Just as they have for millions of years, sea turtles by the thousands made their labored crawl from the ocean to U.S. beaches to lay their eggs over the past several months. This year, record nesting was found in Florida and elsewhere despite growing concern about threats from climate change.
In Florida, preliminary state statistics show more than 133,840 loggerhead turtle nests, breaking a record set in 2016. Same for green turtles, where the estimate of at least 76,500 nests is well above the previous mark set in 2017.
High sea turtle nest numbers also have been reported in South Carolina, Alabama, North Carolina and Georgia, although not all set records like Florida, where Justin Perrault, vice president of research at Loggerhead Marinelife Center in Juno Beach, said the number of nests is remarkable this year.
In most species, sex is determined during fertilization. However, the sex of most turtles, alligators, and crocodiles is determined after fertilization. The temperature of the developing eggs is what decides whether the offspring will be male or female. This is called temperature-dependent sex determination, or TSD.
Research shows that if a turtle’s eggs incubate below 27.7° Celsius (81.86° Fahrenheit), the turtle hatchlings will be male. If the eggs incubate above 31° Celsius (88.8° Fahrenheit), however, the hatchlings will be female. Temperatures that fluctuate between the two extremes will produce a mix of male and female baby turtles.
Researchers have also noted that the warmer the sand, the higher the ratio of female turtles. As the Earth experiences climate change, increased temperatures could result in skewed and even lethal incubation conditions, which would impact turtle species and other reptiles.
Thank you for pointing this out. I feel like so many folks don’t understand this crucial piece of information.
