Vertical distribution of water temperature around female green turtles during the internesting period

Abstract

Time-depth-temperature data loggers were used to examine the vertical distribution of water temperature and diving behavior of female green turtles, Chelonia mydas, during the internesting period at Huyong Island in the Andaman Sea. The Andaman Sea of western Thailand experiences two main seasons: the relatively calm dry season from November to April and the stormy rainy season from May to October. The dry season is characterized by a north-easterly dry wind off the Asian continent. In contrast, heavy rain and strong winds characterize the rainy season. The vertical profile of ambient water temperatures showed that a thermocline did not develop in the dry season. In the rainy season, water temperature was stable to about 30 m, suggesting that an ocean surface mixed layer had developed. All turtles dived continuously during the internesting period. Dive depth ranged from 12.25 ± 6.24 m (n = 193) to 20.30 ± 10.95 m (n = 137) in the dry season and was 23.13 ± 16.32 m (n = 777) in the rainy season.