Vol. 62, 2023

(update: 2023.9.22)

The Effect of Light Pollution on the Sea Finding Behavior of Green Turtle Hatchlings on Lanyu Island, Taiwan

¹Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan. *Correspondence: E-mail: b0107@mail.ntou.edu.tw (Cheng)
E-mail: mousebro2021@gmail.com (Yen); eslangrid@gmail.com (Chan)
²Instiute of Marine Biology, Ieotek Corporation, Neihu 114, Taiwan. E-mail: ethan.peng@teotek.com (Peng); jacke.chang@tecotek.com (Chang)

(Received 29 November 2022 / Accepted 24 July 2023 / Published 22 September 2023)
Communicated by Benny K.K. Chan

Nocturnal animals use their vision and acute hearing to adapt to the nighttime environment. Light pollution has become a serious problem for nocturnal animals in coastal areas, especially nesting sea turtles and sea turtle hatchlings. Hatchlings use visual clues to find the ocean. However, when the artificial light is stronger than the natural light, hatchlings become either misoriented, disoriented or both. Due to rapid tourism development on Lanyu Island, new sources of light pollution, especially streetlights, pose a serious threat to sea turtle hatchlings. In this study, we used a portable lamp constructed by Liteon Inc. on a circular area of a turtle nesting beach to see how artificial light sources could affect green turtle hatchlings' sea finding behavior. In the experiments, we tested hatchling behavior under different lamp settings (strong or weak light intensity; white or yellow light; lamp shield installed or not) and moon visibilities (moonlit or moonless). The hatchlings’ crawling tracks and locations at the end of the trials were recorded. Results showed that the light intensity had no effect on hatchling Sea finding behavior. White light had a stronger impact on hatchling sea finding behavior than yellow light. When the lamp shield was installed on moonlit nights, more hatchings were able to find the sea under both white and yellow lights. Thus, it is recommended that light shields be installed on the streetlights of Lanyu Island in order to protect the sea turtle hatchlings effectively.

Key words: Lanyu Island, Green sea turtle hatchling, Artificial lights, Lamp shield, White and yellow lights

Citation: Yen CH, Chan YT, Peng YC, Chang KH, and Cheng IJ. 2023. Citation: The effect of light pollution on the sea finding behavior of green turtle hatchlings on Lanyu Island, Taiwan. Zool Stud 62:47.