Sixteen Year (2002-2017) Record of Sea Turtle Strandings on Samandag Beach, the Eastern Mediterranean Coast of Turkey

Abstract

Data on stranded sea turtles allow us to obtain information about age classes, temporal and spatial distributions, and mortality rates in turtles. This study aims to investigate life stages, temporal variation in the number of stranded, body size trend, causes of stranding, and scute deviation of stranded sea turtles on Samandag Beach, the eastern Mediterranean coast of Turkey during 2002-2017. A total of 302 stranded dead turtles were found. Among these, 167 (55.4%) of them were Chelonia mydas, 127 (42%) Caretta caretta, 2 (0.6%) Trionyx triunguis, and 6 individuals (2%) were unidentified. The mean annual stranding values over the years were 10.5 (ranging from 6 to 22) and 7.9 individuals (ranging from 4 to 21) for C. mydas and C. caretta, respectively. Although the adult green turtles were less stranded, sub-adult and adult stages of the loggerhead turtles were intensively stranded. As the body size of the stranded green turtle has slightly increased, the number of stranded green turtles has decreased over the years. Stranding of loggerhead turtles showed no trend in frequency or body size. The causes of death showed significant differences between the two species as well as among the years. Fishing activities and marine pollution is the main cause of strandings on Samandag Beach. Oceanic and sub-adult stage individuals were stranded in especially high numbers due to plastic materials. Adult stages in both sea turtle have less carapacial scute deviation. The present study contributes to the stranded data for both sea turtle species in the Mediterranean. Natal origins of the stranded sea turtles on Samandag Beach should be investigated and a stranding network system should be urgently established.