Effects of Temperature Changes on Nesting Success of Hawksbill Sea Turtles in the Persian Gulf Islands

Temperature is one of the factors that can affect the survival of sea turtle hatchlings and nest success. As a critically endangered species, Hawksbill sea turtle nests in several Iranian islands. Few studies have so far been conducted on the effect of temperature on nesting success of this species in the Persian Gulf. The objective of this study is to investigate the effects of temperature on the survival of turtle hatchlings in two nesting areas.

The temperature of the sand and the nest was recorded and analyzed using thermochron data loggers for several consecutive years from 2019 to 2021, from the beginning of the nesting season until the emergence of hatchlings. The three criteria of incubation success, mortality, and emergence success were chosen as indicators to evaluate nest success.

The lowest average annual sand temperature was related to Kish Island. The annual average temperature of the nests in Kish and Qeshm Islands showed a significant difference. The Kish nests were at a level higher than the thermal tolerance threshold (33 to 35°C) for less than five days. Examining the success of the nests showed that Kish has a higher than average hatching success than Qeshm, but this result does not hold true for the other two criteria.

Although checking the temperature of the sand and the nest can provide us with useful information regarding the survival of the turtle hatchlings and the implementation of protection decisions, investigating other factors besides temperature can be helpful as well.