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Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean
journal contribution
posted on 2002-07-01, 00:00 authored by A Broderick, F Glen, B Godley, Graeme HaysGraeme HaysMost species of marine turtle breed every two or more years and it is the norm for females to lay more than one clutch of eggs within a nesting season. Knowing the interval between breeding seasons and the clutch frequency (number of clutches laid by an individual in a breeding season) of females allows us to assess the status of a nesting population. At Alagadi Beach, Northern Cyprus, over a period of 6 years (1995–2000), we attributed 96% of green Chelonia mydas and 80% of loggerhead Caretta caretta turtle clutches to known individual females. This intensive level of monitoring enabled us to estimate the clutch frequency for both species. Using four different methods we estimated clutch frequency to be 2.9–3.1 clutches per female for green turtles and 1.8–2.2 clutches per female for loggerhead turtles. The median interval between nesting seasons for green turtles was 3 years, and for loggerhead turtles it was 2 years. Utilizing these parameters and available data from other beaches that are monitored regularly, we estimate that there are 2,280–2,787 logger-head and 339–360 green turtles nesting annually at these sites in the Mediterranean. This highlights the Critically Endangered status of this population of green turtles. Furthermore, as conventional beach patrols underestimate clutch frequency, these population estimates are likely to be optimistic.
History
Journal
OryxVolume
36Issue
3Pagination
227 - 235Publisher
Cambridge University PressLocation
Cambridge, EnglandPublisher DOI
ISSN
0030-6053Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2002, Cambridge University PressUsage metrics
Keywords
Caretta carettaChelonia mydasclutch frequencyCyprusinter-nestingmarine turtlesMediterraneanre-migrationScience & TechnologyLife Sciences & BiomedicineBiodiversity ConservationEcologyBiodiversity & ConservationEnvironmental Sciences & EcologyCARETTA-CARETTACHELONIA-MYDASPOPULATION-STRUCTUREASCENSION-ISLANDATLANTICSEAREPRODUCTIONDEMOGRAPHYFREQUENCYZoologyEcology
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