Robotic fish to monitor pollution in harbours
22 May 2012 Last updated at 06:53 BST
The cost of water pollution in the UK runs into millions of pounds each year, and it can cause untold damage to the environment.
But now scientists have come up with an unusual solution to the problem and it comes in the shape of a robotic fish.
Luke Speller from the Shoal Consortium explains how it works.
Produced by the BBC's Dave O'Neill and Rebecca Morelle