Biological Clock discovered in Turtles!

biological hawksbill turtle photo credit: hawksbill turtle Photo credit: http://www.earthtimes.org/newsimage/hawksbill271013.jpg:

photo credit: hawksbill turtle Photo credit: http://www.earthtimes.org/newsimage/hawksbill271013.jpg

So women, we all know we have a biological clock, right? Well, researchers have now discovered turtles have one too! When radiocarbon dating the shells they discovered a lot about the turtles! They were able to determine the growth rates, ages, and their biological clocks. For those of you that do not know what this is, it is the reproductive maturity of a species.  The study was led by Duke University and NOAA researchers.

It turns out that this is much more accurate than previous methods. This may also help researchers in finding out what is causing the decline in some turtle’s population.  Kyle Van Houtan, fisheries research ecologist at NOAA’s Pacific Islands Fisheries Science Center, stated, “The most basic questions of sea turtle life history are also the most elusive.”  Kyle is also the adjunct associate professor at Duke’s Nicholas School of the Environment.

Kyle and his colleagues found the biological clock in the hard tissue of turtle shells. They had collected 36 deceased hawksbill turtle shells. They had been collecting since the 1950s, the turtles died naturally or were killed for their shells. There was a time when shells of turtles were taken in the global tortoiseshell trade.
since the 1950s. They used many methods to obtain the shells. Police, federal agencies, and museums worked with the researchers on this project.

Throughout the years it has been less difficult to determine the biological traits of the turtles. This is due mostly to the decrease of carbon-14 in the shells, that was a result of the Cold War.

The researchers were able to determine a median growth rate, and the biological clock, or the age of sexual maturity in the samples. They did so through comparison of the radiocarbon measurements of them, compared to living captive populations.

The team was the first to use this method to determine age, maturity, and growth in turtles. Before this less precise ways were used to determine age, such as the length of the turtle. Another method was looking at incomplete growth layers in tissue of hollowed bone.

This discovery was published in the Proceedings of Royal Society B on January 6th.

This method is not only believed to be more reliable for determining turtle’s age, maturity and growth. It is also something that Van Houtan feels will explain why some species are not rebounding well.

They have determined that the hawkbills in Hawaii start breeding later than other hawkbills around the world. It is estimated that they breed at 29 years, which is much later than other populations elsewhere. This is why Kyle believes this population has not bounced back yet. They also discovered that the diet of the turtles in Hawaii is significantly different. They were at one time omnivores, and have now mostly switched to being herbivores. The food supply is in decline and that would result in a decline in growth.

The research was created mainly for Hawaiian hawksbills, but could help other sea turtle species worldwide.

 

Hawksbill specimens used in the study were collected in accordance with guidelines mandated by the U.S. Endangered Species Act.

Sources:
https://nicholas.duke.edu/about/news/biological-clock-discovered-sea-turtle-shells