From Wildlife Extra:
Young turtles seek warmer climes
March 2014: New study shows where young loggerhead sea turtles disappear to during their ‘lost years’.
Once baby turtles have successfully hatched and made the risky journey to the sea they are rarely seen until they have grown till 40cm, between seven and 12 years later. Yet what happens to them during this period scientists call the ‘lost years’ has remained a mystery until now.
To solve the mystery a team of scientists, led by Katherine Mansfield of the University of Central Florida, attached solar-powered transmitters to 17 turtles collected from nests along the south-east coast of Florida. The team reared the turtles in the laboratory until they were 11-18cm long before releasing them in the Gulf Stream off the Floridian coast.
They were then tracked for between 27 and 220 days as they travelled distances from 200 to more than 4300km. The scientists found that they all headed north and remained within or close to the Gulf Stream and tended to travel in clockwise direction around the circular North Atlantic Subtropical Gyre currents.
Some turtles however did move out of these Gyre currents into the centre; an area called the Sargrasso sea. The team suggest that this could be linked to the seasonal drift of Sargassum, a type of macro-algae that floats in large mats and to take advantage of the habitat they offer, in particular the warmth the mats trap at the water surface close to them.
For young turtles, staying warm is of upmost importance. Warmer temperatures help their skeletons grow quicker, making them increasingly less vulnerable.
Therefore the team suggest that where these young turtles headed could have been closely linked to where they could find warmer habitats to boost their growth so that once they are large enough they can return to the coast much less vulnerable than when they left as hatchlings.
“Going with the Flow” or Not: Evidence of Positive Rheotaxis in Oceanic Juvenile Loggerhead Turtles (Caretta caretta) in the South Pacific Ocean Using Satellite Tags and Ocean Circulation Data: here.
Three new turtle and tortoise books for kids encourage adventures: here.
Israeli team designs prosthetic fin to save turtle: here.