Researchers in Spain are tapping into those most harmed by water pollution in efforts to monitor unwanted human chemicals in the water. Using carbon fiber and metal, a European Commission-funded group has built giant yellow fish that swims in a harbor seeking out and reporting on pollution.

"The idea is that we want to have real-time monitoring of pollution, so that if someone is dumping chemicals or something is leaking, we can get to it straight away, find out what is causing the problem and put a stop to it," explained Luke Speller, a senior scientist at the research division of BMT Group, a technology consultancy to BBC.

The robot fish is the latest effort to monitor contamination in a more real-time fashion. Harbor samples are usually taken only once a month, leaving plenty of time for a ship to leak chemicals and make a safe getaway with no consequences.

"A remotely operated device could be deployed quickly and simply in shallow water environments, enabling a rapid response for decision making and remedial action to be taken," says Richard Harrington from the Marine Conservation Society.

The yellow fish is approximately 1.5m long swims just like a fish.

Ian Dukes from the University of Essex explains the reason for not using traditional propellers or thrusters, "Over millions of years, fish have evolved the ultimate hydrodynamic shape, and we have tried to mimic that in the robot. What we're trying to do is use the fin of a fish to propel ourselves through the water."

This allows the fish to move through shallow waters including weeds, reeds, and other obstacles that a normal aquatic robot might not be able to.

The fish can currently detect phenols and heavy metals which include copper and lead. In addition, they also monitor oxygen levels in the water and salinity.

Once one fish detects a problem, it can relay a message back to the port. It can also work as part of a team - relaying messages via acoustic signals to other robot fish nearby which can then pass the message back to headquarters.

Dr.Speller hopes that eventually the robots will do more than just monitor pollution.

"In the future, what I'd also like to see is not just a single task robot, but robots that can multitask - robots that can do search and rescue, monitoring for underwater divers, at the same time as tracking pollution."