New Research about Loggerhead turtles

 Loggerhead turtles take almost half a century to reach maturity, say scientists.

A female turtle will not start to lay eggs until she is 45. This
estimate, based on examination of several decades of data on 
the turtles' growth, has implications for conservation efforts.
It reveals how long it takes for turtles hatched at a protected
nesting site to return to that site to breed.

Prof Graeme Hays from the University of Swansea, one of the

authors of the study, explained how reaching maturity so slowly

meant that the turtle population was "less resilient" than 

 previously thought.

It is, however, extremely difficult to follow the life cycle of a sea

turtle. These long-lived marine reptiles are impossible track as 

 they drift through thousands of kilometres of ocean, spending

the vast majority of their time underwater. You can't follow one 

individual throughout its life.

Previous estimates of their age at maturity are all over the place, spanning from 10 years to 35 years. It was impossible to get 
some sort of consensus.

To overcome this problem, the researcher and his colleagues

embarked on a three-part data trawl.

To estimate the growth rate of newly hatched turtles, the team

examined measurements of hatchlings at a nesting site in Florida and compared these with the sizes of the same turtles when they had drifted across to the Azores islands in the middle of the North Atlantic. This journey drifting several thousand kilometres on the currents, takes approximately 450 days. The scientists were   able to see from the data they examined how much the turtles grew during that time.

The team also used many hundreds of measurements made by

scientists who had captured, marked and recaptured individual

loggerhead turtles. Using these figures, they were able to chart  

the animals' growth rate.

All of this data enabled the researchers to use the size of mature

loggerhead turtle mothers - measured at several well-studied

nesting sites - to estimate their ages.

These estimates reinforce that animals like sea turtles take a 

very long time to recover from human-caused population declines. So conservation efforts must be appropriately targeted to address the most important threats, and they must be maintained for decades to ensure success.