First known green sea turtle nest found at Papohaku Beach.
Rescued baby honu wait in a bucket to be released.
By Catherine Cluett
Hundreds of tiny tracks mark the sand from the grasses’ edge down to the ocean. They are neither the tracks of a crab, nor the marks of a bird. These footprints belong to baby green sea turtles making the 50-yard trek from their nest to begin their lives at sea.
It was the tracks which alerted a Popohaku home owner and Nature Conservancy volunteer to the turtle nest. George Balazs, a marine turtle research biologist with the National Oceanic and Atmospheric Administration (NOAA), carefully dug a hole in the sand as a group of volunteers peered down into what had been the nest of over a hundred baby green sea turtles. Balazs was looking for clues that might bring insight to the genetic distribution of green sea turtles on Molokai.
There are three genetic fingerprints of green sea turtles, or honu, found in Molokai waters. One of these variations makes up about 70% of the overall population, says Balazs, while the other two are much less common, each comprising about 15% of green sea turtles around the island.
Balazs has been tracking the DNA makeup of turtles found on Kawa`aloa Beach, just west of Mo`omomi, for the past several years. The discovery that every single nest so far has belonged to one of the two less common DNA groups is a fact he says is surprising.
Sea turtles normally go back to where they were born to nest — “but not perfectly,” explains Balazs. If all turtles only nested where they were born, the species would never spread. Some turtles have to break the pattern.
The homogeneous DNA thread found on Kawa`aloa Beach means, Balazs explains, that one mother turtle started nesting there, called a “founding turtle,” creating a new colony. Green sea turtles don’t reach sexual maturity until the age of 25 to 40 years old. So 30 years after the founding turtle first nested there, her offspring came back to nest at the same site, creating a legacy of the same DNA fingerprint.
The nest found on Papohaku was the first recorded hatching on that beach. Balazs is curious to find out whether those turtles belong to the same genetic group as those nesting at Kawa`aloa. To get this information, volunteers, under Balazs’ supervision, dug up the nest after the young had already hatched, and collected a sample of partially developed or decomposing eggs from which to extract DNA.
Statistics were also gathered about how many eggs were laid (99), and how many of those hatched successfully (over 90). In addition, five baby turtles were rescued from the nest that probably wouldn’t have made it otherwise, says Balazs.
After hatching, sea turtle young work collectively to dig out of the nest. But eggs laid on the periphery are at a disadvantage because they are not surrounded by the warmth of their fellow developing nest-mates during the 60-day incubation period. These eggs may hatch a little later than eggs in the middle of the batch, explains Balazs, and may account for the few babies left behind.
Balazs and Nature Conversancy volunteers released the five hatchlings into the ocean and watched as the tiny bobbing heads made their way out to sea.
Usually, he says, researchers don’t interfere with nature’s course. But giving five extra green sea turtles, a species on the brink of extinction only 30 years ago, a chance to survive in the wild, is a rewarding bonus of the job. There are many predators that prey on the tiny sea turtles. But, as one volunteer said, “we did our best. And that’s all we can do.”