USE OF ISOTOPIC ANALYSIS OF VERTEBRAE IN RECONSTRUCTING ONTOGENETIC FEEDING ECOLOGY IN WHITE SHARKS

Authors

  • James A. Estrada,

    1. Department of Biological Sciences, University of New England, Biddeford, Maine 04004 USA
    Search for more papers by this author
  • Aaron N. Rice,

    1. Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637 USA
    2. Division of Fishes, Department of Zoology, Field Museum of Natural History, Chicago, Illinois 60605 USA
    Search for more papers by this author
  • Lisa J. Natanson,

    1. National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Narragansett, Rhode Island 02882 USA
    Search for more papers by this author
  • Gregory B. Skomal

    1. Massachusetts Division of Marine Fisheries, Martha's Vineyard Research Station, Vineyard Haven, Massachusetts 02568 USA
    Search for more papers by this author

    Abstract

    We conducted stable 13C and 15N analysis on white shark vertebrae and demonstrated that incremental analysis of isotopes along the radius of a vertebral centrum produces a chronological record of dietary information, allowing for reconstruction of an individual's trophic history. Isotopic data showed significant enrichments in 15N with increasing sampling distance from the centrum center, indicating a correlation between body size and trophic level. Additionally, isotopic values verified two distinct ontogenetic trophic shifts in the white shark: one following parturition, marking a dietary switch from yolk to fish; and one at a total length of >341 cm, representing a known diet shift from fish to marine mammals. Retrospective trophic-level reconstruction using vertebral tissue will have broad applications in future studies on the ecology of threatened, endangered, or extinct species to determine life-long feeding patterns, which would be impossible through other methods.

    Ancillary