Incubation temperatures, sex ratio and hatching success of leatherback turtles (Dermochelys coriacea) in two protected hatcheries on the central Mexican coast of the Eastern Tropical Pacific Ocean

Abstract

Incubation temperatures, sex ratio and hatching success of leatherback turtles have received little attention in conservation programs in Mexico. This study was carried out from October 2014 to May 2017 in two enclosed hatchery sites. To determine temperature parameters in the nest chamber environment and their variation during the incubation period, we placed data loggers in the centre of the egg mass in relocated nests. We then buried other data loggers in the sand near the relocated nests, inside and outside the hatchery. A total of 46 nests were examined over three nesting seasons. Mean nest temperature showed no statistical difference between nests in either the San Juan Chacahua hatchery or in the Palmarito hatchery nests. The mean sex ratio based on average temperature during the middle third of incubation duration was 96.3 % skewed to female production. Hatching success in both San Juan Chacahua and Palmarito was high. Our findings support the common pattern of a female–dominated leatherback turtle sex ratio. Furthermore, hatching success rates in the shade–cloth hatchery were higher than those in the natural nests observed in other population.

Keywords

• hatcheries
• secondary beaches
• clutch size
• nests temperatures
• shading net