Hayling Island pebbles tracked by scientists
Electronically-tagged pebbles have been scattered on the shore at Hayling Island, Hampshire, to track the movement of beach material.
The 2,600 flint pebbles along the 4.9 miles (8km) of coast will be tracked by scientists using GPS scanners.
The pebbles have been cut with a water jet and filled with ID chips similar to those used to tag pets.
The tracer pebble study aims to follow the stones to help prevent flooding to the island's seafront properties.
Clive Moon, coastal engineer, said: "The pebbles move rapidly - around 120m to 150m in just one tidal cycle - but they don't always move in the same direction.
"One day they may go west and another they may go east."
The technology inside the pebbles is expected to last for several decades.
The greatest distance travelled by a single pebble along the shore is currently 1.7 miles (2.8km).
The island's coast loses between 25,000 and 50,000 cubic metres of sand, single and pebbles each year.
The shingle on the boot-shaped island's beach is topped up annually by dumper trucks.
Every five years the area is "nourished", whereby material dredged from the seabed is sprayed directly back onto the beach.