By Mary Pringle for The Island Eye News
Photos by Barbara Bergwerf
For the first time in recorded history a leatherback turtle nested on the Isle of Palms on May 29. Every spring there are a few leatherback nests in the state.
So our Turtle Team has always hoped to have one, and it finally happened at Ocean Club Villas. Those on patrol were Cindy Bergstrom, Patti Horton and Tristi Lowther who found huge tracks about six feet wide on the beach. The eggs were moved to a safer spot in the soft beach sand near Ocean Point along the 18th fairway of the Links Golf Course to incubate.
There has been one other leatherback nest reported in SC this month on Lighthouse Island in the Cape Romain National Wildlife Refuge. Of course we normally have only loggerhead turtles here. The only other species we have ever recorded was a green sea turtle who laid eggs in 1999 not far from 30th Ave. Loggerhead eggs are the size and shape of ping-pong balls, but leatherbacks lay cue ball sized eggs along with dozens of smaller “spacer” eggs with no yolks in the nest with them. We are not sure of the reason for these smaller eggs and they do not hatch.
Leatherback turtles can be over 1000 lbs. and nest in the Caribbean and on a few beaches in Florida in the spring. Then they begin their northward migration to the North Atlantic. Each one can eat over 400 lbs. of jellyfish each day – the weight of an African lion. So their niche in the ecosystem is important in keeping the ocean’s creatures in balance. They are vulnerable to strikes from boat and ship propellers as they make their way through shipping channels and near the shore on the US coast. We have already had five of them wash up dead on our beach after being killed by this watercraft interaction. Fortunately their numbers in the Atlantic Ocean are on the increase, but this species is in real danger of extinction in the Pacific.
We are happy that she was able to nest in the newly renourished sand in Wild Dunes but sad that two of the large eggs appeared to have been cut open by the coarse sand and sharp bits of sea shells as they dropped into the deep hole dug by her rear flippers. These were saved for our genetics research project, which is now in its ninth year. We collect one eggshell from each nest and the female is identified by her DNA. This gives very valuable information to scientists studying sea turtles.
Leatherbacks are unique in that they have a layer of blubber under their black leathery skin, which enables them to feed as far north as the Arctic Circle. Even though they are cold-blooded reptiles, there is a mechanism of heat transfer that allows their muscle action to help keep them warm. It is rather amazing that they can grow to this size with their diet of jellyfish consisting mostly of water. The pointed hooks on their beaks help them grab their slippery prey, and then the sharp pointed papillae in their esophagus and upper GI tracts make it possible for their food to go only one way – down.
Unlike loggerheads who nest about every two weeks during the summer, leatherbacks are known to lay eggs at ten day intervals. It will be very interesting in August to see how many small leatherbacks these huge eggs produce.
Mary Pringle has been the Project Leader for the Isle of Palms/ Sullivan’s Island Turtle Team since 2000. It is one of about thirty nest protection projects under the South Carolina Department of Natural Resources. She is also on the Sea Turtle Stranding and Salvage Network.