From Watts Up With That?
This article is a about hypothesis based on folklore and its potential plausibility. It is not presented as a scientific study.
Turtle nesting season has begun in Florida. A bartender, “A”, at my local watering hole is a big turtle enthusiast. So I let “A” know that on my recent walks along the beach, I’ve been seeing lots of new roped-off nests popping up as the nesting season begins.
“A” asked me how far away the nests were located from the water. This is something I hadn’t considered and hadn’t really taken note of. She explained that many locals believe that if a hurricane season is going to be intense the turtles would place their nests up the beach, farther away from the surf than normal. So, a nesting season where turtles lay their eggs close to the high tide line is a prediction for a calm season.
In subsequent walks I paid attention to where the nests are located on the beach. As luck would so have it, this month we had a big flood of seaweed at the same time the King tide occurred. This clearly marked the high tide level making it easy to spot. It turns out that every turtle nest I’ve seen this season are located just above the King tide line.
Sea Turtle Nest on Fort Lauderdale Beach, Florida, May 2023, by Charles Rotter
According to Florida folklore this will be calm storm season. The incubation period for sea turtles is 30 to 90 days. A prediction three months out, and subsequent change in nesting behavior would have a tremendous evolutionary advantage on breeding success.
Nests placed farther than necessary from the water expose the eggs to dehydration and excess predation, especially on that precarious night the young turtles hatch and make a dash for the water. Sea birds and crabs lie in wait for such events.
When nests are placed too close to the water the risk of drowning the eggs occurs,
For the eggs to survive and have a chance of hatching, sea turtles must lay their eggs on sandy beaches. As they are developing, the embryos breathe air through a membrane in the eggs, and so they cannot survive if they are continuously covered with water. https://conserveturtles.org/information-sea-turtles-frequently-asked-questions/#21
as well as the physical danger of being washed away in the storm.
Strong wave action can also cause beaches to erode, washing sand away. This can expose sea turtle eggs, leaving them prone to drying out or predation. They can also destroy the nests completely, washing the eggs into the sea where they will drown.https://blogs.ifas.ufl.edu/news/2020/08/06/sea-turtle-nests-and-hurricanes-here-is-what-uf-ifas-experts-want-you-to-know/
Sea turtles have been around for around 150 million years. If it this level of predictive accuracy for seasonal storm levels were somehow possible, that’s plenty of time for selective pressure to cause turtles to evolve this survival edge. Whatever the turtles may be using to forecast, be it currents, temperature, salinity, barometric pressure, if it’s possible, they would likely have evolved to be able to do it.
We should hope this folklore is true, and then someday we may be able to use the same indicators the turtles use to improve our seasonal storm predictions, (which haven’t been very accurate the last few years).
Addendum. Here’s a photo from July of last year helping errant hatchlings get to the Ocean after they’ve headed in the wrong direction.
Sea Turtle Rescue, July 30, 2020, by Charles Rotter
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