School of Earth, Environmental, & Marine Sciences Faculty Publications

Document Type

Article

Publication Date

12-1-2026

Abstract

The survival of sea turtle hatchlings on nesting beaches is strongly influenced by anthropogenic factors, particularly light pollution. Artificial light disrupts hatchlings’ natural orientation, as they instinctively seek the brightest point on the horizon to reach the ocean. In March 2023, the Costa Rican Electricity Institute installed 71 red-light lamps in Tortuguero to reduce light-induced disorientation in Chelonia mydas hatchlings. This study assessed the impact of artificial lighting on hatchling orientation along a public beach in Tortuguero, Costa Rica. Using standardized circular arena experiments, we simulated emergence events and analyzed hatchling movement under white and red light conditions during different lunar phases. The V test confirmed that the orientation was significantly clustered toward the seaward direction, with 15 % of hatchlings under white light disoriented toward artificial sources compared to only 5 % under red light. The Watson U2 test further demonstrated significant differences between orientation distributions under white and red light (U2 = 11.86, P < 0.001). Overall, hatchlings exposed to white light showed pronounced disorientation, while those under red light retained a stronger preference for the ocean. These findings highlight the detrimental effects of artificial white light and underscore the value of red-light systems as an effective mitigation strategy for sea turtle conservation and coastal lighting management in critical nesting habitats.

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Publication Title

Journal for Nature Conservation

DOI

10.1016/j.jnc.2026.127409

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