Age determination of long - lived reptiles : some techniques for seaturtles ( * )

The time between a seaturtle's entry into the sea and its return to a nesting beach as an adult, the « Lost Year », has been variously estimated, often speculatively so, with very little data. Age estimates have been based frequently on the rapid growth rate of hatcUing turtles raised in captivity, commonly yielding time estimates from hatching to sexual maturity of less than ten years (e.g.. MARQUEZ, 1972 ; WiTZELL, 1980). Recently, recapture data for juvenile seaturtles have shown that growth rates are geographically variable and very slow in some populations (e.g., Chelonia mydas in the Hawaiian chain; BALAZS, 1982). Because there are only a few seaturtle research programs that are long term and that are sampling juveniles regularly, estimates of growth from recapture data are sparse. Skeletochronology offers a methodology for estimating ages and calculating growth rates without the investment of time necessary for a mark-recapture study. My research in skeletochronology has emphasized seaturtles, the principal goal being the determination of the average age of sexual maturity for different populations and species. This research has encountered problems and solutions that are common to all skeletochronological research and ones that are specific to seaturtles. In the following discussion, I will examine a few of these problems and solutions. PROBLEMS AND SOLUTIONS