Information About Sea Turtles: Threats from Artificial Lighting

The Problem: Nesting turtles once had no trouble finding a quiet, dark beach on which to nest, but now they must compete with tourists, businesses and coastal residents for use of sandy beaches. U.S. beaches, popular with humans and turtles alike, are now lined with seaside condominiums, houses and hotels. Lights from these developments discourage females from nesting. If a female fails to nest after multiple false crawls, she will resort to less-than-optimal nesting spots or deposit her eggs in the ocean. In either case, the survival outlook for hatchlings is slim.

Lighting near the shore also can cause hatchlings to become disoriented and wander inland, where they often die of dehydration or predation. Hatchlings, scientists believe, have an innate instinct that leads them in the brightest direction, which is normally moonlight reflecting off of the ocean. Excess lighting from the nearshore buildings and streets draw hatchlings toward land, where they may be eaten, run over, or drown swimming pools. While it might seem like a difficult problem to tackle, an estimated one third of all lighting in the U.S. is wasted. With an annual expenditure of about 30 million barrels of oil and 2 million tons of coal on unnecessary lights, the cost of the wasted lighting equals about $2 billion each year!

Species Affected: All species of sea turtles are affected.

The Solution: Reducing the amount of artificial light that is visible from nesting beaches is the first step to reducing light pollution that affects sea turtles. Coastal communities around the world have passed ordinances that require residents turn off beachfront lights during turtle nesting season. Unfortunately, these ordinances are not always enforced and don’t address the larger problem of sky glow that occurs near cities.

Turn off lights visible on nesting beaches or use special fixtures to shield the lights from the beach;

Use low-pressure sodium-vapor lighting (LPS) instead of normal lights;

Use Turtle Safe Lighting – these red lights emit a very narrow portion of the visible light spectrum, which is less intrusive to nesting sea turtles and hatchlings;

If disoriented hatchlings are found away from the sea, call local law enforcement;

Tint windows that face the beach;

Close opaque curtains or blinds after dark to cover windows visible from the beach.

Case Studies: The Sea Turtle Conservancy (STC) is implementing a bold new program to address a problem that kills thousands of sea turtles every year in Florida – artificial lighting that disorients newborn hatchlings trying to find their way to the sea. Considering that about 90% of all sea turtle nesting in the United States takes place on Florida beaches, the loss of hatchlings caused by poorly managed light represents a major obstacle to the recovery of U.S. turtle populations. To date, STC has worked with over 161 properties, representing over 21 miles of beach darkened.

At Gulf Islands National Seashore, approximately half the nests experience a high level of hatchling disorientation. In 1999, 33 of 65 nests (51%) that hatched had levels of disorientation where at least 25% of the hatchlings emerging from the nest cued in on the wrong direction. In 2000, 26 of 58 nests (45%) that hatched were disoriented. This 6% reduction in just one year exemplifies how educating the public about light pollution can directly benefit sea turtles.