HARBOR BRANCH - OFFICIAL PRESS RELEASE

WHERE THE TURTLE BOYS ARE - FAU SEA TURTLE EXPERT TO DISCUSS SURPRISING RESULTS OF NEW STUDY

At a free Harbor Branch lecture on Wednesday, Nov. 16, Florida Atlantic University researcher Jeanette Wyneken will describe some surprising and even controversial results from an ongoing 4-year Florida sea turtle study. The overall goal of the research is to identify critical needs for improving sea turtle conservation efforts.

One key focus of the project has been the sex ratios of turtle hatchlings, because managers need to understand if there is an adequate ratio of male to female turtles to maximize reproduction and maintain needed genetic diversity. Current management plans make the simplistic assumption that turtle sex ratios average one to one, though in reality this is not the case. Turtle sex, as with many other reptiles, is determined not by chromosomes but by the temperature at which turtle eggs incubate, with male sex triggered by cooler temperatures. For this reason, conventional scientific thinking has long held that most male turtles in the Atlantic must be hatched in cooler northern climes.

Wyneken and her colleagues have made the surprising discovery that, though there is year-to-year variability, the ratio of Florida hatchlings averages roughly two males to three females, which is much higher than expected. "We're taking 20 years of dogma and saying, 'Wait a minute, when you actually get to take a large and detailed look, the simple ideas about sex ratios don't work, '" says Wyneken. As yet, Wyneken says she does not have an explanation for the high number of male hatchlings, but she hopes continued research will offer answers.

Another element of the Wyneken study has been analysis of data from teams along the Eastern seaboard that monitor turtle nests. Happily, there was no indication of there being too few males, which would lead to researchers seeing high numbers of unfertilized eggs. If such a problem was revealed at some point, though, a possible management solution would be to incubate eggs in laboratories in cooler temperatures that produce more males, then release those animals to the wild. "But we hope it never comes to that," says Wyneken.

The main reason knowledge of sea turtle sex ratios has been lacking is that sex is impossible to identify by sight until the animals mature at about age 25. Even endoscopic exams couldn't be done until turtles were at least half grown. The only alternative had been to sacrifice hatchlings to determine their sex anatomically but for obvious reasons researchers were loathe to take this path, particularly with an endangered species. To get around the problem, Wyneken developed a procedure involving microlaparoscopic surgical techniques, like those commonly used to perform knee and other surgeries on humans, to determine hatchling sex and still be able to return them healthy to the wild.

The research Wyneken will describe is new and under review in the scientific journal Herpetologica

Jeanette Wyneken is an Assistant Professor of Biological Sciences at Florida Atlantic University in Boca Raton. She has more than 20 years of experience studying sea turtle biology and conservation. Wyneken has written two books on sea turtle anatomy, co-edited the Biology of Sea Turtles, and has published widely on sea turtle anatomy, behavior, and ecology. Every May she teaches Harbor Branch's summer course on sea turtle biology.

Wyneken's presentation, Sea Turtles and Sex Ratios: ... Where the Boys Are, will be at the Johnson Education Center on the Harbor Branch campus, 5600 US 1 North, Fort Pierce, at 7:00 p.m. on Wednesday, Nov. 16. A reception will follow and there is no charge to attend. Please direct press inquiries, including interview and material requests, to Mark Schrope at 772-216-0390 or schrope@hboi.edu. Public questions about the series should be directed to the Marine Education Office at 772-465-2400 ext. 506 or education@hboi.edu.

HARBOR BRANCH Oceanographic Institution was founded in Ft. Pierce, Fla., in 1971 to support the exploration and conservation of the world's oceans. The institution has held to this mission and grown into one of the world's leading oceanographic institutions with a 500-acre campus, over 200 personnel, and a fleet of sophisticated research ships and submersibles.