OCEAN RIDGE — The best beaches for people can be the most treacherous terrain for newly hatched turtles searching for the sea, environmental analysts say.
That is one explanation for preliminary data showing that 1,784 sea turtles hatched in Ocean Ridge this year wandered lost — falling to predators, dehydration or exhaustion before reaching the water.
Why? Among other reasons: no towering condos to block the disorienting glow lighting the sky from neighboring areas, as hatchlings navigate the comparably wider beaches of this town, where a road and dune separates mostly single-family homes from the shoreline.
That, however, is not the entire story, as local turtle counters continue to tally the losses and successes of the season that officially ended Oct. 31.
Ocean Ridge’s total represented a 46 percent increase in disoriented hatchlings from the year before, according to numbers from the Palm Beach County Department of Environmental Resource Management. Delray Beach also saw a steep rise, with 542 lost hatchlings.
Those came from 19 nests in which disorientations were recorded, county environmental analyst Carly de Maye said.
Two of those were attributed to a light from a home near the southern end of the beach, said John Fletemeyer, who has recorded sea turtle counts in Delray Beach for the last 25 years. No single cause could be identified for the others, which were attributed to ambient sky glow, he said.
Topped in the last two years by Boca Raton and Singer Island only, Ocean Ridge has consistently counted more disoriented turtles than most other county towns for which data were available. Neither Gulf Stream nor Briny Breezes has given data on hatchling disorientation in the last two years, but it is not clear if that is because there were no disorientations or because they weren’t counted, de Maye said.
A number of factors influence the differences sea turtle data collectors see year-to-year and town-to-town, and weighing the influence of each can be tricky, she said.
More rain this year likely washed away more hatchling tracks before they could be counted in some towns. At the same time, responsibilities of turtle counters can vary from town to town. Those responsibilities, including completing a count of nestings and hatchings quickly enough to allow beach cleaners time to rake the beach, can make getting a full count of disorientations difficult, she said.
At the same time, Jean Higgins, an environmental analyst for the state Fish and Wildlife Conservation commission, said that data on disoriented hatchlings are becoming more accurate with improved training and greater awareness of the challenges that beach renourishment projects and development present to newly hatched turtles.
Often uncounted, though, Higgins said, is the impact of "sky glow” on mother turtles’ decisions not to nest on a beach — a false crawl — or disorientation that could leave her exhausted and vulnerable even after she returns to the water.
And, of course, Ocean Ridge’s higher than average numbers do not suggest that towns fronted by high-rise buildings necessarily present a more turtle-friendly environment.
Singer Island, with its nearly unbroken line of hotels and apartment towers, has consistently seen the highest numbers of disoriented hatchlings in the county, according to de Maye. That is likely due in part to higher numbers of tourists, less familiar with the need to keep light off the beach during turtle season, she said.
She adds that though environmental officials can enforce rules to keep lighting off the beach only from March 1 to Oct. 31, nests continue to hatch into November. She suggests residents keep an eye out for unhatched nests and adjust lighting appropriately.
Final numbers on hatchling disorientation are expected later this month.
— Antigone Barton
Light Info: Coastal lighting should be minimized during the sea turtle nesting season (March 1 to Oct.31 in Palm Beach County). Lighting visible from the beach can deter female turtles from nesting, and can cause hatchlings to travel in directions other than directly to the water, causing predation, dehydration and exhaustion. Coastal properties should appear dark to a turtle’s perspective, not actually be dark. Techniques such as redirection and shielding can be used to provide light that is not visible from the beach.
Questions regarding turtle-friendly coastal lighting can be directed to ERM’s coastal lighting coordinator at 561-233-2400.
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