Posted by Rick Civelli | 01.30.2012 | Turtle Talk

An Ocean of Female Sea Turtles?

Despite the prospect of global warming skewing hatchling gender ratios in upcoming years, there is some good news for sea turtle conservationists. New research published in the Proceedings of the Royal Society B at least one species may have a way to counteract the presence of female predominated nests.

Warmer temperatures mean warmer nests. Warmer nests mean more females, as sea turtle sex is temperature dependent. This could lead to a scarcity of males and therefore result in an inbred population (with few males to go around, many hatchlings would share the same dad). Examples of green sea turtle nesting in Cyprus, however, show that inbreeding need not occur.

In a country where the sizzling summer temperatures routinely result in nests composed of up to 95% females,  the population still remains genetically diverse. Since female turtles are able to be fertilized by more than one male and produce offspring from both, they can broaden the gene pool. Of the 20 nesting females monitored by Wright et al. they had eggs fertilized by an average of 1.4 males.

The highly migratory nature of sea turtles also plays to their advantage here, as males logged thousands of miles in just one nesting season. Therefore warmer nests need not result in an ocean absent of male sea turtles.