment ultimately affect their survival. Monitoring animal fine-scale behaviour may improve understanding of animal functional response to the environment and provide an important indicator of the welfare of both wild and domesticated species. In this study, we illustrate the application of collar-attached acceleration sensors for investigating reindeer fine-scale behaviour. Using data from 19 reindeer, we tested the supervised machine learning algorithms Random forests, Support vector machines, and hidden Markov models to classify reindeer behaviour into seven classes: grazing, browsing low from shrubs or browsing high from trees, inactivity, walking, trotting, and other behaviours. We implemented leave-one-subject-out cross-validation to assess generalizable results on new individuals. Our main results illustrated that hidden Markov models were able to classify collar-attached accelerometer data into all our pre-defined behaviours of reindeer with reasonable accuracy while Random forests and Support vector machines were biased towards dominant classes. Random forests using 5-s windows had the highest overall accuracy (85%), while hidden Markov models were able to best predict individual behaviours and handle rare behaviours such as trotting and browsing high. We conclude that hidden Markov models provide a useful tool to remotely monitor reindeer and potentially other large herbivore species behaviour. These methods will allow us to quantify fine-scale behavioural processes in relation to environmental events.
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Affiliation(s)
- Heidi Rautiainen
- Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden.
| | - Moudud Alam
- School of Information and Engineering, Dalarna University, Falun, Sweden
| | - Paul G Blackwell
- School of Mathematics & Statistics, University of Sheffield, Sheffield, UK
| | - Anna Skarin
- Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden
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7
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Kinoshita C, Saito A, Sakamoto KQ, Yasuaki N, Sato K. Heart rate as a proxy for estimating oxygen consumption rates in loggerhead turtles (Caretta caretta). Biol Open 2022; 11:274558. [PMID: 35225332 PMCID: PMC8988048 DOI: 10.1242/bio.058952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 02/21/2022] [Indexed: 11/20/2022] Open
Abstract
Heart rates of air-breathing diving animals can change on a short time scale due to the diving response during submergence. Heart rate is used frequently as a proxy for indirectly estimating metabolic rates on a fine time scale. However, most studies to date have been conducted on endothermic diving animals, and the relationships between metabolic rates and heart rates in ectothermic diving animals have not been well studied. Sea turtles are unique model organisms of diving ectotherms because they spend most of their life in the ocean and perform deep and/or long dives. In this study, we examined the relationship between heart rates and metabolic rates in captive loggerhead turtles, Caretta caretta, to estimate oxygen consumption rates during each dive based on heart rates. The oxygen consumption rates (V̇O2: mlO2 min−1 kg−1) and average heart rates (fH: beats min−1) were measured simultaneously in indoor tanks at water temperatures of 15–25°C. Our results showed that oxygen consumption rate was affected by heart rate and water temperature in loggerhead turtles. Based on the collected data, we formulated the model equation as V̇O2=0.0124fH+0.0047Tw - 0.0791. The equation can be used for estimating fine-scaled field metabolic rates in free-ranging loggerhead turtles. The results of this study will contribute to future comparative studies of the physiological states of ectothermic diving animals. Summary: The relationship between oxygen consumption rate and heart rate in the loggerhead turtle.
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Affiliation(s)
- Chihiro Kinoshita
- International Coastal Research Center, The Atmosphere and Ocean Research Institute, The University of Tokyo, 1-19-8 Akahama, Otsuch, Iwate 028-1102, Japan
| | - Ayaka Saito
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Kentaro Q Sakamoto
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Niizuma Yasuaki
- Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi 468-8502, Japan
| | - Katsufumi Sato
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
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8
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Allen AS, Read AJ, Shorter KA, Gabaldon J, Blawas AM, Rocho-Levine J, Fahlman A. Dynamic body acceleration as a proxy to predict the cost of locomotion in bottlenose dolphins. J Exp Biol 2022; 225:274390. [PMID: 35014667 DOI: 10.1242/jeb.243121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/05/2022] [Indexed: 11/20/2022]
Abstract
Estimates of the energetic costs of locomotion (COL) at different activity levels are necessary to answer fundamental eco-physiological questions and to understand the impacts of anthropogenic disturbance to marine mammals. We combined estimates of energetic costs derived from breath-by-breath respirometry with measurements of overall dynamic body acceleration (ODBA) from biologging tags to validate ODBA as a proxy for COL in trained common bottlenose dolphins (Tursiops truncatus). We measured resting metabolic rate (RMR); mean individual RMR was 0.71-1.42 times that of a similarly sized terrestrial mammal and agreed with past measurements which used breath-by-breath and flow-through respirometry. We also measured energy expenditure during submerged swim trials, at primarily moderate exercise levels. We subtracted RMR to obtain COL, and normalized COL by body size to incorporate individual swimming efficiencies. We found both mass-specific energy expenditure and mass-specific COL were linearly related with ODBA. Measurements of activity level and cost of transport (the energy required to move a given distance) improve understanding of the costs of locomotion in marine mammals. The strength of the correlation between ODBA and COL varied among individuals, but the overall relationship can be used at a broad scale to estimate the energetic costs of disturbance, daily locomotion costs to build energy budgets, and investigate the costs of diving in free-ranging animals where bio-logging data are available. We propose that a similar approach could be applied to other cetacean species.
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Affiliation(s)
| | | | - K Alex Shorter
- Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | | | | | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, Research Department, Valencia, Spain.,Global Diving Research S.L., Valencia, Spain
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10
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Sidrow E, Heckman N, Fortune SME, Trites AW, Murphy I, Auger‐Méthé M. Modelling multi‐scale, state‐switching functional data with hidden Markov models. CAN J STAT 2021. [DOI: 10.1002/cjs.11673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Evan Sidrow
- Department of Statistics University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Nancy Heckman
- Department of Statistics University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Sarah M. E. Fortune
- Marine Mammal Research Unit University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Andrew W. Trites
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
- Institute for the Oceans and Fisheries University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Ian Murphy
- Department of Biostatistics University of Florida Gainesville 32611 FL U.S.A
| | - Marie Auger‐Méthé
- Department of Statistics University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
- Institute for the Oceans and Fisheries University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
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11
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Chimienti M, Beest FM, Beumer LT, Desforges J, Hansen LH, Stelvig M, Schmidt NM. Quantifying behavior and life‐history events of an Arctic ungulate from year‐long continuous accelerometer data. Ecosphere 2021. [DOI: 10.1002/ecs2.3565] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Marianna Chimienti
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
| | - Floris M. Beest
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
- Arctic Research Centre Aarhus University Ny Munkegade 116 Aarhus C8000Denmark
| | - Larissa T. Beumer
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
- Arctic Research Centre Aarhus University Ny Munkegade 116 Aarhus C8000Denmark
| | - Jean‐Pierre Desforges
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
- Arctic Research Centre Aarhus University Ny Munkegade 116 Aarhus C8000Denmark
- Natural Resource Sciences McGill University Ste Anne de Bellevue QuebecH9X 3V9Canada
| | - Lars H. Hansen
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
- Arctic Research Centre Aarhus University Ny Munkegade 116 Aarhus C8000Denmark
| | - Mikkel Stelvig
- Centre for Zoo and Wild Animal Health Copenhagen Zoo Frederiksberg2000Denmark
| | - Niels Martin Schmidt
- Department of Bioscience Aarhus University Frederiksborgvej 399 Roskilde4000Denmark
- Arctic Research Centre Aarhus University Ny Munkegade 116 Aarhus C8000Denmark
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12
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Blakeway JA, Arnould JPY, Hoskins AJ, Martin-Cabrera P, Sutton GJ, Huckstadt LA, Costa DP, Páez-Rosas D, Villegas-Amtmann S. Influence of hunting strategy on foraging efficiency in Galapagos sea lions. PeerJ 2021; 9:e11206. [PMID: 33954042 PMCID: PMC8051337 DOI: 10.7717/peerj.11206] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/12/2021] [Indexed: 11/20/2022] Open
Abstract
The endangered Galapagos sea lion (GSL, Zalophus wollebaeki) exhibits a range of foraging strategies utilising various dive types including benthic, epipelagic and mesopelagic dives. In the present study, potential prey captures (PPC), prey energy consumption and energy expenditure in lactating adult female GSLs (n = 9) were examined to determine their foraging efficiency relative to the foraging strategy used. Individuals displayed four dive types: (a) epipelagic (<100 m; EP); or (b) mesopelagic (>100 m; MP) with a characteristic V-shape or U-shape diving profile; and (c) shallow benthic (<100 m; SB) or (d) deep benthic (>100 m; DB) with square or flat-bottom dive profiles. These dive types varied in the number of PPC, assumed prey types, and the energy expended. Prey items and their energetic value were assumed from previous GSL diet studies in combination with common habitat and depth ranges of the prey. In comparison to pelagic dives occurring at similar depths, when diving benthically, GSLs had both higher prey energy consumption and foraging energy expenditure whereas PPC rate was lower. Foraging efficiency varied across dive types, with benthic dives being more profitable than pelagic dives. Three foraging trip strategies were identified and varied relative to prey energy consumed, energy expended, and dive behaviour. Foraging efficiency did not significantly vary among the foraging trip strategies suggesting that, while individuals may diverge into different foraging habitats, they are optimal within them. These findings indicate that these three strategies will have different sensitivities to habitat-specific fluctuations due to environmental change.
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Affiliation(s)
- Jessica-Anne Blakeway
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC, Australia
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC, Australia
| | | | | | - Grace J Sutton
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC, Australia
| | - Luis A Huckstadt
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
| | - Daniel P Costa
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, United States of America
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito and Galapagos Science Center, Islas Galápagos, Ecuador.,Dirección Parque Nacional Galápagos, Oficina Técnica Operativa San Cristóbal, Islas Galápagos, Ecuador
| | - Stella Villegas-Amtmann
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
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13
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Sutton GJ, Botha JA, Speakman JR, Arnould JPY. Validating accelerometry-derived proxies of energy expenditure using the doubly labelled water method in the smallest penguin species. Biol Open 2021; 10:bio.055475. [PMID: 33722801 PMCID: PMC8034874 DOI: 10.1242/bio.055475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Understanding energy use is central to understanding an animal's physiological and behavioural ecology. However, directly measuring energy expenditure in free-ranging animals is inherently difficult. The doubly labelled water (DLW) method is widely used to investigate energy expenditure in a range of taxa. Although reliable, DLW data collection and analysis is both financially costly and time consuming. Dynamic body acceleration (e.g. VeDBA) calculated from animal-borne accelerometers has been used to determine behavioural patterns, and is increasingly being used as a proxy for energy expenditure. Still its performance as a proxy for energy expenditure in free-ranging animals is not well established and requires validation against established methods. In the present study, the relationship between VeDBA and the at-sea metabolic rate calculated from DLW was investigated in little penguins (Eudyptula minor) using three approaches. Both in a simple correlation and activity-specific approaches were shown to be good predictors of at-sea metabolic rate. The third approach using activity-specific energy expenditure values obtained from literature did not accurately calculate the energy expended by individuals. However, all three approaches were significantly strengthened by the addition of mean horizontal travel speed. These results provide validation for the use of accelerometry as a proxy for energy expenditure and show how energy expenditure may be influenced by both individual behaviour and environmental conditions.
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Affiliation(s)
- G J Sutton
- School of Life and Environmental Sciences, Faculty of Science & Technology, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
| | - J A Botha
- Marine Apex Predator Research Unit (MAPRU), Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth 6031, South Africa
| | - J R Speakman
- Institute of Environmental and Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.,Center for Metabolism, Reproduction and Aging, Shenzhen Institutes of Advance Technology, Chinese Academy of Sciences, Shenzhen, China
| | - J P Y Arnould
- School of Life and Environmental Sciences, Faculty of Science & Technology, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
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14
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Ladds M, Rosen D, Gerlinsky C, Slip D, Harcourt R. Diving deep into trouble: the role of foraging strategy and morphology in adapting to a changing environment. CONSERVATION PHYSIOLOGY 2020; 8:coaa111. [PMID: 34168880 PMCID: PMC8218901 DOI: 10.1093/conphys/coaa111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/02/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Physiology places constraints on an animal's ability to forage and those unable to adapt to changing conditions may face increased challenges to reproduce and survive. As the global marine environment continues to change, small, air-breathing, endothermic marine predators such as otariids (fur seals and sea lions) and particularly females, who are constrained by central place foraging during breeding, may experience increased difficulties in successfully obtaining adequate food resources. We explored whether physiological limits of female otariids may be innately related to body morphology (fur seals vs sea lions) and/or dictate foraging strategies (epipelagic vs mesopelagic or benthic). We conducted a systematic review of the increased body of literature since the original reviews of Costa et al. (When does physiology limit the foraging behaviour of freely diving mammals? Int Congr Ser 2004;1275:359-366) and Arnould and Costa (Sea lions in drag, fur seals incognito: insights from the otariid deviants. In Sea Lions of the World Fairbanks. Alaska Sea Grant College Program, Alaska, USA, pp. 309-324, 2006) on behavioural (dive duration and depth) and physiological (total body oxygen stores and diving metabolic rates) parameters. We estimated calculated aerobic dive limit (cADL-estimated duration of aerobic dives) for species and used simulations to predict the proportion of dives that exceeded the cADL. We tested whether body morphology or foraging strategy was the primary predictor of these behavioural and physiological characteristics. We found that the foraging strategy compared to morphology was a better predictor of most parameters, including whether a species was more likely to exceed their cADL during a dive and the ratio of dive time to cADL. This suggests that benthic and mesopelagic divers are more likely to be foraging at their physiological capacity. For species operating near their physiological capacity (regularly exceeding their cADL), the ability to switch strategies is limited as the cost of foraging deeper and longer is disproportionally high, unless it is accompanied by physiological adaptations. It is proposed that some otariids may not have the ability to switch foraging strategies and so be unable adapt to a changing oceanic ecosystem.
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Affiliation(s)
- Monique Ladds
- Marine Ecosystems Team, Department of Conservation, Wellington 6011, New Zealand
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
| | - David Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries,
University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Carling Gerlinsky
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries,
University of British Columbia, Vancouver V6T 1Z4, Canada
| | - David Slip
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
- Taronga Conservation Society Australia, Mosman 2088, Australia
| | - Robert Harcourt
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
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15
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Kadar JP, Ladds MA, Day J, Lyall B, Brown C. Assessment of Machine Learning Models to Identify Port Jackson Shark Behaviours Using Tri-Axial Accelerometers. SENSORS 2020; 20:s20247096. [PMID: 33322308 PMCID: PMC7763149 DOI: 10.3390/s20247096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 01/08/2023]
Abstract
Movement ecology has traditionally focused on the movements of animals over large time scales, but, with advancements in sensor technology, the focus can become increasingly fine scale. Accelerometers are commonly applied to quantify animal behaviours and can elucidate fine-scale (<2 s) behaviours. Machine learning methods are commonly applied to animal accelerometry data; however, they require the trial of multiple methods to find an ideal solution. We used tri-axial accelerometers (10 Hz) to quantify four behaviours in Port Jackson sharks (Heterodontus portusjacksoni): two fine-scale behaviours (<2 s)-(1) vertical swimming and (2) chewing as proxy for foraging, and two broad-scale behaviours (>2 s-mins)-(3) resting and (4) swimming. We used validated data to calculate 66 summary statistics from tri-axial accelerometry and assessed the most important features that allowed for differentiation between the behaviours. One and two second epoch testing sets were created consisting of 10 and 20 samples from each behaviour event, respectively. We developed eight machine learning models to assess their overall accuracy and behaviour-specific accuracy (one classification tree, five ensemble learners and two neural networks). The support vector machine model classified the four behaviours better when using the longer 2 s time epoch (F-measure 89%; macro-averaged F-measure: 90%). Here, we show that this support vector machine (SVM) model can reliably classify both fine- and broad-scale behaviours in Port Jackson sharks.
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Affiliation(s)
- Julianna P. Kadar
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia;
- Correspondence:
| | - Monique A. Ladds
- Marine Ecosystems Team, Wellington University, Wellington 6012, New Zealand;
| | - Joanna Day
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Sydney, NSW 2088, Australia;
| | - Brianne Lyall
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre, Midlothian EH25 9RG, UK;
| | - Culum Brown
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia;
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16
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Hicks O, Kato A, Angelier F, Wisniewska DM, Hambly C, Speakman JR, Marciau C, Ropert-Coudert Y. Acceleration predicts energy expenditure in a fat, flightless, diving bird. Sci Rep 2020; 10:21493. [PMID: 33299039 PMCID: PMC7726140 DOI: 10.1038/s41598-020-78025-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
Energy drives behaviour and life history decisions, yet it can be hard to measure at fine scales in free-moving animals. Accelerometry has proven a powerful tool to estimate energy expenditure, but requires calibration in the wild. This can be difficult in some environments, or for particular behaviours, and validations have produced equivocal results in some species, particularly air-breathing divers. It is, therefore, important to calibrate accelerometry across different behaviours to understand the most parsimonious way to estimate energy expenditure in free-living conditions. Here, we combine data from miniaturised acceleration loggers on 58 free-living Adélie penguins with doubly labelled water (DLW) measurements of their energy expenditure over several days. Across different behaviours, both in water and on land, dynamic body acceleration was a good predictor of independently measured DLW-derived energy expenditure (R2 = 0.72). The most parsimonious model suggested different calibration coefficients are required to predict behaviours on land versus foraging behaviour in water (R2 = 0.75). Our results show that accelerometry can be used to reliably estimate energy expenditure in penguins, and we provide calibration equations for estimating metabolic rate across several behaviours in the wild.
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Affiliation(s)
- Olivia Hicks
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France.
| | - Akiko Kato
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Frederic Angelier
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Danuta M Wisniewska
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Coline Marciau
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Yan Ropert-Coudert
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
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17
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Williams TM, Peter‐Heide Jørgensen M, Pagano AM, Bryce CM. Hunters versus hunted: New perspectives on the energetic costs of survival at the top of the food chain. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13649] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Terrie M. Williams
- Department of Ecology and Evolutionary Biology Coastal Biology Building University of California Santa Cruz Santa Cruz CA USA
| | | | - Anthony M. Pagano
- Institute for Conservation Research San Diego Zoo Global San Diego CA USA
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18
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Energetics as common currency for integrating high resolution activity patterns into dynamic energy budget-individual based models. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109250] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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Tattersall GJ, Danner RM, Chaves JA, Levesque DL. Activity analysis of thermal imaging videos using a difference imaging approach. J Therm Biol 2020; 91:102611. [PMID: 32716861 DOI: 10.1016/j.jtherbio.2020.102611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/16/2020] [Accepted: 04/26/2020] [Indexed: 01/02/2023]
Abstract
Infrared thermal imaging is a passive imaging technique that captures the emitted radiation from an object to estimate surface temperature, often for inference of heat transfer. Infrared thermal imaging offers the potential to detect movement without the challenges of glare, shadows, or changes in lighting associated with visual digital imaging or active infrared imaging. In this paper, we employ a frame subtraction algorithm for extracting the pixel-by-pixel relative change in signal from a fixed focus video file, tailored for use with thermal imaging videos. By summing the absolute differences across an entire video, we are able to assign quantitative activity assessments to thermal imaging data for comparison with simultaneous recordings of metabolic rates. We tested the accuracy and limits of this approach by analyzing movement of a metronome and provide an example application of the approach to a study of Darwin's finches. In principle, this "Difference Imaging Thermography" (DIT) would allow for activity data to be standardized to energetic measurements and could be applied to any radiometric imaging system.
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Affiliation(s)
- Glenn J Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S3A1, Canada.
| | - Raymond M Danner
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Rd, Wilmington, NC, 28403, USA
| | - Jaime A Chaves
- Colegio de Ciencias Biológicas y Ambientales, Campus Cumbayá, Universidad San Francisco de Quito, Diego de Robles y Av. Interoceánica, Cumbayá, Quito, Ecuador; Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA, 94132, USA
| | - Danielle L Levesque
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia; School of Biology and Ecology, University of Maine, Orono, ME, USA
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20
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Gunner RM, Wilson RP, Holton MD, Scott R, Hopkins P, Duarte CM. A new direction for differentiating animal activity based on measuring angular velocity about the yaw axis. Ecol Evol 2020; 10:7872-7886. [PMID: 32760571 PMCID: PMC7391348 DOI: 10.1002/ece3.6515] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 12/11/2022] Open
Abstract
The use of animal-attached data loggers to quantify animal movement has increased in popularity and application in recent years. High-resolution tri-axial acceleration and magnetometry measurements have been fundamental in elucidating fine-scale animal movements, providing information on posture, traveling speed, energy expenditure, and associated behavioral patterns. Heading is a key variable obtained from the tandem use of magnetometers and accelerometers, although few field investigations have explored fine-scale changes in heading to elucidate differences in animal activity (beyond the notable exceptions of dead-reckoning).This paper provides an overview of the value and use of animal heading and a prime derivative, angular velocity about the yaw axis, as an important element for assessing activity extent with potential to allude to behaviors, using "free-ranging" Loggerhead turtles (Caretta caretta) as a model species.We also demonstrate the value of yaw rotation for assessing activity extent, which varies over the time scales considered and show that various scales of body rotation, particularly rate of change of yaw, can help resolve differences between fine-scale behavior-specific movements. For example, oscillating yaw movements about a central point of the body's arc implies bouts of foraging, while unusual circling behavior, indicative of conspecific interactions, could be identified from complete revolutions of the longitudinal axis.We believe this approach should help identification of behaviors and "space-state" approaches to enhance our interpretation of behavior-based movements, particularly in scenarios where acceleration metrics have limited value, such as for slow-moving animals.
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Affiliation(s)
- Richard M. Gunner
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Rory P. Wilson
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Mark D. Holton
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Rebecca Scott
- Future Ocean Cluster of ExcellenceGEOMAR Helmholtz Centre for Ocean ResearchKielGermany
- Natural Environmental Research Council, Polaris HouseSwindonUK
| | - Phil Hopkins
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Carlos M. Duarte
- Red Sea Research CentreKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
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21
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Sutton G, Pichegru L, Botha JA, Kouzani AZ, Adams S, Bost CA, Arnould JPY. Multi-predator assemblages, dive type, bathymetry and sex influence foraging success and efficiency in African penguins. PeerJ 2020; 8:e9380. [PMID: 32655991 PMCID: PMC7333648 DOI: 10.7717/peerj.9380] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/28/2020] [Indexed: 11/20/2022] Open
Abstract
Marine predators adapt their hunting techniques to locate and capture prey in response to their surrounding environment. However, little is known about how certain strategies influence foraging success and efficiency. Due to the miniaturisation of animal tracking technologies, a single individual can be equipped with multiple data loggers to obtain multi-scale tracking information. With the addition of animal-borne video data loggers, it is possible to provide context-specific information for movement data obtained over the video recording periods. Through a combination of video data loggers, accelerometers, GPS and depth recorders, this study investigated the influence of habitat, sex and the presence of other predators on the foraging success and efficiency of the endangered African penguin, Spheniscus demersus, from two colonies in Algoa Bay, South Africa. Due to limitations in the battery life of video data loggers, a machine learning model was developed to detect prey captures across full foraging trips. The model was validated using prey capture signals detected in concurrently recording accelerometers and animal-borne cameras and was then applied to detect prey captures throughout the full foraging trip of each individual. Using GPS and bathymetry information to inform the position of dives, individuals were observed to perform both pelagic and benthic diving behaviour. Females were generally more successful on pelagic dives than males, suggesting a trade-off between manoeuvrability and physiological diving capacity. By contrast, males were more successful in benthic dives, at least for Bird Island (BI) birds, possibly due to their larger size compared to females, allowing them to exploit habitat deeper and for longer durations. Both males at BI and both sexes at St Croix (SC) exhibited similar benthic success rates. This may be due to the comparatively shallower seafloor around SC, which could increase the likelihood of females capturing prey on benthic dives. Observation of camera data indicated individuals regularly foraged with a range of other predators including penguins and other seabirds, predatory fish (sharks and tuna) and whales. The presence of other seabirds increased individual foraging success, while predatory fish reduced it, indicating competitive exclusion by larger heterospecifics. This study highlights novel benthic foraging strategies in African penguins and suggests that individuals could buffer the effects of changes to prey availability in response to climate change. Furthermore, although group foraging was prevalent in the present study, its influence on foraging success depends largely on the type of heterospecifics present.
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Affiliation(s)
- Grace Sutton
- School of Life and Environmental Sciences, Faculty of Science & Technology, Deakin University, Burwood, Victoria, Australia.,Centre d'Études Biologiques de Chizé, UMR7372 CNRS/Univ La Rochelle, Villiers-en-Bois, France
| | - Lorien Pichegru
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Institute for Coastal and Marine Research, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Jonathan A Botha
- Marine Apex Predator Research Unit (MAPRU), Institute for Coastal and Marine Research, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, Victoria, Australia
| | - Scott Adams
- School of Engineering, Deakin University, Geelong, Victoria, Australia
| | - Charles A Bost
- Centre d'Études Biologiques de Chizé, UMR7372 CNRS/Univ La Rochelle, Villiers-en-Bois, France
| | - John P Y Arnould
- School of Life and Environmental Sciences, Faculty of Science & Technology, Deakin University, Burwood, Victoria, Australia
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22
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Zena LA, Dillon D, Hunt KE, Navas CA, Buck CL, Bícego KC. Hormonal correlates of the annual cycle of activity and body temperature in the South-American tegu lizard (Salvator merianae). Gen Comp Endocrinol 2020; 285:113295. [PMID: 31580883 DOI: 10.1016/j.ygcen.2019.113295] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/19/2019] [Accepted: 09/29/2019] [Indexed: 01/29/2023]
Abstract
Life history transitions and hormones are known to interact and influence many aspects of animal physiology and behavior. The South-American tegu lizard (Salvator merianae) exhibits a profound seasonal shift in metabolism and body temperature, characterized by high daily activity during warmer months, including reproductive endothermy in spring, and metabolic suppression during hibernation in winter. This makes S. merianae an interesting subject for studies of interrelationships between endocrinology and seasonal changes in physiology/behavior. We investigated how plasma concentrations of hormones involved in regulation of energy metabolism (thyroid hormones T4 and T3; corticosterone) and reproduction (testosterone in males and estrogen/progesterone in females) correlate with activity and body temperature (Tb) across the annual cycle of captive held S. merianae in semi-natural conditions. In our initial model, thyroid hormones and corticosterone showed a positive relationship with activity and Tb with independent of sex: T3 positively correlated with activity and Tb, while T4 and corticosterone correlated positively with changes in Tb only. This suggests that thyroid hormones and glucocorticoids may be involved in metabolic transitions of annual cycle events. When accounting for sex-steroid hormones, our sex separated models showed a positive relationship between testosterone and Tb in males and progesterone and activity in females. Coupling seasonal endocrine measures with activity and Tb may expand our understanding of the relationship between animal's physiology and its environment. Manipulative experiments are required in order to unveil the directionality of influences existing among abiotic factors and the hormonal signaling of annual cyclicity in physiology/behavior.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA, USA
| | - Carlos A Navas
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900 Jaboticabal, São Paulo, Brazil.
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23
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Shuert CR, Pomeroy PP, Twiss SD. Coping styles in capital breeders modulate behavioural trade-offs in time allocation: assessing fine-scale activity budgets in lactating grey seals (Halichoerus grypus) using accelerometry and heart rate variability. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2783-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
Balancing time allocation among competing behaviours is an essential part of energy management for all animals. However, trade-offs in time allocation may vary according to the sex of the individual, their age, and even underlying physiology. During reproduction, higher energetic demands and constrained internal resources place greater demand on optimizing these trade-offs insofar that small adjustments in time-activity may lead to substantial effects on an individual’s limited energy budget. The most extreme case is found in animals that undergo capital breeding, where individuals fast for the duration of each reproductive episode. We investigated potential underlying drivers of time-activity and describe aspects of trade-offs in time-activity in a wild, capital breeding pinniped, the grey seal Halichoerus grypus, during the lactation period. For the first time, we were able to access full 24-h activity budgets across the core duration of lactation as well as characterize how aspects of stress-coping styles influence time allocation through the use of animal-borne accelerometers and heart rate monitors in situ. We found that there was a distinct trade-off in time activity between time spent Resting and Alert (vigilance). This trade-off varied with the pup’s development, date, and maternal stress-coping style as indicated by a measure of heart rate variability, rMSSD. In contrast, time spent Presenting/Nursing did not vary across the duration of lactation given the variables tested. We suggest that while mothers balance time spent conserving resources (Resting) against time expending energy (Alert), they are also influenced by the inherent physiological drivers of stress-coping styles.
Significance statement
How animals apportion their time among different behaviours is key to their success. These trade-offs should be finely balanced to avoid unnecessary energy expenditure. Here, we examine how grey seal mothers balance their activity patterns during the short, but energetically demanding, period of pup-rearing. Animal-borne accelerometers provided a uniquely detailed and continuous record of activity during pup-rearing for 38 mothers. We also used heart rate monitors to provide measures of each individual’s stress-coping style. We found that mothers balance time Resting against remaining Alert while time Presenting/Nursing was largely independent of all factors measured. Stress-coping styles were found to drive the balancing and variation of all behaviours. This novel indication that differences in personality-like traits may drive whole activity budgets should be considered when assessing trade-offs in time allocation across a much wider variety of species.
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24
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Fahlbusch JA, Harrington KJ. A low-cost, open-source inertial movement GPS logger for eco-physiology applications. ACTA ACUST UNITED AC 2019; 222:jeb.211136. [PMID: 31753906 DOI: 10.1242/jeb.211136] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/15/2019] [Indexed: 11/20/2022]
Abstract
Open-source technology has been increasingly used for developing low-cost animal-borne bio-loggers; however, a gap remains for a bio-logger that records both inertial movement and GPS positions. We address this need with the Tapered Wings Logger (TWLogger), an archival bio-logger that records high-resolution (e.g. 50 Hz) tri-axial accelerometry and magnetometry, temperature and GPS. The TWLogger can be built for 90 USD, accepts user-defined sampling parameters, and with a 500 mA h battery weighs 25 g. We provide publicly available build instructions and custom analysis scripts. Bench tests recorded 50 Hz inertial movement and 2 min GPS for 31.8±2.2 h (mean±s.d., n=6) with GPS accuracy within 10.9±13.6 m. Field deployments on a medium-sized bird of prey in the wild achieved similar results (n=13). The customizable TWLogger has wide-ranging application across systems and thus offers a practical solution for eco-physiology applications.
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Affiliation(s)
- James A Fahlbusch
- Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA 93950, USA
| | - Katie J Harrington
- Acopian Center for Conservation Learning, Hawk Mountain Sanctuary, 410 Summer Valley Road, Orwigsburg, PA 17961, USA
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25
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Dujon AM, Stieglitz TC, Amice E, Webber DM. Snail leaps and bounds: drivers of the diel movement pattern of a large invertebrate, the Caribbean queen conch (Lobatus gigas), in a marginal inshore habitat. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Understanding the relationship between the movements of animals and their environment is crucial for fisheries and species management. There is currently a lack of detailed information about the movement of slow-moving benthic species, especially for species of ecological or commercial importance. Here we document the relationship between diel movement and environmental parameters in a groundwater-fed coastal inlet for the queen conch (Lobatus gigas (Linnaeus, 1758)), an important fishery resource of the Caribbean region, using three-dimensional accelerometers and video cameras. Our results show immature queen conch (n = 9) spend most of their active time grazing, exhibiting two main distinct movements that we characterize as a leap and a drift that are mostly used to access new foraging resources. When overturned, they flip, producing a movement with the highest acceleration recorded to limit exposure and restore normal position. Movement patterns appear to be significantly affected by the oxygen concentration of the bottom water, with lower activity during low-oxygen levels in the morning (probability of 0.75 of observing 0 movement per hour) and maximum activity during the afternoon when oxygen concentration is at its maximum (probability of 0.80 of observing >10 movements per hour). Salinity and temperature had little effect on movement patterns. Our results confirm that highly variable marginal habitats like groundwater-fed inlets are suitable for juvenile conch growth and should be included in efficient conservation plans.
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Affiliation(s)
- Antoine M. Dujon
- Laboratoire des Sciences de l’Environnement Marin – CNRS UMR 6539, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France
| | - Thomas C. Stieglitz
- Laboratoire des Sciences de l’Environnement Marin – CNRS UMR 6539, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France
- Centre for Tropical Water and Aquatic Ecosystem Research and School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811, Australia
| | - Erwan Amice
- Laboratoire des Sciences de l’Environnement Marin – CNRS UMR 6539, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France
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26
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Pagano AM, Williams TM. Estimating the energy expenditure of free-ranging polar bears using tri-axial accelerometers: A validation with doubly labeled water. Ecol Evol 2019; 9:4210-4219. [PMID: 31015999 PMCID: PMC6468055 DOI: 10.1002/ece3.5053] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/13/2019] [Accepted: 02/19/2019] [Indexed: 01/27/2023] Open
Abstract
Measures of energy expenditure can be used to inform animal conservation and management, but methods for measuring the energy expenditure of free-ranging animals have a variety of limitations. Advancements in biologging technologies have enabled the use of dynamic body acceleration derived from accelerometers as a proxy for energy expenditure. Although dynamic body acceleration has been shown to strongly correlate with oxygen consumption in captive animals, it has been validated in only a few studies on free-ranging animals. Here, we use relationships between oxygen consumption and overall dynamic body acceleration in resting and walking polar bears Ursus maritimus and published values for the costs of swimming in polar bears to estimate the total energy expenditure of 6 free-ranging polar bears that were primarily using the sea ice of the Beaufort Sea. Energetic models based on accelerometry were compared to models of energy expenditure on the same individuals derived from doubly labeled water methods. Accelerometer-based estimates of energy expenditure on average predicted total energy expenditure to be 30% less than estimates derived from doubly labeled water. Nevertheless, accelerometer-based measures of energy expenditure strongly correlated (r 2 = 0.70) with measures derived from doubly labeled water. Our findings highlight the strengths and limitations in dynamic body acceleration as a measure of total energy expenditure while also further supporting its use as a proxy for instantaneous, detailed energy expenditure in free-ranging animals.
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Affiliation(s)
- Anthony M. Pagano
- Alaska Science CenterU.S. Geological SurveyAnchorageAlaska
- Present address:
Institute for Conservation ResearchSan Diego Zoo GlobalSan DiegoCalifornia
| | - Terrie M. Williams
- Department of Ecology & Evolutionary BiologyUniversity of California, Santa CruzSanta CruzCalifornia
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27
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Heerah K, Cox SL, Blevin P, Guinet C, Charrassin JB. Validation of Dive Foraging Indices Using Archived and Transmitted Acceleration Data: The Case of the Weddell Seal. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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28
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Rojano-Doñate L, McDonald BI, Wisniewska DM, Johnson M, Teilmann J, Wahlberg M, Højer-Kristensen J, Madsen PT. High field metabolic rates of wild harbour porpoises. J Exp Biol 2018; 221:221/23/jeb185827. [DOI: 10.1242/jeb.185827] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/01/2018] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Reliable estimates of field metabolic rates (FMRs) in wild animals are essential for quantifying their ecological roles, as well as for evaluating fitness consequences of anthropogenic disturbances. Yet, standard methods for measuring FMR are difficult to use on free-ranging cetaceans whose FMR may deviate substantially from scaling predictions using terrestrial mammals. Harbour porpoises (Phocoena phocoena) are among the smallest marine mammals, and yet they live in cold, high-latitude waters where their high surface-to-volume ratio suggests high FMRs to stay warm. However, published FMR estimates of harbour porpoises are contradictory, with some studies claiming high FMRs and others concluding that the energetic requirements of porpoises resemble those of similar-sized terrestrial mammals. Here, we address this controversy using data from a combination of captive and wild porpoises to estimate the FMR of wild porpoises. We show that FMRs of harbour porpoises are up to two times greater than for similar-sized terrestrial mammals, supporting the hypothesis that small, carnivorous marine mammals in cold water have elevated FMRs. Despite the potential cost of thermoregulation in colder water, harbour porpoise FMRs are stable over seasonally changing water temperatures. Varying heat loss seems to be managed via cyclical fluctuations in energy intake, which serve to build up a blubber layer that largely offsets the extra costs of thermoregulation during winter. Such high FMRs are consistent with the recently reported high feeding rates of wild porpoises and highlight concerns about the potential impact of human activities on individual fitness and population dynamics.
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Affiliation(s)
- Laia Rojano-Doñate
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Birgitte I. McDonald
- Moss Landing Marine Laboratories, California State University, Moss Landing, CA 95039-9647, USA
| | | | - Mark Johnson
- Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Jonas Teilmann
- Marine Mammal Research, Department of Bioscience, Aarhus University, 4000 Roskilde, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
- Fjord&Bælt, 5300 Kerteminde, Denmark
| | | | - Peter T. Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
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29
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Ladds MA, Salton M, Hocking DP, McIntosh RR, Thompson AP, Slip DJ, Harcourt RG. Using accelerometers to develop time-energy budgets of wild fur seals from captive surrogates. PeerJ 2018; 6:e5814. [PMID: 30386705 PMCID: PMC6204822 DOI: 10.7717/peerj.5814] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 09/22/2018] [Indexed: 11/20/2022] Open
Abstract
Background Accurate time-energy budgets summarise an animal's energy expenditure in a given environment, and are potentially a sensitive indicator of how an animal responds to changing resources. Deriving accurate time-energy budgets requires an estimate of time spent in different activities and of the energetic cost of that activity. Bio-loggers (e.g., accelerometers) may provide a solution for monitoring animals such as fur seals that make long-duration foraging trips. Using low resolution to record behaviour may aid in the transmission of data, negating the need to recover the device. Methods This study used controlled captive experiments and previous energetic research to derive time-energy budgets of juvenile Australian fur seals (Arctocephalus pusillus) equipped with tri-axial accelerometers. First, captive fur seals and sea lions were equipped with accelerometers recording at high (20 Hz) and low (1 Hz) resolutions, and their behaviour recorded. Using this data, machine learning models were trained to recognise four states-foraging, grooming, travelling and resting. Next, the energetic cost of each behaviour, as a function of location (land or water), season and digestive state (pre- or post-prandial) was estimated. Then, diving and movement data were collected from nine wild juvenile fur seals wearing accelerometers recording at high- and low- resolutions. Models developed from captive seals were applied to accelerometry data from wild juvenile Australian fur seals and, finally, their time-energy budgets were reconstructed. Results Behaviour classification models built with low resolution (1 Hz) data correctly classified captive seal behaviours with very high accuracy (up to 90%) and recorded without interruption. Therefore, time-energy budgets of wild fur seals were constructed with these data. The reconstructed time-energy budgets revealed that juvenile fur seals expended the same amount of energy as adults of similar species. No significant differences in daily energy expenditure (DEE) were found across sex or season (winter or summer), but fur seals rested more when their energy expenditure was expected to be higher. Juvenile fur seals used behavioural compensatory techniques to conserve energy during activities that were expected to have high energetic outputs (such as diving). Discussion As low resolution accelerometry (1 Hz) was able to classify behaviour with very high accuracy, future studies may be able to transmit more data at a lower rate, reducing the need for tag recovery. Reconstructed time-energy budgets demonstrated that juvenile fur seals appear to expend the same amount of energy as their adult counterparts. Through pairing estimates of energy expenditure with behaviour this study demonstrates the potential to understand how fur seals expend energy, and where and how behavioural compensations are made to retain constant energy expenditure over a short (dive) and long (season) period.
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Affiliation(s)
- Monique A Ladds
- School of Mathematics and Statistics, Victoria University of Wellington, Wellington, New Zealand.,Marine Predator Research Group, Macquarie University, Sydney, New South Wales, Australia
| | - Marcus Salton
- Marine Predator Research Group, Macquarie University, Sydney, New South Wales, Australia
| | - David P Hocking
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Rebecca R McIntosh
- Marine Predator Research Group, Macquarie University, Sydney, New South Wales, Australia.,Research Department, Phillip Island Nature Parks, Phillip Island, Victoria, Australia
| | | | - David J Slip
- Marine Predator Research Group, Macquarie University, Sydney, New South Wales, Australia.,Taronga Conservation Society Australia, Sydney, New South Wales, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Macquarie University, Sydney, New South Wales, Australia
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30
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Isojunno S, Aoki K, Curé C, Kvadsheim PH, Miller PJO. Breathing Patterns Indicate Cost of Exercise During Diving and Response to Experimental Sound Exposures in Long-Finned Pilot Whales. Front Physiol 2018; 9:1462. [PMID: 30459631 PMCID: PMC6232938 DOI: 10.3389/fphys.2018.01462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/26/2018] [Indexed: 02/05/2023] Open
Abstract
Air-breathing marine predators that target sub-surface prey have to balance the energetic benefit of foraging against the time, energetic and physiological costs of diving. Here we use on-animal data loggers to assess whether such trade-offs can be revealed by the breathing rates (BR) and timing of breaths in long-finned pilot whales (Globicephela melas). We used the period immediately following foraging dives in particular, for which respiratory behavior can be expected to be optimized for gas exchange. Breath times and fluke strokes were detected using onboard sensors (pressure, 3-axis acceleration) attached to animals using suction cups. The number and timing of breaths were quantified in non-linear mixed models that incorporated serial correlation and individual as a random effect. We found that pilot whales increased their BR in the 5–10 min period prior to, and immediately following, dives that exceeded 31 m depth. While pre-dive BRs did not vary with dive duration, the initial post-dive BR was linearly correlated with duration of >2 min dives, with BR then declining exponentially. Apparent net diving costs were 1.7 (SE 0.2) breaths per min of diving (post-dive number of breaths, above pre-dive breathing rate unrelated to dive recovery). Every fluke stroke was estimated to cost 0.086 breaths, which amounted to 80–90% average contribution of locomotion to the net diving costs. After accounting for fluke stroke rate, individuals in the small body size class took a greater number of breaths per diving minute. Individuals reduced their breathing rate (from the rate expected by diving behavior) by 13–16% during playbacks of killer whale sounds and their first exposure to 1–2 kHz naval sonar, indicating similar responses to interspecific competitor/predator and anthropogenic sounds. Although we cannot rule out individuals increasing their per-breath O2 uptake to match metabolic demand, our results suggest that behavioral responses to experimental sound exposures were not associated with increased metabolic rates in a stress response, but metabolic rates instead appear to decrease. Our results support the hypothesis that maximal performance leads to predictable (optimized) breathing patterns, which combined with further physiological measurements could improve proxies of field metabolic rates and per-stroke energy costs from animal-borne behavior data.
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Affiliation(s)
- Saana Isojunno
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Kagari Aoki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | | | | | - Patrick James O'Malley Miller
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, United Kingdom
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31
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Chmura HE, Glass TW, Williams CT. Biologging Physiological and Ecological Responses to Climatic Variation: New Tools for the Climate Change Era. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00092] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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32
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Grémillet D, Lescroël A, Ballard G, Dugger KM, Massaro M, Porzig EL, Ainley DG. Energetic fitness: Field metabolic rates assessed via 3D accelerometry complement conventional fitness metrics. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13074] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- David Grémillet
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Université de Montpellier ‐ Université Paul‐Valéry Montpellier ‐ EPHE Montpellier France
- Percy FitzPatrick Institute and DST/NRF Excellence Centre at the University of Cape Town Rondebosch South Africa
| | - Amélie Lescroël
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Université de Montpellier ‐ Université Paul‐Valéry Montpellier ‐ EPHE Montpellier France
- Point Blue Conservation Science Petaluma CA USA
| | | | - Katie M. Dugger
- U.S. Geological Survey Oregon Cooperative Fish and Wildlife Research Unit Department of Fisheries and Wildlife, Oregon State University Corvallis OR USA
| | - Melanie Massaro
- School of Environmental Sciences Institute of Land, Water and Society Charles Sturt University Albury Australia
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33
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Cox SL, Orgeret F, Gesta M, Rodde C, Heizer I, Weimerskirch H, Guinet C, O'Hara RB. Processing of acceleration and dive data on-board satellite relay tags to investigate diving and foraging behaviour in free-ranging marine predators. Methods Ecol Evol 2018; 9:64-77. [PMID: 29456829 PMCID: PMC5812097 DOI: 10.1111/2041-210x.12845] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/06/2017] [Indexed: 11/29/2022]
Abstract
Biologging technologies are changing the way in which the marine environment is observed and monitored. However, because device retrieval is typically required to access the high-resolution data they collect, their use is generally restricted to those animals that predictably return to land. Data abstraction and transmission techniques aim to address this, although currently these are limited in scope and do not incorporate, for example, acceleration measurements which can quantify animal behaviours and movement patterns over fine-scales.In this study, we present a new method for the collection, abstraction and transmission of accelerometer data from free-ranging marine predators via the Argos satellite system. We test run the technique on 20 juvenile southern elephant seals Mirounga leonina from the Kerguelen Islands during their first months at sea following weaning. Using retrieved archival data from nine individuals that returned to the colony, we compare and validate abstracted transmissions against outputs from established accelerometer processing procedures.Abstracted transmissions included estimates, across five segments of a dive profile, of time spent in prey catch attempt (PrCA) behaviours, swimming effort and pitch. These were then summarised and compared to archival outputs across three dive phases: descent, bottom and ascent. Correlations between the two datasets were variable but generally good (dependent on dive phase, marginal R2 values of between .45 and .6 to >.9) and consistent between individuals. Transmitted estimates of PrCA behaviours and swimming effort were positively biased to those from archival processing.Data from this study represent some of the first remotely transmitted quantifications from accelerometers. The methods presented and analysed can be used to provide novel insight towards the behaviours and movements of free-ranging marine predators, such as juvenile southern elephant seals, from whom logger retrieval is challenging. Future applications could however benefit from some adaption, particularly to reduce positive bias in transmitted PrCA behaviours and swimming effort, for which this study provides useful insight.
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Affiliation(s)
- Sam L. Cox
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
| | - Florian Orgeret
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
| | - Mathieu Gesta
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
| | - Charles Rodde
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
| | | | - Henri Weimerskirch
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
| | - Christophe Guinet
- Centre d'Etudes Biologique de ChizéU.M.R. 7372 – CNRS & Universitié de La RochelleVilliers‐en‐BoisFrance
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34
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Ladds MA, Rosen DAS, Slip DJ, Harcourt RG. Proxies of energy expenditure for marine mammals: an experimental test of "the time trap". Sci Rep 2017; 7:11815. [PMID: 28924150 PMCID: PMC5603582 DOI: 10.1038/s41598-017-11576-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/23/2017] [Indexed: 11/25/2022] Open
Abstract
Direct measures of energy expenditure are difficult to obtain in marine mammals, and accelerometry may be a useful proxy. Recently its utility has been questioned as some analyses derived their measure of activity level by calculating the sum of accelerometry-based values and then comparing this summation to summed (total) energy expenditure (the so-called “time trap”). To test this hypothesis, we measured oxygen consumption of captive fur seals and sea lions wearing accelerometers during submerged swimming and calculated total and rate of energy expenditure. We compared these values with two potential proxies of energy expenditure derived from accelerometry data: flipper strokes and dynamic body acceleration (DBA). Total number of strokes, total DBA, and submergence time all predicted total oxygen consumption \documentclass[12pt]{minimal}
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\begin{document}$$({\boldsymbol{sV}}{{\boldsymbol{O}}}_{{\boldsymbol{2}}}$$\end{document}(sVO2 ml kg−1). However, both total DBA and total number of strokes were correlated with submergence time. Neither stroke rate nor mean DBA could predict the rate of oxygen consumption (\documentclass[12pt]{minimal}
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\begin{document}$$s\mathop{{\boldsymbol{V}}}\limits^{{\boldsymbol{.}}}{{\boldsymbol{O}}}_{{\boldsymbol{2}}}$$\end{document}sV.O2 ml min−1 kg−1). The relationship of total DBA and total strokes with total oxygen consumption is apparently a result of introducing a constant (time) into both sides of the relationship. This experimental evidence supports the conclusion that proxies derived from accelerometers cannot estimate the energy expenditure of marine mammals.
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Affiliation(s)
- Monique A Ladds
- School of Mathematics and Statistics, Victoria University of Wellington, Wellington, 6012, New Zealand. .,Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia.
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - David J Slip
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia.,Taronga Conservation Society Australia, Bradley's Head Road, Mosman, 2088, NSW, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia
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35
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Costantini D, Sebastiano M, Goossens B, Stark DJ. Jumping in the Night: An Investigation of the Leaping Activity of the Western Tarsier ( Cephalopachus bancanus borneanus) Using Accelerometers. Folia Primatol (Basel) 2017; 88:46-56. [DOI: 10.1159/000477540] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/12/2017] [Indexed: 12/19/2022]
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36
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Hicks O, Burthe S, Daunt F, Butler A, Bishop C, Green JA. Validating accelerometry estimates of energy expenditure across behaviours using heart rate data in a free-living seabird. J Exp Biol 2017; 220:1875-1881. [PMID: 28258086 PMCID: PMC5450806 DOI: 10.1242/jeb.152710] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/28/2017] [Indexed: 12/01/2022]
Abstract
Two main techniques have dominated the field of ecological energetics: the heart rate and doubly labelled water methods. Although well established, they are not without their weaknesses, namely expense, intrusiveness and lack of temporal resolution. A new technique has been developed using accelerometers; it uses the overall dynamic body acceleration (ODBA) of an animal as a calibrated proxy for energy expenditure. This method provides high-resolution data without the need for surgery. Significant relationships exist between the rate of oxygen consumption (V̇O2 ) and ODBA in controlled conditions across a number of taxa; however, it is not known whether ODBA represents a robust proxy for energy expenditure consistently in all natural behaviours and there have been specific questions over its validity during diving, in diving endotherms. Here, we simultaneously deployed accelerometers and heart rate loggers in a wild population of European shags (Phalacrocorax aristotelis). Existing calibration relationships were then used to make behaviour-specific estimates of energy expenditure for each of these two techniques. Compared with heart rate-derived estimates, the ODBA method predicts energy expenditure well during flight and diving behaviour, but overestimates the cost of resting behaviour. We then combined these two datasets to generate a new calibration relationship between ODBA and V̇O2 that accounts for this by being informed by heart rate-derived estimates. Across behaviours we found a good relationship between ODBA and V̇O2 Within individual behaviours, we found useable relationships between ODBA and V̇O2 for flight and resting, and a poor relationship during diving. The error associated with these new calibration relationships mostly originates from the previous heart rate calibration rather than the error associated with the ODBA method. The equations provide tools for understanding how energy constrains ecology across the complex behaviour of free-living diving birds.
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Affiliation(s)
- Olivia Hicks
- Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Sarah Burthe
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - Francis Daunt
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - Adam Butler
- Biomathematics and Statistics Scotland, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Charles Bishop
- School of Biological Sciences, Bangor University, Gwynedd LL57 2UW, UK
| | - Jonathan A Green
- Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
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37
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Reproductive success is energetically linked to foraging efficiency in Antarctic fur seals. PLoS One 2017; 12:e0174001. [PMID: 28453563 PMCID: PMC5409505 DOI: 10.1371/journal.pone.0174001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/01/2017] [Indexed: 11/29/2022] Open
Abstract
The efficiency with which individuals extract energy from their environment defines their survival and reproductive success, and thus their selective contribution to the population. Individuals that forage more efficiently (i.e., when energy gained exceeds energy expended) are likely to be more successful at raising viable offspring than individuals that forage less efficiently. Our goal was to test this prediction in large long-lived mammals under free-ranging conditions. To do so, we equipped 20 lactating Antarctic fur seals (Arctocephalus gazella) breeding on Kerguelen Island in the Southern Ocean with tags that recorded GPS locations, depth and tri-axial acceleration to determine at-sea behaviours and detailed time-activity budgets during their foraging trips. We also simultaneously measured energy spent at sea using the doubly-labeled water (DLW) method, and estimated the energy acquired while foraging from 1) type and energy content of prey species present in scat remains, and 2) numbers of prey capture attempts determined from head acceleration. Finally, we followed the growth of 36 pups from birth until weaning (of which 20 were the offspring of our 20 tracked mothers), and used the relative differences in body mass of pups at weaning as an index of first year survival and thus the reproductive success of their mothers. Our results show that females with greater foraging efficiencies produced relatively bigger pups at weaning. These mothers achieved greater foraging efficiency by extracting more energy per minute of diving rather than by reducing energy expenditure. This strategy also resulted in the females spending less time diving and less time overall at sea, which allowed them to deliver higher quality milk to their pups, or allowed their pups to suckle more frequently, or both. The linkage we demonstrate between reproductive success and the quality of individuals as foragers provides an individual-based quantitative framework to investigate how changes in the availability and accessibility of prey can affect fitness of animals.
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38
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Rosen DAS, Hindle AG, Gerlinsky CD, Goundie E, Hastie GD, Volpov BL, Trites AW. Physiological constraints and energetic costs of diving behaviour in marine mammals: a review of studies using trained Steller sea lions diving in the open ocean. J Comp Physiol B 2016; 187:29-50. [PMID: 27686668 DOI: 10.1007/s00360-016-1035-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 08/26/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
Abstract
Marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.
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Affiliation(s)
- David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Allyson G Hindle
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Carling D Gerlinsky
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Elizabeth Goundie
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Gordon D Hastie
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Beth L Volpov
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Andrew W Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
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