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Charlanne LM, Chaise L, Sornette D, Piot E, McCafferty DJ, Ancel A, Gilbert C. Breaking the fast: first report of dives and ingestion events in molting southern elephant seals. Commun Biol 2024; 7:64. [PMID: 38191678 PMCID: PMC10774426 DOI: 10.1038/s42003-023-05720-2] [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: 04/12/2023] [Accepted: 12/18/2023] [Indexed: 01/10/2024] Open
Abstract
Southern elephant seals (SES) experience a 'catastrophic molt', a costly event characterized by the renewal of both hair and epidermis that requires high peripheral vascular circulation. Molting animals are therefore constrained by high metabolic heat loss and are thought to fast and remain on land. To examine the ability of individuals to balance the energetic constraints of molting on land we investigate the stomach temperature and movement patterns of molting female SES. We find that 79% of females swam and 61% ingested water or prey items, despite the cost of cold-water exposure while molting. This behavior was related to periods of warm and low wind conditions, and females that dived and ingested more often, lost less body mass. We conclude that the paradigm of fasting during the molt in this species, and the fitness consequences of this behavior should be reconsidered, especially in the context of a changing climate.
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Affiliation(s)
- Laura M Charlanne
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France.
| | - Laureline Chaise
- Hex·Data, 847 Route de Frans, 69400, Villefranche-sur-Saône, France
| | - Damien Sornette
- Hex·Data, 847 Route de Frans, 69400, Villefranche-sur-Saône, France
| | - Erwan Piot
- CNRS UMR5536, Université de Bordeaux, 33076, Bordeaux, France
- UMR 7179, CNRS/MNHN, Laboratoire MECADEV, 1 avenue du petit château, 91400, Brunoy, France
| | - Dominic J McCafferty
- Scottish Centre for Ecology and the Natural Environment, School of Biodiversity, One Health and Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - André Ancel
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Caroline Gilbert
- UMR 7179, CNRS/MNHN, Laboratoire MECADEV, 1 avenue du petit château, 91400, Brunoy, France
- Ecole Nationale Vétérinaire d'Alfort, 7 avenue du Général de Gaulle, 94704, Maisons-Alfort, France
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Giery ST, Layman CA. Ecological Consequences Of Sexually Selected Traits: An Eco-Evolutionary Perspective. QUARTERLY REVIEW OF BIOLOGY 2019. [DOI: 10.1086/702341] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Goedegebuure M, Melbourne-Thomas J, Corney SP, McMahon CR, Hindell MA. Modelling southern elephant seals Mirounga leonina using an individual-based model coupled with a dynamic energy budget. PLoS One 2018; 13:e0194950. [PMID: 29596456 PMCID: PMC5875804 DOI: 10.1371/journal.pone.0194950] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/13/2018] [Indexed: 01/08/2023] Open
Abstract
Higher trophic-level species are an integral component of any marine ecosystem. Despite their importance, methods for representing these species in end-to-end ecosystem models often have limited representation of life histories, energetics and behaviour. We built an individual-based model coupled with a dynamic energy budget for female southern elephant seals Mirounga leonina to demonstrate a method for detailed representation of marine mammals. We aimed to develop a model which could i) simulate energy use and life histories, as well as breeding traits of southern elephant seals in an emergent manner, ii) project a stable population over time, and iii) have realistic population dynamics and structure based on emergent life history features (such as age at first breeding, lifespan, fecundity and (yearling) survival). We evaluated the model's ability to represent a stable population over long time periods (>10 generations), including the sensitivity of the emergent properties to variations in key parameters. Analyses indicated that the model is sensitive to changes in resource availability and energy requirements for the transition from pup to juvenile, and juvenile to adult stage. This was particularly the case for breeding success and yearling survival. This model is suitable for use as a standalone tool for investigating the impacts of changes to behaviour and population responses of southern elephant seals.
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Affiliation(s)
- Merel Goedegebuure
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
| | - Jessica Melbourne-Thomas
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
- Australian Antarctic Division, Channel Highway, Kingston Tasmania 7050 Australia
| | - Stuart P. Corney
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
| | - Clive R. McMahon
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, New South Wales 2088, Australia
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
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Loza CM, Scarano AC, Galliari FC, Soibelzon LH, Negrete J, Carlini AA. The tympanic region of Otaria byronia (Otariidae, Carnivora) - morphology, ontogeny, age classes and dimorphism. J Anat 2018; 232:54-71. [PMID: 29082536 PMCID: PMC5735057 DOI: 10.1111/joa.12717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2017] [Indexed: 11/30/2022] Open
Abstract
Here we describe and explore for the first time the ontogeny and sexual dimorphism of the auditory region of Otaria byronia. We studied the tympanic region of skulls of 237 specimens of different ages and sexes. Geometric morphometric methods were used to analyze the tympanic bulla. In addition, 3D reconstructions of the tympanic bulla were performed using computed tomography analysis scans and a serial wearing technique. We provide a description of the external and internal morphology of the tympanic bulla in both sexes and across different stages (bioclasses). The average shape of the bulla in O. byronia has a subtriangular contour, with variations between sexes and ages. Each stage (bioclasses I, II, and III) is characterized by the respective mean shape of the tympanic bulla and designated as a morphoclass (1, 2, and 3). In all cases, the ectotympanic shows greater surface area than the endotympanic, as in other otariids, in contrast to Phocidae. During ontogeny, the relative size of the ectotympanic increases, growing in all directions and covering the endotympanic. This pattern is seen to the greatest extent in adult males, in which the ectotympanic forms an extremely well-developed apophysis jugulare. No differences in internal morphology of the tympanic cavity were recorded between ages and sexes. The bulla does not increase in thickness in successive age classes; in fact, the walls are extremely thin in the adult stages, despite the extensive development of its processes. This pattern is opposite that observed in Phocidae. In morphoclass 3, adult males older than 7 years undergo hypermorphic change that results in a peramorphic condition when compared to adult females. These changes probably follow the same pattern shown by the rest of the skull and contribute to the marked sexual dimorphism of the species.
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Affiliation(s)
- C. M. Loza
- División Paleontología de VertebradosMuseo de La PlataFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa PlataArgentina
| | - A. C. Scarano
- División Paleontología de VertebradosMuseo de La PlataFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa PlataArgentina
- Departamento de Ciencias AmbientalesUniversidad Nacional de AvellanedaBuenos AiresArgentina
- Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
| | - F. C. Galliari
- División Paleontología de VertebradosMuseo de La PlataFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa PlataArgentina
- Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
| | - L. H. Soibelzon
- División Paleontología de VertebradosMuseo de La PlataFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa PlataArgentina
- Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
| | - J. Negrete
- Departamento de Biología de Predadores TopeInstituto Antártico ArgentinoBuenos AiresArgentina
| | - A. A. Carlini
- División Paleontología de VertebradosMuseo de La PlataFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa PlataArgentina
- Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
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Corrigan LJ, Fabiani A, Chauke LF, McMahon CR, Bruyn M, Bester MN, Bastos A, Campagna C, Muelbert MMC, Hoelzel AR. Population differentiation in the context of Holocene climate change for a migratory marine species, the southern elephant seal. J Evol Biol 2016; 29:1667-79. [PMID: 27012933 DOI: 10.1111/jeb.12870] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/03/2016] [Accepted: 03/22/2016] [Indexed: 11/30/2022]
Affiliation(s)
- L. J. Corrigan
- School of Biological and Biomedical Sciences Durham University Durham UK
| | - A. Fabiani
- School of Biological and Biomedical Sciences Durham University Durham UK
- Dipartimento di Biologia Università degli Studi di Roma Tor Vergata Roma Italy
- Elephant Seal Research Group Sea Lion Island Falkland Islands
| | - L. F. Chauke
- School of Biological and Biomedical Sciences Durham University Durham UK
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - C. R. McMahon
- Sydney Institute of Marine Science Mosman NSW Australia
| | - M. Bruyn
- School of Biological and Biomedical Sciences Durham University Durham UK
| | - M. N. Bester
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - A. Bastos
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - C. Campagna
- Marine Program Wildlife Conservation Soc Buenos Aires Argentina
| | - M. M. C. Muelbert
- Instituto de Oceanografia Universidade Federal do Rio Grande Rio Grande Brasil
| | - A. R. Hoelzel
- School of Biological and Biomedical Sciences Durham University Durham UK
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Loza CM, Scarano AC, Soibelzon LH, Negrete J, Carlini AA. Morphology of the tympanic-basicranial region in Mirounga leonina (Phocidae, Carnivora), postnatal ontogeny and sexual dimorphism. J Anat 2015; 226:354-72. [PMID: 25827162 DOI: 10.1111/joa.12286] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2015] [Indexed: 11/28/2022] Open
Abstract
The auditory region of pinnipeds has seldom been described. Here we describe and analyze the ontogenetic trajectory of the tympanic bulla of the southern elephant seal, Mirounga leonina (Phocidae, Mammalia). This species is extremely sexually dimorphic and highly polygynous (organized in harems). We examined 118 specimens, arranged in three age classes (CI, CII, and CIII), ranging from newborn to adults (males and females). To analyze the overall size and shape of the tympanic bulla we performed a geometric morphometric analysis including 87 skulls. Females reach definitive shape and size of the bulla at earlier ontogenetic stages than males, in agreement with their earlier involvement in reproductive activities. The internal anatomy of the tympanic region (e.g. form and extension of the paries) does not show remarkable differences between sexes or age classes. The greatest differences between age classes are related to bone thickness, resulting from the apposition of new annual layers. An examination of possible sex-related external differences among age classes shows significant shape differences between males and females in CIII. The morphology observed in neonates is conserved across all individuals from CI, which included specimens up to 1 year old. Clear morphological differences were observed between CI individuals, on one hand, and CII individuals plus CIII females on the other. During cranial development of both male and females, the glenoid cavity expands and compresses the bulla; this condition reaches its maximum expression in CIII males. CIII males showed the greatest morphological differences, with respect to both CI and CII individuals, and CIII females.
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Affiliation(s)
- C M Loza
- División Paleontología de Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina
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Inferring spatial and temporal behavioral patterns of free-ranging manatees using saltwater sensors of telemetry tags. Mamm Biol 2015. [DOI: 10.1016/j.mambio.2014.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Leonardi MS, Aznar FJ, Crespo EA, Lazzari CR. Uncovering deep mysteries: the underwater life of an amphibious louse. JOURNAL OF INSECT PHYSIOLOGY 2014; 71:164-169. [PMID: 25449903 DOI: 10.1016/j.jinsphys.2014.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/30/2014] [Accepted: 10/31/2014] [Indexed: 06/04/2023]
Abstract
Despite the incredible success of insects in colonizing almost every habitat, they remain virtually absent in one major environment--the open sea. A variety of hypotheses have been raised to explain why just a few insect species are present in the ocean, but none of them appears to be fully explanatory. Lice belonging to the family Echinophthiriidae are ectoparasites on different species of pinnipeds and river otters, i.e. they have amphibious hosts, who regularly perform long excursions into the open sea reaching depths of hundreds of meters (thousands of feets). Consequently, lice must be able to support not only changes in their surrounding media, but also extreme variations in hydrostatic pressure as well as breathing in a low oxygen atmosphere. In order to shed some light on the way lice can survive during the diving excursions of their hosts, we have performed a series of experiments to test the survival capability of different instars of Antarctophthirus microchir (Phthiraptera: Anoplura) from South American sea lions Otaria flavescens, when submerged into seawater. These experiments were aimed at analyzing: (a) immersion tolerance along the louse life; (b) lice's ability to obtain oxygen from seawater; (c) physiological responses and mechanisms involved in survival underwater. Our experiments showed that the forms present in non-diving pups--i.e. eggs and first-instar nymphs--were unable to tolerate immersion in water, while following instars and adults, all usually found in diving hosts, supported it very well. Furthermore, as long as the level of oxygen dissolved in water was higher, the lice survival capability underwater increased, and the recovery period after returning to air declined. These results are discussed in relation to host ecology, host exploitation and lice functional morphology.
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Affiliation(s)
| | | | | | - Claudio R Lazzari
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261 - Université François Rabelais, Tours, France.
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de Bruyn P, Tosh C, Bester M, Cameron E, McIntyre T, Wilkinson I. Sex at sea: alternative mating system in an extremely polygynous mammal. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Eder EB, Lewis MN, Marín MR, Campagna C. On- and off-shelf diving effort of juvenile elephant seals from Península Valdés determined by light loggers. J Mammal 2011. [DOI: 10.1644/10-mamm-a-292.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Biuw M, Nøst OA, Stien A, Zhou Q, Lydersen C, Kovacs KM. Effects of hydrographic variability on the spatial, seasonal and diel diving patterns of southern elephant seals in the eastern Weddell Sea. PLoS One 2010; 5:e13816. [PMID: 21072199 PMCID: PMC2972216 DOI: 10.1371/journal.pone.0013816] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 10/01/2010] [Indexed: 11/23/2022] Open
Abstract
Weddell Sea hydrography and circulation is driven by influx of Circumpolar Deep Water (CDW) from the Antarctic Circumpolar Current (ACC) at its eastern margin. Entrainment and upwelling of this high-nutrient, oxygen-depleted water mass within the Weddell Gyre also supports the mesopelagic ecosystem within the gyre and the rich benthic community along the Antarctic shelf. We used Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) to examine the importance of hydrographic variability, ice cover and season on the movements and diving behavior of southern elephant seals in the eastern Weddell Sea region during their overwinter feeding trips from Bouvetøya. We developed a model describing diving depth as a function of local time of day to account for diel variation in diving behavior. Seals feeding in pelagic ice-free waters during the summer months displayed clear diel variation, with daytime dives reaching 500-1500 m and night-time targeting of the subsurface temperature and salinity maxima characteristic of CDW around 150–300 meters. This pattern was especially clear in the Weddell Cold and Warm Regimes within the gyre, occurred in the ACC, but was absent at the Dronning Maud Land shelf region where seals fed benthically. Diel variation was almost absent in pelagic feeding areas covered by winter sea ice, where seals targeted deep layers around 500–700 meters. Thus, elephant seals appear to switch between feeding strategies when moving between oceanic regimes or in response to seasonal environmental conditions. While they are on the shelf, they exploit the locally-rich benthic ecosystem, while diel patterns in pelagic waters in summer are probably a response to strong vertical migration patterns within the copepod-based pelagic food web. Behavioral flexibility that permits such switching between different feeding strategies may have important consequences regarding the potential for southern elephant seals to adapt to variability or systematic changes in their environment resulting from climate change.
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Affiliation(s)
- Martin Biuw
- Norwegian Polar Institute, Polar Environmental Centre, Tromsø, Norway.
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McMahon CR, Bester MN, Hindell MA, Brook BW, Bradshaw CJA. Shifting trends: detecting environmentally mediated regulation in long-lived marine vertebrates using time-series data. Oecologia 2008; 159:69-82. [PMID: 18987892 DOI: 10.1007/s00442-008-1205-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 10/07/2008] [Indexed: 11/30/2022]
Abstract
Assessing the status and trends in animal populations is essential for effective species conservation and management practices. However, unless time-series abundance data demonstrate rapid and reliable fluctuations, objective appraisal of directionality of trends is problematic. We adopted a multiple-working hypotheses approach based on information-theoretic and Bayesian multi-model inference to examine the population trends and form of intrinsic regulation demonstrated by a long-lived species, the southern elephant seal. We also determined the evidence for density dependence in 11 other well-studied marine mammal species. (1) We tested the type of population regulation for elephant seals from Marion Island (1986-2004) and from 11 other marine mammal species, and (2) we described the trends and behavior of the 19-year population time series at Marion Island to identify changes in population trends. We contrasted five plausible trend models using information-theoretic and Bayesian-inference estimates of model parsimony. Our analyses identified two distinct phases of population growth for this population with the inflexion occurring in 1998. Thus, the population decreased between 1986 and 1997 (-3.7% per annum) and increased between 1997 and 2004 (1.9% per annum). An index of environmental stochasticity, the Southern Oscillation Index, explained some of the variance in r and N. We determined analytically that there was good evidence for density dependence in the Marion Island population and that density dependence was widespread among marine mammal species (67% of species showed evidence for population regulation). This approach demonstrates the potential functionality of a relatively simple technique that can be applied to short time series to identify the type of regulation, and the uncertainty associated with the phenomenon, operating in populations of large mammals.
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Affiliation(s)
- Clive R McMahon
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, Gauteng, Republic of South Africa.
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MATTHIOPOULOS J, SMOUT S, WINSHIP AJ, THOMPSON D, BOYD IL, HARWOOD J. Getting beneath the surface of marine mammal – fisheries competition. Mamm Rev 2008. [DOI: 10.1111/j.1365-2907.2008.00123.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Biuw M, Boehme L, Guinet C, Hindell M, Costa D, Charrassin JB, Roquet F, Bailleul F, Meredith M, Thorpe S, Tremblay Y, McDonald B, Park YH, Rintoul SR, Bindoff N, Goebel M, Crocker D, Lovell P, Nicholson J, Monks F, Fedak MA. Variations in behavior and condition of a Southern Ocean top predator in relation to in situ oceanographic conditions. Proc Natl Acad Sci U S A 2007; 104:13705-10. [PMID: 17693555 PMCID: PMC1959446 DOI: 10.1073/pnas.0701121104] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Responses by marine top predators to environmental variability have previously been almost impossible to observe directly. By using animal-mounted instruments simultaneously recording movements, diving behavior, and in situ oceanographic properties, we studied the behavioral and physiological responses of southern elephant seals to spatial environmental variability throughout their circumpolar range. Improved body condition of seals in the Atlantic sector was associated with Circumpolar Deep Water upwelling regions within the Antarctic Circumpolar Current, whereas High-Salinity Shelf Waters or temperature/salinity gradients under winter pack ice were important in the Indian and Pacific sectors. Energetic consequences of these variations could help explain recently observed population trends, showing the usefulness of this approach in examining the sensitivity of top predators to global and regional-scale climate variability.
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Affiliation(s)
- M Biuw
- Natural Environment Research Council Sea Mammal Research Unit, Gatty Marine Laboratory, University of St. Andrews, St. Andrews, Fife KY16 8LB, United Kingdom.
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Galimberti F, Sanvito S, Braschi C, Boitani L. The cost of success: reproductive effort in male southern elephant seals (Mirounga leonina). Behav Ecol Sociobiol 2007. [DOI: 10.1007/s00265-007-0450-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lewis R, O'Connell TC, Lewis M, Campagna C, Hoelzel AR. Sex-specific foraging strategies and resource partitioning in the southern elephant seal (Mirounga leonina). Proc Biol Sci 2007; 273:2901-7. [PMID: 17015314 PMCID: PMC1664629 DOI: 10.1098/rspb.2006.3642] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of resource specializations is poorly understood, especially in marine systems. The southern elephant seal (Mirounga leonina) is the largest of the phocid seals, sexually dimorphic, and thought to prey predominantly on fish and squid. We collected vibrissae from male and female southern elephant seals, and assessed stable C and N isotope ratios along the length of the vibrissae. Given that whiskers grow slowly, this sampling strategy reflects any variation in feeding behaviour over a period of time. We found that isotopic variation among females was relatively small, and that the apparent prey choice and trophic level of females was different from that for males. Further, males showed a very broad range of trophic/prey choice positions, grouped into several clusters, and this included isotopic values too low to match a broad range of potential fish and cephalopod prey tested. One of these clusters overlapped with data for South American sea lions (Otaria flavescens), which were measured for comparison. Both male southern elephant seals and southern sea lions forage over the continental shelf, providing the potential for competition. We discuss the possibility that individual southern elephant seals are pursuing specialist foraging strategies to avoid competition, both with one another, and with the South American sea lions that breed nearby.
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Affiliation(s)
- Rebecca Lewis
- School of Biological and Biomedical Sciences, University of DurhamSouth Road, Durham DH1 3LE, UK
| | - Tamsin C O'Connell
- Research Laboratory for Archaeology and the History of Art, Oxford University6 Keble Road, Oxford OX1 3Q J, UK
- McDonald Institute for Archaeological Research, University of CambridgeDowning Street, Cambridge CB2 3ER, UK
| | - Mirtha Lewis
- Centro Nacional PatagonicoCONICET, Boulevard Brown s/n, 9120 Puerto Madryn, Chubut, Argentina
| | - Claudio Campagna
- Centro Nacional PatagonicoCONICET, Boulevard Brown s/n, 9120 Puerto Madryn, Chubut, Argentina
- Wildlife Conservation Society2300 Southern Boulevard Bronx, NY 10460, USA
| | - A. Rus Hoelzel
- School of Biological and Biomedical Sciences, University of DurhamSouth Road, Durham DH1 3LE, UK
- Author for correspondence ()
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Fabiani A, Galimberti F, Sanvito S, Hoelzel AR. Relatedness and site fidelity at the southern elephant seal, Mirounga leonina, breeding colony in the Falkland Islands. Anim Behav 2006. [DOI: 10.1016/j.anbehav.2005.11.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Adult female survival, population trend, and the implications of early primiparity in a capital breeder, the southern elephant seal (Mirounga leonina). J Zool (1987) 2004. [DOI: 10.1017/s0952836904004984] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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McConnell B, Fedak M, Burton HR, Engelhard GH, Reijnders PJH. Movements and foraging areas of naive, recently weaned southern elephant seal pups. J Anim Ecol 2002. [DOI: 10.1046/j.0021-8790.2001.00576.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Croll DA, Acevedo-Gutiérrez A, Tershy BR, Urbán-Ramírez J. The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores? Comp Biochem Physiol A Mol Integr Physiol 2001; 129:797-809. [PMID: 11440866 DOI: 10.1016/s1095-6433(01)00348-8] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many diving seabirds and marine mammals have been found to regularly exceed their theoretical aerobic dive limit (TADL). No animals have been found to dive for durations that are consistently shorter than their TADL. We attached time-depth recorders to 7 blue whales and 15 fin whales (family Balaenopteridae). The diving behavior of both species was similar, and we distinguished between foraging and traveling dives. Foraging dives in both species were deeper, longer in duration and distinguished by a series of vertical excursions where lunge feeding presumably occurred. Foraging blue whales lunged 2.4 (+/-1.13) times per dive, with a maximum of six times and average vertical excursion of 30.2 (+/-10.04) m. Foraging fin whales lunged 1.7 (+/-0.88) times per dive, with a maximum of eight times and average vertical excursion of 21.2 (+/-4.35) m. The maximum rate of ascent of lunges was higher than the maximum rate of descent in both species, indicating that feeding lunges occurred on ascent. Foraging dives were deeper and longer than non-feeding dives in both species. On average, blue whales dived to 140.0 (+/-46.01) m and 7.8 (+/-1.89) min when foraging, and 67.6 (+/-51.46) m and 4.9 (+/-2.53) min when not foraging. Fin whales dived to 97.9 (+/-32.59) m and 6.3 (+/-1.53) min when foraging and to 59.3 (+/-29.67) m and 4.2 (+/-1.67) min when not foraging. The longest dives recorded for both species, 14.7 min for blue whales and 16.9 min for fin whales, were considerably shorter than the TADL of 31.2 and 28.6 min, respectively. An allometric comparison of seven families diving to an average depth of 80-150 m showed a significant relationship between body mass and dive duration once Balaenopteridae whales, with a mean dive duration of 6.8 min, were excluded from the analysis. Thus, the short dive durations of blue whales and fin whales cannot be explained by the shallow distribution of their prey. We propose instead that short duration diving in large whales results from either: (1) dispersal behavior of prey; or (2) a high energetic cost of foraging.
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Affiliation(s)
- D A Croll
- Institute of Marine Sciences, A316 Earth and Marine Sciences Bldg., University of California, Santa Cruz, CA 95064, USA.
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Hoelzel AR, Campagna C, Arnbom T. Genetic and morphometric differentiation between island and mainland southern elephant seal populations. Proc Biol Sci 2001; 268:325-32. [PMID: 11217905 PMCID: PMC1088610 DOI: 10.1098/rspb.2000.1375] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We compare genetic (both nuclear and mitochondrial) and morphometric measures between two putative populations of southern elephant seal (Mirounga leonina), and interpret the results in the context of data from mark-recapture and satellite-telemetric studies. One population is on the Argentine mainland, while the other is 2,400 km away on South Georgia island. We found pronounced differentiation at the mitochondrial DNA (mtDNA) control region that was distinct from the pattern of variation seen among island rookeries. Some morphometric characters and seven out of ten nuclear-DNA markers also showed differentiation between the island and mainland sites. Diversity at nuclear markers was high in both populations but mtDNA diversity was low in the mainland population, suggesting a founder event and little subsequent immigration of females. Morphological differences may suggest different selective environments at the two sites.
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Affiliation(s)
- A R Hoelzel
- Department of Biological Sciences, Durham University, UK.
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