What should be done with misdirected hatchlings found on the beach? Any light source producing light that is visible from the beach is likely to cause problems for nesting sea turtles and their hatchlings. Because any visible light from an artificial source can cause problems, the most reliable "instruments" to use when making judgments about problem lighting may be the eyes of a human observer on the nesting beach. The effects of artificial lighting on sea turtles may actually increase as ambient light-levels decrease on darker, moonless nights. Unfortunately, no simple measure of light intensity can reveal whether a light source will be a problem. How bright can a light be without affecting hatchlings or adult sea turtles on the beach? Regardless, chasing sea turtles away from nesting beaches means that important habitat is lost to them therefore, it is not a beneficial conservation strategy. But even if beaches were lighted to the extent that no nesting occurred, hatchlings on adjacent beaches would be harmed. Apparently, the level of artificial lighting necessary to misdirect hatchlings is well below the level necessary to deter nesting. As lighting is reduced, hatchlings emerging on moonlit nights and at locations far from the lighted property will have a better chance of finding the sea.Ĭan hatchlings be protected by increasing the number of lights on a nesting beach in order to prevent turtles from nesting?Īlthough artificial lighting tends to deter sea turtles from nesting, many do nest on lighted beaches. Why should I modify my lights?Īny reduction in the amount of artificial light reaching the nesting beach helps sea turtles. There are other lights near my beachfront property that are visible from the beach. The resulting glare makes the direction of the artificial source appear overwhelmingly bright-so much brighter than the other directions that hatchlings will ignore other visual cues and move toward the artificial light no matter where it is relative to the sea. To a hatchling on a beach, an artificial light source appears bright because it is relatively close by, yet it is not intense enough to brighten the sky and landscape. The apparent brightness and glare of artificial lighting is what often leads hatchlings astray. Hatchlings that crawl toward artificial light sources are following the same instinctive response that leads them seaward on naturally lighted beaches. Why do artificial light sources attract hatchling sea turtles? This sea-finding behavior can take place during any phase and position of the moon, which indicates that hatchlings do not depend on lunar light to lead them seaward. Hatchlings also tend to move away from darkly silhouetted objects associated with the dune profile and vegetation. On a natural beach, the brightest direction is most often the open view of the night sky over, and reflected by, the ocean. Sea turtle hatchlings have an inborn tendency to move in the brightest direction. How do hatchling sea turtles know where the ocean is when they emerge from their nests?
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