The effects of nest incubation temperature on embryos and hatchlings of the loggerhead sea turtle: Implications of sex difference for survival rates during early life stages

Abstract

In sea turtles, higher hatch and emergence successes, larger body size of hatchlings, and superior terrestrial and swimming locomotor performances are important to maximize survival rates. Here, the hatch and emergence successes, embryonic mortality rates, hatchling morphology, and terrestrial and swimming locomotor performances of the loggerhead sea turtle (Caretta caretta) from male and female producing nests were investigated. Mortality rates during the early embryonic stage in the male producing nests were significantly lower than those in the female producing nests. The hatchlings from male producing nests showed higher terrestrial locomotor performances than those from female producing nests. Furthermore, while the other factors did not show differences between the two nesting groups, the high incubation temperatures significantly affected the mortality rate of embryos and the swimming performance of hatchlings. The present study indicates that male hatchlings are likely to have higher survival rates than female hatchlings during the critical terrestrial period. In addition, the present study suggests that as global warming proceeds, female-fate embryos and/or female hatchlings are likely to face lower survival rates than males, owing to high mortality rate of embryos and low swimming performance of hatchlings.