Estimates of age and growth in a population of green sea turtles (Chelonia mydas) from the Indian River lagoon system, Florida: a skeletochronological analysis

• Published in: Canadian journal of zoology Vol. 76; no. 8; pp. 1497 - 1506
• Main Authors: Zug, George R, Glor, Richard E
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.08.1998
• ISSN: 0008-4301; 1480-3283
• DOI: 10.1139/z98-090

The Indian River lagoon system harbors a dynamic population of juvenile green sea turtles (Chelonia mydas). This foraging or developmental population occupies the lagoon year-round and periodically experiences cold-stunning events that kill a portion of the population. A sample of 59 C. mydas (28-74 cm straight carapace length) from the December 1989 cold-stunning event was aged by skeletochronology, yielding age estimates of 3-14 years. Mean growth-rate estimates range from 30 to 52 mm/year for most age and size classes, with means for the 6- to 11-year age classes (44-49 mm/year) not significantly different but greater than those of the youngest and oldest classes (3-5 and 12 years old, respectively) (32-38 mm/year). Because of the lack of adults and near-adults in the sample, growth models (e.g., Gompertz) do not yield biologically realistic asymptotes, hence they do not provide accurate estimates of age at sexual maturity. The age estimates suggest that the western Atlantic C. mydas change from a pelagic to a neritic life predominantly as 5- to 6-year-olds and, in central Florida, juveniles may live in a developmental habitat for 6 or more years.