Sea Turtle Disorientations
Disorientations and Hazards to Sea Turtles
What are disorientations?
Disorientation events occur when artificial lighting on sea turtle nesting beaches disrupts the ability of nesting females and hatchlings to find the sea from the beach. Adult and hatchling sea turtles have an inborn tendency to move in the brightest direction, instinctively crawling away from the dark silhouettes of landward dunes and vegetation towards the brighter open horizon of the ocean.
Artificial lights near the beach are often brighter than the ocean horizon, leading adult females and hatchlings to disorient, or crawl in the wrong direction. Disorientations from artificial lighting are a significant sea turtle conservation problem in Florida.
Each year, nesting females and thousands of nests are impacted by light from beachfront development along Florida’s beaches. Beachfront lighting interferes with sea turtle reproduction by reducing the availability of suitable dark nesting habitat. Both adult females and hatchlings can be disoriented landward by artificial lighting as they attempt to leave the beach after nesting or hatching. Many local governments have adopted beachfront lighting ordinances to address this impact, but accurate, updated information on specific lighting impacts is needed for timely enforcement of these ordinances.
Adult Nesting Female Hazards
Nesting female sea turtles can be impacted by artificial lighting when choosing a nesting site or when returning to the sea. When choosing a nesting site, females may be deterred from areas that are too bright, which can cause them to select a less suitable location to lay their nests. If they do choose a beach with artificial lighting, they may abandon their nesting attempt, which results in a false crawl.
They can also become disoriented after they have nested and are attempting to return to the ocean. They often travel hundreds of yards in the wrong direction, ending up in parking lots, swimming pools, and on busy thoroughfares.
When hatchlings emerge from their nests at night, they rely on vision to help them find the water by distinguishing relative patterns of light and dark. Disorientation events are very harmful to hatchlings because the extra time spent crawling in the wrong direction depletes their small store of energy. Disoriented hatchlings are subject to dehydration, exhaustion, and predation by various beach-dwelling predators, all of which can be fatal.
Sometimes hatchlings crawl into the road where they are run over by cars. Even if disoriented hatchlings eventually reach the water, they may not have enough energy to avoid predators in the sea or for the long swim offshore . These events result in thousands of hatchling deaths each year.