Artificial light at night on nesting beaches of the green turtle, Chelonia mydas, in the eastern Mediterranean and its possible effect on populations

Artificial light associated with coastal development is becoming one of the major threats to coastal biodiversity. Sea turtles are coastal breeders, and it is well-known that hatchlings tend to move toward lighter objects on the beach, which prevents them from reaching the sea. It is, therefore, essential to identify the impact of artificial light at night (ALAN) on the nesting beaches. Here, we investigated ALAN levels using imagery from satellites at important green turtle (Chelonia mydas) nesting beaches in the Mediterranean. Mean August radiance levels at nesting beaches ranged from 0.00473 nW/cm2sr (Northern Cyprus-South Karpaz Beach) to 14.44 nW/cm2sr (Turkey – Davultepe Beach). Of the thirteen nesting beaches examined, five were below the threshold value of high ALAN effect (>2 nW/cm2sr). A statistically significant increasing trend was detected throughout the years on mean radiance levels in Kazanlı (r = 0.88, p < 0.01), Samandağ (r = 0.91, p < 0.01), Alata (r = 0.89, p < 0.01) and Davultepe (r = 0.88, p < 0.01). Based on possible scenarios of previously published scientific results, present work revealed the negative impact of ALAN which causes the decline of habitat quality on core nesting beaches of green turtles in the Mediterranean.