, Volume 157, Issue 2, pp 221–230 | Cite as

Density-dependent effects on hatching success of the olive ridley turtle, Lepidochelys olivacea

  • Shaya Honarvar
  • Michael P. O’Connor
  • James R. Spotila
Population Ecology - Original Paper


Historically, the olive ridley arribada at Playa Nancite, Costa Rica, was one of the largest olive ridley arribadas in the eastern Pacific with 70,000 nesting females in a year. Recently the Nancite arribada drastically declined. We hypothesized that the population decline at Playa Nancite could have been due to low hatching success as a result of the high density of nests on the beach, such that recruitment to the population was insufficient to balance losses. To test this hypothesis, we examined density-dependent effects on hatching success and their underlying mechanisms by experimentally manipulating nest densities in experimental plots on the nesting beach. We set up four nest-density treatments in five experimental blocks. We measured effects of density on hatching success, CO2 and O2 concentrations and temperature both within nests and in sand adjacent to nests frequently during incubation. Experimental nest densities affected hatching success with the highest density having the lowest hatching success. Higher nest density led to lower O2 levels and higher CO2 levels in the nest with greater changes in the latter part of the incubation. Highest temperatures occurred in high-density areas. Temperatures were lower in sand surrounding the nest than in the nest. Effects of density on temperature, CO2 and O2 were confirmed at a naturally high-density nesting beach, Playa La Flor, Nicaragua. Long-term failure in production of hatchlings due to historic high densities may have contributed to the decline of arribadas on Playa Nancite. Thus, density-dependent population control would have operated at the embryonic life stage in this population of olive ridley turtles.


Arribada Carbon dioxide Oxygen Playa La Flor Playa Nancite 



We thank Roger Blanco Segura, Yorlan Diaz Chavarria, Emily Davis, Luis Gabriel Fonseca Lopez, Grettel Murillo Quiros and Luis Araya Sanchez for help in the field. Thanks to Jack Suss, Bryan Wallace, Susan Kilham and Loretta D. Spotila for help in the laboratory and with the manuscript. This research was funded by the Betz Chair of Environmental Science at Drexel University, Koinonia Foundation and The Leatherback Trust. A special thank you to Thomas Elzey for his support of this research. Experiments complied with the current laws of Costa Rica and Nicaragua. Approvals were provided by MINAE in Costa Rica, MARENA in Nicaragua and Drexel University IACUC.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Shaya Honarvar
    • 1
  • Michael P. O’Connor
    • 1
  • James R. Spotila
    • 1
  1. 1.Department of Bioscience and BiotechnologyDrexel UniversityPhiladelphiaUSA

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