The negative impact of artificial lighting, or light pollution, poses dangers to both the females as they come ashore the nesting beaches to reproduce, and to the hatchlings once they leave the nest. Sea turtles use subtle visual cues when on the beach in order to know where the water line is. Under natural conditions, these visual cues include the brightness of the horizon, or the reflection of the stars and the moon in the ocean’s surf.
Light sources shining at the horizon of the nesting beach which are stronger then the natural light at the sea will disorient the turtles and prevent them from reaching the sea. The disorientated turtles then become an easy target for predators, or can get lost and die of dehydration and exhaustion.
Nowadays, artificial lighting can be modified and manipulated in such a way that it does not cause major impact on the beach (turtle-friendly lighting), and cause little disorientation of the adult and hatchling sea turtles.