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Marine Biology

, Volume 144, Issue 4, pp 799–805 | Cite as

Origins of green turtle (Chelonia mydas) feeding aggregations around Barbados, West Indies

  • K. Luke
  • J. A. Horrocks
  • R. A. LeRoux
  • P. H. DuttonEmail author
Research Article

Abstract

Although green turtles (Chelonia mydas Linnaeus) do not nest in Barbados, the easternmost island in the Caribbean archipelago, juveniles are regularly seen foraging in nearshore waters. To examine the stock composition of this foraging population, mitochondrial (mt) DNA control region sequences were analysed from 60 juvenile (31–70 cm curved carapace length) green turtles and compared with data published for key nesting populations in the Atlantic, as well as other feeding grounds (FGs) in the Caribbean. Eight distinct haplotypes were recognised among the 60 individual green turtles sampled around Barbados. Three of the haplotypes found have only previously been reported from western Caribbean nesting beaches, and two only from South Atlantic beaches. The nesting beach origin of one of the Barbados FG haplotypes is as yet unidentified. Stock mixture analysis based on Bayesian methods showed that the Barbados FG population is a genetically mixed stock consisting of approximately equal contributions from nesting beaches in Ascension Island (25.0%), Aves Island/Surinam (23.0%), Costa Rica (19.0%), and Florida (18.5%), with a lesser but significant contribution from Mexico (10.3%). Linear regression analysis indicated no significant effects of rookery population size or distance of the rookery from the FG on estimated contributions from the source rookeries to the Barbados FG. Our data suggest that the similar-sized green turtles sampled on the Barbados FG are a mixed stock of more diverse origins than any previously sampled feeding aggregations in the Caribbean region. The relatively large contribution from the Ascension Island rookery to the Barbados FG indicates that hatchlings from distant rookeries outside the Caribbean basin enter the North Atlantic gyre and become a significant part of the pool from which eastern Caribbean foraging populations are derived. These data support a life cycle model that incorporates a tendency of immatures to migrate from their initial foraging grounds at settlement towards suitable foraging grounds closer to their natal rookeries as they mature.

Keywords

Markov Chain Monte Carlo Green Turtle Markov Chain Monte Carlo Method Feed Ground Nest Beach 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

We thank Stanton Thomas, Fred Watson, and Michael Armstrong for assistance in obtaining the tissue samples. Financial support from George Balazs, the National Marine Fisheries Service (NMFS), and the University of the West Indies to K. Luke are gratefully acknowledged. Thanks to A. Abreu-Grobois for stimulating interest in Atlantic current patterns. Genetic analysis was funded by the NMFS. Samples were obtained under CITES permit numbers 99US786600/9 and 00US844694/9. All work complies with current laws of Barbados and the United States.

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • K. Luke
    • 1
  • J. A. Horrocks
    • 1
  • R. A. LeRoux
    • 2
  • P. H. Dutton
    • 2
    Email author
  1. 1.Department of Biological and Chemical SciencesUniversity of the West IndiesSt. MichaelBarbados
  2. 2.NOAA-FisheriesLa JollaUSA

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