Zakynthos 2007: Loggerhead Turtles

Marine Turtle Research Group

Dataset credit

Data provider
Marine Turtle Research Group
Originating data center
Satellite Tracking and Analysis Tool (STAT)
Project partner
This project is carried out by Judith Zbinden, Brendan Godley and additional members of the Marine Turtle Research Group at the University of Exeter, Cornwall Campus. Fieldwork is carried out in cooperation with ARCHELON, The Sea Turtle Protection Society of Greece. This greek NGO has been monitored turtles and their habitat on Zakynthos since the 1983. The research is approved by the National Marine Park of Zakynthos.

Judith Zbinden is supported by a grant from the Swiss National Science Foundation. Stable isotope analysis will be conducted at the Life Sciences Community Stable Isotope Facility, hosted by the Scottish Universities Environmental Research Centre.

Project sponsor or sponsor description
Satellite tracking is sponsored by three Swiss Foundation: The MAVA - Stifung für Naturschutz continued its involvement with the study population and is founding the majoriy of transmitters. Additional funds are provided by the Basler Stifung fuer biologische Forschung as well as the Karl Mayer Stiftung.


Primary contact Judith Zbinden Marine Turtle Research Group
Data entry Michael Coyne


Zbinden J. 2021. Zakynthos 2007: Loggerhead Turtles. Data downloaded from OBIS-SEAMAP ( on yyyy-mm-dd and originated from Satellite Tracking and Analysis Tool (STAT;


The main aim of this project is to expand on previously conducted satellite tracking (by the University of Bern, Switzerland) to understand migration patterns and foraging area location of the largest loggerhead sea turtle breeding aggregation in the Mediterranean on Zakynthos, Greece. Such knowledge is key to protection of adults away from the breeding area. The area of Zakynthos becoming very well protected in the last years by a national marine park, matching protection of these same individuals at sea is imperative for population health.
Additionally, we aim to further investigate over-wintering behaviour in one of the presumably important foraging areas for the population, the Adriatic Sea. Water temperatures in its northern part drop far below what loggerheads can deal with, and extended over-wintering migrations have been observed in previously tracked individuals. Part of the transmitters we deploy in the current project not only render location information, but will allow to infer to diving patterns.

Beyond satellite tracking, we investiate the suitability of a complimentary method, namely stable isotope analysis, for the study of sea turtle migration. If these chemical compounds differ in the tissue of turtles occupying geographically distinct foraging areas, it should be possible to infer to an individual¢s foraging location from samples obtained at the breeding area. To this aim, different tissues allowing non-intrusive sampling (e.g. commensal barnacle, scute flakes, non-viable eggs) are collected.

The nesting area of Zakynthos comprises six individual nesting beaches (Marathonissi, East Laganas, Kalamaki, Daphni, Sekania and Gerakas) in a small geographical area. ARCHELON tagging data has revealed that most female turtles use different beaches for nesting, both within (Loggerheads lay several clutches during a nesting season, but typically only reproduce every few years) and between seasons.



Supplemental information

Visit STAT's project page for additional information.




This section explains attributes included in the original dataset. OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only. Should you need other attributes described here, you are encouraged to contact the data provider.

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.

Attributes in dataset

Attribute (table column)Description
prognumProgram number
tag_idPTT ID
lcLocation class
iqQuality indicator
dir1Dir 1
nb_mesNumber of messages received
big_nb_mesdefinition not provided
best_levelBest signal strength in dB
pass_durationPass duration in seconds
nopcNumber Of Plausibility Checks successful (from 0-4)
calcul_freqCalculated frequency
altitudeAltitude used for location calculation
speciesSpecies name
project_idSTAT Project ID
lc_filterParameters to location filtering
speed_filterParameters to speed filtering
distance_filterParameters to distance filtering
topo_filterParameters to topo filtering
time_filterParameters to time filtering
angle_filterParameters to angle filtering
life_stageLife stage of the animal
genderGender of the animal
wetdryWet or dry
wetdry_filterParameters to Wet or dry filterint
obs_datetimeDate and time (local time zone)
timezone_hTime difference from UTC
Marine mammals0
Sea turtles3,468
Rays and sharks0
Other species0
Non spatial0
Non species0
Date, Begin2007-07-11
Date, End2009-05-28
Temporal prec.111111
Latitude28.50 - 55.81
Longitude-37.47 - 74.50
Coord. prec.3 decimal digits
Data typeTelemetry location
TracklinesYES (ID: 1904)
Traveled (km)167,816
Travel hours88,316
Contr. throughSatellite Tracking and Analysis Tool
Sharing policy Permission required
Also available in Aggregated summary in
GBIF (via DOI)
See metadata in static HTML
See metadata in FGDC XML
See download history / statistics