effects of filtered high-pressure sodium lighting on hatchling loggerhead (Caretta caretta L.) and green turtle ( Chelonia mydas L.) hatchlings

Hatchling sea turtles use visual cues to orient to the water. Streetlights placed on coastal roadways can attract the turtles inland. Filters were designed to be used with coastal roadway lighting to eliminate the more harmful wavelengths of light. I tested the General Electric 2422 and NLW filters in a laboratory setting with hatchling loggerhead and green turtles. Both species of turtles were attracted to the amber filtered lighting in arena experiments. Loggerhead hatchlings were used in T-maze experiments where they were given a choice between amber filtered and unfiltered lighting. The turtles preferred the unfiltered lighting to the filtered lighting, even when it was 100 to 1000 times dimmer. I conclude that amber filtered lighting does afford some protection to sea turtles, although it must be used in conjunction with other light management techniques to prevent the disruption of hatchling turtle orientation.