LEATHERBACK TURTLE MOVEMENT PATTERNS

Abstract

Eastern Pacific leatherback turtle (Dermochelys coriacea) on the nesting beach in Parque Nacional Las Baulas, Playa Grande, Costa Rica. Leatherback turtle populations have been rapidly declining in the Pacific Ocean, primarily as a result of loss of nesting habitat, poaching of eggs, and bycatch in fisheries. Photograph by Jason Bradley, BradleyPhotographic.com. Western Pacific leatherback turtle departing Jamursba Medi, Indonesia, at Bird’s Head nesting beach at dawn. Leatherbacks return years later to lay their eggs on the beaches where they were born. Photograph by Ricardo F. Tapilatu. Leatherback turtles (Dermochelys coriacea) are critically endangered and have been rapidly declining in the Pacific Ocean. There are two populations in the Pacific, and our study is the first to combine satellite telemetry data from both populations. This resulted in the analysis of 135 individual tracks, the largest leatherback data set ever assembled. We identified distinct migration and foraging patterns. Leatherbacks from the West Pacific migrated to multiple foraging grounds, whereas those from the East Pacific had a more limited distribution in the southeast Pacific. This will affect their vulnerability to being caught in fisheries, a major cause of mortality. Leatherback turtle in a tropical foraging ground off the Kei Kecil Islands, Indonesia. Leatherbacks feed on sea nettle jellyfish that are seasonally present due to wind-driven upwelling from September to December. Photograph by Toppx2. A leatherback turtle coming to the surface to breath on the feeding ground off California, USA. Photograph by Scott Benson. A leatherback turtle is captured off California, USA, so that a satellite tag can be attached. These tags provide the location of the animal and can transmit for over a year. This is a valuable technique for studying leatherbacks, which travel long distances, and has provided vital information for their management and conservation. Photograph by Helen Bailey. A satellite-tagged leatherback turtle off California, USA. The leatherbacks that nest in Indonesia travel across the entire North Pacific Ocean to feed on the dense aggregations of jellyfish that are present in the California Current System during the summer and autumn. Photograph by Scott Hansen. These photographs illustrate the article “Identification of distinct movement patterns in Pacific leatherback turtle populations influenced by ocean conditions,” by Helen Bailey, Scott R. Benson, George L. Shillinger, Steven J. Bograd, Peter H. Dutton, Scott A. Eckert, Stephen J. Morreale, Frank V. Paladino, Tomoharu Eguchi, David G. Foley, Barbara A. Block, Rotney Piedra, Creusa Hitipeuw, Ricardo F. Tapilatu, and James R. Spotila, tentatively scheduled to appear in Ecological Applications in April 2012.