Annular Growth Layers in Juvenile Loggerhead Turtles (Caretta Caretta)

Juvenile loggerhead turtles (Carella carella) were tagged with tetracycline to establish a chronology for deposition of periosteal bone growth layers. Eight recaptures, encompassing intervals of 1 to 3 years, were used to demonstrate that these growth layers were typically deposited on an annual basis. However, the number of scorable growth layers represents an underestimate of true age because earlier growth layers are obscured by expansion of the medullary cavity during growth. The number of absorbed growth layers was extrapolated from calculations based on juvenile bone growth patterns. Most (83%) of these corrected age estimates for juvenile loggerheads, 40 to 80 cm straight line carapace length, were between 5 and 15 years.