INFLUENCES OF ARTIFICIAL LIGHTING ON THE SEAWARD ORIENTATION OF HATCHLING LOGGERHEAD TURTLES CARETTA-CARETTA

The seaward orientation behavior of hatchling loggerhead turtles Caretta caretta when exposed to five different artificial light sources (high-pressure and low-pressure sodium vapor, and yellow, red, and white incandescent lamps) was examined. Each light source affected hatchling sea-finding performance either in direction of orientation or width of dispersion. Hatchlings were attracted to light sources emitting short-wavelength visible light and long-wavelength sources that excluded intermediate wavelengths. A negative response was observed toward sources emitting predominately yellow light. For this reason, low-pressure sodium vapor (LPS) luminaires, which emit only yellow light, are expected to affect loggerhead hatchling seafinding minimally, if positioned behind the primary dune. LPS luminaires positioned between emerging hatchlings and the ocean, however, will disrupt hatchling orientation.