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Gaudry MJ, Khudyakov J, Pirard L, Debier C, Crocker D, Crichton PG, Jastroch M. Terrestrial Birth and Body Size Tune UCP1 Functionality in Seals. Mol Biol Evol 2024; 41:msae075. [PMID: 38606905 PMCID: PMC11050727 DOI: 10.1093/molbev/msae075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/18/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
The molecular evolution of the mammalian heater protein UCP1 is a powerful biomarker to understand thermoregulatory strategies during species radiation into extreme climates, such as aquatic life with high thermal conductivity. While fully aquatic mammals lost UCP1, most semiaquatic seals display intact UCP1 genes, apart from large elephant seals. Here, we show that UCP1 thermogenic activity of the small-bodied harbor seal is equally potent compared to terrestrial orthologs, emphasizing its importance for neonatal survival on land. In contrast, elephant seal UCP1 does not display thermogenic activity, not even when translating a repaired or a recently highlighted truncated version. Thus, the thermogenic benefits for neonatal survival during terrestrial birth in semiaquatic pinnipeds maintained evolutionary selection pressure on UCP1 function and were only outweighed by extreme body sizes among elephant seals, fully eliminating UCP1-dependent thermogenesis.
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Affiliation(s)
- Michael J Gaudry
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Jane Khudyakov
- Department of Biological Sciences, University of the Pacific, Stockton, CA, USA
| | - Laura Pirard
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Cathy Debier
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Daniel Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Paul G Crichton
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich, UK
| | - Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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2
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Hoelzel AR, Gkafas GA, Kang H, Sarigol F, Le Boeuf B, Costa DP, Beltran RS, Reiter J, Robinson PW, McInerney N, Seim I, Sun S, Fan G, Li S. Genomics of post-bottleneck recovery in the northern elephant seal. Nat Ecol Evol 2024; 8:686-694. [PMID: 38383849 PMCID: PMC11009102 DOI: 10.1038/s41559-024-02337-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024]
Abstract
Populations and species are threatened by human pressure, but their fate is variable. Some depleted populations, such as that of the northern elephant seal (Mirounga angustirostris), recover rapidly even when the surviving population was small. The northern elephant seal was hunted extensively and taken by collectors between the early 1800s and 1892, suffering an extreme population bottleneck as a consequence. Recovery was rapid and now there are over 200,000 individuals. We sequenced 260 modern and 8 historical northern elephant seal nuclear genomes to assess the impact of the population bottleneck on individual northern elephant seals and to better understand their recovery. Here we show that inbreeding, an increase in the frequency of alleles compromised by lost function, and allele frequency distortion, reduced the fitness of breeding males and females, as well as the performance of adult females on foraging migrations. We provide a detailed investigation of the impact of a severe bottleneck on fitness at the genomic level and report on the role of specific gene systems.
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Affiliation(s)
| | - Georgios A Gkafas
- Department of Ichthyology and Aquatic Environment, University of Thessaly, Volos, Greece
| | - Hui Kang
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
- Innovation Research Center for Aquatic Mammals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | | | - Burney Le Boeuf
- Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Daniel P Costa
- Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Roxanne S Beltran
- Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Joanne Reiter
- Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Patrick W Robinson
- Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Nancy McInerney
- Center for Conservation Genomics, National Zoo and Conservation Biology Institute, Smithsonian Institution, Washington, DC, USA
| | - Inge Seim
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | | | | | - Songhai Li
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.
- Innovation Research Center for Aquatic Mammals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
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3
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Peterson SH, Peterson MG, Ackerman JT, Debier C, Goetsch C, Holser RR, Hückstädt LA, Johnson JC, Keates TR, McDonald BI, McHuron EA, Costa DP. Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups. Sci Rep 2024; 14:4693. [PMID: 38409311 PMCID: PMC10897339 DOI: 10.1038/s41598-024-54527-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/13/2024] [Indexed: 02/28/2024] Open
Abstract
Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200-1000 m depths). Maternal transfer of mercury to developing seal pups was related to maternal mercury contamination and was strongly correlated with maternal foraging behavior (biotelemetry and isotopes). Mercury concentrations in lanugo (hair grown in utero) were among the highest observed worldwide for young pinnipeds (geometric mean 23.01 μg/g dw, range 8.03-63.09 μg/g dw; n = 373); thus, some pups may be at an elevated risk of sub-lethal adverse health effects. Fetal mercury exposure was affected by maternal foraging geographic location and depth; mercury concentrations were highest in pups of the deepest diving, pelagic females. Moreover, pup lanugo mercury concentrations were strongly repeatable among successive pups of individual females, demonstrating relative consistency in pup mercury exposure based on maternal foraging strategies. Northern elephant seals are biosentinels of a remote deep-sea ecosystem. Our results suggest that mercury within North Pacific mesopelagic food webs may also pose an elevated risk to other mesopelagic-foraging predators and their offspring.
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Affiliation(s)
- Sarah H Peterson
- Western Ecological Research Center, Dixon Field Station, U.S. Geological Survey, 800 Business Park Drive Suite D, Dixon, CA, USA.
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA.
| | - Michael G Peterson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Joshua T Ackerman
- Western Ecological Research Center, Dixon Field Station, U.S. Geological Survey, 800 Business Park Drive Suite D, Dixon, CA, USA
| | - Cathy Debier
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Chandra Goetsch
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- CSS, Inc, Fairfax, VA, USA
| | - Rachel R Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Luis A Hückstädt
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Jennifer C Johnson
- Moss Landing Marine Labs, San Jose State University, Moss Landing, CA, USA
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Elizabeth A McHuron
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Daniel P Costa
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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Holser RR, Crocker DE, Favilla AR, Adachi T, Keates TR, Naito Y, Costa DP. Effects of disease on foraging behaviour and success in an individual free-ranging northern elephant seal. Conserv Physiol 2023; 11:coad034. [PMID: 37250476 PMCID: PMC10214463 DOI: 10.1093/conphys/coad034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 04/14/2023] [Accepted: 05/17/2023] [Indexed: 05/31/2023]
Abstract
Evaluating consequences of stressors on vital rates in marine mammals is of considerable interest to scientific and regulatory bodies. Many of these species face numerous anthropogenic and environmental disturbances. Despite its importance as a critical form of mortality, little is known about disease progression in air-breathing marine megafauna at sea. We examined the movement, diving, foraging behaviour and physiological state of an adult female northern elephant seal (Mirounga angustirostris) who suffered from an infection while at sea. Comparing her to healthy individuals, we identified abnormal behavioural patterns from high-resolution biologging instruments that are likely indicators of diseased and deteriorating condition. We observed continuous extended (3-30 minutes) surface intervals coinciding with almost no foraging attempts (jaw motion) during 2 weeks of acute illness early in her post-breeding foraging trip. Elephant seals typically spend ~ 2 minutes at the surface. There were less frequent but highly extended (30-200 minutes) surface periods across the remainder of the trip. Dive duration declined throughout the trip rather than increasing. This seal returned in the poorest body condition recorded for an adult female elephant seal (18.3% adipose tissue; post-breeding trip average is 30.4%). She was immunocompromised at the end of her foraging trip and has not been seen since that moulting season. The timing and severity of the illness, which began during the end of the energy-intensive lactation fast, forced this animal over a tipping point from which she could not recover. Additional physiological constraints to foraging, including thermoregulation and oxygen consumption, likely exacerbated her already poor condition. These findings improve our understanding of illness in free-ranging air-breathing marine megafauna, demonstrate the vulnerability of individuals at critical points in their life history, highlight the importance of considering individual health when interpreting biologging data and could help differentiate between malnutrition and other causes of at-sea mortality from transmitted data.
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Affiliation(s)
- Rachel R Holser
- Corresponding author: Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA. Tel.: +1 253-514-0110.
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, California, 94928, USA
| | - Arina R Favilla
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
| | - Taiki Adachi
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Daniel P Costa
- Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
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5
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Peterson SH, Ackerman JT, Holser RR, McDonald BI, Costa DP, Crocker DE. Mercury Bioaccumulation and Cortisol Interact to Influence Endocrine and Immune Biomarkers in a Free-Ranging Marine Mammal. Environ Sci Technol 2023; 57:5678-5692. [PMID: 36996077 DOI: 10.1021/acs.est.2c08974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Mercury bioaccumulation from deep-ocean prey and the extreme life history strategies of adult female northern elephant seals (Mirounga angustirostris) provide a unique system to assess the interactive effects of mercury and stress on animal health by quantifying blood biomarkers in relation to mercury (skeletal muscle and blood mercury) and cortisol concentrations. The thyroid hormone thyroxine (tT4) and the antibody immunoglobulin E (IgE) were associated with mercury and cortisol concentrations interactively, where the magnitude and direction of the association of each biomarker with mercury or cortisol changed depending on the concentration of the other factor. For example, when cortisol concentrations were lowest, tT4 was positively related to muscle mercury, whereas tT4 had a negative relationship with muscle mercury in seals that had the highest cortisol concentrations. Additionally, we observed that two thyroid hormones, triiodothyronine (tT3) and reverse triiodothyronine (rT3), were negatively (tT3) and positively (rT3) associated with mercury concentrations and cortisol in an additive manner. As an example, tT3 concentrations in late breeding seals at the median cortisol concentration decreased by 14% across the range of observed muscle mercury concentrations. We also observed that immunoglobulin M (IgM), the pro-inflammatory cytokine IL-6 (IL-6), and a reproductive hormone, estradiol, were negatively related to muscle mercury concentrations but were not related to cortisol. Specifically, estradiol concentrations in late molting seals decreased by 50% across the range of muscle mercury concentrations. These results indicate important physiological effects of mercury on free-ranging apex marine predators and interactions between mercury bioaccumulation and extrinsic stressors. Deleterious effects on animals' abilities to maintain homeostasis (thyroid hormones), fight off pathogens and disease (innate and adaptive immune system), and successfully reproduce (endocrine system) can have significant individual- and population-level consequences.
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Affiliation(s)
- Sarah H Peterson
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California 95620, United States of America
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California 95064, United States of America
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California 95064, United States of America
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, Dixon, California 95620, United States of America
| | - Rachel R Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California 95064, United States of America
| | - Birgitte I McDonald
- Moss Landing Marine Labs, San Jose State University, Moss Landing, California 95039, United States of America
| | - Daniel P Costa
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California 95064, United States of America
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California 95064, United States of America
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, California 94928, United States of America
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6
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Beltran RS, Hernandez KM, Condit R, Robinson PW, Crocker DE, Goetsch C, Kilpatrick AM, Costa DP. Physiological tipping points in the relationship between foraging success and lifetime fitness of a long-lived mammal. Ecol Lett 2023; 26:706-716. [PMID: 36888564 DOI: 10.1111/ele.14193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 03/09/2023]
Abstract
Although anthropogenic change is often gradual, the impacts on animal populations may be precipitous if physiological processes create tipping points between energy gain, reproduction or survival. We use 25 years of behavioural, diet and demographic data from elephant seals to characterise their relationships with lifetime fitness. Survival and reproduction increased with mass gain during long foraging trips preceding the pupping seasons, and there was a threshold where individuals that gained an additional 4.8% of their body mass (26 kg, from 206 to 232 kg) increased lifetime reproductive success three-fold (from 1.8 to 4.9 pups). This was due to a two-fold increase in pupping probability (30% to 76%) and a 7% increase in reproductive lifespan (6.0 to 6.4 years). The sharp threshold between mass gain and reproduction may explain reproductive failure observed in many species and demonstrates how small, gradual reductions in prey from anthropogenic disturbance could have profound implications for animal populations.
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Affiliation(s)
- Roxanne S Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - Keith M Hernandez
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA.,Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California, USA
| | - Richard Condit
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, California, USA
| | - Chandra Goetsch
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - A Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA.,Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California, USA
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7
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Cárdenas-Alayza S, Adkesson MJ, Edwards MR, Hirons AC, Gutiérrez D, Tremblay Y, Franco-Trecu V. Sympatric otariids increase trophic segregation in response to warming ocean conditions in Peruvian Humboldt Current System. PLoS One 2022; 17:e0272348. [PMID: 35951498 PMCID: PMC9371314 DOI: 10.1371/journal.pone.0272348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 07/18/2022] [Indexed: 11/26/2022] Open
Abstract
Determining trophic habits of predator communities is essential to measure interspecific interactions and response to environmental fluctuations. South American fur seals, Arctocephalus australis (SAFS) and sea lions Otaria byronia (SASL), coexist along the coasts of Peru. Recently, ocean warming events (2014–2017) that can decrease and impoverish prey biomass have occurred in the Peruvian Humboldt Current System. In this context, our aim was to assess the effect of warming events on long-term inter- and intra-specific niche segregation. We collected whisker from SAFS (55 females and 21 males) and SASL (14 females and 22 males) in Punta San Juan, Peru. We used δ13C and δ15N values serially archived in otariid whiskers to construct a monthly time series for 2005–2019. From the same period we used sea level anomaly records to determine shifts in the predominant oceanographic conditions using a change point analysis. Ellipse areas (SIBER) estimated niche width of species-sex groups and their overlap. We detected a shift in the environmental conditions marking two distinct periods (P1: January 2005—October 2013; P2: November 2013—December 2019). Reduction in δ15N in all groups during P2 suggests impoverished baseline values with bottom-up effects, a shift towards consuming lower trophic level prey, or both. Reduced overlap between all groups in P2 lends support of a more redundant assemblage during the colder P1 to a more trophically segregated assemblage during warmer P2. SASL females show the largest variation in response to the warming scenario (P2), reducing both ellipse area and δ15N mean values. Plasticity to adapt to changing environments and feeding on a more available food source without fishing pressure can be more advantageous for female SASL, albeit temporary trophic bottom-up effects. This helps explain larger population size of SASL in Peru, in contrast to the smaller and declining SAFS population.
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Affiliation(s)
- Susana Cárdenas-Alayza
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratorio de Ciencias del Mar, Universidad Peruana Cayetano Heredia, Lima, Peru
- UMR 248 MARBEC: IRD–Univ. Montpellier–CNRS–Ifremer, Sète cedex, France
- * E-mail:
| | - Michael J. Adkesson
- Chicago Zoological Society, Brookfield Zoo, Brookfield, Illinois, United States of America
| | - Mickie R. Edwards
- Halmos College of Arts and Sciences, Nova Southeastern University, Dania Beach, Florida, United States of America
| | - Amy C. Hirons
- Halmos College of Arts and Sciences, Nova Southeastern University, Dania Beach, Florida, United States of America
| | - Dimitri Gutiérrez
- Laboratorio de Ciencias del Mar, Universidad Peruana Cayetano Heredia, Lima, Peru
- Programa Maestría en Ciencias del Mar, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Yann Tremblay
- UMR 248 MARBEC: IRD–Univ. Montpellier–CNRS–Ifremer, Sète cedex, France
| | - Valentina Franco-Trecu
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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8
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Hounslow JL, Fossette S, Byrnes EE, Whiting SD, Lambourne RN, Armstrong NJ, Tucker AD, Richardson AR, Gleiss AC. Multivariate analysis of biologging data reveals the environmental determinants of diving behaviour in a marine reptile. R Soc Open Sci 2022; 9:211860. [PMID: 35958091 PMCID: PMC9364005 DOI: 10.1098/rsos.211860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 07/20/2022] [Indexed: 06/10/2023]
Abstract
Diving behaviour of 'surfacers' such as sea snakes, cetaceans and turtles is complex and multi-dimensional, thus may be better captured by multi-sensor biologging data. However, analysing these large multi-faceted datasets remains challenging, though a high priority. We used high-resolution multi-sensor biologging data to provide the first detailed description of the environmental influences on flatback turtle (Natator depressus) diving behaviour, during its foraging life-history stage. We developed an analytical method to investigate seasonal, diel and tidal effects on diving behaviour for 24 adult flatback turtles tagged with biologgers. We extracted 16 dive variables associated with three-dimensional and kinematic characteristics for 4128 dives. K-means and hierarchical cluster analyses failed to identify distinct dive types. Instead, principal component analysis objectively condensed the dive variables, removing collinearity and highlighting the main features of diving behaviour. Generalized additive mixed models of the main principal components identified significant seasonal, diel and tidal effects on flatback turtle diving behaviour. Flatback turtles altered their diving behaviour in response to extreme tidal and water temperature ranges, displaying thermoregulation and predator avoidance strategies while likely optimizing foraging in this challenging environment. This study demonstrates an alternative statistical technique for objectively interpreting diving behaviour from multivariate collinear data derived from biologgers.
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Affiliation(s)
- Jenna L. Hounslow
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
| | - Sabrina Fossette
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Evan E. Byrnes
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
- Faculty of Science, Simon Fraser University, British Columbia, Canada
| | - Scott D. Whiting
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Renae N. Lambourne
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
| | - Nicola J. Armstrong
- School of Electrical Engineering, Computing and Mathematical Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Anton D. Tucker
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Anthony R. Richardson
- Parks and Wildlife Service, West Kimberley District, Department of Biodiversity, Conservation and Attractions, Broome, Western Australia, Australia
| | - Adrian C. Gleiss
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
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9
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Franco‐Trecu V, Botta S, de Lima RC, Negrete J, Naya DE. Testing the niche variation hypothesis in pinnipeds. Mamm Rev 2022. [DOI: 10.1111/mam.12297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Valentina Franco‐Trecu
- Departamento de Ecología y Evolución, Facultad de Ciencias Universidad de la República Igua 4225 11400 Montevideo Uruguay
| | - Silvina Botta
- Laboratório de Ecologia e Conservação da Megafauna Marinha – EcoMega, Instituto de Oceanografia Universidade Federal do Rio Grande – FURG Avenida Italia km8 s/n Rio Grande RS 96203900 Brazil
| | - Renan C. de Lima
- Laboratório de Ecologia e Conservação da Megafauna Marinha – EcoMega, Instituto de Oceanografia Universidade Federal do Rio Grande – FURG Avenida Italia km8 s/n Rio Grande RS 96203900 Brazil
| | - Javier Negrete
- Departamento de Biología de Predadores Tope Instituto Antártico Argentino Av. 25 de Mayo 1143(B1650HMK) San Martin Buenos Aires Argentina
- Facultad de Ciencias Naturales Universidad Nacional de La Plata Av. 122 y 60 S/N (1900) La Plata Buenos Aires Argentina
| | - Daniel E. Naya
- Departamento de Ecología y Evolución, Facultad de Ciencias Universidad de la República Igua 4225 11400 Montevideo Uruguay
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10
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Kienle SS, Friedlaender AS, Crocker DE, Mehta RS, Costa DP. Trade-offs between foraging reward and mortality risk drive sex-specific foraging strategies in sexually dimorphic northern elephant seals. R Soc Open Sci 2022; 9:210522. [PMID: 35116140 PMCID: PMC8767210 DOI: 10.1098/rsos.210522] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 12/14/2021] [Indexed: 05/04/2023]
Abstract
Sex-specific phenotypic differences are widespread throughout the animal kingdom. Reproductive advantages provided by trait differences come at a cost. Here, we link sex-specific foraging strategies to trade-offs between foraging reward and mortality risk in sexually dimorphic northern elephant seals (Mirounga angustirostris). We analyse a decadal dataset on movement patterns, dive behaviour, foraging success and mortality rates. Females are deep-diving predators in open ocean habitats. Males are shallow-diving benthic predators in continental shelf habitats. Males gain six times more mass and acquire energy 4.1 times faster than females. High foraging success comes with a high mortality rate. Males are six times more likely to die than females. These foraging strategies and trade-offs are related to different energy demands and life-history strategies. Males use a foraging strategy with a high mortality risk to attain large body sizes necessary to compete for females, as only a fraction of the largest males ever mate. Females use a foraging strategy with a lower mortality risk, maximizing reproductive success by pupping annually over a long lifespan. Our results highlight how sex-specific traits can drive disparity in mortality rates and expand species' niche space. Further, trade-offs between foraging rewards and mortality risk can differentially affect each sex's ability to maximize fitness.
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Affiliation(s)
- Sarah S. Kienle
- Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
- Department of Biology, Baylor University, One Bear Place #97399, Waco, TX 76798, USA
| | - Ari S. Friedlaender
- Ocean Science, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Daniel E. Crocker
- Biology, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA 94928, USA
| | - Rita S. Mehta
- Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Daniel P. Costa
- Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
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11
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Piotrowski ER, Tift MS, Crocker DE, Pearson AB, Vázquez-Medina JP, Keith AD, Khudyakov JI. Ontogeny of Carbon Monoxide-Related Gene Expression in a Deep-Diving Marine Mammal. Front Physiol 2021; 12:762102. [PMID: 34744798 PMCID: PMC8567018 DOI: 10.3389/fphys.2021.762102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Marine mammals such as northern elephant seals (NES) routinely experience hypoxemia and ischemia-reperfusion events to many tissues during deep dives with no apparent adverse effects. Adaptations to diving include increased antioxidants and elevated oxygen storage capacity associated with high hemoprotein content in blood and muscle. The natural turnover of heme by heme oxygenase enzymes (encoded by HMOX1 and HMOX2) produces endogenous carbon monoxide (CO), which is present at high levels in NES blood and has been shown to have cytoprotective effects in laboratory systems exposed to hypoxia. To understand how pathways associated with endogenous CO production and signaling change across ontogeny in diving mammals, we measured muscle CO and baseline expression of 17 CO-related genes in skeletal muscle and whole blood of three age classes of NES. Muscle CO levels approached those of animals exposed to high exogenous CO, increased with age, and were significantly correlated with gene expression levels. Muscle expression of genes associated with CO production and antioxidant defenses (HMOX1, BVR, GPX3, PRDX1) increased with age and was highest in adult females, while that of genes associated with protection from lipid peroxidation (GPX4, PRDX6, PRDX1, SIRT1) was highest in adult males. In contrast, muscle expression of mitochondrial biogenesis regulators (PGC1A, ESRRA, ESRRG) was highest in pups, while genes associated with inflammation (HMOX2, NRF2, IL1B) did not vary with age or sex. Blood expression of genes involved in regulation of inflammation (IL1B, NRF2, BVR, IL10) was highest in pups, while HMOX1, HMOX2 and pro-inflammatory markers (TLR4, CCL4, PRDX1, TNFA) did not vary with age. We propose that ontogenetic upregulation of baseline HMOX1 expression in skeletal muscle of NES may, in part, underlie increases in CO levels and expression of genes encoding antioxidant enzymes. HMOX2, in turn, may play a role in regulating inflammation related to ischemia and reperfusion in muscle and circulating immune cells. Our data suggest putative ontogenetic mechanisms that may enable phocid pups to transition to a deep-diving lifestyle, including high baseline expression of genes associated with mitochondrial biogenesis and immune system activation during postnatal development and increased expression of genes associated with protection from lipid peroxidation in adulthood.
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Affiliation(s)
| | - Michael S. Tift
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Daniel E. Crocker
- Biology Department, Sonoma State University, Rohnert Park, CA, United States
| | - Anna B. Pearson
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States
| | - José P. Vázquez-Medina
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Anna D. Keith
- Department of Biological Sciences, University of the Pacific, Stockton, CA, United States
| | - Jane I. Khudyakov
- Department of Biological Sciences, University of the Pacific, Stockton, CA, United States
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12
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Halpin LR, Ross JD, Ramos R, Mott R, Carlile N, Golding N, Reyes‐González JM, Militão T, De Felipe F, Zajková Z, Cruz‐Flores M, Saldanha S, Morera‐Pujol V, Navarro‐Herrero L, Zango L, González‐Solís J, Clarke RH. Double‐tagging scores of seabirds reveals that light‐level geolocator accuracy is limited by species idiosyncrasies and equatorial solar profiles. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13698] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luke R. Halpin
- School of Biological Sciences Monash University Clayton VIC Australia
- Halpin Wildlife Research Vancouver BC Canada
| | - Jeremy D. Ross
- Oklahoma Biological Survey University of Oklahoma Norman OK USA
| | - Raül Ramos
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Rowan Mott
- School of Biological Sciences Monash University Clayton VIC Australia
| | - Nicholas Carlile
- Department of Planning, Industry and Environment Hurstville NSW Australia
| | - Nick Golding
- School of BioSciences University of Melbourne Parkville VIC Australia
| | - José Manuel Reyes‐González
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Teresa Militão
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Fernanda De Felipe
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Zuzana Zajková
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Marta Cruz‐Flores
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Sarah Saldanha
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Virginia Morera‐Pujol
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Leia Navarro‐Herrero
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Laura Zango
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Jacob González‐Solís
- Institut de Recerca de la Biodiversitat (IRBio) and Departament Biologia Evolutiva Ecologia i Ciències Ambientals, University of Barcelona Barcelona Spain
| | - Rohan H. Clarke
- School of Biological Sciences Monash University Clayton VIC Australia
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13
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Jones KA, Ratcliffe N, Votier SC, Lisovski S, Bonnet-Lebrun AS, Staniland IJ. Sexual segregation in juvenile Antarctic fur seals. Oecologia 2021. [PMID: 34309704 DOI: 10.1007/s00442-021-04983-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022]
Abstract
Sexual segregation, the differential space, habitat or resource use by males and females, can have profound implications for conservation, as one sex may be more vulnerable to environmental and anthropogenic stressors. The drivers of sexual segregation, such as sex differences in body size, breeding constraints, and social behaviour, have been well studied in adults but are poorly understood in immature animals. To determine whether sexual segregation occurs in juvenile Antarctic fur seals, Arctocephalus gazella, and investigate the underlying drivers, we deployed Global Location Sensors on 26 males and 19 females of 1-3 years of age at Bird Island, South Georgia. Sexual segregation occurred in foraging distribution, primarily in latitude, with females foraging closer to South Georgia and the Polar Front, and males foraging further south near the Antarctic Peninsula. This segregation was particularly evident in Feb-Apr and May-Nov, and males spent more time hauled out than females in May-Nov. Although juveniles have no immediate reproductive commitments, reproductive selection pressures are still likely to operate and drive sex differences in body size, risk-taking, and social roles. These factors, coupled with prey distribution, likely contributed to sexual segregation in juvenile Antarctic fur seals. Consequently, male and female juveniles may compete with different fisheries and respond differently to environmental change, highlighting the importance of considering sex and age groups in species conservation efforts.
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14
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Almeida N, Ramos JA, Rodrigues I, dos Santos I, Pereira JM, Matos DM, Araújo PM, Geraldes P, Melo T, Paiva VH. Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic. PLoS One 2021; 16:e0253095. [PMID: 34153067 PMCID: PMC8216530 DOI: 10.1371/journal.pone.0253095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/27/2021] [Indexed: 12/02/2022] Open
Abstract
In the oligotrophic tropical marine environment resources are usually more patchily distributed and less abundant to top predators. Thus, spatial and trophic competition can emerge, especially between related seabird species belonging to the same ecological guild. Here we studied the foraging ecology of two sympatric species-brown booby (BRBO) Sula leucogaster (breeding) and red-footed boobies (RFBO) Sula sula (non-breeding)-at Raso islet (Cabo Verde), across different seasons. Sexual segregation was only observed during Jun-Oct, when RFBO were present, with larger females BRBO remaining closer to the colonies, while males and RFBO travelled further and exploited different habitats. Overall, species appeared to prefer areas with specific oceanic features, particularly those related with oceanic currents and responsible for enhancing primary productivity in tropical oceanic areas (e.g. Sea Surface Height and Ocean Mixed Layer Thickness). Female BRBOs showed high foraging-site fidelity during the period of sympatry, while exploiting the same prey species as the other birds. However, during the months of co-existence (Jun.-Oct.), isotopic mixing models suggested that female BRBO would consume a higher proportion of epipelagic fish, whereas female RFBO would consume more squid compared to the other birds, possibly due to habitat-specific prey availability and breeding energy-constraints for BRBO. We conclude that divergent parental roles, environmental conditions, habitat preference and competition could be mechanisms simultaneously underlying sexual segregation for BRBO during a period of co-existence, while inter-specific foraging differences appear to be more affected by habitat preference and different breeding stages. These results support previous statements that BRBO can adapt their foraging ecology to different circumstances of environmental conditions and competition, and that marine physical features play an important role in foraging decisions of boobies.
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Affiliation(s)
- Nathalie Almeida
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
- Biosfera Cabo Verde, São Vicente, Cabo Verde
| | - Jaime A. Ramos
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
| | | | - Ivo dos Santos
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
| | - Jorge M. Pereira
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
| | - Diana M. Matos
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
| | - Pedro M. Araújo
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, Vairão, Portugal
| | - Pedro Geraldes
- SPEA–Sociedade Portuguesa para o Estudo das Aves, Lisboa, Portugal
| | - Tommy Melo
- Biosfera Cabo Verde, São Vicente, Cabo Verde
| | - Vitor H. Paiva
- Department of Life Sciences, University of Coimbra, MARE–Marine and Environmental Sciences Centre, Calçada Martim de Freitas, Coimbra, Portugal
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15
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Cerritelli G, Benhamou S, Luschi P. Evaluating vector navigation in green turtles migrating in a dynamic oceanic environment. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2021.1878281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Giulia Cerritelli
- Department of Biology, University of Pisa, Via A. Volta 6, Pisa 56126, Italy
| | - Simon Benhamou
- CNRS, Montpellier, and Cogitamus Lab, Centre d’Écologie Fonctionnelle et Evolutive, Montpellier, France
| | - Paolo Luschi
- Department of Biology, University of Pisa, Via A. Volta 6, Pisa 56126, Italy
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16
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Adachi T, Takahashi A, Costa DP, Robinson PW, Hückstädt LA, Peterson SH, Holser RR, Beltran RS, Keates TR, Naito Y. Forced into an ecological corner: Round-the-clock deep foraging on small prey by elephant seals. Sci Adv 2021; 7:7/20/eabg3628. [PMID: 33980496 PMCID: PMC8115928 DOI: 10.1126/sciadv.abg3628] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/22/2021] [Indexed: 06/01/2023]
Abstract
Small mesopelagic fishes dominate the world's total fish biomass, yet their ecological importance as prey for large marine animals is poorly understood. To reveal the little-known ecosystem dynamics, we identified prey, measured feeding events, and quantified the daily energy balance of 48 deep-diving elephant seals throughout their oceanic migrations by leveraging innovative technologies: animal-borne smart accelerometers and video cameras. Seals only attained positive energy balance after feeding 1000 to 2000 times per day on small fishes, which required continuous deep diving (80 to 100% of each day). Interspecies allometry suggests that female elephant seals have exceptional diving abilities relative to their body size, enabling them to exploit a unique foraging niche on small but abundant mesopelagic fish. This unique foraging niche requires extreme round-the-clock deep diving, limiting the behavioral plasticity of elephant seals to a changing mesopelagic ecosystem.
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Affiliation(s)
- Taiki Adachi
- National Institute of Polar Research, Tachikawa, Tokyo, Japan.
| | | | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Luis A Hückstädt
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Rachel R Holser
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Roxanne S Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
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17
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Vance HM, Hooker SK, Mikkelsen L, van Neer A, Teilmann J, Siebert U, Johnson M. Drivers and constraints on offshore foraging in harbour seals. Sci Rep 2021; 11:6514. [PMID: 33753752 DOI: 10.1038/s41598-021-85376-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/05/2021] [Indexed: 01/31/2023] Open
Abstract
Central place foragers are expected to offset travel costs between a central place and foraging areas by targeting productive feeding zones. Harbour seals (Phoca vitulina) make multi-day foraging trips away from coastal haul-out sites presumably to target rich food resources, but periodic track points from telemetry tags may be insufficient to infer reliably where, and how often, foraging takes place. To study foraging behaviour during offshore trips, and assess what factors limit trip duration, we equipped harbour seals in the German Wadden Sea with high-resolution multi-sensor bio-logging tags, recording 12 offshore trips from 8 seals. Using acceleration transients as a proxy for prey capture attempts, we found that foraging rates during travel to and from offshore sites were comparable to offshore rates. Offshore foraging trips may, therefore, reflect avoidance of intra-specific competition rather than presence of offshore foraging hotspots. Time spent resting increased by approx. 37 min/day during trips suggesting that a resting deficit rather than patch depletion may influence trip length. Foraging rates were only weakly correlated with surface movement patterns highlighting the value of integrating multi-sensor data from on-animal bio-logging tags (GPS, depth, accelerometers and magnetometers) to infer behaviour and habitat use.
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18
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Hindell MA, McMahon CR, Jonsen I, Harcourt R, Arce F, Guinet C. Inter- and intrasex habitat partitioning in the highly dimorphic southern elephant seal. Ecol Evol 2021; 11:1620-1633. [PMID: 33613994 PMCID: PMC7882946 DOI: 10.1002/ece3.7147] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/25/2020] [Accepted: 12/02/2020] [Indexed: 01/15/2023] Open
Abstract
Partitioning resources is a key mechanism for avoiding intraspecific competition and maximizing individual energy gain. However, in sexually dimorphic species it is difficult to discern if partitioning is due to competition or the different resource needs of morphologically distinct individuals. In the highly dimorphic southern elephant seal, there are intersexual differences in habitat use; at Iles Kerguelen, males predominantly use shelf waters, while females use deeper oceanic waters. There are equally marked intrasexual differences, with some males using the nearby Kerguelen Plateau, and others using the much more distant Antarctic continental shelf (~2,000 km away). We used this combination of inter and intrasexual behavior to test two hypotheses regarding habitat partitioning in highly dimorphic species. (a) that intersexual differences in habitat use will not appear until the seals diverge in body size and (b) that some habitats have higher rates of energy return than others. In particular, that the Antarctic shelf would provide higher energy returns than the Kerguelen Shelf, to offset the greater cost of travel. We quantified the habitat use of 187 southern elephant seals (102 adult females and 85 subadult males). The seals in the two groups were the same size (~2.4 m) removing the confounding effect of body size. We found that the intersexual differences in habitat use existed before the divergence in body size. Also, we found that the amount of energy gained was the same in all of the major habitats. This suggests that the use of shelf habitats by males is innate, and a trade-off between the need to access the large benthic prey available on shelf waters, against the higher risk of predation there. Intrasexual differences in habitat use are another trade-off; although there are fewer predators on the Antarctic shelf, it is subject to considerable interannual fluctuations in sea-ice extent. In contrast, the Kerguelen Plateau presents more consistent foraging opportunities, but contains higher levels of predation. Habitat partitioning in this highly dimorphic species is therefore the result of complex interplay of life history strategies, environmental conditions and predation pressure.
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Affiliation(s)
- Mark A. Hindell
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Clive R. McMahon
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
- IMOS Animal Tagging, Sydney Institute of Marine ScienceMosmanNew South WalesAustralia
- Department of Biological SciencesMacquarie UniversityNorth Ryde, SydneyNew South WalesAustralia
| | - Ian Jonsen
- Department of Biological SciencesMacquarie UniversityNorth Ryde, SydneyNew South WalesAustralia
| | - Robert Harcourt
- IMOS Animal Tagging, Sydney Institute of Marine ScienceMosmanNew South WalesAustralia
- Department of Biological SciencesMacquarie UniversityNorth Ryde, SydneyNew South WalesAustralia
| | - Fernando Arce
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Christophe Guinet
- Centre d’Etudes Biologiques de Chizé (CEBC)UMR 7372Université de la Rochelle‐CNRSVilliers en BoisFrance
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19
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Valenzuela-Toro AM, Zicos MH, Pyenson ND. Extreme dispersal or human-transport? The enigmatic case of an extralimital freshwater occurrence of a Southern elephant seal from Indiana. PeerJ 2020; 8:e9665. [PMID: 32953258 PMCID: PMC7474520 DOI: 10.7717/peerj.9665] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/15/2020] [Indexed: 11/20/2022] Open
Abstract
Elephant seals (Mirounga spp.) are the largest living pinnipeds, and the spatial scales of their ecology, with dives over 1 km in depth and foraging trips over 10,000 km long, are unrivalled by their near relatives. Here we report the discovery of an incomplete Holocene age Southern elephant seal (M. leonina) rostrum from Indiana, USA. The surviving material are two casts of the original specimen, which was collected in a construction excavation close to the Wabash River near Lafayette, Indiana. The original specimen was mostly destroyed for radiometric dating analyses in the 1970s, which resulted in an age of 1,260 ± 90 years before the present. The existence of sediments in the original specimen suggests some type of post depositional fluvial transportation. The prevalent evidence suggests that this male Southern elephant seal crossed the equator and the Gulf of Mexico, and then entered the Mississippi River system, stranding far upriver in Indiana or adjacent areas, similar to other reported examples of lost marine mammals in freshwater systems. Based on potential cut marks, we cannot exclude human-mediated transportation or scavenging by Indigenous peoples as a contributing factor of this occurrence. The material reported here represents by far the northernmost occurrence of a Southern elephant seal in the Northern Hemisphere ever recorded. The unusual occurrence of a top marine predator >1,000 km from the closest marine effluent as a potential extreme case of dispersal emphasizes how marine invasions of freshwater systems have happened frequently through historical (and likely geological) time.
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Affiliation(s)
- Ana M Valenzuela-Toro
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, United States of America.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
| | - Maria H Zicos
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.,Department of Earth Sciences, Natural History Museum, London, United Kingdom
| | - Nicholas D Pyenson
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA, United States of America
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20
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Stoffel MA, Acevedo-Whitehouse K, Morales-Durán N, Grosser S, Chakarov N, Krüger O, Nichols HJ, Elorriaga-Verplancken FR, Hoffman JI. Early sexual dimorphism in the developing gut microbiome of northern elephant seals. Mol Ecol 2020; 29:2109-2122. [PMID: 32060961 DOI: 10.1111/mec.15385] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
The gut microbiome is an integral part of a species' ecology, but we know little about how host characteristics impact its development in wild populations. Here, we explored the role of such intrinsic factors in shaping the gut microbiome of northern elephant seals (Mirounga angustirostris) during a critical developmental window of 6 weeks after weaning, when the pups stay ashore without feeding. We found substantial sex differences in the early-life gut microbiome, even though males and females could not yet be distinguished morphologically. Sex and age both explained around 15% of the variation in gut microbial beta diversity, while microbial communities sampled from the same individual showed high levels of similarity across time, explaining another 40% of the variation. Only a small proportion of the variation in beta diversity was explained by health status, assessed by full blood counts, but clinically healthy individuals had a greater microbial alpha diversity than their clinically abnormal peers. Across the post-weaning period, the northern elephant seal gut microbiome was highly dynamic. We found evidence for several colonization and extinction events as well as a decline in Bacteroides and an increase in Prevotella, a pattern that has previously been associated with the transition from nursing to solid food. Lastly, we show that genetic relatedness was correlated with gut microbiome similarity in males but not females, again reflecting early sex differences. Our study represents a naturally diet-controlled and longitudinal investigation of how intrinsic factors shape the early gut microbiome in a species with extreme sex differences in morphology and life history.
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Affiliation(s)
- Martin A Stoffel
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany.,School of Natural Sciences and Psychology, Faculty of Science, Liverpool John Moores University, Liverpool, UK.,Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Karina Acevedo-Whitehouse
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Queretaro, Queretaro, México.,The Marine Mammal Center, Sausalito, CA, USA
| | - Nami Morales-Durán
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Queretaro, Queretaro, México
| | - Stefanie Grosser
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Nayden Chakarov
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Oliver Krüger
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Hazel J Nichols
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany.,Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Fernando R Elorriaga-Verplancken
- Departamento de Pesquerías y Biología Marina, Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Instituto Politécnico Nacional, La Paz, Mexico
| | - Joseph I Hoffman
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany.,British Antarctic Survey, Cambridge, UK
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21
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Yoshino K, Takahashi A, Adachi T, Costa DP, Robinson PW, Peterson SH, Hückstädt LA, Holser RR, Naito Y. Acceleration-triggered animal-borne videos show a dominance of fish in the diet of female northern elephant seals. J Exp Biol 2020; 223:jeb212936. [PMID: 32041802 DOI: 10.1242/jeb.212936] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 01/31/2020] [Indexed: 01/04/2023]
Abstract
Knowledge of the diet of marine mammals is fundamental to understanding their role in marine ecosystems and response to environmental change. Recently, animal-borne video cameras have revealed the diet of marine mammals that make short foraging trips. However, novel approaches that allocate video time to target prey capture events is required to obtain diet information for species that make long foraging trips over great distances. We combined satellite telemetry and depth recorders with newly developed date-/time-, depth- and acceleration-triggered animal-borne video cameras to examine the diet of female northern elephant seals during their foraging migrations across the eastern North Pacific. We obtained 48.2 h of underwater video, from cameras mounted on the head (n=12) and jaw (n=3) of seals. Fish dominated the diet (78% of 697 prey items recorded) across all foraging locations (range: 37-55°N, 122-152°W), diving depths (range: 238-1167 m) and water temperatures (range: 3.2-7.4°C), while squid comprised only 7% of the diet. Identified prey included fish such as myctophids, Merluccius sp. and Icosteus aenigmaticus, and squid such as Histioteuthis sp., Octopoteuthis sp. and Taningia danae Our results corroborate fatty acid analysis, which also found that fish are more important in the diet, and are in contrast to stomach content analyses that found cephalopods to be the most important component of the diet. Our work shows that in situ video observation is a useful method for studying the at-sea diet of long-ranging marine predators.
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Affiliation(s)
- Kaori Yoshino
- Department of Polar Science, The Graduate University for Advanced Studies, SOKENDAI, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
| | - Akinori Takahashi
- Department of Polar Science, The Graduate University for Advanced Studies, SOKENDAI, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
| | - Taiki Adachi
- Department of Polar Science, The Graduate University for Advanced Studies, SOKENDAI, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
- School of Biology, University of St Andrews, Scottish Oceans Institute, East Sands, St Andrews, Fife KY16 9TS, UK
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Rachel R Holser
- Department of Ecology and Evolutionary Biology, Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
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22
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Juárez-Rodríguez M, Heckel G, Herguera-García JC, Elorriaga-Verplancken FR, Herzka SZ, Schramm Y. Trophic ecology of Mexican Pacific harbor seal colonies using carbon and nitrogen stable isotopes. PLoS One 2020; 15:e0225889. [PMID: 31967988 PMCID: PMC6975529 DOI: 10.1371/journal.pone.0225889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 11/14/2019] [Indexed: 11/28/2022] Open
Abstract
There is limited information that provides a comprehensive understanding of the trophic ecology of Mexican Pacific harbor seal (Phoca vitulina richardii) colonies. While scat analysis has been used to determine the diet of some colonies, the integrative characterization of its feeding habits on broader temporal and spatial scales remains limited. We examined potential feeding grounds, trophic niche width, and overlap, and inferred the degree of dietary specialization using stable carbon and nitrogen isotope ratios (δ13C and δ15N) in this subspecies. We analyzed δ13C and δ15N on fur samples from pups collected at five sites along the western coast of the Baja California Peninsula, Mexico. Fur of natal coat of Pacific harbor seal pups begins to grow during the seventh month in utero until the last stage of gestation. Therefore pup fur is a good proxy for the mother's feeding habits in winter (~December to March), based on the timing of gestation for the subspecies in this region. Our results indicated that the δ13C and δ15N values differed significantly among sampling sites, with the highest mean δ15N value occurring at the southernmost site, reflecting a well-characterized north to south latitudinal 15N-enrichment in the food web. The tendency identified in δ13C values, in which the northern colonies showed the most enriched values, suggests nearshore and benthic-demersal feeding habits. A low variance in δ13C and δ15N values for each colony (<1‰) and relatively small standard ellipse areas suggest a specialized foraging behavior in adult female Pacific harbor seals in Mexican waters.
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Affiliation(s)
- Maricela Juárez-Rodríguez
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Gisela Heckel
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Juan Carlos Herguera-García
- Departamento de Ecología Marina, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Fernando R. Elorriaga-Verplancken
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Departamento de Pesquerías y Biología Marina, La Paz, Baja California Sur, México
| | - Sharon Z. Herzka
- Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Yolanda Schramm
- Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, México
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Nowak BVR, Bowen WD, Whoriskey K, Lidgard DC, Mills Flemming JE, Iverson SJ. Foraging behaviour of a continental shelf marine predator, the grey seal ( Halichoerus grypus), is associated with in situ, subsurface oceanographic conditions. Mov Ecol 2020; 8:41. [PMID: 33093960 PMCID: PMC7574573 DOI: 10.1186/s40462-020-00225-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/30/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND The heterogeneous oceanographic conditions of continental shelf ecosystems result in a three-dimensionally patchy distribution of prey available to upper-trophic level predators. The association of bio-physical conditions with movement patterns of large marine predators has been demonstrated in diverse taxa. However, obtaining subsurface data that are spatio-temporally relevant to the decisions made by benthically-foraging species can be challenging. METHODS Between 2009 and 2015, grey seals were captured on Sable Island, Nova Scotia, Canada during summer and fall and instrumented with high-resolution archival GPS tags. These tags recorded location data as well as depth (m), temperature (°C), and light level measurements during dives, until animals returned to the haulout site to breed. Hidden Markov models were used to predict apparent foraging along movement tracks for 79 individuals (59 females, 20 males) every 3 h. In situ measurements were used to estimate chlorophyll-a concentration (mg m- 3) and temperature within the upper-water column (50 m) and temperature and depth at the bottom of dives. As chlorophyll-a could only be estimated from 10:00 to 14:00 AST for dive depths ≥50 m, we formulated two generalized linear mixed-effects models to test the association of predicted grey seal behavioural states with oceanographic conditions and phytoplankton biomass: the first representing conditions of the upper-water column likely to influence primary productivity, and a second model including environmental conditions encountered by grey seals at the bottom of dives, when seals were more likely to be foraging. RESULTS Predicted grey seal behavioural states were associated with fine-scale chlorophyll-a concentrations and other environmental conditions they encountered across the continental shelf. In the Water Column Model, season had no influence on the probability of observing apparent foraging, but chlorophyll-a, upper-water column temperature, and sex did, with females having a greater probability of foraging than males. In the Bottom Conditions Model, again season had no influence on the probability of apparent foraging, but females were over twice as likely as males to be foraging. CONCLUSIONS The results of this study highlight the value of in situ measurements of oceanographic properties that can be collected at high temporal resolution by animal-borne data loggers. These data provide insight into how inferred behavioural decisions made by large marine predators, such as the grey seal, may be influenced by fine-scale oceanographic conditions.
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Affiliation(s)
- B. V. R. Nowak
- Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
| | - W. D. Bowen
- Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
- Population Ecology Division, Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia B2Y 4A2 Canada
| | - K. Whoriskey
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
| | - D. C. Lidgard
- Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
- Population Ecology Division, Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia B2Y 4A2 Canada
| | - J. E. Mills Flemming
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
| | - S. J. Iverson
- Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4JI Canada
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24
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Sequeira AMM, Heupel MR, Lea MA, Eguíluz VM, Duarte CM, Meekan MG, Thums M, Calich HJ, Carmichael RH, Costa DP, Ferreira LC, Fernandéz-Gracia J, Harcourt R, Harrison AL, Jonsen I, McMahon CR, Sims DW, Wilson RP, Hays GC. The importance of sample size in marine megafauna tagging studies. Ecol Appl 2019; 29:e01947. [PMID: 31183944 DOI: 10.1002/eap.1947] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 04/10/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Telemetry is a key, widely used tool to understand marine megafauna distribution, habitat use, behavior, and physiology; however, a critical question remains: "How many animals should be tracked to acquire meaningful data sets?" This question has wide-ranging implications including considerations of statistical power, animal ethics, logistics, and cost. While power analyses can inform sample sizes needed for statistical significance, they require some initial data inputs that are often unavailable. To inform the planning of telemetry and biologging studies of marine megafauna where few or no data are available or where resources are limited, we reviewed the types of information that have been obtained in previously published studies using different sample sizes. We considered sample sizes from one to >100 individuals and synthesized empirical findings, detailing the information that can be gathered with increasing sample sizes. We complement this review with simulations, using real data, to show the impact of sample size when trying to address various research questions in movement ecology of marine megafauna. We also highlight the value of collaborative, synthetic studies to enhance sample sizes and broaden the range, scale, and scope of questions that can be answered.
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Affiliation(s)
- A M M Sequeira
- IOMRC and The University of Western Australia Oceans Institute, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - M R Heupel
- Australian Institute of Marine Science, PMB No 3, Townsville, Queensland, 4810, Australia
| | - M-A Lea
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Hobart, Tasmania, 7000, Australia
| | - V M Eguíluz
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (CSIC - UIB), E-07122, Palma de Mallorca, Spain
| | - C M Duarte
- Red Sea Research Centre (RSRC), King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - M G Meekan
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre (M096), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - M Thums
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre (M096), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - H J Calich
- IOMRC and The University of Western Australia Oceans Institute, Oceans Graduate School, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - R H Carmichael
- Dauphin Island Sea Lab and, University of South Alabama, 101 Bienville Boulevard, Dauphin Island, Alabama, 36528, USA
| | - D P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, 95060, USA
| | - L C Ferreira
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre (M096), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - J Fernandéz-Gracia
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (CSIC - UIB), E-07122, Palma de Mallorca, Spain
| | - R Harcourt
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - A-L Harrison
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, PO Box 37012 MRC 5503 MBC, Washington, D.C., 20013, USA
| | - I Jonsen
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - C R McMahon
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
- Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, 2088, New South Wales, Australia
| | - D W Sims
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, United Kingdom
- Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton, Southampton, SO14 3ZH, United Kingdom
| | - R P Wilson
- Department of Biosciences, Swansea University, Swansea, United Kingdom
| | - G C Hays
- Deakin University, Geelong, Victoria, Australia
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25
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Felis JJ, Adams J, Hodum PJ, Carle RD, Colodro V. Eastern Pacific migration strategies of pink-footed shearwaters Ardenna creatopus: implications for fisheries interactions and international conservation. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00969] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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26
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Smith GP, Bronstein JL, Papaj DR. Sex differences in pollinator behavior: Patterns across species and consequences for the mutualism. J Anim Ecol 2019; 88:971-985. [DOI: 10.1111/1365-2656.12988] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/11/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Gordon P. Smith
- Department of Ecology and Evolutionary BiologyUniversity of Arizona Tucson Arizona
| | - Judith L. Bronstein
- Department of Ecology and Evolutionary BiologyUniversity of Arizona Tucson Arizona
| | - Daniel R. Papaj
- Department of Ecology and Evolutionary BiologyUniversity of Arizona Tucson Arizona
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27
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Lemieux Lefebvre S, Lesage V, Michaud R, Humphries M. Classifying and combining herd surface activities and individual dive profiles to identify summer behaviours of beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies of the behaviour of diving animals usually focus on either individual dives or surface group activities, but these complementary observations are seldom combined in the same study. We here study the summer (June–October) behaviour of St. Lawrence Estuary belugas (Delphinapterus leucas (Pallas, 1776)) by combining fine-scale individual diving data from 27 time–depth–speed recorder deployments (conducted in 2002–2005) with surface activity data from 1413 focal herd follows (conducted in 1991–2012). We classified 6312 dives into seven dive types based on shape and swim speed. Dives were then combined into five bout types, including three pelagic, one benthic, and one near-surface. We classified surface activities of herds into six clusters, differentiated primarily by their associated movement patterns (milling or directional) and additionally by herd structure and dispersion and occurrence of acrobatic surface events. Finally, we used herd focal follows conducted while tracking an individual beluga to relate dive and bout types to surface activities. Results indicate that milling at the surface was more frequently related to benthic dives, potentially, associated with behaviours such as benthic foraging, resting, socializing, and care of young. Directional surface movements were more frequently associated with pelagic dives likely used during pelagic foraging, exploration, and travelling.
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Affiliation(s)
- S. Lemieux Lefebvre
- Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
| | - V. Lesage
- Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, QC G5H 3Z4, Canada
| | - R. Michaud
- Groupe de recherche et d’éducation sur les mammifères marins, Tadoussac, QC G0T 2A0, Canada
| | - M.M. Humphries
- Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
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Beltran RS, Ruscher-Hill B, Kirkham AL, Burns JM. An evaluation of three-dimensional photogrammetric and morphometric techniques for estimating volume and mass in Weddell seals Leptonychotes weddellii. PLoS One 2018; 13:e0189865. [PMID: 29320573 PMCID: PMC5761831 DOI: 10.1371/journal.pone.0189865] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 12/04/2017] [Indexed: 11/18/2022] Open
Abstract
Body mass dynamics of animals can indicate critical associations between extrinsic factors and population vital rates. Photogrammetry can be used to estimate mass of individuals in species whose life histories make it logistically difficult to obtain direct body mass measurements. Such studies typically use equations to relate volume estimates from photogrammetry to mass; however, most fail to identify the sources of error between the estimated and actual mass. Our objective was to identify the sources of error that prevent photogrammetric mass estimation from directly predicting actual mass, and develop a methodology to correct this issue. To do this, we obtained mass, body measurements, and scaled photos for 56 sedated Weddell seals (Leptonychotes weddellii). After creating a three-dimensional silhouette in the image processing program PhotoModeler Pro, we used horizontal scale bars to define the ground plane, then removed the below-ground portion of the animal's estimated silhouette. We then re-calculated body volume and applied an expected density to estimate animal mass. We compared the body mass estimates derived from this silhouette slice method with estimates derived from two other published methodologies: body mass calculated using photogrammetry coupled with a species-specific correction factor, and estimates using elliptical cones and measured tissue densities. The estimated mass values (mean ± standard deviation 345±71 kg for correction equation, 346±75 kg for silhouette slice, 343±76 kg for cones) were not statistically distinguishable from each other or from actual mass (346±73 kg) (ANOVA with Tukey HSD post-hoc, p>0.05 for all pairwise comparisons). We conclude that volume overestimates from photogrammetry are likely due to the inability of photo modeling software to properly render the ventral surface of the animal where it contacts the ground. Due to logistical differences between the "correction equation", "silhouette slicing", and "cones" approaches, researchers may find one technique more useful for certain study programs. In combination or exclusively, these three-dimensional mass estimation techniques have great utility in field studies with repeated measures sampling designs or where logistic constraints preclude weighing animals.
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Affiliation(s)
- Roxanne S. Beltran
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, United States of America
- * E-mail:
| | - Brandi Ruscher-Hill
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, United States of America
| | - Amy L. Kirkham
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America
| | - Jennifer M. Burns
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, United States of America
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29
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Abrahms B, Hazen EL, Bograd SJ, Brashares JS, Robinson PW, Scales KL, Crocker DE, Costa DP. Climate mediates the success of migration strategies in a marine predator. Ecol Lett 2017; 21:63-71. [PMID: 29096419 DOI: 10.1111/ele.12871] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/30/2017] [Accepted: 09/25/2017] [Indexed: 12/25/2022]
Abstract
Individual behavioural specialisation has far-reaching effects on fitness and population persistence. Theory predicts that unconditional site fidelity, that is fidelity to a site independent of past outcome, provides a fitness advantage in unpredictable environments. However, the benefits of alternative site fidelity strategies driving intraspecific variation remain poorly understood and have not been evaluated in different environmental contexts. We show that contrary to expectation, strong and weak site fidelity strategies in migratory northern elephant seals performed similarly over 10 years, but the success of each strategy varied interannually and was strongly mediated by climate conditions. Strong fidelity facilitated stable energetic rewards and low risk, while weak fidelity facilitated high rewards and high risk. Weak fidelity outperformed strong fidelity in anomalous climate conditions, suggesting that the evolutionary benefits of site fidelity may be upended by increasing environmental variability. We highlight how individual behavioural specialisation may modulate the adaptive capacity of species to climate change.
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Affiliation(s)
- Briana Abrahms
- NOAA Southwest Fisheries Science Center, Environmental Research Division, 99 Pacific St. #255A, Monterey, CA, 93940, USA.,Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
| | - Elliott L Hazen
- NOAA Southwest Fisheries Science Center, Environmental Research Division, 99 Pacific St. #255A, Monterey, CA, 93940, USA.,Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
| | - Steven J Bograd
- NOAA Southwest Fisheries Science Center, Environmental Research Division, 99 Pacific St. #255A, Monterey, CA, 93940, USA
| | - Justin S Brashares
- Department of Environmental Science, Policy, and Management, University of California Berkeley, 130 Mulford Hall #3114, Berkeley, CA, 94720, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
| | - Kylie L Scales
- University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Qld, Australia
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA, 94928, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
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30
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Naito Y, Costa DP, Adachi T, Robinson PW, Peterson SH, Mitani Y, Takahashi A. Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. Ecol Evol 2017; 7:6259-6270. [PMID: 28861230 PMCID: PMC5574793 DOI: 10.1002/ece3.3202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 05/27/2017] [Accepted: 05/30/2017] [Indexed: 11/23/2022] Open
Abstract
Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota‐poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. We also obtained video footage from seal‐mounted videos to understand their feeding in the OMZ. While the diel vertical migration pattern was apparent for most depths of the JME, some very deep dives, beyond the normal diel depth ranges, occurred episodically during daylight hours. The midmesopelagic zone was the main foraging zone for all seals. Larger seals tended to show smaller numbers of JME and lower feeding rates than smaller seals during migration, suggesting that larger seals tended to feed on larger prey to satisfy their metabolic needs. Larger seals also dived frequently to the deep OMZ, possibly because of a greater diving ability than smaller seals, suggesting their dependency on food in the deeper depth zones. Video observations showed that seals encountered the rarely reported ragfish (Icosteus aenigmaticus) in the depths of the OMZ, which failed to show an escape response from the seals, suggesting that low oxygen concentrations might reduce prey mobility. Less mobile prey in OMZ would enhance the efficiency of foraging in this zone, especially for large seals that can dive deeper and longer. We suggest that the OMZ plays an important role in structuring the mesopelagic ecosystem and for the survival and evolution of elephant seals.
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Affiliation(s)
- Yasuhiko Naito
- National Institute of Polar Research Midori-cho Tachikawa, Tokyo Japan
| | - Daniel P Costa
- Long Marine Laboratory Center for Ocean Health Institute of Marine Sciences University of California Santa Cruz CA USA
| | - Taiki Adachi
- National Institute of Polar Research Midori-cho Tachikawa, Tokyo Japan.,Present address: Department of Biological Sciences Graduate School of Science The University of Tokyo Tokyo 113-0032 Japan
| | - Patrick W Robinson
- Long Marine Laboratory Center for Ocean Health Institute of Marine Sciences University of California Santa Cruz CA USA
| | - Sarah H Peterson
- Long Marine Laboratory Center for Ocean Health Institute of Marine Sciences University of California Santa Cruz CA USA
| | - Yoko Mitani
- Field Science Center for Northern Biosphere Hokkaido University Bentencho Hakodate, Hokkaido Japan
| | - Akinori Takahashi
- National Institute of Polar Research Midori-cho Tachikawa, Tokyo Japan
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31
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Ferraro MS, Decker RR, Costa DP, Robinson PW, Houser DS, Crocker DE. Evaluating gain functions in foraging bouts using vertical excursions in northern elephant seals. Anim Behav 2017; 129:15-24. [DOI: 10.1016/j.anbehav.2017.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Crocker DE, Wenzel BK, Champagne CD, Houser DS. Adult male northern elephant seals maintain high rates of glucose production during extended breeding fasts. J Comp Physiol B 2017; 187:1183-1192. [DOI: 10.1007/s00360-017-1098-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/15/2017] [Accepted: 04/06/2017] [Indexed: 10/19/2022]
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Horimoto T, Mitani Y, Kobayashi M, Hattori K, Sakurai Y. Seasonal and Spatial Occurrence of Northern Fur Seals Callorhinus ursinus Around Northern Japan. Mammal Study 2017. [DOI: 10.3106/041.042.0106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Takanori Horimoto
- Wakkanai Fisheries Research Institute, Fisheries Research Department, Hokkaido Research Organization, 4-5-15 Suehiro, Wakkanai, Hokkaido 097-0001, Japan
| | - Yoko Mitani
- Laboratory of Marine Ecosystem Change Analysis, Field Science Center for Northern Biosphere, Hokkaido University, Hakodate Research Center for Fisheries and Oceans 20-5 Benten-cho, Hakodate, Hokkaido 040-0051, Japan
| | - Mari Kobayashi
- Department of Aqua Bioscience and Industry, Faculty of Bio-industry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido 099-2493, Japan
| | - Kaoru Hattori
- Hokkaido National Fisheries Research Institute, Japan Fisheries Research and Education Agency, Katsurakoi 116, Kushiro, Hokkaido 085-0802, Japan
| | - Yasunori Sakurai
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041-8611, Japan
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Peterson MG, Peterson SH, Debier C, Covaci A, Dirtu AC, Malarvannan G, Crocker DE, Costa DP. Serum POP concentrations are highly predictive of inner blubber concentrations at two extremes of body condition in northern elephant seals. Environ Pollut 2016; 218:651-663. [PMID: 27503056 DOI: 10.1016/j.envpol.2016.07.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 06/06/2023]
Abstract
Long-lived, upper trophic level marine mammals are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Internal tissues may accumulate and mobilize POP compounds at different rates related to the body condition of the animal and the chemical characteristics of individual POP compounds; however, collection of samples from multiple tissues is a major challenge to ecotoxicology studies of free-ranging marine mammals and the ability to predict POP concentrations in one tissue from another tissue remains rare. Northern elephant seals (Mirounga angustirostris) forage on mesopelagic fish and squid for months at a time in the northeastern Pacific Ocean, interspersed with two periods of fasting on land, which results in dramatic seasonal fluctuations in body condition. Using northern elephant seals, we examined commonly studied tissues in mammalian toxicology to describe relationships and determine predictive equations among tissues for a suite of POP compounds, including ΣDDTs, ΣPCBs, Σchlordanes, and ΣPBDEs. We collected paired blubber (inner and outer) and blood serum samples from adult female and male seals in 2012 and 2013 at Año Nuevo State Reserve (California, USA). For females (N = 24), we sampled the same seals before (late in molting fast) and after (early in breeding fast) their approximately seven month foraging trip. For males, we sampled different seals before (N = 14) and after (N = 15) their approximately four month foraging trip. We observed strong relationships among tissues for many, but not all compounds. Serum POP concentrations were strong predictors of inner blubber POP concentrations for both females and males, while serum was a more consistent predictor of outer blubber for males than females. The ability to estimate POP blubber concentrations from serum, or vice versa, has the potential to enhance toxicological assessment and physiological modeling. Furthermore, predictive equations may illuminate commonalities or distinctions in bioaccumulation across marine mammal species.
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Affiliation(s)
- Michael G Peterson
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA 94720-3114, USA.
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Cathy Debier
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 2/L7.05.08, 1348, Louvain-la-Neuve, Belgium
| | - Adrian Covaci
- Toxicological Center, Universiteit Antwerpen, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Alin C Dirtu
- Toxicological Center, Universiteit Antwerpen, Universiteitsplein 1, 2610, Wilrijk, Belgium; Department of Chemistry, "Al. I. Cuza" University of Iasi, Carol I Bvd, No. 11, 700506, Iasi, Romania
| | - Govindan Malarvannan
- Toxicological Center, Universiteit Antwerpen, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Peterson SH, Ackerman JT, Costa DP. Mercury correlations among blood, muscle, and hair of northern elephant seals during the breeding and molting fasts. Environ Toxicol Chem 2016; 35:2103-2110. [PMID: 26757244 DOI: 10.1002/etc.3365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/09/2015] [Accepted: 01/07/2016] [Indexed: 06/05/2023]
Abstract
Mercury (Hg) biomonitoring and toxicological risk assessments for marine mammals commonly sample different tissues, making comparisons with toxicity benchmarks and among species and regions difficult. Few studies have examined how life-history events, such as fasting, influence the relationship between total Hg (THg) concentrations in different tissues. The authors evaluated the relationships between THg concentrations in blood, muscle, and hair of female and male northern elephant seals (Mirounga angustirostris) at the start and end of the breeding and molting fasts. The relationships between tissues varied among tissue pairs and differed by sampling period and sex. Blood and muscle were generally related at all time periods; however, hair, an inert tissue, did not strongly represent the metabolically active tissues (blood and muscle) at all times of year. The strongest relationships between THg concentrations in hair and those in blood or muscle were observed during periods of active hair growth (end of the molting period) or during time periods when internal body conditions were similar to those when the hair was grown (end of the breeding fast). The results indicate that THg concentrations in blood or muscle can be translated to the other tissue type using the equations developed but that THg concentrations in hair were generally a poor index of internal THg concentrations except during the end of fasting periods. Environ Toxicol Chem 2016;35:2103-2110. © 2016 SETAC.
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Affiliation(s)
- Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, USA
| | - Joshua T Ackerman
- Dixon Field Station, Western Ecological Research Center, US Geological Survey, Dixon, California, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, USA
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Adachi T, Costa DP, Robinson PW, Peterson SH, Yamamichi M, Naito Y, Takahashi A. Searching for prey in a three‐dimensional environment: hierarchical movements enhance foraging success in northern elephant seals. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12686] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Taiki Adachi
- National Institute of Polar Research 10‐3 Midori‐cho Tachikawa Tokyo 190‐8518 Japan
- Department of Polar Science SOKENDAI (The Graduate University for Advanced Studies) 10‐3 Midori‐cho Tachikawa Tokyo 190‐8518 Japan
| | - Daniel P. Costa
- Department of Ecology and Evolutionary Biology University of California 100 Shaffer Road Santa Cruz CA 95060 USA
| | - Patrick W. Robinson
- Department of Ecology and Evolutionary Biology University of California 100 Shaffer Road Santa Cruz CA 95060 USA
| | - Sarah H. Peterson
- Department of Ecology and Evolutionary Biology University of California 100 Shaffer Road Santa Cruz CA 95060 USA
| | - Masato Yamamichi
- Hakubi Center for Advanced Research Kyoto University Yoshida‐honmachi Sakyo Kyoto 606‐8501 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga 520‐2113 Japan
| | - Yasuhiko Naito
- National Institute of Polar Research 10‐3 Midori‐cho Tachikawa Tokyo 190‐8518 Japan
| | - Akinori Takahashi
- National Institute of Polar Research 10‐3 Midori‐cho Tachikawa Tokyo 190‐8518 Japan
- Department of Polar Science SOKENDAI (The Graduate University for Advanced Studies) 10‐3 Midori‐cho Tachikawa Tokyo 190‐8518 Japan
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Hückstädt LA, Tift MS, Riet-Sapriza F, Franco-Trecu V, Baylis AMM, Orben RA, Arnould JPY, Sepulveda M, Santos-Carvallo M, Burns JM, Costa DP. Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lion (Otaria byronia). ACTA ACUST UNITED AC 2016; 219:2320-30. [PMID: 27247316 DOI: 10.1242/jeb.138677] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/17/2016] [Indexed: 11/20/2022]
Abstract
Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Because of their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral and physiological plasticity of a marine predator in different environments. We measured the oxygen stores and diving behavior of South American sea lions throughout most of its range, allowing us to demonstrate that diving ability and behavior vary across its range. We found no significant differences in mass-specific blood volumes of sea lions among field sites and a negative relationship between mass-specific oxygen storage and size, which suggests that exposure to different habitats and geographical locations better explains oxygen storage capacities and diving capability in South American sea lions than body size alone. The largest animals in our study (individuals from Uruguay) were the shallowest and shortest duration divers, and had the lowest mass-specific total body oxygen stores, while the deepest and longest duration divers (individuals from southern Chile) had significantly larger mass-specific oxygen stores, despite being much smaller animals. Our study suggests that the physiology of air-breathing diving predators is not fixed, but that it can be adjusted, to a certain extent, depending on the ecological setting and or habitat. These adjustments can be thought of as a 'training effect': as the animal continues to push its physiological capacity through greater hypoxic exposure, its breath-holding capacity increases.
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Affiliation(s)
- Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Laboratory, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Michael S Tift
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
| | - Federico Riet-Sapriza
- Laboratorio de Ecologia Molecular de Vertebrados Acuaticos (LEMVA), Departamento de Ciencias Biologicas, Facultad de Ciencias, Universidad de Los Andes, Carrera 1E, #18A-10, Bogota, Colombia
| | - Valentina Franco-Trecu
- Departamento de Ecología y Evolución Facultad de Ciencias, Universidad de la República, Iguá 4225 Esq. Mataojo C.P, 11400 Montevideo, Uruguay
| | - Alastair M M Baylis
- South Atlantic Environmental Research Institute, Stanley FIQQ1ZZ, Falkland Islands School of Life and Environmental Sciences, Deakin University, Warrnambool Campus, Geelong, Australia
| | - Rachael A Orben
- Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood Campus, Geelong, Australia
| | - Maritza Sepulveda
- Centro de Investigación y Gestión en Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
| | - Macarena Santos-Carvallo
- Centro de Investigación y Gestión en Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
| | - Jennifer M Burns
- Department of Biological Sciences, University of Alaska Anchorage. 3211 Providence Drive Anchorage, AK 99508, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Laboratory, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Abstract
One adaptation crucial to the survival of mammalian lineages that secondarily transitioned from land to water environments was the ability to capture and consume prey underwater. Phocid seals have evolved diverse feeding strategies to feed in the marine environment, and the objectives of this study were to document the specialized feeding morphologies and identify feeding strategies used by extant phocids. This study used principal component analysis (PCA) to determine the major axes of diversification in the skull for all extant phocid taxa and the recently extinct Caribbean monk seal (n = 19). Prey data gathered from the literature and musculoskeletal data from dissections were included to provide a comprehensive description of each feeding strategy. Random Forest analysis was used to determine the morphological, ecological and phylogenetic variables that best described each feeding strategy. There is morphological evidence for four feeding strategies in phocids: filter; grip and tear; suction; and pierce feeding. These feeding strategies are supported by quantitative cranial and mandibular characters, dietary information, musculoskeletal data and, for some species, behavioral observations. Most phocid species are pierce feeders, using a combination of biting and suction to opportunistically catch prey. Grip and tear and filter feeding are specialized strategies with specific morphological adaptations. These unique adaptations have allowed leopard seals (Hydrurga leptonyx) and crabeater seals (Lobodon carcinophaga) to exploit novel ecological niches and prey types. This study provides the first cranial and mandibular morphological evidence for the use of specialized suction feeding in hooded seals (Cystophora cristata), northern elephant seals (Mirounga angustirostris) and southern elephant seals (Mirounga leonina). The most important variables in determining the feeding strategy of a given phocid species were cranial and mandibular shape, diet, and phylogeny. These results provide a framework for understanding the evolution and adaptability of feeding strategies employed by extant phocid species, and these findings can be applied to other pinniped lineages and extinct taxa.
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Affiliation(s)
- Sarah S. Kienle
- Department of BiologySan Diego State UniversitySan DiegoCAUSA
- Department of Ecology and Evolutionary BiologyUniversity of California Santa CruzSanta CruzCAUSA
| | - Annalisa Berta
- Department of BiologySan Diego State UniversitySan DiegoCAUSA
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Drago M, Franco-Trecu V, Cardona L, Inchausti P, Tapia W, Páez-Rosas D. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki). PLoS One 2016; 11:e0147857. [PMID: 26808381 PMCID: PMC4725682 DOI: 10.1371/journal.pone.0147857] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/08/2016] [Indexed: 11/30/2022] Open
Abstract
Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ13C and δ15N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.
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Affiliation(s)
- Massimiliano Drago
- Programa PROMETEO-SENESCYT, Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, Quito, Ecuador
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
- * E-mail:
| | - Valentina Franco-Trecu
- Department of Ecology & Evolution, Faculty of Sciences, University of the Republic (UdeLaR), Montevideo, Uruguay
| | - Luis Cardona
- Department of Animal Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Pablo Inchausti
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
| | - Washington Tapia
- Department of Applied Research, Galapagos National Park Service, Puerto Ayora, Galápagos, Ecuador
- Galapagos Conservancy, Santa Cruz, Galápagos, Ecuador
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito (USFQ) and Galapagos Science Center, San Cristóbal, Galápagos, Ecuador
- Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Galápagos, Ecuador
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Fowler MA, Debier C, Champagne CD, Crocker DE, Costa DP. The demands of lactation promote differential regulation of lipid stores in fasting elephant seals. Gen Comp Endocrinol 2016; 225:125-132. [PMID: 26407500 DOI: 10.1016/j.ygcen.2015.09.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 09/03/2015] [Accepted: 09/22/2015] [Indexed: 12/25/2022]
Abstract
Fasting animals must ration stored reserves appropriately for metabolic demands. Animals that experience fasting concomitant with other metabolically demanding activities are presented with conflicting demands of energy conservation and expenditure. Our objective was to understand how fasting northern elephant seals regulate the mobilization of lipid reserves and subsequently milk lipid content during lactation. We sampled 36 females early and 39 at the end of lactation. To determine the separate influences of lactation from fasting, we also sampled fasting but non-lactating females early and late (8 and 6 seals, respectively) in their molting fasting period. Mass and adiposity were measured, as well as circulating non-esterified fatty acid (NEFA), triacylglycerol (TAG), cortisol, insulin and growth hormone levels. Milk was collected from lactating females. Milk lipid content increased from 31% in early to 51% in late lactation. In lactating females plasma NEFA was positively related to cortisol and negatively related to insulin, but in molting seals, only variation in cortisol was related to NEFA. Milk lipid content varied with mass, adiposity, NEFA, TAG, cortisol and insulin. Surprisingly, growth hormone concentration was not related to lipid metabolites or milk lipid. Suppression of insulin release appears to be the differential regulator of lipolysis in lactating versus molting seals, facilitating mobilization of stored lipids and maintenance of high NEFA concentrations for milk synthesis. Milk lipid was strongly impacted by the supply of substrate to the mammary gland, indicating regulation at the level of mobilization of lipid reserves.
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Affiliation(s)
- Melinda A Fowler
- Dept of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA.
| | - Cathy Debier
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Cory D Champagne
- Dept of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA
| | | | - Daniel P Costa
- Dept of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA
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Peterson SH, McHuron EA, Kennedy SN, Ackerman JT, Rea LD, Castellini JM, O'Hara TM, Costa DP. Evaluating Hair as a Predictor of Blood Mercury: The Influence of Ontogenetic Phase and Life History in Pinnipeds. Arch Environ Contam Toxicol 2016; 70:28-45. [PMID: 26149950 DOI: 10.1007/s00244-015-0174-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
Mercury (Hg) biomonitoring of pinnipeds increasingly utilizes nonlethally collected tissues such as hair and blood. The relationship between total Hg concentrations ([THg]) in these tissues is not well understood for marine mammals, but it can be important for interpretation of tissue concentrations with respect to ecotoxicology and biomonitoring. We examined [THg] in blood and hair in multiple age classes of four pinniped species. For each species, we used paired blood and hair samples to quantify the ability of [THg] in hair to predict [THg] in blood at the time of sampling and examined the influence of varying ontogenetic phases and life history of the sampled animals. Overall, we found that the relationship between [THg] in hair and blood was affected by factors including age class, weaning status, growth, and the time difference between hair growth and sample collection. Hair [THg] was moderately to strongly predictive of current blood [THg] for adult female Steller sea lions (Eumetopias jubatus), adult female California sea lions (Zalophus californianus), and adult harbor seals (Phoca vitulina), whereas hair [THg] was poorly predictive or not predictive (different times of year) of blood [THg] for adult northern elephant seals (Mirounga angustirostris). Within species, except for very young pups, hair [THg] was a weaker predictor of blood [THg] for prereproductive animals than for adults likely due to growth, variability in foraging behavior, and transitions between ontogenetic phases. Our results indicate that the relationship between hair [THg] and blood [THg] in pinnipeds is variable and that ontogenetic phase and life history should be considered when interpreting [THg] in these tissues.
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Affiliation(s)
- Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA.
| | - Elizabeth A McHuron
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA
| | - Stephanie N Kennedy
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Fairbanks, AK, 99701, USA
- Wildlife Toxicology Laboratory, Department of Veterinary Medicine, University of Alaska Fairbanks, P.O. Box 757750, Fairbanks, AK, 99775, USA
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA, 95620, USA
| | - Lorrie D Rea
- Institute of Northern Engineering, Water and Environmental Research Center, University of Alaska Fairbanks, P.O. Box 755910, Fairbanks, AK, 99775, USA
| | - J Margaret Castellini
- Wildlife Toxicology Laboratory, Department of Veterinary Medicine, University of Alaska Fairbanks, P.O. Box 757750, Fairbanks, AK, 99775, USA
| | - Todd M O'Hara
- Wildlife Toxicology Laboratory, Department of Veterinary Medicine, University of Alaska Fairbanks, P.O. Box 757750, Fairbanks, AK, 99775, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA
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Carter MID, Bennett KA, Embling CB, Hosegood PJ, Russell DJF. Navigating uncertain waters: a critical review of inferring foraging behaviour from location and dive data in pinnipeds. Mov Ecol 2016; 4:25. [PMID: 27800161 PMCID: PMC5080796 DOI: 10.1186/s40462-016-0090-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/17/2016] [Indexed: 05/09/2023]
Abstract
In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.
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Affiliation(s)
- Matt Ian Daniel Carter
- Marine Biology & Ecology Research Centre, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Kimberley A. Bennett
- School of Science, Engineering & Technology, Abertay University, DD1 1HG Dundee, UK
| | - Clare B. Embling
- Marine Biology & Ecology Research Centre, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Philip J. Hosegood
- Centre for Coast and Ocean Science & Engineering, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Debbie J. F. Russell
- Sea Mammal Research Unit, University of St. Andrews, KY16 8LB St. Andrews, UK
- Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, KY16 9LZ St. Andrews, UK
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Della Penna A, De Monte S, Kestenare E, Guinet C, d’Ovidio F. Quasi-planktonic behavior of foraging top marine predators. Sci Rep 2015; 5:18063. [PMID: 26666350 PMCID: PMC4678296 DOI: 10.1038/srep18063] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 11/09/2015] [Indexed: 11/09/2022] Open
Abstract
Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.
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Affiliation(s)
- Alice Della Penna
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7159, LOCEAN-IPSL CNRS/UPMC/IRD/MNHN, F-75005, Paris, France
- Univ Paris Diderot Cité, 5 Rue Thomas Mann, 75013 Paris, France
- CSIRO-UTAS Quantitative Marine Science Program, IMAS, Private Bag 129, Hobart, Tasmania 7001, Australia
| | - Silvia De Monte
- Ecole Normale Supérieure, Institut de Biologie de l’ENS (IBENS), UMR CNRS 8197 and INSERM U1024, 46 rue d’Ulm, F-75005 Paris, France
| | - Elodie Kestenare
- Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse III (OMP) and IRD, Toulouse, France
| | - Christophe Guinet
- Centre d’Etudes Biologiques de Chizé, 79360 Villiers-en-Bois, France
| | - Francesco d’Ovidio
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7159, LOCEAN-IPSL CNRS/UPMC/IRD/MNHN, F-75005, Paris, France
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Peterson SH, Peterson MG, Debier C, Covaci A, Dirtu AC, Malarvannan G, Crocker DE, Schwarz LK, Costa DP. Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants. Sci Total Environ 2015; 533:144-155. [PMID: 26151658 DOI: 10.1016/j.scitotenv.2015.06.097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/23/2015] [Accepted: 06/23/2015] [Indexed: 06/04/2023]
Abstract
As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N=24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N=14) and after (N=15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑DDTs and ∑PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑DDT and ∑PBDEs were highly correlated in blubber and serum. While ∑PCBs were highly correlated with ∑DDTs and ∑PBDEs in blubber and serum for males, ∑PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑DDTs, ∑PBDEs, MeO-BDE 47, as well as the ratio of ∑DDTs to ∑PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑DDTs and ∑PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in (13)C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep ocean food webs.
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Affiliation(s)
- Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA.
| | - Michael G Peterson
- Department of Environmental Science, Policy and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA 94720, USA
| | - Cathy Debier
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium
| | - Adrian Covaci
- Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Alin C Dirtu
- Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium; Department of Chemistry, "Al. I. Cuza" University of Iasi, 700506 Iasi, Romania
| | - Govindan Malarvannan
- Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928, USA
| | - Lisa K Schwarz
- Institute of Marine Sciences, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Beerman A, Ashe E, Preedy K, Williams R. Sexual segregation when foraging in an extremely social killer whale population. Behav Ecol Sociobiol 2016; 70:189-98. [DOI: 10.1007/s00265-015-2038-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Christin S, St-Laurent MH, Berteaux D. Evaluation of Argos Telemetry Accuracy in the High-Arctic and Implications for the Estimation of Home-Range Size. PLoS One 2015; 10:e0141999. [PMID: 26545245 PMCID: PMC4636246 DOI: 10.1371/journal.pone.0141999] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 10/15/2015] [Indexed: 11/18/2022] Open
Abstract
Animal tracking through Argos satellite telemetry has enormous potential to test hypotheses in animal behavior, evolutionary ecology, or conservation biology. Yet the applicability of this technique cannot be fully assessed because no clear picture exists as to the conditions influencing the accuracy of Argos locations. Latitude, type of environment, and transmitter movement are among the main candidate factors affecting accuracy. A posteriori data filtering can remove “bad” locations, but again testing is still needed to refine filters. First, we evaluate experimentally the accuracy of Argos locations in a polar terrestrial environment (Nunavut, Canada), with both static and mobile transmitters transported by humans and coupled to GPS transmitters. We report static errors among the lowest published. However, the 68th error percentiles of mobile transmitters were 1.7 to 3.8 times greater than those of static transmitters. Second, we test how different filtering methods influence the quality of Argos location datasets. Accuracy of location datasets was best improved when filtering in locations of the best classes (LC3 and 2), while the Douglas Argos filter and a homemade speed filter yielded similar performance while retaining more locations. All filters effectively reduced the 68th error percentiles. Finally, we assess how location error impacted, at six spatial scales, two common estimators of home-range size (a proxy of animal space use behavior synthetizing movements), the minimum convex polygon and the fixed kernel estimator. Location error led to a sometimes dramatic overestimation of home-range size, especially at very local scales. We conclude that Argos telemetry is appropriate to study medium-size terrestrial animals in polar environments, but recommend that location errors are always measured and evaluated against research hypotheses, and that data are always filtered before analysis. How movement speed of transmitters affects location error needs additional research.
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Affiliation(s)
- Sylvain Christin
- Chaire de recherche du Canada en biodiversité nordique and Center for Northern Studies, Université du Québec à Rimouski, Rimouski, Québec, Canada
| | - Martin-Hugues St-Laurent
- Département de Biologie, Chimie et Géographie, Center for Northern Studies and Centre for Forest Research, Université du Québec à Rimouski, Rimouski, Canada
| | - Dominique Berteaux
- Chaire de recherche du Canada en biodiversité nordique and Center for Northern Studies, Université du Québec à Rimouski, Rimouski, Québec, Canada
- * E-mail:
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Gordine SA, Fedak M, Boehme L. Fishing for drifts: detecting buoyancy changes of a top marine predator using a step-wise filtering method. J Exp Biol 2015; 218:3816-24. [PMID: 26486362 PMCID: PMC4712810 DOI: 10.1242/jeb.118109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 10/04/2015] [Indexed: 11/20/2022]
Abstract
In southern elephant seals (Mirounga leonina), fasting- and foraging-related fluctuations in body composition are reflected by buoyancy changes. Such buoyancy changes can be monitored by measuring changes in the rate at which a seal drifts passively through the water column, i.e. when all active swimming motion ceases. Here, we present an improved knowledge-based method for detecting buoyancy changes from compressed and abstracted dive profiles received through telemetry. By step-wise filtering of the dive data, the developed algorithm identifies fragments of dives that correspond to times when animals drift. In the dive records of 11 southern elephant seals from South Georgia, this filtering method identified 0.8-2.2% of all dives as drift dives, indicating large individual variation in drift diving behaviour. The obtained drift rate time series exhibit that, at the beginning of each migration, all individuals were strongly negatively buoyant. Over the following 75-150 days, the buoyancy of all individuals peaked close to or at neutral buoyancy, indicative of a seal's foraging success. Independent verification with visually inspected detailed high-resolution dive data confirmed that this method is capable of reliably detecting buoyancy changes in the dive records of drift diving species using abstracted data. This also affirms that abstracted dive profiles convey the geometric shape of drift dives in sufficient detail for them to be identified. Further, it suggests that, using this step-wise filtering method, buoyancy changes could be detected even in old datasets with compressed dive information, for which conventional drift dive classification previously failed.
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Affiliation(s)
- Samantha Alex Gordine
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Michael Fedak
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Lars Boehme
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife KY16 8LB, UK
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Maresh JL, Adachi T, Takahashi A, Naito Y, Crocker DE, Horning M, Williams TM, Costa DP. Summing the strokes: energy economy in northern elephant seals during large-scale foraging migrations. Mov Ecol 2015; 3:22. [PMID: 26380090 PMCID: PMC4570705 DOI: 10.1186/s40462-015-0049-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/26/2015] [Indexed: 06/01/2023]
Abstract
BACKGROUND The energy requirements of free-ranging marine mammals are challenging to measure due to cryptic and far-ranging feeding habits, but are important to quantify given the potential impacts of high-level predators on ecosystems. Given their large body size and carnivorous lifestyle, we would predict that northern elephant seals (Mirounga angustirostris) have elevated field metabolic rates (FMRs) that require high prey intake rates, especially during pregnancy. Disturbance associated with climate change or human activity is predicted to further elevate energy requirements due to an increase in locomotor costs required to accommodate a reduction in prey or time available to forage. In this study, we determined the FMRs, total energy requirements, and energy budgets of adult, female northern elephant seals. We also examined the impact of increased locomotor costs on foraging success in this species. RESULTS Body size, time spent at sea and reproductive status strongly influenced FMR. During the short foraging migration, FMR averaged 90.1 (SE = 1.7) kJ kg(-1)d(-1) - only 36 % greater than predicted basal metabolic rate. During the long migration, when seals were pregnant, FMRs averaged 69.4 (±3.0) kJ kg(-1)d(-1) - values approaching those predicted to be necessary to support basal metabolism in mammals of this size. Low FMRs in pregnant seals were driven by hypometabolism coupled with a positive feedback loop between improving body condition and reduced flipper stroking frequency. In contrast, three additional seals carrying large, non-streamlined instrumentation saw a four-fold increase in energy partitioned toward locomotion, resulting in elevated FMRs and only half the mass gain of normally-swimming study animals. CONCLUSIONS These results highlight the importance of keeping locomotion costs low for successful foraging in this species. In preparation for lactation and two fasting periods with high demands on energy reserves, migrating elephant seals utilize an economical foraging strategy whereby energy savings from reduced locomotion costs are shuttled towards somatic growth and fetal gestation. Remarkably, the energy requirements of this species, particularly during pregnancy, are 70-80 % lower than expected for mammalian carnivores, approaching or even falling below values predicted to be necessary to support basal metabolism in mammals of this size.
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Affiliation(s)
- JL Maresh
- />University of California Center for Ocean Health/Long Marine Lab, 100 Shaffer Rd., Santa Cruz, CA 95060 USA
| | - T. Adachi
- />Department of Polar Science, Graduate University for Advanced Studies, Midoricho Tachikawa, Japan
| | - A. Takahashi
- />Department of Polar Science, Graduate University for Advanced Studies, Midoricho Tachikawa, Japan
- />National Institute of Polar Research, Midoricho Tachikawa, Japan
| | - Y. Naito
- />National Institute of Polar Research, Midoricho Tachikawa, Japan
| | - DE Crocker
- />Department of Biology, Sonoma State University, Rohnert Park, USA
| | - M. Horning
- />Department of Fisheries & Wildlife, Marine Mammal Institute, Oregon State University, Newport, USA
| | - TM Williams
- />Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA
| | - DP Costa
- />Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA
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50
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Lewis S, Phillips RA, Burthe SJ, Wanless S, Daunt F. Contrasting responses of male and female foraging effort to year-round wind conditions. J Anim Ecol 2015; 84:1490-6. [PMID: 26283625 PMCID: PMC4989534 DOI: 10.1111/1365-2656.12419] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/26/2015] [Indexed: 11/27/2022]
Abstract
There is growing interest in the effects of wind on wild animals, given evidence that wind speeds are increasing and becoming more variable in some regions, particularly at temperate latitudes. Wind may alter movement patterns or foraging ability, with consequences for energy budgets and, ultimately, demographic rates. These effects are expected to vary among individuals due to intrinsic factors such as sex, age or feeding proficiency. Furthermore, this variation is predicted to become more marked as wind conditions deteriorate, which may have profound consequences for population dynamics as the climate changes. However, the interaction between wind and intrinsic effects has not been comprehensively tested. In many species, in particular those showing sexual size dimorphism, males and females vary in foraging performance. Here, we undertook year-round deployments of data loggers to test for interactions between sex and wind speed and direction on foraging effort in adult European shags Phalacrocorax aristotelis, a pursuit-diving seabird in which males are c. 18% heavier. We found that foraging time was lower at high wind speeds but higher during easterly (onshore) winds. Furthermore, there was an interaction between sex and wind conditions on foraging effort, such that females foraged for longer than males when winds were of greater strength (9% difference at high wind speeds vs. 1% at low wind speeds) and when winds were easterly compared with westerly (7% and 4% difference, respectively). The results supported our prediction that sex-specific differences in foraging effort would become more marked as wind conditions worsen. Since foraging time is linked to demographic rates in this species, our findings are likely to have important consequences for population dynamics by amplifying sex-specific differences in survival rates.
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Affiliation(s)
- Sue Lewis
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Richard A Phillips
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - Sarah J Burthe
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, EH26 0QB, UK
| | - Sarah Wanless
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, EH26 0QB, UK
| | - Francis Daunt
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, EH26 0QB, UK
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