Blubber fatty acid profiles indicate dietary resource partitioning juvenile southern between adult and elephant seals

C NEWLAND, Iain Field, P NICHOLS, Corey Bradshaw, M HINDELL

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    When resources are limited or patchy, a species may develop some degree of resource partitioning to reduce intra-specific competition. Development of intra-specific resource partitioning is more pronounced in species with clear phenotypic variation among individuals (e.g. age or sex). Southern elephant seals Mirounga leonina have pronounced sexual dimorphism and range widely in size and foraging range between juvenile and adult stages. However, hypothesized diet-based resource partitioning has been less clear due to difficulties in sampling diet while seals are away from breeding islands. We analysed fatty acids (FAs) from blubber of 122 juvenile seals and compared them to FA profiles from blubber of 52 adult females, and to FA profiles from 51 prey species (grouped as fish and squid) to examine evidence for diet-based resource partitioning in the seals. FA signature analysis revealed physiological and dietary differences between ages. Principle components of the 21 FAs from seal blubber and prey parts distinguished prey from seals, and clearly separated prey species into fish and squid classes. FA profiles from adult females differed to those from juveniles, with the former more 'squid-like' and the latter more 'fish-like'. Variation in FA profiles of seals was also apparent between sexes and during different seasons. Differences in diet between juveniles and adult females suggest resource partitioning occurs in response to large metabolic and physiological differences with age that limit juvenile dispersal and diving abilities. By consuming a different suite of prey species relative to adult females, juvenile southern elephant seals may reduce intra-specific competition.
    Original languageEnglish
    Pages (from-to)303-312
    Number of pages10
    JournalMarine Ecology - Progress Series
    Volume384
    Publication statusPublished - 2009

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    Mirounga
    blubber
    niche partitioning
    elephant
    seals
    fatty acid
    fatty acid composition
    Mirounga leonina
    squid
    diet
    intraspecific competition
    fatty acids
    fish
    gender
    phenotypic variation
    sexual dimorphism
    individual variation
    diving
    foraging
    breeding

    Cite this

    NEWLAND, C ; Field, Iain ; NICHOLS, P ; Bradshaw, Corey ; HINDELL, M. / Blubber fatty acid profiles indicate dietary resource partitioning juvenile southern between adult and elephant seals. In: Marine Ecology - Progress Series. 2009 ; Vol. 384. pp. 303-312.
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    abstract = "When resources are limited or patchy, a species may develop some degree of resource partitioning to reduce intra-specific competition. Development of intra-specific resource partitioning is more pronounced in species with clear phenotypic variation among individuals (e.g. age or sex). Southern elephant seals Mirounga leonina have pronounced sexual dimorphism and range widely in size and foraging range between juvenile and adult stages. However, hypothesized diet-based resource partitioning has been less clear due to difficulties in sampling diet while seals are away from breeding islands. We analysed fatty acids (FAs) from blubber of 122 juvenile seals and compared them to FA profiles from blubber of 52 adult females, and to FA profiles from 51 prey species (grouped as fish and squid) to examine evidence for diet-based resource partitioning in the seals. FA signature analysis revealed physiological and dietary differences between ages. Principle components of the 21 FAs from seal blubber and prey parts distinguished prey from seals, and clearly separated prey species into fish and squid classes. FA profiles from adult females differed to those from juveniles, with the former more 'squid-like' and the latter more 'fish-like'. Variation in FA profiles of seals was also apparent between sexes and during different seasons. Differences in diet between juveniles and adult females suggest resource partitioning occurs in response to large metabolic and physiological differences with age that limit juvenile dispersal and diving abilities. By consuming a different suite of prey species relative to adult females, juvenile southern elephant seals may reduce intra-specific competition.",
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    Blubber fatty acid profiles indicate dietary resource partitioning juvenile southern between adult and elephant seals. / NEWLAND, C; Field, Iain; NICHOLS, P; Bradshaw, Corey; HINDELL, M.

    In: Marine Ecology - Progress Series, Vol. 384, 2009, p. 303-312.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Blubber fatty acid profiles indicate dietary resource partitioning juvenile southern between adult and elephant seals

    AU - NEWLAND, C

    AU - Field, Iain

    AU - NICHOLS, P

    AU - Bradshaw, Corey

    AU - HINDELL, M

    PY - 2009

    Y1 - 2009

    N2 - When resources are limited or patchy, a species may develop some degree of resource partitioning to reduce intra-specific competition. Development of intra-specific resource partitioning is more pronounced in species with clear phenotypic variation among individuals (e.g. age or sex). Southern elephant seals Mirounga leonina have pronounced sexual dimorphism and range widely in size and foraging range between juvenile and adult stages. However, hypothesized diet-based resource partitioning has been less clear due to difficulties in sampling diet while seals are away from breeding islands. We analysed fatty acids (FAs) from blubber of 122 juvenile seals and compared them to FA profiles from blubber of 52 adult females, and to FA profiles from 51 prey species (grouped as fish and squid) to examine evidence for diet-based resource partitioning in the seals. FA signature analysis revealed physiological and dietary differences between ages. Principle components of the 21 FAs from seal blubber and prey parts distinguished prey from seals, and clearly separated prey species into fish and squid classes. FA profiles from adult females differed to those from juveniles, with the former more 'squid-like' and the latter more 'fish-like'. Variation in FA profiles of seals was also apparent between sexes and during different seasons. Differences in diet between juveniles and adult females suggest resource partitioning occurs in response to large metabolic and physiological differences with age that limit juvenile dispersal and diving abilities. By consuming a different suite of prey species relative to adult females, juvenile southern elephant seals may reduce intra-specific competition.

    AB - When resources are limited or patchy, a species may develop some degree of resource partitioning to reduce intra-specific competition. Development of intra-specific resource partitioning is more pronounced in species with clear phenotypic variation among individuals (e.g. age or sex). Southern elephant seals Mirounga leonina have pronounced sexual dimorphism and range widely in size and foraging range between juvenile and adult stages. However, hypothesized diet-based resource partitioning has been less clear due to difficulties in sampling diet while seals are away from breeding islands. We analysed fatty acids (FAs) from blubber of 122 juvenile seals and compared them to FA profiles from blubber of 52 adult females, and to FA profiles from 51 prey species (grouped as fish and squid) to examine evidence for diet-based resource partitioning in the seals. FA signature analysis revealed physiological and dietary differences between ages. Principle components of the 21 FAs from seal blubber and prey parts distinguished prey from seals, and clearly separated prey species into fish and squid classes. FA profiles from adult females differed to those from juveniles, with the former more 'squid-like' and the latter more 'fish-like'. Variation in FA profiles of seals was also apparent between sexes and during different seasons. Differences in diet between juveniles and adult females suggest resource partitioning occurs in response to large metabolic and physiological differences with age that limit juvenile dispersal and diving abilities. By consuming a different suite of prey species relative to adult females, juvenile southern elephant seals may reduce intra-specific competition.

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    KW - diet

    KW - diving behavior

    KW - fat reserve

    KW - fatty acid

    KW - feeding ground

    KW - juvenile

    KW - niche partitioning

    KW - patchiness

    KW - phenotype

    KW - pinniped

    KW - sexual dimorphism

    KW - Cephalopoda

    KW - Mirounga leonina

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    EP - 312

    JO - Marine Ecology - Progress Series

    JF - Marine Ecology - Progress Series

    SN - 0171-8630

    ER -