Age estimation by phalangeal skeletochronology of Caretta caretta from the Mediterranean Sea

Skeletochronological analysis was performed on Loggerhead sea turtles (Caretta caretta) stranded on the Italian Adriatic and Mediterranean coasts from July 1999 to October 2002. Only the phalanxes of the forelimbs were analysed. The bones were cut at mid-diaphyseal level. After decalcification, they were sectioned by cryostat and stained with Erlich's hematoxylin. Phalanx cross-sections showed well-defined and grossly concentric lines of arrested growth (LAGs). The number of which was correlated with the curved carapax length (CCL). In order to more accurately estimate the individual age, also the number of LAGs lost due to bone resorption was calculated, using osteometric analysis, and added to the number of visible LAGs. Our study showed a longevity ranging from 9 to 18 years for individuals with CCL between 28 and 49 cm; longevity was often greater than 20 years in individuals with CCL over 50 cm. The oldest individual had 83 cm of CCL and was approximately 32-37 years old.