Sea turtles hatch on a beach, scuttle to the sea and swim away. Many years later, they return as adults to the beaches of their birth to lay the eggs destined – if they are lucky – to grow up and become the next generation of turtles. But what happens in between? Where do they go? What do they do?
Some recent research on loggerhead turtles hatched in Florida and followed with the aid of small, solar-powered radio beacons showed that at least some of them spend time in the calm, weedy waters of the Sargasso Sea in the mid-Atlantic.
Even then the mystery is far from solved, because not every loggerhead turtle nests in Florida. And there are other animals, such as salmon and eels, that complete migrations to and from inshore waters and open ocean.
Though European eels are thought to hatch in the Sargasso Sea, the oceanic nursery of the Japanese eel was a complete mystery for many years until patient research showed that it was in the vicinity of the Mariana Trench in the Pacific Ocean.
It is worth remembering that oceans cover about three-quarters of our planet’s surface – it’s a fair bet that their waters will be the source of many of the Earth’s remaining wildlife mysteries.