LASER SAFETY THRESHOLDS FOR CETACEANS AND PINNIPEDS

An increase in the use of oceanographic lidar has raised concern over laser safety for marine mammals. We were able to address some of these concerns by combining information about current laser safety standards, retinal damage mechanisms for humans, and research on eye anatomy for humans, cetaceans, and pinnipeds. To estimate the irradiance at the retina, the image size at the retina and pupil diameter must be known. We estimate the smallest spot size using retinal resolution or visual acuity for six species of cetaceans and five species of pinnipeds. A sensitivity ratio was calculated for each species using the ratio of the irradiance at the retina of the marine mammal to the irradiance at the retina of humans. The sensitivity ratio was used to suggest exposure limits for the various species. Because the human eye is more sensitive than either the cetacean or pinniped eye, we conclude that laser energies that are eye-safe for humans will also be safe for marine mammals, and higher laser irradiances may be permissible if illumination of humans is avoided.