DOI: 10.5061/dryad.tdz08kqb3
title: Data from: The value of satellite tracking across multiple years to identify key areas for conservation

description: While satellite tracking is widely used to identify areas of particular
 conservation importance, whether there is a need to continue tag
 deployments across many years is unclear. We show that the destinations of
 migrating animals from the same breeding population may differ
 significantly across years, and hence we highlight the value of multi-year
 tracking studies. Between 2012 and 2024, we used Fastloc-GPS Argos and
 Iridium tags to track 58 green turtles (Chelonia mydas) from their nesting
 sites in the Chagos Archipelago. If tracking had taken place in a single
 year, the number of countries used as foraging destinations could have
 been hugely underestimated (n = 1 country in 2024 versus 7 countries used
 across years). Overall, 47 % of tracked individuals foraged in the
 Seychelles, which likely hosts hundreds of thousands of foraging turtles
 across age-classes. Further, the importance of foraging in areas beyond
 national jurisdiction (ABNJs) was only revealed by tracking across years.
 Across years 9 % of tracked individuals foraged on the Saya de Malha Bank,
 a remote ABNJ, equating to likely &gt; 1000 adult females and &gt;
 10,000 green turtles using this foraging area. This added information from
 tracking across multiple years likely extends across sea turtle
 populations as well as other taxa.
description: For further details regarding transmitter attachment and data
 filtering, see the Methods section in the associated paper "The value
 of satellite tracking across multiple years to identify key areas for
 conservation," Stokes et al. (2025).
description: ## README file for: # Data from: The value of satellite tracking across
 multiple years to identify key areas for conservation ## Methods
 Fifty-eight green turtles (*Chelonia mydas*) were satellite-tracked
 following nest deposition on Diego Garcia, Chagos Archipelago, to their
 foraging grounds around the Western Indian Ocean. Fifty-five of these were
 tracked using Fastloc-GPS transmitted via the Argos satellite system. One
 further track failed to transmit any Fastloc-GPS positions but had
 sufficient high-quality Argos location data (classes 3, 2, 1) to be
 included. Two were tracked via the Iridium satellite system. The three
 data types are included as three separate files as named below, with the
 ID field indicating each individual turtle. ### List of files: *
 Chagos_green_turtles_2012_2024_FastlocGPS_n55.csv *
 Chagos_green_turtles_2015_Argos_n1.csv *
 Chagos_green_turtles_2023_Iridium_n2.csv ### List of fields: * ID:
 indicates each individual green turtle * YearDeployed: the year in which
 the transmitter was attached following nest deposition on Diego Garcia *
 DateTime: Date and time of each location * Latitude/Longitude: positional
 information for each location uplink * Residual: indicates location
 quality for Fastloc-GPS location data * Satellites: the number of
 satellites used in determining positional information (Satellites minus
 Bad Sats from Argos download) * LocationClass: indicates location quality
 for Argos-only data (classes 3, 2, 1)\ GPSFixAttempt: for Iridium-linked
 data, * ResolvedQFP indicates quick fix positioning technology has
 successfully secured a GPS position at that location