Population decline of loggerhead turtles: Two potential scenarios for Fethiye Beach, Turkey

Abstract

Based on nesting data over a 12-year period (1993-2004), this study points to a negative population trend of the loggerhead turtle population at Fethiye beach, Turkey. The number of nests fluctuated from a maximum of 186 in 1995 to a minimum of 58 in 2004. Successively smaller peaks at 3-year intervals were followed by successively smaller troughs. Two analyses-one representing a dampened oscillation, the other retaining the period and the amplitudes of the nesting cycles-predict that nest number will drop to about 40-50 by 2015, i.e. to about 22-27% of its highest value. This drop at Fethiye does not correspond with a visible increase at neighboring beaches, leading to the interpretation that the number of nesting turtles here is declining. Moreover, the carapace size of emerging adult females is apparently decreasing, as are clutch sizes. Such a potential negative trend at a key Turkish nesting beach is cause for concern, an incentive for continued study, and a call for more coordinated and effective conservation programs in this region of the Mediterranean. © 2006 Springer Science+Business Media B.V.