Why Did the Sea Turtle Cross the Road?

Last year was a good one for sea turtle nesting in Florida. According to the Florida Fish and Wildlife Conservation Commission, there were 86,870 loggerhead turtle nests, 5,895 green sea turtle nests and 1604 leatherback nests on Florida’s beaches in 2014. Each summer sea turtles crawl out of the ocean and towards the dunes. They dig a nest in the sand, lay a hundred or so leathery eggs, cover the nest with sand and head back to sea. Their motherly duties are over.

Baby turtles dig their way out of the nest a couple months later. If you’re lucky early one morning as you walk the beach, you might catch sight of some late hatchers scrambling madly over each other in their dash to the ocean. This is always exciting to see, because baby sea turtles are really, really cute.

During the nesting seasons of my childhood I saw lots of baby sea turtles, but these sightings were more bleak than cute. I saw the little turtles that lay smashed in the road. These turtles headed west towards A1A instead of east towards the ocean. Why did the turtles cross the road? Now we know that when turtles burrow out of the nest, they head towards the light. For eons (sea turtles fossils have been found that date back 150 million years) the brightest light was the reflection of the moon and stars over the ocean. When street lights, head lights, window lights out-light the ocean, hatchlings become disoriented and scramble off in the wrong direction towards their death.

The good news is that most hatchlings are once again heading in the right direction. We realized our lights were causing the slaughter of baby sea turtles, and we turned them off. Many coastal communities adopted ordinances which ban lights visible from the beach during nesting season. It’s not difficult to keep the beach dark during nesting season. Since this helps sea turtles, most people are happy to comply.

Sea turtles are facing a different problem today: plastic. Young sea turtles will eat anything. If they come across it and it fits in their mouth, they will eat it. When hatchlings leave our dark beaches and swim out to sea, they find a lot of bite-sized pieces of plastic. Like artificial lights, plastic is new. Sea turtles have been swimming the oceans well before mammals made an appearance, but plastic was only first documented in the ocean in the 1970’s. Scientists have found that plastic now makes up 13% of the contents in a hatchling’s gut*. Unfortunately, this is where our concrete knowledge of plastic’s effects on hatchlings ends. Plastic takes up gut space but it isn’t food. Are the hatchlings getting enough to eat? Toxic chemicals like DDT, fire retardants and PCB’s are known to concentrate on the surface of plastic. Are these chemicals poisoning the sea turtles? Are turtles becoming entangled in plastic and drowning? We don’t have all the answers yet.

Sea turtles are hard to study. They are listed as threatened (loggerheads) and endangered (all the others). Every one matters, so they can’t “give their lives to science” or be “written up” like the lugworms from a previous post. Researchers can’t cut into live sea turtles to see what’s happening inside. Hatchlings that die, quickly enter the food chain or sink to the bottom and are never found. They take the answers to these questions with them.

We don’t have all the answers about the effects of plastic on sea turtles, but we also don’t have the luxury of waiting until we do before we act. We need to keep plastic out of the ocean. We can find alternatives to disposable plastic. We can see that our trash is recycled or disposed of properly. We can use the BlueTube at our beach and help keep plastic off the sea turtle menu. We changed our behavior to help sea turtles before. We can do it again.
*Witherington, Blair, Shigetomo Hirama, Robert Hardy, 2012, “Young sea turtles of the pelagic Sargassum-dominated drift community: habitat use, population density, and threats” Marine Ecology Progress Series. Vol. 463: 1-22.