Emergence pattern of the green turtle, chelonia mydas, hatchlings under laboratory and natural conditions

Green Turtle eggs were collected at random from 5 different nests from the Ras Al-Hadd Reserve in Oman. They were incubated 16hr after oviposition at constant temperatures set at 30–31°C for female producers and at 26–27° for male producers. Standard histological procedure of the gonads was performed for sex determination. Despite the constant temperatures set in the incubators, there were differences among the incubated eggs. This is similar to the natural condition, where an asynchronous pattern of emergence is common. Pipping occurs when the eggshell has a slit and hatching is when the head and one flipper are outside the eggshell. Emergence occurs when the hatchling is completely free from the extraembryonic membranes and eggshell. There was no correlation between the pipping-hatching and hatching-emergence intervals in the female, but in males the two intervals were significantly correlated (P<0.01). Hatchling weights were: 28.22 g (±0.83) for females and 25.74 g (±0.58) for males. In both sexes, hatchling weight did not influence the duration of the two intervals. The duration between pipping emergence was significantly (P<0.01) longer in females than in males. Natural and incubator observations showed that the hatchlings remained in the nest after emergence for at least 48hr until the umbilical swelling had subsided before attempting their emergence escape. While the hatchlings remain inside the eggshell after pipping attached to chorioallontoic/amniotic membranes, they are occasionally vulnerable to injury by nesting turtles, micro-organisms or early-emerged hatchlings inside the nest.