1 in 100 hatchling sea turtles leaving Hilton Head Beach will survive 3 days. It is critical to get as many hatchlings into the surf as possible so that the lucky one can get past the predators. Sea Turtle Patrol HHI aims to prevent the misorientation of hatchlings by educating residents and visitors about the consequences of artificial light visible from the beach. Hatchlings use vision to find the open horizon over the ocean where the moon reflects on the water. Naturally, this would be the brightest light. Thousands of hatchlings will not reach the water each season due to lights visible from the beach that are left on after 10pm.
life of a loggerhead
The mother loggerhead emerges from the sea and drags her 400 lb body up the beach to the dry sand. She will dig an egg chamber for approximately 120 eggs with her back flippers. The eggs are soft and leathery and do not break when they are dropped into the 2 ft deep egg chamber. They start incubating without gender and within the 2nd 1/3 of incubation, the temperature of incubation will determine their sex. If they incubate above 84.2 °F in that critical time period, they will become female, and below 84.2°F, they will become male. “Chicks are hot and guys are cool.”
ENTERING THE WATER
There is a long journey ahead and it begins with the orientation toward an open horizon and positioning into the waves that roll onto shore. Heading opposite of the wave rotation will direct them off shore toward the Gulf Stream. To reach this major current, they will swim 70 miles which takes approximately 3 days. It is estimated that 1 in 100 will make it to the Gulf Stream without being predated (eaten).
HOPPING THE GYRE TO THE JOURNEY BACK HOME
Arriving as dinner plated sized hatchlings, they have grown rapidly during their stay in the Azores. These 10-15 year old sub-adults are now about 2.5 ft long and will grow very slowly for the rest of their lives. They instinctually find the North Atlantic Gyre again and follow it all the way back across the Atlantic to the Eastern seaboard of the United States. They find a spot that provides adequate food and forage until they are approximately 30 years old!
HATCHING & EMERGENCE
The eggs will hatch under the sand after about 60 days. The hatchling has an egg tooth that rips the eggshell open. They uncurl their shell and it hardens as it dries. After approximately 3 days of hatching within the egg chamber, the hatchlings will emerge from the nest chamber through about a foot of sand. A drop in temperature will prompt their emergence. Reptiles are cold-blooded and cannot manage their body temperature internally, so they can make their way to the sea when the sun is not heating up the beaches; usually after sunset.
NORTH ATLANTIC GYRE
TO THE AZORES
The Gulf Stream provides shelter in the sargassum weed that floats in it and there are plenty of small organisms that the hatchling can feed on. They will rest for a time and float north in the current. When they are rested, they will swim with the current and cross the Atlantic. Their destination is an isolated island chain off of the coast of Portugal called the Azores, and it could take them up to a year to get there!
The male loggerheads will never come back to shore, but the females will become sexually mature around the age of 30 to lay their own eggs in the dry sand. They will find the Earth's magnetic signature that they imprinted during their first journey to the Gulf Stream and return to that area. Hatchlings entering the ocean in Georgia, South Carolina, and North Carolina will consider all 3 states to be the "beach that they were born on". Some of our loggerheads lay a nest in all 3 states in the same summer!