Managing artificial lighting is an important aspect of sea turtle conservation and beach management. Sea turtles instinctually use lighting cues to orient themselves on the beach. These behaviors hold true whether it is a female looking for a suitable nesting site or a newly-emerged hatchling attempting to find the ocean for the first time.
Research has proven that certain lights, wavelengths and lumens can cause sea turtles to become misoriented (i.e., maintaining constant directional movement in any direction other than toward the ocean; Figure 1) or disoriented (i.e., unable to maintain a constant directional movement, including frequent changes in direction or circling; Figure 2). Fortunately, there are steps that can be taken to reduce harmful lighting without compromising human safety and security.
A first step in becoming “turtle-friendly” is to change your white bulbs to red ones or those of an appropriate wavelength. Research has shown that sea turtles exhibit the greatest degree of indifference to red lights that emit wavelengths of approximately 650 nm in length. Figure 3 shows this indifference in four species of sea turtles.
In addition to changing bulbs, using turtle-friendly fixtures will help reduce the potential for turtle disorientation. Fixtures with recessed bulbs reduce the amount of light pollution. Adding shields will further reduce the amount of light lost to the atmosphere and will direct light in the appropriate direction. Shields should always cover 180° on the side facing the ocean.
In general, the best policy is to use as few lights as possible, a strategy that reduces both wildlife impacts and energy bills. It is important to remember that light dispersion can also result from exterior and interior lighting. The latter is easily fixed by reducing the number of interior lights that are turned on and by drawing blinds/curtains to reduce filtration to the beach during sea turtle season (May-October). Interior light emission can also be reduced by installing appropriate types of window tinting.
Jekyll Island has an approved and enforced Beach Lighting Ordinance that has been amended and adopted as of August 11, 2008 to include the latest research in regards to lights and sea turtles. To access this ordinance, click here.
The Jekyll Island Authority/GSTC staff and AmeriCorps Patrol Members provide educational materials and serve as a resource for people on the beach while conducting the Saturation Tagging Program. The Patrol Team also conducts monthly lighting surveys on Jekyll’s shoreline in order to identify areas where lighting regimes pose hazards to beach wildlife. Our staff works to educate local residents, hotels, and businesses about turtle-friendly light alternatives and to encourage the implementation and enforcement of our local lighting ordinance.
*All photos and graphs courtesy of Florida Fish and Wildlife Conservation Commission (FWCC).
Check out these links to recommended vendors with approved ‘Turtle-Friendly Lights’: