Saturday, October 31, 2020

Sea Turtles Return to Their ‘Birth’ Spot on the Beach


Photos by Mary Nelson and Maura Kraus (MPT-18-049) | The sand on this sea turtle’s back indicates she has “nested.”

Mary Nelson, aka, Marco Island’s Sea Turtle Lady, gave an early season sea turtle update to Marco’s Beach and Coastal Resources Advisory Committee. She has seen a lot of false crawls and successful sea turtle nesting since she started monitoring Marco’s sea turtles in 1995. She has also seen a lot of changes to the beach and to the island.

A hatchling emerging from the shell.

According to Mary, during the night, when it is dark and quiet, the female sea turtle comes ashore to lay her nest. Instinct drives her to find the spot where she was born. She crawls across the sand in a slow alternative gait and when she finds the spot, she removes the top layer of sand. With her hind flippers, she scoops out a cupful at a time and sets it to one side. The other flipper does the same until she can’t reach anymore sand, about 18 inches deep and close to eight inches in diameter.

She positions herself over the cavity and starts dropping her eggs until the cavity is filled, averaging about 120-125 eggs per nest. When done, she will cover the cavity with her back flippers packing it very firmly and with her front flippers she tosses sand over the cavity. Slowly she goes back into the gulf, and the sand on her back is an indication that she has nested. The entire process takes about an hour. She does come back to the beach in about 10-14 days and lays another nest, and may do this three to seven times in one season.

Mary reported that there are five marked nests on Marco Island; two at the Marriott Crystal Shores and three on Sand Dollar Island. Last year Marco Island had 121 nests, but had twice as many false crawls as nests. False crawls mean that something is disturbing the sea turtles and causing them not to nest.

Sea turtles use the natural light reflecting off the water in order to orient themselves. Artificial lighting not only deters females from nesting but also disorients hatchlings leaving the nest. Disorientation is an important clue that a lighting problem exists on a beach.

Why so many false crawls?

  • Noise and activity at the beach at night.
  • Objects on the beach left overnight.
  • Barriers such as sheds and trailers along the dune line.
  • Lights on the beach. Marco has become very bright at night.

How can you help? Keep the beach clean, dark and quiet.

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