Celebrating World Sea Turtle Day

World Sea Turtle Day is on June 16th, and it is also the birthday of Dr. Archie Carr, known as the “Father of Sea Turtle Biology.” Dr. Carr has devoted his entire career to the research and conservation of sea turtles and much of what we know about sea turtles’ biology and life cycle is credited to his research, teaching and writing.

There are seven sea turtle species: loggerhead, green, leatherback, hawksbill, kemp’s ridley, olive ridley and flatback. Of these, five are commonly seen in Florida and are listed as either threatened or endangered - loggerhead, green, leatherback, hawksbill and Kemp’s ridley. Not far from Marco Island is one of the longest-running sea turtle monitoring research projects in the nation. The Conservancy of Southwest Florida’s Sea Turtle Program has documented over 380,000 hatchlings emerging from the coastal barrier beach on Keewaydin Island since its inception in 1982.

They call Dave Addison “Mr. Sea Turtle.” He has been involved in sea turtle conservation efforts for four decades, and a conversation about sea turtles is not complete without his insights. Though he semi-retired in 2021, Addison is still out on Keewaydin “showing season staff how things work” by helping to mentor the group of young biologists hired each year. When talking about sea turtles, his eyes light up and become animated talking about the challenges of a “good night” on the island caging nests to prevent predation by raccoons and monitoring the beach for the presence of feral hogs.

Can you imagine a world without sea turtles? “I’d rather not,” Addison replied. “They are iconic, charismatic animals, and they have a lot of appeal to people. Sea turtles are part of the web of life on this planet and vital to the ecosystem of the ocean; they function by doing what they’ve always done for over 110 million years and I don’t want to think about life in the world’s oceans without sea turtles.”

According to Addison, “Part of the mystique of sea turtles is they seem to magically appear on the beach at night to lay their eggs and then disappear and come back in 10 to 14 days to nest again, and once nesting season is over, they mysteriously disappear for two to four years until they are ready to begin another cycle of nesting.”

 “She’s a loggerhead that was first tagged on Keewaydin in 1988,” Addison says about Emily. “In 2009, we outfitted her with a satellite tag to find out where she stayed when she wasn’t nesting on Keewaydin. It turned out that her home foraging area is about 30 miles south of the southern tip of Andros Island in the Bahamas.” According to Addison, “Emily has a high fidelity to Keewaydin Island, and over the past 31 years, she has been documented as having nested on Keewaydin over 13 reproductive seasons, with the last being in 2019.”

During that time, Addison has learned a lot about Emily’s life. For example, the 47 known nests she laid over that time collectively contained a total of 4,878 eggs which resulted in 3,940 hatchlings reaching Gulf waters for their chance at becoming really big turtles. Available records also indicate that Emily probably laid an additional 10 nests, which most likely resulted in another 895 hatchlings for a total of 4,835 little loggerheads.

 “With a generally accepted rate of 1 in 1,000 hatchlings reaching adulthood, it took Emily 31 years to reproduce herself four or five times,” said Addison. “By now, it may well be that one of Emily’s offspring has come back to nest on Keewaydin to continue her lineage.”

What’s so special about Keewaydin Island for the sea turtles? According to Addison, “Just like other undeveloped barrier islands, Keewaydin beach functions like threads on a bulldozer - it can either roll forwards or roll backwards depending on their response to conditions in the coastal zones and can perpetuate itself better than a developed beach. Though there are some homes on the island, it is not as developed, like Naples and Marco Island, and doesn’t experience the “erosion” issues we’ve read about on developed beaches.”

Important lessons learned from Keewaydin sea turtle research? “Don’t stop!” Addison said. “The longer the database continues, the more interesting it gets. With the use of satellite tags and other tracking devices, we are able to identify trends and find unique and surprising stories like Emily.”