Scientists have discovered a new method for examining sex lives and migration patterns of fish – by looking in their ears.

By studying ear stones in fish, which act as tiny data recorders, scientists can now reveal what areas of the oceans the fish have been visiting and insights into their sexual behaviour.

The information could be valuable to scientists, conservationists and fishermen as they attempt to manage fish stocks and require information on the movements of fish in the wild.

Tiny ear stones called otoliths, which are in all bony fish, store chemical elements picked up from the surrounding water.

As fish migrate, changes in the ambient water chemistry are recorded in the otoliths.

Now researchers say they have created a translation dictionary revealing what the different chemical elements stored in the chemical makeup of the stones can tell us about the environments fish have travelled through.

The study is published in Methods in Ecology and Evolution.