Foraging behavior of juvenile loggerhead sea turtles in the open ocean: from Lévy exploration to area-restricted search

• Published in: Marine Ecology Progress Series
• Main Authors: Freitas, C., Caldeira, R., Reis, J., Dellinger, T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter Research 2018
• Subjects: Argos; Biologging; Caretta caretta; Dive histograms; Satellite telemetry; Faculdade de Ciências da Vida; North Atlantic
• Online Access: http://hdl.handle.net/10400.13/3381; https://doi.org/10.3354/meps12581

Most sea turtle species spend part of, or their entire juvenile stage in pelagic habitats. A key question is how pelagic turtles exploit their environment to optimize prey intake and max imize fitness. This study combined animal telemetry with remote-sensed environmental data to quantify the drivers and patterns of foraging behavior of juvenile loggerhead sea turtles in the pelagic eastern North Atlantic. Juveniles ranged in size from 34 to 58 cm straight carapace length. First-passage time (FPT) analysis, used to quantify search effort, indicated that turtles performed area-restricted searches at nested spatial scales of 10 and 50 to 200 km. High-usage areas, as quantified by FPT, were associated with increased dive activity and weak surface currents, as well as with oceanographic features (high chlorophyll a and shallower bathymetry) thought to stimu late prey availability. Conversely, low-usage areas (i.e. transit areas) were associated with deep, probably exploratory dives, typical from Lévy movement patterns. Further interpretation of dive data indicates greater dive activity in shallow depths (0 to 10 m) during the night and during tran sit. Conversely, greater activity at intermediate depths (10 to 50 m) was observed during daytime, under strong lunar illumination and in high-usage areas, suggesting these depths are major day time foraging layers. This study clarifies the foraging ecology of sea turtles during their develop ment phase in the open sea, providing evidence that these pelagic predators can adjust their for aging strategies and effort in response to the local conditions of their dynamic environment. info:eu-repo/semantics/publishedVersion