Scientists fret over side effect of ‘exceptional’ sea-turtle nesting season: ‘It worries the crap out of me’

Sea turtles are experiencing something of a baby boom. According to the New York Times, preliminary data suggests there were over 74,300 nests on Florida beaches during this year’s nesting season. That’s 40% higher than the previous record, set in 2017.

Because sea turtles don’t reach sexual maturity until their 20s or 30s, this increase in nests can likely be attributed to conservation measures implemented in the late 1970s.

“The increase is an explosion,” said Simona Ceriani, a research scientist who coordinated the annual survey for the Florida Fish and Wildlife Conservation Commission.

In addition to more nests, experts have noted that an overwhelming majority of the turtles hatching in recent years are female. Dr. Jeanette Wyneken, a professor at Florida Atlantic University and turtle expert, reported that between 87-100% of the hatchlings tested in recent years have been female.

The influx of female turtles could be caused by rising ocean temperatures. The sex of a young turtle is determined by the temperature of the water the egg develops in, according to the National Ocean Service. Cold water yields males, while warm water yields females.

Turtles are far from the only species affected by warmer-than-average water temperatures. Warm water deprives fish of the dissolved oxygen they need to survive, bleaches coral, fuels algae blooms, and melts sea ice.

It may be the case that the ratio of male to female turtles has long been skewed towards females. Data suggests that over 90% of hatchlings on Florida beaches were female in the 1980s.

In the short term, more females may not be bad news for turtle populations. The more female turtles born today, the greater the population will be in 20 to 30 years. Of course, if there aren’t enough male turtles to fertilize the eggs, the population will suffer.

Unfortunately, Dr. Wyneken’s team has noticed that many hatchlings aren’t hatching. The team suspects the turtles are dying before they can hatch from a combination of extreme heat and drought.

“It worries the crap out of me,” Dr. Wyneken told the New York Times.

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