Della Penna A. auteur aut IRD De Monte S. auteur aut IRD Kestenare Elodie auteur aut IRD Guinet C. auteur aut IRD d'Ovidio F. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels. specialized KERGUELEN OCEAN AUSTRAL 036 5 art. 18063 [10 p.] 2015 2045-2322 https://www.documentation.ird.fr/hor/fdi:010065663 10.1038/srep18063 2045-2322 [F B010065663] https://www.documentation.ird.fr/hor/fdi:010065663 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-10/010065663.pdf IRD - Base Horizon / Pleins textes 2016-01-14 2017-10-31 fdi:010065663 fre