Favourable ocean currents and the dispersal of leatherback turtle hatchlings

On the dispersal of leatherback turtle hatchlings from Mesoamerican nesting beaches

George L. Shillinger, Emanuele Di Lorenzo, Hao Luo,Steven J. Bograd, Elliott L. Hazen, Helen Bailey and James R. Spotila

Proc. R. Soc. B, Published online before print February 29, 2012, doi: 10.1098/rspb.2011.2348

Very little is known about the early life history of leatherback turtles (Dermochelys coriacea) from hatchling to adulthood. This lack of information has led scientists to call this period as the ‘lost years’.

 Here the researchers investigate leatherback hatchling dispersal from four Mesoamerican nesting beaches using passive tracer experiments within a regional ocean modelling system.

The strong influence of eddy transport and coastal currents were clearly discernible. The researchers say modelled hatchlings from Playa Grande, Costa Rica, were most likely to be entrained and transported offshore by large-scale eddies coincident with the peak leatherback nesting and hatchling emergence period. They go on to add that eddies potentially serve as ‘hatchling highways’, providing a means of rapid offshore transport away from predation and a productive refuge within which newly hatched turtles can develop.

The researchers hypothesize that the most important leatherback nesting beach remaining in the eastern Pacific (Playa Grande) has been evolutionarily selected as an optimal nesting site owing to favourable ocean currents that enhance hatchling survival.