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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Individual Quality Drives Life History Variation in a Long-Lived Marine Predator. Am Nat 2023; 202:351-367. [PMID: 37606942 DOI: 10.1086/725451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
AbstractIndividual quality and environmental conditions may mask or interact with energetic trade-offs in life history evolution. Deconstructing these sources of variation is especially difficult in long-lived species that are rarely observed on timescales long enough to disentangle these effects. Here, we investigated relative support for variation in female quality and costs of reproduction as factors shaping differences in life history trajectories using a 32-year dataset of repeated reproductive measurements from 273 marked, known-age female gray seals (Halichoerus grypus). We defined individual reproductive investment using two traits, reproductive frequency (a female's probability of breeding) and provisioning performance (offspring weaning mass). Fitted hierarchical Bayesian models identified individual investment relative to conspecifics (over a female's entire life and in three age classes) and subsequently estimated how these investment metrics and the Atlantic Multidecadal Oscillation are associated with longevity. Individual differences (i.e., quality) contributed a large portion of the variance in reproductive traits. Females that consistently invest well in their offspring relative to other females survive longer. The best-supported model estimated survival as a function of age class-specific provisioning performance, where late-life performance was particularly variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. Overall, these results suggest that in gray seals, individual quality is a stronger driver in life history variation than individual strategies resulting from energetic trade-offs.
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2
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Vermeulen E, Thavar T, Glarou M, Ganswindt A, Christiansen F. Decadal decline in maternal body condition of a Southern Ocean capital breeder. Sci Rep 2023; 13:3228. [PMID: 36828886 PMCID: PMC9958138 DOI: 10.1038/s41598-023-30238-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 02/20/2023] [Indexed: 02/26/2023] Open
Abstract
The changing physical properties of the Southern Ocean are known to impact the recruitment and survival of Antarctic krill (Euphausia superba). For oceanic krill predators, the resulting reduced energy intake may lead to population-level effects likely preceded by an alteration in the animals' body condition. This is especially true for capital breeders that rely on stored energy for successful reproduction. One such Southern Ocean capital breeder, the southern right whale (Eubalaena australis), has been monitored over the past 43 years in their South African wintering ground. Changes in the population have been documented in the past decade, including a decreased reproductive rate and a shift in foraging strategy. To evaluate if a reduced foraging success is an underlying factor, we assessed the temporal variation in morphological body condition through aerial photogrammetry. Results showed a 23% reduction in maternal body condition, potentially contributing to the decreased reproductive rate of the population. To the best of our knowledge, this is the first study to quantify a decadal reduction in the body condition of a capital breeder dependent on Southern Ocean productivity. Understanding the bioenergetic consequences of environmental change is vital to predicting species' resilience to climate change.
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Affiliation(s)
- Els Vermeulen
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa.
| | - Terriann Thavar
- grid.49697.350000 0001 2107 2298Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Maria Glarou
- grid.14013.370000 0004 0640 0021Húsavík Research Centre, University of Iceland, 640 Húsavík, Iceland
| | - Andre Ganswindt
- grid.49697.350000 0001 2107 2298Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Fredrik Christiansen
- grid.7048.b0000 0001 1956 2722Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
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3
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McHuron EA, Adamczak S, Costa DP, Booth C. Estimating reproductive costs in marine mammal bioenergetic models: a review of current knowledge and data availability. CONSERVATION PHYSIOLOGY 2023; 11:coac080. [PMID: 36685328 PMCID: PMC9845964 DOI: 10.1093/conphys/coac080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 11/26/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Reproductive costs represent a significant proportion of a mammalian female's energy budget. Estimates of reproductive costs are needed for understanding how alterations to energy budgets, such as those from environmental variation or human activities, impact maternal body condition, vital rates and population dynamics. Such questions are increasingly important for marine mammals, as many populations are faced with rapidly changing and increasingly disturbed environments. Here we review the different energetic costs that marine mammals incur during gestation and lactation and how those costs are typically estimated in bioenergetic models. We compiled data availability on key model parameters for each species across all six marine mammal taxonomic groups (mysticetes, odontocetes, pinnipeds, sirenians, mustelids and ursids). Pinnipeds were the best-represented group regarding data availability, including estimates of milk intake, milk composition, lactation duration, birth mass, body composition at birth and growth. There were still considerable data gaps, particularly for polar species, and good data were only available across all parameters in 45% of pinniped species. Cetaceans and sirenians were comparatively data-poor, with some species having little or no data for any parameters, particularly beaked whales. Even for species with moderate data coverage, many parameter estimates were tentative or based on indirect approaches, necessitating reevaluation of these estimates. We discuss mechanisms and factors that affect maternal energy investment or prey requirements during reproduction, such as prey supplementation by offspring, metabolic compensation, environmental conditions and maternal characteristics. Filling the existing data gaps highlighted in this review, particularly for parameters that are influential on bioenergetic model outputs, will help refine reproductive costs estimated from bioenergetic models and better address how and when energy imbalances are likely to affect marine mammal populations.
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Affiliation(s)
- Elizabeth A McHuron
- Corresponding author: Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, WA, 98105, USA.
| | - Stephanie Adamczak
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Cormac Booth
- SMRU Consulting, Scottish Oceans Institute, St Andrews, UK
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4
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McHuron EA, Adamczak S, Arnould JPY, Ashe E, Booth C, Bowen WD, Christiansen F, Chudzinska M, Costa DP, Fahlman A, Farmer NA, Fortune SME, Gallagher CA, Keen KA, Madsen PT, McMahon CR, Nabe-Nielsen J, Noren DP, Noren SR, Pirotta E, Rosen DAS, Speakman CN, Villegas-Amtmann S, Williams R. Key questions in marine mammal bioenergetics. CONSERVATION PHYSIOLOGY 2022; 10:coac055. [PMID: 35949259 PMCID: PMC9358695 DOI: 10.1093/conphys/coac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/28/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Bioenergetic approaches are increasingly used to understand how marine mammal populations could be affected by a changing and disturbed aquatic environment. There remain considerable gaps in our knowledge of marine mammal bioenergetics, which hinder the application of bioenergetic studies to inform policy decisions. We conducted a priority-setting exercise to identify high-priority unanswered questions in marine mammal bioenergetics, with an emphasis on questions relevant to conservation and management. Electronic communication and a virtual workshop were used to solicit and collate potential research questions from the marine mammal bioenergetic community. From a final list of 39 questions, 11 were identified as 'key' questions because they received votes from at least 50% of survey participants. Key questions included those related to energy intake (prey landscapes, exposure to human activities) and expenditure (field metabolic rate, exposure to human activities, lactation, time-activity budgets), energy allocation priorities, metrics of body condition and relationships with survival and reproductive success and extrapolation of data from one species to another. Existing tools to address key questions include labelled water, animal-borne sensors, mark-resight data from long-term research programs, environmental DNA and unmanned vehicles. Further validation of existing approaches and development of new methodologies are needed to comprehensively address some key questions, particularly for cetaceans. The identification of these key questions can provide a guiding framework to set research priorities, which ultimately may yield more accurate information to inform policies and better conserve marine mammal populations.
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Affiliation(s)
- Elizabeth A McHuron
- Corresponding author: Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, WA, 98195, USA.
| | - Stephanie Adamczak
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Erin Ashe
- Oceans Initiative, Seattle, WA, 98102, USA
| | - Cormac Booth
- SMRU Consulting, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 8LB, UK
| | - W Don Bowen
- Biology Department, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, NS B2Y 4A2, Canada
| | - Fredrik Christiansen
- Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
- Center for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch, Murdoch University, WA 6150, Australia
| | - Magda Chudzinska
- SMRU Consulting, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 8LB, UK
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 9XL, UK
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, 46005 Valencia, Spain
- Kolmården Wildlife Park, 618 92 Kolmården, Sweden
| | - Nicholas A Farmer
- NOAA/National Marine Fisheries Service, Southeast Regional Office, St. Petersburg, FL, 33701, USA
| | - Sarah M E Fortune
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Cara A Gallagher
- Plant Ecology and Nature Conservation, University of Potsdam, 14476 Potsdam, Germany
| | - Kelly A Keen
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Clive R McMahon
- IMOS Animal Tagging, Sydney Institute of Marine Science, Mosman, NSW 2088, Australia
| | | | - Dawn P Noren
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, 98112, USA
| | - Shawn R Noren
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Enrico Pirotta
- Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St. Andrews KY16 9LZ, UK
| | - David A S Rosen
- Institute for Oceans and Fisheries, University of British Columbia, Vancouver, BC V6T 1ZA, Canada
| | - Cassie N Speakman
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Stella Villegas-Amtmann
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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5
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Smiley RA, Wagler BL, LaSharr TN, Denryter KA, Stephenson TR, Courtemanch AB, Mong TW, Lutz D, McWhirter D, Brimeyer D, Hnilicka P, Lowrey B, Monteith KL. Heterogeneity in risk‐sensitive allocation of somatic reserves in a long‐lived mammal. Ecosphere 2022. [DOI: 10.1002/ecs2.4161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rachel A. Smiley
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Brittany L. Wagler
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Tayler N. LaSharr
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | | | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife Bishop California USA
| | | | - Tony W. Mong
- Wyoming Game and Fish Department Cody Wyoming USA
| | - Daryl Lutz
- Wyoming Game and Fish Department Lander Wyoming USA
| | | | - Doug Brimeyer
- Wyoming Game and Fish Department Cheyenne Wyoming USA
| | | | - Blake Lowrey
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
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6
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Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data. Polar Biol 2022. [DOI: 10.1007/s00300-022-03058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractMarine animals such as the southern elephant seal (Mirounga leonina) rely on a productive marine environment and are vulnerable to oceanic changes that can affect their reproduction and survival rates. Davis Base, Antarctica, acts as a moulting site for southern elephant seals that forage in Prydz Bay, but the mitochondrial haplotype diversity and natal source populations of these seals have not been characterized. In this study, we combined genetic and animal tracking data on these moulting seals to identify levels of mitochondrial haplotype diversity, natal source population, and movement behaviours during foraging and haul-out periods. Using partial sequences of the mitochondrial control region, we identified two major breeding mitochondrial lineages of seals at Davis Base. We found that the majority of the seals originated from breeding stocks within the South Atlantic Ocean and South Indian Ocean. One seal was grouped with the Macquarie Island breeding stock (South Pacific Ocean). The Macquarie Island population, unlike the other two stocks, is decreasing in size. Tracking data revealed long-distance foraging activity of the Macquarie Island seal around Crozet Islands. We speculate that changes to the Antarctic marine environment can result in a shift in foraging and movement strategies, which subsequently affects seal population growth rates.
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7
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Mestre J, Authier M, Cherel Y, Harcourt R, McMahon CR, Hindell MA, Charrassin JB, Guinet C. Decadal changes in blood δ 13C values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands. Proc Biol Sci 2020; 287:20201544. [PMID: 32811318 PMCID: PMC7482287 DOI: 10.1098/rspb.2020.1544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/27/2020] [Indexed: 11/12/2022] Open
Abstract
Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004-2018) using tracking, weaning mass, and blood δ13C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006-2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers' pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood δ13C values decreased by 1.1‰ over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in δ13C is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations.
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Affiliation(s)
- Julie Mestre
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
- Sorbonne Université, Collège Doctoral, F-75005 Paris, France
| | - Matthieu Authier
- Observatoire PELAGIS, UMS 3462 La Rochelle Université and CNRS, La Rochelle, France
- ADERA, Pessac Cedex, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Rob Harcourt
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Clive R. McMahon
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- IMOS Animal Tagging, Sydney Institute of Marine Science, Sydney, NSW, Australia
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | | | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
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8
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Alekseeva GS, Loshchagina JA, Erofeeva MN, Naidenko SV. Stressed by Maternity: Changes of Cortisol Level in Lactating Domestic Cats. Animals (Basel) 2020; 10:ani10050903. [PMID: 32456071 PMCID: PMC7278448 DOI: 10.3390/ani10050903] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 12/18/2022] Open
Abstract
Lactation is the most energetically expensive component of maternal care in mammals. Increased reproductive investment can lead to physiological stress for the mothers, based on the exhaustion of energy resources and increase in glucocorticoids level. This study aimed to estimate the changes in cortisol concentrations during lactation in domestic cats and compared the differences among litter sizes. Eleven females gave birth to 27 litters, which were divided in two groups-small (1-3 kittens) and large (4-7 kittens) litters. Blood samples were collected from each female before mating, after parturition, at 4 and 8 weeks of lactation. We showed that the cortisol level in females changed significantly during lactation-the highest concentrations were observed at the peak of lactation at 4 weeks. Cortisol levels varied significantly among females but did not depend on their maternal experience. We also revealed that there were no differences in cortisol levels between females with small and large litters, but at 4 weeks of lactation, the hormone concentrations were higher in females with small litters. It is likely that these females initially invested less in reproduction, giving birth to fewer offspring.
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Affiliation(s)
- Galina S. Alekseeva
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
- Correspondence:
| | | | - Mariya N. Erofeeva
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
| | - Sergey V. Naidenko
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
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9
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Macdonald KR, Rotella JJ, Garrott RA, Link WA. Sources of variation in maternal allocation in a long-lived mammal. J Anim Ecol 2020; 89:1927-1940. [PMID: 32356304 PMCID: PMC7497196 DOI: 10.1111/1365-2656.13243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 04/09/2020] [Indexed: 12/03/2022]
Abstract
Life history theory predicts allocation of energy to reproduction varies with maternal age, but additional maternal features may be important to the allocation of energy to reproduction. We aimed to characterize age‐specific variation in maternal allocation and assess the relationship between maternal allocation and other static and dynamic maternal features. Mass measurements of 531 mothers and pups were used with Bayesian hierarchical models to explain the relationship between diverse maternal attributes and both the proportion of mass allocated by Weddell seal mothers, and the efficiency of mass transfer from mother to pup during lactation as well as the weaning mass of pups. Our results demonstrated that maternal mass was strongly and positively associated with the relative reserves allocated by a mother and a pup's weaning mass but that the efficiency of mass transfer declines with maternal parturition mass. Birthdate was positively associated with proportion mass allocation and pup weaning mass, but mass transfer efficiency was predicted to be highest at the mean birthdate. The relative allocation of maternal reserves declined with maternal age but the efficiency of mass transfer to pups increases, suggestive of selective disappearance of poor‐quality mothers. These findings highlight the importance of considering multiple maternal features when assessing variation in maternal allocation.
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Affiliation(s)
| | - Jay J Rotella
- Ecology Deptartment, Montana State University, Bozeman, MT, USA
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10
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Smout S, King R, Pomeroy P. Environment-sensitive mass changes influence breeding frequency in a capital breeding marine top predator. J Anim Ecol 2019; 89:384-396. [PMID: 31749170 DOI: 10.1111/1365-2656.13128] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/23/2019] [Indexed: 01/21/2023]
Abstract
The trade-off between survival and reproduction in resource-limited iteroparous animals can result in some individuals missing some breeding opportunities. In practice, even with the best observation regimes, deciding whether 'missed' years represent real pauses in breeding or failures to detect breeding can be difficult, posing problems for the estimation of individual reproductive output and overall population fecundity. We corrected fecundity estimates by determining whether breeding had occurred in skipped years, using long-term capture-recapture observation datasets with parallel longitudinal mass measurements, based on informative underlying relationships between individuals' mass, breeding status and environmental drivers in a capital breeding phocid, the grey seal. Bayesian modelling considered interacting processes jointly: temporal changes in a phenotypic covariate (mass); relationship of mass to breeding probability; effects of maternal breeding state and mark type on resighting. Full reproductive histories were imputed, with the status of unobserved animals estimated as breeding or non-breeding, accounting for local environmental variation. Overall fecundity was then derived for Scottish breeding colonies with contrasting pup production trends. Maternal mass affected breeding likelihood. Mothers with low body mass at the end of breeding were less likely to bear a pup the following year. Successive breeding episodes incurred a cost in reduced body mass which was more pronounced for North Rona, Outer Hebrides (NR) mothers. Skipping breeding increased subsequent pupping probability substantially for low mass females. Poor environmental conditions were associated with declines in breeding probability at both colonies. Seal mass gain between breeding seasons was (a) negatively associated with lagged North Atlantic Oscillation for seals at NR and (b) positively associated with an index of seal prey (Ammodytes spp) abundance at Isle of May, Firth of Forth (IM). Overall fecundity was marginally greater at IM (increasing/stable pup production) than at NR (decreasing). No effects of mass were detected on maternal survival. Skipping breeding in female grey seals appears to be an individual mass-dependent constraint moderated by previous reproductive output and local environmental conditions. Different demographic trends at breeding colonies were consistent with the fecundities estimated using this method, which is general and adaptable to other situations.
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Affiliation(s)
| | - Ruth King
- School of Mathematics, University of Edinburgh, James Clark Maxwell Building, The King's Buildings, Edinburgh, UK
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11
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Oosthuizen WC, Postma M, Altwegg R, Nevoux M, Pradel R, Bester MN, Bruyn PJN. Individual heterogeneity in life‐history trade‐offs with age at first reproduction in capital breeding elephant seals. POPUL ECOL 2019. [DOI: 10.1002/1438-390x.12015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- W. Chris Oosthuizen
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Hatfield South Africa
| | - Martin Postma
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Hatfield South Africa
| | - Res Altwegg
- Centre for Statistics in Ecology Environment and Conservation, Department of Statistical Sciences University of Cape Town Rondebosch South Africa
- African Climate and Development Initiative, University of Cape Town Rondebosch South Africa
| | - Marie Nevoux
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Hatfield South Africa
- UMRESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRA Rennes France
| | - Roger Pradel
- Biostatistics and Population Biology Group, CEFE, CNRS, University of Montpellier Montpellier France
| | - Marthán N. Bester
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Hatfield South Africa
| | - P. J. Nico Bruyn
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Hatfield South Africa
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12
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Salogni E, Galimberti F, Sanvito S, Miller E. Male and female pups of the highly sexually dimorphic northern elephant seal (Mirounga angustirostris) differ slightly in body size. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In mammals, males generally are larger than females, though such sexual-size differences have been documented primarily in adults and are relatively poorly known in early life. We studied sexual-size differences in pups of the northern elephant seal (Mirounga angustirostris (Gill, 1866)), which in adulthood is one of the most sexually dimorphic mammals. We studied body size at birth and weaning, at Islas San Benito, Mexico, at the southernmost limit of the species’ breeding range. Males were 10% heavier and 2% longer than females at birth. Sexes did not differ significantly in either measure of body size at weaning, although males were slightly heavier (4%) and longer (1%) than females. Neither growth rate nor suckling duration differed between the sexes. In previous studies in California, USA, pups at weaning were heavier than in our study, and males were heavier than females. These differences may reflect ecological, temporal, or life-history differences across populations. The modest difference in sexual-size dimorphism early in life in this species compared with the great difference in adulthood likely reflects multiple selective forces, including constraints on neonatal size set by body size of females, and the weakness of sexual selection at that stage of life.
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Affiliation(s)
- E. Salogni
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada
- Elephant Seal Research Group, Sea Lion Island, Falkland Islands, FIQQ 1ZZ
| | - F. Galimberti
- Elephant Seal Research Group, Sea Lion Island, Falkland Islands, FIQQ 1ZZ
| | - S. Sanvito
- Elephant Seal Research Group, Sea Lion Island, Falkland Islands, FIQQ 1ZZ
| | - E.H. Miller
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada
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13
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Griffen BD. Reproductive skipping as an optimal life history strategy in the southern elephant seal, Mirounga leonina. Ecol Evol 2018; 8:9158-9170. [PMID: 30377491 PMCID: PMC6194220 DOI: 10.1002/ece3.4408] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 11/19/2022] Open
Abstract
Intermittent breeding by which organisms skip some current reproductive opportunities in order to enhance future reproductive success is a common life history trade-off among long-lived, iteroparous species. The southern elephant seal Mirounga leonina engages in intermediate breeding when body condition is low. While it is anticipated that this strategy may increase the lifetime reproductive output of this species, the conditions under which reproductive skipping are predicted to occur are not clear. Here I develop a dynamic state variable model based on published data that examines when southern elephant seals are predicted to optimally skip reproduction in order to maximize lifetime reproductive output as a function of current body mass, maternal age, and survivorship. I demonstrate that the optimal reproductive strategy for this species can include reproductive skipping, and that the conditions where this is optimal depend on patterns of mass-dependent adult female survival. I further show that intermittent breeding can increase lifetime reproductive output, and that the magnitude of this benefit increases with the ability of individual animals to replenish depleted body mass through foraging. Finally, I show that when the environment is variable and foraging is reduced in bad years, the benefit of adopting an optimal strategy that includes reproductive skipping increases asymptotically with the frequency of bad years. These results highlight the importance of characterizing the pattern of adult survival in this species, as well as the need to identify other factors that may influence the prevalence and benefits of reproductive skipping.
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Karniski C, Krzyszczyk E, Mann J. Senescence impacts reproduction and maternal investment in bottlenose dolphins. Proc Biol Sci 2018; 285:20181123. [PMID: 30051841 PMCID: PMC6083244 DOI: 10.1098/rspb.2018.1123] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 06/22/2018] [Indexed: 01/13/2023] Open
Abstract
Reproductive senescence is evident across many mammalian species. An emerging perspective considers components of reproductive senescence as evolutionarily distinct phenomena: fertility senescence and maternal-effect senescence. While fertility senescence is regarded as the ageing of reproductive physiology, maternal-effect senescence pertains to the declining capacity to provision and rear surviving offspring due to age. Both contribute to reproductive failure in utero making it difficult to differentiate between the two prenatally in the wild. We investigated both components in a long-lived mammal with prolonged maternal care through three parameters: calf survival, interbirth interval (IBI) and lactation period. We provide clear evidence for reproductive senescence in a wild population of bottlenose dolphins (Tursiops aduncus) using 34+ years of longitudinal data on 229 adult females and 562 calves. Calf survival decreased with maternal age, and calves with older mothers had lower survival than predicted by birth order, suggesting maternal-effect senescence. Both lactation period and IBIs increased with maternal age, and IBIs increased regardless of calf mortality, indicating interactions between fertility and maternal-effect senescence. Of calves that survived to weaning, last-born calves weaned later than earlier-born calves, evidence of terminal investment, a mitigating strategy given reduced reproductive value caused by either components of reproductive senescence.
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Affiliation(s)
- Caitlin Karniski
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | - Ewa Krzyszczyk
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | - Janet Mann
- Department of Biology, Georgetown University, Washington, DC 20057, USA
- Department of Psychology, Georgetown University, Washington, DC 20057, USA
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15
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Goedegebuure M, Melbourne-Thomas J, Corney SP, McMahon CR, Hindell MA. Modelling southern elephant seals Mirounga leonina using an individual-based model coupled with a dynamic energy budget. PLoS One 2018; 13:e0194950. [PMID: 29596456 PMCID: PMC5875804 DOI: 10.1371/journal.pone.0194950] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/13/2018] [Indexed: 01/08/2023] Open
Abstract
Higher trophic-level species are an integral component of any marine ecosystem. Despite their importance, methods for representing these species in end-to-end ecosystem models often have limited representation of life histories, energetics and behaviour. We built an individual-based model coupled with a dynamic energy budget for female southern elephant seals Mirounga leonina to demonstrate a method for detailed representation of marine mammals. We aimed to develop a model which could i) simulate energy use and life histories, as well as breeding traits of southern elephant seals in an emergent manner, ii) project a stable population over time, and iii) have realistic population dynamics and structure based on emergent life history features (such as age at first breeding, lifespan, fecundity and (yearling) survival). We evaluated the model's ability to represent a stable population over long time periods (>10 generations), including the sensitivity of the emergent properties to variations in key parameters. Analyses indicated that the model is sensitive to changes in resource availability and energy requirements for the transition from pup to juvenile, and juvenile to adult stage. This was particularly the case for breeding success and yearling survival. This model is suitable for use as a standalone tool for investigating the impacts of changes to behaviour and population responses of southern elephant seals.
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Affiliation(s)
- Merel Goedegebuure
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
| | - Jessica Melbourne-Thomas
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
- Australian Antarctic Division, Channel Highway, Kingston Tasmania 7050 Australia
| | - Stuart P. Corney
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
| | - Clive R. McMahon
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, New South Wales 2088, Australia
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7000 Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7000 Australia
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Desprez M, Gimenez O, McMahon CR, Hindell MA, Harcourt RG. Optimizing lifetime reproductive output: Intermittent breeding as a tactic for females in a long-lived, multiparous mammal. J Anim Ecol 2017; 87:199-211. [PMID: 29063588 DOI: 10.1111/1365-2656.12775] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 10/11/2017] [Indexed: 11/30/2022]
Abstract
In iteroparous species, intermittent breeding is an important life-history tactic that can greatly affect animal population growth and viability. Despite its importance, few studies have quantified the consequences of breeding pauses on lifetime reproductive output, principally because calculating lifetime reproductive output requires knowledge of each individual's entire reproductive history. This information is extremely difficult to obtain in wild populations. We applied novel statistical approaches that account for uncertainty in state assessment and individual heterogeneity to an 18-year capture-recapture dataset of 6,631 female southern elephant seals from Macquarie Island. We estimated survival and breeding probabilities, and investigated the consequences of intermittent breeding on lifetime reproductive output. We found consistent differences in females' demographic performance between two heterogeneity classes. In particular, breeding imbued a high cost on survival in the females from the heterogeneity class 2, assumed to be females of lower quality. Individual quality also appeared to play a major role in a female's decision to skip reproduction with females of poorer quality more likely to skip breeding events than females of higher quality. Skipping some breeding events allowed females from both heterogeneity classes to increase lifetime reproductive output over females that bred annually. However, females of lower quality produced less offspring over their lifetime. Intermittent breeding seems to be used by female southern elephant seals as a tactic to offset reproductive costs on survival and enhance lifetime reproductive output but remains unavoidable and driven by individual-specific constraints in some other females.
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Affiliation(s)
- Marine Desprez
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Olivier Gimenez
- CEFE UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier Cedex 5, France
| | | | - Mark A Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
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17
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Ronget V, Gaillard JM, Coulson T, Garratt M, Gueyffier F, Lega JC, Lemaître JF. Causes and consequences of variation in offspring body mass: meta-analyses in birds and mammals. Biol Rev Camb Philos Soc 2017; 93:1-27. [DOI: 10.1111/brv.12329] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/23/2017] [Accepted: 03/03/2017] [Indexed: 01/27/2023]
Affiliation(s)
- Victor Ronget
- Univ Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive; F-69622 Villeurbanne France
| | - Jean-Michel Gaillard
- Univ Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive; F-69622 Villeurbanne France
| | - Tim Coulson
- Department of Zoology; University of Oxford; Oxford OX13PS U.K
| | - Michael Garratt
- Department of Pathology; University of Michigan Medical School; Ann Arbor MI 48109 U.S.A
| | - François Gueyffier
- Univ Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive; F-69622 Villeurbanne France
| | - Jean-Christophe Lega
- Univ Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive; F-69622 Villeurbanne France
| | - Jean-François Lemaître
- Univ Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive; F-69622 Villeurbanne France
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18
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Clausius E, McMahon CR, Hindell MA. Five decades on: Use of historical weaning size data reveals that a decrease in maternal foraging success underpins the long-term decline in population of southern elephant seals (Mirounga leonina). PLoS One 2017; 12:e0173427. [PMID: 28301546 PMCID: PMC5354283 DOI: 10.1371/journal.pone.0173427] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/19/2017] [Indexed: 01/31/2023] Open
Abstract
The population of Southern elephant seals (Mirounga leonina) at Macquarie Island has declined since the 1960s, and is thought to be due to changing oceanic conditions leading to reductions in the foraging success of Macquarie Island breeding females. To test this hypothesis, we used a 55-year-old data set on weaning size of southern elephant seals to quantify a decrease in weaning size from a period of population stability in 1950s to its present state of on-going decline. Being capital breeders, the size of elephant seal pups at weaning is a direct consequence of maternal foraging success in the preceding year. During the 1940-1950s, the mean of female pups at weaning was similar between the Heard and Macquarie Island populations, while the snout-tail-length length of male weaners from Heard Island were longer than their conspecifics at Macquarie Island. Additionally, the snout-tail-length of pups at weaning decreased by 3cm between the 1950s and 1990s in the Macquarie Island population, concurrent with the observed population decline. Given the importance of weaning size in determining first-year survival and recruitment rates, the decline in the size at weaning suggests that the decline in the Macquarie Island population has, to some extent, been driven by reduced maternal foraging success, consequent declines in the size of pups at weaning, leading to reduced first-year survival rates and recruitment of breeding females into the population 3 to 4 years later.
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Affiliation(s)
- Ella Clausius
- Centre for Ecology and Biodiversity, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Clive R. McMahon
- Sydney Institute of Marine Science, Mosman, New South Wales, Australia
| | - Mark A. Hindell
- Centre for Ecology and Biodiversity, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart, Tasmania, Australia
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19
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McMahon CR, Harcourt RG, Burton HR, Daniel O, Hindell MA. Seal mothers expend more on offspring under favourable conditions and less when resources are limited. J Anim Ecol 2017; 86:359-370. [PMID: 27859273 DOI: 10.1111/1365-2656.12611] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 11/02/2016] [Indexed: 01/29/2023]
Abstract
In mammals, maternal expenditure on offspring is a complex mix of several factors including the species' mating system, offspring sex and the condition and age of the mother. While theory suggests that in polygynous species mothers should wean larger male offspring than females when resources and maternal conditions allow, the evidence for this remains equivocal. Southern elephant seals are highly dimorphic, polygynous capital breeders existing in an environment with highly variable resources and should therefore provide clear evidence to support the theoretical expectations of differential maternal expenditure in male and female pups. We quantified maternal size (mass and length) and pup size at birth and weaning for 342 elephant seal mothers at Macquarie Island. The study was conducted over 11 years of contrasting sea-ice and Southern Annular Mode values, both indices of maternal prey resources. Overall, large females weaned male pups that weighed 17 kg (15·5%) more than female pups. Maternal condition varied by as much as 59 kg among years, and was positively related to Southern Annular Mode, and negatively to maximum sea-ice extent. Smaller mothers weaned relatively larger male pups under favourable conditions, this effect was less apparent for larger mothers. We developed a simple model linking environmental variation to maternal masses post-partum, followed by maternal masses post-partum to weaning masses and then weaning masses to pup survival and demonstrated that environmental conditions affected predicted survival so that the pups of small mothers had an estimated 7% increase in first year survival in 'good' vs. 'bad' years compared to 1% for female pups of large mothers. Co-occurrence of environmental quality and conservative reproductive tactics suggests that mothers retain substantial plasticity in maternal care, enhancing their lifetime reproductive success by adjusting reproductive expenditure relative to both prevailing environmental conditions and their own capabilities.
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Affiliation(s)
- Clive R McMahon
- Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.,Institute of Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, TAS, 7000, Australia.,Marine Predator Research Group, Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Harry R Burton
- Australian Antarctic Division, Channel Highway, Kingston, TAS, 7050, Australia
| | - Owen Daniel
- Institute of Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, TAS, 7000, Australia
| | - Mark A Hindell
- Institute of Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, TAS, 7000, Australia.,Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, TAS, 7000, Australia
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20
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Paterson JT, Rotella JJ, Mannas JM, Garrott RA. Patterns of age‐related change in reproductive effort differ in the pre‐natal and post‐natal periods in a long‐lived mammal. J Anim Ecol 2016; 85:1540-1551. [DOI: 10.1111/1365-2656.12577] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 07/13/2016] [Indexed: 11/30/2022]
Affiliation(s)
- John T. Paterson
- Ecology Department Montana State University Bozeman MT 59717 USA
| | - Jay J. Rotella
- Ecology Department Montana State University Bozeman MT 59717 USA
| | - Jennifer M. Mannas
- Ecology Department Montana State University Bozeman MT 59717 USA
- Progressive Animal Welfare Society Lynnwood WA 98046 USA
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21
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Hindell MA, McMahon CR, Bester MN, Boehme L, Costa D, Fedak MA, Guinet C, Herraiz‐Borreguero L, Harcourt RG, Huckstadt L, Kovacs KM, Lydersen C, McIntyre T, Muelbert M, Patterson T, Roquet F, Williams G, Charrassin J. Circumpolar habitat use in the southern elephant seal: implications for foraging success and population trajectories. Ecosphere 2016. [DOI: 10.1002/ecs2.1213] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Mark A. Hindell
- Institute for Marine and Antarctic Studies University of Tasmania Hobart Tasmania 7001 Australia
- Antarctic Climate & Ecosystem Cooperative Research Centre University of Tasmania Hobart Tasmania 7001 Australia
| | - Clive R. McMahon
- Institute for Marine and Antarctic Studies University of Tasmania Hobart Tasmania 7001 Australia
- Sydney Institute of Marine Science 19 Chowder Bay Road Mosman New South Wales 2088 Australia
| | - Marthán N. Bester
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Private Bag X20 Hatfield 0028 South Africa
| | - Lars Boehme
- Sea Mammal Research Unit Scottish Oceans Institute University of St Andrews St Andrews UK
| | - Daniel Costa
- Department of Ecology and Evolutionary Biology University of California Santa Cruz California USA
| | - Mike A. Fedak
- Sea Mammal Research Unit Scottish Oceans Institute University of St Andrews St Andrews UK
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé Centre National de la Recherche Scientifique Villiers en Bois France
| | - Laura Herraiz‐Borreguero
- Antarctic Climate & Ecosystem Cooperative Research Centre University of Tasmania Hobart Tasmania 7001 Australia
- Centre for Ice and Climate Niels Bohr Institute University of Copenhagen Copenhagen Denmark
| | - Robert G. Harcourt
- Department of Biological Sciences Macquarie University Sydney New South Wales 2109 Australia
| | - Luis Huckstadt
- Department of Ecology and Evolutionary Biology University of California Santa Cruz California USA
| | - Kit M. Kovacs
- Norwegian Polar Institute Fram Centre Tromsø N‐9296 Norway
| | | | - Trevor McIntyre
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Private Bag X20 Hatfield 0028 South Africa
| | - Monica Muelbert
- Instituto de Oceanografia Universidade Federal do Rio Grande Porto Alegre Brazil
| | - Toby Patterson
- CSIRO Wealth from Oceans Research Flagship and Marine & Atmospheric Research GPO Box 1538 Hobart Tasmania 7001 Australia
| | - Fabien Roquet
- Department of Meteorology Stockholm University Stockholm Sweden
| | - Guy Williams
- Antarctic Climate & Ecosystem Cooperative Research Centre University of Tasmania Hobart Tasmania 7001 Australia
| | - Jean‐Benoit Charrassin
- Laboratoire d'Océanographie et du Climat: Expérimentation et Approches Numériques Paris France
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22
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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] [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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23
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McMahon CR, New LF, Fairley EJ, Hindell MA, Burton HR. The effects of body size and climate on post‐weaning survival of elephant seals at
H
eard
I
sland. J Zool (1987) 2015. [DOI: 10.1111/jzo.12279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. R. McMahon
- Sydney Institute of Marine Science Mosman NSW Australia
- Australian Antarctic Division Hobart Tas. Australia
| | - L. F. New
- US Marine Mammal Commission Bethesda MD USA
- USGS Patuxent Wildlife Research Center Laurel MD USA
- Washington State University Vancouver WA USA
| | | | - M. A. Hindell
- Institute for Marine and Antarctic Studies University of Tasmania Hobart Tas. Australia
| | - H. R. Burton
- Australian Antarctic Division Hobart Tas. Australia
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24
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Oosthuizen WC, Bester MN, Altwegg R, McIntyre T, de Bruyn PJN. Decomposing the variance in southern elephant seal weaning mass: partitioning environmental signals and maternal effects. Ecosphere 2015. [DOI: 10.1890/es14-00508.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Fowler MA, Costa DP, Crocker DE, Shen WJ, Kraemer FB. Adipose Triglyceride Lipase, Not Hormone-Sensitive Lipase, Is the Primary Lipolytic Enzyme in Fasting Elephant Seals (Mirounga angustirostris). Physiol Biochem Zool 2015; 88:284-94. [PMID: 25860827 DOI: 10.1086/680079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Little is known about the mechanisms that allow capital breeders to rapidly mobilize large amounts of body reserves. Northern elephant seals (Mirounga angustirostris) utilize fat reserves for maternal metabolism and to create high fat milk for the pup. Hormone-sensitive lipase (HSL) has been hypothesized to be an important lipolytic enzyme in fasting seals, but the activity of HSL and adipose triglyceride lipase (ATGL) has not been quantified in fasting adult seals, nor has their relationship to milk lipid content been assessed. Blubber and milk samples were obtained from 18 early lactation and 19 late lactation females, as well as blubber from five early and five late molting female seals. Blubber lipolytic activity was assessed with radiometric assays. HSL activity was negligible in seal blubber at all fasting stages. Total triglyceride lipase activity was stable among early and late lactation and early molt but increased in late molting seals. Relative abundance of ATGL protein increased across fasting, but neither activity nor relative protein levels were related to circulating nonesterified fatty acids or milk lipid content, suggesting the possibility of other regulatory pathways between lipolytic activity and milk lipid content. These results demonstrate that HSL is not the primary lipolytic enzyme in fasting adult female seals and that ATGL contributes more to lipolysis than HSL.
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Affiliation(s)
- Melinda A Fowler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California; 2Department of Biology, Sonoma State University, Rohnert Park, California; 3Division of Endocrinology, Gerontology, and Metabolism, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, California
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26
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Gélin U, Wilson ME, Coulson G, Festa-Bianchet M. Experimental manipulation of female reproduction demonstrates its fitness costs in kangaroos. J Anim Ecol 2014; 84:239-48. [DOI: 10.1111/1365-2656.12266] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/30/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Uriel Gélin
- Département de biologie; Université de Sherbrooke; 2500 boulevard de l'université; Sherbrooke QC J1K 2R1 Canada
| | - Michelle E. Wilson
- Department of Zoology; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Graeme Coulson
- Department of Zoology; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Marco Festa-Bianchet
- Département de biologie; Université de Sherbrooke; 2500 boulevard de l'université; Sherbrooke QC J1K 2R1 Canada
- Department of Zoology; The University of Melbourne; Melbourne Vic. 3010 Australia
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27
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Walters A, Lea MA, van den Hoff J, Field IC, Virtue P, Sokolov S, Pinkerton MH, Hindell MA. Spatially explicit estimates of prey consumption reveal a new krill predator in the Southern Ocean. PLoS One 2014; 9:e86452. [PMID: 24516515 PMCID: PMC3905967 DOI: 10.1371/journal.pone.0086452] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 12/15/2013] [Indexed: 02/05/2023] Open
Abstract
Development in foraging behaviour and dietary intake of many vertebrates are age-structured.
Differences in feeding ecology may correlate with ontogenetic shifts in dispersal patterns, and
therefore affect foraging habitat and resource utilization. Such life-history traits have important
implications in interpreting tropho-dynamic linkages. Stable isotope ratios in the whiskers of
sub-yearling southern elephant seals (Mirounga leonina;
n = 12) were used, in conjunction with satellite telemetry and environmental
data, to examine their foraging habitat and diet during their first foraging migration. The trophic
position of seals from Macquarie Island (54°30′S, 158°57′E) was estimated using
stable carbon (δ13C) and nitrogen (δ15N) ratios along the
length of the whisker, which provided a temporal record of prey intake. Satellite-relayed data
loggers provided details on seal movement patterns, which were related to isotopic concentrations
along the whisker. Animals fed in waters south of the Polar Front (>60°S) or within
Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Statistical Subareas
88.1 and 88.2, as indicated by both their depleted δ13C
(<−20‰) values, and tracking data. They predominantly exploited varying proportions
of mesopelagic fish and squid, and crustaceans, such as euphausiids, which have not been reported as
a prey item for this species. Comparison of isotopic data between sub-yearlings, and 1, 2 and 3 yr
olds indicated that sub-yearlings, limited by their size, dive capabilities and prey capture skills
to feeding higher in the water column, fed at a lower trophic level than older seals. This is
consistent with the consumption of euphausiids and most probably, Antarctic krill (Euphausia
superba), which constitute an abundant, easily accessible source of prey in water masses
used by this age class of seals. Isotopic assessment and concurrent tracking of seals are
successfully used here to identify ontogenetic shifts in broad-scale foraging habitat use and diet
preferences in a highly migratory predator.
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Affiliation(s)
- Andrea Walters
- Institute for Marine and Antarctic Studies, University of
Tasmania, Hobart, Tasmania, Australia
- Antarctic Climate and Ecosystems Cooperative Research
Centre, Hobart, Tasmania, Australia
- * E-mail:
| | - Mary-Anne Lea
- Institute for Marine and Antarctic Studies, University of
Tasmania, Hobart, Tasmania, Australia
| | | | - Iain C. Field
- Marine Mammal Research Group, Department of Environment
and Geography, Macquarie University, Sydney, New South Wales, Australia
| | - Patti Virtue
- Institute for Marine and Antarctic Studies, University of
Tasmania, Hobart, Tasmania, Australia
- Antarctic Climate and Ecosystems Cooperative Research
Centre, Hobart, Tasmania, Australia
| | - Sergei Sokolov
- Commonwealth Scientific and Industrial Research
Organisation Marine and Atmospheric Research, Hobart, Tasmania, Australia
| | - Matt H. Pinkerton
- National Institute of Water and Atmospheric Research Ltd,
Kilbernie, Wellington, New Zealand
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of
Tasmania, Hobart, Tasmania, Australia
- Antarctic Climate and Ecosystems Cooperative Research
Centre, Hobart, Tasmania, Australia
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28
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Richard G, Vacquié-Garcia J, Jouma'a J, Picard B, Génin A, Arnould JPY, Bailleul F, Guinet C. Variation in body condition during the post-moult foraging trip of southern elephant seals and its consequences on diving behaviour. J Exp Biol 2014; 217:2609-19. [DOI: 10.1242/jeb.088542] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Mature female southern elephant seals come ashore only in October to breed and in January to moult, spending the rest of the year foraging at sea. Mature females may lose as much as 50% of their body mass, mostly in lipid stores, during the breeding season due to fasting and lactation. When departing to sea, post-breeding females are negatively buoyant and the relative change in body condition (i.e. density) during the foraging trip has previously been assessed by monitoring descent rate during drift dives. However, relatively few drift dives are performed resulting in low resolution of the temporal reconstruction of body condition change. In this study, six post-breeding females were instrumented with time-depth recorders and accelerometers to investigate whether changes in active swimming effort and speed could be used as an alternative method of monitoring density variations throughout the foraging trip. In addition, we assessed consequences of density change on the swimming effort of individuals while diving and effects on dive duration. Both descent swimming speed and ascent swimming effort were found to be strongly correlated to descent rate during drift dives, enabling the fine-scale monitoring of seal density change over the whole trip. Negatively buoyant seals minimized swimming effort during descents, gliding down at slower speeds, and reduced their ascent swimming effort to maintain a nearly constant swimming speed as their buoyancy increased. One percent of seal density variation over time was found to induce a 20% variation in swimming effort during dives with direct consequences on dive duration.
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29
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Postma M, Bester MN, de Bruyn PJN. Age-related reproductive variation in a wild marine mammal population. Polar Biol 2013. [DOI: 10.1007/s00300-013-1298-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Thompson ME, Muller MN, Wrangham RW. The energetics of lactation and the return to fecundity in wild chimpanzees. Behav Ecol 2012. [DOI: 10.1093/beheco/ars107] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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31
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Crocker DE, Houser DS, Webb PM. Impact of Body Reserves on Energy Expenditure, Water Flux, and Mating Success in Breeding Male Northern Elephant Seals. Physiol Biochem Zool 2012; 85:11-20. [DOI: 10.1086/663634] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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32
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Garrott RA, Rotella JJ, Siniff DB, Parkinson CL, Stauffer GE. Environmental variation and cohort effects in an Antarctic predator. OIKOS 2011. [DOI: 10.1111/j.1600-0706.2011.19673.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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33
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Aoki K, Watanabe YY, Crocker DE, Robinson PW, Biuw M, Costa DP, Miyazaki N, Fedak MA, Miller PJO. Northern elephant seals adjust gliding and stroking patterns with changes in buoyancy: validation of at-sea metrics of body density. ACTA ACUST UNITED AC 2011; 214:2973-87. [PMID: 21832140 DOI: 10.1242/jeb.055137] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many diving animals undergo substantial changes in their body density that are the result of changes in lipid content over their annual fasting cycle. Because the size of the lipid stores reflects an integration of foraging effort (energy expenditure) and foraging success (energy assimilation), measuring body density is a good way to track net resource acquisition of free-ranging animals while at sea. Here, we experimentally altered the body density and mass of three free-ranging elephant seals by remotely detaching weights and floats while monitoring their swimming speed, depth and three-axis acceleration with a high-resolution data logger. Cross-validation of three methods for estimating body density from hydrodynamic gliding performance of freely diving animals showed strong positive correlation with body density estimates obtained from isotope dilution body composition analysis over density ranges of 1015 to 1060 kg m(-3). All three hydrodynamic models were within 1% of, but slightly greater than, body density measurements determined by isotope dilution, and therefore have the potential to track changes in body condition of a wide range of freely diving animals. Gliding during ascent and descent clearly increased and stroke rate decreased when buoyancy manipulations aided the direction of vertical transit, but ascent and descent speed were largely unchanged. The seals adjusted stroking intensity to maintain swim speed within a narrow range, despite changes in buoyancy. During active swimming, all three seals increased the amplitude of lateral body accelerations and two of the seals altered stroke frequency in response to the need to produce thrust required to overcome combined drag and buoyancy forces.
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Affiliation(s)
- Kagari Aoki
- Sea Mammal Research Unit, Scottish Oceans Institute, University of Saint Andrews, Saint Andrews, Fife KY16 8LB, UK
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34
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Abstract
Marine mammals conform to the general mammalian reproductive system centered on the hypothalamic-pituitary-gonadal axis. Most marine mammals are long-lived and of large body size with lesser reproductive rates than many other animals, a consequence of their interaction with the marine environment where the demands of acquiring resources from the ocean must be balanced with the need for bearing offspring in a suitable place for survival. The degree of spatial and temporal separation of these life history phases in many species is a key feature of their ecology. The reproductive physiology of pinnipeds, cetaceans, sirenians, sea otters and polar bears has been more thoroughly characterized for the more accessible species.
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Affiliation(s)
- P Pomeroy
- NERC Sea Mammal Research Unit, University of St Andrews, St Andrews, UK
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35
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Harcourt RG, Turner E, Hall A, Waas JR, Hindell M. Effects of capture stress on free-ranging, reproductively active male Weddell seals. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2010; 196:147-54. [DOI: 10.1007/s00359-009-0501-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 12/15/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
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36
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Hoffman JI, Forcada J. Genetic Analysis of Twinning in Antarctic Fur Seals (Arctocephalus gazella). J Mammal 2009. [DOI: 10.1644/08-mamm-a-264r1.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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37
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Ailsa J. H, Bernie J. M, Richard J. B. Factors affecting first-year survival in grey seals and their implications for life history strategy. J Anim Ecol 2008. [DOI: 10.1111/j.1365-2656.2001.00468.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Dowell SA, Boren LJ, Negro SS, Muller CG, Caudron AK, Gemmell NJ. Rearing two New Zealand fur seal (Arctocephalus forsteri) pups to weaning. AUST J ZOOL 2008. [DOI: 10.1071/zo07063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The rearing of two pups to weaning is a rare occurrence in pinnipeds and in many cases it remains unknown whether it is a result of twinning or fostering. This study followed two cases where female New Zealand fur seals (Arctocephalus forsteri) raised two pups, at a colony in Kaikoura, New Zealand. Maternal attendance behaviour was observed, mass and condition of the pups were measured and genetic samples were collected to assess relatedness. In one case, the female gave birth to twins, while the other case was found to be fostering of a second pup. In both cases, the filial pups of each female exhibited significantly lower mass, condition and growth rates than the colony average. The twins’ mother reared both pups to weaning and did not appear to spend a different amount of time ashore compared with single-pup mothers. The current study confirms both fostering and twinning in New Zealand fur seals, with the potential for successfully raising the pups to weaning, despite their well developed recognition system and the energy costs involved.
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39
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Therrien JF, Côté SD, Festa-Bianchet M, Ouellet JP. Maternal care in white-tailed deer: trade-off between maintenance and reproduction under food restriction. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.04.030] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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Luque SP, Miller EH, Arnould JP, Chambellant M, Guinet C. Ontogeny of body size and shape of Antarctic and subantarctic fur seals. CAN J ZOOL 2007. [DOI: 10.1139/z07-092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic ( Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic ( Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age.
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Affiliation(s)
- Sebastián P. Luque
- Department of Biology, Memorial University, St. John’s, NL A1B 3X9, Canada
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
- Centre d’Études Biologique de Chizé, Centre National de la Recherche Scientifique (CNRS) Unité Propre 1934, 79 360 Villiers en Bois, France
| | - Edward H. Miller
- Department of Biology, Memorial University, St. John’s, NL A1B 3X9, Canada
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
- Centre d’Études Biologique de Chizé, Centre National de la Recherche Scientifique (CNRS) Unité Propre 1934, 79 360 Villiers en Bois, France
| | - John P.Y. Arnould
- Department of Biology, Memorial University, St. John’s, NL A1B 3X9, Canada
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
- Centre d’Études Biologique de Chizé, Centre National de la Recherche Scientifique (CNRS) Unité Propre 1934, 79 360 Villiers en Bois, France
| | - Magaly Chambellant
- Department of Biology, Memorial University, St. John’s, NL A1B 3X9, Canada
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
- Centre d’Études Biologique de Chizé, Centre National de la Recherche Scientifique (CNRS) Unité Propre 1934, 79 360 Villiers en Bois, France
| | - Christophe Guinet
- Department of Biology, Memorial University, St. John’s, NL A1B 3X9, Canada
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
- Centre d’Études Biologique de Chizé, Centre National de la Recherche Scientifique (CNRS) Unité Propre 1934, 79 360 Villiers en Bois, France
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41
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Proffitt KM, Garrott RA, Rotella JJ, Wheatley KE. Environmental and senescent related variations in Weddell seal body mass: implications for age-specific reproductive performance. OIKOS 2007. [DOI: 10.1111/j.0030-1299.2007.16139.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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42
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Galimberti F, Sanvito S, Braschi C, Boitani L. The cost of success: reproductive effort in male southern elephant seals (Mirounga leonina). Behav Ecol Sociobiol 2007. [DOI: 10.1007/s00265-007-0450-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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43
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Influence of maternal characteristics and oceanographic conditions on survival and recruitment probabilities of Weddell seals. OIKOS 2007. [DOI: 10.1111/j.0030-1299.2007.15528.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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44
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Exploring Linkages between Abiotic Oceanographic Processes and a Top-trophic Predator in an Antarctic Ecosystem. Ecosystems 2007. [DOI: 10.1007/s10021-006-9003-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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45
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Dahle B, Zedrosser A, Swenson JE. Correlates with body size and mass in yearling brown bears (Ursus arctos). J Zool (1987) 2006. [DOI: 10.1111/j.1469-7998.2006.00127.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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McMahon CR, Burton HR. Climate change and seal survival: evidence for environmentally mediated changes in elephant seal, Mirounga leonina, pup survival. Proc Biol Sci 2005; 272:923-8. [PMID: 16024347 PMCID: PMC1564088 DOI: 10.1098/rspb.2004.3038] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Maternal and physical factors play a significant role in animal life-history variability, which means that large scale climate change has the potential to affect the size and dynamics of animal populations indirectly through maternal investment and directly through conditions that animals are exposed to. However, little is known about the effects of large-scale oceanographic events such as the El-Niño southern oscillation (ENSO) that influence productivity in the Southern Ocean and the abundance, quality and distribution of prey. The possible mechanisms by which physical factors and primary productivity could influence life-history traits, such as survival of apex predators, includes direct influences such as food availability and foraging success and indirect influences such as stored maternal investment and resource transfer during lactation. Here, we quantify the relative contribution of maternal investment and climate conditions at remote foraging sites to survival in the first year of life for southern elephant seals. We present evidence linking climate (ENSO) and variations in a key demographic parameter--first-year survival--and demonstrate that survival was highest during ENSO events and that the ability of mothers to store and acquire resources, which is typically related to ocean productivity, is the most important determinant of survival in the first year. This functional link provides valuable insights that can be used to model the responses of the seal populations to climate change scenarios.
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Affiliation(s)
- Clive R McMahon
- Australian Antarctic Division, Channel HWY, Kingston 7050, Tasmania, Australia.
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47
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MCMAHON CLIVER, BESTER MARTHANN, BURTON HARRYR, HINDELL MARKA, BRADSHAW COREYJA. Population status, trends and a re-examination of the hypotheses explaining the recent declines of the southern elephant seal Mirounga leonina. Mamm Rev 2005. [DOI: 10.1111/j.1365-2907.2005.00055.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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48
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49
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Maternal and newborn life-history traits during periods of contrasting population trends: implications for explaining the decline of harbour seals (Phoca vitulina), on Sable Island. J Zool (1987) 2003. [DOI: 10.1017/s0952836903004047] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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50
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Mcmahon CR, Burton HR, Bester MN. A demographic comparison of two southern elephant seal populations. J Anim Ecol 2003. [DOI: 10.1046/j.1365-2656.2003.00685.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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