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Berry P, Dammhahn M, Hauptfleisch M, Hering R, Jansen J, Kraus A, Blaum N. African dryland antelope trade-off behaviours in response to heat extremes. Ecol Evol 2024; 14:e11455. [PMID: 38855312 PMCID: PMC11157150 DOI: 10.1002/ece3.11455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/30/2024] [Accepted: 05/07/2024] [Indexed: 06/11/2024] Open
Abstract
Climate change is predicted to narrow the prescriptive zone of dryland species, potentially leading to behavioural modifications with fitness consequences. This study explores the behavioural responses of three widespread African antelope species-springbok, kudu and eland-to extreme heat in a dryland savanna. We classified the behaviour of 29 individuals during the hot, dry season on the basis of accelerometer data using supervised machine learning and analysed the impact of afternoon heat on behaviour-specific time allocation and overall dynamic body acceleration (ODBA), a proxy for energy expenditure, along with compensatory changes over the 24-hour cycle. Extreme afternoon heat reduced feeding time in all three antelope species, increased ruminating and resting time, while only minimally affecting walking time. With rising heat, all three species reduced ODBA on feeding, while eland reduced and kudu increased ODBA on walking. Diel responses in behaviour differed between species, but were generally characterised by daytime reductions in feeding and increases in ruminating or resting on hot days compared to cool days. While antelope compensated for heat-driven behavioural change over the 24-hour cycle in some cases, significant differences persisted in others, including reduced feeding and increased rumination and resting. The impact of heat on antelope behaviour reveals trade-offs between feeding and thermoregulation, as well as between feeding and rumination, the latter suggesting a strategy to enhance nutrient uptake through increased digestive efficiency, while the walking response suggests narrow constraints between cost and necessity. Our findings suggest that heat influences both behaviour-specific time allocation and energy expenditure. Altered diel behaviour patterns and incomplete compensation over the 24-hour cycle point to fitness consequences. The need to prioritise thermoregulation over feeding is likely to narrow the prescriptive zone of these dryland antelope.
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Affiliation(s)
- Paul Berry
- Plant Ecology and Nature Conservation, Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Melanie Dammhahn
- Behavioural Biology, Institute for Neuro‐ and Behavioural Biology (INVB)University of MünsterMünsterGermany
| | - Morgan Hauptfleisch
- Research DirectorateNamibia Nature FoundationWindhoekNamibia
- Unit for Environmental Sciences and ManagementNorth West UniversityPotchefstroomNort West ProvinceSouth Africa
- Biodiversity Research CentreNamibia University of Science and TechnologyWindhoekNamibia
| | - Robert Hering
- Ecology/Macroecology, Institute of Biochemsitry and BiologyUniversity of PotsdamPotsdamGermany
| | - Jakob Jansen
- Plant Ecology and Nature Conservation, Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Anna Kraus
- Plant Ecology and Nature Conservation, Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Niels Blaum
- Plant Ecology and Nature Conservation, Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
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2
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Garcia-Parraga D, Crespo-Picazo JL, Sterba-Boatwright B, Marco V, Muñoz-Baquero M, Robinson NJ, Stacy B, Fahlman A. New insights into risk variables associated with gas embolism in loggerhead sea turtles ( Caretta caretta) caught in trawls and gillnets. CONSERVATION PHYSIOLOGY 2023; 11:coad048. [PMID: 37425482 PMCID: PMC10326834 DOI: 10.1093/conphys/coad048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 06/02/2023] [Accepted: 06/26/2023] [Indexed: 07/11/2023]
Abstract
Tissue and blood gas embolism (GE) associated with fisheries bycatch are likely a widespread, yet underestimated, cause of sea turtle mortality. Here, we evaluated risk factors associated with tissue and blood GE in loggerhead turtles caught incidentally by trawl and gillnet fisheries on the Valencian coastline of Spain. Of 413 turtles (303 caught by trawl, 110 by gillnet fisheries), 54% (n = 222) exhibited GE. For sea turtles caught in trawls, the probability and severity of GE increased with trawl depth and turtle body mass. In addition, trawl depth and the GE score together explained the probability of mortality (P[mortality]) following recompression therapy. Specifically, a turtle with a GE score of 3 caught in a trawl deployed at 110 m had a P[mortality] of ~50%. For turtles caught in gillnets, no risk variables were significantly correlated with either the P[GE] or GE score. However, gillnet depth or GE score, separately, explained P[mortality], and a turtle caught at 45 m or with a GE score between 3 and 4 had a P[mortality] of 50%. Differences in the fishery characteristics precluded direct comparison of GE risk and mortality between these gear types. Although P[mortality] is expected to be significantly higher in untreated turtles released at sea, our findings can improve estimates of sea turtle mortality associated with trawls and gillnets, and help guide associate conservation efforts.
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Affiliation(s)
- Daniel Garcia-Parraga
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Jose Luis Crespo-Picazo
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | | | - Vicente Marco
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Marta Muñoz-Baquero
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Nathan J Robinson
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
- Institut de Ciències del Mar, Spanish National Research Council - Consejo Superior de Investigaciones Científicas, Barcelona 08003, Spain
| | - Brian Stacy
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, University of Florida (Duty Station), PO Box 110885, 2187 Mowry Road, Gainesville, FL 32611, USA
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Jeantet L, Hadetskyi V, Vigon V, Korysko F, Paranthoen N, Chevallier D. Estimation of the Maternal Investment of Sea Turtles by Automatic Identification of Nesting Behavior and Number of Eggs Laid from a Tri-Axial Accelerometer. Animals (Basel) 2022; 12:ani12040520. [PMID: 35203228 PMCID: PMC8868198 DOI: 10.3390/ani12040520] [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: 01/19/2022] [Revised: 02/13/2022] [Accepted: 02/16/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary During the reproduction period, female sea turtles come several times onto the beaches to lay their eggs. Monitoring of the nesting populations is therefore important to estimate the state of a population and its future. However, measuring the clutch size and frequency of sea turtles is tedious work that requires rigorous monitoring of the nesting site throughout the breeding season. In order to support the fieldwork, we propose an automatic method to remotely record the behavior on land of the sea turtles from animal-attached sensors; an accelerometer. The proposed method estimates, with an accuracy of 95%, the behaviors on land of sea turtles and the number of eggs laid. This automatic method should therefore help researchers monitor nesting sea turtle populations and contribute to improving global knowledge on the demographic status of these threatened species. Abstract Monitoring reproductive outputs of sea turtles is difficult, as it requires a large number of observers patrolling extended beaches every night throughout the breeding season with the risk of missing nesting individuals. We introduce the first automatic method to remotely record the reproductive outputs of green turtles (Chelonia mydas) using accelerometers. First, we trained a fully convolutional neural network, the V-net, to automatically identify the six behaviors shown during nesting. With an accuracy of 0.95, the V-net succeeded in detecting the Egg laying process with a precision of 0.97. Then, we estimated the number of laid eggs from the predicted Egg laying sequence and obtained the outputs with a mean relative error of 7% compared to the observed numbers in the field. Based on deployment of non-invasive and miniature loggers, the proposed method should help researchers monitor nesting sea turtle populations. Furthermore, its use can be coupled with the deployment of accelerometers at sea during the intra-nesting period, from which behaviors can also be estimated. The knowledge of the behavior of sea turtle on land and at sea during the entire reproduction period is essential to improve our knowledge of this threatened species.
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Affiliation(s)
- Lorène Jeantet
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France;
- Correspondence:
| | - Vadym Hadetskyi
- UFR Math-Info, Université de Strasbourg, 7 rue Descartes, CEDEX, 67081 Strasbourg, France; (V.H.); (V.V.)
| | - Vincent Vigon
- UFR Math-Info, Université de Strasbourg, 7 rue Descartes, CEDEX, 67081 Strasbourg, France; (V.H.); (V.V.)
| | - François Korysko
- Office Français de la Biodiversité, Direction des Outre-mer, Délégation Guyane, 44 rue Pasteur, BP 10808, 97338 Cayenne, France; (F.K.); (N.P.)
| | - Nicolas Paranthoen
- Office Français de la Biodiversité, Direction des Outre-mer, Délégation Guyane, 44 rue Pasteur, BP 10808, 97338 Cayenne, France; (F.K.); (N.P.)
| | - Damien Chevallier
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France;
- BOREA Research Unit, National Museum of Natural History (MNHN), UMR CNRS 7208, Sorbonne Université, French Institute for Research and Development (IRD 207), University of Caen Normandie, University of Antilles, CEDEX 05, 75231 Paris, France
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Ascarrunz E, Sánchez-Villagra MR. The macroevolutionary and developmental evolution of the turtle carapacial scutes. VERTEBRATE ZOOLOGY 2022. [DOI: 10.3897/vz.72.e76256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The scutes of the carapace of extant turtles exhibit common elements in a narrow range of topographical arrangements. The typical arrangement has remained constant since its origin in the clade Mesochelydia (Early Jurassic), after a period of apparent greater diversity in the Triassic. This contribution is a review of the development and evolutionary history of the scute patterns of the carapace, seen through the lens of recent developmental models. This yields insights on pattern variations in the fossil record. We reinterpret the “supracaudal” scute and propose that Proganochelys had five vertebral scutes. We discuss the relationship between supramarginal scutes and Turing processes, and we show how a simple change during embryogenesis could account for origin of the configuration of the caudal region of the carapace in mesochelydians. We also discuss the nature of the decrease in number of scutes over the course of evolution, and whether macroevolutionary trends can be discerned. We argue that turtles with complete loss of scutes (e.g., softshells) follow clade-specific macroevolutionary regimes, which are distinct from the majority of other turtles. Finally, we draw a parallel between the variation of scute patterns on the carapace of turtles and the scale patterns in the pileus region (roof of the head) of squamates. The size and numbers of scales in the pileus region can evolve over a wide range, but we recognized tentative evidence of convergence towards a typical configuration when the scales become larger and fewer. Thus, typical patterns could be a more general property of similar systems of integumentary appendages.
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5
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Analysis of risk factors associated with gas embolism and evaluation of predictors of mortality in 482 loggerhead sea turtles. Sci Rep 2021; 11:22693. [PMID: 34811412 PMCID: PMC8608947 DOI: 10.1038/s41598-021-02017-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/08/2021] [Indexed: 11/08/2022] Open
Abstract
Sea turtles that are entrapped in static and towed nets may develop gas embolism which can lead to severe organ injury and death. Trawling characteristics, physical and physiologic factors associated with gas-embolism and predictors of mortality were analysed from 482 bycaught loggerheads. We found 204 turtles affected by gas-embolism and significant positive correlations between the presence of gas-embolism and duration, depth, ascent rate of trawl, turtle size and temperature, and between mortality and ascent time, neurological deficits, significant acidosis and involvement of > 12 cardiovascular sites and the left atrium and sinus venosus-right atrium. About 90% turtles with GE alive upon arrival at Sea Turtle Clinic recovered from the disease without any supportive drug therapy. Results of this study may be useful in clinical evaluation, prognostication, and management for turtles affected by gas-embolism, but bycatch reduction must become a priority for major international organizations. According to the results of the present study the measures to be considered to reduce the catches or mortality of sea turtles for trawling are to be found in the modification of fishing nets or fishing operations and in greater awareness and education of fishermen.
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Robinson NJ, García-Párraga D, Stacy BA, Costidis AM, Blanco GS, Clyde-Brockway CE, Haas HL, Harms CA, Patel SH, Stacy NI, Fahlman A. A Baseline Model For Estimating the Risk of Gas Embolism in Sea Turtles During Routine Dives. Front Physiol 2021; 12:678555. [PMID: 34539425 PMCID: PMC8440993 DOI: 10.3389/fphys.2021.678555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Sea turtles, like other air-breathing diving vertebrates, commonly experience significant gas embolism (GE) when incidentally caught at depth in fishing gear and brought to the surface. To better understand why sea turtles develop GE, we built a mathematical model to estimate partial pressures of N2 (PN2), O2 (PO2), and CO2 (PCO2) in the major body-compartments of diving loggerheads (Caretta caretta), leatherbacks (Dermochelys coriacea), and green turtles (Chelonia mydas). This model was adapted from a published model for estimating gas dynamics in marine mammals and penguins. To parameterize the sea turtle model, we used values gleaned from previously published literature and 22 necropsies. Next, we applied this model to data collected from free-roaming individuals of the three study species. Finally, we varied body-condition and cardiac output within the model to see how these factors affected the risk of GE. Our model suggests that cardiac output likely plays a significant role in the modulation of GE, especially in the deeper diving leatherback turtles. This baseline model also indicates that even during routine diving behavior, sea turtles are at high risk of GE. This likely means that turtles have additional behavioral, anatomical, and/or physiologic adaptions that serve to reduce the probability of GE but were not incorporated in this model. Identifying these adaptations and incorporating them into future iterations of this model will further reveal the factors driving GE in sea turtles.
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Affiliation(s)
- Nathan J. Robinson
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
| | - Daniel García-Párraga
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
| | - Brian A. Stacy
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, University of Florida (duty station), Washington, DC, United States
| | | | - Gabriela S. Blanco
- Instituto de Biología de Organismos Marinos (IBIOMAR-CCT CONICET-CENPAT), Puerto Madryn, Argentina
| | | | - Heather L. Haas
- Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Woods Hole, MA, United States
| | - Craig A. Harms
- Department of Clinical Sciences and Center for Marine Sciences and Technology, North Carolina State University, Raleigh, NC, United States
| | - Samir H. Patel
- Coonamessett Farm Foundation, East Falmouth, MA, United States
| | - Nicole I. Stacy
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Andreas Fahlman
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
- Global Diving Research, Inc., Ottawa, ON, Canada
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7
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Gunner RM, Wilson RP, Holton MD, Scott R, Arkwright A, Fahlman A, Ulrich M, Hopkins P, Duarte C, Eizaguirre C. Activity of loggerhead turtles during the U-shaped dive: insights using angular velocity metrics. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Understanding the behavioural ecology of endangered taxa can inform conservation strategies. The activity budgets of the loggerhead turtle Caretta caretta are still poorly understood because many tracking methods show only horizontal displacement and ignore dives and associated behaviours. However, time-depth recorders have enabled researchers to identify flat, U-shaped dives (or type 1a dives) and these are conventionally labelled as resting dives on the seabed because they involve no vertical displacement of the animal. Video- and acceleration-based studies have demonstrated this is not always true. Focusing on sea turtles nesting on the Cabo Verde archipelago, we describe a new metric derived from magnetometer data, absolute angular velocity, that integrates indices of angular rotation in the horizontal plane to infer activity. Using this metric, we evaluated the variation in putative resting behaviours during the bottom phase of type 1a dives for 5 individuals over 13 to 17 d at sea during a single inter-nesting interval (over 75 turtle d in total). We defined absolute resting within the bottom phase of type 1a dives as periods with no discernible acceleration or angular movement. Whilst absolute resting constituted a significant proportion of each turtle’s time budget for this 1a dive type, turtles allocated 16-38% of their bottom time to activity, with many dives being episodic, comprised of intermittent bouts of rest and rotational activity. This implies that previously considered resting behaviours are complex and need to be accounted for in energy budgets, particularly since energy budgets may impact conservation strategies.
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Affiliation(s)
- RM Gunner
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - RP Wilson
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - MD Holton
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - R Scott
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
- Natural Environmental Research Council, Polaris House, North Star Avenue, Swindon SN2 1FL, UK
| | - A Arkwright
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
- L’Oceanogràfic, Ciutat de les Arts i de les Ciències, Carrer d’Eduardo Primo Yúfera, 1B, 46013 Valencia, Spain
| | - A Fahlman
- L’Oceanogràfic, Ciutat de les Arts i de les Ciències, Carrer d’Eduardo Primo Yúfera, 1B, 46013 Valencia, Spain
| | - M Ulrich
- Institutionen för fysik kemi och biologi (IFM), Linköping Universitet, Olaus Magnus väg, 583 30 Linköping, Sweden
| | - P Hopkins
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - C Duarte
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - C Eizaguirre
- School of Biological and Chemical Sciences, Queen Mary University of London, London E35SA, UK
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8
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Okuyama J, Benson SR, Dutton PH, Seminoff JA. Changes in dive patterns of leatherback turtles with sea surface temperature and potential foraging habitats. Ecosphere 2021. [DOI: 10.1002/ecs2.3365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Junichi Okuyama
- Marine Mammal and Turtle Division Southwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration La Jolla California92037USA
| | - Scott R. Benson
- Marine Mammal and Turtle Division Southwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Moss Landing California95039USA
- Moss Landing Marine Laboratories Moss Landing California95039USA
| | - Peter H. Dutton
- Marine Mammal and Turtle Division Southwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration La Jolla California92037USA
| | - Jeffrey A. Seminoff
- Marine Mammal and Turtle Division Southwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration La Jolla California92037USA
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9
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Páez-Rosas D, Salinas-de-León P, Proaño A, Vaca-Pita L, Suarez-Moncada J. Multi-tissue stable isotope analyses reveal temporal changes in the feeding patterns of green turtles in the Galapagos Marine Reserve. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:319-328. [PMID: 33481356 DOI: 10.1002/jez.2444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/24/2020] [Accepted: 12/26/2020] [Indexed: 11/07/2022]
Abstract
Knowledge of feeding patterns of highly migratory species is critical for understanding their habitat use and informing the management of their populations. The Galapagos Islands are one of the most important nesting and feeding areas for green turtles (Chelonia mydas) across the tropical eastern Pacific, yet little is known about the feeding patterns of this species. The isotopic composition of different tissues has been used to gain insight into the trophic dynamics of mobile aquatic consumers whose trophic behavior is difficult to directly measure. To elucidate the temporal feeding patterns and isotopic niche sizes of Galapagos green turtles, stable isotope analyses were performed on multiple tissues (skin and carapace) collected at the two most important nesting areas in the archipelago: Bachas and Quinta Playa. The δ13 C and δ15 N signatures on the skin and carapace samples from 56 adult females revealed significant differences between tissues (p = .001 and p = .021, respectively) and nesting areas (p = .011 and p = .003, respectively). These differences suggest a shift from oceanic feeding grounds to neritic habitats before nesting. The carapace isotope values indicated an offshore feeding strategy and a greater isotopic niche (SEAc = 1.91‰2 ), whereas the skin isotope values represented an inshore feeding strategy with a narrower niche (SEAc = 1.37‰2 ), likely related to the consumption of specific coastal prey. Our results suggest that Galapagos green turtles feed across different habitats, and this information can be applied to improve the management of this endangered species.
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Affiliation(s)
- Diego Páez-Rosas
- Galapagos Science Center, Universidad San Francisco de Quito, Isla San Cristóbal, Islas Galápagos, Ecuador
| | - Pelayo Salinas-de-León
- Fundación Charles Darwin, Charles Darwin Research Station, Isla Santa Cruz, Islas Galápagos, Ecuador.,Pristine Seas, National Geographic Society, Washington, District of Columbia, USA
| | - Alberto Proaño
- Departamento de Ecosistemas Marinos, Dirección Parque Nacional Galápagos, Isla Santa Cruz, Islas Galápagos, Ecuador
| | - Leandro Vaca-Pita
- Galapagos Science Center, Universidad San Francisco de Quito, Isla San Cristóbal, Islas Galápagos, Ecuador
| | - Jenifer Suarez-Moncada
- Departamento de Ecosistemas Marinos, Dirección Parque Nacional Galápagos, Isla Santa Cruz, Islas Galápagos, Ecuador
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Arango BG, Harfush-Meléndez M, Marmolejo-Valencia JA, Merchant-Larios H, Crocker DE. Blood oxygen stores of olive ridley sea turtles, Lepidochelys olivacea are highly variable among individuals during arribada nesting. J Comp Physiol B 2020; 191:185-194. [PMID: 33064209 DOI: 10.1007/s00360-020-01321-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 09/14/2020] [Accepted: 09/29/2020] [Indexed: 11/25/2022]
Abstract
Sea turtles dive with a full lung of air and these O2 stores are supplemented by O2 stored in blood and muscle. Olive ridley sea turtles exhibit polymorphic nesting behavior, mass nesting behavior called arribada, where thousands of turtles will nest at once, and solitary nesting behavior. The potential physiological differences between the individuals using these strategies are not well understood. We measured blood volume and associated variables, including blood hemoglobin content and hematocrit, to estimate total blood O2 stores. There were no significant differences in mean values between nesting strategies, but arribada nesting individuals were more variable than those performing solitary nesting. Mass-specific plasma volume was relatively invariant among individuals but mass specific blood volume and blood oxygen stores varied widely, twofold and threefold, respectively. Blood O2 stores represented 32% of total body O2 stores. Under typical mean diving conditions of 26 °C and high levels of activity, blood stores confer ~ 14 min to aerobic dive times and are likely critical for the long duration, deep diving exhibited by the species. Individual differences in blood O2 stores strongly impact estimated aerobic dive limits and may constrain the ability of individuals to respond to changes on ocean climate.
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Affiliation(s)
- B Gabriela Arango
- Biology Department, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA, 94928, USA.
| | | | | | - Horacio Merchant-Larios
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - Daniel E Crocker
- Biology Department, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA, 94928, USA
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Favilla AB, Costa DP. Thermoregulatory Strategies of Diving Air-Breathing Marine Vertebrates: A Review. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.555509] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Jeantet L, Planas-Bielsa V, Benhamou S, Geiger S, Martin J, Siegwalt F, Lelong P, Gresser J, Etienne D, Hiélard G, Arque A, Regis S, Lecerf N, Frouin C, Benhalilou A, Murgale C, Maillet T, Andreani L, Campistron G, Delvaux H, Guyon C, Richard S, Lefebvre F, Aubert N, Habold C, le Maho Y, Chevallier D. Behavioural inference from signal processing using animal-borne multi-sensor loggers: a novel solution to extend the knowledge of sea turtle ecology. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200139. [PMID: 32537218 PMCID: PMC7277266 DOI: 10.1098/rsos.200139] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/17/2020] [Indexed: 06/10/2023]
Abstract
The identification of sea turtle behaviours is a prerequisite to predicting the activities and time-budget of these animals in their natural habitat over the long term. However, this is hampered by a lack of reliable methods that enable the detection and monitoring of certain key behaviours such as feeding. This study proposes a combined approach that automatically identifies the different behaviours of free-ranging sea turtles through the use of animal-borne multi-sensor recorders (accelerometer, gyroscope and time-depth recorder), validated by animal-borne video-recorder data. We show here that the combination of supervised learning algorithms and multi-signal analysis tools can provide accurate inferences of the behaviours expressed, including feeding and scratching behaviours that are of crucial ecological interest for sea turtles. Our procedure uses multi-sensor miniaturized loggers that can be deployed on free-ranging animals with minimal disturbance. It provides an easily adaptable and replicable approach for the long-term automatic identification of the different activities and determination of time-budgets in sea turtles. This approach should also be applicable to a broad range of other species and could significantly contribute to the conservation of endangered species by providing detailed knowledge of key animal activities such as feeding, travelling and resting.
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Affiliation(s)
- Lorène Jeantet
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Víctor Planas-Bielsa
- Centre Scientifique de Monaco, Département de Biologie Polaire, 8 quai Antoine Ier, MC 98000Monaco
| | - Simon Benhamou
- Centre d’Écologie Fonctionnelle et Évolutive, CNRS, Montpellier, France & Cogitamus Lab
| | - Sebastien Geiger
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Jordan Martin
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Flora Siegwalt
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Pierre Lelong
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Julie Gresser
- DEAL Martinique, Pointe de Jaham, BP 7212, 97274 Schoelcher Cedex, France
| | - Denis Etienne
- DEAL Martinique, Pointe de Jaham, BP 7212, 97274 Schoelcher Cedex, France
| | - Gaëlle Hiélard
- Office de l'Eau Martinique, 7 Avenue Condorcet, BP 32, 97201 Fort-de-France, Martinique, France
| | - Alexandre Arque
- Office de l'Eau Martinique, 7 Avenue Condorcet, BP 32, 97201 Fort-de-France, Martinique, France
| | - Sidney Regis
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Nicolas Lecerf
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Cédric Frouin
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | | | - Céline Murgale
- Association POEMM, 73 lot papayers, Anse a l'âne, 97229 Les Trois Ilets, Martinique
| | - Thomas Maillet
- Association POEMM, 73 lot papayers, Anse a l'âne, 97229 Les Trois Ilets, Martinique
| | - Lucas Andreani
- Association POEMM, 73 lot papayers, Anse a l'âne, 97229 Les Trois Ilets, Martinique
| | - Guilhem Campistron
- Association POEMM, 73 lot papayers, Anse a l'âne, 97229 Les Trois Ilets, Martinique
| | - Hélène Delvaux
- DEAL Guyane, Rue Carlos Finley, CS 76003, 97306 Cayenne Cedex, France
| | - Christelle Guyon
- DEAL Guyane, Rue Carlos Finley, CS 76003, 97306 Cayenne Cedex, France
| | - Sandrine Richard
- Centre National d'Etudes Spatiales, Centre Spatial Guyanais, BP 726, 97387 Kourou Cedex, Guyane
| | - Fabien Lefebvre
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Nathalie Aubert
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Caroline Habold
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
| | - Yvon le Maho
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
- Centre Scientifique de Monaco, Département de Biologie Polaire, 8 quai Antoine Ier, MC 98000Monaco
| | - Damien Chevallier
- Institut Pluridisciplinaire Hubert Curien, CNRS–Unistra, 67087 Strasbourg, France
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13
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Jeantet L, Dell'Amico F, Forin-Wiart MA, Coutant M, Bonola M, Etienne D, Gresser J, Regis S, Lecerf N, Lefebvre F, de Thoisy B, Le Maho Y, Brucker M, Châtelain N, Laesser R, Crenner F, Handrich Y, Wilson R, Chevallier D. Combined use of two supervised learning algorithms to model sea turtle behaviours from tri-axial acceleration data. ACTA ACUST UNITED AC 2018; 221:jeb.177378. [PMID: 29661804 DOI: 10.1242/jeb.177378] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/08/2018] [Indexed: 11/20/2022]
Abstract
Accelerometers are becoming ever more important sensors in animal-attached technology, providing data that allow determination of body posture and movement and thereby helping to elucidate behaviour in animals that are difficult to observe. We sought to validate the identification of sea turtle behaviours from accelerometer signals by deploying tags on the carapace of a juvenile loggerhead (Caretta caretta), an adult hawksbill (Eretmochelys imbricata) and an adult green turtle (Chelonia mydas) at Aquarium La Rochelle, France. We recorded tri-axial acceleration at 50 Hz for each species for a full day while two fixed cameras recorded their behaviours. We identified behaviours from the acceleration data using two different supervised learning algorithms, Random Forest and Classification And Regression Tree (CART), treating the data from the adult animals as separate from the juvenile data. We achieved a global accuracy of 81.30% for the adult hawksbill and green turtle CART model and 71.63% for the juvenile loggerhead, identifying 10 and 12 different behaviours, respectively. Equivalent figures were 86.96% for the adult hawksbill and green turtle Random Forest model and 79.49% for the juvenile loggerhead, for the same behaviours. The use of Random Forest combined with CART algorithms allowed us to understand the decision rules implicated in behaviour discrimination, and thus remove or group together some 'confused' or under--represented behaviours in order to get the most accurate models. This study is the first to validate accelerometer data to identify turtle behaviours and the approach can now be tested on other captive sea turtle species.
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Affiliation(s)
- L Jeantet
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - F Dell'Amico
- Aquarium La Rochelle, quai Louis Prunier, 17000 La Rochelle, France
| | - M-A Forin-Wiart
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - M Coutant
- Aquarium La Rochelle, quai Louis Prunier, 17000 La Rochelle, France
| | - M Bonola
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - D Etienne
- Direction de l'Environnement, de l'Aménagement et du Logement Martinique, BP 7217, 97274 Schoelcher cedex, Martinique
| | - J Gresser
- Office de l'Eau Martinique, 7 avenue Condorcet, BP 32, 97201 Fort-de-France, Martinique
| | - S Regis
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - N Lecerf
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - F Lefebvre
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - B de Thoisy
- Institut Pasteur de la Guyane, 23 avenue Pasteur, BP 6010, Cayenne cedex, Guyane
| | - Y Le Maho
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - M Brucker
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - N Châtelain
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - R Laesser
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - F Crenner
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - Y Handrich
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
| | - R Wilson
- Biological Sciences, Institute of Environmental Sustainability, Swansea University, Swansea SA2 8PP, UK
| | - D Chevallier
- DEPE-IPHC, UMR 7178, CNRS, 23 rue Becquerel, 67087 Strasbourg cedex 2, France
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14
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Bang K, Kim J, Lee SI, Choi H. Hydrodynamic role of longitudinal dorsal ridges in a leatherback turtle swimming. Sci Rep 2016; 6:34283. [PMID: 27694826 PMCID: PMC5046118 DOI: 10.1038/srep34283] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/09/2016] [Indexed: 11/15/2022] Open
Abstract
Leatherback sea turtles (Dermochelys coriacea) are known to have a superior diving ability and be highly adapted to pelagic swimming. They have five longitudinal ridges on their carapace. Although it was conjectured that these ridges might be an adaptation for flow control, no rigorous study has been performed to understand their hydrodynamic roles. Here we show that these ridges are slightly misaligned to the streamlines around the body to generate streamwise vortices, and suppress or delay flow separation on the carapace, resulting in enhanced hydrodynamic performances during different modes of swimming. Our results suggest that shapes of some morphological features of living creatures, like the longitudinal ridges of the leatherback turtles, need not be streamlined for excellent hydro- or aerodynamic performances, contrary to our common physical intuition.
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Affiliation(s)
- Kyeongtae Bang
- Department of Mechanical & Aerospace Engineering, Seoul National University, Seoul, Korea
| | - Jooha Kim
- School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Sang-Im Lee
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, Korea
| | - Haecheon Choi
- Department of Mechanical & Aerospace Engineering, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
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15
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Hart KM, White CF, Iverson AR, Whitney N. Trading shallow safety for deep sleep: juvenile green turtles select deeper resting sites as they grow. ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00750] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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16
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Chen IH, Yang W, Meyers MA. Leatherback sea turtle shell: A tough and flexible biological design. Acta Biomater 2015; 28:2-12. [PMID: 26391496 DOI: 10.1016/j.actbio.2015.09.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/19/2015] [Accepted: 09/17/2015] [Indexed: 11/17/2022]
Abstract
The leatherback sea turtle is unique among chelonians for having a soft skin which covers its osteoderms. The osteoderm is composed of bony plates that are interconnected with collagen fibers in a structure called suture. The soft dermis and suture geometry enable a significant amount of flexing of the junction between adjacent osteoderms. This design allows the body to contract better than a hard-shelled sea turtle as it dives to depths of over 1,000 m. The leatherback turtle has ridges along the carapace to enhance the hydrodynamic flow and provide a tailored stiffness. The osteoderms are of two types: flat and ridged. The structure of the two types of osteoderms is characterized and their mechanical properties are investigated with particular attention to the failure mechanisms. They both are bony structures with a porous core sandwiched between compact layers that form the outside and inside surfaces. The compressive strength is highly anisotropic by virtue of the interaction between loading orientation and arrangement of porous and compact components of osteoderms. The angle of interpenetration at the suture of osteoderms is analyzed and compared with analytical predictions. The sutures have a triangular shape with an angle of ∼30° which provides a balance between the tensile strength of the osteoderms and shear strength of the collagen fiber layer and is verified by Li-Ortiz-Boyce in a previous study. This is confirmed by an FEM analysis. A calculation is developed to quantify the flexibility of the carapace and plastron as a function of the angular displacement at the sutures, predicting the interdependence between geometrical parameters and flexibility. STATEMENT OF SIGNIFICANCE The leatherback turtle is a magnificent chelonian whose decreasing numbers have brought it to the brink of extinction in the Pacific Ocean. This first study of the structure of its shell provides important new insights that explain its amazing capacity for diving: depths of over 1,000 m have been recorded. This is enabled by the flexibility between the bony plates comprising its shell, which is covered by a skin and not by hard keratin as all other turtles. We use the arsenal of Materials Science characterization techniques to probe the structure of the shell and explain its amazing structure and capacity for flexing, while retaining its protection capability.
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Affiliation(s)
- Irene H Chen
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wen Yang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Marc A Meyers
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA; Departments of Nanoengineering and Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
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17
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Chambault P, Pinaud D, Vantrepotte V, Kelle L, Entraygues M, Guinet C, Berzins R, Bilo K, Gaspar P, de Thoisy B, Le Maho Y, Chevallier D. Dispersal and Diving Adjustments of the Green Turtle Chelonia mydas in Response to Dynamic Environmental Conditions during Post-Nesting Migration. PLoS One 2015; 10:e0137340. [PMID: 26398528 PMCID: PMC4580322 DOI: 10.1371/journal.pone.0137340] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/14/2015] [Indexed: 11/18/2022] Open
Abstract
In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration.
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Affiliation(s)
- Philippine Chambault
- Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
- CNRS, UMR 7178, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
- * E-mail:
| | - David Pinaud
- Centre d’Études Biologiques de Chizé, UMR 7372 CNRS—Université de La Rochelle, 79360 Villiers-en-Bois, France
| | - Vincent Vantrepotte
- Laboratoire d’Océanologie et de Géosciences, UMR 8187 CNRS, 28 avenue Foch, BP 80 62930 Wimereux, France
- CNRS Guyane, USR 3456, av. Charlery, 97300 Cayenne, France
| | - Laurent Kelle
- WWF Guyane, N°5 Lotissement Katoury, F-97300 Cayenne, France
| | - Mathieu Entraygues
- Office National de la Chasse et de la Faune Sauvage—Cellule technique Guyane, Campus agronomique, BP 316, 97379 Kourou cedex, France
| | - Christophe Guinet
- Centre d’Études Biologiques de Chizé, UMR 7372 CNRS—Université de La Rochelle, 79360 Villiers-en-Bois, France
| | - Rachel Berzins
- Office National de la Chasse et de la Faune Sauvage—Cellule technique Guyane, Campus agronomique, BP 316, 97379 Kourou cedex, France
| | - Karin Bilo
- WWF Guianas, Henck Arronstraat 63, Paramaribo, Suriname
| | - Philippe Gaspar
- Collecte Localisation Satellites, Direction Océanographie Spatiale, 8–10 rue Hermès, 31520 Ramonville, France
| | - Benoît de Thoisy
- Association Kwata, 16 avenue Pasteur, BP 672, F-97335 Cayenne cedex, France
| | - Yvon Le Maho
- Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
- CNRS, UMR 7178, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
| | - Damien Chevallier
- Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
- CNRS, UMR 7178, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France
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18
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Graf PM, Wilson RP, Qasem L, Hackländer K, Rosell F. The Use of Acceleration to Code for Animal Behaviours; A Case Study in Free-Ranging Eurasian Beavers Castor fiber. PLoS One 2015; 10:e0136751. [PMID: 26317623 PMCID: PMC4552556 DOI: 10.1371/journal.pone.0136751] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 08/07/2015] [Indexed: 11/18/2022] Open
Abstract
Recent technological innovations have led to the development of miniature, accelerometer-containing electronic loggers which can be attached to free-living animals. Accelerometers provide information on both body posture and dynamism which can be used as descriptors to define behaviour. We deployed tri-axial accelerometer loggers on 12 free-ranging Eurasian beavers Castor fiber in the county of Telemark, Norway, and on four captive beavers (two Eurasian beavers and two North American beavers C. canadensis) to corroborate acceleration signals with observed behaviours. By using random forests for classifying behavioural patterns of beavers from accelerometry data, we were able to distinguish seven behaviours; standing, walking, swimming, feeding, grooming, diving and sleeping. We show how to apply the use of acceleration to determine behaviour, and emphasise the ease with which this non-invasive method can be implemented. Furthermore, we discuss the strengths and weaknesses of this, and the implementation of accelerometry on animals, illustrating limitations, suggestions and solutions. Ultimately, this approach may also serve as a template facilitating studies on other animals with similar locomotor modes and deliver new insights into hitherto unknown aspects of behavioural ecology.
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Affiliation(s)
- Patricia M. Graf
- Faculty of Arts and Sciences, Department of Environmental Sciences, Telemark University College, Bø i Telemark, Norway
- Department of Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
- * E-mail:
| | - Rory P. Wilson
- Swansea Moving Animal Research Team, Biosciences, College of Science, Swansea University, Singleton Park, Swansea, Wales, United Kingdom
| | - Lama Qasem
- Swansea Moving Animal Research Team, Biosciences, College of Science, Swansea University, Singleton Park, Swansea, Wales, United Kingdom
| | - Klaus Hackländer
- Department of Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Frank Rosell
- Faculty of Arts and Sciences, Department of Environmental Sciences, Telemark University College, Bø i Telemark, Norway
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Jouma'a J, Le Bras Y, Richard G, Vacquié‐Garcia J, Picard B, El Ksabi N, Guinet C. Adjustment of diving behaviour with prey encounters and body condition in a deep diving predator: the Southern Elephant Seal. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | - Yves Le Bras
- CEBC UMR 7372 ULR‐CNRS 79360 Villiers en Bois France
| | | | | | | | - Nory El Ksabi
- CEBC UMR 7372 ULR‐CNRS 79360 Villiers en Bois France
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20
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Martín López LM, Miller PJO, Aguilar de Soto N, Johnson M. Gait switches in deep-diving beaked whales: biomechanical strategies for long-duration dives. J Exp Biol 2015; 218:1325-38. [DOI: 10.1242/jeb.106013] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In addition to continuous stroking and stroke-and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorso-ventral acceleration, which we termed ‘type-B’ strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise ∼80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth.
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Affiliation(s)
| | - Patrick J. O. Miller
- SMRU (Sea Mammal Research Unit), University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Natacha Aguilar de Soto
- SMRU (Sea Mammal Research Unit), University of St Andrews, St Andrews, Fife KY16 8LB, UK
- BIOECOMAC (Biodiversidad, Ecología Marina y Conservación), University of La Laguna, La Laguna, 38206, Spain
| | - Mark Johnson
- SMRU (Sea Mammal Research Unit), University of St Andrews, St Andrews, Fife KY16 8LB, UK
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
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21
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Battaile BC, Sakamoto KQ, Nordstrom CA, Rosen DAS, Trites AW. Accelerometers identify new behaviors and show little difference in the activity budgets of lactating northern fur seals (Callorhinus ursinus) between breeding islands and foraging habitats in the eastern Bering Sea. PLoS One 2015; 10:e0118761. [PMID: 25807552 PMCID: PMC4373933 DOI: 10.1371/journal.pone.0118761] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/23/2015] [Indexed: 11/18/2022] Open
Abstract
We tagged 82 lactating northern fur seals (Callorhinus ursinus) with tri-axial accelerometers and magnetometers on two eastern Bering Sea islands (Bogoslof and St. Paul) with contrasting population trajectories. Using depth data, accelerometer data and spectral analysis we classified time spent diving (30%), resting (~7%), shaking and grooming their pelage (9%), swimming in the prone position (~10%) and two types of previously undocumented rolling behavior (29%), with the remaining time (~15%) unspecified. The reason for the extensive rolling behavior is not known. We ground-truthed the accelerometry signals for shaking and grooming and rolling behaviors—and identified the acceleration signal for porpoising—by filming tagged northern fur seals in captivity. Speeds from GPS interpolated data indicated that animals traveled fastest while in the prone position, suggesting that this behavior is indicative of destination-based swimming. Very little difference was found in the percentages of time spent in the categorical behaviors with respect to breeding islands (Bogoslof or St. Paul Island), forager type (cathemeral or nocturnal), and the region where the animals foraged (primarily on-shelf <200m, or off-shelf > 200m). The lack of significant differences between islands, regions and forager type may indicate that behaviors summarized over a trip are somewhat hardwired even though foraging trip length and when and where animals dive are known to vary with island, forager type and region.
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Affiliation(s)
- Brian C. Battaile
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Aquatic Ecosystems Research Laboratory, Vancouver, British Columbia, Canada
- * E-mail:
| | - Kentaro Q. Sakamoto
- Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060–0818, Japan
| | - Chad A. Nordstrom
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Aquatic Ecosystems Research Laboratory, Vancouver, British Columbia, Canada
| | - David A. S. Rosen
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Aquatic Ecosystems Research Laboratory, Vancouver, British Columbia, Canada
| | - Andrew W. Trites
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Aquatic Ecosystems Research Laboratory, Vancouver, British Columbia, Canada
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22
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García-Párraga D, Crespo-Picazo JL, de Quirós YB, Cervera V, Martí-Bonmati L, Díaz-Delgado J, Arbelo M, Moore MJ, Jepson PD, Fernández A. Decompression sickness ('the bends') in sea turtles. DISEASES OF AQUATIC ORGANISMS 2014; 111:191-205. [PMID: 25320032 DOI: 10.3354/dao02790] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Decompression sickness (DCS), as clinically diagnosed by reversal of symptoms with recompression, has never been reported in aquatic breath-hold diving vertebrates despite the occurrence of tissue gas tensions sufficient for bubble formation and injury in terrestrial animals. Similarly to diving mammals, sea turtles manage gas exchange and decompression through anatomical, physiological, and behavioral adaptations. In the former group, DCS-like lesions have been observed on necropsies following behavioral disturbance such as high-powered acoustic sources (e.g. active sonar) and in bycaught animals. In sea turtles, in spite of abundant literature on diving physiology and bycatch interference, this is the first report of DCS-like symptoms and lesions. We diagnosed a clinico-pathological condition consistent with DCS in 29 gas-embolized loggerhead sea turtles Caretta caretta from a sample of 67. Fifty-nine were recovered alive and 8 had recently died following bycatch in trawls and gillnets of local fisheries from the east coast of Spain. Gas embolization and distribution in vital organs were evaluated through conventional radiography, computed tomography, and ultrasound. Additionally, positive response following repressurization was clinically observed in 2 live affected turtles. Gas embolism was also observed postmortem in carcasses and tissues as described in cetaceans and human divers. Compositional gas analysis of intravascular bubbles was consistent with DCS. Definitive diagnosis of DCS in sea turtles opens a new era for research in sea turtle diving physiology, conservation, and bycatch impact mitigation, as well as for comparative studies in other air-breathing marine vertebrates and human divers.
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Affiliation(s)
- D García-Párraga
- Oceanografic, Veterinary Services, Parques Reunidos Valencia, Ciudad de las Artes y las Ciencias, C/ Eduardo Primo Yúfera 1B, 46013 Valencia, Spain
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23
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Scheyer TM, Danilov IG, Sukhanov VB, Syromyatnikova EV. The shell bone histology of fossil and extant marine turtles revisited. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12265] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Torsten M. Scheyer
- Paläontologisches Institut und Museum; Universität Zürich; Karl Schmid-Strasse 4 CH-8006 Zürich Switzerland
| | - Igor G. Danilov
- Zoological Institute of the Russian Academy of Sciences; Universitetskaya Emb., 1 St. Petersburg 199034 Russia
| | - Vladimir B. Sukhanov
- Paleontological Institute of the Russian Academy of Sciences; Profsoyuznaya Str. 123 Moscow 117997 Russia
| | - Elena V. Syromyatnikova
- Zoological Institute of the Russian Academy of Sciences; Universitetskaya Emb., 1 St. Petersburg 199034 Russia
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24
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Okuyama J, Kataoka K, Kobayashi M, Abe O, Yoseda K, Arai N. The regularity of dive performance in sea turtles: a new perspective from precise activity data. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.04.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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SADIKIN MOHAMAD, PUSPITANINGRUM RINI, WANANDI SEPTELIAINAWATI, SOEGIANTO RONDANGROEMIATI. Isolation and Characterization of Chelonia mydas Myoglobin. HAYATI JOURNAL OF BIOSCIENCES 2012. [DOI: 10.4308/hjb.19.2.60] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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26
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Fossette S, Schofield G, Lilley MKS, Gleiss AC, Hays GC. Acceleration data reveal the energy management strategy of a marine ectotherm during reproduction. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2011.01960.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Davenport J, Plot V, Georges JY, Doyle TK, James MC. Pleated turtle escapes the box--shape changes in Dermochelys coriacea. ACTA ACUST UNITED AC 2012; 214:3474-9. [PMID: 21957111 DOI: 10.1242/jeb.057182] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Typical chelonians have a rigid carapace and plastron that form a box-like structure that constrains several aspects of their physiology and ecology. The leatherback sea turtle, Dermochelys coriacea, has a flexible bony carapace strengthened by seven longitudinal ridges, whereas the plastron is reduced to an elliptical outer bony structure, so that the ventrum has no bony support. Measurements of the shell were made on adult female leatherbacks studied on the feeding grounds of waters off Nova Scotia (NS) and on breeding beaches of French Guiana (FG) to examine whether foraging and/or breeding turtles alter carapace size and/or shape. NS turtles exhibited greater mass and girth for a given curved carapace length (CCL) than FG turtles. Girth:CCL ratios rose during the feeding season, indicating increased girth. Measurements were made of the direct (straight) and surface (curved) distances between the medial longitudinal ridge and first right-hand longitudinal ridge (at 50% CCL). In NS turtles, the ratio of straight to curved inter-ridge distances was significantly higher than in FG turtles, indicating distension of the upper surfaces of the NS turtles between the ridges. FG females laid 11 clutches in the breeding season; although CCL and curved carapace width remained stable, girth declined between each nesting episode, indicating loss of mass. Straight to curved inter-ridge distance ratios did not change significantly during the breeding season, indicating loss of dorsal blubber before the onset of breeding. The results demonstrate substantial alterations in size and shape of female D. coriacea over periods of weeks to months in response to alterations in nutritional and reproductive status.
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Affiliation(s)
- John Davenport
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland.
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28
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Murphy C, Kelliher D, Davenport J. Shape and material characteristics of the trachea in the leatherback sea turtle promote progressive collapse and reinflation during dives. J Exp Biol 2012; 215:3064-71. [DOI: 10.1242/jeb.072108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
The leatherback turtle regularly undertakes deep dives and has been recorded attaining depths in excess of 1,200 m. Its trachea is an almost solid, elliptical-section tube of uncalcified hyaline cartilage with minimal connective tissue between successive rings. The structure appears to be advantageous for diving and perfectly designed for withstanding repeated collapse and reinflation. This study applies Boyle's law to the respiratory system (lungs, trachea and larynx) and estimates the changes in tracheal volume during a dive. These changes are subsequently compared with the results predicted by a corresponding finite element (FE) structural model, itself based on laboratory studies of the trachea of an adult turtle. Boyle's law predicts that the trachea will collapse progressively with greater volume change occurring in the early stages. The FE model reproduces the changes extremely well (agreeing closely with Boyle's law estimations) and provides visual representation of the deformed tracheal luminal area. Initially, the trachea compresses both ventrally and dorsally before levelling ventrally. Bulges are subsequently formed laterally and become more pronounced at deeper depths. The geometric configuration of the tracheal structure confers both homogeneity and strength upon it, which makes it extremely suited for enduring repeated collapse and re-expansion. The structure actually promotes collapse and is an adaptation to the turtle's natural environment in which large numbers of deep dives are performed annually.
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29
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Moore MJ, Hammar T, Arruda J, Cramer S, Dennison S, Montie E, Fahlman A. Hyperbaric computed tomographic measurement of lung compression in seals and dolphins. ACTA ACUST UNITED AC 2011; 214:2390-7. [PMID: 21697431 DOI: 10.1242/jeb.055020] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lung compression of vertebrates as they dive poses anatomical and physiological challenges. There has been little direct observation of this. A harbor and a gray seal, a common dolphin and a harbor porpoise were each imaged post mortem under pressure using a radiolucent, fiberglass, water-filled pressure vessel rated to a depth equivalent of 170 m. The vessel was scanned using computed tomography (CT), and supported by a rail and counterweighted carriage magnetically linked to the CT table movement. As pressure increased, total buoyancy of the animals decreased and lung tissue CT attenuation increased, consistent with compression of air within the lower respiratory tract. Three-dimensional reconstructions of the external surface of the porpoise chest showed a marked contraction of the chest wall. Estimation of the volumes of different body compartments in the head and chest showed static values for all compartments except the lung, which showed a pressure-related compression. The depth of estimated lung compression ranged from 58 m in the gray seal with lungs inflated to 50% total lung capacity (TLC) to 133 m in the harbor porpoise with lungs at 100% TLC. These observations provide evidence for the possible behavior of gas within the chest of a live, diving mammal. The estimated depths of full compression of the lungs exceeds previous indirect estimates of the depth at which gas exchange ceases, and concurs with pulmonary shunt measurements. If these results are representative for living animals, they might suggest a potential for decompression sickness in diving mammals.
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30
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Halsey LG, Jones TT, Jones DR, Liebsch N, Booth DT. Measuring energy expenditure in sub-adult and hatchling sea turtles via accelerometry. PLoS One 2011; 6:e22311. [PMID: 21829613 PMCID: PMC3150346 DOI: 10.1371/journal.pone.0022311] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 06/23/2011] [Indexed: 11/18/2022] Open
Abstract
Measuring the metabolic of sea turtles is fundamental to understanding their ecology yet the presently available methods are limited. Accelerometry is a relatively new technique for estimating metabolic rate that has shown promise with a number of species but its utility with air-breathing divers is not yet established. The present study undertakes laboratory experiments to investigate whether rate of oxygen uptake (VO2) at the surface in active sub-adult green turtles Chelonia mydas and hatchling loggerhead turtles Caretta caretta correlates with overall dynamic body acceleration (ODBA), a derivative of acceleration used as a proxy for metabolic rate. Six green turtles (25-44 kg) and two loggerhead turtles (20 g) were instrumented with tri-axial acceleration logging devices and placed singly into a respirometry chamber. The green turtles were able to submerge freely within a 1.5 m deep tank and the loggerhead turtles were tethered in water 16 cm deep so that they swam at the surface. A significant prediction equation for mean VO2 over an hour in a green turtle from measures of ODBA and mean flipper length (R(2) = 0.56) returned a mean estimate error across turtles of 8.0%. The range of temperatures used in the green turtle experiments (22-30 °C) had only a small effect on Vo₂. A VO2-ODBA equation for the loggerhead hatchling data was also significant (R(2) = 0.67). Together these data indicate the potential of the accelerometry technique for estimating energy expenditure in sea turtles, which may have important applications in sea turtle diving ecology, and also in conservation such as assessing turtle survival times when trapped underwater in fishing nets.
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Affiliation(s)
- Lewis G Halsey
- Department of Life Sciences, Roehampton University, London, United Kingdom.
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31
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Knight K. DIVING LEATHERBACKS REGULATE BUOYANCY. J Exp Biol 2010. [DOI: 10.1242/jeb.052928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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