Fish conservation in the tidal Thames

The Tidal Thames, running from Teddington lock in the west of London, to the North Sea, is home to more than 100 fish species, many of which are commercially and ecologically important.

 
Species calling the Thames home include endangered species such as European eels, seabass, flounder, and smelt. The Thames is used as a nursery habitat, and a pathway between freshwater habitats and the open seas – making this area absolutely vital to the success of UK fish species and their conservation. 

However, like other estuarine habitats, this region remains poorly studied and there is a need to further our understanding of the ways in which fish are using the river in order to protect vulnerable populations from continued threats such as habitat loss, poor water quality and development activities.

ZSL is working to conserve fish in the tidal Thames

Since 2015 ZSL has been studying fish in the tidal Thames with special focus on spawning grounds and the seasonal variations in juvenile fish presence and distribution. To date, we have conducted the most comprehensive studies of juvenile fish in any estuary in the UK, identified a previously unknown spawning habitat for smelt, an estuarine indicator species, and tagged the first fish to swim through central London. Through this work we have provided a benchmark to measure the health of fish populations over time. 

It is clear from our research the entire tidal Thames is essential to fish in their early life stages, from the central areas when they are just larvae and unable to swim, right to the extreme margins where the juveniles and adults rest and hide from the strong tides. 

To ensure that important life stages of fish species and their habitats are protected in the Tidal Thames, we have published a Guidance Document on Conservation of Tidal Thames fish through the Planning Process. This document provides a single point of reference to developers, planners, Biodiversity Officers and consultants on how fish should be considered when planning developments on or beside the river.

Learn more about our tidal Thames fish conservation 

• Our guide to fish species found in shore-based sampling of UK estuaries
• Our summary report of larval and juvenile fish in the tidal Thames 
• Our modelling report of smelt in the tidal Thames