Reinhold, L., Limpus, C.J., Limpus, D.J. & Whiting, A.U. 2017. Pivotal temperature of Loggerhead sea turtles, Caretta caretta, from Dirk Hartog Island, Western Australia. Memoirs of the Queensland Museum - Nature 60: 161–171. https://doi.org/10.17082/j.2204-1478.60.2017.2016-09
15 June 2017
13 November 2017
Loggerhead sea turtle, Caretta caretta, Western Australia, pivotal temperature, temperature-dependent, sex determination
Investigating responses to different thermal conditions is important for understanding species with temperature-dependent sex determination, including loggerhead sea turtles. We determined the pivotal temperature for loggerhead turtles from Dirk Hartog Island, Western Australia, using constant temperatures in laboratory incubators. Eggs were transported from Dirk Hartog Island, Western Australia to Mon Repos, Queensland, at low temperatures to delay development and minimise movement induced mortality. The pivotal temperature for the Dirk Hartog Island loggerhead sea turtle rookery, is calculated to be 28.7 ± 0.4 °C (SD). The temperature is similar to the eastern Australian population of loggerheads, at the cooler end of a conservative global range. Incubators from 26.4 to 30.1 °C produced both male and female hatchlings, a range also consistent with eastern Australian loggerheads. Incubation periods ranged from 48 days at 31.6 °C to 77 days at 26.4 °C. The pivotal incubation duration to hatching is 63.3 ± 1.2 days (SD). This research indicates Dirk Hartog Island may be a predominantly male producing rookery with lower quantities of females expected.