1
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Chevallay M, Guinet C, Goulet-Tran D, Jeanniard du Dot T. Sealing the deal - Antarctic fur seals' active hunting tactics to capture small evasive prey revealed by miniature sonar tags. J Exp Biol 2024; 227:jeb246937. [PMID: 38634142 DOI: 10.1242/jeb.246937] [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: 10/25/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024]
Abstract
The ability of predators to adopt hunting tactics that minimise escape reactions from prey is crucial for efficient foraging, and depends on detection capabilities and locomotor performance of both predators and prey. Here, we investigated the efficiency of a small pinniped, the Antarctic fur seal (Arctocephalus gazella) at exploiting their small prey by describing for the first time their fine-scale predator-prey interactions. We compared these with those from another diving predator, the southern elephant seal (Mirounga leonina) that forage on the same prey type. We used data recorded by a newly developed sonar tag that combines active acoustics with ultrahigh-resolution movement sensors to study simultaneously the fine-scale behaviour of both Antarctic fur seals and prey during predator-prey interactions in more than 1200 prey capture events for eight female Antarctic fur seals. Our results showed that Antarctic fur seals and their prey detect each other at the same time, i.e. 1-2 s before the strike, forcing Antarctic fur seals to display reactive fast-moving chases to capture their prey. In contrast, southern elephant seals detect their prey up to 10 s before the strike, allowing them to approach their prey stealthily without triggering an escape reaction. The active hunting tactics used by Antarctic fur seals is probably very energy consuming compared with the stalking tactics used by southern elephant seals but might be compensated for by the consumption of faster-moving larger prey. We suggest that differences in manoeuvrability, locomotor performance and detection capacities and in pace of life between Antarctic fur seals and southern elephant seals might explain these differences in hunting styles.
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Affiliation(s)
- Mathilde Chevallay
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
| | - Didier Goulet-Tran
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
| | - Tiphaine Jeanniard du Dot
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
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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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McGrosky A, Pontzer H. The fire of evolution: energy expenditure and ecology in primates and other endotherms. J Exp Biol 2023; 226:297166. [PMID: 36916459 DOI: 10.1242/jeb.245272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Total energy expenditure (TEE) represents the total energy allocated to growth, reproduction and body maintenance, as well as the energy expended on physical activity. Early experimental work in animal energetics focused on the costs of specific tasks (basal metabolic rate, locomotion, reproduction), while determination of TEE was limited to estimates from activity budgets or measurements of subjects confined to metabolic chambers. Advances in recent decades have enabled measures of TEE in free-living animals, challenging traditional additive approaches to understanding animal energy budgets. Variation in lifestyle and activity level can impact individuals' TEE on short time scales, but interspecific differences in TEE are largely shaped by evolution. Here, we review work on energy expenditure across the animal kingdom, with a particular focus on endotherms, and examine recent advances in primate energetics. Relative to other placental mammals, primates have low TEE, which may drive their slow pace of life and be an evolved response to the challenges presented by their ecologies and environments. TEE variation among hominoid primates appears to reflect adaptive shifts in energy throughput and allocation in response to ecological pressures. As the taxonomic breadth and depth of TEE data expand, we will be able to test additional hypotheses about how energy budgets are shaped by environmental pressures and explore the more proximal mechanisms that drive intra-specific variation in energy expenditure.
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Affiliation(s)
- Amanda McGrosky
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Herman Pontzer
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,Duke Global Health Institute, Durham, NC 27708, USA
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4
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Consoli FMA, Bernaldo de Quirós Y, Arbelo M, Fulle S, Marchisio M, Encinoso M, Fernandez A, Rivero MA. Cetaceans Humerus Radiodensity by CT: A Useful Technique Differentiating between Species, Ecophysiology, and Age. Animals (Basel) 2022; 12:ani12141793. [PMID: 35883340 PMCID: PMC9311750 DOI: 10.3390/ani12141793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
Cetaceans are mammals that underwent a series of evolutionary adaptations to live in the aquatic environment, including morphological modifications of various anatomical structures of the skeleton and their bone mineral density (BMD); there are few studies on the latter. BMD is related to the radiodensity measured through computed tomography (CT) in Hounsfield units (HU). This work aimed to test and validate the usefulness of studying humeral bone radiodensity by CT of two cetacean species (the Atlantic spotted dolphin and the pygmy sperm whale) with different swimming and diving habits. The radiodensity was analysed at certain levels following a new protocol based on a review of previous studies. Humeral radiodensity values were related to four aspects: species, diving behaviour, swimming activity level, and age. We observed that the consistent differences in the radiodensity of the cortical bone of the distal epiphysis between animals of different life-history categories suggest that this bone portion could be particularly useful for future ontogenetic studies. Hence, this technique may be helpful in studying and comparing species with different ecophysiologies, particularly distinguishing between swimming and diving habits.
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Affiliation(s)
- Francesco Maria Achille Consoli
- Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), University of Las Palmas de Gran Canaria (ULPGC), 35400 Las Palmas, Spain; (F.M.A.C.); (M.A.); (A.F.); (M.A.R.)
- Department of Neuroscience Imaging and Clinical Sciences, University G. D’Annunzio, 66100 Chieti, Italy;
| | - Yara Bernaldo de Quirós
- Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), University of Las Palmas de Gran Canaria (ULPGC), 35400 Las Palmas, Spain; (F.M.A.C.); (M.A.); (A.F.); (M.A.R.)
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80303, USA
- Correspondence:
| | - Manuel Arbelo
- Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), University of Las Palmas de Gran Canaria (ULPGC), 35400 Las Palmas, Spain; (F.M.A.C.); (M.A.); (A.F.); (M.A.R.)
| | - Stefania Fulle
- Department of Neuroscience Imaging and Clinical Sciences, University G. D’Annunzio, 66100 Chieti, Italy;
| | - Marco Marchisio
- Department of Medicine and Aging Sciences, Center for Advanced Studies and Technology (CAST), University G. D’Annunzio, 66100 Chieti, Italy;
| | - Mario Encinoso
- Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad de Las Palmas de Gran Canaria, 35413 Las Palmas, Spain;
| | - Antonio Fernandez
- Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), University of Las Palmas de Gran Canaria (ULPGC), 35400 Las Palmas, Spain; (F.M.A.C.); (M.A.); (A.F.); (M.A.R.)
| | - Miguel A. Rivero
- Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), University of Las Palmas de Gran Canaria (ULPGC), 35400 Las Palmas, Spain; (F.M.A.C.); (M.A.); (A.F.); (M.A.R.)
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5
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Hooker SK, Andrews RD, Arnould JPY, Bester MN, Davis RW, Insley SJ, Gales NJ, Goldsworthy SD, McKnight JC. Fur seals do, but sea lions don't - cross taxa insights into exhalation during ascent from dives. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200219. [PMID: 34121462 PMCID: PMC8200655 DOI: 10.1098/rstb.2020.0219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2020] [Indexed: 11/12/2022] Open
Abstract
Management of gases during diving is not well understood across marine mammal species. Prior to diving, phocid (true) seals generally exhale, a behaviour thought to assist with the prevention of decompression sickness. Otariid seals (fur seals and sea lions) have a greater reliance on their lung oxygen stores, and inhale prior to diving. One otariid, the Antarctic fur seal (Arctocephalus gazella), then exhales during the final 50-85% of the return to the surface, which may prevent another gas management issue: shallow-water blackout. Here, we compare data collected from animal-attached tags (video cameras, hydrophones and conductivity sensors) deployed on a suite of otariid seal species to examine the ubiquity of ascent exhalations for this group. We find evidence for ascent exhalations across four fur seal species, but that such exhalations are absent for three sea lion species. Fur seals and sea lions are no longer genetically separated into distinct subfamilies, but are morphologically distinguished by the thick underfur layer of fur seals. Together with their smaller size and energetic dives, we suggest their air-filled fur might underlie the need to perform these exhalations, although whether to reduce buoyancy and ascent speed, for the avoidance of shallow-water blackout or to prevent other cardiovascular management issues in their diving remains unclear. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.
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Affiliation(s)
- Sascha K. Hooker
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
| | | | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
| | - Marthán N. Bester
- Mammal Research Institute, University of Pretoria, Hatfield 0028, Gauteng, South Africa
| | - Randall W. Davis
- Department of Marine Biology, Texas A&M University, Galveston, TX 77553, USA
| | - Stephen J. Insley
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada, V8P 5C2
- Wildlife Conservation Society Canada, Whitehorse, Yukon Territory, Canada, Y1A 0E9
| | - Nick J. Gales
- Australian Antarctic Division, Kingston, Tasmania 7050, Australia
| | - Simon D. Goldsworthy
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - J. Chris McKnight
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
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6
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Williams CL, Czapanskiy MF, John JS, St Leger J, Scadeng M, Ponganis PJ. Cervical air sac oxygen profiles in diving emperor penguins: parabronchial ventilation and the respiratory oxygen store. J Exp Biol 2021; 224:jeb230219. [PMID: 33257430 DOI: 10.1242/jeb.230219] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/18/2020] [Indexed: 11/20/2022]
Abstract
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2 ) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2 values at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2 values were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not differ from prior estimates. The mean calculated anterior air sac O2 depletion rate for dives up to 11 min was approximately one-tenth that of the posterior air sacs. Low cervical air sac PO2 values at rest may be secondary to a low ratio of parabronchial ventilation to parabronchial blood O2 extraction. During dives, overlap of simultaneously recorded cervical and posterior thoracic air sac PO2 profiles supported the concept of maintenance of parabronchial ventilation during a dive by air movement through the lungs.
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Affiliation(s)
- Cassondra L Williams
- National Marine Mammal Foundation, 2240 Shelter Island Dr. #200, San Diego, CA 92106, USA
| | - Max F Czapanskiy
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950, USA
| | - Jason S John
- Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 McAlister Way, Santa Cruz, CA 95060, USA
| | - Judy St Leger
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
| | - Miriam Scadeng
- Department of Anatomy and Medical Imaging, Faculty of Health and Medical Sciences, University of Auckland, Auckland 1142, New Zealand
- Center for Functional Magnetic Resonance Imaging, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paul J Ponganis
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
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7
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Bauer U, Poppinga S, Müller UK. Mechanical Ecology-Taking Biomechanics to the Field. Integr Comp Biol 2020; 60:820-828. [PMID: 32275745 DOI: 10.1093/icb/icaa018] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Synopsis Interdisciplinary research can have strong and surprising synergistic effects, leading to rapid knowledge gains. Equally important, it can help to reintegrate fragmented fields across increasingly isolated specialist sub-disciplines. However, the lack of a common identifier for research "in between fields" can make it difficult to find relevant research outputs and network effectively. We illustrate and address this issue for the emerging interdisciplinary hotspot of "mechanical ecology," which we define here as the intersection of quantitative biomechanics and field ecology at the organism level. We show that an integrative approach crucially advances our understanding in both disciplines by (1) putting biomechanical mechanisms into a biologically meaningful ecological context and (2) addressing the largely neglected influence of mechanical factors in organismal and behavioral ecology. We call for the foundation of knowledge exchange platforms such as meeting symposia, special issues in journals, and focus groups dedicated to mechanical ecology.
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Affiliation(s)
- Ulrike Bauer
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Simon Poppinga
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany.,Freiburg Materials Research Center (FMF), University of Freiburg, Freiburg im Breisgau, Germany
| | - Ulrike K Müller
- Department of Biology, California State University Fresno, Fresno, CA, USA
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8
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McDonald BI, Tift MS, Hückstädt LA, Jeffko M, Ponganis PJ. Stroke effort and relative lung volume influence heart rate in diving sea lions. J Exp Biol 2020; 223:jeb214163. [PMID: 32098880 DOI: 10.1242/jeb.214163] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/10/2020] [Indexed: 11/20/2022]
Abstract
The dive response, bradycardia (decreased heart rate) and peripheral vasoconstriction, is the key mechanism allowing breath-hold divers to perform long-duration dives while actively swimming and hunting prey. This response is variable and modulated by factors such as dive duration, depth, exercise and cognitive control. This study assessed the potential role of exercise and relative lung volume in the regulation of heart rate (fH) during dives of adult female California sea lions instrumented with electrocardiogram (ECG), depth and tri-axial acceleration data loggers. A positive relationship between activity (minimum specific acceleration) and fH throughout dives suggested increased muscle perfusion associated with exercise. However, apart from late ascent, fH during dives was still less than or equal to resting fH (on land). In addition, the activity-fH relationship was weaker in long, deep dives consistent with prioritization of blood oxygen conservation over blood oxygen delivery to muscle in those dives. Pulmonary stretch receptor reflexes may also contribute to fH regulation as fH profiles generally paralleled changes in relative lung volume, especially in shallower dives and during early descent and late ascent of deeper dives. Overall, these findings support the concept that both exercise and pulmonary stretch receptor reflexes may influence the dive response in sea lions.
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Affiliation(s)
- Birgitte I McDonald
- Moss Landing Marine Laboratories, San Jose State University, 8272 Moss Landing Rd, Moss Landing, CA 95039, USA
| | - Michael S Tift
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Rd, Wilmington, NC 28403, USA
| | - Luis A Hückstädt
- Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - Michael Jeffko
- United States Coast Guard Academy, 27 Mohegan Way, New London, CT 06320, USA
| | - Paul J Ponganis
- Scripps Institution of Oceanography - University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
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9
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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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10
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Tift MS, Hückstädt LA, Ponganis PJ. Anterior vena caval oxygen profiles in a deep-diving California sea lion: arteriovenous shunts, a central venous oxygen store and oxygenation during lung collapse. ACTA ACUST UNITED AC 2018; 221:jeb.163428. [PMID: 29084854 DOI: 10.1242/jeb.163428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/26/2017] [Indexed: 11/20/2022]
Abstract
Deep-diving California sea lions (Zalophus californianus) can maintain arterial hemoglobin saturation (SO2 ) above 90% despite lung collapse (lack of gas exchange) and extremely low posterior vena caval SO2 in the middle of the dive. We investigated anterior vena caval PO2 and SO2 during dives of an adult female sea lion to investigate two hypotheses: (1) posterior vena caval SO2 is not representative of the entire venous oxygen store and (2) a well-oxygenated (arterialized) central venous oxygen reservoir might account for maintenance of arterial SO2 during lung collapse. During deep dives, initial anterior vena caval SO2 was elevated at 83.6±8.4% (n=102), presumably owing to arteriovenous shunting. It remained high until the bottom phase of the dive and then decreased during ascent, whereas previously determined posterior vena caval SO2 declined during descent and then often increased during ascent. These divergent patterns confirmed that posterior vena caval SO2 was not representative of the entire venous oxygen store. Prior to and early during descent of deep dives, the high SO2 values of both the anterior and posterior venae cavae may enhance arterialization of a central venous oxygen store. However, anterior vena caval SO2 values at depths beyond lung collapse reached levels as low as 40%, making it unlikely that even a completely arterialized central venous oxygen store could account for maintenance of high arterial SO2 These findings suggest that maintenance of high arterial SO2 during deep dives is due to persistence of some gas exchange at depths beyond presumed lung collapse.
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Affiliation(s)
- Michael S Tift
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biotechnology and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
| | - Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Laboratory, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Paul J Ponganis
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biotechnology and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
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11
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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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12
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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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Ladds MA, Rosen DA, Slip DJ, Harcourt RG. The utility of accelerometers to predict stroke rate in captive fur seals and sea lions. Biol Open 2017; 6:1396-1400. [PMID: 28798149 PMCID: PMC5612241 DOI: 10.1242/bio.027029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The energy expenditure of free-living fur seals and sea lions is difficult to measure directly, but may be indirectly derived from flipper stroke rate. We filmed 10 captive otariids swimming with accelerometers either attached to a harness (Daily Diary: sampling frequency 32 Hz, N=4) or taped to the fur (G6a+: 25 Hz, N=6). We used down sampling to derive four recording rates from each accelerometer (Daily Diary: 32, 16, 8, 4 Hz; G6a+: 25, 20, 10, 5 Hz). For each of these sampling frequencies, we derived 20 combinations of two parameters (RMW, the window size used to calculate the running mean; and m, the minimum number of points smaller than a local maxima used to detect a peak) from the dynamic acceleration of x, z and x+z, to estimate stroke rate from the accelerometers. These estimates differed by up to ∼20% in comparison to the actual number of foreflipper strokes counted from videos. RMW and the choice of axis used to make the calculations (x, z or x+z) had little effect on the overall differences, though the variability was reduced when using x+z. The best m varied depending on the axis used and the sampling frequency; a larger m was needed for higher sampling frequencies. This study demonstrates that when parameters are appropriately tuned, accelerometers are a simple yet valid tool for estimating the stroke rates of swimming otariids. Summary: Accelerometer data collected from captive fur seals and sea lions swimming were used to determine the best method for processing raw data to achieve the highest accuracy of stroke rate.
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Affiliation(s)
- Monique A Ladds
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia .,School of Mathematics and Statistics, Victoria University of Wellington, Wellington 6140, New Zealand
| | - David A Rosen
- Marine Mammal Research Unit, Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - David J Slip
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia.,Taronga Conservation Society Australia, Bradley's Head Road, Mosman, NSW 2088, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
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Wilson K, Littnan C, Halpin P, Read A. Integrating multiple technologies to understand the foraging behaviour of Hawaiian monk seals. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160703. [PMID: 28405358 PMCID: PMC5383815 DOI: 10.1098/rsos.160703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/06/2017] [Indexed: 05/15/2023]
Abstract
The objective of this research was to investigate and describe the foraging behaviour of monk seals in the main Hawaiian Islands. Specifically, our goal was to identify a metric to classify foraging behaviour from telemetry instruments. We deployed accelerometers, seal-mounted cameras and GPS tags on six monk seals during 2012-2014 on the islands of Molokai, Kauai and Oahu. We used pitch, calculated from the accelerometer, to identify search events and thus classify foraging dives. A search event and consequent 'foraging dive' occurred when the pitch was greater than or equal to 70° at a depth less than or equal to -3 m. By integrating data from the accelerometers with video and GPS, we were able to ground-truth this classification method and identify environmental variables associated with each foraging dive. We used Bayesian logistic regression to identify the variables that influenced search events. Dive depth, body motion (mean overall dynamic body acceleration during the dive) and proximity to the sea floor were the best predictors of search events for these seals. Search events typically occurred on long, deep dives, with more time spent at the bottom (more than 50% bottom time). We can now identify where monk seals are foraging in the main Hawaiian Islands (MHI) and what covariates influence foraging behaviour in this region. This increased understanding will inform management strategies and supplement outreach and recovery efforts.
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Affiliation(s)
- Kenady Wilson
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
- Author for correspondence: Kenady Wilson e-mail:
| | - Charles Littnan
- Pacific Island Fisheries Science Center, 1845 WASP Blvd., Building 176, Honolulu, HI 96818, USA
| | - Patrick Halpin
- Nicholas School of the Environment, Duke University, 9 Circuit Drive, Durham, NC 27708, USA
| | - Andrew Read
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
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Wilson K, Littnan C, Halpin P, Read A. Integrating multiple technologies to understand the foraging behaviour of Hawaiian monk seals. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160703. [PMID: 28405358 DOI: 10.5061/dryad.s0b80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/06/2017] [Indexed: 05/27/2023]
Abstract
The objective of this research was to investigate and describe the foraging behaviour of monk seals in the main Hawaiian Islands. Specifically, our goal was to identify a metric to classify foraging behaviour from telemetry instruments. We deployed accelerometers, seal-mounted cameras and GPS tags on six monk seals during 2012-2014 on the islands of Molokai, Kauai and Oahu. We used pitch, calculated from the accelerometer, to identify search events and thus classify foraging dives. A search event and consequent 'foraging dive' occurred when the pitch was greater than or equal to 70° at a depth less than or equal to -3 m. By integrating data from the accelerometers with video and GPS, we were able to ground-truth this classification method and identify environmental variables associated with each foraging dive. We used Bayesian logistic regression to identify the variables that influenced search events. Dive depth, body motion (mean overall dynamic body acceleration during the dive) and proximity to the sea floor were the best predictors of search events for these seals. Search events typically occurred on long, deep dives, with more time spent at the bottom (more than 50% bottom time). We can now identify where monk seals are foraging in the main Hawaiian Islands (MHI) and what covariates influence foraging behaviour in this region. This increased understanding will inform management strategies and supplement outreach and recovery efforts.
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Affiliation(s)
- Kenady Wilson
- Duke University Marine Lab , 135 Duke Marine Lab Rd, Beaufort, NC 28516 , USA
| | - Charles Littnan
- Pacific Island Fisheries Science Center , 1845 WASP Blvd., Building 176, Honolulu, HI 96818 , USA
| | - Patrick Halpin
- Nicholas School of the Environment , Duke University , 9 Circuit Drive, Durham, NC 27708 , USA
| | - Andrew Read
- Duke University Marine Lab , 135 Duke Marine Lab Rd, Beaufort, NC 28516 , USA
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Tift MS, Hückstädt LA, McDonald BI, Thorson PH, Ponganis PJ. Flipper stroke rate and venous oxygen levels in free-ranging California sea lions. ACTA ACUST UNITED AC 2017; 220:1533-1540. [PMID: 28167807 DOI: 10.1242/jeb.152314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/01/2017] [Indexed: 11/20/2022]
Abstract
The depletion rate of the blood oxygen store, development of hypoxemia and dive capacity are dependent on the distribution and rate of blood oxygen delivery to tissues while diving. Although blood oxygen extraction by working muscle would increase the blood oxygen depletion rate in a swimming animal, there is little information on the relationship between muscle workload and blood oxygen depletion during dives. Therefore, we examined flipper stroke rate, a proxy of muscle workload, and posterior vena cava oxygen profiles in four adult female California sea lions (Zalophus californianus) during foraging trips at sea. Flipper stroke rate analysis revealed that sea lions minimized muscle metabolism with a stroke-glide strategy when diving, and exhibited prolonged glides during the descent of deeper dives (>100 m). During the descent phase of these deep dives, 55±21% of descent was spent gliding, with the longest glides lasting over 160 s and covering a vertical distance of 340 m. Animals also consistently glided to the surface from 15 to 25 m depth during these deeper dives. Venous hemoglobin saturation (SO2 ) profiles were highly variable throughout dives, with values occasionally increasing during shallow dives. The relationship between SO2 and flipper stroke rate was weak during deeper dives, while this relationship was stronger during shallow dives. We conclude that (1) the depletion of oxygen in the posterior vena cava in deep-diving sea lions is not dependent on stroke effort, and (2) stroke-glide patterns during dives contribute to a reduction of muscle metabolic rate.
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Affiliation(s)
- Michael S Tift
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
| | - Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Lab, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Birgitte I McDonald
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA
| | - Philip H Thorson
- Institute of Marine Sciences, University of California Santa Cruz, Long Marine Laboratory, 100 Shaffer Road, CA 95060, USA
| | - Paul J Ponganis
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
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Halsey LG. Relationships grow with time: a note of caution about energy expenditure‐proxy correlations, focussing on accelerometry as an example. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12822] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lewis G. Halsey
- University of Roehampton Holybourne Avenue LondonSW15 4JD UK
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