1. Population Ecology Group; Institut Mediterrani d’ Estudis Avançats; IMEDEA (CSIC-UIB); Miquel Marquès, 21 Esporles 07190 Spain
2. The Leatherback Trust; Goldring-Gund Marine Biology Station; Playa Grande Costa Rica
3. Department of Biology; Indiana-Purdue University; Fort Wayne Indiana 46805 USA
4. Department of Biodiversity, Earth and Environmental Science; Drexel University; Philadelphia Pennsylvania 19104 USA