A study being conducted at Sea Life Park could help scientists predict the genders of threatened Hawaiian green sea turtles during nesting season.

Sea Life Park in collaboration with researchers from the National Oceanic and Atmospheric Administration and the University of Alabama at Birmingham have been studying how temperature affects gender determination of Hawaiian green sea turtles as they develop in their eggs.

Researchers say the study is crucial in understanding Hawai'i's vulnerable sea turtle population.

"With the results of this research, we will be able to predict with quite a bit of accuracy how weather patterns impact the reproductive colonies (of the sea turtle)," Renato Lenzi, general manager of Sea Life Park, said yesterday.

Studies prove that the first 20 to 40 days after a sea turtle egg is laid is the most critical time for sex determination. It is during this period that sea turtles develop into males or females while in their egg. It takes 60 days for the eggs to hatch.

Studies also have demonstrated that there is a direct correlation with the temperature of the nest and gender. For instance, warmer temperatures often produce females, and cooler temperatures produce males, said George Balazs, biologist with NOAA's Pacific Island Fisheries Science Center Marine Turtle Program.

However, Balazs said, Hawaiian green sea turtle nests are cooler than those of sea turtles found elsewhere in the world. That would suggest more males than females, he said. But the sea turtle population in Hawai'i is believed to be split equally between males and females.

"This suggests there is a substantial piece of the puzzle that is missing," he said.

In order to determine what the pivotal temperatures are, about 250 eggs laid by 13 sea turtles at Sea Life Park were harvested and divided among three incubators set at different temperatures.

Some eggs have hatched, and the rest are expected to hatch within the next two weeks.

Because it takes more than 20 years for sea turtles to reach full maturity, scientists will have to use a harmless surgical technique to figure out the sex of each individual turtle. Once the sea turtles reach the age of 4 months, scientists will insert a tiny micro-laparoscope — about the size of a strand of hair — into each turtles' sex organ to figure out whether it is male or female, said Balazs.

The data will help researchers determine at what temperatures sea turtles become either male or female and if Hawaiian green sea turtles have lower pivotal temperatures than other turtle populations around the world.

Researchers say the data will help scientists predict how climate changes will affect the sea turtle population years from now, and will help conservation organizations, such as Sea Life Park, respond. For instance, controlled environments, such as those used for this study, could help keep the female to male ratio at 50-50, said Balazs.

"Scientifically, we want to understand the interaction between climate and the sea turtle population. Where conservation is important, we will be able to respond using this new information," Lenzi said.

The turtles are expected to be released into the Pacific Ocean at the end of the study.

Another study is expected to be conducted next year.

Reach Loren Moreno at lmoreno@honoluluadvertiser.com.