Robo-fish are headed for waters of Spain

A school of mechanical, battery-powered robots in the shape of fish will be released into a Spanish port to help monitor pollution there, scientists said Friday.

The 5-foot-long robots work by mimicking the swishing movements of a fish’s tail, according to University of Essex robotics expert Huosheng Hu, whose team is manufacturing the machines.

He said the robo-fish would be equipped with sensors to monitor oxygen levels in the water, detect oil slicks spilled from ships or contaminants pumped into the water from underground pipes.

They will patrol the harbor of Gijon, in northern Spain, under a $3.6-million grant from the European Union.

Hu said Gijon was chosen because officials had expressed interest in the technology.

Information gathered from the robo-fish will be transmitted to the port’s control center using a wireless Internet signal when the devices surface.

The fish won’t need remote guidance -- their sensors can help them avoid obstacles such as rocks and ships, said Rory Doyle of the engineering consultancy BMT Group, a member of a consortium manufacturing the machines.

The fish can also swap navigational information with one another using a form of sonar. When their batteries are nearing the end of their eight-hour capacity, they can swim back to a power hub to recharge.

Each fish costs about $28,000 to make, and BMT estimated their maximum speed at about a yard per second.

Hu hopes to release the robo-fish into the water within the next 18 months.