title: Quasi-planktonic behavior of foraging top marine predators.
abstract: 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.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 7159, LOCEAN-IPSL CNRS/UPMC/IRD/MNHN, F-75005, Paris, France.|Univ Paris Diderot Cité, 5 Rue Thomas Mann, 75013 Paris, France.|CSIRO-UTAS Quantitative Marine Science Program, IMAS, Private Bag 129, Hobart, Tasmania 7001, Australia.
authors.forename: Alice
authors.initials: A
authors.lastname: Della Penna
authors.affiliation: Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), UMR CNRS 8197 and INSERM U1024, 46 rue d'Ulm, F-75005 Paris, France.
authors.forename: Silvia
authors.initials: S
authors.lastname: De Monte
authors.affiliation: Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse III (OMP) and IRD, Toulouse, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Kestenare
authors.affiliation: Centre d'Etudes Biologiques de Chizé, 79360 Villiers-en-Bois, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Guinet
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 7159, LOCEAN-IPSL CNRS/UPMC/IRD/MNHN, F-75005, Paris, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: d'Ovidio
mesh_terms: D061725:Accelerometry / Q000379:methods; D000465:Algorithms; D025041:Animal Migration / Q000502:physiology; D000818:Animals; D004242:Diving / Q000502:physiology; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D005843:Geography; D008386:Marine Biology; D008962:Models, Theoretical; D009791:Oceanography / Q000379:methods; D009792:Oceans and Seas; D010933:Plankton / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D017215:Satellite Communications; D046048:Seals, Earless / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D014872:Water Movements