Abstract

Growth rates can be used as an indicator of overall turtle population health and provide a baseline against which to compare the quality of, or changes in, the conditions in foraging habitats. Previous studies of Green Turtles (Chelonia mydas) in the waters of the Galapagos Archipelago in the late 1970s revealed some of the slowest growth rates ever reported for immature Green Turtles. In this study, we evaluate whether growth rates have changed since the earlier study and the effects of color morph, body size, recapture interval, year, and site of capture on growth rates for Green Turtles at four key foraging grounds in the Galapagos Islands between 2003 and 2008. Results of this study confirm that somatic growth in Galapagos Green Turtles is very slow. In addition, somatic growth is significantly affected by morph, body size, and spatial variation. Mean growth rates generate implausibly long estimates of 133-200 yr for Galapagos Green Turtles to grow from 40-cm straight carapace length to sexual maturity. We also present some data for growth in Hawksbills (Eretmochelys imbricata), representing the first information of growth rates for Hawksbills in the Archipelago.