Climate influences on female survival in a declining population of southern elephant seals (<i>Mirounga leonina</i>)

Volzke, Sophia; McMahon, Clive R.; Hindell, Mark A.; Burton, Harry R.; Wotherspoon, Simon

doi:10.1002/ece3.7919

Cited by 11 publications

(8 citation statements)

References 76 publications

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“…The Southern Ocean ecosystem relies heavily on phytoplankton and krill abundance for other species' survival, previously reported for Antarctic whales, King Penguins (Aptenodytes patagonicus), and SES (McIntyre et al 2014;Cristofari et al 2018;Bestley et al 2020;Rogers et al 2020;Agrelo et al 2021;Volzke et al 2021). Over the last four decades, the global SES population has seen dramatic declines in some populations due to the changes in food availability (McMahon et al 2005a;Volzke et al 2021). Populations of the four main breeding stocks, South Georgia, Kerguelen Islands and Heard Island, Macquarie Island, and Península Valdés, have all decreased since the 1970s.…”

Section: Population Declines Impacted By Climate Changementioning

confidence: 88%

“…Broad climate events such as El Niño can affect the oceanic structure of the Southern Ocean. The Southern Ocean ecosystem relies heavily on phytoplankton and krill abundance for other species' survival, previously reported for Antarctic whales, King Penguins (Aptenodytes patagonicus), and SES (McIntyre et al 2014;Cristofari et al 2018;Bestley et al 2020;Rogers et al 2020;Agrelo et al 2021;Volzke et al 2021). Over the last four decades, the global SES population has seen dramatic declines in some populations due to the changes in food availability (McMahon et al 2005a;Volzke et al 2021).…”

Section: Population Declines Impacted By Climate Changementioning

confidence: 91%

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Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Chua

McMahon

et al. 2022

Polar Biol

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Marine 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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Section: Population Declines Impacted By Climate Changementioning

confidence: 88%

Section: Population Declines Impacted By Climate Changementioning

confidence: 91%

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Chua

McMahon

et al. 2022

Polar Biol

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“…Branding does not negatively affect survival [35] and produces a lifetime individual mark that is easily read from a safe distance [36]. Until 2001, standardized surveys collected resights of marked individuals (i) daily on the main breeding site of the northern isthmus beaches, (ii) every 10 days on the northern third of the island, and (iii) once a month across the whole island [37]. After that, resights were collected ad hoc through alignment with other projects and population censuses up until 2015.…”

Section: Methodsmentioning

confidence: 99%

“…Macquarie Island southern elephant seal capture–mark–recapture data are openly available in Dryad () [37] and have been previously published in the Australian Antarctic Data Centre [34]. The data and code supporting this article are provided in the electronic supplementary material [61].…”

Section: Data Accessibilitymentioning

confidence: 99%

“…This species represents a model example of a polygynous mating system, which is mediated by sexdependent developmental differences. Recent demographic research into southern elephant seal population dynamics (growth or decline) has concentrated on female survival and reproduction, quantifying important factors such as juvenile survival and fecundity [10][11][12][13]. Males do not contribute to parental care and so do not influence pup survival or recruitment [14].…”

Section: Introductionmentioning

confidence: 99%

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Extreme polygyny results in intersex differences in age-dependent survival of a highly dimorphic marine mammal

et al. 2023

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Developmental differences in vital rates are especially profound in polygamous mating systems. Southern elephant seals ( Mirounga leonina ) are highly dimorphic and extremely polygynous marine mammals. A demographic model, supported by long-term capture–mark–recapture records, investigated the influence of sex and age on survival in this species. The study revealed clear differences between female and male age-dependent survival rates. Overall juvenile survival estimates were stable around 80–85% for both sexes. However, male survival estimates were 5–10% lower than females in the same age classes until 8 years of age. At this point, male survival decreased rapidly to 50% ± 10% while female estimates remained constant at 80% ± 5%. Different energetic requirements could underpin intersex differences in adult survival. However, the species' strong sexual dimorphism diverges during early juvenile development when sex-specific survival rates were less distinct. Maximizing growth is especially advantageous for males, with size being a major determinant of breeding probability. Maturing males may employ a high-risk high-reward foraging strategy to compensate for extensive sexual selection pressures and sex-specific energetic needs. Our findings suggest sex-specific adult survival is a result of in situ ecological interactions and evolutionary specialization associated with being a highly polygynous marine predator.

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Plastic Behaviour Buffers Climate Variability in the Wandering Albatross

Gillies,

Thorley,

Weimerskirch

et al. 2024

Ecology and Evolution

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Climate change has marked effects on global weather patterns and oceanic systems, impacting animal behaviour and fitness in potentially profound ways. Despite this, we lack detailed information about species' responses to climatic variation. Using an 11‐year tracking dataset of over 300 individual birds, we explore the consequences of variation in the southern annular mode (SAM) and southern oscillation index (SOI) for individual behaviour and fitness in wandering albatrosses Diomedea exulans breeding in the Southern Indian Ocean. Our results reveal distinct responses between males and females to climatic variation that align with the impacts of each climatic index on the distinct foraging ranges of each sex. In positive SAM phases, linked to poorer foraging conditions in female ranges and better conditions in male ranges, females exhibited behaviour consistent with reduced foraging success: that is, fewer prey capture attempts and more movement between feeding patches. Males, on the other hand, showed no behavioural change. During positive SOI phases, associated with good foraging conditions in both male and female foraging ranges, both sexes showed evidence of more successful foraging, with birds engaging in more search behaviour, and taking shorter trips with fewer prey capture attempts, together indicating increased food intake per unit time. We found limited evidence for a role of individual variation, as measured through differences in personality, suggesting that plastic responses to climate are sufficiently important so as to obscure inter‐individual variation. Supporting this was the finding that individual breeding success was unaffected by climatic variation, suggesting that plastic foraging behaviour allows albatrosses to mitigate climate impacts and maintain reproductive output.

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Climate influences on female survival in a declining population of southern elephant seals (Mirounga leonina)

Cited by 11 publications

References 76 publications

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Extreme polygyny results in intersex differences in age-dependent survival of a highly dimorphic marine mammal

Plastic Behaviour Buffers Climate Variability in the Wandering Albatross

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