In the shallow waters of Gijon harbour, in northern Spain, a large, yellow fish cuts through the waves.

But this swimmer stands apart from the marine life that usually inhabits this port: there’s no flesh and blood here, just carbon fibre and metal.

This is robo-fish – scientists’ latest weapon in the war against pollution.

The fish-shaped robot can swim in shallow water and weedy water, which would normally snag on propellers, and contains sensors to hunt down pollution.  The advantage is that it can be left in the harbour all the time – far better than testing the water once a month.  And with live data-streaming to its control centre, leaks and illegal dumpings can be spotted and fixed in record time.

Not only that, but these fish have teamwork down pat.  They use acoustic signals to communicate with each other, and use AI to find the source of the pollution.  Not advanced, general AI, I hope, because otherwise they might rise up and overthrow their creators.

Current problems include the cost (£20,000 per fish!) and the fact that they need to be recharged every 8 hours.  But the researchers expect to have those problems fixed soon.  So, next time you have fish for dinner, make sure you check it for wires and sensors!