Loggerhead turtles are SHRINKING - but it may be a good sign!

Loggerhead turtles appear to be getting smaller - but this could be a sign that numbers are increasing.

A study has found that the average length of the endangered sea turtles has reduced by about 0.94 inches (2.4cm) over the last 11 years.

Scientists from Deakin University in Australia believe this could be due to an increase in first-time mothers, who tend to be smaller than turtles returning for their second and subsequent nesting seasons.

They are hopeful this is a result of conservation efforts in Cape Verde, where the study took place.

Reductions in the size of other species, like fish and rams, is thought to be the result of over-harvesting or trophy hunting for their valuable horns or tusks.

However, these researchers believe that their result is a positive indication of the vulnerable loggerhead turtles bouncing back.

Data was collected from the island of Sal in the northeast of the Cape Verde archipelago, one of the world's largest sea turtle rookeries.

They measured the curved carapace, or shell, length and width of female turtles over the five-month nesting period in nightly beach surveys from 2009 to 2020.

The estimate growth rates of females was calculated, and they used statistical modelling to discern long term trends.

The mean curved carapace width was found to shrink over the years, with the average size of the smallest 10 per cent of turtles decreasing by 0.66 inches (1.7cm). 

However, it was found that the annual number of nests on Sal has increased rapidly from 506 nests in 2008 to 35,507 nests in 2020 - a 70-fold increase.

This proves the size decrease was not the result of the removal of larger size classes of turtles by human intervention.

The researchers believe that the increase is a the result of a boom in first-time nesters, that are often smaller than experienced nesters.

While the new mums are driving the average size of the sea turtles down, their presence could be signifying a growing population.

This could be thanks to the onset of protection of loggerhead turtles on nesting beaches in Cape Verde.

The protection of adults will not only increase the annual survival rate of adults but will also increase the number of eggs being laid each year, helping to increase their population.