https://doi.org/10.82144/a0cb5ba6 https://seamap.env.duke.edu/dataset/994 https://www.gbif.org/dataset/567afc7d-bc80-465a-beed-13dac452a73e https://obis.org/dataset/d69484a6-ce0c-4d64-b2c9-6282cb9dcb94 Paolo Luschi University of Pisa Primary contact pluschi@biologia.unipi.it OBIS-SEAMAP Marine Geospatial Ecology Lab, Duke University

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seamap-contact@duke.edu https://seamap.env.duke.edu distributor Paolo Luschi University of Pisa Primary contact pluschi@biologia.unipi.it owner 2025-07-31 eng Original provider: Paolo Luschi, University of Pisa, Italy; Graeme Hays, Swansea University, UK; and Susanne Akesson, und University, Sweden Dataset credits: Paolo Luschi, University of Pisa, Italy; Graeme Hays, Swansea University, UK; and Susanne Akesson, und University, Sweden Abstract: Previous tagging studies of the movements of green turtles (<i>Chelonia mydas</i>) nesting at Ascension Island have shown that they shuttle between this remote target in the Atlantic Ocean and their feeding grounds on the Brazilian coast, a distance of 2300 km or more. Since knowledge of sea turtle migration routes might allow inferences on the still unknown navigational mechanisms of marine animals, we tracked the postnesting migration of six green turtle females from Ascension Island to Brazil. Five of them reached the proximity of the easternmost stretch of the Brazilian coast, covering 1777-2342 km in 33-47 days. Their courses were impressively similar for the first 1000 km, with three turtles tracked over different dates following indistinguishable paths for the first 300 km. Only the sixth turtle made some relatively short trips in different directions around Ascension. The tracks show that turtles (i) are able to maintain straight courses over long distances in the open sea; (ii) may perform exploratory movements in different directions; (iii) appropriately correct their course during the journey according to external information; and (iv) initially keep the same direction as the west-south-westerly flowing current, possibly guided by chemical cues. Marine Biology Telemetry Tagged animal Radio transmitters Animal movements N/A This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License. https://seamap.env.duke.edu/dataset/994 Oceans -38.165 -12.45 -5.161 -12.763 1997-04-27 1998-08-20 Scientific names are based on the Integrated Taxonomic Information System (ITIS). species Chelonia mydas Green sea turtle Luschi et al. (1998) reconstructed the routes followed by turtles leaving the island for their postnesting migration, to evaluate their navigational performance. This would then allow a re-examination of the hypotheses so far proposed about the navigational system used by these turtles to pinpoint Ascension, assuming that the same mechanisms guide the postnesting migration as well. Results show that Ascension turtles use information picked up en route to adjust their migratory course, and suggest that current-borne cues, probably of a chemical nature, may be involved in this process for at least part of the journey. Papi et al. (2000) reports the results of an experiment aimed to test the geomagnetic hypothesis by applying a magnetic disturbance to Ascension turtles returning to Brazil. If this disturbance were to impair the orientation of the turtles, this interesting hypothesis would receive its first experimental support. However, the results obtained show that magnetic cues are not essential for oceanic navigation by adult turtles migrating to Brazil. notPlanned Paolo Luschi University of Pisa Primary contact pluschi@biologia.unipi.it NA NA NA Paolo Luschi owner NA zd_994 2025-07-31T16:06:03-04:00 dataset Luschi, P. 2013. Ascension Island green turtles migrations. Version 1.0.0. Dataset published in OBIS-SEAMAP. https://doi.org/10.82144/a0cb5ba6. OBIS-SEAMAP Dataset Page UTF-8 Interactive map https://seamap.env.duke.edu/dataset/994 FGDC Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/994/fgdc EML Metadata UTF-8 XML https://seamap.env.duke.edu/dataset/994/eml OBIS-SEAMAP zd_994 zd_994 Luschi, P., G.C. Hays, C. Del Seppia, R. Marsh and F. Papi. 1998. The navigational feats of green sea turtles migrating from Ascension Island investigated by satellite telemetry. Proceedings of the Royal Society: Biological Sciences: 265: 2279-2284.