The Effects of Light Pollution on Sea Turtle Nesting

provided by Clinic for the Rehabilitation of Wildlife

Approximately 90 percent of sea turtle nesting in the United States happens on Florida’s beaches, according to the Sea Turtle Conservancy. The most common nests in Southwest Florida are that of the Loggerhead. In a single nesting season, females can lay between 2 and 6 clutches of eggs, each containing anywhere between 65 to 180 eggs. Out of all the eggs laid during nesting season, it is estimated only one in approximately 1,000 hatchlings survive. Once hatched, the infants must navigate their way to the ocean quickly, risking dehydration and predation. If the hatchling successfully makes it into the ocean, they typically swim several miles offshore. From that point, they could be caught in currents and seaweed carrying them for years providing shelter and nutrition before growing large enough to return to nearshore waters.

Many natural threats can emerge during a sea turtle’s life, and they are especially vulnerable in the first years of their life. A new threat emerging, however, is human impact. Factors like light pollution, plastic pollution, and climate change can impact a turtle’s nesting season, the success of the hatchlings, and the future for many dwindling sea turtle populations.
When a sea turtle hatches, it will usually wait until the night to emerge from their nest. This reduces exposure to any daytime predators. Because of this, hatchlings will use the light of the moon to guide them into the ocean. With an increase in residential communities, especially growing popularity to have homes and resorts close to the beach, there is a growing concern that artificial light associated with an increase of urbanization can negatively affect the chances of hatchlings making it to the ocean. These artificial lights can disorient the hatchlings’ route to the sea.

According to a scientific study conducted by Silva et. al., artificial lighting reduced the nesting success of loggerhead turtles by 20 percent. This data shows enforcing light mitigation is essential in attempting to protect the population of sea turtles who nest in Florida.

Climate change can also be a factor in the incubation of the reptile eggs. According to the Temperature-Dependent Sex Determination, or TSD (which applies to many species of reptiles), the temperature at which the eggs incubate determines the sex of the babies. When the eggs are incubated in the sand, cooler sand will yield more male turtles, while warmer sand will yield more females. As global temperatures are on the rise, this could potentially mean more females hatching every year, potentially affecting the genetic diversity of sea turtle species.

To conserve sea turtle populations, be sure to keep lights off after sunset to allow hatchlings to follow only the light of the moon. If you must have lights outdoors, please use red lights. In addition, be cautious when walking on the beach at night and avoid sea turtle nests. Organizations such as SCCF staff and volunteers will create a protective barrier around sea turtle nests to deter predators and humans from going too close. If walking a dog on the beach, always use a leash and please do not allow the pet to approach sea turtle nests.

THIS WEEK AT CROW (4/24-4/28):
There were over 44 new patients admitted to CROW this week, including 2 Anhingas, a Black Vulture, a Brown Pelican, a Black-throated Blue Warbler, a Common Yellowthroat, 2 Double-crested Cormorants, a Limpkin, an Ovenbird, a Red-bellied Woodpecker, a Red-shouldered Hawk, a Rose-breasted Grosbeak, and 6 Virginia Opossums. Recent releases include a Common Gallinule, a Gray Catbird, and a Blue Jay. Check out a full list of CROW’s current patients and recent releases.

Wildlife doesn’t have health insurance! Your donations help cover the costs of medical and rehabilitative care for over 5,000 patients admitted to CROW’s Wildlife Hospital each year.

Want to learn more about wildlife rehabilitation? Stop by CROW’s Visitor Education Center at 3883 Sanibel Captiva Road.

About Clinic for the Rehabilitation of Wildlife (CROW)
Established in 1968, the Clinic for the Rehabilitation of Wildlife (CROW) is a teaching hospital saving the sick, injured and orphaned native and migratory wildlife of Southwest Florida and beyond.  Through state-of-the-art veterinary care, public education programs and an engaging visitor center, CROW works to improve the health of the environment, humans and our animals through wildlife medicine. For more information, or to plan your visit, go to If you find an animal that is in need of help, call (239) 472-3644 ext. #222.

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