The role of secondary acoustic cues in sea-finding by green (Chelonia Mydas), hawksbill (Eretmochelys Imbricata), and leatherback (Dermochelys Coriacea) sea turtles

Abstract

While light and slope cues have been shown to impact sea-finding in hatchling sea turtles, the possible effects of naturally occurring acoustic cues have not been well explored. We monitored the behavior of hatchling leatherback (Dermochelys coriacea), green (Chelonia mydas), and hawksbill (Eretmochelys imbricata) sea turtles, collected from nesting beaches within the St. Croix Sandy Point National Wildlife Refuge, in the presence of recorded beach surf sounds (72.0 dB re: 20 μPa) and simulated moonlight (4000 K, >1 lm). When beach wave sounds were presented alone, leatherbacks, greens, and hawksbills oriented randomly in the arena. Leatherbacks and greens oriented toward the light source when light was presented alone and when light was located at the same (0°), opposite (180°), or 90° locations relative to the speaker. Hawksbills did not exhibit a significant orientation toward light when presented at the same (0°), opposite (180°), or 90° locations relative to the speaker; however, when light was presented alone, they oriented toward the light. These results suggest that beach waves sounds do not have a secondary orientation effect during sea-finding for leatherback and green hatchlings. Additional research is needed to examine the impact of beach waves sounds as a secondary orientation cue for hawksbill hatchlings.