First Satellite Tracks Of South Atlantic Sea Turtle ‘Lost Years’: Seasonal Variation In Trans-Equatorial Movement

Keywords

Caretta caretta; Dispersal; Marine turtle oceanic stage; Ocean currents; Population connectivity; South Atlantic Ocean

Abstract

In the South Atlantic Ocean, few data exist regarding the dispersal of young oceanic sea turtles. We characterized the movements of laboratory-reared yearling loggerhead turtles from Brazilian rookeries using novel telemetry techniques, testing for differences in dispersal during different periods of the sea turtle hatching season that correspond to seasonal changes in ocean currents. Oceanographic drifters deployed alongside satellite-tagged turtles allowed us to explore the mechanisms of dispersal (passive drift or active swimming). Early in the hatching season turtles transited south with strong southward currents. Late in the hatching season, when currents flowed in the opposite direction, turtles uniformly moved northwards across the Equator. However, the movement of individuals differed from what was predicted by surface currents alone. Swimming velocity inferred from track data and an ocean circulation model strongly suggest that turtles’ swimming plays a role in maintaining their position within frontal zones seaward of the continental shelf. The long nesting season of adults and behaviour of posthatchlings exposes young turtles to seasonally varying ocean conditions that lead some individuals further into the South Atlantic and others into the Northern Hemisphere. Such migratory route diversity may ultimately buffer the population against environmental changes or anthropologic threats, fostering population resiliency.

Publication Date

12-6-2017

Publication Title

Proceedings of the Royal Society B: Biological Sciences

Volume

284

Issue

1868

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1098/rspb.2017.1730

Socpus ID

85037628410 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85037628410

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