50,000 hatchlings started their lives on Cayman’s beaches in 2017’s record-breaking turtle nesting season, but only a tiny fraction will survive to return to reproduce.
The odds don’t stack up well for a hatchling. Just one in one thousand will survive to maturity. With those odds, we can expect around 50* of this year’s estimated 50,000 hatchlings to reach reproductive age.
While this year’s record-breaking numbers are a continuation of a very positive trend, the Department of Environment warned that artificial lighting is cutting into their already slim chance of survival.
An average sea turtle lays around 100 eggs per clutch. The DOE told Cayman 27 it is seeing hatch rates of between 70 to 80 percent, so with 682 nests for the year, 50,000 hatchlings is a reasonable estimate. This year the DOE documented 30 instances of mis-orientation, where hatchlings follow artificial lights in the wrong direction. That’s an estimated 2,200 or 4.4% percent of this year’s hatchlings likely died of exhaustion or dehydration from artificial lighting.
The DOE said that figure may even be low.
“There are many many more incidences that are never detected because they occur on beaches at night all around the island, and they are very difficult to detect in all instances,” said DOE Research Officer Janice Blumenthal.
Only time will tell how many of this year’s hatchlings will one day return to Cayman as adults, to continue the cycle of life for these iconic animals.
Author’s note: an earlier version of this story miscalculated the number of turtles likely to survive to adulthood. 1 in 1000 is the general likelihood of survival for hatchlings, meaning only 50 of 50,000 would be likely to survive to maturity.