In 2006, Gail Schofield initiated a PhD study (Universities of Ioannina, Thessaloniki & Patras and the University of Wales-Swansea in collaboration with the National Marine Park of Zakynthos) to investigate in-water movement of loggerhead sea turtles (Caretta caretta) using GPS technology in the marine area of the National Marine Park of Zakynthos (NMPZ) on Zakynthos island in Greece. The 3 existing marine protection zones were designated prior to the formation of the NMPZ based on nesting beach information. Hence the actual marine area use by the largest loggerhead breeding population in the Mediterranean was unknown.

Female loggerhead sea turtle following TrackTag GPS logger attachment

Understanding movement patterns and the factors that affect animal distribution are integral components of conservation and natural resource management. This is particularly true of the NMPZ marine area where sustainable business endorsement schemes are in development. Due to the required fine-scale nature of the study, we selected to use GPS based technology (retrievable loggers and non-retrievable transmitters) accurate to 10-50m, in place of conventional satellite transmitters with an accuracy of +1km

2006 - FEMALE LOGGERHEAD TRACKING

TrackTag© GPS loggers placed on 3 female loggerheads in May, and retrieved at the end of June, indicated that turtles primarily used a 5km nearshore area in Laganas Bay utilising sea-bed depths of 1-5 metres. These observations, combined with data from a pilot GPS sighting study of sea turtle distribution in 2003, clearly showed that the level of protection provided by the 3 existing marine zones required updating. Hence the NMPZ introduced a designated ‘Ecotourism Zone’ in which only boats endorsed by the NMPZ may enter and operate. While the GPS tracking study provided new insights into female loggerhead movement, we still needed to obtain information about area use by male loggerheads.

click on image to enlarge

Male loggerhead sea turtle following Sirtrack GPS transmitter attachment

2007 - MALE LOGGERHEAD TRACKING

Therefore in 2007 we set out to follow the movements of 5 male loggerhead sea turtles from May onwards to assess

1. Area use in Laganas Bay during the mating period

2. Period of residency

3. Migration out of Laganas Bay to foraging/overwintering grounds in other parts of the Mediterranean

Males were captured using the established 'rodeo' technique, and new "Fastloc™" GPS transmitters were attached to their carapaces. The transmitters do not require retrieval as location data from the animal is stored on board and transmitted via Argos (see preliminary locations below)

PhD RESEARCH SUPERVISORS

• John D. Pantis - Aristotle University of Thessaloniki

• Panayotis Dimopoulos - University of Ioannina

• Graeme C. Hays - Swansea University, Wales

FINANACIAL & LOGISTICAL SUPPORT

• The Peoples Trust for Endangered Species

• The British Chelonia Group

• TrackTag© - Peter Brown

• The Bangor University, Wales - Charles M. Bishop

• The National Marine Park of Zakynthos

• The Swansea University, Wales

Preliminary diagram showing the movement of 4 males with Sirtrack GPS transmitters from May onwards in 2007

2007 In-water turtle capture team

ADDITIONAL ACKNOWLEDGEMENTS

• Sea turtle in-water capture team and boat drivers: Martyn Baker, Kostas Gounelis, Kostas Katselidis, Martin K.S. Lilley, Nikos Margaris,Giorgos Mitrouskas, Mike-Jen-Hannah Sheldon

• Sea turtle in-water & beach retrieval assistants: NMPZ personnel: Sofia Alexiou, Sakis Botos, TyAnn Lee, Ines Palomares, Veneranda Petta-Bika, Enrico Marcon; Archelon volunteers: Mark Barrett, Philip Bradshaw, Chris Dean, Bronwen Gill, Alex Hogg, David Oakely, Emma Ransome, Bianca van Divendyk, Nick Walters, Judith Zbinden

• Special thanks to V. Hobson, L. Sourbes, K. Papadimitriou and D.G. Schofield with GIS assistance and advice