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Publication
Foraging behavior of juvenile loggerhead sea turtles in the open ocean: from Lévy exploration to area-restricted search
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Authors
Advisor(s)
Abstract(s)
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.
Description
Keywords
Argos Biologging Caretta caretta Dive histograms Satellite telemetry . Faculdade de Ciências da Vida
Citation
Freitas, C., Caldeira, R., Reis, J., & Dellinger, T. (2018). Foraging behavior of juvenile loggerhead sea turtles in the open ocean: from Lévy exploration to area-restricted search. Marine Ecology Progress Series, 595, 203-215. 10.3354/meps12581
Publisher
Inter Research