Influence of lunar phases and oceanographic parameters on green turtle nesting in Rocas Atoll

Abstract

Animals can synchronize their reproductive behavior patterns with biological rhythms and environmental conditions. Understanding these patterns is particularly critical for conserving endangered species like sea turtles. This study analyzed the relationship between the nesting behavior of the green turtle (Chelonia mydas) and lunar luminosity, lunar phases, and sea surface temperature (SST) in the Atol das Rocas Biological Reserve, Brazil. Field data were obtained through nightly monitoring during the breeding seasons from 2018 to 2020. Although lunar luminosity and lunar phases did not exhibit a statistically significant effect, the highest number of nesting occurrences was observed during the full moon and new moon, which may be related to the spring tide. The SST was the only variable showing a statistically significant relationship with complete oviposition, incomplete oviposition, and false crawl occurrences, indicating the preference of turtles to come ashore at higher temperatures (around 29.5 °C). Furthermore, while lunar luminosity and lunar phases may have some influence on the nesting pattern of the green turtle, they do not limit it, as turtles come ashore under different observed environmental conditions.