ESR 10:191-202 (2009)  -  doi:10.3354/esr00137

Conservation hotspots: implications of intense spatial area use by breeding male and female loggerheads at the Mediterranean’s largest rookery

Gail Schofield1,2,*, Martin K. S. Lilley2, Charles M. Bishop3, Peter Brown4, Kostas A. Katselidis1,5, Panayotis Dimopoulos1, John D. Pantis6, Graeme C. Hays2

1Department of Environmental & Natural Resources Management, University of Ioannina, G. Seferi 2, 30100 Agrinio, Greece
2Department Biological Sciences, Institute of Environmental Sustainability, Swansea University, Singleton Park, Swansea SA2 8PP, UK
3School of Biological Sciences, University of Bangor, Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
4Navsys Ltd., Kirknewton, Edinburgh EH27 8DY, UK
5National Marine Park of Zakynthos, 1 El. Venizelou Street, 29100 Zakynthos, Greece
6Department of Ecology, School of Biology, UP Box 119, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece

ABSTRACT: The implementation of appropriate protection measures for endangered species in protected areas requires knowledge of their fine-scale habitat use. In May and June of 2006 and 2007, we used GPS loggers (some linked to the Argos system) and a conventional Argos transmitter to track male and female loggerhead turtles Caretta caretta in the vicinity of the breeding area of Laganas Bay within the National Marine Park of Zakynthos, Greece. We obtained (1) 9681 useable locations (mean: 1383 locations ind.–1; range: 519 to 2198 locations) from Tracktag GPS loggers attached to 7 females for a mean duration of 34 d (range: 17 to 52 d); (2) 1245 useable locations (mean: 311 locations ind.–1; range: 38 to 1110 locations) from 4 males fitted with Fastloc Argos tags for a mean duration of 29 d (range: 3 to 51 d) and (3) 100 locations from 1 male fitted with a conventional Argos satellite tag tracked for 128 d. GPS data indicated that before the onset of nesting, both males and females primarily used an area within 500 m of the shore along a core 9 km stretch of coastline, where existing protective legislation requires strengthening. Our observations suggest that a 76.7% female-biased operational sex ratio, measured previously from in-water surveys, may represent a realistic sex ratio estimate in the period before nesting starts. In the first month following the onset of nesting, female spatial distribution remained similar, whereas most males departed for distant areas presumably to forage. Our study provides quantitative evidence of the need to improve the management planning and conservation measures to protect sea turtles in a coastal breeding area, and new insights on male turtle migration.

KEY WORDS: Conservation management · Endangered species · Population density · Marine vertebrate · Migratory species · Multiple paternity · Wildlife telemetry

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Cite this article as: Schofield G, Lilley MKS, Bishop CM, Brown P and others (2009) Conservation hotspots: implications of intense spatial area use by breeding male and female loggerheads at the Mediterranean’s largest rookery. Endang Species Res 10:191-202

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