Green Sea Turtles (Chelonia mydas) in Bermuda Exhibit an Ontogenetic Diet Shift despite Overexploitation of Resources in their Developmental Habitat Thesis

(2017). Green Sea Turtles (Chelonia mydas) in Bermuda Exhibit an Ontogenetic Diet Shift despite Overexploitation of Resources in their Developmental Habitat . 10.25148/etd.FIDC001794

thesis or dissertation chair

authors

  • Burgett, Claire Margaret

abstract

  • Green sea turtles in Bermuda are overgrazing the seagrasses on which later life stages are thought to specialize. I hypothesized that larger green turtles in Bermuda would display individual diet specializations during seagrass scarcity. Stable isotope methods were used to determine the diet composition of green sea turtles from the Bermuda Platform as a function of size class and in turtles captured in successive years. Individual turtles had a wide range of diets, however, the variation in diets was driven by differences among size class rather than within the size classes of larger turtles, indicating that green turtles undergo a dietary ontogenetic shift during their residency on the Bermuda Platform and no clear specialization of diets among late-stage individuals. The apparent lack of dietary specialization of larger turtles indicates that older turtles are not diversifying their diets in response to the drastic reductions in seagrass in Bermuda.

publication date

  • March 27, 2017

keywords

  • food web
  • grazing
  • herbivory
  • isotope mixing models
  • recapture
  • resource availability
  • seagrass
  • stable isotopes

Digital Object Identifier (DOI)