Marine Biology

, Volume 158, Issue 12, pp 2813–2824 | Cite as

Foraging ecology of leatherback sea turtles in the Western North Atlantic determined through multi-tissue stable isotope analyses

  • Kara L. Dodge
  • John M. Logan
  • Molly E. Lutcavage
Original Paper

Abstract

Leatherback turtles, Dermochelys coriacea, are highly migratory, spending most of their lives submerged or offshore where their feeding habits are difficult to observe. In order to elucidate the foraging ecology of leatherbacks off Massachusetts, USA, stable isotope analyses were performed on leatherback tissues and prey collected from 2005 to 2009. Stable isotope ratios of nitrogen and carbon were determined in whole blood, red blood cells, blood plasma, muscle, liver, and skin from adult male, female, and subadult leatherbacks. Isotopic values were analyzed by body size (curved carapace length) and grouped by sex, and groups were tested for dietary differences. Gelatinous zooplankton samples were collected from leatherback foraging grounds using surface dip nets and stratified net tows, and prey contribution to leatherback diet was estimated using a two-isotope Bayesian mixing model. Skin and whole blood δ13C values and red blood cell δ15N values were correlated with body size, while δ13C values of red blood cells, whole blood, and blood plasma differed by sex. Mixing model results suggest that leatherbacks foraging off Massachusetts primarily consume the scyphozoan jellyfishes, Cyanea capillata and Chrysaora quinquecirrha, and ctenophores, while a smaller proportion of their diet comes from holoplanktonic salps and sea butterflies (Cymbuliidae). Our results are consistent with historical observations of leatherback turtles feeding on scyphozoan prey in this region and offer new insight into size- and sex-related differences in leatherback diet.

Notes

Acknowledgments

We are indebted to many people for making this research possible: C. Merigo, C. Innis, A. Myers, M. Dodge, G. Purmont, M. Leach, B. Sharp, S. Landry, M. Murphy, G. Tomasian, N. Fragoso, K. Sampson, R. Smolowitz, K. Hirokawa, J. Casey, S. Leach, J. Wilson, E. Eldredge, M. Dodd, T. Norton, M. Zani, T. Naessig, K. Sutherland, K. Houtler, I. Hanley, and the late J. Vickery and his crew of the R/V Marguerite. Special thanks to P. Wiebe for lending us his MOCNESS and for his expert advice on running it. We thank A. Ouimette and the staff of the UNH Stable Isotope Lab for assistance with isotope analyses. B. Stacy and J. Wyneken kindly provided samples from stranded Florida leatherbacks. The authors acknowledge use of SEATURTLE.ORG’s Maptool program (http://www.seaturtle.org/maptool/). This work was conducted under the authority of the National Marine Fisheries Service Endangered Species Act Section 10 Permit #1557-03 and University of New Hampshire IACUC #060501, and funded by National Oceanic and Atmospheric Administration Grant #NA04NMF4550391 and National Fish and Wildlife Foundation Grant #2008-0076-000 to M. Lutcavage. Turtle disentanglement was conducted under the authority of NOAA 50 CFR Part 222.310 and supported by the Massachusetts Division of Marine Fisheries through the National Oceanic and Atmospheric Administration Grant #NA07NMF4720052. Additional funding was provided by the Cape Cod Commercial Hook Fishermen’s Association. K. D. was supported by a UNH Marine Program Fellowship. We thank H. Haas, J. Houghton, B. Wallace, and one anonymous reviewer for comments that improved earlier drafts of this manuscript.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Kara L. Dodge
    • 1
    • 3
  • John M. Logan
    • 2
  • Molly E. Lutcavage
    • 3
  1. 1.Department of Biological SciencesUniversity of New HampshireDurhamUSA
  2. 2.Massachusetts Division of Marine FisheriesNew BedfordUSA
  3. 3.Large Pelagics Research CenterUniversity of Massachusetts-AmherstGloucesterUSA

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