Dreaming of the Sargasso Sea

This will not be my first mention of the sea turtles that nest along Florida’s east coast, especially along the stretch of beach just under my nose. When I left home at 8:00 this morning for my usual walk on the beach, the sea turtles were not really on my mind, and a surprising encounter with biologists, nests and eggs was far from my thoughts.

There is a blue-roofed beachhouse a mile and a half south of me, and for almost two months it has been my ‘turn-around’ marker. As I approached that spot this morning I noticed a jeep stopped there, and three people very carefully digging in the sand. I realized right off that it was a team from the Volusia County turtle watch, and that they had just come upon a new deposit of turtle eggs buried by a female turtle during the night. I quickened my pace, eager to catch as much of the event as possible.

I got to the nest maybe five minutes before the two graduate students and their senior located the cache of about ninety eggs. For the next thirty minutes I watched (and took pictures) of the gradual uncovering of the eggs. They were digging the eggs up this time because the mother had chosen a bad location, too close to the surf, and in an area of known raccoons, a natural predator. What was especially interesting about these Loggerhead eggs was the size, and the number of fused eggs. Normal turtle eggs look very much like a ping pong ball, but the eggs this time were in many cases extra large. Not only that, but a good many of the eggs were fused together. This in itself is not all that unusual I learned, but it is more commonly just two eggs. There were three and four eggs fused together in this nest.

The scientists were working as fast as possible (uncovering progresses in a manner much like that on an archeological dig—slowly) because exposure to the air, light and temperature is detrimental to the eggs. They had a site already selected for re-burying the eggs a moderate distance south along the beach. Better conditions all around.

Turtle nesting season runs from early May through late October. As of this week sixty-four nests have been logged and roped off. According to the figures from the Fish & Wildlife Agency, the 2009 nest total along Florida beaches was 52,374 for Loggerhead turtles, a number 40% below the 1998 total. Temperature is very important for the hatching of eggs. Ocean temperatures influence mating, as well as when the female comes ashore to deposit the eggs. Temperatures within the nest are relevant to determining the sex of the hatchlings. Warmth at the top of the nest results in females; cooler temperatures near the bottom produce males. Beaches in Volusia County are vital because the white sand is slightly cooler than the sand farther south.

As for predators, the newly hatched turtles run a gauntlet for survival, racing against the sea birds, raccoons, crabs, and once in the water, against fish and sharks. From a nest of 100 eggs only a handful will survive. Those babies who make it through all the hungry obstacles swim straight out to the Sargasso Sea, where they eat and grow for a year or longer. This is a region of the western Atlantic between the Azores and the Caribbean, so called for the abundance of Sargasso seaweed, its deep blue color and exceptional clarity. Blue heaven for newly hatched sea turtles.