Thousands of fish have been rescued and returned to the River Thames during construction of London’s ‘super sewer’.

Construction of the 25 km tunnel, currently underway to help reduce sewage pollution in the river, involves building out new areas of land – or ‘cofferdams’ - into the River Thames.

Before draining the water from these cofferdams to create new areas of dry land, a team of aquatic ecologists from AECOM was tasked with rescuing the fish within them.

So far, more than 5000 fish including carp, bream, roach, smelt, flounder, bleak, pike, gudgeon and sea bass have been returned to the River Thames from sites at Victoria Embankment, Blackfriars Bridge Foreshore and Chelsea Embankment.

The species and sizes of the fish have been recorded, which will help ecologists and the Environment Agency to gain a better understanding of fish populations within the tidal Thames.

Watch our video below to find out more.