Zakynthos 2007: Loggerhead Turtles

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.

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.

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Overview

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
prognum	Program number
tag_id	PTT ID
lc	Location class
iq	Quality indicator
dir1	Dir 1
nb_mes	Number of messages received
big_nb_mes	definition not provided
best_level	Best signal strength in dB
pass_duration	Pass duration in seconds
nopc	Number Of Plausibility Checks successful (from 0-4)
calcul_freq	Calculated frequency
altitude	Altitude used for location calculation
sensors	Sensors
species	Species name
project_id	STAT Project ID
lc_filter	Parameters to location filtering
speed_filter	Parameters to speed filtering
distance_filter	Parameters to distance filtering
topo_filter	Parameters to topo filtering
time_filter	Parameters to time filtering
angle_filter	Parameters to angle filtering
life_stage	Life stage of the animal
gender	Gender of the animal
wetdry	Wet or dry
wetdry_filter	Parameters to Wet or dry filterint
obs_datetime	Date and time (local time zone)
timezone_h	Time difference from UTC