Shifting Sands of Time

On Friday, March 7, 2025, at the Marco Island Library, the Marco Island Shell Club welcomed Dr. Jeffrey Schmid, an Environmental Research Monitor at the Conservancy of Southwest Florida to talk about the Loggerhead Sea turtles and how they have adapted to changes brought about by several hurricanes and tropical storms.

The Conservancy’s Sea Turtle Program is one of the longest continuously monitoring research projects in the world. According to its website, “Since the program’s inception, they have documented over 380,000 hatchlings from Keewaydin Island reaching the Gulf of Mexico waters for their chance at becoming adults.” According to Dr. Schmid, this is the 43rd year of the Conservancy’s monitoring program on Keewaydin Island.”

During the sea turtle nesting season (May-October) the Conservancy has a unique program at Keewaydin Island by monitoring the nesting beaches at night. According to Schmid, this gives them the opportunity to encounter the female sea turtles as they are crawling out of the water into the beaches to deposit their eggs. Riding on ATVs, they locate the nesting female by following her tracks, attach tracking tags, and measure the adults. This will give the team valuable information about their location and nesting patterns. 

According to Schmid, once an egg chamber is located and verified that she did lay eggs, the team digs a little trench around the egg chamber and sets a metal cage down to bury the lower part to keep predators such as coyotes and raccoons from digging the nest. Once a female lays her eggs, it takes about two months for the embryo to develop and hatch out of their eggs.

Their pattern is for all 70-100 hatchlings to pop up all at once to overwhelm any predator that might be on the beach, Schmid added. One might get picked up by a ghost crab at night but all the others get to the water where there is a host of other predators waiting. They will spend several years riding the currents and then move into our coastal estuaries where they grow up and mature and then move further offshore as adults and come back to their nesting beaches – that takes about 30 years!

The sea turtle season is also SW Florida’s tropical cyclone season (June to October). High tide, onshore surges, and strong winds all leave drastic consequences on the nesting beaches. According to Schmid, sea turtle nests can stand a brief inundation as long as it drains – but long-standing water drowns the nests. When Tropical Storm Debbie hit SW Florida in early August 2024, 40-50% of sea turtle nests were lost in Keewaydin Island. The storm eroded beaches and the sand is pushed further back behind the vegetation line. Turtles coming into the nest may crawl further up the beach to deposit their eggs. 

Dr. Schmid shared a bit of history on Keewaydin in the 1970s. Keewaydin’s shoreline was overgrown with non-native Australian Pines that were later removed by the state in the late 1990s. They have a shallow root system that branches out. After a storm, they would fall over, creating a barrier for nesting sea turtles. Though most of the Australian pines have been removed and native vegetation has come back, leftover Australian pine stumps still appear in the tidal area after tropical storms. The trees have not moved, but the beaches and dunes have migrated inland – which gives you an idea of the inland migration of beaches. Similar to the “dome homes” formerly on Cape Romano, is a classic example of the dynamic nature of our beaches.

This got me thinking about the hatchlings crawling back to these beaches as mature females in another 30 years, Schmid said. Year after year they have come back to Keewaydin to nest. These are resilient creatures.