Robot "fish" developed by European scientists to improve pollution monitoring moved from the lab to the sea in a test at the northern Spanish port of Gijon on Tuesday, Reuters reported.

The robotic fish, a state-of-the-art pollution monitoring system. [Agencies]

The fish could detect a pollutant in seconds, and could also have spin-offs for cleaning up oil spills, underwater security, diver monitoring or search and rescue at sea.

The fish are 1.5 meters long and cost $31,600 each. They swim independently, co-ordinate with each other, and transmit their readings back to a shore station up to a kilometer away.

The fish can avoid obstacles, map where they are and know how to return to base when their eight-hour battery life is running low, their makers say.