Professor Joe Nairn hopes he can one day bring his 5-year-old granddaughter to see loggerhead sea turtles nesting along Georgia’s coast.
“I want her to be able to see sea turtles,” Nairn said. “I can’t wait to take her.”
Last month, the University of Georgia Sea Turtle DNA Fingerprinting project received the President’s Award from the International Sea Turtle Society. The ISTS is a nonprofit organization committed to sharing the importance of sea turtles with the world and working toward improving sea turtle protection and conservation.
“This is the only project of its kind that I know of in the world where we’re able to identify all the adult females in the population based on genetic tags, so it’s definitely unique,” Georgia Department of Natural Resources senior wildlife biologist Mark Dodd said.
The project developed over a decade ago from the minds of Dodd, Nairn and Warnell School of Forestry and Natural Resources assistant research scientist Brian Shamblin.
“We had some questions that we felt like we needed answered and so it was just a natural collaboration,” Dodd said of the groups’ formation in 2008.
Shell-ibrating the discovery of DNA extraction
Shamblin discovered how researchers could extract female DNA from the eggshells of sea turtles in order to track the mothers’ locations, the number of nests they lay each season and how long they have been reproducing — in essence, taking the turtle’s fingerprint.
The Georgia Department of Natural Resources reports the nesting season for Georgia’s sea turtles runs from early May through mid-Aug. Female sea turtles don’t reach reproductive age until 30 years old but can lay up to an average of four nests with 120 eggs per nest every other season.
According to Nairn, the southeastern U.S. hosts the world’s largest nesting aggregation of the loggerhead. After sea turtles leave their nests and venture into the water, they will only lay their eggs at the beaches where they hatched.
“If we lose our population in Georgia, we're not going to replenish them with turtles from other places,” Nairn said.
The fingerprinting project tracks female loggerheads along the coast of North Carolina down into northern Florida, an area Nairn called the Northern Recovery Unit.
Before genetic tagging began, Nairn said the hardest part of tracking sea turtles was filling in the period of time from the moment they leave the nest until they return to shore to reproduce.
“They basically drift around the whole Atlantic Ocean. They go over off the coast of Europe, and then they eventually kind of drift back,” Nairn said. “The idea has always been the turtles will return to the beach where they were hatched to nest.”
Protecting the future of Georgia sea turtles
With this project, Nairn believes they can continue to monitor sea turtles and track female nesting patterns to prevent the population from drastically fluctuating.
“Up until the early 1990s, we had a 20-year decline in our population numbers, and there was a very real concern that we were going to lose this population,” Nairn said.
Scientists are now able to track the reproductive cycles of both mothers, daughters and even granddaughters through genetic tagging. One turtle who goes by the name Big Bertha has been reproductively active since the 1980s, Nairn said.
“Now that we've been doing this long enough, we're seeing those turtles that have been gone for years showing back up,” Nairn said.
At the Georgia DNR, Dodd has also played a role beyond the project to ensure the safety of sea turtles along Georgia’s coast.
The commercial shrimp trawl industry is one of the lead causes of turtle mortality, Dodd said. Part of the reduction in the mortality rate has come from turtle excluder devices, or TEDS. The TEDs are metal grates that prevent sea turtles from getting lodged in the shrimping nets.
“We do a lot of the research that tries to identify the threats to these populations,” Nairn said, “Then that information can be used by management agencies to try to develop conservation avenues that will help to protect the turtles.”
Sea turtles are an indicator species, both Nairn and Dodd explained. They alert scientists to the effects humans have on the ocean ecosystem.
“They are telling us something, so ultimately by protecting loggerheads we’re protecting the ecosystem upon which they, and also we, depend,” Dodd said. “There’s also the philosophical argument that they’re a species that evolved on the planet alongside us and that we should do everything we can to maintain as many components of that ecosystem as possible.”